using System.Text;
using BlueLaminate.Scraper.Browser;
using BlueLaminate.Scraper.Proxies;
using Microsoft.Extensions.Logging;
using OpenQA.Selenium;

namespace BlueLaminate.Scraper.CsFloat;

/// <summary>
/// Phase-B discovery tool. Drives a real Edge browser through a residential
/// lease to a CSFloat search page, then records every CSFloat <c>/api/</c> JSON
/// response to disk while a human clicks around (open a listing → "Latest
/// Sales"). We don't yet know CSFloat's exact endpoints or DOM selectors, so a
/// human-in-the-loop is the cheapest way to surface the real traffic: the tool
/// just listens and dumps, the operator drives the UI in the visible window.
/// Once we can see the captured shapes we can automate navigation and design the
/// tables.
/// </summary>
public sealed class CsFloatCaptureService
{
    private readonly IProxyProvider _provider;
    private readonly BrowserDriverFactory _factory;
    private readonly ILogger<CsFloatCaptureService> _logger;

    public CsFloatCaptureService(
        IProxyProvider provider,
        BrowserDriverFactory factory,
        ILogger<CsFloatCaptureService> logger)
    {
        _provider = provider;
        _factory = factory;
        _logger = logger;
    }

    /// <summary>
    /// Opens <paramref name="url"/> through the proxy and captures CSFloat API
    /// responses to <paramref name="outputDir"/> until <paramref name="browseUntilDone"/>
    /// completes (the CLI ties that to the operator pressing Enter). When
    /// <paramref name="diagnose"/> is true, every CSFloat-domain response is
    /// logged (url + status + type) to reveal where a login wall appears.
    /// Returns the number of responses written.
    /// </summary>
    public async Task<int> RunAsync(
        string url,
        string outputDir,
        ProxyRequest request,
        bool loadImages,
        bool diagnose,
        Func<Task> browseUntilDone)
    {
        Directory.CreateDirectory(outputDir);

        var lease = _provider.Acquire(request);
        var driver = await _factory.CreateAsync(lease, blockImages: !loadImages);

        var captured = 0;

        void OnResponse(object? sender, NetworkResponseReceivedEventArgs e)
        {
            var responseUrl = e.ResponseUrl;
            if (string.IsNullOrEmpty(responseUrl)
                || !responseUrl.Contains("csfloat", StringComparison.OrdinalIgnoreCase))
            {
                return;
            }

            // Diagnose mode logs every CSFloat-domain response — including the
            // SPA shell, redirects and any 401/403 — so we can see exactly where
            // a Steam-login wall appears even before any /api/ call fires.
            if (diagnose)
            {
                _logger.LogInformation("[{Status}] {Type} {Url}",
                    e.ResponseStatusCode, e.ResponseResourceType, responseUrl);
            }

            // Only JSON API calls get written to disk; skip the shell, images,
            // fonts, analytics, etc. Matches both api.csfloat.com and csfloat.com/api.
            if (!responseUrl.Contains("/api/", StringComparison.OrdinalIgnoreCase))
                return;

            var body = e.ResponseBody;
            if (string.IsNullOrWhiteSpace(body))
            {
                // Body wasn't buffered (e.g. the known Fetch interception race).
                // Log the endpoint so we still learn it exists even if empty.
                _logger.LogWarning("No body captured for {Url} (status {Status}).",
                    responseUrl, e.ResponseStatusCode);
                return;
            }

            try
            {
                var n = Interlocked.Increment(ref captured);
                var fileName = $"{n:D3}_{Sanitize(responseUrl)}.json";
                File.WriteAllText(Path.Combine(outputDir, fileName), body, Encoding.UTF8);
                _logger.LogInformation(
                    "Captured #{N} [{Status}] {Url} → {File} ({Bytes} bytes).",
                    n, e.ResponseStatusCode, responseUrl, fileName, body.Length);
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Failed to write capture for {Url}.", responseUrl);
            }
        }

        var network = driver.Manage().Network;
        network.NetworkResponseReceived += OnResponse;

        try
        {
            _logger.LogInformation("Navigating to {Url}", url);
            driver.Navigate().GoToUrl(url);
            await browseUntilDone();
        }
        finally
        {
            network.NetworkResponseReceived -= OnResponse;
            driver.Quit();
        }

        return captured;
    }

    // Turn a URL into a filesystem-safe, readable, length-capped file stem so the
    // captures are self-describing (the endpoint is visible in the filename).
    private static string Sanitize(string url)
    {
        var trimmed = url
            .Replace("https://", "", StringComparison.OrdinalIgnoreCase)
            .Replace("http://", "", StringComparison.OrdinalIgnoreCase);

        var sb = new StringBuilder(trimmed.Length);
        foreach (var c in trimmed)
            sb.Append(char.IsLetterOrDigit(c) || c is '-' or '.' ? c : '_');

        var stem = sb.ToString();
        return stem.Length > 120 ? stem[..120] : stem;
    }
}