from __future__ import annotations

import os

from dataclasses import dataclass
from pathlib import Path
from typing import Any, Dict, List, Optional, Sequence

from SYS.logger import debug
from SYS.utils import ensure_directory
from models import DownloadOptions


def _get_nested(config: Dict[str, Any], *path: str) -> Any:
    cur: Any = config
    for key in path:
        if not isinstance(cur, dict):
            return None
        cur = cur.get(key)
    return cur


def _parse_csv_list(value: Any) -> Optional[List[str]]:
    if value is None:
        return None
    if isinstance(value, list):
        out: List[str] = []
        for item in value:
            s = str(item).strip()
            if s:
                out.append(s)
        return out or None
    s = str(value).strip()
    if not s:
        return None
    # allow either JSON-ish list strings or simple comma-separated values
    if s.startswith("[") and s.endswith("]"):
        s = s[1:-1]
    parts = [p.strip() for p in s.split(",")]
    parts = [p for p in parts if p]
    return parts or None


@dataclass(slots=True)
class YtDlpDefaults:
    """User-tunable defaults for yt-dlp behavior.

    Recommended config.conf keys (top-level dotted keys):
      - ytdlp.video_format="bestvideo+bestaudio/best"
      - ytdlp.audio_format="251/140/bestaudio"
      - ytdlp.format_sort="res:2160,res:1440,res:1080,res:720,res"

    Cookies:
      - cookies="C:\\path\\cookies.txt" (already supported by config.resolve_cookies_path)
    """

    video_format: str = "bestvideo+bestaudio/best"
    audio_format: str = "251/140/bestaudio"
    format_sort: Optional[List[str]] = None


class YtDlpTool:
    """Centralizes yt-dlp defaults and translation helpers.

    This is intentionally small and dependency-light so cmdlets can use it without
    forcing a full refactor.
    """

    def __init__(
        self, config: Optional[Dict[str, Any]] = None, *, script_dir: Optional[Path] = None
    ) -> None:
        self._config: Dict[str, Any] = dict(config or {})
        # `resolve_cookies_path` expects the app root so it can fall back to ./cookies.txt.
        # This file lives under ./tool/, so default to the parent directory.
        self._script_dir = script_dir or Path(__file__).resolve().parent.parent
        self.defaults = self._load_defaults()
        self._cookiefile: Optional[Path] = self._init_cookiefile()

    def _init_cookiefile(self) -> Optional[Path]:
        """Resolve cookies once at tool init (yt-dlp is the primary consumer)."""
        try:
            from config import resolve_cookies_path

            resolved = resolve_cookies_path(self._config, script_dir=self._script_dir)
            if resolved is not None and resolved.is_file():
                return resolved
        except Exception:
            pass
        return None

    def _load_defaults(self) -> YtDlpDefaults:
        cfg = self._config

        # NOTE: `YtDlpDefaults` is a slots dataclass. Referencing defaults via
        # `YtDlpDefaults.video_format` yields a `member_descriptor`, not the
        # default string value. Use an instance for fallback defaults.
        _fallback_defaults = YtDlpDefaults()

        tool_block = _get_nested(cfg, "tool", "ytdlp")
        if not isinstance(tool_block, dict):
            tool_block = {}

        ytdlp_block = cfg.get("ytdlp") if isinstance(cfg.get("ytdlp"), dict) else {}
        if not isinstance(ytdlp_block, dict):
            ytdlp_block = {}

        # Accept both nested and flat styles.
        video_format = (
            tool_block.get("video_format")
            or tool_block.get("format")
            or ytdlp_block.get("video_format")
            or ytdlp_block.get("video")
            or ytdlp_block.get("format_video")
            or cfg.get("ytdlp_video_format")
        )
        audio_format = (
            tool_block.get("audio_format")
            or ytdlp_block.get("audio_format")
            or ytdlp_block.get("audio")
            or ytdlp_block.get("format_audio")
            or cfg.get("ytdlp_audio_format")
        )

        # Also accept dotted keys written as nested dicts: ytdlp.format.video, ytdlp.format.audio
        nested_video = _get_nested(cfg, "ytdlp", "format", "video")
        nested_audio = _get_nested(cfg, "ytdlp", "format", "audio")

        fmt_sort_val = (
            tool_block.get("format_sort")
            or ytdlp_block.get("format_sort")
            or ytdlp_block.get("formatSort")
            or cfg.get("ytdlp_format_sort")
            or _get_nested(cfg, "ytdlp", "format", "sort")
        )
        fmt_sort = _parse_csv_list(fmt_sort_val)

        defaults = YtDlpDefaults(
            video_format=str(nested_video or video_format or _fallback_defaults.video_format),
            audio_format=str(nested_audio or audio_format or _fallback_defaults.audio_format),
            format_sort=fmt_sort,
        )

        return defaults

    def resolve_cookiefile(self) -> Optional[Path]:
        return self._cookiefile

    def default_format(self, mode: str) -> str:
        m = str(mode or "").lower().strip()
        if m == "audio":
            return self.defaults.audio_format
        return self.defaults.video_format

    def build_ytdlp_options(self, opts: DownloadOptions) -> Dict[str, Any]:
        """Translate DownloadOptions into yt-dlp API options."""
        ensure_directory(opts.output_dir)
        outtmpl = str((opts.output_dir / "%(title)s.%(ext)s").resolve())
        base_options: Dict[str, Any] = {
            "outtmpl": outtmpl,
            "quiet": True,
            "no_warnings": True,
            "noprogress": True,
            "socket_timeout": 30,
            "retries": 10,
            "fragment_retries": 10,
            "http_chunk_size": 10_485_760,
            "restrictfilenames": True,
        }

        try:
            repo_root = Path(__file__).resolve().parents[1]
            bundled_ffmpeg_dir = repo_root / "MPV" / "ffmpeg" / "bin"
            if bundled_ffmpeg_dir.exists():
                base_options.setdefault("ffmpeg_location", str(bundled_ffmpeg_dir))
        except Exception:
            pass

        try:
            if os.name == "nt":
                base_options.setdefault("file_access_retries", 40)
        except Exception:
            pass

        if opts.cookies_path and opts.cookies_path.is_file():
            base_options["cookiefile"] = str(opts.cookies_path)
        else:
            cookiefile = self.resolve_cookiefile()
            if cookiefile is not None and cookiefile.is_file():
                base_options["cookiefile"] = str(cookiefile)

        if opts.no_playlist:
            base_options["noplaylist"] = True

        fmt = opts.ytdl_format or self.default_format(opts.mode)
        base_options["format"] = fmt

        if opts.mode == "audio":
            base_options["postprocessors"] = [{"key": "FFmpegExtractAudio"}]
        else:
            format_sort = self.defaults.format_sort or [
                "res:4320",
                "res:2880",
                "res:2160",
                "res:1440",
                "res:1080",
                "res:720",
                "res",
            ]
            base_options["format_sort"] = format_sort

        if getattr(opts, "embed_chapters", False):
            pps = base_options.get("postprocessors")
            if not isinstance(pps, list):
                pps = []
            already_has_metadata = any(
                isinstance(pp, dict) and str(pp.get("key") or "") == "FFmpegMetadata" for pp in pps
            )
            if not already_has_metadata:
                pps.append(
                    {
                        "key": "FFmpegMetadata",
                        "add_metadata": True,
                        "add_chapters": True,
                        "add_infojson": "if_exists",
                    }
                )
            base_options["postprocessors"] = pps

            if opts.mode != "audio":
                base_options.setdefault("merge_output_format", "mkv")

        if getattr(opts, "write_sub", False):
            base_options["writesubtitles"] = True
            base_options["writeautomaticsub"] = True
            base_options["subtitlesformat"] = "vtt"

        if opts.clip_sections:
            sections: List[str] = []

            def _secs_to_hms(seconds: float) -> str:
                total = max(0, int(seconds))
                minutes, secs = divmod(total, 60)
                hours, minutes = divmod(minutes, 60)
                return f"{hours:02d}:{minutes:02d}:{secs:02d}"

            for section_range in str(opts.clip_sections).split(","):
                section_range = section_range.strip()
                if not section_range:
                    continue
                try:
                    start_s_raw, end_s_raw = section_range.split("-", 1)
                    start_s = float(start_s_raw.strip())
                    end_s = float(end_s_raw.strip())
                    if start_s >= end_s:
                        continue
                    sections.append(f"*{_secs_to_hms(start_s)}-{_secs_to_hms(end_s)}")
                except (ValueError, AttributeError):
                    continue

            if sections:
                base_options["download_sections"] = sections
                # Clipped outputs should begin with a keyframe; otherwise players (notably mpv)
                # can show audio before video or a black screen until the next keyframe.
                # yt-dlp implements this by forcing keyframes at cut points.
                base_options["force_keyframes_at_cuts"] = True
                debug(f"Download sections configured: {', '.join(sections)}")

        if opts.playlist_items:
            base_options["playlist_items"] = opts.playlist_items

        if not opts.quiet:
            debug(f"yt-dlp: mode={opts.mode}, format={base_options.get('format')}")

        return base_options

    def build_yt_dlp_cli_args(
        self,
        *,
        url: str,
        output_dir: Optional[Path] = None,
        ytdl_format: Optional[str] = None,
        playlist_items: Optional[str] = None,
        no_playlist: bool = False,
        quiet: bool = True,
        extra_args: Optional[Sequence[str]] = None,
    ) -> List[str]:
        """Build a yt-dlp command line (argv list).

        This is primarily for debug output or subprocess execution.
        """
        argv: List[str] = ["yt-dlp"]
        if quiet:
            argv.extend(["--quiet", "--no-warnings"])
        argv.append("--no-progress")

        cookiefile = self.resolve_cookiefile()
        if cookiefile is not None:
            argv.extend(["--cookies", str(cookiefile)])

        if no_playlist:
            argv.append("--no-playlist")
        if playlist_items:
            argv.extend(["--playlist-items", str(playlist_items)])

        fmt = (ytdl_format or "").strip()
        if fmt:
            # Use long form to avoid confusion with app-level flags.
            argv.extend(["--format", fmt])

        if self.defaults.format_sort:
            for sort_key in self.defaults.format_sort:
                argv.extend(["-S", sort_key])

        if output_dir is not None:
            outtmpl = str((output_dir / "%(title)s.%(ext)s").resolve())
            argv.extend(["-o", outtmpl])

        if extra_args:
            argv.extend([str(a) for a in extra_args if str(a).strip()])

        argv.append(str(url))
        return argv

    def debug_print_cli(self, argv: Sequence[str]) -> None:
        try:
            debug("yt-dlp argv: " + " ".join(str(a) for a in argv))
        except Exception:
            pass