from __future__ import annotations

import html
import re
import os
import shutil
import subprocess
import asyncio
import sys
from pathlib import Path
import logging
import importlib.util
from dataclasses import dataclass
from itertools import zip_longest
from typing import Iterable


# Version and environment constraints for a "green" health check in the demo.
MIN_DENO_VERSION = (2, 0, 0)
MIN_YTDLP_VERSION = (2025, 11, 12)
MIN_FFMPEG_VERSION = (4, 0)
GEMINI_ENV_VAR = "GEMINI_API_KEY"


@dataclass
class ToolStatus:
    label: str
    ok: bool
    detail: str


@dataclass
class HealthReport:
    ok: bool
    summary: str
    tools: list[ToolStatus]


def _split_version(raw: str) -> Iterable[int]:
    return tuple(int(part) for part in re.findall(r"\d+", raw))


def _version_at_least(raw: str, expected: tuple[int, ...]) -> bool:
    parsed = _split_version(raw)
    if not parsed:
        return False
    for current, required in zip_longest(parsed, expected, fillvalue=0):
        if current > required:
            return True
        if current < required:
            return False
    return True


def _check_deno() -> ToolStatus:
    label = "Deno"
    binary = shutil.which("deno")
    if not binary:
        return ToolStatus(label, False, "`deno` command not found on PATH")
    try:
        completed = subprocess.run(
            [binary, "--version"],
            check=False,
            capture_output=True,
            text=True,
            timeout=10,
        )
    except (FileNotFoundError, subprocess.SubprocessError, OSError) as exc:
        return ToolStatus(label, False, f"Unable to execute: {exc}")
    if completed.returncode != 0:
        detail = completed.stderr.strip() or completed.stdout.strip() or "Unknown error"
        return ToolStatus(label, False, detail)
    match = re.search(r"deno\s+([0-9.]+)", completed.stdout)
    if not match:
        return ToolStatus(label, False, "Could not parse version output")
    version = match.group(1)
    if not _version_at_least(version, MIN_DENO_VERSION):
        return ToolStatus(label, False, f"Found v{version}; need ≥ {'.'.join(map(str, MIN_DENO_VERSION))}")
    return ToolStatus(label, True, f"v{version} ready for yt-dlp")


def _check_yt_dlp_python() -> ToolStatus:
    label = "yt-dlp"
    try:
        import yt_dlp
        from yt_dlp import YoutubeDL
        from yt_dlp.version import __version__ as version_str
    except Exception as exc:
        return ToolStatus(label, False, f"Import failed: {exc}")

    try:
        with YoutubeDL(params={"skip_download": True, "quiet": True}) as ydl:
            _ = ydl.params.get("skip_download")
    except Exception as exc:
        return ToolStatus(label, False, f"YoutubeDL bootstrap failed: {exc}")

    if not _version_at_least(version_str, MIN_YTDLP_VERSION):
        minimum = ".".join(map(str, MIN_YTDLP_VERSION))
        return ToolStatus(label, False, f"Detected {version_str}; require ≥ {minimum}")

    has_ejs = importlib.util.find_spec("yt_dlp_ejs") is not None
    if has_ejs:
        return ToolStatus(label, True, f"v{version_str}")
    return ToolStatus(label, False, "yt_dlp_ejs missing (JS sites will fail)")


def _check_ffmpeg() -> ToolStatus:
    label = "ffmpeg"
    binary = shutil.which("ffmpeg")
    if not binary:
        return ToolStatus(label, False, "`ffmpeg` binary not found on PATH")
    try:
        completed = subprocess.run(
            [binary, "-version"],
            capture_output=True,
            text=True,
            check=False,
            timeout=5,
        )
    except Exception as exc:
        return ToolStatus(label, False, f"failed to exec: {exc}")
    if completed.returncode != 0:
        return ToolStatus(label, False, completed.stderr.strip() or "ffmpeg returned error")
    first_line = (completed.stdout or "").splitlines()[0] if completed.stdout else "ffmpeg present"
    return ToolStatus(label, True, first_line)


def _check_gemini_env(gemini_api_key: str | None = None) -> ToolStatus:
    label = "Gemini API key"
    # Prefer an explicit key passed from the UI; fall back to process env.
    key = gemini_api_key or os.environ.get(GEMINI_ENV_VAR)
    if key:
        return ToolStatus(label, True, f"{GEMINI_ENV_VAR} is set")
    return ToolStatus(label, False, f"{GEMINI_ENV_VAR} is not set")


def _check_mcp_health(gemini_api_key: str | None = None) -> ToolStatus:
    label = "MCP server"
    try:
        from fastmcp import Client  # type: ignore
        from fastmcp.client.transports import StdioTransport  # type: ignore
    except Exception as exc:  # pragma: no cover - defensive
        return ToolStatus(label, False, f"fastmcp missing: {exc}")

    # When running inside the Hugging Face Space, the repo root is the
    # working directory; keep this logic in sync with the Dockerfile so
    # that imports work both locally and in production.
    repo_root = Path(__file__).resolve().parents[1]
    mcp_src = repo_root / "mcp" / "src"
    existing_py_path = os.environ.get("PYTHONPATH", "")
    py_path = (
        f"{mcp_src}{os.pathsep}{existing_py_path}"
        if existing_py_path
        else str(mcp_src)
    )
    env = os.environ.copy()
    env["PYTHONPATH"] = py_path
    if gemini_api_key:
        env[GEMINI_ENV_VAR] = gemini_api_key

    server_entry = ["-m", "aileen3_mcp.server"]

    logging.warning(
        "MCP probe spawning server: cmd=%s args=%s PYTHONPATH=%s cwd=%s",
        sys.executable,
        server_entry,
        py_path,
        repo_root,
    )

    transport = StdioTransport(
        command=sys.executable,
        args=server_entry,
        env=env,
        cwd=str(repo_root),
    )

    async def probe() -> ToolStatus:
        try:
            async with Client(transport) as client:
                result = await client.call_tool("health", {})
        except Exception as exc:
            logging.warning("MCP health probe failed: %s", exc)
            return ToolStatus(label, False, f"Probe failed: {exc}")

        # FastMCP returns a CallToolResult; unwrap to the underlying payload if present.
        payload = getattr(result, "data", None) or getattr(result, "structured_content", None) or result

        if isinstance(payload, dict):
            ok = bool(payload.get("ok", False))
            detail = str(payload.get("detail", "no detail"))
        else:
            ok = False
            detail = str(payload)

        if not ok:
            logging.warning("MCP health probe reported not-ok: %s", detail)
        return ToolStatus(label, ok, detail)

    return asyncio.run(probe())


def run_health_report(gemini_api_key: str | None = None) -> HealthReport:
    tool_statuses = [
        _check_deno(),
        _check_yt_dlp_python(),
        _check_ffmpeg(),
        _check_gemini_env(gemini_api_key),
        _check_mcp_health(gemini_api_key),
    ]
    ok = all(status.ok for status in tool_statuses)
    if ok:
        summary = "All systems look good—ready for notebook-style experimentation."
    else:
        blocking = ", ".join(status.label for status in tool_statuses if not status.ok)
        summary = f"Needs attention: {blocking}."
    return HealthReport(ok=ok, summary=summary, tools=tool_statuses)


def _sanitize(text: str) -> str:
    return html.escape(text, quote=False)


def render_health_notice(gemini_api_key: str | None = None) -> str:
    report = run_health_report(gemini_api_key)
    state_class, icon = ("health-success", "✅") if report.ok else ("health-fail", "🧯")
    bullet_rows = "".join(
        f"<li>{'✅' if status.ok else '❌'} {_sanitize(status.label)}: "
        f"<strong>{'Ready' if status.ok else 'Needs attention'}</strong>"
        f"{'' if not status.detail else ' — ' + _sanitize(status.detail)}</li>"
        for status in report.tools
    )
    return (
        f"<div class='health-box {state_class}'>"
        f"<div class='health-head'>{icon} {_sanitize(report.summary)}</div>"
        f"<ul>{bullet_rows}</ul>"
        "</div>"
    )


def render_placeholder_notice() -> str:
    return (
        "<div class='health-box health-placeholder'>"
        "<div class='health-head'>🔍 Let's run a quick health check to verify everything is set up correctly.</div>"
        "</div>"
    )