CREATE TYPE "Role" AS ENUM ('ADMIN', 'FINANCE', 'MEMBER');
CREATE TYPE "ApprovalType" AS ENUM ('CHAIR_A', 'CHAIR_B', 'FINANCE');
CREATE TYPE "ApprovalStatus" AS ENUM ('PENDING', 'APPROVED');

CREATE TABLE "working_groups" (
  "id" TEXT NOT NULL,
  "name" TEXT NOT NULL,
  "total_budget" DECIMAL(10,2) NOT NULL,
  "color_code" TEXT NOT NULL,
  "created_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
  "updated_at" TIMESTAMP(3) NOT NULL,
  CONSTRAINT "working_groups_pkey" PRIMARY KEY ("id")
);

CREATE TABLE "users" (
  "id" TEXT NOT NULL,
  "name" TEXT NOT NULL,
  "email" TEXT NOT NULL,
  "password_hash" TEXT NOT NULL,
  "role" "Role" NOT NULL,
  "approval_preference" "ApprovalType",
  "working_group_id" TEXT,
  "created_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
  "updated_at" TIMESTAMP(3) NOT NULL,
  CONSTRAINT "users_pkey" PRIMARY KEY ("id")
);

CREATE TABLE "expenses" (
  "id" TEXT NOT NULL,
  "title" TEXT NOT NULL,
  "amount" DECIMAL(10,2) NOT NULL,
  "creator_id" TEXT NOT NULL,
  "ag_id" TEXT NOT NULL,
  "approval_status" "ApprovalStatus" NOT NULL DEFAULT 'PENDING',
  "paid_at" TIMESTAMP(3),
  "documented_at" TIMESTAMP(3),
  "proof_url" TEXT,
  "notes" TEXT,
  "created_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
  "updated_at" TIMESTAMP(3) NOT NULL,
  CONSTRAINT "expenses_pkey" PRIMARY KEY ("id")
);

CREATE TABLE "approvals" (
  "id" TEXT NOT NULL,
  "expense_id" TEXT NOT NULL,
  "user_id" TEXT NOT NULL,
  "approval_type" "ApprovalType" NOT NULL,
  "timestamp" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
  CONSTRAINT "approvals_pkey" PRIMARY KEY ("id")
);

CREATE UNIQUE INDEX "working_groups_name_key" ON "working_groups"("name");
CREATE UNIQUE INDEX "users_email_key" ON "users"("email");
CREATE UNIQUE INDEX "approvals_expense_id_approval_type_key" ON "approvals"("expense_id", "approval_type");

ALTER TABLE "users"
  ADD CONSTRAINT "users_working_group_id_fkey"
  FOREIGN KEY ("working_group_id") REFERENCES "working_groups"("id")
  ON DELETE SET NULL ON UPDATE CASCADE;

ALTER TABLE "expenses"
  ADD CONSTRAINT "expenses_creator_id_fkey"
  FOREIGN KEY ("creator_id") REFERENCES "users"("id")
  ON DELETE RESTRICT ON UPDATE CASCADE;

ALTER TABLE "expenses"
  ADD CONSTRAINT "expenses_ag_id_fkey"
  FOREIGN KEY ("ag_id") REFERENCES "working_groups"("id")
  ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE "approvals"
  ADD CONSTRAINT "approvals_expense_id_fkey"
  FOREIGN KEY ("expense_id") REFERENCES "expenses"("id")
  ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE "approvals"
  ADD CONSTRAINT "approvals_user_id_fkey"
  FOREIGN KEY ("user_id") REFERENCES "users"("id")
  ON DELETE CASCADE ON UPDATE CASCADE;