"""One-click start: optional Gemma vLLM (≤15GB), then LAN UI + browser."""

from __future__ import annotations

import os
import shutil
import socket
import subprocess
import sys
import time
import urllib.error
import urllib.request
import webbrowser
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
HOST = "127.0.0.1"
PORT = int(os.environ.get("RECEIPT_UI_PORT", "7860"))
VLLM_PORT = int(os.environ.get("RECEIPT_VLLM_PORT", "8080"))
START_VLLM = os.environ.get("RECEIPT_START_VLLM", "1").lower() not in {"0", "false", "no"}
MAX_GB = os.environ.get("RECEIPT_VLLM_MAX_GB", "15")  # unused if UTIL is set in serve-gemma.sh


def _lan_ip() -> str:
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    try:
        sock.connect(("192.0.2.1", 1))
        return sock.getsockname()[0]
    except OSError:
        return "127.0.0.1"
    finally:
        sock.close()


def _port_up(port: int) -> bool:
    sock = socket.socket()
    sock.settimeout(0.4)
    try:
        sock.connect((HOST, port))
        return True
    except OSError:
        return False
    finally:
        sock.close()


def _vllm_ready() -> bool:
    try:
        with urllib.request.urlopen(
            f"http://127.0.0.1:{VLLM_PORT}/v1/models", timeout=2
        ) as response:
            return response.status == 200
    except (urllib.error.URLError, TimeoutError, OSError):
        return False


def _can_serve_gemma() -> bool:
    if shutil.which("vllm") is None:
        return False
    model = Path(os.environ.get("RECEIPT_GEMMA_PATH", str(Path.home() / "models-gemma4-12b-it")))
    return (model / "config.json").is_file()


def _spawn(cmd: list[str], log: Path, *, bash: bool = False) -> None:
    log.parent.mkdir(parents=True, exist_ok=True)
    creation = 0
    if sys.platform == "win32":
        creation = getattr(subprocess, "CREATE_NEW_CONSOLE", 0)
    argv = cmd
    if bash:
        argv = ["bash", *cmd]
    with log.open("a", encoding="utf-8") as handle:
        subprocess.Popen(
            argv,
            cwd=str(ROOT),
            env=os.environ.copy(),
            stdout=handle,
            stderr=handle,
            creationflags=creation,
            start_new_session=sys.platform != "win32",
        )


def _ensure_vllm() -> None:
    if not START_VLLM:
        return
    if _vllm_ready():
        print(f"Gemma already up on :{VLLM_PORT} (not restarted; 15GB cap applies on a fresh serve).")
        return
    if not _can_serve_gemma():
        print("No local vLLM/Gemma — skip serve. Point .env at the GPU box.")
        return
    script = ROOT / "scripts" / "serve-gemma.sh"
    if not script.is_file():
        print(f"missing {script}", file=sys.stderr)
        return
    os.environ.setdefault("RECEIPT_VLLM_MAX_GB", MAX_GB)
    print("Starting Gemma 4 12B vLLM at gpu_memory_utilization=0.15 (FP8, max-model-len 8192)…")
    _spawn([str(script)], ROOT / "data" / "vllm-gemma.log", bash=True)
    for _ in range(120):
        if _vllm_ready():
            print("Gemma ready.")
            return
        time.sleep(5)
    print(
        f"vLLM still starting. Watch {ROOT / 'data' / 'vllm-gemma.log'}",
        file=sys.stderr,
    )


def _spawn_ui() -> None:
    env = os.environ.copy()
    env["RECEIPT_UI_SHARE_LAN"] = "true"
    env.setdefault("RECEIPT_IDLE_SECONDS", "5")
    log = ROOT / "data" / "ui.log"
    log.parent.mkdir(parents=True, exist_ok=True)
    creation = 0
    if sys.platform == "win32":
        creation = getattr(subprocess, "CREATE_NEW_CONSOLE", 0)
    with log.open("a", encoding="utf-8") as handle:
        subprocess.Popen(
            [sys.executable, "-m", "app.cli", "ui"],
            cwd=str(ROOT),
            env=env,
            stdout=handle,
            stderr=handle,
            creationflags=creation,
            start_new_session=sys.platform != "win32",
        )


def main() -> None:
    os.chdir(ROOT)
    _ensure_vllm()
    if not _port_up(PORT):
        print("Starting Receipt Studio UI…")
        _spawn_ui()
        for _ in range(40):
            if _port_up(PORT):
                break
            time.sleep(0.25)
        else:
            print(f"UI did not bind :{PORT}. See {ROOT / 'data' / 'ui.log'}", file=sys.stderr)
            raise SystemExit(1)
    lan = _lan_ip()
    review = f"http://127.0.0.1:{PORT}"
    phone = f"http://{lan}:{PORT}/phone"
    print(f"Review: {review}")
    print(f"Phone:  {phone}")
    webbrowser.open(review)


if __name__ == "__main__":
    main()