<?php

namespace App\Services\AIPrompt;

use Uri;

/**
 * Use OpenAI API to get answers from a model.
 */
class OpenAPIPrompt implements IAIPrompt
{
    private ?string $host;
    private ?string $token = null;

    public function __construct(?string $host = null) {
        //dd($host ?? config('llm.api.host')); // DEBUG TODO : Is null ? so thows error because $host is normally of type non null string
        $this->host = $host ?? config('llm.api.host');
        if (config('llm.api.token')) {
            $this->token = config('llm.api.token');
        }
    }

    private function getHeaders(): array
    {
        return [
            'Authorization: ' . ($this->token ? 'Bearer ' . $this->token : ''),
            'Content-Type: application/json',
        ];
    }

    /**
     * Call the OpenAI API with the given endpoint and body.
     * @param string $endpoint
     * @param string $body
     * @throws \Exception
     * @return string
     */
    private function callAPI(string $endpoint, string $body): string
    {
        $url = $this->host . $endpoint;

        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $this->getHeaders());
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode !== 200) {
            throw new \Exception("Error calling OpenAI API: HTTP $httpCode - $response");
        }
        return $response;
    }

    /**
     * Call the OpenAI API generate endpoint. to generate a response to a prompt.
     * @param string $model
     * @param string $prompt
     * @param array $images
     * @return void
     */
    public function generate(string $model, string $prompt, array $images = [], string $outputFormat = null, string $systemMessage = null, bool $keepAlive = true, bool $shouldThink = false): string
    {
        /*
            Generate a completion

            POST /api/generate

            Generate a response for a given prompt with a provided model. This is a streaming endpoint, so there will be a series of responses. The final response object will include statistics and additional data from the request.
            Parameters

                model: (required) the model name
                prompt: the prompt to generate a response for
                suffix: the text after the model response
                images: (optional) a list of base64-encoded images (for multimodal models such as llava)
                think: (for thinking models) should the model think before responding?

            Advanced parameters (optional):

                format: the format to return a response in. Format can be json or a JSON schema
                options: additional model parameters listed in the documentation for the Modelfile such as temperature
                system: system message to (overrides what is defined in the Modelfile)
                template: the prompt template to use (overrides what is defined in the Modelfile)
                stream: if false the response will be returned as a single response object, rather than a stream of objects
                raw: if true no formatting will be applied to the prompt. You may choose to use the raw parameter if you are specifying a full templated prompt in your request to the API
                keep_alive: controls how long the model will stay loaded into memory following the request (default: 5m)
                context (deprecated): the context parameter returned from a previous request to /generate, this can be used to keep a short conversational memory

            Structured outputs

            Structured outputs are supported by providing a JSON schema in the format parameter. The model will generate a response that matches the schema. See the structured outputs example below.
            JSON mode

            Enable JSON mode by setting the format parameter to json. This will structure the response as a valid JSON object. See the JSON mode example below.

            Important

            **It's important to instruct the model to use JSON in the prompt. Otherwise, the model may generate large amounts whitespace.**
        */

        // Transform the images to base64
        foreach ($images as &$image) {
            if (file_exists($image)) {
                $image = base64_encode(file_get_contents($image));
            }
        }

        $body = [
            'model' => $model,
            'prompt' => $prompt,
            'images' => $images,
            'think' => $shouldThink,
            'stream' => false,
        ];

        if ($systemMessage !== null) {
            $body['system'] = $systemMessage;
        }
        if ($outputFormat !== null) {
            $body['format'] = json_decode($outputFormat);
        }
        if (!$keepAlive) {
            $body['keep_alive'] = "0m";
        }

        $body = json_encode($body);

        dump($body);
        $response = $this->callAPI('/api/generate', $body);
        $decodedResponse = json_decode($response, true);
        if (json_last_error() !== JSON_ERROR_NONE) {
            throw new \Exception("Error decoding JSON response: " . json_last_error_msg());
        }
        return $decodedResponse['response'] ?? '';
    }
}