<?php
if (! defined('ABSPATH')) {
    exit;
}

class ACOSMAIA_AI_API_Client
{
    private $provider;
    private $api_key;
    private $model;
    private $temperature;
    private $max_tokens;
    private $timeout;

    public function __construct($provider = 'openrouter', $api_key = '', $model = '', $temperature = 0.7, $max_tokens = 600, $timeout = 25)
    {
        $this->provider     = sanitize_text_field((string) $provider);
        $this->api_key      = sanitize_text_field((string) $api_key);
        $this->model        = sanitize_text_field((string) $model);
        $this->temperature  = (float) $temperature;
        $this->max_tokens   = (int) $max_tokens;
        $this->timeout      = (int) $timeout;
    }

    public static function from_settings()
    {
        $provider = get_option('acosmaia_api_provider', 'openrouter');

        if ('openai' === $provider) {
            $api_key = get_option('acosmaia_openai_key', '');
            $model   = get_option('acosmaia_openai_model', 'gpt-3.5-turbo');
        } elseif ('gemini' === $provider) {
            $api_key = get_option('acosmaia_gemini_key', '');
            $model   = get_option('acosmaia_gemini_model', 'gemini-2.0-flash');
        } else {
            $api_key = get_option('acosmaia_openrouter_key', '');
            $model   = get_option('acosmaia_model', 'mistralai/mistral-7b-instruct:free');
        }

        $temperature = (float) get_option('acosmaia_temperature', 0.7);
        $max_tokens  = (int) get_option('acosmaia_max_tokens', 600);
        $timeout     = (int) get_option('acosmaia_timeout', 25);

        return new self($provider, $api_key, $model, $temperature, $max_tokens, $timeout);
    }

    public function is_configured()
    {
        return ! empty($this->api_key);
    }

    public function request($system_prompt, $message)
    {
        if (! $this->is_configured()) {
            return new WP_Error('api_not_configured', 'AI API key is not configured.');
        }

        switch ($this->provider) {
            case 'openai':
                return $this->request_openai($system_prompt, $message);
            case 'gemini':
                return $this->request_gemini($system_prompt, $message);
            default:
                return $this->request_openrouter($system_prompt, $message);
        }
    }

    private function request_openrouter($system_prompt, $message)
    {
        // Try the configured model first
        $response = $this->attempt_openrouter_model($system_prompt, $message, $this->model);

        if (is_wp_error($response)) {
            $error = $response->get_error_message();

            // If 404 (model not found), try fallback models
            if (strpos($error, 'No endpoints found') !== false || strpos($error, 'does not exist') !== false) {
                $fallback_models = $this->get_openrouter_fallback_models($this->model);

                foreach ($fallback_models as $model) {
                    $fallback_response = $this->attempt_openrouter_model($system_prompt, $message, $model);

                    if (! is_wp_error($fallback_response)) {
                        // Check if it has valid content
                        $status = (int) wp_remote_retrieve_response_code($fallback_response);
                        $body   = json_decode((string) wp_remote_retrieve_body($fallback_response), true);

                        if ($status >= 200 && $status <= 299 && ! empty($body['choices'][0]['message']['content'])) {
                            return $fallback_response;
                        }
                    }
                }
            }

            return $response;
        }

        return $response;
    }

    private function get_openrouter_fallback_models($exclude_model = '')
    {
        $models = ['openrouter/auto'];

        $dynamic_models = $this->get_openrouter_live_models();
        foreach ($dynamic_models as $model_id) {
            if (! in_array($model_id, $models, true)) {
                $models[] = $model_id;
            }
        }

        if (empty($dynamic_models)) {
            $defaults = [
                'openrouter/auto',
                'openai/gpt-4o-mini',
                'meta-llama/llama-3.1-8b-instruct',
                'google/gemma-2-9b-it',
            ];
            foreach ($defaults as $default_model) {
                if (! in_array($default_model, $models, true)) {
                    $models[] = $default_model;
                }
            }
        }

        $exclude_model = trim((string) $exclude_model);
        if ('' !== $exclude_model) {
            $models = array_values(array_filter($models, function ($model_id) use ($exclude_model) {
                return $model_id !== $exclude_model;
            }));
        }

        return $models;
    }

    private function get_openrouter_live_models()
    {
        $cache_key = 'acosmaia_openrouter_live_models';
        $cached    = get_transient($cache_key);

        if (is_array($cached) && ! empty($cached)) {
            return $cached;
        }

        $response = wp_remote_get('https://openrouter.ai/api/v1/models', [
            'headers' => [
                'Authorization' => 'Bearer ' . $this->api_key,
                'Content-Type'  => 'application/json',
                'HTTP-Referer'  => home_url('/'),
                'X-Title'       => get_bloginfo('name'),
            ],
            'timeout' => 15,
        ]);

        if (is_wp_error($response)) {
            return [];
        }

        $status = (int) wp_remote_retrieve_response_code($response);
        $body   = json_decode((string) wp_remote_retrieve_body($response), true);

        if ($status < 200 || $status > 299 || empty($body['data']) || ! is_array($body['data'])) {
            return [];
        }

        $free_models = [];
        $paid_models = [];

        foreach ($body['data'] as $model) {
            if (! is_array($model) || empty($model['id'])) {
                continue;
            }

            $model_id = sanitize_text_field((string) $model['id']);
            $pricing  = isset($model['pricing']) && is_array($model['pricing']) ? $model['pricing'] : [];

            $prompt_price = isset($pricing['prompt']) ? (float) $pricing['prompt'] : 999.0;
            $completion_price = isset($pricing['completion']) ? (float) $pricing['completion'] : 999.0;

            if ($prompt_price <= 0.0 && $completion_price <= 0.0) {
                $free_models[] = $model_id;
            } else {
                $paid_models[] = $model_id;
            }
        }

        $sorted_models = array_values(array_unique(array_merge($free_models, array_slice($paid_models, 0, 8))));

        if (! empty($sorted_models)) {
            set_transient($cache_key, $sorted_models, 10 * MINUTE_IN_SECONDS);
        }

        return $sorted_models;
    }

    private function attempt_openrouter_model($system_prompt, $message, $model)
    {
        $response = wp_remote_post('https://openrouter.ai/api/v1/chat/completions', [
            'headers' => [
                'Authorization' => 'Bearer ' . $this->api_key,
                'Content-Type'  => 'application/json',
                'HTTP-Referer'  => home_url('/'),
                'X-Title'       => get_bloginfo('name'),
            ],
            'timeout' => max(5, min(120, $this->timeout)),
            'body'    => wp_json_encode([
                'model'       => $model,
                'temperature' => max(0, min(2, $this->temperature)),
                'max_tokens'  => max(100, min(4000, $this->max_tokens)),
                'messages'    => [
                    ['role' => 'system', 'content' => $system_prompt],
                    ['role' => 'user', 'content' => $message],
                ],
            ]),
        ]);

        if (is_wp_error($response)) {
            return $response;
        }

        $status = (int) wp_remote_retrieve_response_code($response);
        $body   = json_decode((string) wp_remote_retrieve_body($response), true);

        if ($status < 200 || $status > 299) {
            $error_msg = isset($body['error']['message']) ? sanitize_text_field((string) $body['error']['message']) : 'Unknown error';
            return new WP_Error('openrouter_error', $error_msg);
        }

        if (empty($body['choices'][0]['message']['content'])) {
            return new WP_Error('openrouter_error', 'No response content from OpenRouter.');
        }

        return $response;
    }

    private function request_openai($system_prompt, $message)
    {
        $response = wp_remote_post('https://api.openai.com/v1/chat/completions', [
            'headers' => [
                'Authorization' => 'Bearer ' . $this->api_key,
                'Content-Type'  => 'application/json',
            ],
            'timeout' => max(5, min(120, $this->timeout)),
            'body'    => wp_json_encode([
                'model'       => $this->model,
                'temperature' => max(0, min(2, $this->temperature)),
                'max_tokens'  => max(100, min(4000, $this->max_tokens)),
                'messages'    => [
                    ['role' => 'system', 'content' => $system_prompt],
                    ['role' => 'user', 'content' => $message],
                ],
            ]),
        ]);

        if (is_wp_error($response)) {
            return $response;
        }

        $status = (int) wp_remote_retrieve_response_code($response);
        $body   = json_decode((string) wp_remote_retrieve_body($response), true);

        if ($status < 200 || $status > 299) {
            $error_msg = isset($body['error']['message']) ? sanitize_text_field((string) $body['error']['message']) : 'Unknown error';
            return new WP_Error('openai_error', $error_msg);
        }

        if (empty($body['choices'][0]['message']['content'])) {
            return new WP_Error('openai_error', 'No response content from OpenAI.');
        }

        return $response;
    }

    private function request_gemini($system_prompt, $message)
    {
        $combined_message = $system_prompt . "\n\nUser: " . $message;
        $response = $this->attempt_gemini_model($this->model, $combined_message);

        if (is_wp_error($response)) {
            $error = $response->get_error_message();

            if (strpos($error, 'not found') !== false || strpos($error, 'not supported for generateContent') !== false) {
                $fallback_models = $this->get_gemini_fallback_models($this->model);
                foreach ($fallback_models as $model) {
                    $fallback_response = $this->attempt_gemini_model($model, $combined_message);
                    if (! is_wp_error($fallback_response)) {
                        return $fallback_response;
                    }
                }
            }

            return $response;
        }

        return $response;
    }

    private function attempt_gemini_model($model, $combined_message)
    {

        $model = preg_replace('#^models/#', '', (string) $model);
        $endpoint = 'https://generativelanguage.googleapis.com/v1beta/models/' . rawurlencode($model) . ':generateContent?key=' . rawurlencode($this->api_key);

        $response = wp_remote_post($endpoint, [
            'headers' => [
                'Content-Type' => 'application/json',
            ],
            'timeout' => max(5, min(120, $this->timeout)),
            'body'    => wp_json_encode([
                'contents' => [
                    [
                        'parts' => [
                            ['text' => $combined_message],
                        ],
                    ],
                ],
                'generationConfig' => [
                    'temperature'     => max(0, min(2, $this->temperature)),
                    'maxOutputTokens' => max(100, min(4000, $this->max_tokens)),
                ],
            ]),
        ]);

        if (is_wp_error($response)) {
            return $response;
        }

        $status = (int) wp_remote_retrieve_response_code($response);
        $body   = json_decode((string) wp_remote_retrieve_body($response), true);

        if ($status < 200 || $status > 299) {
            $error_msg = isset($body['error']['message']) ? sanitize_text_field((string) $body['error']['message']) : 'Unknown error';
            return new WP_Error('gemini_error', $error_msg);
        }

        if (empty($body['candidates'][0]['content']['parts'][0]['text'])) {
            return new WP_Error('gemini_error', 'No response content from Gemini.');
        }

        return $response;
    }

    private function get_gemini_fallback_models($exclude_model = '')
    {
        $models = [];

        $live_models = $this->get_gemini_live_models();
        foreach ($live_models as $model_id) {
            if (! in_array($model_id, $models, true)) {
                $models[] = $model_id;
            }
        }

        if (empty($models)) {
            $models = [
                'gemini-2.0-flash',
                'gemini-2.0-flash-lite',
                'gemini-1.5-flash',
                'gemini-1.5-pro',
            ];
        }

        $exclude_model = preg_replace('#^models/#', '', trim((string) $exclude_model));
        if ('' !== $exclude_model) {
            $models = array_values(array_filter($models, function ($model_id) use ($exclude_model) {
                return $model_id !== $exclude_model;
            }));
        }

        return $models;
    }

    private function get_gemini_live_models()
    {
        $cache_key = 'acosmaia_gemini_live_models';
        $cached    = get_transient($cache_key);

        if (is_array($cached) && ! empty($cached)) {
            return $cached;
        }

        $endpoint = 'https://generativelanguage.googleapis.com/v1beta/models?key=' . rawurlencode($this->api_key);
        $response = wp_remote_get($endpoint, [
            'timeout' => 15,
        ]);

        if (is_wp_error($response)) {
            return [];
        }

        $status = (int) wp_remote_retrieve_response_code($response);
        $body   = json_decode((string) wp_remote_retrieve_body($response), true);
        if ($status < 200 || $status > 299 || empty($body['models']) || ! is_array($body['models'])) {
            return [];
        }

        $models = [];
        foreach ($body['models'] as $model_data) {
            if (! is_array($model_data) || empty($model_data['name'])) {
                continue;
            }

            $methods = isset($model_data['supportedGenerationMethods']) && is_array($model_data['supportedGenerationMethods'])
                ? $model_data['supportedGenerationMethods']
                : [];

            if (! in_array('generateContent', $methods, true)) {
                continue;
            }

            $name = sanitize_text_field((string) $model_data['name']);
            $name = preg_replace('#^models/#', '', $name);

            if ('' !== $name && ! in_array($name, $models, true)) {
                $models[] = $name;
            }
        }

        if (! empty($models)) {
            set_transient($cache_key, $models, 10 * MINUTE_IN_SECONDS);
        }

        return $models;
    }

    public function parse_response($response)
    {
        if (is_wp_error($response)) {
            return ['error' => $response->get_error_message()];
        }

        $status = (int) wp_remote_retrieve_response_code($response);
        $body   = json_decode((string) wp_remote_retrieve_body($response), true);

        if ('openai' === $this->provider) {
            if ($status >= 200 && $status <= 299 && ! empty($body['choices'][0]['message']['content'])) {
                return [
                    'content' => wp_kses_post((string) $body['choices'][0]['message']['content']),
                    'usage'   => isset($body['usage']) && is_array($body['usage']) ? $body['usage'] : [],
                ];
            }

            return ['error' => isset($body['error']['message']) ? sanitize_text_field((string) $body['error']['message']) : 'Unknown error'];
        }

        if ('gemini' === $this->provider) {
            if ($status >= 200 && $status <= 299 && ! empty($body['candidates'][0]['content']['parts'][0]['text'])) {
                $usage = isset($body['usageMetadata']) && is_array($body['usageMetadata']) ? $body['usageMetadata'] : [];
                $prompt_tokens = isset($usage['promptTokenCount']) ? (int) $usage['promptTokenCount'] : 0;
                $completion_tokens = isset($usage['candidatesTokenCount']) ? (int) $usage['candidatesTokenCount'] : 0;
                $total_tokens = isset($usage['totalTokenCount']) ? (int) $usage['totalTokenCount'] : ($prompt_tokens + $completion_tokens);

                return [
                    'content' => wp_kses_post((string) $body['candidates'][0]['content']['parts'][0]['text']),
                    'usage'   => [
                        'prompt_tokens'     => $prompt_tokens,
                        'completion_tokens' => $completion_tokens,
                        'total_tokens'      => $total_tokens,
                    ],
                ];
            }

            return ['error' => isset($body['error']['message']) ? sanitize_text_field((string) $body['error']['message']) : 'Unknown error'];
        }

        if ($status >= 200 && $status <= 299 && ! empty($body['choices'][0]['message']['content'])) {
            return [
                'content' => wp_kses_post((string) $body['choices'][0]['message']['content']),
                'usage'   => isset($body['usage']) && is_array($body['usage']) ? $body['usage'] : [],
            ];
        }

        return ['error' => isset($body['error']['message']) ? sanitize_text_field((string) $body['error']['message']) : 'Unknown error'];
    }
}