using System.Security.Claims;
using LehrerApp.Core.Models;
using LehrerApp.Sync.Models;
using Microsoft.AspNetCore.Mvc;

namespace LehrerApp.Api;

public static class ReadableSnapshotEndpoints
{
    // ── Readable Snapshot ─────────────────────────────────────────────────────

    public static void MapReadableSnapshotEndpoints(this WebApplication app)
    {
        var snap = app.MapGroup("/api/snapshot/readable")
                      .RequireAuthorization();

        // Desktop → Server: aktuellen Snapshot hochladen
        snap.MapPost("/", (
            [FromBody] ReadableSnapshot snapshot,
            ClaimsPrincipal user,
            ReadableSnapshotStore store) =>
        {
            var userId = user.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            if (userId is null) return Results.Unauthorized();

            snapshot.ExportedAt = DateTime.UtcNow;
            store.Store(userId, snapshot);

            return Results.Ok(new
            {
                exportedAt   = snapshot.ExportedAt,
                studentCount = snapshot.Meta.StudentCount,
                groupCount   = snapshot.Meta.GroupCount,
            });
        });

        // WebApp → Server: Snapshot laden
        snap.MapGet("/", (
            ClaimsPrincipal user,
            ReadableSnapshotStore store) =>
        {
            var userId = user.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            if (userId is null) return Results.Unauthorized();

            var snapshot = store.Load(userId);
            if (snapshot is null)
                return Results.NotFound(
                    "Kein Snapshot vorhanden. " +
                    "Bitte zuerst den Desktop-Client mit dem Server verbinden.");

            return Results.Ok(snapshot);
        });

        // Nur Metadaten – für Freshness-Check der WebApp
        snap.MapGet("/meta", (
            ClaimsPrincipal user,
            ReadableSnapshotStore store) =>
        {
            var userId = user.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            if (userId is null) return Results.Unauthorized();

            var meta = store.LoadMeta(userId);
            if (meta is null) return Results.NotFound();

            return Results.Ok(meta);
        });
    }

    // ── Plain Sync (WebApp → EventStore) ─────────────────────────────────────

    public static void MapPlainSyncEndpoints(this WebApplication app)
    {
        var sync = app.MapGroup("/api/sync/plain")
                      .RequireAuthorization();

        // WebApp schreibt Events (Klartext) – werden beim Desktop-Pull abgeholt
        sync.MapPost("/push", (
            [FromBody] List<PlainSyncEvent> events,
            ClaimsPrincipal user,
            PlainEventStore store) =>
        {
            var userId = user.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            if (userId is null) return Results.Unauthorized();

            // Nur erlaubte EntityTypes für WebApp-Schreibzugriff
            var allowed = new HashSet<string>
            {
                "Grade", "ExamResult", "WorkTask", "Lesson"
            };

            var rejected = events
                .Where(e => !allowed.Contains(e.EntityType))
                .Select(e => e.EventId)
                .ToList();

            var permitted = events
                .Where(e => allowed.Contains(e.EntityType))
                .ToList();

            PlainPushResponse result;
            if (permitted.Count > 0)
                result = store.Push(userId, permitted);
            else
                result = new PlainPushResponse { Success = true };

            // Abgelehnte Events mit Grund zurückmelden
            result = result with
            {
                RejectedEventIds = [.. result.RejectedEventIds, .. rejected],
            };

            return Results.Ok(result);
        });
    }
}