"""
Database layer: schema, connection/transaction lifecycle, and all query functions.
No file I/O, no config, no business logic. All SQL lives here.
"""

import json
import sqlite3
import time
import uuid
from collections.abc import Iterator
from contextlib import contextmanager
from datetime import datetime
from pathlib import Path
from typing import Any

from mashumaro.codecs import BasicDecoder

from models import BookRow, CabinetRow, RoomRow, ShelfRow

DB_PATH = Path("data") / "books.db"

# ── Schema ─────────────────────────────────────────────────────────────────────

SCHEMA = """
CREATE TABLE IF NOT EXISTS rooms (
    id             TEXT PRIMARY KEY,
    name           TEXT NOT NULL,
    position       INTEGER NOT NULL DEFAULT 0,
    created_at     TEXT NOT NULL
);
CREATE TABLE IF NOT EXISTS cabinets (
    id                   TEXT PRIMARY KEY,
    room_id              TEXT NOT NULL REFERENCES rooms(id) ON DELETE CASCADE,
    name                 TEXT NOT NULL,
    photo_filename       TEXT,
    shelf_boundaries     TEXT DEFAULT NULL,
    ai_shelf_boundaries  TEXT DEFAULT NULL,
    position             INTEGER NOT NULL DEFAULT 0,
    created_at           TEXT NOT NULL
);
CREATE TABLE IF NOT EXISTS shelves (
    id                  TEXT PRIMARY KEY,
    cabinet_id          TEXT NOT NULL REFERENCES cabinets(id) ON DELETE CASCADE,
    name                TEXT NOT NULL,
    photo_filename      TEXT,
    book_boundaries     TEXT DEFAULT NULL,
    ai_book_boundaries  TEXT DEFAULT NULL,
    position            INTEGER NOT NULL DEFAULT 0,
    created_at          TEXT NOT NULL
);
CREATE TABLE IF NOT EXISTS books (
    id                   TEXT PRIMARY KEY,
    shelf_id             TEXT NOT NULL REFERENCES shelves(id) ON DELETE CASCADE,
    position             INTEGER NOT NULL DEFAULT 0,
    image_filename       TEXT,
    title                TEXT DEFAULT '',
    author               TEXT DEFAULT '',
    year                 TEXT DEFAULT '',
    isbn                 TEXT DEFAULT '',
    publisher            TEXT DEFAULT '',
    notes                TEXT DEFAULT '',
    raw_text             TEXT DEFAULT '',
    ai_title             TEXT DEFAULT '',
    ai_author            TEXT DEFAULT '',
    ai_year              TEXT DEFAULT '',
    ai_isbn              TEXT DEFAULT '',
    ai_publisher         TEXT DEFAULT '',
    identification_status TEXT DEFAULT 'unidentified',
    title_confidence     REAL DEFAULT 0,
    analyzed_at          TEXT,
    created_at           TEXT NOT NULL,
    candidates           TEXT DEFAULT NULL,
    ai_blocks            TEXT DEFAULT NULL
);
CREATE TABLE IF NOT EXISTS ai_log (
    id          TEXT PRIMARY KEY,
    ts          REAL NOT NULL,
    plugin_id   TEXT NOT NULL,
    entity_type TEXT NOT NULL,
    entity_id   TEXT NOT NULL,
    model       TEXT NOT NULL,
    request     TEXT NOT NULL DEFAULT '',
    status      TEXT NOT NULL DEFAULT 'running',
    response    TEXT NOT NULL DEFAULT '',
    duration_ms INTEGER NOT NULL DEFAULT 0
);
CREATE TABLE IF NOT EXISTS batch_queue (
    book_id  TEXT PRIMARY KEY,
    added_at REAL NOT NULL
);
"""

# ── Mashumaro decoders for entity rows ────────────────────────────────────────

_room_dec: BasicDecoder[RoomRow] = BasicDecoder(RoomRow)
_cabinet_dec: BasicDecoder[CabinetRow] = BasicDecoder(CabinetRow)
_shelf_dec: BasicDecoder[ShelfRow] = BasicDecoder(ShelfRow)
_book_dec: BasicDecoder[BookRow] = BasicDecoder(BookRow)


def _room(row: sqlite3.Row) -> RoomRow:
    return _room_dec.decode(dict(row))


def _cabinet(row: sqlite3.Row) -> CabinetRow:
    return _cabinet_dec.decode(dict(row))


def _shelf(row: sqlite3.Row) -> ShelfRow:
    return _shelf_dec.decode(dict(row))


def _book(row: sqlite3.Row) -> BookRow:
    return _book_dec.decode(dict(row))


# ── DB init + connection ────────────────────────────────────────────────────────


def init_db() -> None:
    DB_PATH.parent.mkdir(exist_ok=True)
    c = conn()
    c.executescript(SCHEMA)
    c.commit()
    c.close()


def conn() -> sqlite3.Connection:
    c = sqlite3.connect(DB_PATH)
    c.row_factory = sqlite3.Row
    c.execute("PRAGMA foreign_keys = ON")
    return c


# ── Context managers ──────────────────────────────────────────────────────────


@contextmanager
def connection() -> Iterator[sqlite3.Connection]:
    """Read-only context: opens a connection, closes on exit."""
    c = conn()
    try:
        yield c
    finally:
        c.close()


@contextmanager
def transaction() -> Iterator[sqlite3.Connection]:
    """Write context: opens, commits on success, rolls back on exception."""
    c = conn()
    try:
        yield c
        c.commit()
    except Exception:
        c.rollback()
        raise
    finally:
        c.close()


# ── Helpers ───────────────────────────────────────────────────────────────────

COUNTERS: dict[str, int] = {}


def uid() -> str:
    return str(uuid.uuid4())


def now() -> str:
    return datetime.now().isoformat()


def next_pos(db: sqlite3.Connection, table: str, parent_col: str, parent_id: str) -> int:
    row = db.execute(f"SELECT COALESCE(MAX(position),0)+1 FROM {table} WHERE {parent_col}=?", [parent_id]).fetchone()
    return int(row[0])


def next_root_pos(db: sqlite3.Connection, table: str) -> int:
    row = db.execute(f"SELECT COALESCE(MAX(position),0)+1 FROM {table}").fetchone()
    return int(row[0])


def next_name(prefix: str) -> str:
    COUNTERS[prefix] = COUNTERS.get(prefix, 0) + 1
    return f"{prefix} {COUNTERS[prefix]}"


# ── Tree ──────────────────────────────────────────────────────────────────────


def get_tree(db: sqlite3.Connection) -> list[dict[str, object]]:
    """Build and return the full nested Room→Cabinet→Shelf→Book tree."""
    rooms: list[dict[str, object]] = [dict(r) for r in db.execute("SELECT * FROM rooms ORDER BY position")]
    for room in rooms:
        cabs: list[dict[str, object]] = [
            dict(c) for c in db.execute("SELECT * FROM cabinets WHERE room_id=? ORDER BY position", [room["id"]])
        ]
        for cab in cabs:
            shelves: list[dict[str, object]] = [
                dict(s) for s in db.execute("SELECT * FROM shelves WHERE cabinet_id=? ORDER BY position", [cab["id"]])
            ]
            for shelf in shelves:
                shelf["books"] = [
                    dict(b) for b in db.execute("SELECT * FROM books WHERE shelf_id=? ORDER BY position", [shelf["id"]])
                ]
            cab["shelves"] = shelves
        room["cabinets"] = cabs
    return rooms


# ── Rooms ─────────────────────────────────────────────────────────────────────


def get_room(db: sqlite3.Connection, room_id: str) -> RoomRow | None:
    row = db.execute("SELECT * FROM rooms WHERE id=?", [room_id]).fetchone()
    return _room(row) if row else None


def create_room(db: sqlite3.Connection) -> RoomRow:
    data = {"id": uid(), "name": next_name("Room"), "position": next_root_pos(db, "rooms"), "created_at": now()}
    db.execute("INSERT INTO rooms VALUES(:id,:name,:position,:created_at)", data)
    return _room_dec.decode(data)


def rename_room(db: sqlite3.Connection, room_id: str, name: str) -> None:
    db.execute("UPDATE rooms SET name=? WHERE id=?", [name, room_id])


def collect_room_photos(db: sqlite3.Connection, room_id: str) -> list[str]:
    """Return all photo filenames for cabinets/shelves/books under this room."""
    photos: list[str] = []
    for r in db.execute(
        "SELECT image_filename FROM books WHERE shelf_id IN "
        "(SELECT id FROM shelves WHERE cabinet_id IN (SELECT id FROM cabinets WHERE room_id=?))",
        [room_id],
    ):
        if r[0]:
            photos.append(str(r[0]))
    for r in db.execute(
        "SELECT photo_filename FROM shelves WHERE cabinet_id IN (SELECT id FROM cabinets WHERE room_id=?)", [room_id]
    ):
        if r[0]:
            photos.append(str(r[0]))
    for r in db.execute("SELECT photo_filename FROM cabinets WHERE room_id=?", [room_id]):
        if r[0]:
            photos.append(str(r[0]))
    return photos


def delete_room(db: sqlite3.Connection, room_id: str) -> None:
    """Delete room; SQLite ON DELETE CASCADE removes all children."""
    db.execute("DELETE FROM rooms WHERE id=?", [room_id])


# ── Cabinets ──────────────────────────────────────────────────────────────────


def get_cabinet(db: sqlite3.Connection, cabinet_id: str) -> CabinetRow | None:
    row = db.execute("SELECT * FROM cabinets WHERE id=?", [cabinet_id]).fetchone()
    return _cabinet(row) if row else None


def create_cabinet(db: sqlite3.Connection, room_id: str) -> CabinetRow:
    data: dict[str, object] = {
        "id": uid(),
        "room_id": room_id,
        "name": next_name("Cabinet"),
        "photo_filename": None,
        "shelf_boundaries": None,
        "ai_shelf_boundaries": None,
        "position": next_pos(db, "cabinets", "room_id", room_id),
        "created_at": now(),
    }
    db.execute(
        "INSERT INTO cabinets VALUES("
        ":id,:room_id,:name,:photo_filename,:shelf_boundaries,"
        ":ai_shelf_boundaries,:position,:created_at)",
        data,
    )
    return _cabinet_dec.decode(data)


def rename_cabinet(db: sqlite3.Connection, cabinet_id: str, name: str) -> None:
    db.execute("UPDATE cabinets SET name=? WHERE id=?", [name, cabinet_id])


def collect_cabinet_photos(db: sqlite3.Connection, cabinet_id: str) -> list[str]:
    photos: list[str] = []
    for r in db.execute(
        "SELECT image_filename FROM books WHERE shelf_id IN (SELECT id FROM shelves WHERE cabinet_id=?)", [cabinet_id]
    ):
        if r[0]:
            photos.append(str(r[0]))
    for r in db.execute("SELECT photo_filename FROM shelves WHERE cabinet_id=?", [cabinet_id]):
        if r[0]:
            photos.append(str(r[0]))
    row = db.execute("SELECT photo_filename FROM cabinets WHERE id=?", [cabinet_id]).fetchone()
    if row and row[0]:
        photos.append(str(row[0]))
    return photos


def delete_cabinet(db: sqlite3.Connection, cabinet_id: str) -> None:
    db.execute("DELETE FROM cabinets WHERE id=?", [cabinet_id])


def get_cabinet_photo(db: sqlite3.Connection, cabinet_id: str) -> str | None:
    row = db.execute("SELECT photo_filename FROM cabinets WHERE id=?", [cabinet_id]).fetchone()
    return str(row[0]) if row and row[0] else None


def set_cabinet_photo(db: sqlite3.Connection, cabinet_id: str, filename: str) -> None:
    db.execute("UPDATE cabinets SET photo_filename=? WHERE id=?", [filename, cabinet_id])


def set_cabinet_boundaries(db: sqlite3.Connection, cabinet_id: str, boundaries_json: str) -> None:
    db.execute("UPDATE cabinets SET shelf_boundaries=? WHERE id=?", [boundaries_json, cabinet_id])


def set_ai_shelf_boundaries(db: sqlite3.Connection, cabinet_id: str, plugin_id: str, boundaries: list[float]) -> None:
    row = db.execute("SELECT ai_shelf_boundaries FROM cabinets WHERE id=?", [cabinet_id]).fetchone()
    current: dict[str, object] = json.loads(row[0]) if row and row[0] else {}
    current[plugin_id] = boundaries
    db.execute("UPDATE cabinets SET ai_shelf_boundaries=? WHERE id=?", [json.dumps(current), cabinet_id])


# ── Shelves ───────────────────────────────────────────────────────────────────


def get_shelf(db: sqlite3.Connection, shelf_id: str) -> ShelfRow | None:
    row = db.execute("SELECT * FROM shelves WHERE id=?", [shelf_id]).fetchone()
    return _shelf(row) if row else None


def create_shelf(db: sqlite3.Connection, cabinet_id: str) -> ShelfRow:
    data: dict[str, object] = {
        "id": uid(),
        "cabinet_id": cabinet_id,
        "name": next_name("Shelf"),
        "photo_filename": None,
        "book_boundaries": None,
        "ai_book_boundaries": None,
        "position": next_pos(db, "shelves", "cabinet_id", cabinet_id),
        "created_at": now(),
    }
    db.execute(
        "INSERT INTO shelves VALUES("
        ":id,:cabinet_id,:name,:photo_filename,:book_boundaries,:ai_book_boundaries,:position,:created_at)",
        data,
    )
    return _shelf_dec.decode(data)


def rename_shelf(db: sqlite3.Connection, shelf_id: str, name: str) -> None:
    db.execute("UPDATE shelves SET name=? WHERE id=?", [name, shelf_id])


def collect_shelf_photos(db: sqlite3.Connection, shelf_id: str) -> list[str]:
    photos: list[str] = []
    row = db.execute("SELECT photo_filename FROM shelves WHERE id=?", [shelf_id]).fetchone()
    if row and row[0]:
        photos.append(str(row[0]))
    for r in db.execute("SELECT image_filename FROM books WHERE shelf_id=?", [shelf_id]):
        if r[0]:
            photos.append(str(r[0]))
    return photos


def delete_shelf(db: sqlite3.Connection, shelf_id: str) -> None:
    db.execute("DELETE FROM shelves WHERE id=?", [shelf_id])


def get_shelf_photo(db: sqlite3.Connection, shelf_id: str) -> str | None:
    row = db.execute("SELECT photo_filename FROM shelves WHERE id=?", [shelf_id]).fetchone()
    return str(row[0]) if row and row[0] else None


def set_shelf_photo(db: sqlite3.Connection, shelf_id: str, filename: str) -> None:
    db.execute("UPDATE shelves SET photo_filename=? WHERE id=?", [filename, shelf_id])


def set_shelf_boundaries(db: sqlite3.Connection, shelf_id: str, boundaries_json: str) -> None:
    db.execute("UPDATE shelves SET book_boundaries=? WHERE id=?", [boundaries_json, shelf_id])


def set_ai_book_boundaries(db: sqlite3.Connection, shelf_id: str, plugin_id: str, boundaries: list[float]) -> None:
    row = db.execute("SELECT ai_book_boundaries FROM shelves WHERE id=?", [shelf_id]).fetchone()
    current: dict[str, object] = json.loads(row[0]) if row and row[0] else {}
    current[plugin_id] = boundaries
    db.execute("UPDATE shelves SET ai_book_boundaries=? WHERE id=?", [json.dumps(current), shelf_id])


def get_shelf_rank(db: sqlite3.Connection, shelf_id: str) -> int:
    """0-based rank of shelf among its siblings sorted by position."""
    row = db.execute("SELECT cabinet_id FROM shelves WHERE id=?", [shelf_id]).fetchone()
    if not row:
        return 0
    siblings = [r[0] for r in db.execute("SELECT id FROM shelves WHERE cabinet_id=? ORDER BY position", [row[0]])]
    return siblings.index(shelf_id) if shelf_id in siblings else 0


# ── Books ─────────────────────────────────────────────────────────────────────


def get_book(db: sqlite3.Connection, book_id: str) -> BookRow | None:
    row = db.execute("SELECT * FROM books WHERE id=?", [book_id]).fetchone()
    return _book(row) if row else None


def create_book(db: sqlite3.Connection, shelf_id: str) -> BookRow:
    data: dict[str, object] = {
        "id": uid(),
        "shelf_id": shelf_id,
        "position": next_pos(db, "books", "shelf_id", shelf_id),
        "image_filename": None,
        "title": "",
        "author": "",
        "year": "",
        "isbn": "",
        "publisher": "",
        "notes": "",
        "raw_text": "",
        "ai_title": "",
        "ai_author": "",
        "ai_year": "",
        "ai_isbn": "",
        "ai_publisher": "",
        "identification_status": "unidentified",
        "title_confidence": 0,
        "analyzed_at": None,
        "created_at": now(),
        "candidates": None,
        "ai_blocks": None,
    }
    db.execute(
        "INSERT INTO books VALUES(:id,:shelf_id,:position,:image_filename,:title,:author,:year,:isbn,:publisher,"
        ":notes,:raw_text,:ai_title,:ai_author,:ai_year,:ai_isbn,:ai_publisher,:identification_status,"
        ":title_confidence,:analyzed_at,:created_at,:candidates,:ai_blocks)",
        data,
    )
    return _book_dec.decode(data)


def delete_book(db: sqlite3.Connection, book_id: str) -> None:
    db.execute("DELETE FROM books WHERE id=?", [book_id])


def get_book_photo(db: sqlite3.Connection, book_id: str) -> str | None:
    row = db.execute("SELECT image_filename FROM books WHERE id=?", [book_id]).fetchone()
    return str(row[0]) if row and row[0] else None


def set_book_photo(db: sqlite3.Connection, book_id: str, filename: str) -> None:
    db.execute("UPDATE books SET image_filename=? WHERE id=?", [filename, book_id])


def set_user_book_fields(
    db: sqlite3.Connection,
    book_id: str,
    title: str,
    author: str,
    year: str,
    isbn: str,
    publisher: str,
    notes: str,
) -> None:
    """Set both user fields and ai_* fields (user edit is the authoritative identification)."""
    db.execute(
        "UPDATE books SET title=?,author=?,year=?,isbn=?,publisher=?,notes=?,"
        "ai_title=?,ai_author=?,ai_year=?,ai_isbn=?,ai_publisher=? WHERE id=?",
        [title, author, year, isbn, publisher, notes, title, author, year, isbn, publisher, book_id],
    )


def set_book_status(db: sqlite3.Connection, book_id: str, status: str) -> None:
    db.execute("UPDATE books SET identification_status=? WHERE id=?", [status, book_id])


def set_book_confidence(db: sqlite3.Connection, book_id: str, confidence: float, analyzed_at: str) -> None:
    db.execute(
        "UPDATE books SET title_confidence=?, analyzed_at=? WHERE id=?",
        [confidence, analyzed_at, book_id],
    )


def set_book_ai_fields(
    db: sqlite3.Connection,
    book_id: str,
    ai_title: str,
    ai_author: str,
    ai_year: str,
    ai_isbn: str,
    ai_publisher: str,
) -> None:
    db.execute(
        "UPDATE books SET ai_title=?,ai_author=?,ai_year=?,ai_isbn=?,ai_publisher=? WHERE id=?",
        [ai_title, ai_author, ai_year, ai_isbn, ai_publisher, book_id],
    )


def set_book_ai_field(db: sqlite3.Connection, book_id: str, field: str, value: str) -> None:
    """Set a single ai_* field by name (used in dismiss_field logic)."""
    # field is validated by caller to be in AI_FIELDS
    db.execute(f"UPDATE books SET ai_{field}=? WHERE id=?", [value, book_id])


def set_book_raw_text(db: sqlite3.Connection, book_id: str, raw_text: str) -> None:
    db.execute("UPDATE books SET raw_text=? WHERE id=?", [raw_text, book_id])


def set_book_candidates(db: sqlite3.Connection, book_id: str, candidates_json: str) -> None:
    db.execute("UPDATE books SET candidates=? WHERE id=?", [candidates_json, book_id])


def set_book_ai_blocks(db: sqlite3.Connection, book_id: str, ai_blocks_json: str) -> None:
    db.execute("UPDATE books SET ai_blocks=? WHERE id=?", [ai_blocks_json, book_id])


def get_book_rank(db: sqlite3.Connection, book_id: str) -> int:
    """0-based rank of book among its siblings sorted by position."""
    row = db.execute("SELECT shelf_id FROM books WHERE id=?", [book_id]).fetchone()
    if not row:
        return 0
    siblings = [r[0] for r in db.execute("SELECT id FROM books WHERE shelf_id=? ORDER BY position", [row[0]])]
    return siblings.index(book_id) if book_id in siblings else 0


def get_unidentified_book_ids(db: sqlite3.Connection) -> list[str]:
    return [str(r[0]) for r in db.execute("SELECT id FROM books WHERE identification_status='unidentified'")]


# ── Reorder ───────────────────────────────────────────────────────────────────


def reorder_entities(db: sqlite3.Connection, table: str, ids: list[str]) -> None:
    for i, entity_id in enumerate(ids, 1):
        db.execute(f"UPDATE {table} SET position=? WHERE id=?", [i, entity_id])


# ── AI log ────────────────────────────────────────────────────────────────────


def insert_ai_log_entry(
    db: sqlite3.Connection,
    entry_id: str,
    ts: float,
    plugin_id: str,
    entity_type: str,
    entity_id: str,
    model: str,
    request: str,
) -> None:
    """Insert a new AI log entry with status='running'."""
    db.execute(
        "INSERT OR IGNORE INTO ai_log"
        " (id, ts, plugin_id, entity_type, entity_id, model, request) VALUES (?,?,?,?,?,?,?)",
        [entry_id, ts, plugin_id, entity_type, entity_id, model, request],
    )


def update_ai_log_entry(db: sqlite3.Connection, entry_id: str, status: str, response: str, duration_ms: int) -> None:
    """Update an AI log entry with the final status and response."""
    db.execute(
        "UPDATE ai_log SET status=?, response=?, duration_ms=? WHERE id=?",
        [status, response, duration_ms, entry_id],
    )


def get_ai_log_entries(db: sqlite3.Connection, limit: int) -> list[dict[str, Any]]:
    """Return the most recent AI log entries, oldest first."""
    rows = db.execute(
        "SELECT id, ts, plugin_id, entity_type, entity_id, model, request, status, response, duration_ms"
        " FROM ai_log ORDER BY ts DESC LIMIT ?",
        [limit],
    ).fetchall()
    return [dict(r) for r in reversed(rows)]


# ── Batch queue ────────────────────────────────────────────────────────────────


def add_to_batch_queue(db: sqlite3.Connection, book_ids: list[str]) -> None:
    """Insert book IDs into the batch queue, ignoring duplicates.

    Args:
        db: Open database connection (must be writable).
        book_ids: Book IDs to enqueue.
    """
    ts = time.time()
    db.executemany(
        "INSERT OR IGNORE INTO batch_queue (book_id, added_at) VALUES (?,?)", [(bid, ts) for bid in book_ids]
    )


def remove_from_batch_queue(db: sqlite3.Connection, book_id: str) -> None:
    """Remove a single book ID from the batch queue.

    Args:
        db: Open database connection (must be writable).
        book_id: Book ID to dequeue.
    """
    db.execute("DELETE FROM batch_queue WHERE book_id=?", [book_id])


def get_batch_queue(db: sqlite3.Connection) -> list[str]:
    """Return all queued book IDs ordered by insertion time (oldest first).

    Args:
        db: Open database connection.

    Returns:
        List of book ID strings.
    """
    rows = db.execute("SELECT book_id FROM batch_queue ORDER BY added_at").fetchall()
    return [str(r[0]) for r in rows]


def clear_batch_queue(db: sqlite3.Connection) -> None:
    """Remove all entries from the batch queue.

    Args:
        db: Open database connection (must be writable).
    """
    db.execute("DELETE FROM batch_queue")