#!/usr/bin/env python3
"""
ASW Dev Server — http.server with ASW-styled error pages.

Drop this in any directory and run it instead of `python -m http.server`.
All error responses (403, 404, 500, etc.) are styled with ASW CSS.

Usage:
    python asw_server.py              # serve on port 8000
    python asw_server.py 3000         # custom port
    python asw_server.py 3000 /dir    # custom port + directory

The server inlines ASW styles so no external dependencies are needed.
"""

import http.server
import sys
import os
import socket
import urllib.parse
import html


# ── Minimal ASW inline styles ─────────────────────────────────────────────────
# Reduced version for standalone error pages — no external deps.

ASW_INLINE = """
  :root {
    --asw-bg: #0d1117;
    --asw-bg-elevated: #161b22;
    --asw-bg-overlay: #1c2128;
    --asw-text: #e6edf3;
    --asw-text-secondary: #8b949e;
    --asw-text-muted: #484f58;
    --asw-accent: #3fb950;
    --asw-border: #30363d;
    --asw-font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    --asw-font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', ui-monospace, monospace;
  }
  *, *::before, *::after { box-sizing: border-box; }
  html { font-size: 16px; }
  body {
    background: var(--asw-bg);
    color: var(--asw-text);
    font-family: var(--asw-font-body);
    font-size: 1rem;
    line-height: 1.6;
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
  }
  nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.5rem;
    border-bottom: 1px solid var(--asw-border);
    background: var(--asw-bg-elevated);
  }
  nav a { color: var(--asw-text); text-decoration: none; font-weight: 600; }
  nav a:hover { color: var(--asw-accent); }
  .badge {
    font-family: var(--asw-font-mono);
    font-size: 0.75rem;
    color: var(--asw-text-muted);
    background: var(--asw-bg-overlay);
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    border: 1px solid var(--asw-border);
  }
  main {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
  }
  .error-card {
    max-width: 42ch;
    text-align: center;
  }
  .error-code {
    font-family: var(--asw-font-mono);
    font-size: 6rem;
    font-weight: 700;
    line-height: 1;
    color: var(--asw-text-muted);
    letter-spacing: -0.05em;
    margin: 0 0 0.5rem;
  }
  h1 {
    margin: 0 0 1rem;
    font-size: 1.5rem;
    color: var(--asw-text);
  }
  p { margin: 0 0 0.75rem; color: var(--asw-text-secondary); }
  a.button {
    display: inline-block;
    margin-top: 1.5rem;
    padding: 0.5rem 1.25rem;
    background: transparent;
    color: var(--asw-accent);
    border: 1px solid var(--asw-accent);
    border-radius: 0.375rem;
    text-decoration: none;
    font-size: 0.875rem;
    transition: background 0.15s;
  }
  a.button:hover { background: rgba(63, 185, 80, 0.1); }
  code {
    font-family: var(--asw-font-mono);
    font-size: 0.85em;
    background: var(--asw-bg-overlay);
    padding: 0.1em 0.35em;
    border-radius: 0.2rem;
    color: var(--asw-text-secondary);
  }
  footer {
    text-align: center;
    padding: 1rem;
    font-size: 0.75rem;
    color: var(--asw-text-muted);
    border-top: 1px solid var(--asw-border);
  }
  footer a { color: var(--asw-text-muted); }

  /* Directory listing */
  .dir-listing { max-width: 72ch; width: 100%; }
  .dir-listing h1 { font-size: 1.25rem; margin-bottom: 1.5rem; text-align: left; }
  .dir-listing h1 code { font-size: 1rem; }
  table { width: 100%; border-collapse: collapse; }
  th, td { padding: 0.5rem 0.75rem; text-align: left; border-bottom: 1px solid var(--asw-border); }
  th { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--asw-text-muted); }
  td a { color: var(--asw-accent); text-decoration: none; }
  td a:hover { text-decoration: underline; }
  .size { color: var(--asw-text-muted); font-family: var(--asw-font-mono); font-size: 0.8rem; }
  .parent { color: var(--asw-text-muted); }
"""


ERROR_MESSAGES = {
    400: ("Bad Request",         "The server couldn't understand the request."),
    401: ("Unauthorized",        "Authentication is required to access this resource."),
    403: ("Forbidden",           "You don't have permission to access this path."),
    404: ("Not Found",           "The file or directory you requested doesn't exist."),
    405: ("Method Not Allowed",  "That HTTP method isn't supported here."),
    408: ("Request Timeout",     "The request took too long to process."),
    500: ("Server Error",        "Something went wrong on the server."),
    501: ("Not Implemented",     "The server doesn't support that feature."),
    503: ("Service Unavailable", "The server is temporarily unable to handle requests."),
}


def error_page(code: int, path: str = "") -> bytes:
    title, message = ERROR_MESSAGES.get(code, ("Error", "An error occurred."))
    path_hint = f"<p>Path: <code>{html.escape(path)}</code></p>" if path else ""
    body = f"""<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>{code} — {title}</title>
  <style>{ASW_INLINE}</style>
</head>
<body>
  <nav>
    <a href="/">&#x2302; Dev Server</a>
    <span class="badge">http.server</span>
  </nav>
  <main>
    <div class="error-card">
      <p class="error-code">{code}</p>
      <h1>{title}</h1>
      <p>{message}</p>
      {path_hint}
      <a class="button" href="/">← Back to root</a>
    </div>
  </main>
  <footer>ASW Dev Server &middot; <a href="https://github.com/trentuna/agentic-semantic-web">agentic-semantic-web</a></footer>
</body>
</html>"""
    return body.encode("utf-8")


def dir_listing_page(path: str, display_path: str, entries: list) -> bytes:
    rows = []
    if display_path != "/":
        parent = "/" + "/".join(display_path.strip("/").split("/")[:-1])
        rows.append(f'<tr><td class="parent"><a href="{parent or "/"}">../</a></td><td class="size">—</td></tr>')

    for name, is_dir, size in sorted(entries, key=lambda e: (not e[1], e[0].lower())):
        link_name = html.escape(name) + ("/" if is_dir else "")
        href = urllib.parse.quote(name) + ("/" if is_dir else "")
        size_str = "—" if is_dir else _human_size(size)
        rows.append(f'<tr><td><a href="{href}">{link_name}</a></td><td class="size">{size_str}</td></tr>')

    rows_html = "\n      ".join(rows)
    body = f"""<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Index of {html.escape(display_path)}</title>
  <style>{ASW_INLINE}</style>
</head>
<body>
  <nav>
    <a href="/">&#x2302; Dev Server</a>
    <span class="badge">http.server</span>
  </nav>
  <main>
    <div class="dir-listing">
      <h1>Index of <code>{html.escape(display_path)}</code></h1>
      <table>
        <thead><tr><th>Name</th><th>Size</th></tr></thead>
        <tbody>
      {rows_html}
        </tbody>
      </table>
    </div>
  </main>
  <footer>ASW Dev Server &middot; <a href="https://github.com/trentuna/agentic-semantic-web">agentic-semantic-web</a></footer>
</body>
</html>"""
    return body.encode("utf-8")


def _human_size(n: int) -> str:
    for unit in ("B", "KB", "MB", "GB"):
        if n < 1024:
            return f"{n:.0f} {unit}" if unit == "B" else f"{n:.1f} {unit}"
        n /= 1024
    return f"{n:.1f} TB"


class ASWHandler(http.server.SimpleHTTPRequestHandler):
    """SimpleHTTPRequestHandler with ASW-styled error pages and directory listings."""

    server_version = "ASWServer/1.0"

    def send_error(self, code, message=None, explain=None):
        """Override to send ASW-styled error pages."""
        try:
            short, long = self.responses[code]
        except KeyError:
            short, long = "???", "???"
        if message is None:
            message = short
        if explain is None:
            explain = long

        # Log to terminal
        self.log_error("code %d, message %s", code, message)

        # Build ASW error page
        path = getattr(self, "path", "")
        content = error_page(code, path)

        self.send_response(code, message)
        self.send_header("Content-Type", "text/html; charset=utf-8")
        self.send_header("Content-Length", str(len(content)))
        self.send_header("Connection", "close")
        self.end_headers()
        if self.command != "HEAD" and code >= 200 and code not in (204, 304):
            self.wfile.write(content)

    def list_directory(self, path):
        """Override to send ASW-styled directory listing."""
        try:
            names = os.listdir(path)
        except OSError:
            self.send_error(403, "No permission to list directory")
            return None

        display_path = urllib.parse.unquote(self.path)
        entries = []
        for name in names:
            full = os.path.join(path, name)
            is_dir = os.path.isdir(full)
            size = 0
            if not is_dir:
                try:
                    size = os.path.getsize(full)
                except OSError:
                    pass
            entries.append((name, is_dir, size))

        content = dir_listing_page(path, display_path, entries)
        self.send_response(200)
        self.send_header("Content-Type", "text/html; charset=utf-8")
        self.send_header("Content-Length", str(len(content)))
        self.end_headers()
        self.wfile.write(content)
        return None

    def log_message(self, fmt, *args):
        """Slightly cleaner terminal output."""
        print(f"  {self.address_string()} — {fmt % args}")


def main():
    port = 8000
    directory = "."

    if len(sys.argv) > 1:
        try:
            port = int(sys.argv[1])
        except ValueError:
            print(f"Usage: {sys.argv[0]} [port] [directory]", file=sys.stderr)
            sys.exit(1)

    if len(sys.argv) > 2:
        directory = sys.argv[2]

    directory = os.path.abspath(directory)

    handler = lambda *args, **kwargs: ASWHandler(*args, directory=directory, **kwargs)

    # Find a free port if needed (dev convenience)
    for attempt in range(10):
        try:
            server = http.server.HTTPServer(("", port + attempt), handler)
            actual_port = port + attempt
            break
        except OSError:
            if attempt == 9:
                print(f"Could not bind to ports {port}–{port+9}", file=sys.stderr)
                sys.exit(1)

    hostname = socket.gethostname()
    print(f"\n  ASW Dev Server")
    print(f"  ──────────────────────────────────")
    print(f"  Serving: {directory}")
    print(f"  Local:   http://localhost:{actual_port}")
    print(f"  Network: http://{hostname}:{actual_port}")
    print(f"  ──────────────────────────────────")
    print(f"  Press Ctrl+C to stop\n")

    try:
        server.serve_forever()
    except KeyboardInterrupt:
        print("\n  Stopped.")
        server.server_close()


if __name__ == "__main__":
    main()