"""Todo API server - lightweight todo management for nav page.
Runs on port 9001, managed by Caddy proxy at /api/todos/*
"""
import json
import os
import uuid
from datetime import datetime, timezone, timedelta
from http.server import HTTPServer, BaseHTTPRequestHandler

TODOS_FILE = "/var/www/nav/data/todos.json"
tz = timezone(timedelta(hours=8))


def load_todos():
    if os.path.exists(TODOS_FILE):
        with open(TODOS_FILE) as f:
            return json.load(f)
    return []


def save_todos(todos):
    os.makedirs(os.path.dirname(TODOS_FILE), exist_ok=True)
    with open(TODOS_FILE, "w") as f:
        json.dump(todos, f, ensure_ascii=False, indent=2)


class TodoHandler(BaseHTTPRequestHandler):
    def _send(self, data, status=200):
        self.send_response(status)
        self.send_header("Content-Type", "application/json; charset=utf-8")
        self.send_header("Access-Control-Allow-Origin", "*")
        self.send_header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
        self.send_header("Access-Control-Allow-Headers", "Content-Type")
        self.end_headers()
        self.wfile.write(json.dumps(data, ensure_ascii=False).encode("utf-8"))

    def do_OPTIONS(self):
        self._send({})

    def do_GET(self):
        if self.path == "/api/todos":
            todos = load_todos()
            self._send({"todos": todos})
        else:
            self._send({"error": "not found"}, 404)

    def do_POST(self):
        if self.path == "/api/todos":
            length = int(self.headers.get("Content-Length", 0))
            body = json.loads(self.rfile.read(length).decode("utf-8"))
            todos = load_todos()
            now = datetime.now(tz).strftime("%Y-%m-%d %H:%M")
            todo = {
                "id": str(uuid.uuid4())[:8],
                "text": body.get("text", ""),
                "done": False,
                "source": body.get("source", "manual"),
                "priority": body.get("priority", "medium"),
                "created_at": now,
            }
            todos.insert(0, todo)
            save_todos(todos)
            self._send({"todo": todo}, 201)
        else:
            self._send({"error": "not found"}, 404)

    def do_PUT(self):
        parts = self.path.split("/")
        if len(parts) == 4 and parts[1] == "api" and parts[2] == "todos":
            tid = parts[3]
            length = int(self.headers.get("Content-Length", 0))
            body = json.loads(self.rfile.read(length).decode("utf-8"))
            todos = load_todos()
            for t in todos:
                if t["id"] == tid:
                    if "done" in body:
                        t["done"] = body["done"]
                    if "text" in body:
                        t["text"] = body["text"]
                    save_todos(todos)
                    self._send({"todo": t})
                    return
            self._send({"error": "not found"}, 404)
        else:
            self._send({"error": "not found"}, 404)

    def do_DELETE(self):
        parts = self.path.split("/")
        if len(parts) == 4 and parts[1] == "api" and parts[2] == "todos":
            tid = parts[3]
            todos = load_todos()
            todos = [t for t in todos if t["id"] != tid]
            save_todos(todos)
            self._send({"deleted": tid})
        else:
            self._send({"error": "not found"}, 404)

    def log_message(self, format, *args):
        pass  # quiet


if __name__ == "__main__":
    port = int(os.environ.get("PORT", 9001))
    server = HTTPServer(("127.0.0.1", port), TodoHandler)
    print(f"Todo API running on :{port}")
    server.serve_forever()