<?php
/**
 * Pro fix: suggest structured attributes from product context via OpenRouter.
 *
 * @package AgentReadyForWooCommerce
 */

defined( 'ABSPATH' ) || exit;

/**
 * Class ARWC_Fix_Attributes_AI
 *
 * Pro, AI-backed. When a product has few or no structured attributes, this asks
 * OpenRouter to propose machine-readable name/value attribute pairs derived from
 * the title and description, which are then added as custom product attributes
 * after the merchant approves.
 *
 * Inert without Pro (the fixer only registers AI fixes when Pro is active) and
 * fails closed if the OpenRouter client is missing/unconfigured. The model is
 * instructed not to fabricate values; proposals are shown before any write.
 * Usage is capped by {@see ARWC_OpenRouter}.
 */
class ARWC_Fix_Attributes_AI extends ARWC_Abstract_Fix {

	/**
	 * This fix is Pro-only.
	 *
	 * @var bool
	 */
	protected $is_pro = true;

	/**
	 * Max attributes to add in one run.
	 *
	 * @var int
	 */
	const MAX_ATTRS = 6;

	/**
	 * OpenRouter client (null when not Pro / not wired).
	 *
	 * @var ARWC_OpenRouter|null
	 */
	protected $ai;

	/**
	 * Constructor.
	 *
	 * @param ARWC_OpenRouter|null $ai OpenRouter client.
	 */
	public function __construct( $ai = null ) {
		$this->ai = $ai;
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_id() {
		return 'attributes_ai';
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_label() {
		return __( 'Suggest attributes (AI)', 'agentictrack-agent-readiness-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_description() {
		return __( 'Proposes machine-readable attributes (e.g. material, color, size) from the product title and description. You approve before they are added.', 'agentictrack-agent-readiness-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 *
	 * Does not call the AI; only reports that there is room to add attributes.
	 */
	public function preview( WC_Product $product ) {
		$count = $this->count_attributes( $product );
		if ( $count >= 3 ) {
			return array();
		}

		return array(
			array(
				'field'       => 'attributes',
				'label'       => __( 'Structured attributes', 'agentictrack-agent-readiness-for-woocommerce' ),
				'before'      => sprintf(
					/* translators: %d: current attribute count. */
					_n( '%d attribute', '%d attributes', $count, 'agentictrack-agent-readiness-for-woocommerce' ),
					$count
				),
				'after'       => '',
				'needs_input' => false,
				'auto'        => false,
				'generate'    => true,
				'note'        => __( 'Generate attribute suggestions from the product context to review before they are added.', 'agentictrack-agent-readiness-for-woocommerce' ),
			),
		);
	}

	/**
	 * Generate proposed attributes for review, WITHOUT writing anything.
	 *
	 * @param WC_Product $product Product.
	 * @return array|WP_Error Review payload, or WP_Error.
	 */
	public function generate( WC_Product $product ) {
		$pairs = $this->ask_ai( $product );
		if ( is_wp_error( $pairs ) ) {
			return $pairs;
		}

		// Drop any the merchant already has so the preview reflects what will change.
		$new = array();
		foreach ( $pairs as $name => $value ) {
			if ( ! $this->has_attribute( $product, $name ) ) {
				$new[ $name ] = $value;
			}
		}
		if ( empty( $new ) ) {
			return new WP_Error( 'arwc_ai_nothing_new', __( 'AI did not find any new attributes to add.', 'agentictrack-agent-readiness-for-woocommerce' ) );
		}

		$display = array();
		foreach ( $new as $name => $value ) {
			$display[] = $name . ': ' . $value;
		}

		return array(
			'field'       => 'attributes',
			'label'       => __( 'Structured attributes', 'agentictrack-agent-readiness-for-woocommerce' ),
			'before'      => sprintf(
				/* translators: %d: current attribute count. */
				_n( '%d attribute now', '%d attributes now', $this->count_attributes( $product ), 'agentictrack-agent-readiness-for-woocommerce' ),
				$this->count_attributes( $product )
			),
			'after'       => implode( ' · ', $display ),
			'editable'    => false,
			'apply_field' => 'attributes_json',
			'apply_value' => wp_json_encode( $new ),
			'note'        => __( 'These attributes will be added. Apply to save.', 'agentictrack-agent-readiness-for-woocommerce' ),
		);
	}

	/**
	 * {@inheritDoc}
	 */
	public function apply( WC_Product $product, array $input ) {
		// Preferred path: apply the reviewed attributes the merchant approved.
		if ( isset( $input['attributes_json'] ) && '' !== trim( (string) $input['attributes_json'] ) ) {
			$pairs = $this->parse_pairs( (string) wp_unslash( $input['attributes_json'] ) );
			if ( empty( $pairs ) ) {
				return new WP_Error( 'arwc_ai_empty', __( 'No valid attributes to add.', 'agentictrack-agent-readiness-for-woocommerce' ) );
			}
			return $this->add_pairs( $product, $pairs );
		}

		// Fallback path: generate and add in one step.
		$pairs = $this->ask_ai( $product );
		if ( is_wp_error( $pairs ) ) {
			return $pairs;
		}
		if ( empty( $pairs ) ) {
			return new WP_Error( 'arwc_ai_empty', __( 'AI did not return any usable attributes.', 'agentictrack-agent-readiness-for-woocommerce' ) );
		}
		return $this->add_pairs( $product, $pairs );
	}

	/**
	 * Ask the model for attribute name/value pairs (no writes).
	 *
	 * @param WC_Product $product Product.
	 * @return array<string,string>|WP_Error
	 */
	protected function ask_ai( WC_Product $product ) {
		if ( ! $this->ai instanceof ARWC_OpenRouter ) {
			return new WP_Error( 'arwc_ai_unavailable', __( 'AI fixes are unavailable.', 'agentictrack-agent-readiness-for-woocommerce' ) );
		}

		$desc   = trim( wp_strip_all_tags( (string) $product->get_description() . ' ' . (string) $product->get_short_description() ) );
		$system = 'You extract structured product attributes for an e-commerce catalog. Return ONLY a compact JSON object mapping attribute names to string values, e.g. {"Material":"Cotton","Color":"Navy"}. Use at most ' . self::MAX_ATTRS . ' attributes. Only include attributes you can justify from the given text or title; never invent values. If nothing is justified, return {}.';
		$user   = sprintf( "Title: %s\n\nText:\n%s", $product->get_name(), '' === $desc ? '(none)' : $desc );

		$raw = $this->ai->complete( $system, $user );
		if ( is_wp_error( $raw ) ) {
			return $raw;
		}

		return $this->parse_pairs( $raw );
	}

	/**
	 * Add name/value pairs as custom attributes (skipping any already present).
	 *
	 * @param WC_Product           $product Product.
	 * @param array<string,string> $pairs   Attribute pairs.
	 * @return ARWC_Fix_Result
	 */
	protected function add_pairs( WC_Product $product, array $pairs ) {
		$attributes = $product->get_attributes();
		$result     = $this->result();
		$added      = 0;

		foreach ( $pairs as $name => $value ) {
			if ( $added >= self::MAX_ATTRS ) {
				break;
			}
			if ( $this->has_attribute( $product, $name ) ) {
				continue; // Do not overwrite an attribute the merchant already has.
			}

			$attribute = new WC_Product_Attribute();
			$attribute->set_name( $name );
			$attribute->set_options( array( $value ) );
			$attribute->set_visible( true );
			$attributes[] = $attribute;
			$added++;

			$result->add_change( 'attr_' . sanitize_key( $name ), $name, '', $value );
		}

		if ( $added > 0 ) {
			$product->set_attributes( $attributes );
			$product->save();
		}

		return $result;
	}

	/**
	 * Whether the product already has a (non-taxonomy) attribute by this name.
	 *
	 * @param WC_Product $product Product.
	 * @param string     $name    Attribute name.
	 * @return bool
	 */
	protected function has_attribute( WC_Product $product, $name ) {
		foreach ( $product->get_attributes() as $attribute ) {
			if ( $attribute instanceof WC_Product_Attribute && ! $attribute->is_taxonomy() && strtolower( $attribute->get_name() ) === strtolower( (string) $name ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Count existing attributes that carry values.
	 *
	 * @param WC_Product $product Product.
	 * @return int
	 */
	protected function count_attributes( WC_Product $product ) {
		$count = 0;
		foreach ( $product->get_attributes() as $attribute ) {
			if ( $attribute instanceof WC_Product_Attribute && ! empty( $attribute->get_options() ) ) {
				$count++;
			}
		}
		return $count;
	}

	/**
	 * Parse the model's JSON into a clean name => value map (sanitized).
	 *
	 * @param string $raw Raw model output.
	 * @return array<string,string>
	 */
	protected function parse_pairs( $raw ) {
		// Be lenient: extract the first {...} block if the model added prose.
		if ( preg_match( '/\{.*\}/s', $raw, $m ) ) {
			$raw = $m[0];
		}
		$data = json_decode( $raw, true );
		if ( ! is_array( $data ) ) {
			return array();
		}

		$pairs = array();
		foreach ( $data as $name => $value ) {
			if ( is_array( $value ) ) {
				$value = implode( ', ', array_map( 'strval', $value ) );
			}
			$name  = sanitize_text_field( (string) $name );
			$value = sanitize_text_field( (string) $value );
			if ( '' === $name || '' === $value ) {
				continue;
			}
			$pairs[ $name ] = $value;
		}
		return $pairs;
	}
}