"""SQLite helpers."""

from __future__ import annotations

from collections.abc import AsyncIterator
from contextlib import asynccontextmanager
from pathlib import Path

import aiosqlite

SCHEMA = """
CREATE TABLE IF NOT EXISTS quizzes (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT NOT NULL,
    pool_json TEXT NOT NULL,
    time_limit_default INTEGER NOT NULL DEFAULT 60,
    score_fn_name TEXT NOT NULL DEFAULT 'linear_decay',
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS quiz_sessions (
    sid TEXT PRIMARY KEY,
    quiz_id INTEGER NOT NULL REFERENCES quizzes(id),
    title TEXT NOT NULL,
    state TEXT NOT NULL DEFAULT 'lobby',
    current_question_idx INTEGER,
    started_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    finished_at TIMESTAMP
);

CREATE TABLE IF NOT EXISTS participants (
    sid TEXT NOT NULL REFERENCES quiz_sessions(sid),
    student_id TEXT NOT NULL,
    name TEXT NOT NULL,
    cookie_id TEXT NOT NULL,
    joined_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (sid, student_id)
);

CREATE TABLE IF NOT EXISTS question_events (
    sid TEXT NOT NULL REFERENCES quiz_sessions(sid),
    question_idx INTEGER NOT NULL,
    opened_at TIMESTAMP NOT NULL,
    closed_at TIMESTAMP,
    time_limit INTEGER NOT NULL,
    PRIMARY KEY (sid, question_idx)
);

CREATE TABLE IF NOT EXISTS submissions (
    sid TEXT NOT NULL REFERENCES quiz_sessions(sid),
    student_id TEXT NOT NULL,
    question_idx INTEGER NOT NULL,
    answer TEXT,
    submitted_at TIMESTAMP,
    elapsed_ms INTEGER,
    score INTEGER NOT NULL DEFAULT 0,
    status TEXT NOT NULL DEFAULT 'submitted',
    PRIMARY KEY (sid, student_id, question_idx)
);

CREATE INDEX IF NOT EXISTS idx_submissions_sid_qidx ON submissions(sid, question_idx);
CREATE INDEX IF NOT EXISTS idx_participants_sid ON participants(sid);
"""


async def init_db(db_path: str) -> None:
    if db_path != ":memory:":
        Path(db_path).parent.mkdir(parents=True, exist_ok=True)
    async with connect(db_path) as db:
        await db.executescript(SCHEMA)
        await db.commit()


@asynccontextmanager
async def connect(db_path: str) -> AsyncIterator[aiosqlite.Connection]:
    db = await aiosqlite.connect(db_path)
    db.row_factory = aiosqlite.Row
    await db.execute("PRAGMA foreign_keys=ON")
    await db.execute("PRAGMA journal_mode=WAL")
    try:
        yield db
    finally:
        await db.close()


def row_to_dict(row: aiosqlite.Row | None) -> dict | None:
    return dict(row) if row is not None else None