-- 8. ai：调用流水账（架构 §3.6）
-- 来源：docs/architecture/schema-draft.sql（2026-11-03 验证过的草案）
CREATE TABLE ai_call (                                  -- 不存原文；输入按 input_hash 去对象存储取
  id              uuid PRIMARY KEY,
  tenant_id       uuid NOT NULL,
  job_type        text NOT NULL CHECK (job_type IN ('parse_job', 'check_run')),
  job_id          uuid NOT NULL,                        -- 不加外键：删除项目后成本数据保留
  task            text NOT NULL,                        -- 如 extract.qualification
  capability      text NOT NULL CHECK (capability IN ('vision', 'fast', 'reasoning', 'embedding')),
  provider        text NOT NULL,
  model           text NOT NULL,
  prompt_id       text NOT NULL,
  prompt_version  text NOT NULL,
  prompt_hash     bytea NOT NULL,
  input_hash      bytea NOT NULL,
  output_hash     bytea,
  tokens_in       int,
  tokens_out      int,
  tokens_cached   int,
  latency_ms      int,
  output_mode     text CHECK (output_mode IN ('json_schema', 'json_mode', 'repaired')),
  error_class     text CHECK (error_class IN ('timeout', 'rate_limited', 'server', 'network', 'bad_output')),
  cost_micro_cny  bigint,                               -- 估算成本，百万分之一元
  created_at      timestamptz NOT NULL DEFAULT now()
);
CREATE INDEX ON ai_call (tenant_id, job_id);
CREATE INDEX ON ai_call (created_at);
CREATE TRIGGER ai_call_append_only BEFORE UPDATE OR DELETE ON ai_call
  FOR EACH ROW EXECUTE FUNCTION forbid_change();