# ============================================================
# File: scraper/tasks/m4b_tasks.py
# ============================================================

import os
import subprocess
from typing import List

from celery_app import celery_app
from logbus.publisher import log
from scraper.logger_decorators import logcall

from db.repository import fetch_book, store_m4b_error
from scraper.scriptgen import build_merge_block


# ------------------------------------------------------------
# Helper: detect volumes (UNCHANGED)
# ------------------------------------------------------------
def detect_volumes(book_base: str) -> List[str]:
    volumes = []
    for name in os.listdir(book_base):
        if name.lower().startswith("volume_"):
            full = os.path.join(book_base, name)
            if os.path.isdir(full):
                volumes.append(name)
    volumes.sort()
    return volumes


# ------------------------------------------------------------
# Celery task
# ------------------------------------------------------------
@celery_app.task(bind=True, queue="m4b", ignore_result=True)
@logcall
def run_m4btool(self, book_idx: str):

    log(f"[M4B] START book_idx={book_idx}")

    book = fetch_book(book_idx)
    if not book:
        log(f"[M4B] Book not found in SQL: book_idx={book_idx}")
        return

    title = book.get("title", book_idx)
    author = book.get("author", "Unknown")

    output_root = os.getenv("BOOKSCRAPER_OUTPUT_DIR", "output")
    book_base = os.path.join(output_root, title)

    log(f"[M4B] Book base directory: {book_base}")

    if not os.path.isdir(book_base):
        log(f"[M4B] Book directory missing: {book_base}")
        return

    volumes = detect_volumes(book_base)
    if not volumes:
        log(f"[M4B] No volumes found for book_idx={book_idx}")
        return

    log(f"[M4B] Volumes detected: {volumes}")

    # --------------------------------------------------------
    # Build canonical commands via scriptgen
    # --------------------------------------------------------
    merge_block = build_merge_block(
        title, author, [(i + 1, v) for i, v in enumerate(volumes)]
    )
    commands = [c.strip() for c in merge_block.split("&&") if c.strip()]

    for volume, cmd in zip(volumes, commands):
        audio_dir = os.path.join(book_base, volume, "Audio")
        if not os.path.isdir(audio_dir):
            log(f"[M4B] SKIP {volume}: no Audio directory")
            continue

        log(f"[M4B] Running for volume={volume}")
        log(f"[M4B] CMD: {cmd}")

        try:
            result = subprocess.run(
                cmd,
                cwd=book_base,
                shell=True,
                capture_output=True,
                text=True,
                check=True,
            )

            if result.stdout:
                log(f"[M4B][STDOUT] {result.stdout}")

        except subprocess.CalledProcessError as exc:
            log(f"[M4B][FAILED] volume={volume}")

            if exc.stdout:
                log(f"[M4B][STDOUT] {exc.stdout}")
            if exc.stderr:
                log(f"[M4B][STDERR] {exc.stderr}")

            store_m4b_error(
                book_idx=book_idx,
                volume=volume,
                error_text=exc.stderr or str(exc),
            )
            continue

        except Exception as exc:
            log(f"[M4B][UNEXPECTED ERROR] volume={volume}: {exc}")

            store_m4b_error(
                book_idx=book_idx,
                volume=volume,
                error_text=str(exc),
            )
            continue

    log(f"[M4B] FINISHED book_idx={book_idx}")


# ------------------------------------------------------------
# Orchestration helper (UNCHANGED)
# ------------------------------------------------------------
@logcall
def queue_m4b_for_book(book_idx: str):
    log(f"[M4B] Queuing m4b-tool for book_idx={book_idx}")
    celery_app.send_task(
        "scraper.tasks.m4b_tasks.run_m4btool",
        args=[book_idx],
        queue="m4b",
    )