# ============================================================
# File: scraper/services/audio_completion.py
# Purpose:
#   Orchestration hook after audio completion.
#
# Rules (STRICT):
#   - ALWAYS read via get_book_state()
#   - Use ONLY merged counters from repository
#   - NO usage of derived status field
#   - Completion rule:
#         audio_completed < chapters_total  → NOT DONE
# ============================================================

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

from db.repository import (
    get_book_state,
    try_trigger_statuscheck,
)

from scraper.services.status_check_service import StatusCheckService
from scraper.tasks.m4b_tasks import queue_m4b_for_book


@logcall
def trigger_audio_completion_check(book_idx: str):
    """
    Called after inc_audio_done() OR inc_audio_skipped().

    Flow:
      1. Fetch canonical merged state from repository
      2. Evaluate completion via merged counters ONLY
      3. Run filesystem validation (authoritative)
      4. Apply idempotency guard
      5. Queue m4b exactly once
    """

    try:
        # ----------------------------------------------------
        # STEP 1 — CANONICAL MERGED STATE
        # ----------------------------------------------------
        state = get_book_state(book_idx)

        chapters_total = int(state.get("chapters_total", 0))
        audio_done = int(state.get("audio_done", 0))
        audio_skipped = int(state.get("audio_skipped", 0))
        audio_completed = audio_done + audio_skipped

        log(
            f"[AUDIO-COMPLETION] book={book_idx} "
            f"audio_completed={audio_completed} chapters_total={chapters_total}"
        )

        # ----------------------------------------------------
        # STEP 2 — FAST REJECT (MERGED COUNTERS ONLY)
        # ----------------------------------------------------
        if chapters_total <= 0 or audio_completed < chapters_total:
            log(f"[AUDIO-COMPLETION] not yet complete for book={book_idx}")
            return

        # ----------------------------------------------------
        # STEP 3 — FILESYSTEM VALIDATION (AUTHORITATIVE)
        # ----------------------------------------------------
        result = StatusCheckService.run(book_idx)
        fs = result.get("filesystem", {})

        audio_files = fs.get("audio_files", 0)
        chapters_txt = fs.get("chapters_txt", 0)
        effective_audio = audio_files + audio_skipped

        if effective_audio < chapters_txt:
            log(
                f"[AUDIO-COMPLETION] FS validation failed "
                f"(audio_files={audio_files}, skipped={audio_skipped}, txt={chapters_txt})"
            )
            return

        # ----------------------------------------------------
        # STEP 4 — IDEMPOTENCY GUARD (AFTER FS CONFIRMATION)
        # ----------------------------------------------------
        if not try_trigger_statuscheck(book_idx):
            log(f"[AUDIO-COMPLETION] statuscheck already triggered for {book_idx}")
            return

        # ----------------------------------------------------
        # STEP 5 — FINAL ACTION
        # ----------------------------------------------------
        log(f"[AUDIO-COMPLETION] DONE → queue m4b for book={book_idx}")
        queue_m4b_for_book(book_idx)

    except Exception as exc:
        # MUST NEVER break audio workers
        log(f"[AUDIO-COMPLETION][ERROR] book={book_idx} error={exc}")