<?php
/**
 * Model Registry
 *
 * Centralized source of truth for model defaults, labels,
 * capabilities, and provider support across the plugin.
 *
 * @package WP_Agentic_Writer
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class WPAW_Model_Registry
 *
 * Single source of truth for model configuration.
 *
 * Usage:
 *   $defaults = WPAW_Model_Registry::get_task_defaults();
 *   $registry = WPAW_Model_Registry::get_registry();
 */
class WPAW_Model_Registry {

	/**
	 * Task type constants.
	 */
	const TASK_CHAT = 'chat';
	const TASK_CLARITY = 'clarity';
	const TASK_PLANNING = 'planning';
	const TASK_WRITING = 'writing';
	const TASK_EXECUTION = 'execution';
	const TASK_REFINEMENT = 'refinement';
	const TASK_ANALYSIS = 'analysis';
	const TASK_SUMMARIZE = 'summarize';
	const TASK_IMAGE = 'image';

	/**
	 * Get the complete model registry.
	 *
	 * Structure:
	 *   'task_type' => [
	 *     'default' => 'model_id',
	 *     'fallback' => 'model_id',  // optional
	 *     'label' => 'Human-readable name',
	 *     'description' => 'What this model is used for',
	 *     'supported_providers' => ['openrouter', 'local', 'codex'],  // optional
	 *     'capabilities' => ['chat', 'streaming', 'vision'],  // optional
	 *   ]
	 *
	 * @since 0.2.0
	 * @return array Model registry.
	 */
	public static function get_registry() {
		return array(
			'chat' => array(
				'default' => 'google/gemini-2.5-flash',
				'fallback' => 'google/gemini-2.0-flash-exp',
				'label' => 'Chat Model',
				'description' => 'Discussion, research, and recommendations',
				'capabilities' => array( 'chat', 'streaming', 'reasoning' ),
			),
			'clarity' => array(
				'default' => 'google/gemini-2.5-flash',
				'fallback' => 'google/gemini-2.0-flash-exp',
				'label' => 'Clarity Model',
				'description' => 'Prompt analysis and quiz generation',
				'capabilities' => array( 'chat', 'streaming' ),
			),
			'planning' => array(
				'default' => 'google/gemini-2.5-flash',
				'fallback' => 'google/gemini-2.0-flash-exp',
				'label' => 'Planning Model',
				'description' => 'Article outline and structure generation',
				'capabilities' => array( 'chat', 'streaming' ),
			),
			'writing' => array(
				'default' => 'anthropic/claude-3.5-haiku',
				'fallback' => 'google/gemini-2.5-flash',
				'label' => 'Writing Model',
				'description' => 'Article content generation',
				'capabilities' => array( 'chat', 'streaming', 'long_context' ),
			),
			'execution' => array(
				'default' => 'anthropic/claude-3.5-haiku',
				'fallback' => 'google/gemini-2.5-flash',
				'label' => 'Execution Model',
				'description' => 'Article section writing (alias for writing)',
				'capabilities' => array( 'chat', 'streaming' ),
			),
			'refinement' => array(
				'default' => 'anthropic/claude-3.5-sonnet',
				'fallback' => 'anthropic/claude-3.5-haiku',
				'label' => 'Refinement Model',
				'description' => 'Paragraph edits, rewrites, and improvements',
				'capabilities' => array( 'chat', 'streaming' ),
			),
			'analysis' => array(
				'default' => 'google/gemini-2.5-flash',
				'fallback' => 'anthropic/claude-3.5-haiku',
				'label' => 'Analysis Model',
				'description' => 'Content analysis and improvement suggestions',
				'capabilities' => array( 'chat', 'streaming' ),
			),
			'summarize' => array(
				'default' => 'google/gemini-2.5-flash',
				'fallback' => 'anthropic/claude-3.5-haiku',
				'label' => 'Summarization Model',
				'description' => 'Context summarization and compression',
				'capabilities' => array( 'chat' ),
			),
			'image' => array(
				'default' => 'openai/gpt-4o',
				'fallback' => 'openai/dall-e-3',
				'label' => 'Image Generation Model',
				'description' => 'Image generation for articles',
				'capabilities' => array( 'image_generation' ),
				'supported_providers' => array( 'openrouter' ),
			),
		);
	}

	/**
	 * Get default model for a task type.
	 *
	 * @since 0.2.0
	 * @param string $task Task type (chat, planning, execution, etc).
	 * @return string Default model ID.
	 */
	public static function get_default_model( $task ) {
		$registry = self::get_registry();
		$task_data = $registry[ $task ] ?? $registry['chat'];
		return $task_data['default'];
	}

	/**
	 * Get fallback model for a task type.
	 *
	 * @since 0.2.0
	 * @param string $task Task type.
	 * @return string Fallback model ID.
	 */
	public static function get_fallback_model( $task ) {
		$registry = self::get_registry();
		$task_data = $registry[ $task ] ?? $registry['chat'];
		return $task_data['fallback'] ?? $task_data['default'];
	}

	/**
	 * Get all task defaults as key-value pairs.
	 *
	 * @since 0.2.0
	 * @return array Task => default_model pairs.
	 */
	public static function get_task_defaults() {
		$registry = self::get_registry();
		$defaults = array();

		foreach ( $registry as $task => $data ) {
			$defaults[ $task ] = $data['default'];
		}

		return $defaults;
	}

	/**
	 * Get activation defaults (for plugin activation).
	 *
	 * This returns the format expected by the settings option.
	 *
	 * @since 0.2.0
	 * @return array Settings-compatible defaults.
	 */
	public static function get_activation_defaults() {
		return array(
			'planning_model' => self::get_default_model( 'planning' ),
			'execution_model' => self::get_default_model( 'writing' ),
			'image_model' => self::get_default_model( 'image' ),
		);
	}

	/**
	 * Validate a model ID is in the registry.
	 *
	 * @since 0.2.0
	 * @param string $model Model ID.
	 * @return bool True if valid.
	 */
	public static function is_valid_model( $model ) {
		foreach ( self::get_registry() as $task_data ) {
			if ( $model === $task_data['default'] || $model === $task_data['fallback'] ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Get display name for a model ID.
	 *
	 * Extracts a human-readable name from model IDs like
	 * "google/gemini-2.5-flash" -> "Google Gemini 2.5 Flash"
	 *
	 * @since 0.2.0
	 * @param string $model_id Model ID.
	 * @return string Human-readable display name.
	 */
	public static function get_model_display_name( $model_id ) {
		if ( empty( $model_id ) ) {
			return 'Unknown Model';
		}

		// Handle known model ID patterns
		$display_names = array(
			'google/gemini-2.5-flash' => 'Google Gemini 2.5 Flash',
			'google/gemini-2.0-flash-exp' => 'Google Gemini 2.0 Flash',
			'google/gemini-2.0-flash-exp:free' => 'Google Gemini 2.0 Flash',
			'anthropic/claude-3.5-sonnet' => 'Anthropic Claude 3.5 Sonnet',
			'anthropic/claude-3.5-haiku' => 'Anthropic Claude 3.5 Haiku',
			'openai/gpt-4o' => 'OpenAI GPT-4o',
			'openai/dall-e-3' => 'OpenAI DALL-E 3',
			'black-forest-labs/flux-schnell' => 'Black Forest Flux Schnell',
		);

		if ( isset( $display_names[ $model_id ] ) ) {
			return $display_names[ $model_id ];
		}

		// Generate from model ID: "provider/model-name" -> "Provider Model Name"
		$parts = explode( '/', $model_id );
		if ( count( $parts ) >= 2 ) {
			$provider = ucfirst( str_replace( '-', ' ', $parts[0] ) );
			$name = ucwords( str_replace( '-', ' ', $parts[1] ) );
			return trim( $provider . ' ' . $name );
		}

		return ucwords( str_replace( '-', ' ', $model_id ) );
	}

	/**
	 * Get JavaScript-compatible registry for frontend.
	 *
	 * @since 0.2.0
	 * @return array JS-safe registry data.
	 */
	public static function get_frontend_data() {
		$registry = self::get_registry();
		$result = array();

		foreach ( $registry as $task => $data ) {
			$result[ $task ] = array(
				'default' => $data['default'],
				'fallback' => $data['fallback'] ?? null,
				'label' => $data['label'],
			);
		}

		return $result;
	}
}