-- Migration: Add Google OAuth Support
-- Description: Adds googleId field to User table and makes password optional for OAuth users
-- Date: 2025-01-01

-- Step 1: Add googleId column (nullable, unique)
ALTER TABLE "User" ADD COLUMN "googleId" TEXT;

-- Step 2: Make password column nullable (for OAuth users who don't have passwords)
ALTER TABLE "User" ALTER COLUMN "password" DROP NOT NULL;

-- Step 3: Add unique constraint on googleId
ALTER TABLE "User" ADD CONSTRAINT "User_googleId_key" UNIQUE ("googleId");

-- Step 4: Create index on googleId for faster lookups
CREATE INDEX "User_googleId_idx" ON "User"("googleId");

-- Step 5: Verify existing indexes (email should already be indexed)
-- CREATE INDEX "User_email_idx" ON "User"("email"); -- Should already exist

-- Notes:
-- 1. Existing users with passwords will continue to work normally
-- 2. New OAuth users will have NULL password and a googleId
-- 3. Users can have both password and googleId if they link accounts
-- 4. Email remains unique across all users (OAuth and traditional)

-- Rollback instructions (if needed):
-- ALTER TABLE "User" DROP CONSTRAINT "User_googleId_key";
-- DROP INDEX "User_googleId_idx";
-- ALTER TABLE "User" DROP COLUMN "googleId";
-- ALTER TABLE "User" ALTER COLUMN "password" SET NOT NULL;