using System.Linq;
using System.Text.Json;
using Gott.Extensions;
using Gott.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;

namespace Gott.Endpoints;

public static class AdminEndpoint
{
    public static void MapAdminEndpoints(this WebApplication app)
    {
        app.MapGet("/api/admin/users", HandleListUsers);
        app.MapPost("/api/admin/users", HandleCreateUser);
        app.MapPut("/api/admin/users/{userId}", HandleUpdateUser);
        app.MapPut("/api/admin/users/{userId}/password", HandleResetPassword);
        app.MapDelete("/api/admin/users/{userId}", HandleDeleteUser);
        app.MapPost("/api/admin/users/{userId}/impersonate", HandleImpersonate);
        app.MapPost("/api/admin/users/{userId}/login-link", HandleLoginLink);
    }

    private static async System.Threading.Tasks.Task HandleListUsers(HttpContext ctx, DatabaseService db)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        var users = await db.GetUsers();
        var result = users.Select(u => new
        {
            userId = u.UserId,
            username = u.Username,
            displayName = u.DisplayName,
            isAdmin = u.IsAdmin,
            defaultPath = u.DefaultPath,
            canCreateAgents = u.CanCreateAgents,
            canUseCli = u.CanUseCli,
            createdAt = u.CreatedAt,
            updatedAt = u.UpdatedAt
        });

        await ctx.Response.WriteAsJsonAsync(result);
    }

    private static async System.Threading.Tasks.Task HandleCreateUser(HttpContext ctx, DatabaseService db, AuthService auth)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
        var username = body.TryGetProperty("username", out var u) ? u.GetString() : null;
        var password = body.TryGetProperty("password", out var p) ? p.GetString() : null;
        var displayName = body.TryGetProperty("displayName", out var dn) ? dn.GetString() : null;
        var isAdmin = body.TryGetProperty("isAdmin", out var ia) && ia.GetBoolean();
        var defaultPath = body.TryGetProperty("defaultPath", out var dp) ? dp.GetString() : null;
        var canCreateAgents = !body.TryGetProperty("canCreateAgents", out var cca) || cca.GetBoolean();
        var canUseCli = !body.TryGetProperty("canUseCli", out var cuc) || cuc.GetBoolean();

        if (string.IsNullOrWhiteSpace(username) || string.IsNullOrWhiteSpace(password))
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzername und Passwort erforderlich" });
            return;
        }

        if (password.Length < 4)
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Passwort muss mindestens 4 Zeichen lang sein" });
            return;
        }

        var existing = await db.GetUserByUsername(username);
        if (existing != null)
        {
            ctx.Response.StatusCode = 409;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzername bereits vergeben" });
            return;
        }

        var hash = auth.HashPassword(password);
        var user = await db.CreateUser(username, hash, displayName, isAdmin, defaultPath, canCreateAgents, canUseCli);

        ctx.Response.StatusCode = 201;
        await ctx.Response.WriteAsJsonAsync(new
        {
            userId = user.UserId,
            username = user.Username,
            displayName = user.DisplayName,
            isAdmin = user.IsAdmin,
            defaultPath = user.DefaultPath,
            canCreateAgents = user.CanCreateAgents,
            canUseCli = user.CanUseCli,
            createdAt = user.CreatedAt
        });
    }

    private static async System.Threading.Tasks.Task HandleUpdateUser(HttpContext ctx, DatabaseService db, string userId)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        var user = await db.GetUser(userId);
        if (user == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzer nicht gefunden" });
            return;
        }

        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
        var username = body.TryGetProperty("username", out var u) ? u.GetString() : user.Username;
        var displayName = body.TryGetProperty("displayName", out var dn) ? dn.GetString() : user.DisplayName;
        var isAdmin = body.TryGetProperty("isAdmin", out var ia) ? ia.GetBoolean() : user.IsAdmin;
        var defaultPath = body.TryGetProperty("defaultPath", out var dp) ? dp.GetString() : user.DefaultPath;
        var canCreateAgents = body.TryGetProperty("canCreateAgents", out var cca) ? cca.GetBoolean() : user.CanCreateAgents;
        var canUseCli = body.TryGetProperty("canUseCli", out var cuc) ? cuc.GetBoolean() : user.CanUseCli;

        if (string.IsNullOrWhiteSpace(username))
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzername darf nicht leer sein" });
            return;
        }

        // Prüfen ob anderer User den Username bereits hat
        var existing = await db.GetUserByUsername(username);
        if (existing != null && existing.UserId != userId)
        {
            ctx.Response.StatusCode = 409;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzername bereits vergeben" });
            return;
        }

        await db.UpdateUserAdmin(userId, username, displayName, isAdmin, defaultPath, canCreateAgents, canUseCli);
        var updated = await db.GetUser(userId);

        await ctx.Response.WriteAsJsonAsync(new
        {
            userId = updated.UserId,
            username = updated.Username,
            displayName = updated.DisplayName,
            isAdmin = updated.IsAdmin,
            defaultPath = updated.DefaultPath,
            canCreateAgents = updated.CanCreateAgents,
            canUseCli = updated.CanUseCli,
            createdAt = updated.CreatedAt,
            updatedAt = updated.UpdatedAt
        });
    }

    private static async System.Threading.Tasks.Task HandleResetPassword(HttpContext ctx, DatabaseService db, AuthService auth, string userId)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        var user = await db.GetUser(userId);
        if (user == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzer nicht gefunden" });
            return;
        }

        var body = await JsonSerializer.DeserializeAsync<JsonElement>(ctx.Request.Body);
        var newPassword = body.TryGetProperty("password", out var p) ? p.GetString() : null;

        if (string.IsNullOrWhiteSpace(newPassword) || newPassword.Length < 4)
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Passwort muss mindestens 4 Zeichen lang sein" });
            return;
        }

        var hash = auth.HashPassword(newPassword);
        await db.UpdateUserPassword(userId, hash);

        await ctx.Response.WriteAsJsonAsync(new { ok = true });
    }

    private static async System.Threading.Tasks.Task HandleDeleteUser(HttpContext ctx, DatabaseService db, string userId)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        // Sich selbst löschen verhindern
        var currentUserId = ctx.GetUserId();
        if (currentUserId == userId)
        {
            ctx.Response.StatusCode = 400;
            await ctx.Response.WriteAsJsonAsync(new { error = "Du kannst dich nicht selbst löschen" });
            return;
        }

        var user = await db.GetUser(userId);
        if (user == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzer nicht gefunden" });
            return;
        }

        await db.DeleteUser(userId);
        await ctx.Response.WriteAsJsonAsync(new { ok = true });
    }

    private static async System.Threading.Tasks.Task HandleImpersonate(HttpContext ctx, DatabaseService db, AuthService auth, string userId)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        var user = await db.GetUser(userId);
        if (user == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzer nicht gefunden" });
            return;
        }

        // Token für den Zieluser erstellen und als Cookie setzen
        var token = auth.CreateToken(user.UserId);

        ctx.Response.Cookies.Append("gott_token", token, new CookieOptions
        {
            HttpOnly = true,
            SameSite = SameSiteMode.Strict,
            Path = "/",
            MaxAge = System.TimeSpan.FromDays(365)
        });

        await ctx.Response.WriteAsJsonAsync(new
        {
            userId = user.UserId,
            username = user.Username,
            displayName = user.DisplayName,
            isAdmin = user.IsAdmin
        });
    }

    private static async System.Threading.Tasks.Task HandleLoginLink(HttpContext ctx, DatabaseService db, AuthService auth, string userId)
    {
        if (!ctx.IsAdmin())
        {
            ctx.Response.StatusCode = 403;
            await ctx.Response.WriteAsJsonAsync(new { error = "Admin access required" });
            return;
        }

        var user = await db.GetUser(userId);
        if (user == null)
        {
            ctx.Response.StatusCode = 404;
            await ctx.Response.WriteAsJsonAsync(new { error = "Benutzer nicht gefunden" });
            return;
        }

        var token = auth.CreateToken(user.UserId);

        await ctx.Response.WriteAsJsonAsync(new { token });
    }
}