-- T0201: Create sessions table for tracking active user sessions
CREATE TABLE IF NOT EXISTS sessions (
    id BIGSERIAL PRIMARY KEY,
    user_id BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    token_hash VARCHAR(255) NOT NULL UNIQUE,
    ip_address VARCHAR(45),
    user_agent TEXT,
    expires_at TIMESTAMP NOT NULL,
    last_activity TIMESTAMP NOT NULL DEFAULT NOW(),
    created_at TIMESTAMP NOT NULL DEFAULT NOW()
);

CREATE INDEX IF NOT EXISTS idx_sessions_user_id ON sessions(user_id);
CREATE INDEX IF NOT EXISTS idx_sessions_token_hash ON sessions(token_hash);
CREATE INDEX IF NOT EXISTS idx_sessions_expires_at ON sessions(expires_at);