"""SQLite database for bookmarks, sites, and cache metadata."""

from __future__ import annotations

import sqlite3
import json
import threading
from dataclasses import dataclass, field
from datetime import datetime, timezone
from pathlib import Path
from typing import Generator

from .config import db_path

_SCHEMA = """
CREATE TABLE IF NOT EXISTS sites (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    name        TEXT    NOT NULL UNIQUE,
    url         TEXT    NOT NULL,
    api_type    TEXT    NOT NULL,  -- danbooru | gelbooru | moebooru
    api_key     TEXT,
    api_user    TEXT,
    enabled     INTEGER NOT NULL DEFAULT 1,
    added_at    TEXT    NOT NULL
);

CREATE TABLE IF NOT EXISTS favorites (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    site_id     INTEGER NOT NULL REFERENCES sites(id),
    post_id     INTEGER NOT NULL,
    file_url    TEXT    NOT NULL,
    preview_url TEXT,
    tags        TEXT    NOT NULL DEFAULT '',
    rating      TEXT,
    score       INTEGER,
    source      TEXT,
    cached_path TEXT,
    folder      TEXT,
    favorited_at TEXT   NOT NULL,
    UNIQUE(site_id, post_id)
);

CREATE INDEX IF NOT EXISTS idx_favorites_tags ON favorites(tags);
CREATE INDEX IF NOT EXISTS idx_favorites_site ON favorites(site_id);
CREATE INDEX IF NOT EXISTS idx_favorites_folder ON favorites(folder);
CREATE INDEX IF NOT EXISTS idx_favorites_favorited_at ON favorites(favorited_at DESC);

CREATE TABLE IF NOT EXISTS favorite_folders (
    id   INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL UNIQUE
);

CREATE TABLE IF NOT EXISTS blacklisted_tags (
    id   INTEGER PRIMARY KEY AUTOINCREMENT,
    tag  TEXT NOT NULL UNIQUE
);

CREATE TABLE IF NOT EXISTS blacklisted_posts (
    id   INTEGER PRIMARY KEY AUTOINCREMENT,
    url  TEXT NOT NULL UNIQUE
);

CREATE TABLE IF NOT EXISTS library_meta (
    post_id        INTEGER PRIMARY KEY,
    tags           TEXT NOT NULL DEFAULT '',
    tag_categories TEXT DEFAULT '',
    score          INTEGER DEFAULT 0,
    rating         TEXT,
    source         TEXT,
    file_url       TEXT,
    saved_at       TEXT
);

CREATE TABLE IF NOT EXISTS settings (
    key   TEXT PRIMARY KEY,
    value TEXT NOT NULL
);

CREATE TABLE IF NOT EXISTS search_history (
    id        INTEGER PRIMARY KEY AUTOINCREMENT,
    query     TEXT NOT NULL,
    site_id   INTEGER,
    searched_at TEXT NOT NULL
);

CREATE TABLE IF NOT EXISTS saved_searches (
    id    INTEGER PRIMARY KEY AUTOINCREMENT,
    name  TEXT NOT NULL,
    query TEXT NOT NULL,
    site_id INTEGER
);
"""

_DEFAULTS = {
    "max_cache_mb": "2048",
    "auto_evict": "1",
    "thumbnail_size": "180",
    "page_size": "40",
    "default_rating": "all",
    "default_score": "0",
    "confirm_favorites": "0",
    "preload_thumbnails": "1",
    "file_dialog_platform": "qt",
    "blacklist_enabled": "1",
    "prefetch_adjacent": "0",
    "clear_cache_on_exit": "0",
    "slideshow_monitor": "",
    "library_dir": "",
    "infinite_scroll": "0",
}


@dataclass
class Site:
    id: int
    name: str
    url: str
    api_type: str
    api_key: str | None = None
    api_user: str | None = None
    enabled: bool = True


@dataclass
class Bookmark:
    id: int
    site_id: int
    post_id: int
    file_url: str
    preview_url: str | None
    tags: str
    rating: str | None
    score: int | None
    source: str | None
    cached_path: str | None
    folder: str | None
    bookmarked_at: str
    tag_categories: dict = field(default_factory=dict)


# Back-compat alias — will be removed in a future version.
Favorite = Bookmark


class Database:
    def __init__(self, path: Path | None = None) -> None:
        self._path = path or db_path()
        self._conn: sqlite3.Connection | None = None

    @property
    def conn(self) -> sqlite3.Connection:
        if self._conn is None:
            self._conn = sqlite3.connect(str(self._path), check_same_thread=False)
            self._conn.row_factory = sqlite3.Row
            self._conn.execute("PRAGMA journal_mode=WAL")
            self._conn.execute("PRAGMA foreign_keys=ON")
            self._conn.executescript(_SCHEMA)
            self._migrate()
        return self._conn

    def _migrate(self) -> None:
        """Add columns that may not exist in older databases."""
        cur = self._conn.execute("PRAGMA table_info(favorites)")
        cols = {row[1] for row in cur.fetchall()}
        if "folder" not in cols:
            self._conn.execute("ALTER TABLE favorites ADD COLUMN folder TEXT")
            self._conn.commit()
        self._conn.execute("CREATE INDEX IF NOT EXISTS idx_favorites_folder ON favorites(folder)")
        # Add tag_categories to library_meta if missing
        tables = {r[0] for r in self._conn.execute("SELECT name FROM sqlite_master WHERE type='table'").fetchall()}
        if "library_meta" in tables:
            cur = self._conn.execute("PRAGMA table_info(library_meta)")
            meta_cols = {row[1] for row in cur.fetchall()}
            if "tag_categories" not in meta_cols:
                self._conn.execute("ALTER TABLE library_meta ADD COLUMN tag_categories TEXT DEFAULT ''")
                self._conn.commit()
        # Add tag_categories to favorites if missing
        if "tag_categories" not in cols:
            self._conn.execute("ALTER TABLE favorites ADD COLUMN tag_categories TEXT DEFAULT ''")
            self._conn.commit()

    def close(self) -> None:
        if self._conn:
            self._conn.close()
            self._conn = None

    # -- Sites --

    def add_site(
        self,
        name: str,
        url: str,
        api_type: str,
        api_key: str | None = None,
        api_user: str | None = None,
    ) -> Site:
        now = datetime.now(timezone.utc).isoformat()
        cur = self.conn.execute(
            "INSERT INTO sites (name, url, api_type, api_key, api_user, added_at) "
            "VALUES (?, ?, ?, ?, ?, ?)",
            (name, url.rstrip("/"), api_type, api_key, api_user, now),
        )
        self.conn.commit()
        return Site(
            id=cur.lastrowid,  # type: ignore[arg-type]
            name=name,
            url=url.rstrip("/"),
            api_type=api_type,
            api_key=api_key,
            api_user=api_user,
        )

    def get_sites(self, enabled_only: bool = True) -> list[Site]:
        q = "SELECT * FROM sites"
        if enabled_only:
            q += " WHERE enabled = 1"
        q += " ORDER BY name"
        rows = self.conn.execute(q).fetchall()
        return [
            Site(
                id=r["id"],
                name=r["name"],
                url=r["url"],
                api_type=r["api_type"],
                api_key=r["api_key"],
                api_user=r["api_user"],
                enabled=bool(r["enabled"]),
            )
            for r in rows
        ]

    def delete_site(self, site_id: int) -> None:
        self.conn.execute("DELETE FROM favorites WHERE site_id = ?", (site_id,))
        self.conn.execute("DELETE FROM sites WHERE id = ?", (site_id,))
        self.conn.commit()

    def update_site(self, site_id: int, **fields: str | None) -> None:
        allowed = {"name", "url", "api_type", "api_key", "api_user", "enabled"}
        sets = []
        vals = []
        for k, v in fields.items():
            if k not in allowed:
                continue
            sets.append(f"{k} = ?")
            vals.append(v)
        if not sets:
            return
        vals.append(site_id)
        self.conn.execute(
            f"UPDATE sites SET {', '.join(sets)} WHERE id = ?", vals
        )
        self.conn.commit()

    # -- Bookmarks --

    def add_bookmark(
        self,
        site_id: int,
        post_id: int,
        file_url: str,
        preview_url: str | None,
        tags: str,
        rating: str | None = None,
        score: int | None = None,
        source: str | None = None,
        cached_path: str | None = None,
        folder: str | None = None,
        tag_categories: dict | None = None,
    ) -> Bookmark:
        now = datetime.now(timezone.utc).isoformat()
        cats_json = json.dumps(tag_categories) if tag_categories else ""
        cur = self.conn.execute(
            "INSERT OR IGNORE INTO favorites "
            "(site_id, post_id, file_url, preview_url, tags, rating, score, source, cached_path, folder, favorited_at, tag_categories) "
            "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
            (site_id, post_id, file_url, preview_url, tags, rating, score, source, cached_path, folder, now, cats_json),
        )
        self.conn.commit()
        return Bookmark(
            id=cur.lastrowid,  # type: ignore[arg-type]
            site_id=site_id,
            post_id=post_id,
            file_url=file_url,
            preview_url=preview_url,
            tags=tags,
            rating=rating,
            score=score,
            source=source,
            cached_path=cached_path,
            folder=folder,
            bookmarked_at=now,
        )

    # Back-compat shim
    add_favorite = add_bookmark

    def add_bookmarks_batch(self, bookmarks: list[dict]) -> None:
        """Add multiple bookmarks in a single transaction."""
        for fav in bookmarks:
            self.conn.execute(
                "INSERT OR IGNORE INTO favorites "
                "(site_id, post_id, file_url, preview_url, tags, rating, score, source, cached_path, folder, favorited_at) "
                "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
                (fav['site_id'], fav['post_id'], fav['file_url'], fav.get('preview_url'),
                 fav.get('tags', ''), fav.get('rating'), fav.get('score'), fav.get('source'),
                 fav.get('cached_path'), fav.get('folder'), fav.get('favorited_at', datetime.now(timezone.utc).isoformat())),
            )
        self.conn.commit()

    # Back-compat shim
    add_favorites_batch = add_bookmarks_batch

    def remove_bookmark(self, site_id: int, post_id: int) -> None:
        self.conn.execute(
            "DELETE FROM favorites WHERE site_id = ? AND post_id = ?",
            (site_id, post_id),
        )
        self.conn.commit()

    # Back-compat shim
    remove_favorite = remove_bookmark

    def is_bookmarked(self, site_id: int, post_id: int) -> bool:
        row = self.conn.execute(
            "SELECT 1 FROM favorites WHERE site_id = ? AND post_id = ?",
            (site_id, post_id),
        ).fetchone()
        return row is not None

    # Back-compat shim
    is_favorited = is_bookmarked

    def get_bookmarks(
        self,
        search: str | None = None,
        site_id: int | None = None,
        folder: str | None = None,
        limit: int = 100,
        offset: int = 0,
    ) -> list[Bookmark]:
        q = "SELECT * FROM favorites WHERE 1=1"
        params: list = []
        if site_id is not None:
            q += " AND site_id = ?"
            params.append(site_id)
        if folder is not None:
            q += " AND folder = ?"
            params.append(folder)
        if search:
            for tag in search.strip().split():
                q += " AND tags LIKE ?"
                params.append(f"%{tag}%")
        q += " ORDER BY favorited_at DESC LIMIT ? OFFSET ?"
        params.extend([limit, offset])
        rows = self.conn.execute(q, params).fetchall()
        return [self._row_to_bookmark(r) for r in rows]

    # Back-compat shim
    get_favorites = get_bookmarks

    @staticmethod
    def _row_to_bookmark(r) -> Bookmark:
        cats_raw = r["tag_categories"] if "tag_categories" in r.keys() else ""
        cats = json.loads(cats_raw) if cats_raw else {}
        return Bookmark(
            id=r["id"],
            site_id=r["site_id"],
            post_id=r["post_id"],
            file_url=r["file_url"],
            preview_url=r["preview_url"] if "preview_url" in r.keys() else None,
            tags=r["tags"],
            rating=r["rating"],
            score=r["score"],
            source=r["source"],
            cached_path=r["cached_path"],
            folder=r["folder"] if "folder" in r.keys() else None,
            bookmarked_at=r["favorited_at"],
            tag_categories=cats,
        )

    # Back-compat shim
    _row_to_favorite = _row_to_bookmark

    def update_bookmark_cache_path(self, fav_id: int, cached_path: str) -> None:
        self.conn.execute(
            "UPDATE favorites SET cached_path = ? WHERE id = ?",
            (cached_path, fav_id),
        )
        self.conn.commit()

    # Back-compat shim
    update_favorite_cache_path = update_bookmark_cache_path

    def bookmark_count(self) -> int:
        row = self.conn.execute("SELECT COUNT(*) FROM favorites").fetchone()
        return row[0]

    # Back-compat shim
    favorite_count = bookmark_count

    # -- Folders --

    def get_folders(self) -> list[str]:
        rows = self.conn.execute("SELECT name FROM favorite_folders ORDER BY name").fetchall()
        return [r["name"] for r in rows]

    def add_folder(self, name: str) -> None:
        self.conn.execute(
            "INSERT OR IGNORE INTO favorite_folders (name) VALUES (?)", (name.strip(),)
        )
        self.conn.commit()

    def remove_folder(self, name: str) -> None:
        self.conn.execute(
            "UPDATE favorites SET folder = NULL WHERE folder = ?", (name,)
        )
        self.conn.execute("DELETE FROM favorite_folders WHERE name = ?", (name,))
        self.conn.commit()

    def rename_folder(self, old: str, new: str) -> None:
        self.conn.execute(
            "UPDATE favorites SET folder = ? WHERE folder = ?", (new.strip(), old)
        )
        self.conn.execute(
            "UPDATE favorite_folders SET name = ? WHERE name = ?", (new.strip(), old)
        )
        self.conn.commit()

    def move_bookmark_to_folder(self, fav_id: int, folder: str | None) -> None:
        self.conn.execute(
            "UPDATE favorites SET folder = ? WHERE id = ?", (folder, fav_id)
        )
        self.conn.commit()

    # Back-compat shim
    move_favorite_to_folder = move_bookmark_to_folder

    # -- Blacklist --

    def add_blacklisted_tag(self, tag: str) -> None:
        self.conn.execute(
            "INSERT OR IGNORE INTO blacklisted_tags (tag) VALUES (?)",
            (tag.strip().lower(),),
        )
        self.conn.commit()

    def remove_blacklisted_tag(self, tag: str) -> None:
        self.conn.execute(
            "DELETE FROM blacklisted_tags WHERE tag = ?",
            (tag.strip().lower(),),
        )
        self.conn.commit()

    def get_blacklisted_tags(self) -> list[str]:
        rows = self.conn.execute("SELECT tag FROM blacklisted_tags ORDER BY tag").fetchall()
        return [r["tag"] for r in rows]

    # -- Blacklisted Posts --

    def add_blacklisted_post(self, url: str) -> None:
        self.conn.execute("INSERT OR IGNORE INTO blacklisted_posts (url) VALUES (?)", (url,))
        self.conn.commit()

    def remove_blacklisted_post(self, url: str) -> None:
        self.conn.execute("DELETE FROM blacklisted_posts WHERE url = ?", (url,))
        self.conn.commit()

    def get_blacklisted_posts(self) -> set[str]:
        rows = self.conn.execute("SELECT url FROM blacklisted_posts").fetchall()
        return {r["url"] for r in rows}

    # -- Library Metadata --

    def save_library_meta(self, post_id: int, tags: str = "", tag_categories: dict = None,
                          score: int = 0, rating: str = None, source: str = None,
                          file_url: str = None) -> None:
        cats_json = json.dumps(tag_categories) if tag_categories else ""
        self.conn.execute(
            "INSERT OR REPLACE INTO library_meta "
            "(post_id, tags, tag_categories, score, rating, source, file_url, saved_at) "
            "VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
            (post_id, tags, cats_json, score, rating, source, file_url,
             datetime.now(timezone.utc).isoformat()),
        )
        self.conn.commit()

    def get_library_meta(self, post_id: int) -> dict | None:
        row = self.conn.execute("SELECT * FROM library_meta WHERE post_id = ?", (post_id,)).fetchone()
        if not row:
            return None
        d = dict(row)
        cats = d.get("tag_categories", "")
        d["tag_categories"] = json.loads(cats) if cats else {}
        return d

    def search_library_meta(self, query: str) -> set[int]:
        """Search library metadata by tags. Returns matching post IDs."""
        rows = self.conn.execute(
            "SELECT post_id FROM library_meta WHERE tags LIKE ?",
            (f"%{query}%",),
        ).fetchall()
        return {r["post_id"] for r in rows}

    def remove_library_meta(self, post_id: int) -> None:
        self.conn.execute("DELETE FROM library_meta WHERE post_id = ?", (post_id,))
        self.conn.commit()

    # -- Settings --

    def get_setting(self, key: str) -> str:
        row = self.conn.execute("SELECT value FROM settings WHERE key = ?", (key,)).fetchone()
        if row:
            return row["value"]
        return _DEFAULTS.get(key, "")

    def get_setting_int(self, key: str) -> int:
        return int(self.get_setting(key) or "0")

    def get_setting_bool(self, key: str) -> bool:
        return self.get_setting(key) == "1"

    def set_setting(self, key: str, value: str) -> None:
        self.conn.execute(
            "INSERT OR REPLACE INTO settings (key, value) VALUES (?, ?)",
            (key, str(value)),
        )
        self.conn.commit()

    def get_all_settings(self) -> dict[str, str]:
        result = dict(_DEFAULTS)
        rows = self.conn.execute("SELECT key, value FROM settings").fetchall()
        for r in rows:
            result[r["key"]] = r["value"]
        return result

    # -- Search History --

    def add_search_history(self, query: str, site_id: int | None = None) -> None:
        if not query.strip():
            return
        now = datetime.now(timezone.utc).isoformat()
        # Remove duplicate if exists, keep latest
        self.conn.execute(
            "DELETE FROM search_history WHERE query = ? AND (site_id = ? OR (site_id IS NULL AND ? IS NULL))",
            (query.strip(), site_id, site_id),
        )
        self.conn.execute(
            "INSERT INTO search_history (query, site_id, searched_at) VALUES (?, ?, ?)",
            (query.strip(), site_id, now),
        )
        # Keep only last 50
        self.conn.execute(
            "DELETE FROM search_history WHERE id NOT IN "
            "(SELECT id FROM search_history ORDER BY searched_at DESC LIMIT 50)"
        )
        self.conn.commit()

    def get_search_history(self, limit: int = 20) -> list[str]:
        rows = self.conn.execute(
            "SELECT DISTINCT query FROM search_history ORDER BY searched_at DESC LIMIT ?",
            (limit,),
        ).fetchall()
        return [r["query"] for r in rows]

    def clear_search_history(self) -> None:
        self.conn.execute("DELETE FROM search_history")
        self.conn.commit()

    def remove_search_history(self, query: str) -> None:
        self.conn.execute("DELETE FROM search_history WHERE query = ?", (query,))
        self.conn.commit()

    # -- Saved Searches --

    def add_saved_search(self, name: str, query: str, site_id: int | None = None) -> None:
        self.conn.execute(
            "INSERT OR REPLACE INTO saved_searches (name, query, site_id) VALUES (?, ?, ?)",
            (name.strip(), query.strip(), site_id),
        )
        self.conn.commit()

    def get_saved_searches(self) -> list[tuple[int, str, str]]:
        """Returns list of (id, name, query)."""
        rows = self.conn.execute(
            "SELECT id, name, query FROM saved_searches ORDER BY name"
        ).fetchall()
        return [(r["id"], r["name"], r["query"]) for r in rows]

    def remove_saved_search(self, search_id: int) -> None:
        self.conn.execute("DELETE FROM saved_searches WHERE id = ?", (search_id,))
        self.conn.commit()