<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;

class WeaviateService
{
    protected string $host;
    protected ?string $mistralKey;
    protected ?string $weaviateKey;

    public function __construct()
    {
        $host = config('services.weaviate.host', env('WEAVIATE_HOST', 'http://localhost:8080'));
        $host = trim($host, '"\' ');

        if ($host && !str_starts_with($host, 'http://') && !str_starts_with($host, 'https://')) {
            $host = 'https://' . $host;
        }

        $this->host = rtrim($host, '/');
        $this->mistralKey = config('services.mistral.key', env('MISTRAL_API_KEY', ''));
        $this->weaviateKey = config('services.weaviate.api_key', env('WEAVIATE_API_KEY', ''));
    }

    /**
     * Get headers for Weaviate HTTP requests.
     */
    protected function getHeaders(): array
    {
        $headers = [
            'Content-Type' => 'application/json',
        ];

        if ($this->mistralKey) {
            $headers['X-Mistral-Api-Key'] = $this->mistralKey;
        }

        if ($this->weaviateKey) {
            $headers['Authorization'] = 'Bearer ' . $this->weaviateKey;
            $headers['X-Weaviate-Api-Key'] = $this->weaviateKey;
        }

        return $headers;
    }

    /**
     * Check connection and initialize the schema class if it doesn't exist.
     */
    public function initializeSchema(): bool
    {
        try {
            // Check if class already exists
            $response = Http::withHeaders($this->getHeaders())
                ->get("{$this->host}/v1/schema/DocumentChunk");

            if ($response->successful()) {
                // If it exists, let's verify if the property chatbotId exists
                $data = $response->json();
                $hasChatbotId = false;
                if (isset($data['properties'])) {
                    foreach ($data['properties'] as $prop) {
                        if ($prop['name'] === 'chatbotId') {
                            $hasChatbotId = true;
                            break;
                        }
                    }
                }

                // If schema exists but doesn't have chatbotId property, we add it
                if (!$hasChatbotId) {
                    $newProp = [
                        'name' => 'chatbotId',
                        'dataType' => ['text'],
                        'description' => 'The unique ID of the chatbot/client',
                        'moduleConfig' => [
                            'text2vec-mistral' => [
                                'skip' => true
                            ]
                        ]
                    ];
                    Http::withHeaders($this->getHeaders())
                        ->post("{$this->host}/v1/schema/DocumentChunk/properties", $newProp);
                }

                return true;
            }

            if ($response->status() === 404) {
                // Class doesn't exist, create it
                $schema = [
                    'class' => 'DocumentChunk',
                    'description' => 'A chunk of text from a web page or PDF document',
                    'vectorizer' => 'text2vec-mistral',
                    'moduleConfig' => [
                        'text2vec-mistral' => [
                            'model' => 'mistral-embed',
                            'vectorizeClassName' => false
                        ]
                    ],
                    'properties' => [
                        [
                            'name' => 'chatbotId',
                            'dataType' => ['text'],
                            'description' => 'The unique ID of the chatbot/client',
                            'moduleConfig' => [
                                'text2vec-mistral' => [
                                    'skip' => true
                                ]
                            ]
                        ],
                        [
                            'name' => 'content',
                            'dataType' => ['text'],
                            'description' => 'The actual text content of the chunk',
                            'moduleConfig' => [
                                'text2vec-mistral' => [
                                    'skip' => false,
                                    'vectorizePropertyName' => false
                                ]
                            ]
                        ],
                        [
                            'name' => 'source',
                            'dataType' => ['text'],
                            'description' => 'The URL or file path of the source document',
                            'moduleConfig' => [
                                'text2vec-mistral' => [
                                    'skip' => true
                                ]
                            ]
                        ],
                        [
                            'name' => 'title',
                            'dataType' => ['text'],
                            'description' => 'The title of the source document',
                            'moduleConfig' => [
                                'text2vec-mistral' => [
                                    'skip' => true
                                ]
                            ]
                        ]
                    ]
                ];

                $createResponse = Http::withHeaders($this->getHeaders())
                    ->post("{$this->host}/v1/schema", $schema);

                if ($createResponse->successful()) {
                    Log::info("Weaviate schema DocumentChunk initialized successfully.");
                    return true;
                }

                Log::error("Failed to create Weaviate schema: " . $createResponse->body());
                return false;
            }

            return false;
        } catch (\Exception $e) {
            Log::error("Weaviate schema initialization error: " . $e->getMessage());
            return false;
        }
    }

    /**
     * Index a single chunk or multiple chunks of documents for a specific chatbot.
     */
    public function indexChunks(array $chunks, string $chatbotId): bool
    {
        $this->initializeSchema();

        try {
            $objects = [];
            foreach ($chunks as $chunk) {
                $objects[] = [
                    'class' => 'DocumentChunk',
                    'properties' => [
                        'chatbotId' => $chatbotId,
                        'content' => $chunk['content'],
                        'source' => $chunk['source'],
                        'title' => $chunk['title'] ?? 'Document',
                    ]
                ];
            }

            $response = Http::withHeaders($this->getHeaders())
                ->post("{$this->host}/v1/batch/objects", [
                    'objects' => $objects
                ]);

            if ($response->successful()) {
                return true;
            }

            Log::error("Failed to batch index chunks to Weaviate: " . $response->body());
            return false;
        } catch (\Exception $e) {
            Log::error("Weaviate batch index error: " . $e->getMessage());
            return false;
        }
    }

    /**
     * Delete all indexed documents for a specific chatbot.
     */
    public function clearChatbotData(string $chatbotId): bool
    {
        try {
            $payload = [
                'match' => [
                    'class' => 'DocumentChunk',
                    'where' => [
                        'path' => ['chatbotId'],
                        'operator' => 'Equal',
                        'valueText' => $chatbotId
                    ]
                ]
            ];

            $response = Http::withHeaders($this->getHeaders())
                ->delete("{$this->host}/v1/batch/objects", $payload);

            return $response->successful();
        } catch (\Exception $e) {
            Log::error("Weaviate batch delete error: " . $e->getMessage());
            return false;
        }
    }

    /**
     * Query Weaviate for similar text chunks, scoped to a specific chatbot.
     */
    public function search(string $query, string $chatbotId, int $limit = 5): array
    {
        $this->initializeSchema();
        try {
            $graphqlQuery = [
                'query' => '
                    {
                        Get {
                            DocumentChunk(
                                nearText: {
                                    concepts: ["' . addslashes($query) . '"]
                                }
                                where: {
                                    path: ["chatbotId"]
                                    operator: Equal
                                    valueText: "' . addslashes($chatbotId) . '"
                                }
                                limit: ' . $limit . '
                            ) {
                                content
                                source
                                title
                                _additional {
                                    distance
                                }
                            }
                        }
                    }
                '
            ];

            $response = Http::withHeaders($this->getHeaders())
                ->post("{$this->host}/v1/graphql", $graphqlQuery);

            if ($response->successful()) {
                $data = $response->json();
                $results = $data['data']['Get']['DocumentChunk'] ?? [];
                Log::info("Weaviate search for chatbot {$chatbotId} returned " . count($results) . " chunks.");
                return $results;
            }

            Log::error("Weaviate GraphQL search failed: " . $response->body());
            return [];
        } catch (\Exception $e) {
            Log::error("Weaviate search error: " . $e->getMessage());
            return [];
        }
    }
}