"""
Platform Gateway — Auth handlers (login, logout, register).
"""

"""
NOTE: Passwords are hashed with bcrypt. Any existing SHA-256 hashed passwords
in the database will no longer work. The admin user is re-seeded on first boot
if no users exist. Other users need manual password reset.
"""
import json
import sqlite3

import bcrypt

from database import get_db
from sessions import create_session, delete_session


def handle_login(handler, body):
    try:
        data = json.loads(body)
    except Exception as e:
        handler._send_json({"error": "Invalid JSON"}, 400)
        return

    username = data.get("username", "").strip().lower()
    password = data.get("password", "")

    if not username or not password:
        handler._send_json({"error": "Username and password required"}, 400)
        return

    conn = get_db()
    user = conn.execute("SELECT * FROM users WHERE username = ?",
                        (username,)).fetchone()
    conn.close()

    if not user or not bcrypt.checkpw(password.encode(), user["password_hash"].encode()):
        handler._send_json({"error": "Invalid credentials"}, 401)
        return

    token = create_session(user["id"])

    handler.send_response(200)
    handler.send_header("Content-Type", "application/json")
    handler._set_session_cookie(token)
    resp = json.dumps({
        "success": True,
        "user": {"id": user["id"], "username": user["username"], "display_name": user["display_name"]}
    }).encode()
    handler.send_header("Content-Length", len(resp))
    handler.end_headers()
    handler.wfile.write(resp)


def handle_logout(handler):
    token = handler._get_session_token()
    delete_session(token)
    handler.send_response(200)
    handler.send_header("Content-Type", "application/json")
    handler.send_header("Set-Cookie", "platform_session=; Path=/; HttpOnly; Secure; SameSite=Lax; Max-Age=0")
    resp = b'{"success": true}'
    handler.send_header("Content-Length", len(resp))
    handler.end_headers()
    handler.wfile.write(resp)


def handle_register(handler, body):
    try:
        data = json.loads(body)
    except Exception as e:
        handler._send_json({"error": "Invalid JSON"}, 400)
        return

    username = data.get("username", "").strip().lower()
    password = data.get("password", "")
    display_name = data.get("display_name", username)

    if not username or not password:
        handler._send_json({"error": "Username and password required"}, 400)
        return

    pw_hash = bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()

    conn = get_db()
    try:
        conn.execute("INSERT INTO users (username, password_hash, display_name) VALUES (?, ?, ?)",
                     (username, pw_hash, display_name))
        conn.commit()
        user_id = conn.execute("SELECT id FROM users WHERE username = ?", (username,)).fetchone()["id"]
        conn.close()
        handler._send_json({"success": True, "user_id": user_id})
    except sqlite3.IntegrityError:
        conn.close()
        handler._send_json({"error": "Username already exists"}, 409)