<?php

namespace App\Services;

use App\Models\WhatsappConversation;
use App\Models\WhatsappMenu;
use App\Models\WhatsappSystemConfig;
use App\Models\WhatsappUser;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;

class WhatsappBotService
{
    private string $token;
    private string $phoneNumberId;
    private string $apiUrl;

    public function __construct()
    {
        $this->token         = WhatsappSystemConfig::get('whatsapp_token');
        $this->phoneNumberId = WhatsappSystemConfig::get('phone_number_id');
        $this->apiUrl        = WhatsappSystemConfig::get('whatsapp_api_url', 'https://graph.facebook.com/v22.0/');
    }

    // ──────────────────────────────────────────────────────────
    // Punto de entrada principal
    // ──────────────────────────────────────────────────────────

    public function handle(WhatsappUser $user, string $texto, string $tipo = 'text'): void
    {
        // Usuario bloqueado → ignorar
        if ($user->status === 'blocked') {
            return;
        }

        // Atendido por asesor → solo almacenar, no responder
        if ($user->in_service) {
            return;
        }

        // Bot deshabilitado para este usuario → ignorar
        if (! $user->bot_enabled) {
            return;
        }

        // Bot deshabilitado globalmente → ignorar
        if (WhatsappSystemConfig::get('bot_enabled', '1') !== '1') {
            return;
        }

        // Medios (imagen, video, audio, documento, etc.) → aviso y salir
        if (! in_array($tipo, ['text', 'interactive'])) {
            $msg = 'Recibimos tu ' . $tipo . '. Un asesor te contactará pronto.';
            $this->saveOutgoing($user->id, $msg);
            $this->sendText($user->phone_number, $msg);
            return;
        }

        $texto = trim($texto);

        // ── Comandos especiales ──────────────────────────────
        if ($this->isMenuCommand($texto)) {
            $this->enviarMenuPrincipal($user);
            return;
        }

        if ($this->isBackCommand($texto)) {
            $this->irAtras($user);
            return;
        }

        if ($this->isAdvisorCommand($texto)) {
            $this->transferirAsesor($user);
            return;
        }

        // ── Primera visita → bienvenida ──────────────────────
        if (! $user->welcome_sent_at) {
            $this->enviarBienvenida($user);
            return;
        }

        // ── Navegación por menú ──────────────────────────────
        $this->procesarSeleccion($user, $texto);
    }

    // ──────────────────────────────────────────────────────────
    // Comandos
    // ──────────────────────────────────────────────────────────

    private function isMenuCommand(string $texto): bool
    {
        return in_array(mb_strtolower($texto), ['menu', 'menú', 'inicio', 'start', 'hola', 'hi']);
    }

    private function isBackCommand(string $texto): bool
    {
        return in_array(mb_strtolower($texto), ['atras', 'atrás', 'volver', 'back', 'regresar']);
    }

    private function isAdvisorCommand(string $texto): bool
    {
        return in_array(mb_strtolower($texto), ['asesor', 'agente', 'humano', 'ayuda']);
    }

    // ──────────────────────────────────────────────────────────
    // Flujos de respuesta
    // ──────────────────────────────────────────────────────────

    private function enviarBienvenida(WhatsappUser $user): void
    {
        $msg = WhatsappSystemConfig::get(
            'welcome_message',
            '¡Hola! Bienvenido. Escribe *menu* para ver las opciones disponibles.'
        );

        $user->update(['welcome_sent_at' => now(), 'current_menu_id' => null]);
        $this->saveOutgoing($user->id, $msg);
        $this->sendText($user->phone_number, $msg);

        // Mostrar menú principal después del saludo
        $this->enviarMenuPrincipal($user);
    }

    private function enviarMenuPrincipal(WhatsappUser $user): void
    {
        $menu = WhatsappMenu::where('is_main', 1)->where('is_active', 1)->first();

        if (! $menu) {
            $msg = WhatsappSystemConfig::get('default_no_match', 'No hay opciones disponibles en este momento.');
            $this->saveOutgoing($user->id, $msg);
            $this->sendText($user->phone_number, $msg);
            return;
        }

        $user->update(['current_menu_id' => $menu->id]);
        $texto = $this->formatMenu($menu);
        $this->saveOutgoing($user->id, $texto);
        $this->sendText($user->phone_number, $texto);
    }

    private function irAtras(WhatsappUser $user): void
    {
        $menuActual = $user->current_menu_id
            ? WhatsappMenu::find($user->current_menu_id)
            : null;

        $menuPadre = ($menuActual && $menuActual->parent_id)
            ? WhatsappMenu::find($menuActual->parent_id)
            : null;

        if ($menuPadre && $menuPadre->is_active) {
            $user->update(['current_menu_id' => $menuPadre->id]);
            $texto = $this->formatMenu($menuPadre);
            $this->saveOutgoing($user->id, $texto);
            $this->sendText($user->phone_number, $texto);
        } else {
            $this->enviarMenuPrincipal($user);
        }
    }

    private function transferirAsesor(WhatsappUser $user): void
    {
        $msg = WhatsappSystemConfig::get(
            'advisor_message',
            'Un asesor se comunicará contigo en breve. Por favor espera.'
        );

        $user->update([
            'advisor_requested' => true,
            'in_service'        => false,
            'current_menu_id'   => null,
        ]);

        $this->saveOutgoing($user->id, $msg);
        $this->sendText($user->phone_number, $msg);
    }

    private function procesarSeleccion(WhatsappUser $user, string $texto): void
    {
        if (! $user->current_menu_id) {
            $this->enviarMenuPrincipal($user);
            return;
        }

        $menu = WhatsappMenu::find($user->current_menu_id);

        if (! $menu || ! $menu->is_active) {
            $this->enviarMenuPrincipal($user);
            return;
        }

        // Solo aceptar selección numérica
        $numero = is_numeric($texto) ? (int) $texto : null;
        $opcion = $numero
            ? $menu->options()->where('option_number', $numero)->where('is_active', 1)->first()
            : null;

        if (! $opcion) {
            $noMatch  = WhatsappSystemConfig::get('default_no_match', 'Opción no reconocida. Escribe el número de la opción deseada.');
            $fullMsg  = $noMatch . "\n\n" . $this->formatMenu($menu);
            $this->saveOutgoing($user->id, $fullMsg);
            $this->sendText($user->phone_number, $fullMsg);
            return;
        }

        match ($opcion->action_type) {
            'submenu'  => $this->irASubmenu($user, $opcion),
            'message'  => $this->responderMensaje($user, $opcion),
            'advisor'  => $this->transferirAsesor($user),
            'template' => $this->enviarPlantilla($user, $opcion),
            default    => $this->responderMensaje($user, $opcion),
        };
    }

    private function irASubmenu(WhatsappUser $user, object $opcion): void
    {
        $subMenu = WhatsappMenu::find($opcion->action_value);

        if (! $subMenu || ! $subMenu->is_active) {
            $msg = WhatsappSystemConfig::get('default_no_match', 'Opción no disponible en este momento.');
            $this->saveOutgoing($user->id, $msg);
            $this->sendText($user->phone_number, $msg);
            return;
        }

        $user->update(['current_menu_id' => $subMenu->id]);
        $texto = $this->formatMenu($subMenu);
        $this->saveOutgoing($user->id, $texto);
        $this->sendText($user->phone_number, $texto);
    }

    private function responderMensaje(WhatsappUser $user, object $opcion): void
    {
        $texto = (string) ($opcion->action_value ?? '');
        $this->saveOutgoing($user->id, $texto);
        $this->sendText($user->phone_number, $texto);

        // Volver al menú principal tras la respuesta
        $menuPrincipal = WhatsappMenu::where('is_main', 1)->where('is_active', 1)->first();
        if ($menuPrincipal) {
            $user->update(['current_menu_id' => $menuPrincipal->id]);
            $textoMenu = $this->formatMenu($menuPrincipal);
            $this->saveOutgoing($user->id, $textoMenu);
            $this->sendText($user->phone_number, $textoMenu);
        }
    }

    private function enviarPlantilla(WhatsappUser $user, object $opcion): void
    {
        $templateName = (string) ($opcion->action_value ?? '');

        $payload = [
            'messaging_product' => 'whatsapp',
            'to'                => $user->phone_number,
            'type'              => 'template',
            'template'          => [
                'name'     => $templateName,
                'language' => ['code' => 'es'],
            ],
        ];

        $this->saveOutgoing($user->id, "[Plantilla: {$templateName}]");
        $this->callApi('messages', $payload);
    }

    // ──────────────────────────────────────────────────────────
    // Helpers de formato
    // ──────────────────────────────────────────────────────────

    private function formatMenu(WhatsappMenu $menu): string
    {
        $lines = [$menu->message];

        foreach ($menu->options()->where('is_active', 1)->get() as $op) {
            $lines[] = "{$op->option_number}. {$op->title}";
        }

        return implode("\n", $lines);
    }

    // ──────────────────────────────────────────────────────────
    // Envío a la API de WhatsApp Cloud
    // ──────────────────────────────────────────────────────────

    public function sendText(string $to, string $body): bool
    {
        return $this->callApi('messages', [
            'messaging_product' => 'whatsapp',
            'to'                => $to,
            'type'              => 'text',
            'text'              => ['body' => $body, 'preview_url' => false],
        ]);
    }

    public function markRead(string $messageId): void
    {
        $this->callApi('messages', [
            'messaging_product' => 'whatsapp',
            'status'            => 'read',
            'message_id'        => $messageId,
        ]);
    }

    private function callApi(string $endpoint, array $payload): bool
    {
        if (! $this->token || ! $this->phoneNumberId) {
            Log::warning('[WhatsApp] Token o phone_number_id no configurados.');
            return false;
        }

        try {
            $response = Http::withToken($this->token)
                ->timeout(10)
                ->post("{$this->apiUrl}{$this->phoneNumberId}/{$endpoint}", $payload);

            if (! $response->successful()) {
                Log::error('[WhatsApp] API error: ' . $response->body());
            }

            return $response->successful();
        } catch (\Throwable $e) {
            Log::error('[WhatsApp] Excepción al llamar API: ' . $e->getMessage());
            return false;
        }
    }

    private function saveOutgoing(int $userId, string $content): void
    {
        WhatsappConversation::create([
            'user_id'      => $userId,
            'direction'    => 'outgoing',
            'message_type' => 'text',
            'content'      => $content,
            'status'       => 'sent',
        ]);
    }
}