using System.Runtime.InteropServices;
using Microsoft.Extensions.Configuration;
using PuppeteerSharp;
using PuppeteerSharp.Media;
using Transversal.Interfaces;
using Transversal.Models;

namespace Transversal.Services
{
    public class PuppeteerPdfGeneratorService : IPdfGeneratorService, IAsyncDisposable
    {
        private readonly Browser _browser;

        public PuppeteerPdfGeneratorService(IConfiguration config)
        {
            string? executablePath = RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
                ? "/usr/bin/chromium" // Docker/Linux (NO TOCAR)
                : ResolveWindowsBrowserPath(config); // Windows local

            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            {
                if (string.IsNullOrWhiteSpace(executablePath) || !File.Exists(executablePath))
                    throw new InvalidOperationException(
                        $"No se encontró un navegador. Verifique Puppeteer:ExecutablePath. Path evaluado: '{executablePath}'.");
            }

            _browser = Puppeteer.LaunchAsync(new LaunchOptions
            {
                Headless = true,
                ExecutablePath = executablePath,
                Args = RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
                    ? new[] { "--no-sandbox", "--disable-setuid-sandbox" }
                    : Array.Empty<string>()
            }).GetAwaiter().GetResult();
        }

        private static string? ResolveWindowsBrowserPath(IConfiguration config)
        {
            // 1) appsettings: "Puppeteer:ExecutablePath"
            var configured = config["Puppeteer:ExecutablePath"];
            if (!string.IsNullOrWhiteSpace(configured))
                return configured;

            // 2) fallbacks típicos (Chrome/Edge)
            var candidates = new[]
            {
                @"C:\Program Files\Google\Chrome\Application\chrome.exe",
                @"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe",
                @"C:\Program Files\Microsoft\Edge\Application\msedge.exe",
                @"C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe",
            };

            return candidates.FirstOrDefault(File.Exists);
        }

        public async Task<byte[]> GeneratePdfFromHtmlAsync(string htmlContent, PdfGenerationOptions options = null)
        {
            options ??= new PdfGenerationOptions();

            using var page = await _browser.NewPageAsync();
            await page.SetContentAsync(htmlContent);

            var pdfOptions = new PdfOptions
            {
                Format = options.Format,
                Landscape = options.Landscape,
                PrintBackground = options.PrintBackground,
                Scale = options.Scale,
                MarginOptions = options.Margins ?? new MarginOptions(),
                DisplayHeaderFooter = !string.IsNullOrEmpty(options.HeaderTemplate)
                                       || !string.IsNullOrEmpty(options.FooterTemplate),
                HeaderTemplate = options.HeaderTemplate,
                FooterTemplate = options.FooterTemplate
            };

            return await page.PdfDataAsync(pdfOptions);
        }

        public async ValueTask DisposeAsync()
        {
            if (_browser != null)
                await _browser.CloseAsync();
        }
    }
}