#!/usr/bin/env python3
"""
fleet_api.py — Lightweight HTTP API for the shared fleet palace.

Exposes fleet memory search over HTTP so that Alpha servers and other
wizard deployments can query the palace without direct filesystem access.

Endpoints:
    GET /health
        Returns {"status": "ok", "palace": "<path>"}

    GET /search?q=<query>[&room=<room>][&n=<int>]
        Returns {"results": [...], "query": "...", "room": "...", "count": N}
        Each result: {"text": "...", "room": "...", "wing": "...", "score": 0.9}

    GET /wings
        Returns {"wings": ["bezalel", ...]} — distinct wizard wings present

Error responses use {"error": "<message>"} with appropriate HTTP status codes.

Usage:
    # Default: localhost:7771, fleet palace at /var/lib/mempalace/fleet
    python mempalace/fleet_api.py

    # Custom host/port/palace:
    FLEET_PALACE_PATH=/data/fleet python mempalace/fleet_api.py --host 0.0.0.0 --port 8080

Refs: #1078, #1075
"""

from __future__ import annotations

import argparse
import json
import os
import sys
from http.server import BaseHTTPRequestHandler, HTTPServer
from pathlib import Path
from urllib.parse import parse_qs, urlparse

# Add repo root to path so we can import nexus.mempalace
_HERE = Path(__file__).resolve().parent
_REPO_ROOT = _HERE.parent
if str(_REPO_ROOT) not in sys.path:
    sys.path.insert(0, str(_REPO_ROOT))

DEFAULT_HOST = "127.0.0.1"
DEFAULT_PORT = 7771
MAX_RESULTS = 50


def _get_palace_path() -> Path:
    return Path(os.environ.get("FLEET_PALACE_PATH", "/var/lib/mempalace/fleet"))


def _json_response(handler: BaseHTTPRequestHandler, status: int, body: dict) -> None:
    payload = json.dumps(body).encode()
    handler.send_response(status)
    handler.send_header("Content-Type", "application/json")
    handler.send_header("Content-Length", str(len(payload)))
    handler.end_headers()
    handler.wfile.write(payload)


def _handle_health(handler: BaseHTTPRequestHandler) -> None:
    palace = _get_palace_path()
    _json_response(handler, 200, {
        "status": "ok",
        "palace": str(palace),
        "palace_exists": palace.exists(),
    })


def _handle_search(handler: BaseHTTPRequestHandler, qs: dict) -> None:
    query_terms = qs.get("q", [""])
    q = query_terms[0].strip() if query_terms else ""
    if not q:
        _json_response(handler, 400, {"error": "Missing required parameter: q"})
        return

    room_terms = qs.get("room", [])
    room = room_terms[0].strip() if room_terms else None

    n_terms = qs.get("n", [])
    try:
        n = max(1, min(int(n_terms[0]), MAX_RESULTS)) if n_terms else 10
    except (ValueError, IndexError):
        _json_response(handler, 400, {"error": "Invalid parameter: n must be an integer"})
        return

    try:
        from nexus.mempalace.searcher import search_fleet, MemPalaceUnavailable
    except ImportError as exc:
        _json_response(handler, 503, {"error": f"MemPalace module not available: {exc}"})
        return

    try:
        results = search_fleet(q, room=room, n_results=n)
    except Exception as exc:  # noqa: BLE001
        _json_response(handler, 503, {"error": str(exc)})
        return

    _json_response(handler, 200, {
        "query": q,
        "room": room,
        "count": len(results),
        "results": [
            {
                "text": r.text,
                "room": r.room,
                "wing": r.wing,
                "score": round(r.score, 4),
            }
            for r in results
        ],
    })


def _handle_wings(handler: BaseHTTPRequestHandler) -> None:
    """Return distinct wizard wing names found in the fleet palace directory."""
    palace = _get_palace_path()
    if not palace.exists():
        _json_response(handler, 503, {
            "error": f"Fleet palace not found: {palace}",
        })
        return

    wings = sorted({
        p.name for p in palace.iterdir() if p.is_dir()
    })
    _json_response(handler, 200, {"wings": wings})


class FleetAPIHandler(BaseHTTPRequestHandler):
    """Request handler for the fleet memory API."""

    def log_message(self, fmt: str, *args) -> None:  # noqa: ANN001
        # Prefix with tag for easier log filtering
        sys.stderr.write(f"[fleet_api] {fmt % args}\n")

    def do_GET(self) -> None:  # noqa: N802
        parsed = urlparse(self.path)
        path = parsed.path.rstrip("/") or "/"
        qs = parse_qs(parsed.query)

        if path == "/health":
            _handle_health(self)
        elif path == "/search":
            _handle_search(self, qs)
        elif path == "/wings":
            _handle_wings(self)
        else:
            _json_response(self, 404, {
                "error": f"Unknown endpoint: {path}",
                "endpoints": ["/health", "/search", "/wings"],
            })


def make_server(host: str = DEFAULT_HOST, port: int = DEFAULT_PORT) -> HTTPServer:
    return HTTPServer((host, port), FleetAPIHandler)


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(
        description="Fleet palace HTTP API server."
    )
    parser.add_argument("--host", default=DEFAULT_HOST, help=f"Bind host (default: {DEFAULT_HOST})")
    parser.add_argument("--port", type=int, default=DEFAULT_PORT, help=f"Bind port (default: {DEFAULT_PORT})")
    args = parser.parse_args(argv)

    palace = _get_palace_path()
    print(f"[fleet_api] Palace: {palace}")
    if not palace.exists():
        print(f"[fleet_api] WARNING: palace path does not exist yet: {palace}", file=sys.stderr)

    server = make_server(args.host, args.port)
    print(f"[fleet_api] Listening on http://{args.host}:{args.port}")
    try:
        server.serve_forever()
    except KeyboardInterrupt:
        print("\n[fleet_api] Shutting down.")
    return 0


if __name__ == "__main__":
    sys.exit(main())