"""画廊服务：扫描 output/ 目录结构。

output/ 下的每个一级子目录 = 一个画廊，目录名 = 谁生成的图片（profile_name）。
"""

from __future__ import annotations

import json
from datetime import datetime
from pathlib import Path
from typing import Any

from .. import config, db
from ..providers import ProviderError


def _folder(profile_name: str) -> Path:
    if not config.PROFILE_RE.fullmatch(profile_name):
        raise ProviderError("无效的画廊名称", status=400)
    root = config.OUTPUT_DIR.resolve()
    folder = (root / profile_name).resolve()
    if not folder.is_relative_to(root):
        raise ProviderError("画廊路径超出输出目录", status=400)
    return folder


def _meta_by_file() -> dict[tuple[str, str], dict[str, Any]]:
    """从 generations 表建立 (profile, filename) → 元信息的索引。"""
    index: dict[tuple[str, str], dict[str, Any]] = {}
    with db.session() as conn:
        rows = conn.execute("SELECT * FROM generations ORDER BY created_at DESC").fetchall()
    for row in rows:
        try:
            files = json.loads(row["files"] or "[]")
        except ValueError:
            files = []
        for name in files:
            key = (row["profile_name"], name)
            index.setdefault(
                key,
                {
                    "model": row["model"],
                    "provider_name": row["provider_name"],
                    "created_at": row["created_at"],
                    "prompt": row["prompt"],
                },
            )
    return index


def _images_in(folder: Path) -> list[Path]:
    return sorted(
        (p for p in folder.iterdir() if p.is_file() and p.suffix.lower() in config.IMAGE_SUFFIXES),
        key=lambda p: p.stat().st_mtime,
        reverse=True,
    )


def list_galleries() -> list[dict[str, Any]]:
    config.ensure_dirs()
    meta = _meta_by_file()
    galleries: list[dict[str, Any]] = []
    for folder in sorted(config.OUTPUT_DIR.iterdir()):
        if not folder.is_dir():
            continue
        images = _images_in(folder)
        if not images:
            continue
        total_bytes = 0
        models: list[str] = []
        latest = 0.0
        for img in images:
            stat = img.stat()
            total_bytes += stat.st_size
            latest = max(latest, stat.st_mtime)
            info = meta.get((folder.name, img.name))
            if info and info["model"] and info["model"] not in models:
                models.append(info["model"])
        cover = images[0]
        galleries.append(
            {
                "name": folder.name,
                "count": len(images),
                "bytes": total_bytes,
                "updated_at": datetime.fromtimestamp(latest).strftime("%Y-%m-%d %H:%M"),
                "cover": f"/output/{folder.name}/{cover.name}",
                "models": models,
            }
        )
    galleries.sort(key=lambda g: g["updated_at"], reverse=True)
    return galleries


def list_gallery(profile_name: str) -> list[dict[str, Any]]:
    config.ensure_dirs()
    folder = _folder(profile_name)
    if not folder.is_dir():
        return []
    meta = _meta_by_file()
    items: list[dict[str, Any]] = []
    for img in _images_in(folder):
        stat = img.stat()
        info = meta.get((profile_name, img.name), {})
        items.append(
            {
                "profile_name": profile_name,
                "filename": img.name,
                "url": f"/output/{profile_name}/{img.name}",
                "bytes": stat.st_size,
                "model": info.get("model", "—"),
                "provider_name": info.get("provider_name", "—"),
                "prompt": info.get("prompt", ""),
                "created_at": info.get("created_at")
                or datetime.fromtimestamp(stat.st_mtime).strftime("%Y-%m-%d %H:%M"),
            }
        )
    return items


def delete_gallery_item(profile_name: str, filename: str) -> None:
    folder = _folder(profile_name)
    if Path(filename).name != filename or "\\" in filename:
        raise ProviderError("无效的文件名", status=400)
    target = folder / filename
    if not target.resolve().is_relative_to(folder):
        raise ProviderError("图片路径超出画廊目录", status=400)
    if not target.is_file():
        raise FileNotFoundError(f"文件不存在: {profile_name}/{filename}")
    target.unlink()
    # 同步 generations 记录
    with db.session() as conn:
        rows = conn.execute(
            "SELECT id, files FROM generations WHERE profile_name=?", (profile_name,)
        ).fetchall()
        for row in rows:
            try:
                files = json.loads(row["files"] or "[]")
            except ValueError:
                files = []
            if filename in files:
                files = [f for f in files if f != filename]
                conn.execute(
                    "UPDATE generations SET files=? WHERE id=?",
                    (json.dumps(files, ensure_ascii=False), row["id"]),
                )