-- S2 of the loan bank-result reconciliation design (design.md 3.1): a failed
-- receipt on a batch with same-lender, same-amount competitors needs an
-- independently reviewed attribution that names the bank submissions it covers.

-- AlterTable
ALTER TABLE "loan_receipt_attributions"
  ADD COLUMN "kind" VARCHAR(16) NOT NULL DEFAULT 'settlement',
  ADD COLUMN "covered_submission_ids" JSONB NOT NULL DEFAULT '[]';
ALTER TABLE "loan_receipt_attributions" ADD CONSTRAINT "loan_receipt_attributions_kind_check" CHECK ("kind" IN ('settlement', 'failure'));
ALTER TABLE "loan_receipt_attributions" ADD CONSTRAINT "loan_receipt_attributions_covered_check" CHECK (
  jsonb_typeof("covered_submission_ids") = 'array'
  AND ("kind" <> 'failure' OR (jsonb_array_length("covered_submission_ids") > 0 AND jsonb_array_length("verification_ids") = 1)));

ALTER TABLE "loan_receipt_attributions" DROP CONSTRAINT "loan_receipt_attributions_basis_kind_check";
ALTER TABLE "loan_receipt_attributions" ADD CONSTRAINT "loan_receipt_attributions_basis_kind_check" CHECK ("basis_kind" IN
  ('customer_serial', 'bank_memo', 'bank_written_confirmation', 'competitors_resolved', 'bank_instruction_ref'));

-- One open/approved attribution per batch and kind.
DROP INDEX "loan_receipt_attributions_one_active_per_batch";
CREATE UNIQUE INDEX "loan_receipt_attributions_one_active_per_batch_kind"
  ON "loan_receipt_attributions"("payment_batch_id", "kind") WHERE "status" IN ('proposed', 'approved');

-- The proposal (now including kind and covered submissions) stays immutable.
CREATE OR REPLACE FUNCTION guard_loan_receipt_attribution_history() RETURNS trigger LANGUAGE plpgsql AS $$
BEGIN
  IF TG_OP = 'DELETE' THEN RAISE EXCEPTION 'loan receipt attribution history is immutable'; END IF;
  IF OLD."status" IN ('rejected', 'superseded') THEN RAISE EXCEPTION 'closed loan receipt attribution is immutable'; END IF;
  IF OLD."status" = 'approved' AND (NEW."status" <> 'superseded' OR NEW."reviewed_by" IS DISTINCT FROM OLD."reviewed_by"
     OR NEW."reviewed_at" IS DISTINCT FROM OLD."reviewed_at" OR NEW."review_note" IS DISTINCT FROM OLD."review_note") THEN
    RAISE EXCEPTION 'approved loan receipt attribution can only be superseded';
  END IF;
  IF OLD."status" = 'proposed' AND NEW."status" IN ('proposed', 'superseded')
     AND (NEW."reviewed_by" IS NOT NULL OR NEW."reviewed_at" IS NOT NULL OR NEW."review_note" IS NOT NULL) THEN
    RAISE EXCEPTION 'unreviewed loan receipt attribution cannot carry review fields';
  END IF;
  IF NEW."payment_batch_id" <> OLD."payment_batch_id" OR NEW."fingerprint" <> OLD."fingerprint" OR NEW."key_id" <> OLD."key_id"
     OR NEW."verification_ids" <> OLD."verification_ids" OR NEW."manual_proposal_ids" <> OLD."manual_proposal_ids"
     OR NEW."competitor_batch_ids" <> OLD."competitor_batch_ids" OR NEW."basis_kind" <> OLD."basis_kind"
     OR NEW."basis_note" <> OLD."basis_note" OR NEW."exclusion_note" <> OLD."exclusion_note"
     OR NEW."proposed_by" <> OLD."proposed_by" OR NEW."proposed_at" <> OLD."proposed_at"
     OR NEW."kind" <> OLD."kind" OR NEW."covered_submission_ids" <> OLD."covered_submission_ids" THEN
    RAISE EXCEPTION 'loan receipt attribution proposal is immutable';
  END IF;
  RETURN NEW;
END $$;