-- Fix for suppliers split and foreign keys

-- 1. Move remaining suppliers from customers to suppliers table if type column exists
SET @dbname = DATABASE();
SET @tablename = 'customers';
SET @columnname = 'type';
SET @preparedStatement = (SELECT IF(
  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
   WHERE TABLE_SCHEMA = @dbname AND TABLE_NAME = @tablename AND COLUMN_NAME = @columnname) > 0,
  'INSERT IGNORE INTO suppliers (id, name, email, phone, tax_id, balance, credit_limit, created_at, total_spent) SELECT id, name, email, phone, tax_id, balance, credit_limit, created_at, total_spent FROM customers WHERE type = "supplier"',
  'SELECT 1'
));
PREPARE stmt FROM @preparedStatement;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- 2. Delete them from customers if type column exists
SET @preparedStatement = (SELECT IF(
  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
   WHERE TABLE_SCHEMA = @dbname AND TABLE_NAME = @tablename AND COLUMN_NAME = @columnname) > 0,
  'DELETE FROM customers WHERE type = "supplier"',
  'SELECT 1'
));
PREPARE stmt FROM @preparedStatement;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- 3. Drop type column if it exists
SET @preparedStatement = (SELECT IF(
  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
   WHERE TABLE_SCHEMA = @dbname AND TABLE_NAME = @tablename AND COLUMN_NAME = @columnname) > 0,
  'ALTER TABLE customers DROP COLUMN type',
  'SELECT 1'
));
PREPARE stmt FROM @preparedStatement;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- 4. Fix foreign keys for supplier_id in stock_items
SET @tablename = 'stock_items';
SET @constraintname = 'fk_stock_items_supplier';
SET @preparedStatement = (SELECT IF(
  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
   WHERE CONSTRAINT_SCHEMA = @dbname AND TABLE_NAME = @tablename AND CONSTRAINT_NAME = @constraintname AND CONSTRAINT_TYPE = 'FOREIGN KEY') > 0,
  'ALTER TABLE stock_items DROP FOREIGN KEY fk_stock_items_supplier',
  'SELECT 1'
));
PREPARE stmt FROM @preparedStatement;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

ALTER TABLE stock_items ADD CONSTRAINT fk_stock_items_supplier FOREIGN KEY (supplier_id) REFERENCES suppliers(id) ON DELETE SET NULL;

-- 5. Fix foreign keys for supplier_id in purchase_returns
SET @tablename = 'purchase_returns';
SET @constraintname = 'purchase_returns_ibfk_2';
SET @preparedStatement = (SELECT IF(
  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
   WHERE CONSTRAINT_SCHEMA = @dbname AND TABLE_NAME = @tablename AND CONSTRAINT_NAME = @constraintname AND CONSTRAINT_TYPE = 'FOREIGN KEY') > 0,
  'ALTER TABLE purchase_returns DROP FOREIGN KEY purchase_returns_ibfk_2',
  'SELECT 1'
));
PREPARE stmt FROM @preparedStatement;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

ALTER TABLE purchase_returns ADD CONSTRAINT purchase_returns_ibfk_2 FOREIGN KEY (supplier_id) REFERENCES suppliers(id) ON DELETE SET NULL;