#!/usr/bin/env python3
"""
Simple TCP test server for led-controller.

Listens on the same TCP port used by led-driver WiFi transport and
every 5 seconds sends a newline-delimited JSON message with v="1".

Clients talking to the real Pi registry should send a first line JSON object
that includes device_name and mac (12 hex) so the controller can register
the device by MAC.
"""

import asyncio
import contextlib
import json
import os
import sys
from typing import Dict, Set


CLIENTS: Set[asyncio.StreamWriter] = set()
# Map each client writer to the device_name it reported.
CLIENT_DEVICE: Dict[asyncio.StreamWriter, str] = {}


async def _send_off_to_all():
    """Best-effort send an 'off' message to all connected devices."""
    if not CLIENTS:
        return
    print("[TCP TEST] Sending 'off' to all clients before shutdown")
    dead = []
    for w in CLIENTS:
        device_name = CLIENT_DEVICE.get(w)
        if not device_name:
            continue
        payload = {
            "v": "1",
            "select": {device_name: ["off"]},
        }
        line = json.dumps(payload) + "\n"
        data = line.encode("utf-8")
        try:
            w.write(data)
            await w.drain()
        except Exception as e:
            peer = w.get_extra_info("peername")
            print(f"[TCP TEST] Error sending 'off' to {peer}: {e}")
            dead.append(w)
    for w in dead:
        CLIENTS.discard(w)
        CLIENT_DEVICE.pop(w, None)


async def handle_client(reader: asyncio.StreamReader, writer: asyncio.StreamWriter):
    peer = writer.get_extra_info("peername")
    print(f"[TCP TEST] Client connected: {peer}")
    CLIENTS.add(writer)
    buf = b""
    try:
        # Wait for client to send its device_name JSON, then send presets once.
        sent_presets = False
        while True:
            data = await reader.read(100)
            if not data:
                break
            buf += data
            print(f"[TCP TEST] From client {peer}: {data!r}")

            # Handle newline-delimited JSON from client.
            while b"\n" in buf:
                line, buf = buf.split(b"\n", 1)
                line = line.strip()
                if not line:
                    continue
                try:
                    msg = json.loads(line.decode("utf-8"))
                except Exception:
                    continue

                if isinstance(msg, dict) and "device_name" in msg:
                    device_name = str(msg.get("device_name") or "")
                    CLIENT_DEVICE[writer] = device_name
                    print(f"[TCP TEST] Registered device_name {device_name!r} for {peer}")

                    if not sent_presets and device_name:
                        hello_payload = {
                            "v": "1",
                            "presets": {
                                "solid_red": {
                                    "p": "on",
                                    "c": ["#ff0000"],
                                    "d": 100,
                                },
                                "solid_blue": {
                                    "p": "on",
                                    "c": ["#0000ff"],
                                    "d": 100,
                                },
                            },
                            "select": {
                                device_name: ["solid_red"],
                            },
                            "b": 32,
                        }
                        try:
                            writer.write((json.dumps(hello_payload) + "\n").encode("utf-8"))
                            await writer.drain()
                            sent_presets = True
                            print(
                                f"[TCP TEST] Sent initial presets/select for device "
                                f"{device_name!r} to {peer}"
                            )
                        except Exception as e:
                            print(f"[TCP TEST] Failed to send initial presets/select to {peer}: {e}")
    except Exception as e:
        print(f"[TCP TEST] Client error: {peer} {e}")
    finally:
        print(f"[TCP TEST] Client disconnected: {peer}")
        CLIENTS.discard(writer)
        CLIENT_DEVICE.pop(writer, None)
        try:
            writer.close()
            await writer.wait_closed()
        except Exception:
            pass


async def broadcaster(port: int):
    """Broadcast preset selection / brightness changes every 5 seconds."""
    counter = 0
    while True:
        await asyncio.sleep(5)
        counter += 1

        # Toggle between two presets and brightness levels.
        if CLIENTS:
            print(f"[TCP TEST] Broadcasting to {len(CLIENTS)} client(s)")

        dead = []
        for w in CLIENTS:
            device_name = CLIENT_DEVICE.get(w)
            if not device_name:
                continue

            if counter % 2 == 0:
                preset_name = "solid_red"
                payload = {
                    "v": "1",
                    "select": {device_name: [preset_name]},
                }
            else:
                preset_name = "solid_blue"
                payload = {
                    "v": "1",
                    "select": {device_name: [preset_name]},
                }

            line = json.dumps(payload) + "\n"
            data = line.encode("utf-8")

            try:
                w.write(data)
                await w.drain()
                peer = w.get_extra_info("peername")
                print(
                    f"[TCP TEST] Sent preset {preset_name!r} to device {device_name!r} "
                    f"for client {peer}"
                )
            except Exception as e:
                peer = w.get_extra_info("peername")
                print(f"[TCP TEST] Error writing to {peer}: {e}")
                dead.append(w)

        for w in dead:
            CLIENTS.discard(w)
            CLIENT_DEVICE.pop(w, None)


async def main():
    port = int(os.environ.get("PORT", os.environ.get("TCP_PORT", "8765")))
    host = "0.0.0.0"
    print(f"[TCP TEST] Starting TCP test server on {host}:{port}")

    try:
        server = await asyncio.start_server(handle_client, host=host, port=port)
    except OSError as e:
        if e.errno == 98:  # EADDRINUSE
            print(
                f"[TCP TEST] Port {port} is already in use.\n"
                f"  If led-controller.service is enabled, it binds this port for ESP TCP "
                f"transport after boot. Stop it for a standalone mock:\n"
                f"    sudo systemctl stop led-controller\n"
                f"  Or keep the main app and use another port for this mock:\n"
                f"    TCP_PORT=8766 pipenv run tcp-test\n"
                f"  (point test clients at that port). See also: sudo ss -tlnp | grep {port}",
                file=sys.stderr,
            )
        raise
    async with server:
        broadcaster_task = asyncio.create_task(broadcaster(port))
        try:
            await server.serve_forever()
        finally:
            # On shutdown, try to turn all connected devices off.
            await _send_off_to_all()
            broadcaster_task.cancel()
            with contextlib.suppress(Exception):
                await broadcaster_task


if __name__ == "__main__":
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        print("\n[TCP TEST] Shutting down.")