"""
fission_package_exporter.py — 裂变笔记包下载

把 FissionNote 表中的 N 套裂变结果打成 zip：
note_01/文案.txt + 生成图 + 发布清单 + 说明。
"""
from __future__ import annotations

import json
import logging
import shutil
import zipfile
from datetime import datetime
from pathlib import Path
from typing import Any

from app.core.config import get_settings

logger = logging.getLogger(__name__)


def _safe_name(value: str | None, fallback: str = "img") -> str:
    raw = (value or fallback).strip() or fallback
    return "".join(c if c.isalnum() or c in ("-", "_") else "_" for c in raw)[:40]


def _resolve_upload_path(url: str, upload_root: Path) -> Path:
    if url.startswith("/uploads/"):
        return upload_root / url.removeprefix("/uploads/")
    if url.startswith("uploads/"):
        return upload_root / url.removeprefix("uploads/")
    return Path(url)


def _loads_json(value: str | None, fallback: Any) -> Any:
    try:
        return json.loads(value) if value else fallback
    except (TypeError, ValueError):
        return fallback


def _write_note_text(note_dir: Path, note: dict[str, Any]) -> None:
    tags = note.get("tags") or []
    if not isinstance(tags, list):
        tags = []
    image_plan = note.get("imagePlan") or []
    lines = [
        f"【标题】{note.get('title', '')}",
        "",
        "【封面钩子】",
        str(note.get("coverTitle") or ""),
        "",
        "【正文】",
        str(note.get("content") or ""),
    ]
    if tags:
        lines += ["", "【标签】", " ".join(str(t) for t in tags)]
    if image_plan:
        lines += ["", "【图片排版说明】"]
        for idx, plan in enumerate(image_plan, start=1):
            if not isinstance(plan, dict):
                continue
            parts = [
                f"{idx}. {plan.get('role') or f'图{idx}'}",
                f"标题：{plan.get('title') or ''}",
                f"叠字：{plan.get('overlayText') or ''}",
                f"画面：{plan.get('text') or ''}",
            ]
            lines.append(" / ".join(parts))
    (note_dir / "文案.txt").write_text("\n".join(lines), encoding="utf-8")


def build_fission_package(ft, rows: list) -> str:
    """生成裂变下载 zip，返回 zip 本地路径。"""
    upload_root = Path(get_settings().UPLOAD_ABS_ROOT).resolve()
    package_dir = upload_root / "packages" / "fission" / str(ft.workspace_id) / str(ft.id)
    if package_dir.exists():
        shutil.rmtree(package_dir)
    package_dir.mkdir(parents=True, exist_ok=True)

    note_dirs: list[Path] = []
    checklist: list[str] = [
        "📋 裂变笔记发布清单",
        f"生成时间：{datetime.now().strftime('%Y-%m-%d %H:%M')}",
        f"裂变ID：{ft.id}",
        f"参考程度：{ft.reference_level}",
        "",
    ]
    missing_images: list[str] = []

    for idx, row in enumerate(rows, start=1):
        note = _loads_json(row.note_json, {})
        images = _loads_json(row.images_json, [])
        if not isinstance(note, dict):
            note = {}
        if not isinstance(images, list):
            images = []

        note_dir = package_dir / f"note_{idx:02d}"
        note_dir.mkdir(parents=True, exist_ok=True)
        note_dirs.append(note_dir)
        _write_note_text(note_dir, note)

        copied = 0
        expected = 0
        for img_idx, img in enumerate(images, start=1):
            if not isinstance(img, dict) or img.get("error"):
                continue
            url = img.get("url") or img.get("image_url")
            if not url:
                continue
            expected += 1
            src = _resolve_upload_path(str(url), upload_root)
            if not src.is_file():
                missing_images.append(f"note_{idx:02d}: {url}")
                continue
            role = _safe_name(str(img.get("role") or f"img_{img_idx}"))
            seq = img.get("seq") or img_idx
            dst = note_dir / f"{int(seq):02d}_{role}.jpg"
            shutil.copyfile(src, dst)
            copied += 1

        if expected and copied == 0:
            raise ValueError(f"第 {idx} 套裂变图片读取失败，拒绝生成无图下载包")

        title = str(note.get("title") or f"第{idx}套")
        checklist.append(
            f"note_{idx:02d}  标题：{title[:32]}  图片数：{copied}  分数：{row.score}"
        )

    if not note_dirs:
        raise ValueError("裂变结果为空，无法下载")

    if missing_images:
        checklist += ["", "图片读取提示："]
        checklist += [f"- {item}" for item in missing_images[:20]]
        if len(missing_images) > 20:
            checklist.append(f"- 另有 {len(missing_images) - 20} 张图片缺失")
    checklist += [
        "",
        "使用说明：",
        "- 每个 note_xx 文件夹是一套可独立发布的裂变笔记。",
        "- 文案.txt 内含标题、封面钩子、正文、标签和图片排版说明。",
        "- 图片按 01/02/03 顺序上传，避免传错序。",
    ]
    (package_dir / "📋裂变发布清单.txt").write_text("\n".join(checklist), encoding="utf-8")

    zip_path = package_dir / "fission_package.zip"
    with zipfile.ZipFile(zip_path, "w", zipfile.ZIP_DEFLATED) as zf:
        for note_dir in note_dirs:
            for fpath in sorted(note_dir.iterdir()):
                zf.write(fpath, arcname=f"{note_dir.name}/{fpath.name}")
        zf.write(package_dir / "📋裂变发布清单.txt", arcname="📋裂变发布清单.txt")

    logger.info("fission package built: %s notes=%d", zip_path, len(note_dirs))
    return str(zip_path)