/// DreamStack CLI — the compiler command-line interface.
///
/// Usage:
///   dreamstack build <file.ds>   — compile to HTML+JS
///   dreamstack dev <file.ds>     — dev server with hot reload
///   dreamstack check <file.ds>   — analyze without emitting

use clap::{Parser, Subcommand};
use std::fs;
use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex, atomic::{AtomicU64, Ordering}};
use std::time::{Duration, Instant};

#[derive(Parser)]
#[command(name = "dreamstack")]
#[command(about = "The DreamStack UI compiler", version = "0.1.0")]
struct Cli {
    #[command(subcommand)]
    command: Commands,
}

#[derive(Subcommand)]
enum Commands {
    /// Compile a .ds file to HTML+JS
    Build {
        /// Input .ds file
        file: PathBuf,
        /// Output directory (default: dist/)
        #[arg(short, long, default_value = "dist")]
        output: PathBuf,
    },
    /// Start a dev server with hot reload
    Dev {
        /// Input .ds file
        file: PathBuf,
        /// Port to serve on
        #[arg(short, long, default_value_t = 3000)]
        port: u16,
    },
    /// Type-check and analyze without compiling
    Check {
        /// Input .ds file
        file: PathBuf,
    },
    /// Compile and stream a .ds file via bitstream relay
    Stream {
        /// Input .ds file
        file: PathBuf,
        /// WebSocket relay URL
        #[arg(short, long, default_value = "ws://localhost:9100")]
        relay: String,
        /// Stream mode: pixel | delta | signal
        #[arg(short, long, default_value = "signal")]
        mode: String,
        /// Port to serve the source page on
        #[arg(short, long, default_value_t = 3000)]
        port: u16,
    },
    /// Launch the interactive playground with Monaco editor
    Playground {
        /// Optional .ds file to pre-load
        file: Option<PathBuf>,
        /// Port to serve on
        #[arg(short, long, default_value_t = 4000)]
        port: u16,
    },
    /// Add a component from the DreamStack registry
    Add {
        /// Component name (e.g., button, card, dialog) or --list to show available
        name: Option<String>,
        /// List all available components
        #[arg(long)]
        list: bool,
        /// Add all registry components
        #[arg(long)]
        all: bool,
    },
    /// Convert a React/TSX component to DreamStack .ds format
    Convert {
        /// Input .tsx file path, or component name with --shadcn
        name: String,
        /// Fetch from shadcn/ui registry instead of local file
        #[arg(long)]
        shadcn: bool,
        /// Output file path (default: stdout)
        #[arg(short, long)]
        output: Option<PathBuf>,
    },
}

fn main() {
    let cli = Cli::parse();

    match cli.command {
        Commands::Build { file, output } => cmd_build(&file, &output),
        Commands::Dev { file, port } => cmd_dev(&file, port),
        Commands::Check { file } => cmd_check(&file),
        Commands::Stream { file, relay, mode, port } => cmd_stream(&file, &relay, &mode, port),
        Commands::Playground { file, port } => cmd_playground(file.as_deref(), port),
        Commands::Add { name, list, all } => cmd_add(name, list, all),
        Commands::Convert { name, shadcn, output } => cmd_convert(&name, shadcn, output.as_deref()),
    }
}

fn compile(source: &str, base_dir: &Path) -> Result<String, String> {
    // 1. Lex
    let mut lexer = ds_parser::Lexer::new(source);
    let tokens = lexer.tokenize();

    // Check for lexer errors
    for tok in &tokens {
        if let ds_parser::TokenKind::Error(msg) = &tok.kind {
            return Err(format!("Lexer error at line {}: {}", tok.line, msg));
        }
    }

    // 2. Parse
    let mut parser = ds_parser::Parser::new(tokens);
    let mut program = parser.parse_program().map_err(|e| e.to_string())?;

    // 3. Resolve imports — inline exported declarations from imported files
    resolve_imports(&mut program, base_dir)?;

    // 4. Analyze
    let graph = ds_analyzer::SignalGraph::from_program(&program);
    let views = ds_analyzer::SignalGraph::analyze_views(&program);

    // 5. Codegen
    let html = ds_codegen::JsEmitter::emit_html(&program, &graph, &views);

    Ok(html)
}

/// Resolve `import { X, Y } from "./file"` by parsing the imported file
/// and inlining the matching `export`ed declarations.
fn resolve_imports(program: &mut ds_parser::Program, base_dir: &Path) -> Result<(), String> {
    use std::collections::HashSet;

    let mut imported_decls = Vec::new();
    let mut seen_files: HashSet<PathBuf> = HashSet::new();

    for decl in &program.declarations {
        if let ds_parser::Declaration::Import(import) = decl {
            // Resolve the file path relative to base_dir
            let mut import_path = base_dir.join(&import.source);
            if !import_path.extension().map_or(false, |e| e == "ds") {
                import_path.set_extension("ds");
            }

            let import_path = import_path.canonicalize().unwrap_or(import_path.clone());

            if seen_files.contains(&import_path) {
                continue; // Skip duplicate imports
            }
            seen_files.insert(import_path.clone());

            // Read and parse the imported file
            let imported_source = fs::read_to_string(&import_path)
                .map_err(|e| format!("Cannot import '{}': {}", import.source, e))?;

            let mut lexer = ds_parser::Lexer::new(&imported_source);
            let tokens = lexer.tokenize();
            for tok in &tokens {
                if let ds_parser::TokenKind::Error(msg) = &tok.kind {
                    return Err(format!("Lexer error in '{}' at line {}: {}", import.source, tok.line, msg));
                }
            }
            let mut parser = ds_parser::Parser::new(tokens);
            let mut imported_program = parser.parse_program()
                .map_err(|e| format!("Parse error in '{}': {}", import.source, e))?;

            // Recursively resolve imports in the imported file
            let imported_dir = import_path.parent().unwrap_or(base_dir);
            resolve_imports(&mut imported_program, imported_dir)?;

            // Extract matching exports
            let names: HashSet<&str> = import.names.iter().map(|s| s.as_str()).collect();
            for d in &imported_program.declarations {
                match d {
                    ds_parser::Declaration::Export(name, inner) if names.contains(name.as_str()) => {
                        imported_decls.push(*inner.clone());
                    }
                    // Also include non-exported decls that exports depend on
                    // (for now, include all let decls from the imported file)
                    ds_parser::Declaration::Let(_) => {
                        imported_decls.push(d.clone());
                    }
                    _ => {}
                }
            }
        }
    }

    // Remove Import declarations and prepend imported decls
    program.declarations.retain(|d| !matches!(d, ds_parser::Declaration::Import(_)));
    let mut merged = imported_decls;
    merged.append(&mut program.declarations);
    program.declarations = merged;

    Ok(())
}

fn cmd_build(file: &Path, output: &Path) {
    println!("🔨 DreamStack build");
    println!("   source: {}", file.display());

    let source = match fs::read_to_string(file) {
        Ok(s) => s,
        Err(e) => {
            eprintln!("❌ Could not read {}: {}", file.display(), e);
            std::process::exit(1);
        }
    };

    let base_dir = file.parent().unwrap_or(Path::new("."));
    match compile(&source, base_dir) {
        Ok(html) => {
            fs::create_dir_all(output).unwrap();
            let out_path = output.join("index.html");
            fs::write(&out_path, &html).unwrap();
            println!("   output: {}", out_path.display());
            println!("✅ Build complete! ({} bytes)", html.len());
            println!();
            println!("   Open in browser:");
            println!("   file://{}", fs::canonicalize(&out_path).unwrap().display());
        }
        Err(e) => {
            eprintln!("❌ Compile error: {e}");
            std::process::exit(1);
        }
    }
}

/// HMR client script injected into every page served by `dreamstack dev`.
/// Uses Server-Sent Events to receive reload notifications from the dev server.
const HMR_CLIENT_SCRIPT: &str = r#"
<script>
// ── DreamStack HMR (poll-based) ─────────────
(function() {
  let currentVersion = null;
  let polling = false;

  async function poll() {
    if (polling) return;
    polling = true;
    try {
      const res = await fetch('/__hmr');
      const version = await res.text();
      if (currentVersion === null) {
        currentVersion = version;
        console.log('[DS HMR] 🟢 watching (v' + version + ')');
      } else if (version !== currentVersion) {
        console.log('[DS HMR] 🔄 change detected (v' + currentVersion + ' → v' + version + '), reloading...');
        location.reload();
        return;
      }
    } catch(e) {
      // server down — retry silently
    }
    polling = false;
  }

  setInterval(poll, 500);
  poll();
})();
</script>
"#;

fn inject_hmr(html: &str) -> String {
    // Inject the HMR script just before </body>
    if let Some(pos) = html.rfind("</body>") {
        format!("{}{}{}", &html[..pos], HMR_CLIENT_SCRIPT, &html[pos..])
    } else {
        // No </body> tag — just append
        format!("{html}{HMR_CLIENT_SCRIPT}")
    }
}

fn cmd_dev(file: &Path, port: u16) {
    use notify::{Watcher, RecursiveMode};
    use std::sync::mpsc;
    use std::thread;

    println!("🚀 DreamStack dev server");
    println!("   watching: {}", file.display());
    println!("   serving:  http://localhost:{port}");
    println!();

    // Shared state: compiled HTML + version counter
    let version = Arc::new(AtomicU64::new(1));
    let compiled_html = Arc::new(Mutex::new(String::new()));

    // Initial compile
    let source = match fs::read_to_string(file) {
        Ok(s) => s,
        Err(e) => {
            eprintln!("❌ Could not read {}: {}", file.display(), e);
            std::process::exit(1);
        }
    };

    let start = Instant::now();
    let base_dir = file.parent().unwrap_or(Path::new("."));
    match compile(&source, base_dir) {
        Ok(html) => {
            let ms = start.elapsed().as_millis();
            let html_with_hmr = inject_hmr(&html);
            *compiled_html.lock().unwrap() = html_with_hmr;
            println!("✅ Compiled in {ms}ms ({} bytes)", html.len());
        }
        Err(e) => {
            eprintln!("⚠️  Compile error: {e}");
            let error_html = format!(
                r#"<!DOCTYPE html>
<html><head><meta charset="UTF-8"><style>
body {{ background: #0a0a0f; color: #ef4444; font-family: 'JetBrains Mono', monospace; padding: 40px; }}
pre {{ white-space: pre-wrap; line-height: 1.7; }}
h2 {{ color: #f87171; margin-bottom: 16px; }}
</style></head><body>
<h2>── COMPILE ERROR ──</h2>
<pre>{e}</pre>
</body></html>"#
            );
            *compiled_html.lock().unwrap() = inject_hmr(&error_html);
        }
    }

    // ── File Watcher Thread ─────────────────────────
    let file_path = fs::canonicalize(file).unwrap_or_else(|_| file.to_path_buf());
    let watch_dir = file_path.parent().unwrap().to_path_buf();
    let watch_file = file_path.clone();
    let v_watcher = Arc::clone(&version);
    let html_watcher = Arc::clone(&compiled_html);

    thread::spawn(move || {
        let (tx, rx) = mpsc::channel();

        let mut watcher = notify::recommended_watcher(move |res: Result<notify::Event, notify::Error>| {
            if let Ok(event) = res {
                let _ = tx.send(event);
            }
        }).expect("Failed to create file watcher");

        watcher.watch(&watch_dir, RecursiveMode::NonRecursive)
            .expect("Failed to watch directory");

        println!("👁  Watching {} for changes", watch_dir.display());
        println!();

        // Debounce: coalesce rapid events
        let mut last_compile = Instant::now();

        loop {
            match rx.recv_timeout(Duration::from_millis(100)) {
                Ok(event) => {
                    // Only recompile for .ds file changes
                    let dominated = event.paths.iter().any(|p| {
                        p == &watch_file ||
                        p.extension().map_or(false, |ext| ext == "ds")
                    });

                    if !dominated { continue; }

                    // Debounce: skip if less than 100ms since last compile
                    if last_compile.elapsed() < Duration::from_millis(100) {
                        continue;
                    }

                    // Recompile
                    if let Ok(src) = fs::read_to_string(&watch_file) {
                        let start = Instant::now();
                        match compile(&src, watch_file.parent().unwrap_or(Path::new("."))) {
                            Ok(html) => {
                                let ms = start.elapsed().as_millis();
                                let new_version = v_watcher.fetch_add(1, Ordering::SeqCst) + 1;
                                *html_watcher.lock().unwrap() = inject_hmr(&html);
                                println!("🔄 Recompiled in {ms}ms (v{new_version}, {} bytes)", html.len());
                                last_compile = Instant::now();
                            }
                            Err(e) => {
                                let new_version = v_watcher.fetch_add(1, Ordering::SeqCst) + 1;
                                let error_html = format!(
                                    r#"<!DOCTYPE html>
<html><head><meta charset="UTF-8"><style>
body {{ background: #0a0a0f; color: #ef4444; font-family: 'JetBrains Mono', monospace; padding: 40px; }}
pre {{ white-space: pre-wrap; line-height: 1.7; }}
h2 {{ color: #f87171; margin-bottom: 16px; }}
</style></head><body>
<h2>── COMPILE ERROR ──</h2>
<pre>{e}</pre>
</body></html>"#
                                );
                                *html_watcher.lock().unwrap() = inject_hmr(&error_html);
                                eprintln!("❌ v{new_version}: {e}");
                                last_compile = Instant::now();
                            }
                        }
                    }
                }
                Err(mpsc::RecvTimeoutError::Timeout) => {
                    // No events — loop and check again
                    continue;
                }
                Err(mpsc::RecvTimeoutError::Disconnected) => break,
            }
        }
    });

    // ── HTTP Server ─────────────────────────────────
    let server = tiny_http::Server::http(format!("0.0.0.0:{port}")).unwrap();
    println!("✅ Server running at http://localhost:{port}");
    println!("   Press Ctrl+C to stop");
    println!();

    for request in server.incoming_requests() {
        let url = request.url().to_string();

        if url == "/__hmr" {
            // Version endpoint for HMR polling
            let v = version.load(Ordering::SeqCst);
            let response = tiny_http::Response::from_string(format!("{v}"))
                .with_header(
                    tiny_http::Header::from_bytes(
                        &b"Content-Type"[..],
                        &b"text/plain"[..],
                    ).unwrap(),
                )
                .with_header(
                    tiny_http::Header::from_bytes(
                        &b"Cache-Control"[..],
                        &b"no-cache, no-store"[..],
                    ).unwrap(),
                );
            let _ = request.respond(response);
        } else {
            // Serve the compiled HTML
            let html = compiled_html.lock().unwrap().clone();
            let response = tiny_http::Response::from_string(&html)
                .with_header(
                    tiny_http::Header::from_bytes(
                        &b"Content-Type"[..],
                        &b"text/html; charset=utf-8"[..],
                    ).unwrap(),
                );
            let _ = request.respond(response);
        }
    }
}

fn cmd_check(file: &Path) {
    println!("🔍 DreamStack check");
    println!("   file: {}", file.display());

    let source = match fs::read_to_string(file) {
        Ok(s) => s,
        Err(e) => {
            eprintln!("❌ Could not read {}: {}", file.display(), e);
            std::process::exit(1);
        }
    };

    // Lex
    let mut lexer = ds_parser::Lexer::new(&source);
    let tokens = lexer.tokenize();

    let mut errors = 0;
    for tok in &tokens {
        if let ds_parser::TokenKind::Error(msg) = &tok.kind {
            eprintln!("  ❌ Lexer error at line {}: {}", tok.line, msg);
            errors += 1;
        }
    }

    // Parse
    let mut parser = ds_parser::Parser::new(tokens);
    let program = match parser.parse_program() {
        Ok(p) => p,
        Err(e) => {
            eprintln!("  ❌ {}", e);
            std::process::exit(1);
        }
    };

    // Analyze
    let graph = ds_analyzer::SignalGraph::from_program(&program);
    let views = ds_analyzer::SignalGraph::analyze_views(&program);

    println!();
    println!("   📊 Signal Graph:");
    for node in &graph.nodes {
        let kind_str = match &node.kind {
            ds_analyzer::SignalKind::Source => "source",
            ds_analyzer::SignalKind::Derived => "derived",
            ds_analyzer::SignalKind::Handler { .. } => "handler",
        };
        let deps: Vec<&str> = node.dependencies.iter().map(|d| d.signal_name.as_str()).collect();
        if deps.is_empty() {
            println!("     {} [{}]", node.name, kind_str);
        } else {
            println!("     {} [{}] ← depends on: {}", node.name, kind_str, deps.join(", "));
        }
    }

    println!();
    println!("   🖼️  Views:");
    for view in &views {
        println!("     {} ({} bindings)", view.name, view.bindings.len());
        for binding in &view.bindings {
            match &binding.kind {
                ds_analyzer::BindingKind::TextContent { signal } => {
                    println!("       📝 text bound to: {signal}");
                }
                ds_analyzer::BindingKind::EventHandler { element_tag, event, .. } => {
                    println!("       ⚡ {element_tag}.{event}");
                }
                ds_analyzer::BindingKind::Conditional { condition_signals } => {
                    println!("       ❓ conditional on: {}", condition_signals.join(", "));
                }
                ds_analyzer::BindingKind::StaticContainer { kind, child_count } => {
                    println!("       📦 {kind} ({child_count} children)");
                }
                ds_analyzer::BindingKind::StaticText { text } => {
                    println!("       📄 static: \"{text}\"");
                }
            }
        }
    }

    let topo = graph.topological_order();
    println!();
    println!("   🔄 Propagation order: {:?}", topo.iter().map(|&id| &graph.nodes[id].name).collect::<Vec<_>>());

    if errors == 0 {
        println!();
        println!("✅ No errors found");
    } else {
        println!();
        eprintln!("❌ {} error(s) found", errors);
        std::process::exit(1);
    }
}

fn cmd_stream(file: &Path, relay: &str, mode: &str, port: u16) {
    println!("⚡ DreamStack stream");
    println!("   source: {}", file.display());
    println!("   relay:  {}", relay);
    println!("   mode:   {}", mode);
    println!("   port:   {}", port);
    println!();

    let source = match fs::read_to_string(file) {
        Ok(s) => s,
        Err(e) => {
            eprintln!("❌ Could not read {}: {}", file.display(), e);
            std::process::exit(1);
        }
    };

    // Inject stream declaration if not present
    let stream_source = if source.contains("stream ") {
        source
    } else {
        // Auto-inject a stream declaration for the first view
        let view_name = {
            let mut lexer = ds_parser::Lexer::new(&source);
            let tokens = lexer.tokenize();
            let mut parser = ds_parser::Parser::new(tokens);
            if let Ok(program) = parser.parse_program() {
                program.declarations.iter()
                    .find_map(|d| if let ds_parser::ast::Declaration::View(v) = d { Some(v.name.clone()) } else { None })
                    .unwrap_or_else(|| "main".to_string())
            } else {
                "main".to_string()
            }
        };
        format!(
            "{}\nstream {} on \"{}\" {{ mode: {} }}",
            source, view_name, relay, mode
        )
    };

    match compile(&stream_source, file.parent().unwrap_or(Path::new("."))) {
        Ok(html) => {
            let html_with_hmr = inject_hmr(&html);
            println!("✅ Compiled with streaming enabled");
            println!("   Open: http://localhost:{port}");
            println!("   Relay: {relay}");
            println!();
            println!("   Make sure the relay is running:");
            println!("   cargo run -p ds-stream");
            println!();

            // Serve the compiled page
            let server = tiny_http::Server::http(format!("0.0.0.0:{port}")).unwrap();
            for request in server.incoming_requests() {
                let response = tiny_http::Response::from_string(&html_with_hmr)
                    .with_header(
                        tiny_http::Header::from_bytes(
                            &b"Content-Type"[..],
                            &b"text/html; charset=utf-8"[..],
                        ).unwrap(),
                    );
                let _ = request.respond(response);
            }
        }
        Err(e) => {
            eprintln!("❌ Compile error: {e}");
            std::process::exit(1);
        }
    }
}

// ── Playground ──────────────────────────────────────────────

/// The playground HTML page with Monaco editor + live preview.
const PLAYGROUND_HTML: &str = r##"<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>DreamStack Playground</title>
<link href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet">
<style>
  * { margin: 0; padding: 0; box-sizing: border-box; }

  :root {
    --bg: #0a0a12;
    --surface: #12121e;
    --surface-2: #1a1a2e;
    --border: #2a2a3e;
    --text: #e4e4ef;
    --text-dim: #888899;
    --accent: #818cf8;
    --accent-glow: rgba(129,140,248,0.15);
    --green: #34d399;
    --red: #f87171;
    --yellow: #fbbf24;
  }

  html, body { height: 100%; background: var(--bg); color: var(--text); font-family: 'Inter', sans-serif; overflow: hidden; }

  /* Header */
  .header {
    height: 52px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 20px;
    gap: 16px;
    z-index: 100;
  }
  .header .logo {
    font-size: 16px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent), #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.5px;
  }
  .header .sep { width: 1px; height: 24px; background: var(--border); }
  .header .status {
    font-size: 12px;
    font-family: 'JetBrains Mono', monospace;
    color: var(--text-dim);
    display: flex;
    align-items: center;
    gap: 8px;
  }
  .header .status .dot {
    width: 7px; height: 7px;
    border-radius: 50%;
    background: var(--green);
    box-shadow: 0 0 6px rgba(52,211,153,0.5);
    transition: background 0.3s, box-shadow 0.3s;
  }
  .header .status .dot.error {
    background: var(--red);
    box-shadow: 0 0 6px rgba(248,113,113,0.5);
  }
  .header .status .dot.compiling {
    background: var(--yellow);
    box-shadow: 0 0 6px rgba(251,191,36,0.5);
    animation: pulse 0.6s ease-in-out infinite;
  }
  @keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.4; } }

  .header .actions { margin-left: auto; display: flex; gap: 8px; }
  .header .btn {
    padding: 6px 14px;
    border-radius: 6px;
    border: 1px solid var(--border);
    background: var(--surface-2);
    color: var(--text);
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    cursor: pointer;
    transition: all 0.15s;
  }
  .header .btn:hover { border-color: var(--accent); background: var(--accent-glow); }
  .header .btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
  .header .btn.primary:hover { opacity: 0.9; }

  /* Layout */
  .container {
    display: flex;
    height: calc(100vh - 52px);
  }
  .editor-pane {
    width: 50%;
    min-width: 300px;
    position: relative;
    border-right: 1px solid var(--border);
  }
  .preview-pane {
    flex: 1;
    position: relative;
    background: #fff;
  }
  #previewRoot {
    width: 100%;
    height: 100%;
    overflow: auto;
  }

  /* Resize handle */
  .resize-handle {
    position: absolute;
    right: -3px;
    top: 0;
    width: 6px;
    height: 100%;
    cursor: col-resize;
    z-index: 10;
    background: transparent;
    transition: background 0.2s;
  }
  .resize-handle:hover, .resize-handle.active {
    background: var(--accent);
  }

  /* Error panel */
  .error-panel {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    max-height: 40%;
    background: rgba(10,10,18,0.97);
    border-top: 2px solid var(--red);
    overflow-y: auto;
    z-index: 20;
    display: none;
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    padding: 16px 20px;
    color: var(--red);
    line-height: 1.6;
    white-space: pre-wrap;
  }
  .error-panel.visible { display: block; }

  /* Monaco loader */
  #editor { width: 100%; height: 100%; }
</style>
</head>
<body>

<div class="header">
  <span class="logo">DreamStack</span>
  <span class="sep"></span>
  <div class="status">
    <span class="dot" id="statusDot"></span>
    <span id="statusText">Ready</span>
  </div>
  <div class="actions">
    <button class="btn" onclick="formatCode()">Format</button>
    <button class="btn primary" onclick="compileNow()">Compile ⌘↵</button>
  </div>
</div>

<div class="container">
  <div class="editor-pane" id="editorPane">
    <div id="editor"></div>
    <div class="resize-handle" id="resizeHandle"></div>
    <div class="error-panel" id="errorPanel"></div>
  </div>
  <div class="preview-pane" id="previewPane">
    <div id="previewRoot"></div>
  </div>
</div>

<script src="https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs/loader.js"></script>
<script>
  // ── State ──
  let editor;
  let compileTimer = null;
  const DEBOUNCE_MS = 400;

  // ── Monaco Setup ──
  require.config({ paths: { vs: 'https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs' }});

  require(['vs/editor/editor.main'], function () {
    // Register DreamStack language
    monaco.languages.register({ id: 'dreamstack' });
    monaco.languages.setMonarchTokensProvider('dreamstack', {
      keywords: ['let','view','when','match','on','effect','perform','handle','import','export',
                 'if','else','every','type','where','stream','from','layout','component','for','in'],
      typeKeywords: ['Int','Float','String','Bool','Signal','Derived','Array','Stream','View'],
      operators: ['=','>','<','>=','<=','==','!=','+','-','*','/','%','|>','->','!','&&','||'],
      tokenizer: {
        root: [
          [/\/\/.*$/, 'comment'],
          [/"([^"\\]|\\.)*"/, 'string'],
          [/\d+\.\d+/, 'number.float'],
          [/\d+/, 'number'],
          [/[a-zA-Z_]\w*/, {
            cases: {
              '@keywords': 'keyword',
              '@typeKeywords': 'type',
              '@default': 'identifier'
            }
          }],
          [/[{}()\[\]]/, 'delimiter.bracket'],
          [/[,;:]/, 'delimiter'],
          [/[=><!+\-*\/%|&]+/, 'operator'],
          [/\s+/, 'white'],
        ]
      }
    });

    // Define DreamStack theme
    monaco.editor.defineTheme('dreamstack-dark', {
      base: 'vs-dark',
      inherit: true,
      rules: [
        { token: 'keyword', foreground: '818cf8', fontStyle: 'bold' },
        { token: 'type', foreground: '34d399' },
        { token: 'string', foreground: 'fbbf24' },
        { token: 'number', foreground: 'f472b6' },
        { token: 'number.float', foreground: 'f472b6' },
        { token: 'comment', foreground: '555566', fontStyle: 'italic' },
        { token: 'operator', foreground: '94a3b8' },
        { token: 'delimiter', foreground: '64748b' },
        { token: 'identifier', foreground: 'e4e4ef' },
      ],
      colors: {
        'editor.background': '#0a0a12',
        'editor.foreground': '#e4e4ef',
        'editor.lineHighlightBackground': '#1a1a2e',
        'editorLineNumber.foreground': '#3a3a4e',
        'editorLineNumber.activeForeground': '#818cf8',
        'editor.selectionBackground': '#818cf833',
        'editorCursor.foreground': '#818cf8',
        'editorIndentGuide.background': '#1e1e30',
      }
    });

    // Create editor
    editor = monaco.editor.create(document.getElementById('editor'), {
      value: INITIAL_SOURCE,
      language: 'dreamstack',
      theme: 'dreamstack-dark',
      fontFamily: "'JetBrains Mono', monospace",
      fontSize: 14,
      lineHeight: 24,
      padding: { top: 16 },
      minimap: { enabled: false },
      scrollBeyondLastLine: false,
      renderLineHighlight: 'all',
      cursorBlinking: 'smooth',
      cursorSmoothCaretAnimation: 'on',
      smoothScrolling: true,
      tabSize: 2,
      wordWrap: 'on',
      automaticLayout: true,
    });

    // Auto-compile on change
    editor.onDidChangeModelContent(() => {
      clearTimeout(compileTimer);
      compileTimer = setTimeout(compileNow, DEBOUNCE_MS);
    });

    // Keyboard shortcut: Cmd/Ctrl + Enter
    editor.addCommand(monaco.KeyMod.CtrlCmd | monaco.KeyCode.Enter, compileNow);

    // Initial compile
    compileNow();
  });

  // ── Compile ──
  let compiling = false;
  async function compileNow() {
    if (compiling || !editor) return;
    compiling = true;

    const dot = document.getElementById('statusDot');
    const text = document.getElementById('statusText');
    const errorPanel = document.getElementById('errorPanel');

    dot.className = 'dot compiling';
    text.textContent = 'Compiling...';

    const source = editor.getValue();
    const start = performance.now();

    try {
      const res = await fetch('/compile', {
        method: 'POST',
        headers: { 'Content-Type': 'text/plain' },
        body: source,
      });

      const ms = (performance.now() - start).toFixed(0);
      const data = await res.json();

      if (data.type === 'full') {
        const root = document.getElementById('previewRoot');
        // Parse HTML and extract body + scripts
        const parser = new DOMParser();
        const doc = parser.parseFromString(data.html, 'text/html');
        // Attach or reuse shadow root
        if (!root.shadowRoot) root.attachShadow({ mode: 'open' });
        const shadow = root.shadowRoot;
        shadow.innerHTML = '';
        // Copy styles into shadow
        doc.querySelectorAll('style').forEach(s => shadow.appendChild(s.cloneNode(true)));
        // Copy body content into shadow
        const wrapper = document.createElement('div');
        wrapper.innerHTML = doc.body.innerHTML;
        shadow.appendChild(wrapper);
        // Execute scripts in main window context (where DS signals live)
        doc.querySelectorAll('script').forEach(s => {
          try { new Function(s.textContent)(); } catch(e) { console.warn('Script error:', e); }
        });
        dot.className = 'dot';
        text.textContent = `Full compile ${ms}ms`;
        errorPanel.classList.remove('visible');
      } else if (data.type === 'patch') {
        if (data.js && data.js.length > 0) {
          try {
            new Function(data.js)();
          } catch (e) { console.warn('Patch eval error:', e); }
        }
        dot.className = 'dot';
        text.textContent = `Patched ${ms}ms ⚡`;
        errorPanel.classList.remove('visible');
      } else if (data.type === 'error') {
        dot.className = 'dot error';
        text.textContent = `Error (${ms}ms)`;
        errorPanel.textContent = data.message;
        errorPanel.classList.add('visible');
      }
    } catch (e) {
      dot.className = 'dot error';
      text.textContent = 'Network error';
      errorPanel.textContent = e.message;
      errorPanel.classList.add('visible');
    }

    compiling = false;
  }

  function formatCode() {
    if (editor) editor.getAction('editor.action.formatDocument')?.run();
  }

  // ── Resize Handle ──
  const handle = document.getElementById('resizeHandle');
  const editorPane = document.getElementById('editorPane');
  let resizing = false;

  handle.addEventListener('mousedown', (e) => {
    resizing = true;
    handle.classList.add('active');
    document.body.style.cursor = 'col-resize';
    document.body.style.userSelect = 'none';
    e.preventDefault();
  });

  window.addEventListener('mousemove', (e) => {
    if (!resizing) return;
    const pct = (e.clientX / window.innerWidth) * 100;
    const clamped = Math.max(25, Math.min(75, pct));
    editorPane.style.width = clamped + '%';
  });

  window.addEventListener('mouseup', () => {
    resizing = false;
    handle.classList.remove('active');
    document.body.style.cursor = '';
    document.body.style.userSelect = '';
  });
</script>
</body>
</html>
"##;

fn cmd_playground(file: Option<&Path>, port: u16) {
    println!("🎮 DreamStack Playground");
    println!("   http://localhost:{port}");
    println!();

    // Load initial source from file or use default
    let initial_source = if let Some(path) = file {
        match fs::read_to_string(path) {
            Ok(s) => {
                println!("   loaded: {}", path.display());
                s
            }
            Err(e) => {
                eprintln!("⚠️  Could not read {}: {e}", path.display());
                default_playground_source()
            }
        }
    } else {
        default_playground_source()
    };

    // Build the playground HTML with the initial source injected
    let escaped_source = initial_source
        .replace('\\', "\\\\")
        .replace('`', "\\`")
        .replace("${", "\\${");
    let playground_html = PLAYGROUND_HTML.replace(
        "INITIAL_SOURCE",
        &format!("String.raw`{}`", escaped_source),
    );

    let server = tiny_http::Server::http(format!("0.0.0.0:{port}")).unwrap();
    println!("✅ Playground running at http://localhost:{port}");
    println!("   Press Ctrl+C to stop");
    println!();

    let base_dir = file.and_then(|f| f.parent()).unwrap_or(Path::new("."));
    let base_dir = base_dir.to_path_buf();
    let mut inc_compiler = ds_incremental::IncrementalCompiler::new();

    for mut request in server.incoming_requests() {
        let url = request.url().to_string();

        if url == "/compile" && request.method() == &tiny_http::Method::Post {
            // Read the body
            let mut body = String::new();
            let reader = request.as_reader();
            match reader.read_to_string(&mut body) {
                Ok(_) => {}
                Err(e) => {
                    let resp = tiny_http::Response::from_string(format!("Read error: {e}"))
                        .with_status_code(400);
                    let _ = request.respond(resp);
                    continue;
                }
            }

            let start = Instant::now();
            match inc_compiler.compile(&body) {
                ds_incremental::IncrementalResult::Full(html) => {
                    let ms = start.elapsed().as_millis();
                    println!("   ✅ full compile in {ms}ms ({} bytes)", html.len());
                    let json = format!(r#"{{"type":"full","html":{}}}"#, json_escape(&html));
                    let response = tiny_http::Response::from_string(&json)
                        .with_header(
                            tiny_http::Header::from_bytes(
                                &b"Content-Type"[..],
                                &b"application/json; charset=utf-8"[..],
                            ).unwrap(),
                        )
                        .with_header(
                            tiny_http::Header::from_bytes(
                                &b"Access-Control-Allow-Origin"[..],
                                &b"*"[..],
                            ).unwrap(),
                        );
                    let _ = request.respond(response);
                }
                ds_incremental::IncrementalResult::Patch(js) => {
                    let ms = start.elapsed().as_millis();
                    if js.is_empty() {
                        println!("   ⚡ unchanged ({ms}ms)");
                    } else {
                        println!("   ⚡ incremental patch in {ms}ms ({} bytes)", js.len());
                    }
                    let json = format!(r#"{{"type":"patch","js":{}}}"#, json_escape(&js));
                    let response = tiny_http::Response::from_string(&json)
                        .with_header(
                            tiny_http::Header::from_bytes(
                                &b"Content-Type"[..],
                                &b"application/json; charset=utf-8"[..],
                            ).unwrap(),
                        )
                        .with_header(
                            tiny_http::Header::from_bytes(
                                &b"Access-Control-Allow-Origin"[..],
                                &b"*"[..],
                            ).unwrap(),
                        );
                    let _ = request.respond(response);
                }
                ds_incremental::IncrementalResult::Error(e) => {
                    println!("   ❌ compile error");
                    let json = format!(r#"{{"type":"error","message":{}}}"#, json_escape(&e));
                    let response = tiny_http::Response::from_string(&json)
                        .with_status_code(400)
                        .with_header(
                            tiny_http::Header::from_bytes(
                                &b"Content-Type"[..],
                                &b"application/json; charset=utf-8"[..],
                            ).unwrap(),
                        );
                    let _ = request.respond(response);
                }
            }
        } else {
            // Serve the playground HTML
            let response = tiny_http::Response::from_string(&playground_html)
                .with_header(
                    tiny_http::Header::from_bytes(
                        &b"Content-Type"[..],
                        &b"text/html; charset=utf-8"[..],
                    ).unwrap(),
                );
            let _ = request.respond(response);
        }
    }
}

fn default_playground_source() -> String {
    r#"let count = 0
let label = "Hello, DreamStack!"

on click -> count = count + 1

view main = column [
  text label
  text count
  button "Increment" { click: count += 1 }
]
"#.to_string()
}

/// Escape a string for embedding in JSON.
fn json_escape(s: &str) -> String {
    let mut out = String::with_capacity(s.len() + 2);
    out.push('"');
    for c in s.chars() {
        match c {
            '"' => out.push_str("\\\""),
            '\\' => out.push_str("\\\\"),
            '\n' => out.push_str("\\n"),
            '\r' => out.push_str("\\r"),
            '\t' => out.push_str("\\t"),
            c if c < '\x20' => out.push_str(&format!("\\u{:04x}", c as u32)),
            c => out.push(c),
        }
    }
    out.push('"');
    out
}

// ── Registry: dreamstack add ──

struct RegistryItem {
    name: &'static str,
    description: &'static str,
    source: &'static str,
    deps: &'static [&'static str],
}

const REGISTRY: &[RegistryItem] = &[
    RegistryItem {
        name: "button",
        description: "Styled button with variant support (primary, secondary, ghost, destructive)",
        source: include_str!("../../../registry/components/button.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "input",
        description: "Text input with label, placeholder, and error state",
        source: include_str!("../../../registry/components/input.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "card",
        description: "Content container with title and styled border",
        source: include_str!("../../../registry/components/card.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "badge",
        description: "Status badge with color variants",
        source: include_str!("../../../registry/components/badge.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "dialog",
        description: "Modal dialog with overlay and close button",
        source: include_str!("../../../registry/components/dialog.ds"),
        deps: &["button"],
    },
    RegistryItem {
        name: "toast",
        description: "Notification toast with auto-dismiss",
        source: include_str!("../../../registry/components/toast.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "progress",
        description: "Animated progress bar with percentage",
        source: include_str!("../../../registry/components/progress.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "alert",
        description: "Alert banner with info/warning/error/success variants",
        source: include_str!("../../../registry/components/alert.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "separator",
        description: "Visual divider between content sections",
        source: include_str!("../../../registry/components/separator.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "toggle",
        description: "On/off switch toggle",
        source: include_str!("../../../registry/components/toggle.ds"),
        deps: &[],
    },
    RegistryItem {
        name: "avatar",
        description: "User avatar with initials fallback",
        source: include_str!("../../../registry/components/avatar.ds"),
        deps: &[],
    },
];

fn cmd_add(name: Option<String>, list: bool, all: bool) {
    if list {
        println!("📦 Available DreamStack components:\n");
        for item in REGISTRY {
            let deps = if item.deps.is_empty() {
                String::new()
            } else {
                format!(" (deps: {})", item.deps.join(", "))
            };
            println!("   {} — {}{}", item.name, item.description, deps);
        }
        println!("\n   Use: dreamstack add <name>");
        return;
    }

    let components_dir = Path::new("components");
    if !components_dir.exists() {
        fs::create_dir_all(components_dir).expect("Failed to create components/ directory");
    }

    let names_to_add: Vec<String> = if all {
        REGISTRY.iter().map(|r| r.name.to_string()).collect()
    } else if let Some(name) = name {
        vec![name]
    } else {
        println!("Usage: dreamstack add <component>\n       dreamstack add --list\n       dreamstack add --all");
        return;
    };

    let mut added = std::collections::HashSet::new();
    for name in &names_to_add {
        add_component(name, &components_dir, &mut added);
    }

    if added.is_empty() {
        println!("❌ No components found. Use 'dreamstack add --list' to see available.");
    }
}

fn add_component(name: &str, dest: &Path, added: &mut std::collections::HashSet<String>) {
    if added.contains(name) {
        return;
    }

    let item = match REGISTRY.iter().find(|r| r.name == name) {
        Some(item) => item,
        None => {
            println!("   ❌ Unknown component: {name}");
            return;
        }
    };

    // Add dependencies first
    for dep in item.deps {
        add_component(dep, dest, added);
    }

    let dest_file = dest.join(format!("{}.ds", name));
    // Fix imports: ./button → ./button (relative within components/)
    let source = item.source.replace("from \"./", "from \"./");
    fs::write(&dest_file, source).expect("Failed to write component file");

    let dep_info = if !item.deps.is_empty() {
        " (dependency)"
    } else {
        ""
    };
    println!("   ✅ Added components/{}.ds{}", name, dep_info);
    added.insert(name.to_string());
}

// ── Converter: dreamstack convert ──

fn cmd_convert(name: &str, shadcn: bool, output: Option<&Path>) {
    let tsx_source = if shadcn {
        // Fetch from shadcn/ui GitHub
        let url = format!(
            "https://raw.githubusercontent.com/shadcn-ui/taxonomy/main/components/ui/{}.tsx",
            name
        );
        println!("   📥 Fetching {}.tsx from shadcn/ui...", name);
        match fetch_url_blocking(&url) {
            Ok(source) => source,
            Err(e) => {
                println!("   ❌ Failed to fetch: {e}");
                println!("   Try providing a local .tsx file instead.");
                return;
            }
        }
    } else {
        // Read local file
        match fs::read_to_string(name) {
            Ok(source) => source,
            Err(e) => {
                println!("   ❌ Cannot read '{name}': {e}");
                return;
            }
        }
    };

    let ds_output = convert_tsx_to_ds(&tsx_source, name);

    if let Some(out_path) = output {
        fs::write(out_path, &ds_output).expect("Failed to write output file");
        println!("   ✅ Converted to {}", out_path.display());
    } else {
        println!("{}", ds_output);
    }
}

/// Best-effort TSX → DreamStack converter.
/// Pattern-matches common React/shadcn idioms rather than full TypeScript parsing.
fn convert_tsx_to_ds(tsx: &str, file_hint: &str) -> String {
    let mut out = String::new();

    // Extract component name
    let comp_name = extract_component_name(tsx)
        .unwrap_or_else(|| {
            // Derive from filename
            let base = Path::new(file_hint)
                .file_stem()
                .and_then(|s| s.to_str())
                .unwrap_or("Component");
            let mut chars = base.chars();
            match chars.next() {
                Some(c) => format!("{}{}", c.to_uppercase().collect::<String>(), chars.collect::<String>()),
                None => "Component".to_string(),
            }
        });

    // Extract props
    let props = extract_props(tsx);

    // Header comment
    out.push_str(&format!("-- Converted from {}\n", file_hint));
    out.push_str("-- Auto-generated by dreamstack convert\n\n");

    // Extract useState hooks → let declarations
    let state_vars = extract_use_state(tsx);
    for (name, default) in &state_vars {
        out.push_str(&format!("let {} = {}\n", name, default));
    }
    if !state_vars.is_empty() {
        out.push('\n');
    }

    // Extract cva variants
    let variants = extract_cva_variants(tsx);
    if !variants.is_empty() {
        out.push_str("-- Variants:\n");
        for (variant_name, values) in &variants {
            out.push_str(&format!("--   {}: {}\n", variant_name, values.join(", ")));
        }
        out.push('\n');
    }

    // Extract JSX body
    let jsx_body = extract_jsx_body(tsx);

    // Build component declaration
    let props_str = if props.is_empty() {
        String::new()
    } else {
        format!("({})", props.join(", "))
    };

    out.push_str(&format!("export component {}{} =\n", comp_name, props_str));

    if jsx_body.is_empty() {
        out.push_str("  text \"TODO: convert JSX body\"\n");
    } else {
        out.push_str(&jsx_body);
    }

    out
}

/// Extract component name from React.forwardRef or function/const declaration
fn extract_component_name(tsx: &str) -> Option<String> {
    // Pattern: `const Button = React.forwardRef`
    for line in tsx.lines() {
        let trimmed = line.trim();
        if trimmed.contains("forwardRef") || trimmed.contains("React.forwardRef") {
            if let Some(pos) = trimmed.find("const ") {
                let rest = &trimmed[pos + 6..];
                if let Some(eq_pos) = rest.find(" =") {
                    return Some(rest[..eq_pos].trim().to_string());
                }
            }
        }
        // Pattern: `export function Button(`
        if trimmed.starts_with("export function ") || trimmed.starts_with("function ") {
            let rest = trimmed.strip_prefix("export ").unwrap_or(trimmed);
            let rest = rest.strip_prefix("function ").unwrap_or(rest);
            if let Some(paren) = rest.find('(') {
                let name = rest[..paren].trim();
                if name.chars().next().map_or(false, |c| c.is_uppercase()) {
                    return Some(name.to_string());
                }
            }
        }
    }
    None
}

/// Extract props from destructured function parameters
fn extract_props(tsx: &str) -> Vec<String> {
    let mut props = Vec::new();
    // Look for destructured props: `({ className, variant, size, ...props })`
    if let Some(start) = tsx.find("({ ") {
        if let Some(end) = tsx[start..].find(" })") {
            let inner = &tsx[start + 3..start + end];
            for part in inner.split(',') {
                let part = part.trim();
                if part.starts_with("...") { continue; }  // skip rest props
                if part.is_empty() { continue; }
                // Handle defaults: `variant = "default"` → just `variant`
                let name = part.split('=').next().unwrap_or(part).trim();
                let name = name.split(':').next().unwrap_or(name).trim();
                if !name.is_empty()
                    && name != "className"
                    && name != "ref"
                    && name != "children"
                    && !props.contains(&name.to_string())
                {
                    props.push(name.to_string());
                }
            }
        }
    }
    props
}

/// Extract useState hooks: `const [open, setOpen] = useState(false)` → ("open", "false")
fn extract_use_state(tsx: &str) -> Vec<(String, String)> {
    let mut states = Vec::new();
    for line in tsx.lines() {
        let trimmed = line.trim();
        if trimmed.contains("useState") {
            // const [name, setName] = useState(default)
            if let Some(bracket_start) = trimmed.find('[') {
                if let Some(comma) = trimmed[bracket_start..].find(',') {
                    let name = trimmed[bracket_start + 1..bracket_start + comma].trim();
                    // Extract default value from useState(...)
                    if let Some(paren_start) = trimmed.find("useState(") {
                        let rest = &trimmed[paren_start + 9..];
                        if let Some(paren_end) = rest.find(')') {
                            let default = rest[..paren_end].trim();
                            let ds_default = convert_value(default);
                            states.push((name.to_string(), ds_default));
                        }
                    }
                }
            }
        }
    }
    states
}

/// Extract cva variant definitions
fn extract_cva_variants(tsx: &str) -> Vec<(String, Vec<String>)> {
    let mut variants = Vec::new();
    let mut in_variants = false;
    let mut current_variant = String::new();
    let mut current_values = Vec::new();

    for line in tsx.lines() {
        let trimmed = line.trim();
        if trimmed == "variants: {" {
            in_variants = true;
            continue;
        }
        if in_variants {
            if trimmed == "}," || trimmed == "}" {
                if !current_variant.is_empty() {
                    variants.push((current_variant.clone(), current_values.clone()));
                    current_variant.clear();
                    current_values.clear();
                }
                if trimmed == "}," {
                    // Could be end of a variant group or end of variants
                    if trimmed == "}," { continue; }
                }
                in_variants = false;
                continue;
            }
            // Variant group: `variant: {`
            if trimmed.ends_with(": {") || trimmed.ends_with(":{") {
                if !current_variant.is_empty() {
                    variants.push((current_variant.clone(), current_values.clone()));
                    current_values.clear();
                }
                current_variant = trimmed.split(':').next().unwrap_or("").trim().to_string();
                continue;
            }
            // Variant value: `default: "bg-primary text-primary-foreground",`
            if trimmed.contains(":") && !current_variant.is_empty() {
                let name = trimmed.split(':').next().unwrap_or("").trim().trim_matches('"');
                if !name.is_empty() {
                    current_values.push(name.to_string());
                }
            }
        }
    }
    if !current_variant.is_empty() {
        variants.push((current_variant, current_values));
    }
    variants
}

/// Convert a JSX body to DreamStack view syntax (best-effort)
fn extract_jsx_body(tsx: &str) -> String {
    let mut out = String::new();
    let mut in_return = false;
    let mut depth = 0;

    for line in tsx.lines() {
        let trimmed = line.trim();

        // Find the return statement
        if trimmed.starts_with("return (") || trimmed == "return (" {
            in_return = true;
            depth = 1;
            continue;
        }

        if !in_return { continue; }

        // Track parens
        for c in trimmed.chars() {
            match c {
                '(' => depth += 1,
                ')' => {
                    depth -= 1;
                    if depth <= 0 {
                        in_return = false;
                    }
                }
                _ => {}
            }
        }

        if !in_return && depth <= 0 { break; }

        // Convert JSX elements
        let converted = convert_jsx_line(trimmed);
        if !converted.is_empty() {
            out.push_str("  ");
            out.push_str(&converted);
            out.push('\n');
        }
    }

    out
}

/// Convert a single JSX line to DreamStack syntax
fn convert_jsx_line(jsx: &str) -> String {
    let trimmed = jsx.trim();

    // Skip closing tags
    if trimmed.starts_with("</") { return String::new(); }
    // Skip fragments
    if trimmed == "<>" || trimmed == "</>" { return String::new(); }
    // Skip className-only attributes
    if trimmed.starts_with("className=") { return String::new(); }

    // Self-closing tag: `<Component prop="val" />`
    if trimmed.starts_with('<') && trimmed.ends_with("/>") {
        let inner = &trimmed[1..trimmed.len() - 2].trim();
        let parts: Vec<&str> = inner.splitn(2, ' ').collect();
        let tag = parts[0];
        let ds_tag = convert_html_tag(tag);
        if parts.len() > 1 {
            let attrs = convert_jsx_attrs(parts[1]);
            return format!("{} {{ {} }}", ds_tag, attrs);
        }
        return ds_tag;
    }

    // Opening tag: `<button ... >`
    if trimmed.starts_with('<') && !trimmed.starts_with("</") {
        let close = trimmed.find('>').unwrap_or(trimmed.len());
        let inner = &trimmed[1..close].trim();
        let parts: Vec<&str> = inner.splitn(2, ' ').collect();
        let tag = parts[0];
        let ds_tag = convert_html_tag(tag);

        // Check for text content after >
        if close < trimmed.len() - 1 {
            let content = trimmed[close + 1..].trim();
            let content = content.trim_end_matches(&format!("</{}>", tag));
            if !content.is_empty() {
                return format!("{} \"{}\"", ds_tag, content);
            }
        }

        if parts.len() > 1 {
            let attrs = convert_jsx_attrs(parts[1]);
            return format!("{} {{ {} }}", ds_tag, attrs);
        }
        return ds_tag;
    }

    // JSX expression: `{children}`, `{title}`
    if trimmed.starts_with('{') && trimmed.ends_with('}') {
        let expr = &trimmed[1..trimmed.len() - 1].trim();
        // Conditional: `{condition && <X/>}`
        if expr.contains(" && ") {
            let parts: Vec<&str> = expr.splitn(2, " && ").collect();
            return format!("-- when {} -> ...", parts[0]);
        }
        return format!("text {}", expr);
    }

    // Plain text content
    if !trimmed.is_empty() && !trimmed.starts_with("//") && !trimmed.starts_with("/*") {
        return format!("-- {}", trimmed);
    }

    String::new()
}

/// Convert HTML tag to DreamStack element
fn convert_html_tag(tag: &str) -> String {
    match tag {
        "button" => "button".to_string(),
        "input" => "input".to_string(),
        "div" => "column [".to_string(),
        "span" => "text".to_string(),
        "p" => "text".to_string(),
        "h1" | "h2" | "h3" | "h4" | "h5" | "h6" => "text".to_string(),
        "img" => "image".to_string(),
        "a" => "link".to_string(),
        "label" => "label".to_string(),
        "form" => "column [".to_string(),
        "ul" | "ol" => "column [".to_string(),
        "li" => "text".to_string(),
        // Capitalized = component use
        _ if tag.chars().next().map_or(false, |c| c.is_uppercase()) => {
            format!("{}", tag)
        }
        _ => format!("-- unknown: <{}>", tag),
    }
}

/// Convert JSX attributes to DreamStack props
fn convert_jsx_attrs(attrs: &str) -> String {
    let mut props = Vec::new();
    // Simple: key="value" or key={expr}
    let mut remaining = attrs.trim().trim_end_matches('>').trim_end_matches('/').trim();
    while !remaining.is_empty() {
        // Skip className
        if remaining.starts_with("className=") {
            // Skip to next attr
            if let Some(quote_end) = skip_attr_value(remaining) {
                remaining = remaining[quote_end..].trim();
                continue;
            }
            break;
        }
        // Skip ref
        if remaining.starts_with("ref=") {
            if let Some(quote_end) = skip_attr_value(remaining) {
                remaining = remaining[quote_end..].trim();
                continue;
            }
            break;
        }
        // Skip {...props}
        if remaining.starts_with("{...") {
            if let Some(end) = remaining.find('}') {
                remaining = remaining[end + 1..].trim();
                continue;
            }
            break;
        }

        // Parse key=value
        if let Some(eq_pos) = remaining.find('=') {
            let key = remaining[..eq_pos].trim();
            let rest = remaining[eq_pos + 1..].trim();

            let ds_key = convert_event_name(key);

            if rest.starts_with('"') {
                // String value
                if let Some(end) = rest[1..].find('"') {
                    let val = &rest[1..1 + end];
                    props.push(format!("{}: \"{}\"", ds_key, val));
                    remaining = rest[end + 2..].trim();
                } else {
                    break;
                }
            } else if rest.starts_with('{') {
                // Expression value
                if let Some(end) = find_matching_brace(rest) {
                    let expr = &rest[1..end].trim();
                    props.push(format!("{}: {}", ds_key, expr));
                    remaining = rest[end + 1..].trim();
                } else {
                    break;
                }
            } else {
                break;
            }
        } else {
            break;
        }
    }
    props.join(", ")
}

fn convert_event_name(name: &str) -> String {
    match name {
        "onClick" => "click".to_string(),
        "onChange" => "change".to_string(),
        "onSubmit" => "submit".to_string(),
        "onKeyDown" => "keydown".to_string(),
        "onFocus" => "focus".to_string(),
        "onBlur" => "blur".to_string(),
        "disabled" => "disabled".to_string(),
        "placeholder" => "placeholder".to_string(),
        "type" => "type".to_string(),
        "value" => "value".to_string(),
        "href" => "href".to_string(),
        "src" => "src".to_string(),
        "alt" => "alt".to_string(),
        _ => name.to_string(),
    }
}

fn convert_value(val: &str) -> String {
    match val {
        "true" => "true".to_string(),
        "false" => "false".to_string(),
        "null" | "undefined" => "0".to_string(),
        s if s.starts_with('"') => s.to_string(),
        s if s.starts_with('\'') => format!("\"{}\"", &s[1..s.len()-1]),
        s => s.to_string(),
    }
}

fn skip_attr_value(s: &str) -> Option<usize> {
    let eq = s.find('=')?;
    let rest = &s[eq + 1..];
    if rest.starts_with('"') {
        let end = rest[1..].find('"')?;
        Some(eq + 1 + end + 2)
    } else if rest.starts_with('{') {
        let end = find_matching_brace(rest)?;
        Some(eq + 1 + end + 1)
    } else {
        Some(eq + 1)
    }
}

fn find_matching_brace(s: &str) -> Option<usize> {
    let mut depth = 0;
    for (i, c) in s.chars().enumerate() {
        match c {
            '{' => depth += 1,
            '}' => {
                depth -= 1;
                if depth == 0 { return Some(i); }
            }
            _ => {}
        }
    }
    None
}

/// Simple blocking HTTP fetch (no async runtime needed)
fn fetch_url_blocking(url: &str) -> Result<String, String> {
    // Use std::process to call curl
    let output = std::process::Command::new("curl")
        .args(["-sL", "--fail", url])
        .output()
        .map_err(|e| format!("Failed to run curl: {e}"))?;

    if !output.status.success() {
        return Err(format!("HTTP request failed (status {})", output.status));
    }

    String::from_utf8(output.stdout)
        .map_err(|e| format!("Invalid UTF-8 in response: {e}"))
}