#!/usr/bin/env python3

"""Download episodes from Kaizoku's StrawVerse-compatible provider bridge."""

import argparse
import json
import os
import re
import subprocess
import sys
import urllib.request
from pathlib import Path


PROJECT_ROOT = Path(__file__).resolve().parent
BRIDGE = PROJECT_ROOT / "providers" / "bridge.js"
PROVIDERS = ("anikoto", "anineko", "pahe")


def clean_component(value, default="Anime"):
    text = re.sub(r"[\\/:*?\"<>|]+", " ", str(value or "")).strip()
    text = re.sub(r"\s+", " ", text)
    return text.strip(". ") or default


def normalize_title(value):
    return re.sub(r"[^a-z0-9]+", " ", str(value or "").lower()).strip()


def parse_show_id(value, default_provider="anikoto"):
    text = str(value or "").strip()
    if ":" in text:
        provider, show_id = text.split(":", 1)
        provider = provider.strip().lower()
        if provider in PROVIDERS and show_id.strip():
            return provider, show_id.strip()
    return default_provider, text


def bridge(command, provider, *args):
    cmd = ["node", str(BRIDGE), command, provider, *[str(arg) for arg in args]]
    proc = subprocess.run(cmd, cwd=PROJECT_ROOT, text=True, capture_output=True, check=False)
    if proc.returncode != 0:
        raise RuntimeError((proc.stderr or proc.stdout or f"{command} failed").strip())
    try:
        return json.loads(proc.stdout or "{}")
    except json.JSONDecodeError as exc:
        raise RuntimeError(f"Provider bridge returned invalid JSON: {exc}") from exc


def provider_order(primary):
    ordered = []
    primary = str(primary or "").strip().lower()
    if primary in PROVIDERS:
        ordered.append(primary)
    for provider in PROVIDERS:
        if provider not in ordered:
            ordered.append(provider)
    return ordered


def find_provider_show(provider, title, original_provider, original_show_id):
    if provider == original_provider:
        return original_show_id
    query = str(title or "").strip()
    if not query:
        return ""
    payload = bridge("search", provider, query, 1)
    results = payload.get("results") or []
    if not results:
        return ""
    target = normalize_title(query)
    scored = []
    for item in results:
        candidate = normalize_title(item.get("title"))
        if not candidate:
            continue
        if candidate == target:
            score = 100
        elif target and (candidate in target or target in candidate):
            score = 75 - abs(len(candidate) - len(target))
        else:
            shared = set(target.split()) & set(candidate.split())
            score = len(shared) * 5
        scored.append((score, item))
    if not scored:
        return ""
    scored.sort(key=lambda row: row[0], reverse=True)
    if scored[0][0] <= 0:
        return ""
    provider_id = str(scored[0][1].get("provider_id") or scored[0][1].get("id") or "").strip()
    if ":" in provider_id:
        provider_id = provider_id.split(":", 1)[1].strip()
    return provider_id


def episode_values(spec, episodes):
    values = []
    by_number = {str(ep.get("number")).rstrip("0").rstrip("."): ep for ep in episodes}
    if not str(spec or "").strip():
        return episodes
    for part in re.split(r"[\s,]+", str(spec).strip()):
        if not part:
            continue
        if "-" in part:
            start, end = part.split("-", 1)
            try:
                left = int(float(start))
                right = int(float(end))
            except ValueError:
                continue
            step = 1 if right >= left else -1
            for number in range(left, right + step, step):
                item = by_number.get(str(number))
                if item and item not in values:
                    values.append(item)
            continue
        item = by_number.get(str(float(part)).rstrip("0").rstrip(".")) if re.match(r"^\d+(?:\.\d+)?$", part) else None
        if item and item not in values:
            values.append(item)
    return values


def requested_episode_numbers(spec, episodes):
    text = str(spec or "").strip()
    if not text:
        return [episode.get("number") for episode in episodes or [] if episode.get("number") not in (None, "")]
    numbers = []
    for part in re.split(r"[\s,]+", text):
        if not part:
            continue
        if "-" in part:
            start, end = part.split("-", 1)
            try:
                left = int(float(start))
                right = int(float(end))
            except ValueError:
                continue
            step = 1 if right >= left else -1
            numbers.extend(range(left, right + step, step))
            continue
        if re.match(r"^\d+(?:\.\d+)?$", part):
            numbers.append(float(part) if "." in part else int(part))
    return numbers


def wanted_episodes(spec, episodes):
    by_number = {str(ep.get("number")).rstrip("0").rstrip("."): ep for ep in episodes or []}
    wanted = []
    for number in requested_episode_numbers(spec, episodes):
        key = str(number).rstrip("0").rstrip(".")
        wanted.append(by_number.get(key) or {"number": number, "id": ""})
    return wanted


def episode_by_number(number, episodes):
    wanted = str(number).rstrip("0").rstrip(".")
    for episode in episodes or []:
        current = str(episode.get("number")).rstrip("0").rstrip(".")
        if current == wanted:
            return episode
    return None


def ffmpeg_headers(headers):
    pairs = []
    for key, value in (headers or {}).items():
        if value:
            pairs.append(f"{key}: {value}")
    return "\r\n".join(pairs) + ("\r\n" if pairs else "")


def download_subtitles(subtitles, output_base):
    saved = []
    english = [
        sub for sub in subtitles or []
        if sub.get("url") and re.search(r"eng|english", str(sub.get("lang") or ""), re.I)
    ] or [sub for sub in subtitles or [] if sub.get("url")]
    for index, sub in enumerate(english[:1], start=1):
        url = sub["url"]
        suffix = ".srt" if ".srt" in url.lower() else ".vtt"
        target = output_base.with_suffix(f".eng{suffix}" if index == 1 else f".eng-{index}{suffix}")
        request = urllib.request.Request(url, headers={"User-Agent": "Mozilla/5.0", "Referer": sub.get("referer") or ""})
        with urllib.request.urlopen(request, timeout=30) as response:
            target.write_bytes(response.read())
        saved.append(target)
    return saved


def download_episode(stream, target):
    cmd = ["ffmpeg", "-hide_banner", "-loglevel", "info", "-y"]
    headers = ffmpeg_headers(stream.get("headers") or {})
    if headers:
        cmd.extend(["-headers", headers])
    referer = (stream.get("headers") or {}).get("Referer")
    if referer:
        cmd.extend(["-referer", referer])
    cmd.extend(["-i", stream["url"], "-c", "copy", "-bsf:a", "aac_adtstoasc", str(target)])
    return subprocess.call(cmd)


def provider_episode_candidates(primary_provider, primary_show_id, title, wanted_episode):
    number = wanted_episode.get("number")
    for provider in provider_order(primary_provider):
        try:
            provider_show_id = find_provider_show(provider, title, primary_provider, primary_show_id)
            if not provider_show_id:
                print(f"Fallback skipped {provider}: no matching title.")
                continue
            episodes = bridge("episodes", provider, provider_show_id).get("episodes") or []
            episode = episode_by_number(number, episodes)
            if not episode:
                print(f"Fallback skipped {provider}: episode {number} is not listed.")
                continue
            yield provider, provider_show_id, episode
        except Exception as exc:
            print(f"Fallback skipped {provider}: {exc}")


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--provider", default="anikoto")
    parser.add_argument("--show-id", required=True)
    parser.add_argument("--title", required=True)
    parser.add_argument("--episodes", required=True)
    parser.add_argument("--mode", choices=("sub", "dub"), default="sub")
    parser.add_argument("--quality", default="best")
    parser.add_argument("--output-dir", required=True)
    args = parser.parse_args()

    provider, provider_show_id = parse_show_id(args.show_id, args.provider)
    info = bridge("info", provider, provider_show_id)
    episodes = bridge("episodes", provider, provider_show_id).get("episodes") or []
    wanted = wanted_episodes(args.episodes, episodes)
    if not wanted:
        raise SystemExit(f"No matching episodes for spec {args.episodes!r}.")

    series_title = clean_component(args.title or info.get("title"))
    output_dir = Path(args.output_dir).expanduser()
    output_dir.mkdir(parents=True, exist_ok=True)

    print(f"Provider: {provider}")
    print(f"Title: {series_title}")
    print(f"Episodes: {', '.join(str(ep.get('number')) for ep in wanted)}")
    exit_code = 0
    for ep in wanted:
        number = ep.get("number")
        ep_id = ep.get("id")
        padded = f"{int(float(number)):02d}" if str(number).replace(".", "", 1).isdigit() else str(number)
        basename = f"{series_title} - S01E{padded}"
        target = output_dir / f"{basename}.mp4"
        last_error = None
        downloaded = False
        for active_provider, _active_show_id, active_ep in provider_episode_candidates(provider, provider_show_id, args.title or info.get("title"), ep):
            try:
                active_ep_id = active_ep.get("id")
                print(f"Resolving episode {number} on {active_provider} ({args.mode}, {args.quality})...")
                stream = bridge("resolve", active_provider, active_ep_id, args.mode, args.quality)
                print(f"Downloading episode {number} from {active_provider} {stream.get('quality') or 'auto'}...")
                code = download_episode(stream, target)
                if code != 0:
                    last_error = RuntimeError(f"ffmpeg failed on {active_provider} with exit code {code}")
                    print(str(last_error), file=sys.stderr)
                    continue
                try:
                    for subtitle_path in download_subtitles(stream.get("subtitles") or [], target):
                        print(f"Saved subtitle: {subtitle_path.name}")
                except Exception as exc:
                    print(f"Subtitle download skipped: {exc}")
                print(f"Saved: {target.name}")
                downloaded = True
                break
            except Exception as exc:
                last_error = exc
                print(f"Provider {active_provider} failed for episode {number}: {exc}", file=sys.stderr)
        if not downloaded:
            print(f"Episode {number} failed on all providers: {last_error}", file=sys.stderr)
            exit_code = 1
            break
    raise SystemExit(exit_code)


if __name__ == "__main__":
    main()