import aiosqlite
from config import DB_PATH

CREATE_TABLE = """
CREATE TABLE IF NOT EXISTS guides (
    id TEXT PRIMARY KEY,
    topic TEXT NOT NULL,
    format TEXT NOT NULL,
    instructions TEXT NOT NULL DEFAULT '',
    status TEXT NOT NULL DEFAULT 'queued',
    progress TEXT,
    error_msg TEXT,
    html_path TEXT,
    pdf_path TEXT,
    created_at TEXT NOT NULL,
    updated_at TEXT NOT NULL
)
"""

_db: aiosqlite.Connection | None = None


async def get_db() -> aiosqlite.Connection:
    global _db
    if _db is None:
        _db = await aiosqlite.connect(DB_PATH)
        _db.row_factory = None
    return _db


async def init_db():
    db = await get_db()
    await db.execute(CREATE_TABLE)
    cursor = await db.execute("PRAGMA table_info(guides)")
    columns = {row[1] for row in await cursor.fetchall()}
    if "instructions" not in columns:
        await db.execute("ALTER TABLE guides ADD COLUMN instructions TEXT NOT NULL DEFAULT ''")
    await db.execute(
        "UPDATE guides SET status = 'error', progress = NULL, error_msg = 'Server-Neustart' "
        "WHERE status IN ('queued', 'generating')"
    )
    await db.commit()


async def close_db():
    global _db
    if _db is not None:
        await _db.close()
        _db = None


def _row_to_dict(row, cursor):
    columns = [d[0] for d in cursor.description]
    return dict(zip(columns, row))


async def create_guide(guide: dict) -> dict:
    db = await get_db()
    await db.execute(
        """INSERT INTO guides (id, topic, format, instructions, status, progress, html_path, pdf_path, created_at, updated_at)
           VALUES (:id, :topic, :format, :instructions, :status, :progress, :html_path, :pdf_path, :created_at, :updated_at)""",
        guide,
    )
    await db.commit()
    return guide


async def get_guide(guide_id: str) -> dict | None:
    db = await get_db()
    cursor = await db.execute("SELECT * FROM guides WHERE id = ?", (guide_id,))
    row = await cursor.fetchone()
    if row is None:
        return None
    return _row_to_dict(row, cursor)


async def list_guides() -> list[dict]:
    db = await get_db()
    cursor = await db.execute("SELECT * FROM guides ORDER BY created_at DESC")
    rows = await cursor.fetchall()
    return [_row_to_dict(row, cursor) for row in rows]


async def update_guide(guide_id: str, **fields) -> None:
    sets = ", ".join(f"{k} = :{k}" for k in fields)
    fields["id"] = guide_id
    db = await get_db()
    await db.execute(f"UPDATE guides SET {sets} WHERE id = :id", fields)
    await db.commit()


async def delete_guide(guide_id: str) -> bool:
    db = await get_db()
    cursor = await db.execute("DELETE FROM guides WHERE id = ?", (guide_id,))
    await db.commit()
    return cursor.rowcount > 0