PRAGMA foreign_keys = ON;

CREATE TABLE IF NOT EXISTS users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    nick TEXT NOT NULL UNIQUE,
    token TEXT NOT NULL UNIQUE,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    last_seen DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS channel_members (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    channel_id INTEGER NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    joined_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(channel_id, user_id)
);

CREATE TABLE IF NOT EXISTS messages (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    channel_id INTEGER REFERENCES channels(id) ON DELETE CASCADE,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    content TEXT NOT NULL,
    is_dm INTEGER NOT NULL DEFAULT 0,
    dm_target_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX IF NOT EXISTS idx_messages_channel ON messages(channel_id, created_at);
CREATE INDEX IF NOT EXISTS idx_messages_dm ON messages(user_id, dm_target_id, created_at);
CREATE INDEX IF NOT EXISTS idx_users_token ON users(token);