using Microsoft.Playwright;

namespace Beam.Puppeteer {
    public class PuppetUnitDownloader<T> : UnitDownloaderBinary<T> {
        public AsyncManipulator PuppetManipulator { get; }

        public PuppetUnitDownloader(HttpClient client, AsyncManipulator puppetManipulator, AsyncTransformer<ByteDocument, T> asyncHtmlTransformer, AsyncDownloadFailurePredicate<ByteDocument>[] asyncDownloadFailurePredicates)
            : base(client, asyncHtmlTransformer, asyncDownloadFailurePredicates) {
            PuppetManipulator = puppetManipulator;
        }

        protected override async Task<(bool, T?)> TryDownloadWithNoRetries(string link, CancellationToken ct) {
            var page = await PuppetContext.Browser.Value.NewPageAsync();
            try {
                await page.GotoAsync(link);
                await PuppetManipulator(page);
                var download = await page.WaitForDownloadAsync();

                using var stream = await download.CreateReadStreamAsync();
                byte[] content = new byte[stream.Length];

                await stream.ReadExactlyAsync(content, ct);

                ByteDocument doc = new ByteDocument(download.SuggestedFilename, content);
                if (FailurePredicates is not null && await IsFailure(doc))
                    return (false, default);

                var transformed = await Transformer(doc);
                return (true, transformed);
            } catch (Exception) {
                return (false, default);
            } finally {
                if (!page.IsClosed)
                    await page.CloseAsync();
            }
        }
    }

}