-- Three-layer inventory model: Product -> Pan(盘) -> Bolt(匹)

-- Pan table: each row = one physical pan/roll, belongs to a product
CREATE TABLE IF NOT EXISTS `inv_product_pan` (
    `id`         BIGINT NOT NULL AUTO_INCREMENT,
    `pan_id`     VARCHAR(32) NOT NULL,
    `product_id` VARCHAR(32) NOT NULL,
    `name`       VARCHAR(50) NOT NULL DEFAULT '' COMMENT 'pan label: A, B, C...',
    `position`   VARCHAR(100) NOT NULL DEFAULT '' COMMENT 'physical location: Shanghai, Nanjing...',
    `sort_order` INT NOT NULL DEFAULT 0,
    `tenant_id`  VARCHAR(32) NOT NULL DEFAULT '',
    `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    `updated_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    PRIMARY KEY (`id`),
    UNIQUE KEY `uk_pan_id` (`pan_id`),
    KEY `idx_product_id` (`product_id`),
    KEY `idx_tenant_id` (`tenant_id`),
    KEY `idx_position` (`position`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

-- Bolt table: each row = one physical bolt/piece, belongs to a pan
CREATE TABLE IF NOT EXISTS `inv_product_bolt` (
    `id`         BIGINT NOT NULL AUTO_INCREMENT,
    `bolt_id`    VARCHAR(32) NOT NULL,
    `pan_id`     VARCHAR(32) NOT NULL COMMENT 'FK to inv_product_pan',
    `length_m`   DECIMAL(10,2) NOT NULL DEFAULT 0.00 COMMENT 'length in meters',
    `sort_order` INT NOT NULL DEFAULT 0,
    `tenant_id`  VARCHAR(32) NOT NULL DEFAULT '',
    `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    `updated_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
    PRIMARY KEY (`id`),
    UNIQUE KEY `uk_bolt_id` (`bolt_id`),
    KEY `idx_pan_id` (`pan_id`),
    KEY `idx_tenant_id` (`tenant_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

-- Add composite index for product summary aggregation (panel 1)
-- Use PREPARE/EXECUTE to skip if index already exists (MySQL has no CREATE INDEX IF NOT EXISTS).
SET @ix = (SELECT COUNT(*) FROM information_schema.STATISTICS
    WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'inv_product' AND INDEX_NAME = 'idx_product_name_tenant');
SET @s = IF(@ix = 0,
    'ALTER TABLE `inv_product` ADD KEY `idx_product_name_tenant` (`product_name`, `tenant_id`)',
    'SELECT 1');
PREPARE stmt FROM @s; EXECUTE stmt; DEALLOCATE PREPARE stmt;