subfox/app/services/subtitle_service.py

import re
from app.translators.factory import get_translator


def parse_srt(content: str):
    content = content.replace("\r\n", "\n").replace("\r", "\n").strip()
    raw_blocks = re.split(r"\n\s*\n", content)
    blocks = []

    for raw in raw_blocks:
        lines = raw.strip().split("\n")
        if len(lines) < 3:
            continue

        try:
            index = int(lines[0].strip())
        except ValueError:
            continue

        if "-->" not in lines[1]:
            continue

        start, end = [x.strip() for x in lines[1].split("-->", 1)]
        text = "\n".join(lines[2:]).strip()

        blocks.append(
            {
                "index": index,
                "start": start,
                "end": end,
                "text": text,
            }
        )

    return blocks


def build_srt(blocks):
    output = []
    for b in blocks:
        output.append(
            f"{b['index']}\n{b['start']} --> {b['end']}\n{b['text']}\n"
        )
    return "\n".join(output)


def _make_translator(mode=None, source_lang="auto", target_lang="da"):
    attempts = [
        lambda: get_translator(mode=mode, source_lang=source_lang, target_lang=target_lang),
        lambda: get_translator(mode, source_lang, target_lang),
        lambda: get_translator(mode=mode),
        lambda: get_translator(mode),
        lambda: get_translator(),
    ]

    last_error = None
    for attempt in attempts:
        try:
            translator = attempt()
            if translator is not None:
                return translator
        except Exception as e:
            last_error = e

    raise RuntimeError(f"Could not create translator via get_translator(): {last_error}")


def _translate_blocks(
    translator,
    blocks,
    source_lang="auto",
    target_lang="da",
    progress_callback=None,
):
    if hasattr(translator, "translate_blocks"):
        return translator.translate_blocks(
            blocks,
            source_lang,
            target_lang,
            progress_callback=progress_callback,
        )

    if hasattr(translator, "translate_batch"):
        translated_texts = translator.translate_batch(blocks, source_lang, target_lang)

        output = []
        total = len(blocks)

        for i, (block, translated_text) in enumerate(zip(blocks, translated_texts), start=1):
            new_block = dict(block)

            if isinstance(translated_text, dict):
                translated_text = (
                    translated_text.get("text")
                    or translated_text.get("translated_text")
                    or translated_text.get("translation")
                    or block["text"]
                )

            new_block["text"] = str(translated_text).strip()
            output.append(new_block)

            if progress_callback:
                progress_callback(i, total)

        return output

    if hasattr(translator, "translate"):
        output = []
        total = len(blocks)

        for i, block in enumerate(blocks, start=1):
            new_block = dict(block)
            try:
                translated = translator.translate(block["text"], source_lang, target_lang)
            except TypeError:
                translated = translator.translate(block["text"])

            new_block["text"] = str(translated).strip()
            output.append(new_block)

            if progress_callback:
                progress_callback(i, total)

        return output

    if callable(translator):
        output = []
        total = len(blocks)

        for i, block in enumerate(blocks, start=1):
            new_block = dict(block)
            try:
                translated = translator(block["text"], source_lang, target_lang)
            except TypeError:
                translated = translator(block["text"])

            new_block["text"] = str(translated).strip()
            output.append(new_block)

            if progress_callback:
                progress_callback(i, total)

        return output

    raise TypeError(f"Unsupported translator interface: {type(translator)}")


def translate_srt_content(
    content,
    translator=None,
    mode=None,
    source_lang="auto",
    target_lang="da",
    job_id=None,
    progress_callback=None,
    **kwargs,
):
    print("DEBUG: ===== START translate_srt_content =====")
    print("DEBUG: mode:", mode)
    print("DEBUG: source_lang:", source_lang)
    print("DEBUG: target_lang:", target_lang)
    print("DEBUG: job_id:", job_id)
    print("DEBUG: extra kwargs:", kwargs)

    blocks = parse_srt(content)

    print("DEBUG: blocks count:", len(blocks))
    print("DEBUG: first block:", blocks[0] if blocks else "NONE")

    if not blocks:
        raise ValueError("No SRT blocks could be parsed from content")

    if translator is None:
        translator = _make_translator(
            mode=mode,
            source_lang=source_lang,
            target_lang=target_lang,
        )
        print("DEBUG: translator created:", type(translator))

    translated_blocks = _translate_blocks(
        translator,
        blocks,
        source_lang=source_lang,
        target_lang=target_lang,
        progress_callback=progress_callback,
    )

    print("DEBUG: translated blocks count:", len(translated_blocks))
    print("DEBUG: ===== END translate_srt_content =====")

    return build_srt(translated_blocks)