using Microsoft.Playwright;

namespace PageFetcherApi.Services;

/// <summary>
/// Singleton hosted service that owns the Playwright Chromium browser process for the lifetime of the application.
/// Launches the browser once at startup and exposes it for injection into <see cref="PageFetcherService"/>.
/// </summary>
public sealed class PlaywrightBrowserService : IHostedService, IAsyncDisposable
{
    private IPlaywright? _playwright;
    private IBrowser? _browser;
    private readonly ILogger<PlaywrightBrowserService> _logger;

    public PlaywrightBrowserService(ILogger<PlaywrightBrowserService> logger)
    {
        _logger = logger;
    }

    /// <summary>The running Chromium browser instance. Available after <see cref="StartAsync"/> completes.</summary>
    public IBrowser Browser => _browser ?? throw new InvalidOperationException("Browser has not been started yet.");

    /// <inheritdoc />
    public async Task StartAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Launching Playwright Chromium browser...");
        _playwright = await Playwright.CreateAsync();
        _browser = await _playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions
        {
            Headless = true,
            Args = ["--no-sandbox", "--disable-setuid-sandbox", "--disable-dev-shm-usage"]
        });
        _logger.LogInformation("Playwright Chromium browser launched successfully.");
    }

    /// <inheritdoc />
    public async Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Closing Playwright Chromium browser...");
        if (_browser is not null) await _browser.CloseAsync();
    }

    /// <inheritdoc />
    public async ValueTask DisposeAsync()
    {
        if (_browser is not null) await _browser.DisposeAsync();
        _playwright?.Dispose();
    }
}