# app/srt_parser.py
import re
from typing import List, Dict


SRT_BLOCK_RE = re.compile(
    r"(\d+)\s*\n"
    r"(\d{2}:\d{2}:\d{2},\d{3})\s-->\s(\d{2}:\d{2}:\d{2},\d{3})\s*\n"
    r"(.*?)(?=\n{2,}|\Z)",
    re.DOTALL,
)


def parse_srt(content: str) -> List[Dict[str, str]]:
    normalized = content.replace("\r\n", "\n").replace("\r", "\n").strip()

    blocks = []
    for match in SRT_BLOCK_RE.finditer(normalized):
        index, start, end, text = match.groups()
        blocks.append(
            {
                "index": int(index),
                "start": start,
                "end": end,
                "text": text.strip(),
            }
        )

    return blocks


def build_srt(blocks: List[Dict[str, str]]) -> str:
    output = []

    for i, block in enumerate(blocks, start=1):
        output.append(str(i))
        output.append(f"{block['start']} --> {block['end']}")
        output.append(block["text"])
        output.append("")

    return "\n".join(output).strip() + "\n"