using System.Diagnostics;
using System.Globalization;
using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text;
using System.Text.Json;
using Elternbeirat.PocketBase;

namespace Elternbeirat.Web.Tests;

/// <summary>
/// Starts a throwaway PocketBase container once per test run, creates the four
/// content collections and seeds them with a small, known data set. The tests run
/// against this instance instead of the live one, so they are hermetic (no network
/// to Unraid), reproducible (fixed data) and safe (isolated from production).
/// <para>
/// The container is started from the real <c>compose.yaml</c> + <c>compose.dev.yaml</c>
/// (only the <c>eb-pocketbase</c> service, not the web app) by shelling out to
/// <c>docker compose</c>, so the image version, superuser env and port stay defined
/// in one place -- the compose files -- and the tests always exercise the same
/// PocketBase the stack runs.
/// </para>
/// <para>
/// The collection <b>schema</b> is not typed out here: it is imported from
/// <c>pb/pb_migrations/collections_schema.json</c>, the same file the dev seed
/// migration uses, so the schema is defined once and cannot drift between the two.
/// The seeded <b>records</b>, by contrast, are fixed in this file on purpose (not
/// the dev seed's data), so tests assert against values this file controls -- e.g.
/// a non-public draft page that must never appear, and an event at a known time.
/// Requires Docker with the Compose plugin.
/// </para>
/// </summary>
public sealed class PocketBaseFixture : IAsyncLifetime
{
    // The service name and container port as defined in the compose files. Everything
    // else about the container (image version, superuser env, host port) comes from
    // compose, so there is nothing to keep in sync with it here.
    private const string ServiceName = "eb-pocketbase";
    private const int PocketBasePort = 8090;

    // The superuser the dev overlay creates (PB_ADMIN_EMAIL/PASSWORD in
    // compose.dev.yaml); used only to authenticate for the one-time seed.
    private const string AdminEmail = "test@example.com";
    private const string AdminPassword = "test-password"; // >= 8 chars (PB rule)

    // A fixed compose project name for the tests, sibling to the dev stack
    // ("eb-stack"). Fixed (not per-run) so the
    // container names are predictable and a leftover from an aborted run can be
    // cleaned up before the next start. Because it is its own project, it never
    // touches the dev stack -- the container_name is cleared in the test overlay so
    // both projects can coexist.
    private const string Project = "eb-test-stack";

    // One HttpClient shared by all tests through the client; the fixture owns it and
    // disposes it in DisposeAsync. Its BaseAddress is set once the container is up.
    private readonly HttpClient _http = new();

    /// <summary>Creates a <see cref="PocketBaseClient"/> pointed at this container.</summary>
    public PocketBaseClient CreateClient() => new(_http);

    /// <summary>
    /// The base URL the container's PocketBase is reachable at. Set once the
    /// container is up; used to point the web app's client at this instance in the
    /// route smoke tests.
    /// </summary>
    public Uri BaseUrl => _http.BaseAddress
        ?? throw new InvalidOperationException("PocketBase is not started yet.");

    public async Task InitializeAsync()
    {
        // Clear any leftover from an earlier run that was aborted before DisposeAsync
        // (a hard kill), so the fixed-name project starts from a clean, empty volume.
        await ComposeAsync("down", "--volumes", "--remove-orphans");
        // `up --wait` blocks until the service is healthy (the compose healthcheck),
        // so once this returns PocketBase is ready to answer.
        await ComposeAsync("up", "--detach", "--wait", ServiceName);
        _http.BaseAddress = await ResolveBaseUrlAsync();
        await SeedAsync();
    }

    public async Task DisposeAsync()
    {
        _http.Dispose();
        // Remove containers, network and the (dev) volume for this project.
        await ComposeAsync("down", "--volumes");
    }

    /// <summary>Reads the host address compose bound the service port to.</summary>
    private static async Task<Uri> ResolveBaseUrlAsync()
    {
        // `docker compose port <service> <port>` prints e.g. "0.0.0.0:49153".
        var mapping = (await ComposeAsync(
            "port", ServiceName, PocketBasePort.ToString(CultureInfo.InvariantCulture))).Trim();
        var host = mapping[..mapping.LastIndexOf(':')];
        var port = mapping[(mapping.LastIndexOf(':') + 1)..];
        // 0.0.0.0 is a bind address, not something to connect to; use loopback.
        if (host is "0.0.0.0" or "::")
            host = "localhost";
        return new Uri($"http://{host}:{port}");
    }

    /// <summary>
    /// Runs `docker compose -p &lt;project&gt; -f compose.yaml -f compose.dev.yaml &lt;args&gt;`
    /// from the repo root and returns its stdout, throwing on a non-zero exit.
    /// </summary>
    private static async Task<string> ComposeAsync(params string[] args)
    {
        var start = new ProcessStartInfo("docker")
        {
            WorkingDirectory = RepoRoot(),
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
        };
        // compose -p <project> -f <base> -f <dev> -f <test> <args...>. The test
        // overlay swaps the dev overlay's fixed host port for a random one, so the
        // test stack does not fight a running dev stack over port 8090.
        start.ArgumentList.Add("compose");
        start.ArgumentList.Add("-p");
        start.ArgumentList.Add(Project);
        start.ArgumentList.Add("-f");
        start.ArgumentList.Add("compose.yaml");
        start.ArgumentList.Add("-f");
        start.ArgumentList.Add("compose.dev.yaml");
        start.ArgumentList.Add("-f");
        start.ArgumentList.Add("compose.test.yaml");
        foreach (var arg in args)
            start.ArgumentList.Add(arg);

        using var process = Process.Start(start)
            ?? throw new InvalidOperationException("Could not start the docker process.");
        var stdout = await process.StandardOutput.ReadToEndAsync();
        var stderr = await process.StandardError.ReadToEndAsync();
        await process.WaitForExitAsync();

        if (process.ExitCode != 0)
            throw new InvalidOperationException(
                $"`docker compose {string.Join(' ', args)}` failed ({process.ExitCode}): {stderr}");

        return stdout;
    }

    /// <summary>Repo root, resolved by walking up from the test assembly to compose.yaml.</summary>
    private static string RepoRoot()
    {
        // The test binary sits under <repo>/Elternbeirat.Web.Tests/bin/<config>/<tfm>;
        // walk up until the directory that holds the compose files (the repo root).
        var dir = new DirectoryInfo(AppContext.BaseDirectory);
        while (dir is not null && !File.Exists(Path.Combine(dir.FullName, "compose.yaml")))
            dir = dir.Parent;

        return dir?.FullName
            ?? throw new InvalidOperationException("Could not locate the repo root (compose.yaml).");
    }

    /// <summary>
    /// Authenticates as superuser, then imports the shared collection schema and
    /// seeds the fixed test records the tests assert against.
    /// </summary>
    private async Task SeedAsync()
    {
        var token = await AuthenticateAsync(_http);
        _http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(token);

        await ImportCollectionsAsync(_http);
        await SeedRecordsAsync(_http);

        // Drop the superuser token so the tests read as an anonymous visitor would,
        // exercising the public list/view rules rather than a privileged bypass.
        _http.DefaultRequestHeaders.Authorization = null;
    }

    private static async Task<string> AuthenticateAsync(HttpClient http)
    {
        // The superuser upsert runs before serve, so once /api/health answers the
        // account exists; a couple of retries still guard against a race.
        for (var attempt = 0; ; attempt++)
        {
            var response = await http.PostAsJsonAsync(
                "/api/collections/_superusers/auth-with-password",
                new { identity = AdminEmail, password = AdminPassword });

            if (response.IsSuccessStatusCode)
            {
                var payload = await response.Content.ReadFromJsonAsync<AuthResponse>();
                return payload?.Token ?? throw new InvalidOperationException("No auth token returned.");
            }

            if (attempt >= 5)
                response.EnsureSuccessStatusCode(); // give up: throw with the status.

            await Task.Delay(500);
        }
    }

    /// <summary>
    /// Imports the four content collections from the shared schema file, the same
    /// one the dev seed migration reads (<c>pb/pb_migrations/collections_schema.json</c>).
    /// Uses PocketBase's <c>/api/collections/import</c> so the whole schema is
    /// defined in one place instead of being typed out here.
    /// </summary>
    private static async Task ImportCollectionsAsync(HttpClient http)
    {
        // The file maps name -> collection object; the import endpoint wants a
        // flat list, so unwrap the values. deleteMissing=false leaves anything
        // already present untouched (the import is idempotent).
        var path = Path.Combine(RepoRoot(), "pb", "pb_migrations", "collections_schema.json");
        using var schema = JsonDocument.Parse(await File.ReadAllTextAsync(path));
        var collections = schema.RootElement.EnumerateObject()
            .Select(property => property.Value)
            .ToArray();

        // Serialize the JsonElement list back to JSON for the request body.
        var body = JsonSerializer.Serialize(new { collections, deleteMissing = false });
        using var content = new StringContent(body, Encoding.UTF8, "application/json");
        var response = await http.PutAsync(new Uri("/api/collections/import", UriKind.Relative), content);
        response.EnsureSuccessStatusCode();
    }

    private static async Task SeedRecordsAsync(HttpClient http)
    {
        // Pages that the route smoke tests reach through the navigation, the
        // footer or the FAQ hub. Header pages carry a location+order; the FAQ
        // sub-pages are plain content pages without a menu slot. All public.
        await CreateRecordAsync(http, "pages", new
        {
            title = "Startseite", body = "# Willkommen", location = "header",
            order = 1, slug = "home", embed = new[] { "posts", "events" }, @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            title = "Vorstandsteam", body = "# Vorstand", location = "header",
            order = 2, slug = "board", embed = Array.Empty<string>(), @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            // Carries an embed so the ContentPage embed path is covered: /patrons
            // renders its body plus the FAQ teaser.
            title = "Förderverein", body = "# Förderverein", location = "header",
            order = 3, slug = "patrons", embed = new[] { "faqs" }, @public = true,
        });
        // Nav placeholder for the FAQ list (route /faqs is served by FaqList,
        // which shadows this page). Slug matches production's "faqs" nav entry.
        await CreateRecordAsync(http, "pages", new
        {
            title = "FAQ", body = "# Häufige Fragen", location = "header",
            order = 4, slug = "faqs", embed = Array.Empty<string>(), @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            title = "Downloads", body = "# Downloads", location = "header",
            order = 5, slug = "downloads", embed = Array.Empty<string>(), @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            title = "FAQ Mensa", body = "# Mensa", location = "",
            order = 0, slug = "faq-lunch", embed = Array.Empty<string>(), @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            title = "Kontakt", body = "Mail an uns", location = "footer",
            order = 1, slug = "contact", embed = Array.Empty<string>(), @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            title = "Impressum", body = "# Impressum", location = "footer",
            order = 2, slug = "imprint", embed = Array.Empty<string>(), @public = true,
        });
        await CreateRecordAsync(http, "pages", new
        {
            title = "Datenschutz", body = "# Datenschutz", location = "footer",
            order = 3, slug = "privacy", embed = Array.Empty<string>(), @public = true,
        });
        // A draft page that must never appear (public=false).
        await CreateRecordAsync(http, "pages", new
        {
            title = "Entwurf", body = "geheim", location = "header",
            order = 9, slug = "draft", embed = Array.Empty<string>(), @public = false,
        });

        // Posts: newest first once sorted by -date.
        await CreateRecordAsync(http, "posts", new
        {
            date = "2026-03-01 00:00:00.000Z", title = "Neuer Vorstand",
            body = "Text", slug = "new-board", @public = true,
        });
        await CreateRecordAsync(http, "posts", new
        {
            date = "2026-01-15 00:00:00.000Z", title = "Neue Sporthalle",
            body = "Text", slug = "new-hall", @public = true,
        });

        // Events: the meeting carries the wall-clock time the timezone test checks.
        await CreateRecordAsync(http, "events", new
        {
            start = "2026-10-08 19:30:00.000Z", title = "Elternbeiratssitzung",
            location = "Aula", note = "", @public = true,
        });
        await CreateRecordAsync(http, "events", new
        {
            start = "2026-11-22 09:00:00.000Z", end = "2026-11-22 13:00:00.000Z",
            title = "Herbstbasar", location = "Schulhof", note = "", @public = true,
        });

        // Faqs: two topics.
        await CreateRecordAsync(http, "faqs", new
        {
            question = "Wann gibt es Mittagessen?", answer = "Um 12 Uhr.",
            topic = "mensa", @public = true,
        });
        await CreateRecordAsync(http, "faqs", new
        {
            question = "Wie viel kostet ein Schließfach?", answer = "20 Euro.",
            topic = "schliessfach", @public = true,
        });
    }

    private static async Task CreateRecordAsync(HttpClient http, string collection, object record)
    {
        var response = await http.PostAsJsonAsync($"/api/collections/{collection}/records", record);
        response.EnsureSuccessStatusCode();
    }

    private sealed record AuthResponse
    {
        [System.Text.Json.Serialization.JsonPropertyName("token")]
        public string Token { get; init; } = "";
    }
}