-- 113 迁移前置兼容修复。
--
-- 113 已经进入生产，文件必须保持字节不变。旧快照库中存在两类历史脏数据，
-- 会让原版 113 在“加新约束/唯一索引”时失败：
--   1. sales_daily_facts 仍有旧约束不接受的渠道值；
--   2. cost_exceptions 同一范围的旧行会生成重复 scope_key。
--
-- 本文件不是迁移，不写 schema_migrations。它只做幂等兼容准备：
--   - 113 已执行时立即跳过；
--   - 清理旧库数据，让随后执行的原版 113 可以通过。
--
-- 由 deploy/ubuntu-deploy.sh 在数据库迁移前自动执行。

DO $preflight$
DECLARE
  v_has_113 BOOLEAN := FALSE;
  v_sales_has_mode BOOLEAN := FALSE;
  v_scope_duplicates BIGINT := 0;
  v_scope_missing BIGINT := 0;
BEGIN
  IF to_regclass('public.schema_migrations') IS NOT NULL THEN
    EXECUTE $query$
      SELECT EXISTS (
        SELECT 1
        FROM public.schema_migrations migration
        WHERE to_jsonb(migration)->>'filename' = '113_finance_channel_cutover.sql'
           OR to_jsonb(migration)->>'name' = '113_finance_channel_cutover'
      )
    $query$ INTO v_has_113;
  END IF;

  IF v_has_113 THEN
    RAISE NOTICE '113 已执行，跳过前置兼容修复';
    RETURN;
  END IF;

  IF to_regclass('public.sales_daily_facts') IS NOT NULL THEN
    SELECT EXISTS (
      SELECT 1
      FROM pg_attribute
      WHERE attrelid = 'public.sales_daily_facts'::regclass
        AND attname = 'fulfillment_mode'
        AND NOT attisdropped
    ) INTO v_sales_has_mode;

    IF v_sales_has_mode THEN
      EXECUTE $sql$
        ALTER TABLE public.sales_daily_facts
          DROP CONSTRAINT IF EXISTS chk_sales_daily_facts_fulfillment_mode
      $sql$;

      EXECUTE $sql$
        UPDATE public.sales_daily_facts
        SET fulfillment_mode = CASE
          WHEN fulfillment_mode = 'legacy_platform' THEN 'archived'
          ELSE 'unclassified'
        END
        WHERE fulfillment_mode NOT IN (
          'work_order', 'affiliate_dash', 'third_party_voucher',
          'manual', 'unclassified', 'archived'
        )
      $sql$;

      -- 迁移前临时使用新旧并集的约束；原版 113 会立即替换成最终约束。
      EXECUTE $sql$
        ALTER TABLE public.sales_daily_facts
          ADD CONSTRAINT chk_sales_daily_facts_fulfillment_mode
          CHECK (
            fulfillment_mode IN (
              'work_order', 'affiliate_dash', 'third_party_voucher',
              'manual', 'unclassified', 'archived'
            )
          )
      $sql$;

      RAISE NOTICE 'sales_daily_facts 历史渠道值已兼容归一';
    END IF;
  END IF;

  IF to_regclass('public.cost_exceptions') IS NOT NULL THEN
    EXECUTE $sql$
      ALTER TABLE public.cost_exceptions
        ADD COLUMN IF NOT EXISTS scope_key TEXT,
        ADD COLUMN IF NOT EXISTS item_count INTEGER NOT NULL DEFAULT 1,
        ADD COLUMN IF NOT EXISTS first_seen_at TIMESTAMPTZ,
        ADD COLUMN IF NOT EXISTS last_seen_at TIMESTAMPTZ
    $sql$;

    EXECUTE $sql$
      WITH duplicate_scope_keys AS (
        SELECT scope_key
        FROM public.cost_exceptions
        WHERE status <> 'resolved'
          AND NULLIF(BTRIM(scope_key), '') IS NOT NULL
        GROUP BY scope_key
        HAVING COUNT(*) > 1
      )
      UPDATE public.cost_exceptions ce
      SET scope_key =
            COALESCE(NULLIF(BTRIM(ce.reason), ''), 'legacy')
            || '|'
            || COALESCE(ce.order_item_id::text, ce.subject_id::text, ce.id::text)
            || '|legacy:'
            || ce.id,
          first_seen_at = COALESCE(ce.first_seen_at, ce.created_at),
          last_seen_at = COALESCE(ce.last_seen_at, ce.created_at)
      WHERE ce.scope_key IS NULL
         OR BTRIM(ce.scope_key) = ''
         OR ce.first_seen_at IS NULL
         OR ce.last_seen_at IS NULL
         OR (
           ce.status <> 'resolved'
           AND ce.scope_key IN (SELECT scope_key FROM duplicate_scope_keys)
         )
    $sql$;

    EXECUTE $sql$
      SELECT COUNT(*)
      FROM (
        SELECT scope_key
        FROM public.cost_exceptions
        WHERE status <> 'resolved'
          AND NULLIF(BTRIM(scope_key), '') IS NOT NULL
        GROUP BY scope_key
        HAVING COUNT(*) > 1
      ) duplicate_scope_keys
    $sql$ INTO v_scope_duplicates;

    EXECUTE $sql$
      SELECT COUNT(*)
      FROM public.cost_exceptions
      WHERE scope_key IS NULL OR BTRIM(scope_key) = ''
    $sql$ INTO v_scope_missing;

    IF v_scope_duplicates > 0 THEN
      RAISE EXCEPTION
        'cost_exceptions 仍有 % 组重复 scope_key，113 无法创建唯一索引',
        v_scope_duplicates;
    END IF;

    IF v_scope_missing > 0 THEN
      RAISE EXCEPTION
        'cost_exceptions 仍有 % 行 scope_key 为空，113 的唯一索引前置数据不完整',
        v_scope_missing;
    END IF;

    RAISE NOTICE 'cost_exceptions 历史 scope_key 已保证唯一';
  END IF;
END
$preflight$;