-- LLM Token 用量统计
CREATE TABLE IF NOT EXISTS llm_usage (
    id BIGSERIAL PRIMARY KEY,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    user_id TEXT NOT NULL DEFAULT '',
    model TEXT NOT NULL DEFAULT '',
    provider TEXT NOT NULL DEFAULT 'deepseek',
    prompt_tokens INTEGER NOT NULL DEFAULT 0,
    completion_tokens INTEGER NOT NULL DEFAULT 0,
    total_tokens INTEGER NOT NULL DEFAULT 0,
    cache_hit_tokens INTEGER NOT NULL DEFAULT 0,
    cache_miss_tokens INTEGER NOT NULL DEFAULT 0
);

CREATE INDEX IF NOT EXISTS idx_llm_usage_created ON llm_usage (created_at DESC);