"""SRT 字幕文件写入与双语合并。"""

from __future__ import annotations

from pathlib import Path

from .types import Subtitle


def _format_ts(seconds: float) -> str:
    """秒 → SRT 时间戳 HH:MM:SS,mmm。"""
    if seconds < 0:
        seconds = 0.0
    ms = int(round((seconds - int(seconds)) * 1000))
    s = int(seconds) % 60
    m = (int(seconds) // 60) % 60
    h = int(seconds) // 3600
    if ms == 1000:  # 四舍五入进位
        ms = 0
        s += 1
        if s == 60:
            s = 0
            m += 1
            if m == 60:
                m = 0
                h += 1
    return f"{h:02d}:{m:02d}:{s:02d},{ms:03d}"


def write_srt(subtitles: list[Subtitle], path: Path) -> Path:
    """写单语 SRT。"""
    path.parent.mkdir(parents=True, exist_ok=True)
    lines: list[str] = []
    for i, sub in enumerate(subtitles, 1):
        lines.append(str(i))
        lines.append(f"{_format_ts(sub.start)} --> {_format_ts(sub.end)}")
        lines.append(sub.text)
        lines.append("")
    path.write_text("\n".join(lines), encoding="utf-8")
    return path


def write_bilingual_srt(
    en_subs: list[Subtitle],
    zh_texts: list[str],
    path: Path,
) -> Path:
    """写双语合并 SRT：英文在上、中文在下，同一时间戳。

    Args:
        en_subs: 英文字幕条目
        zh_texts: 与 en_subs 等长、顺序对应的中文译文
        path: 输出路径
    """
    if len(en_subs) != len(zh_texts):
        raise ValueError(
            f"英文字幕数({len(en_subs)}) 与中文译文数({len(zh_texts)}) 不一致"
        )
    path.parent.mkdir(parents=True, exist_ok=True)
    lines: list[str] = []
    for i, (sub, zh) in enumerate(zip(en_subs, zh_texts), 1):
        lines.append(str(i))
        lines.append(f"{_format_ts(sub.start)} --> {_format_ts(sub.end)}")
        lines.append(sub.text)
        lines.append(zh)
        lines.append("")
    path.write_text("\n".join(lines), encoding="utf-8")
    return path