import os
import re
import unicodedata
from datetime import datetime


def slugify(text: str) -> str:
    for src, dst in [("ä","a"),("ö","o"),("ü","u"),("Ä","a"),("Ö","o"),("Ü","u"),("ß","ss")]:
        text = text.replace(src, dst)
    text = unicodedata.normalize("NFKD", text)
    text = "".join(c for c in text if unicodedata.category(c) != "Mn")
    text = text.lower()
    text = re.sub(r"[^a-z0-9]+", "-", text)
    return text.strip("-")


def save_transcript(
    title: str,
    content: str,
    output_dir: str,
    dt: datetime | None = None,
) -> str:
    if dt is None:
        dt = datetime.now()
    slug = slugify(title)[:60]
    filename = f"{dt.strftime('%Y-%m-%d-%H%M')}-{slug}.md"
    os.makedirs(output_dir, exist_ok=True)
    path = os.path.join(output_dir, filename)
    with open(path, "w", encoding="utf-8") as f:
        f.write(f"---\ndate: {dt.isoformat(timespec='seconds')}\ntags: [transkript]\n---\n\n")
        f.write(f"# {title}\n\n")
        f.write(content)
        if not content.endswith("\n"):
            f.write("\n")
    return path


def read_transcript(output_dir: str, filename: str) -> str | None:
    """Return file content if filename is a plain .md file inside output_dir."""
    if os.path.basename(filename) != filename or not filename.endswith(".md"):
        return None
    path = os.path.join(output_dir, filename)
    if not os.path.exists(path):
        return None
    with open(path, encoding="utf-8") as f:
        return f.read()


def list_transcripts(output_dir: str, limit: int = 20) -> list[dict]:
    if not os.path.exists(output_dir):
        return []
    files = sorted(
        [f for f in os.listdir(output_dir) if f.endswith(".md")],
        reverse=True,
    )[:limit]
    result = []
    for f in files:
        full = os.path.join(output_dir, f)
        stat = os.stat(full)
        result.append({"filename": f, "path": full, "size": stat.st_size, "mtime": stat.st_mtime})
    return result


def write_meeting_docs(
    aligned_segments: list[tuple[str, str]],
    summary: str,
    speakers: list[str],
    duration_min: int,
    output_dir: str,
    dt: "datetime | None" = None,
) -> dict[str, str]:
    """Write index, transkript, and zusammenfassung. Returns {type: path}."""
    if dt is None:
        dt = datetime.now()
    os.makedirs(output_dir, exist_ok=True)
    base = dt.strftime("%Y-%m-%d-%H%M") + "-meeting"
    date_str = dt.strftime("%d.%m.%Y %H:%M")
    frontmatter_base = f"---\ndate: {dt.isoformat(timespec='seconds')}\ntags: [transkript, meeting]\n---\n\n"

    # --- transkript ---
    transcript_lines = []
    for speaker, text in aligned_segments:
        transcript_lines.append(f"**{speaker}:** {text}\n")
    transcript_content = "\n".join(transcript_lines)
    transkript_filename = f"{base}-transkript.md"
    transkript_path = os.path.join(output_dir, transkript_filename)
    with open(transkript_path, "w", encoding="utf-8") as f:
        f.write(frontmatter_base)
        f.write(transcript_content)
        if not transcript_content.endswith("\n"):
            f.write("\n")

    # --- zusammenfassung ---
    zusammenfassung_filename = f"{base}-zusammenfassung.md"
    zusammenfassung_path = os.path.join(output_dir, zusammenfassung_filename)
    with open(zusammenfassung_path, "w", encoding="utf-8") as f:
        f.write(frontmatter_base)
        f.write(summary)
        if not summary.endswith("\n"):
            f.write("\n")

    # --- index ---
    speaker_str = ", ".join(speakers) if speakers else "Unbekannt"
    tl_dr = _extract_tldr(summary)
    index_content = (
        f"# Meeting — {date_str}\n\n"
        f"**Sprecher:** {speaker_str}  \n"
        f"**Dauer:** {duration_min} min\n\n"
        f"> {tl_dr}\n\n"
        f"- [Transkript]({transkript_filename})\n"
        f"- [Zusammenfassung]({zusammenfassung_filename})\n"
    )
    index_filename = f"{base}-index.md"
    index_path = os.path.join(output_dir, index_filename)
    with open(index_path, "w", encoding="utf-8") as f:
        f.write(f"---\ndate: {dt.isoformat(timespec='seconds')}\ntags: [transkript, meeting, index]\n---\n\n")
        f.write(index_content)

    return {"index": index_path, "transkript": transkript_path, "zusammenfassung": zusammenfassung_path}


def _extract_tldr(summary: str) -> str:
    """Return the first non-heading, non-empty line from the summary as TL;DR."""
    for line in summary.splitlines():
        stripped = line.strip()
        if stripped and not stripped.startswith("#"):
            return stripped[:200]
    return "Kein TL;DR verfügbar."