"""撕段时间线合并（与离线 demo 一致）。"""

from __future__ import annotations

from collections import Counter


def merge_tear_segments(
    rows: list[tuple[int, float, bool, str]],
    min_tear_sec: float = 3.0,
    min_gap_sec: float = 1.5,
) -> list[dict]:
    """
    rows: (frame_idx_in_clip, abs_time_sec, is_tear, consumable_label_or_empty)
    """
    raw_segs: list[dict] = []
    cur: dict | None = None

    for frame_idx, t, is_tear, label in rows:
        if is_tear:
            if cur is None:
                cur = {
                    "t0": t,
                    "t1": t,
                    "f0": frame_idx,
                    "f1": frame_idx,
                    "labels": [],
                }
            else:
                gap = t - cur["t1"]
                if gap > min_gap_sec:
                    raw_segs.append(cur)
                    cur = {
                        "t0": t,
                        "t1": t,
                        "f0": frame_idx,
                        "f1": frame_idx,
                        "labels": [],
                    }
            cur["t1"] = t
            cur["f1"] = frame_idx
            if label:
                cur["labels"].append(label)
        else:
            if cur is not None:
                gap = t - cur["t1"]
                if gap > min_gap_sec:
                    raw_segs.append(cur)
                    cur = None

    if cur is not None:
        raw_segs.append(cur)

    valid: list[dict] = []
    for s in raw_segs:
        dur = s["t1"] - s["t0"]
        if dur >= min_tear_sec - 1e-9:
            valid.append(s)

    out: list[dict] = []
    for i, s in enumerate(valid, 1):
        top_label = (
            Counter(s["labels"]).most_common(1)[0][0]
            if s["labels"]
            else "（未识别耗材）"
        )
        out.append(
            {
                "index": i,
                "start_sec": s["t0"],
                "end_sec": s["t1"],
                "duration_sec": s["t1"] - s["t0"],
                "consumable": top_label,
                "start_frame": s["f0"],
                "end_frame": s["f1"],
            }
        )
    return out