from __future__ import annotations

import csv
import json
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any

from .fixtures import ensure_synthetic_fixture


DATASET_NAMES = [
    "youcook2",
    "ave",
    "ava_active_speaker",
    "tvqa",
    "activitynet_captions",
]


@dataclass(frozen=True)
class Clip:
    dataset: str
    video_id: str
    media_path: Path | None
    duration: float
    windows: list[dict[str, Any]] = field(default_factory=list)
    metadata: dict[str, Any] = field(default_factory=dict)


def _load_json(path: Path) -> Any:
    with path.open("r", encoding="utf-8") as handle:
        return json.load(handle)


def _read_csv_rows(path: Path) -> list[dict[str, str]]:
    with path.open("r", encoding="utf-8", newline="") as handle:
        return list(csv.DictReader(handle))


def _duration_from_manifest(meta: dict[str, Any], default: float = 10.0) -> float:
    for key in ("duration", "duration_seconds", "end_time"):
        if key in meta:
            try:
                return float(meta[key])
            except (TypeError, ValueError):
                pass
    return default


def discover_dataset(dataset: str, root: Path, limit: int | None = None) -> list[Clip]:
    dataset_root = root / dataset
    videos = sorted((dataset_root / "videos").glob("*.mp4"))
    clips: list[Clip] = []
    if not videos:
        return clips

    annotation_json: dict[str, Any] = {}
    for candidate in [
        dataset_root / "annotations.json",
        dataset_root / "captions.json",
        dataset_root / "labels.json",
    ]:
        if candidate.exists():
            loaded = _load_json(candidate)
            if isinstance(loaded, dict):
                annotation_json = loaded
            break

    annotation_csv: list[dict[str, str]] = []
    for candidate in [
        dataset_root / "annotations.csv",
        dataset_root / "labels.csv",
    ]:
        if candidate.exists():
            annotation_csv = _read_csv_rows(candidate)
            break

    csv_by_video: dict[str, list[dict[str, str]]] = {}
    for row in annotation_csv:
        vid = row.get("video_id") or row.get("id") or row.get("video") or ""
        if vid:
            csv_by_video.setdefault(vid, []).append(row)

    for video in videos[:limit]:
        video_id = video.stem
        meta = annotation_json.get(video_id, {}) if isinstance(annotation_json, dict) else {}
        if not isinstance(meta, dict):
            meta = {"annotation": meta}
        rows = csv_by_video.get(video_id, [])
        windows = _windows_from_annotations(dataset, video_id, meta, rows)
        clips.append(
            Clip(
                dataset=dataset,
                video_id=video_id,
                media_path=video,
                duration=_duration_from_manifest(meta, default=max(10.0, len(windows) * 2.0)),
                windows=windows,
                metadata={"source": "real_adapter", "annotation_rows": len(rows), **meta},
            )
        )
    return clips


def _windows_from_annotations(
    dataset: str,
    video_id: str,
    meta: dict[str, Any],
    rows: list[dict[str, str]],
) -> list[dict[str, Any]]:
    windows: list[dict[str, Any]] = []
    segments = meta.get("segments") or meta.get("annotations") or meta.get("timestamps") or []
    if isinstance(segments, list):
        for idx, segment in enumerate(segments):
            if not isinstance(segment, dict):
                continue
            start = float(segment.get("start", segment.get("start_time", idx * 2.0)))
            end = float(segment.get("end", segment.get("end_time", start + 2.0)))
            label = " ".join(
                str(segment.get(key, ""))
                for key in ["label", "caption", "sentence", "activity", "action"]
            ).lower()
            windows.append(_annotation_window(dataset, video_id, idx, start, end, label))
    for row in rows:
        idx = len(windows)
        start = float(row.get("start", row.get("start_time", idx * 2.0)) or idx * 2.0)
        end = float(row.get("end", row.get("end_time", start + 2.0)) or start + 2.0)
        label = " ".join(str(v) for v in row.values()).lower()
        windows.append(_annotation_window(dataset, video_id, idx, start, end, label))
    return windows


def _annotation_window(
    dataset: str,
    video_id: str,
    index: int,
    start: float,
    end: float,
    label: str,
) -> dict[str, Any]:
    visual = {"motion_continuous"}
    audio = set()
    subtitle = set()
    if any(word in label for word in ["speak", "speaker", "dialog", "talk", "voice"]):
        visual.update({"person_visible", "speaker_visible", "mouth_open"})
        audio.add("speech")
        subtitle.add("subtitle_speech")
    if any(word in label for word in ["cook", "chop", "cut", "food", "recipe"]):
        visual.update({"scene_kitchen", "cooking_action", "object_food"})
        subtitle.add("recipe_step")
    if any(word in label for word in ["chop", "cut"]):
        visual.add("chopping")
        audio.add("chop_sound")
    if any(word in label for word in ["music", "sound", "audio", "event"]):
        audio.add("event_sound")
        visual.add("event_visible")
    if dataset == "ava_active_speaker":
        visual.update({"person_visible", "speaker_visible", "mouth_open"})
        audio.add("speech")
        subtitle.add("subtitle_speech")
    if dataset == "tvqa":
        subtitle.add("subtitle_speech")
    return {
        "video_id": video_id,
        "index": index,
        "start": start,
        "end": end,
        "visual_atoms": sorted(visual),
        "audio_atoms": sorted(audio),
        "subtitle_ocr_atoms": sorted(subtitle),
    }


def load_clips(
    root: Path,
    datasets: list[str] | None = None,
    limit: int | None = None,
    synthetic_if_empty: bool = True,
    fixture_root: Path = Path("data/fixtures"),
) -> list[Clip]:
    wanted = datasets or DATASET_NAMES
    clips: list[Clip] = []
    per_dataset_limit = None if limit is None else max(1, limit)
    for dataset in wanted:
        clips.extend(discover_dataset(dataset, root, per_dataset_limit))
        if limit is not None and len(clips) >= limit:
            return clips[:limit]
    if clips or not synthetic_if_empty:
        return clips[:limit]
    return ensure_synthetic_fixture(fixture_root, limit=limit or 10)


def adapter_status(root: Path) -> list[dict[str, Any]]:
    status: list[dict[str, Any]] = []
    for dataset in DATASET_NAMES:
        dataset_root = root / dataset
        videos = sorted((dataset_root / "videos").glob("*.mp4"))
        missing = None
        if not dataset_root.exists():
            missing = str(dataset_root)
        elif not videos:
            missing = str(dataset_root / "videos/*.mp4")
        status.append(
            {
                "dataset": dataset,
                "root": str(dataset_root),
                "clips_found": len(videos),
                "ready": bool(videos),
                "smallest_missing_path": missing,
            }
        )
    return status