SET NAMES utf8mb4;

-- One row per managed test account. model_id 0 falls back to the configured
-- default model so operations can switch every agent at once.
CREATE TABLE IF NOT EXISTS ai_agents (
  user_id BIGINT UNSIGNED NOT NULL,
  model_id BIGINT UNSIGNED NOT NULL DEFAULT 0,
  persona VARCHAR(1000) NOT NULL DEFAULT '',
  enabled TINYINT(1) NOT NULL DEFAULT 1,
  daily_reply_limit INT UNSIGNED NOT NULL DEFAULT 0,
  reply_count INT UNSIGNED NOT NULL DEFAULT 0,
  last_reply_at DATETIME(3) NULL,
  created_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  updated_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
  PRIMARY KEY (user_id),
  KEY idx_ai_agents_enabled (enabled)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

-- A durable queue rather than an in-memory one: replies survive a restart and
-- several instances can share it. Claiming is an UPDATE that stamps claim_token
-- instead of SELECT ... FOR UPDATE SKIP LOCKED, because deployments still run
-- MySQL 5.7 where SKIP LOCKED does not parse.
-- pending_key is NULL once a job leaves the pending state, so the unique index
-- allows exactly one waiting job per conversation and collapses a burst of
-- incoming messages into a single reply.
CREATE TABLE IF NOT EXISTS ai_reply_jobs (
  id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  conversation_id BIGINT UNSIGNED NOT NULL,
  agent_user_id BIGINT UNSIGNED NOT NULL,
  trigger_message_id BIGINT UNSIGNED NOT NULL DEFAULT 0,
  status TINYINT UNSIGNED NOT NULL DEFAULT 0,
  attempts TINYINT UNSIGNED NOT NULL DEFAULT 0,
  run_after DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  claim_token CHAR(32) NOT NULL DEFAULT '',
  last_error VARCHAR(500) NOT NULL DEFAULT '',
  created_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  updated_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
  pending_key BIGINT UNSIGNED GENERATED ALWAYS AS (IF(status = 0, conversation_id, NULL)) STORED,
  PRIMARY KEY (id),
  UNIQUE KEY uk_ai_reply_jobs_pending (pending_key),
  KEY idx_ai_reply_jobs_due (status, run_after),
  KEY idx_ai_reply_jobs_claim (claim_token),
  KEY idx_ai_reply_jobs_agent (agent_user_id, created_at)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;