# scraper/download_controller.py

from celery import group
from scraper.tasks.pipeline import build_chapter_pipeline
from logbus.publisher import log
import os


class DownloadController:
    """Coordinates parallel chapter pipelines, with optional volume splitting."""

    def __init__(self, scrape_result: dict):
        self.scrape_result = scrape_result
        self.title = scrape_result.get("title", "UnknownBook")
        self.chapters = scrape_result.get("chapters", [])

        # Base output dir from .env
        root = os.getenv("BOOKSCRAPER_OUTPUT_DIR", "output")

        # Volume size
        self.max_vol = int(os.getenv("MAX_VOL_SIZE", "200"))

        # Base directory for the whole book
        self.book_base = os.path.join(root, self.title)
        os.makedirs(self.book_base, exist_ok=True)

        # ------------------------------------------
        # FIXED: meta now includes book_url
        # ------------------------------------------
        self.meta = {
            "title": self.scrape_result.get("title"),
            "author": self.scrape_result.get("author"),
            "description": self.scrape_result.get("description"),
            "book_url": self.scrape_result.get("book_url"),
        }

    def get_volume_path(self, chapter_num: int) -> str:
        """Returns the correct volume directory based on chapter number."""
        vol_index = (chapter_num - 1) // self.max_vol + 1
        vol_name = f"Volume_{vol_index:03d}"
        vol_path = os.path.join(self.book_base, vol_name)
        os.makedirs(vol_path, exist_ok=True)
        return vol_path

    def start(self):
        log(f"[CTRL] Starting download pipeline for {self.title}")
        log(f"[CTRL] Chapters: {len(self.chapters)}")
        log(f"[CTRL] Output root: {self.book_base}")
        log(f"[CTRL] MAX_VOL_SIZE = {self.max_vol}")

        tasks = []

        for ch in self.chapters:
            chapter_num = ch["num"]
            chapter_url = ch["url"]

            vol_path = self.get_volume_path(chapter_num)

            tasks.append(
                build_chapter_pipeline(
                    chapter_num,
                    chapter_url,
                    vol_path,
                    self.meta,
                )
            )

        job_group = group(tasks)
        async_result = job_group.apply_async()

        log("[CTRL] Pipelines launched.")
        return async_result