<?php
/**
 * Price updater with tax-aware logic and minimum margin safeguards.
 *
 * @package InformatiqSmartPricing
 */

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Price updater class.
 */
class Informatiq_SP_Price_Updater {
	/**
	 * Logger instance.
	 *
	 * @var Informatiq_SP_Logger
	 */
	private $logger;

	/**
	 * Minimum offset from competitor price.
	 *
	 * @var float
	 */
	private $min_offset = 0.05;

	/**
	 * Maximum offset from competitor price.
	 *
	 * @var float
	 */
	private $max_offset = 0.20;

	/**
	 * Constructor.
	 *
	 * @param Informatiq_SP_Logger $logger Logger instance.
	 */
	public function __construct( $logger ) {
		$this->logger = $logger;
	}

	/**
	 * Process all in-stock products.
	 *
	 * @return array Results summary.
	 */
	public function process_all_products() {
		$results = array(
			'processed' => 0,
			'updated'   => 0,
			'skipped'   => 0,
			'errors'    => 0,
		);

		// Get plugin settings.
		$merchant_id   = get_option( 'informatiq_sp_merchant_id' );
		$client_id     = get_option( 'informatiq_sp_client_id' );
		$client_secret = get_option( 'informatiq_sp_client_secret' );
		$refresh_token = get_option( 'informatiq_sp_refresh_token' );
		$minimum_margin = (float) get_option( 'informatiq_sp_minimum_margin', 10 );

		// Validate settings.
		if ( empty( $merchant_id ) || empty( $refresh_token ) ) {
			$this->logger->error( 'Google Merchant settings not configured. Please configure and authorize first.' );
			return $results;
		}

		// Initialize Google API.
		try {
			$google_api = new Informatiq_SP_Google_API( $merchant_id, $client_id, $client_secret, $refresh_token, $this->logger );
		} catch ( Exception $e ) {
			$this->logger->error( 'Failed to initialize Google API: ' . $e->getMessage() );
			return $results;
		}

		// Get all in-stock products.
		$products = $this->get_instock_products();

		$this->logger->info( sprintf( 'Starting price update for %d in-stock products', count( $products ) ) );

		foreach ( $products as $product ) {
			$results['processed']++;

			try {
				$updated = $this->process_single_product( $product, $google_api, $minimum_margin );

				if ( $updated ) {
					$results['updated']++;
				} else {
					$results['skipped']++;
				}
			} catch ( Exception $e ) {
				$results['errors']++;
				$this->logger->error(
					sprintf(
						'Error processing product #%d: %s',
						$product->get_id(),
						$e->getMessage()
					)
				);
			}
		}

		$this->logger->info(
			sprintf(
				'Price update completed. Processed: %d, Updated: %d, Skipped: %d, Errors: %d',
				$results['processed'],
				$results['updated'],
				$results['skipped'],
				$results['errors']
			)
		);

		return $results;
	}

	/**
	 * Get all in-stock products.
	 *
	 * @return array Array of WC_Product objects.
	 */
	private function get_instock_products() {
		$args = array(
			'status'         => 'publish',
			'stock_status'   => 'instock',
			'limit'          => -1,
			'return'         => 'objects',
			'type'           => array( 'simple', 'variable' ),
		);

		return wc_get_products( $args );
	}

	/**
	 * Process a single product.
	 *
	 * @param WC_Product               $product        Product object.
	 * @param Informatiq_SP_Google_API $google_api     Google API instance.
	 * @param float                    $minimum_margin Minimum margin percentage.
	 * @return bool True if price was updated.
	 */
	private function process_single_product( $product, $google_api, $minimum_margin ) {
		// Get product identifiers.
		$sku  = $product->get_sku();
		$gtin = get_post_meta( $product->get_id(), '_gtin', true );

		if ( empty( $sku ) ) {
			$this->logger->warning( sprintf( 'Product #%d has no SKU, skipping', $product->get_id() ) );
			return false;
		}

		// Get competitor price from Google.
		$competitor_price = $google_api->get_competitive_price( $sku, $gtin );

		if ( is_null( $competitor_price ) || $competitor_price <= 0 ) {
			$this->logger->info( sprintf( 'No competitor price found for product #%d (SKU: %s)', $product->get_id(), $sku ) );
			return false;
		}

		// Calculate new price.
		$new_price = $this->calculate_new_price( $product, $competitor_price, $minimum_margin );

		if ( is_null( $new_price ) ) {
			return false;
		}

		// Update product price.
		return $this->update_product_price( $product, $new_price, $competitor_price );
	}

	/**
	 * Calculate new price based on competitor price and minimum margin.
	 *
	 * @param WC_Product $product          Product object.
	 * @param float      $competitor_price Competitor price (tax-inclusive).
	 * @param float      $minimum_margin   Minimum margin percentage.
	 * @return float|null New price or null if cannot be calculated.
	 */
	private function calculate_new_price( $product, $competitor_price, $minimum_margin ) {
		// Generate random offset.
		$random_offset = $this->get_random_offset();

		// Calculate target price (tax-inclusive).
		$target_price_with_tax = $competitor_price - $random_offset;

		// Get minimum allowed price based on cost and margin.
		$minimum_price = $this->get_minimum_price( $product, $minimum_margin );

		// Determine if we need to handle taxes.
		$prices_include_tax = wc_prices_include_tax();

		if ( $prices_include_tax ) {
			// Store prices include tax, so we can set the sale price directly.
			$new_price = $target_price_with_tax;

			// Check against minimum price.
			if ( $new_price < $minimum_price ) {
				$this->logger->warning(
					sprintf(
						'Product #%d: Calculated price %s is below minimum margin %s, using minimum price',
						$product->get_id(),
						wc_price( $new_price ),
						wc_price( $minimum_price )
					)
				);
				$new_price = $minimum_price;
			}
		} else {
			// Store prices exclude tax, need to reverse-calculate base price.
			$new_price = $this->calculate_price_excluding_tax( $product, $target_price_with_tax );

			// Check against minimum price (also excluding tax).
			$minimum_price_excl_tax = $this->calculate_price_excluding_tax( $product, $minimum_price );

			if ( $new_price < $minimum_price_excl_tax ) {
				$this->logger->warning(
					sprintf(
						'Product #%d: Calculated price %s is below minimum margin %s, using minimum price',
						$product->get_id(),
						wc_price( $new_price ),
						wc_price( $minimum_price_excl_tax )
					)
				);
				$new_price = $minimum_price_excl_tax;
			}
		}

		return $new_price;
	}

	/**
	 * Calculate price excluding tax from tax-inclusive price.
	 *
	 * @param WC_Product $product             Product object.
	 * @param float      $price_with_tax      Price including tax.
	 * @return float Price excluding tax.
	 */
	private function calculate_price_excluding_tax( $product, $price_with_tax ) {
		// Get tax rates for the product.
		$tax_rates = WC_Tax::get_rates( $product->get_tax_class() );

		if ( empty( $tax_rates ) ) {
			// No tax, return as-is.
			return $price_with_tax;
		}

		// Calculate total tax rate.
		$tax_rate = 0;
		foreach ( $tax_rates as $rate ) {
			$tax_rate += (float) $rate['rate'];
		}

		// Calculate price excluding tax.
		$price_excl_tax = $price_with_tax / ( 1 + ( $tax_rate / 100 ) );

		return round( $price_excl_tax, wc_get_price_decimals() );
	}

	/**
	 * Get minimum allowed price based on cost and margin.
	 *
	 * @param WC_Product $product        Product object.
	 * @param float      $minimum_margin Minimum margin percentage.
	 * @return float Minimum price.
	 */
	private function get_minimum_price( $product, $minimum_margin ) {
		// Get product cost from WooCommerce Cost of Goods.
		$cost = get_post_meta( $product->get_id(), '_wc_cog_cost', true );

		// Fallback to regular price if cost is not set.
		if ( empty( $cost ) || $cost <= 0 ) {
			$cost = $product->get_regular_price();

			$this->logger->info(
				sprintf(
					'Product #%d has no cost set, using regular price %s as cost',
					$product->get_id(),
					wc_price( $cost )
				)
			);
		}

		// Calculate minimum price with margin.
		$minimum_price = $cost * ( 1 + ( $minimum_margin / 100 ) );

		return $minimum_price;
	}

	/**
	 * Get random offset between min and max.
	 *
	 * @return float Random offset.
	 */
	private function get_random_offset() {
		return $this->min_offset + ( mt_rand() / mt_getrandmax() ) * ( $this->max_offset - $this->min_offset );
	}

	/**
	 * Update product price.
	 *
	 * @param WC_Product $product          Product object.
	 * @param float      $new_price        New sale price.
	 * @param float      $competitor_price Competitor price.
	 * @return bool True if updated successfully.
	 */
	private function update_product_price( $product, $new_price, $competitor_price ) {
		$old_price = $product->get_sale_price();

		// Only update if price has changed.
		if ( (float) $old_price === (float) $new_price ) {
			$this->logger->info(
				sprintf(
					'Product #%d price unchanged at %s',
					$product->get_id(),
					wc_price( $new_price )
				)
			);
			return false;
		}

		// Set sale price.
		$product->set_sale_price( $new_price );
		$product->save();

		// Log price update.
		$this->logger->log_price_update(
			$product->get_id(),
			$product->get_name(),
			$old_price ? $old_price : $product->get_regular_price(),
			$new_price,
			$competitor_price,
			'Price updated via automated sync'
		);

		return true;
	}

	/**
	 * Process single product by ID (for manual sync).
	 *
	 * @param int $product_id Product ID.
	 * @return array Result with success/error message.
	 */
	public function process_product_by_id( $product_id ) {
		$product = wc_get_product( $product_id );

		if ( ! $product ) {
			return array(
				'success' => false,
				'message' => 'Product not found',
			);
		}

		if ( $product->get_stock_status() !== 'instock' ) {
			return array(
				'success' => false,
				'message' => 'Product is not in stock',
			);
		}

		// Get settings.
		$merchant_id    = get_option( 'informatiq_sp_merchant_id' );
		$client_id      = get_option( 'informatiq_sp_client_id' );
		$client_secret  = get_option( 'informatiq_sp_client_secret' );
		$refresh_token  = get_option( 'informatiq_sp_refresh_token' );
		$minimum_margin = (float) get_option( 'informatiq_sp_minimum_margin', 10 );

		if ( empty( $merchant_id ) || empty( $refresh_token ) ) {
			return array(
				'success' => false,
				'message' => 'Google Merchant settings not configured or not authorized',
			);
		}

		try {
			$google_api = new Informatiq_SP_Google_API( $merchant_id, $client_id, $client_secret, $refresh_token, $this->logger );
			$updated    = $this->process_single_product( $product, $google_api, $minimum_margin );

			return array(
				'success' => true,
				'updated' => $updated,
				'message' => $updated ? 'Price updated successfully' : 'No update needed',
			);
		} catch ( Exception $e ) {
			return array(
				'success' => false,
				'message' => 'Error: ' . $e->getMessage(),
			);
		}
	}
}