using Elternbeirat.Contracts;
using Elternbeirat.PocketBase;
using Elternbeirat.Web.Components;
using Elternbeirat.Web.Features.Events;
using Microsoft.AspNetCore.HttpOverrides;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddRazorComponents();

// The typed client reads content from PocketBase over its REST API. The base URL
// comes from config: appsettings for local dev, the PocketBase__BaseUrl env var
// on the server (see compose.yaml).
var pocketBaseUrl = builder.Configuration["PocketBase:BaseUrl"]
                    ?? throw new InvalidOperationException("PocketBase:BaseUrl is not configured.");
builder.Services.AddHttpClient<PocketBaseClient>(client =>
{
    client.BaseAddress = new Uri(pocketBaseUrl);
    // Every page waits for PocketBase. The default wait is 100 seconds, so if
    // PocketBase is down the page would hang that long. 5 seconds fails fast instead.
    client.Timeout = TimeSpan.FromSeconds(5);
});

var app = builder.Build();

// NPM sits in front of the app and handles HTTPS. Without this line the app would
// think every request is plain HTTP and would see NPM's IP, not the visitor's.
// KnownNetworks/KnownProxies are left empty on purpose: only NPM reaches the app.
app.UseForwardedHeaders(
    new ForwardedHeadersOptions
    {
        ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
    });

if (app.Environment.IsDevelopment() is false)
{
    app.UseExceptionHandler("/Error", createScopeForErrors: true);
    // No UseHsts() and no UseHttpsRedirection() here: NPM already handles HTTPS.
    // Adding them behind NPM would send the browser into a redirect loop.
}

// Don't add UseStatusCodePagesWithReExecute here. Blazor already shows its own
// not-found page. That middleware would catch *every* error code, so when PocketBase
// is down (a 503) it would wrongly show "not found" instead of our own message.
app.UseAntiforgery();

app.MapStaticAssets();
app.MapRazorComponents<App>();

// Calendar feed people can subscribe to. It returns calendar data, not a web page,
// so it is a plain endpoint, not a Razor page. If PocketBase is down it returns an
// empty calendar rather than an error.
app.MapGet("/events.ics", async (PocketBaseClient pocketBase, CancellationToken token) =>
{
    IReadOnlyList<Event> events;
    try
    {
        events = await pocketBase.GetEventsAsync(token);
    }
    catch (PocketBaseUnavailableException)
    {
        events = [];
    }

    return Results.Text(IcsCalendar.Build(events), "text/calendar; charset=utf-8");
});

// Status page for an outside monitor (Uptime Kuma) to check. One check tells all
// three states apart: no reply = the app is down, 503 = the app runs but PocketBase
// is down, 200 = both are fine. It talks to PocketBase directly, not through the
// page-rendering code, so it can still report when that code is the thing failing.
app.MapGet("/health", async (PocketBaseClient pocketBase, CancellationToken token) =>
    await pocketBase.IsHealthyAsync(token)
        ? Results.Text("healthy", "text/plain; charset=utf-8")
        : Results.Text(
            "PocketBase unreachable",
            "text/plain; charset=utf-8",
            statusCode: StatusCodes.Status503ServiceUnavailable));

app.Run();