using System.Net;
using MeterVault.Infrastructure.Import;
using MeterVault.Infrastructure.Persistence;
using MeterVault.Integration.Tests.Costing;
using Microsoft.AspNetCore.Localization;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.AspNetCore.TestHost;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using static MeterVault.Integration.Tests.Costing.CostSandbox;

namespace MeterVault.Integration.Tests.Overview;

/// <summary>
/// The Overview page (brief §7.1) rendered by the real app on the frozen clock of <see cref="CostSandbox.Now"/>
/// (server prerender, which reads the initial load): this month to date of the seeded instance says there is no data
/// and offers the latest month as its own period instead of showing it; the previous year shows the sheet's bill with
/// the energy type cards, the attention item with its tariff link, the change table and the composition, in English and
/// German; a manual-cost-only instance shows its month without a meter. Interactive behaviour (chart, toggles) is covered
/// by the pure tests and the browser check.
/// </summary>
[Collection("Timescale")]
public sealed class OverviewPageTests(TimescaleFixture fx) : IAsyncLifetime
{
    public async Task InitializeAsync()
    {
        await using var db = fx.CreateContext();
        await ClearDataAsync(db);
    }

    public async Task DisposeAsync()
    {
        await using var db = fx.CreateContext();
        await ClearDataAsync(db);
    }

    [Fact]
    public async Task The_seeded_overview_explains_an_empty_month_and_shows_the_previous_year_s_bill()
    {
        await LoadReferenceDataAsync();
        int strom;
        await using (var db = fx.CreateContext())
        {
            strom = await db.EnergyTypes.Where(t => t.Key == "electricity").Select(t => (int)t.Id).FirstAsync();
        }

        using var app = new FrozenApp(fx.ConnectionString);

        // Month to date (the default): no data, the dates that have data, and the latest month as its own period — the
        // panels are not silently switched to May.
        var empty = await app.GetAsync("/");
        Assert.Contains("<h1", empty, StringComparison.Ordinal);
        Assert.Contains("No data for this period", empty, StringComparison.Ordinal);
        Assert.Contains("to May 31, 2026.", empty, StringComparison.Ordinal);
        Assert.Contains("Go to latest data", empty, StringComparison.Ordinal);
        Assert.Contains("href=\"/?from=2026-05-01&to=2026-05-31\"", empty, StringComparison.Ordinal);
        Assert.Contains("Latest month with data: May 2026 (Meter data and manual costs)", empty, StringComparison.Ordinal);
        Assert.DoesNotContain("Total (the bill)", empty, StringComparison.Ordinal);
        Assert.Contains($"href=\"/energy/{strom}?period=mtd\"", empty, StringComparison.Ordinal);

        // The previous year: the sheet's bill (7,907.64 € ± 0.02), per-type cards with their own units, what changed,
        // the composition, and the tank's missing price with its tariff link.
        var year = await app.GetAsync("/?period=prev-year");
        Assert.Matches("7,907\\.6[3-6] €", year);
        Assert.Contains("Total cost", year, StringComparison.Ordinal);
        Assert.Contains("This period: Complete", year, StringComparison.Ordinal);
        Assert.Contains("15,661 kWh", year, StringComparison.Ordinal);
        Assert.Contains("213 m³", year, StringComparison.Ordinal);
        Assert.Contains("2,100 L", year, StringComparison.Ordinal);
        Assert.Contains("Billed by grid import", year, StringComparison.Ordinal);
        Assert.Contains("Not priced (no tariff)", year, StringComparison.Ordinal);
        Assert.Contains("Öltank: Unit price not set up.", year, StringComparison.Ordinal);
        Assert.Contains("/admin/tariffs?scope=type", year, StringComparison.Ordinal);
        Assert.Contains("What changed", year, StringComparison.Ordinal);
        Assert.Contains("Total (the bill)", year, StringComparison.Ordinal);
        Assert.Contains("Cost composition", year, StringComparison.Ordinal);
        Assert.Contains("Jan 1 – Dec 31, 2025 compared with Jan 1 – Dec 31, 2024", year, StringComparison.Ordinal);
        Assert.Contains($"href=\"/energy/{strom}?period=prev-year\"", year, StringComparison.Ordinal);
        Assert.Contains("No meters yet:", year, StringComparison.Ordinal);
        Assert.DoesNotContain("No data for this period", year, StringComparison.Ordinal);

        // The same in German: the reader's words and numbers; names are user data.
        var german = await app.GetAsync("/?period=prev-year", "de");
        Assert.Matches("7\\.907,6[3-6] €", german);
        Assert.Contains("Gesamtkosten", german, StringComparison.Ordinal);
        Assert.Contains("Was sich verändert hat", german, StringComparison.Ordinal);
        Assert.Contains("Summe (die Rechnung)", german, StringComparison.Ordinal);
        Assert.Contains("Öltank: Arbeitspreis nicht hinterlegt.", german, StringComparison.Ordinal);
        Assert.Contains("Heizöl", german, StringComparison.Ordinal);
        Assert.DoesNotContain("Total cost", german, StringComparison.Ordinal);

        // The latest month opened as its own period shows May's figures.
        var may = await app.GetAsync("/?from=2026-05-01&to=2026-05-31");
        Assert.Contains("May 1 – May 31, 2026", may, StringComparison.Ordinal);
        Assert.Contains("Total (the bill)", may, StringComparison.Ordinal);

        // A chart selection in the address is kept: the measure is the selected option.
        var chart = await app.GetAsync($"/?period=prev-year&chart=t{strom}:grid-import:kWh");
        Assert.Contains("Strom · Grid import (kWh)", chart, StringComparison.Ordinal);
    }

    [Fact]
    public async Task A_manual_cost_only_instance_shows_its_month_without_any_meter()
    {
        await using var box = new CostSandbox(fx);
        var category = await box.CategoryAsync($"Manual {Guid.NewGuid():N}", 100);
        await box.ManualCostAsync(D(2026, 5, 10), 60, categoryId: category);
        await box.ManualCostAsync(D(2026, 5, 20), 15);

        using var app = new FrozenApp(fx.ConnectionString);
        var html = await app.GetAsync("/?from=2026-05-01&to=2026-05-31");

        Assert.Contains("75.00 €", html, StringComparison.Ordinal);
        Assert.Contains("60.00 €", html, StringComparison.Ordinal);
        Assert.Contains("15.00 €", html, StringComparison.Ordinal);
        Assert.Contains("Uncategorized", html, StringComparison.Ordinal);
        Assert.Contains("Latest month with data: May 2026 (Manual costs)", html, StringComparison.Ordinal);
        Assert.DoesNotContain("No data for this period", html, StringComparison.Ordinal);
    }

    private async Task LoadReferenceDataAsync()
    {
        await using var db = fx.CreateContext();
        var importer = new ReferenceDataImporter(db, new ImportService(db, Normalization(db)), new CsvImporter());
        await importer.LoadAsync(Path.Combine(AppContext.BaseDirectory, "fixtures"));
    }

    private static async Task ClearDataAsync(MeterVaultDbContext db)
    {
        await db.MeterLinks.ExecuteDeleteAsync();
        await db.Consumption.ExecuteDeleteAsync();
        await db.Readings.ExecuteDeleteAsync();
        await db.MeterEvents.ExecuteDeleteAsync();
        await db.ManualCosts.ExecuteDeleteAsync();
        await db.CostCategoryMembers.ExecuteDeleteAsync();
        await db.Tariffs.ExecuteDeleteAsync();
        await db.Tanks.ExecuteDeleteAsync();
        await db.MeterSources.ExecuteDeleteAsync();
        await db.Meters.ExecuteDeleteAsync();
        await db.ImportBatches.ExecuteDeleteAsync();
    }

    /// <summary>The app on the frozen clock of <see cref="CostSandbox.Now"/>; pages come back HTML-decoded.</summary>
    private sealed class FrozenApp : IDisposable
    {
        private readonly MeterVaultAppFactory _root;
        private readonly WebApplicationFactory<Program> _app;

        public FrozenApp(string connectionString)
        {
            _root = new MeterVaultAppFactory(connectionString);
            _app = _root.WithWebHostBuilder(builder =>
                builder.ConfigureTestServices(services => services.AddSingleton<TimeProvider>(new FixedTimeProvider(Now))));
        }

        public async Task<string> GetAsync(string path, string culture = "en")
        {
            using var client = _app.CreateClient();
            client.DefaultRequestHeaders.Add(
                "Cookie",
                CookieRequestCultureProvider.DefaultCookieName + "="
                + Uri.EscapeDataString(CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(culture))));
            using var response = await client.GetAsync(new Uri(path, UriKind.Relative));
            response.EnsureSuccessStatusCode();
            return WebUtility.HtmlDecode(await response.Content.ReadAsStringAsync());
        }

        public void Dispose()
        {
            _app.Dispose();
            _root.Dispose();
        }
    }
}