"""Read finalized demonstration tracks without touching active recorders."""

import json
from pathlib import Path
import tempfile

from artemis.utils.video import VideoRecordingResult, render_timeline_clip


class SavedVideoSource:
    def __init__(self, root: Path, track: dict):
        self.root = root.resolve()
        self.track = track
        self.segments = []
        for segment in track["segments"]:
            path = (self.root / segment["file"]).resolve()
            if not path.is_relative_to(self.root) or not path.is_file():
                raise ValueError("示范录像文件不存在或不属于当前任务")
            start = float(segment["offset_ms"]) / 1000
            end = start + float(segment["duration_ms"]) / 1000
            if end > start:
                self.segments.append({"path": path, "start": start, "end": end})
        if not self.segments:
            raise ValueError("示范录像没有可分析的片段")
        self.start = min(s["start"] for s in self.segments)
        self.end = max(s["end"] for s in self.segments)

    async def extract_segment_metadata(
        self, start: float, end: float | None = None
    ) -> VideoRecordingResult:
        start, end = max(start, self.start), min(end if end is not None else self.end, self.end)
        if end <= start:
            return VideoRecordingResult(success=False, message="所选区间没有示范录像")
        # Analyzer owns only these disposable copies, never the source evidence.
        folder = Path(tempfile.mkdtemp(prefix="artemis-demo-analysis-"))
        path = folder / "clip.mp4"
        landscape = self.track["kind"] == "computer"
        ok = False
        try:
            ok = await render_timeline_clip(
                self.segments,
                start,
                end,
                path,
                canvas_width=1280 if landscape else 720,
                canvas_height=720 if landscape else 1280,
            )
        finally:
            if not ok:
                path.unlink(missing_ok=True)
                folder.rmdir()
        if not ok:
            return VideoRecordingResult(success=False, message="示范录像片段读取失败")
        return VideoRecordingResult(
            success=True,
            message="已读取保存的示范录像",
            video_path=path,
            duration_seconds=end - start,
            actual_start_relative_time=start,
            source_revision=self.track["id"],
            file_size_mb=path.stat().st_size / 1024 / 1024,
        )


def android_track(root: Path, folder: Path, demo_id: str) -> dict:
    manifest = json.loads((folder / "recording.json").read_text(encoding="utf-8"))
    return {
        "id": f"{demo_id}-android",
        "kind": "android",
        "label": "安卓人工示范",
        "segments": [
            {**item, "file": (folder / item["file"]).relative_to(root).as_posix()}
            for item in manifest["segments"]
        ],
    }