using System.Net.Http.Json;
using System.Text.Json.Serialization;
using Microsoft.JSInterop;

namespace Web.Services;

public class AuthService
{
    private readonly string _graphqlEndpoint;
    private readonly HttpClient _http;
    private readonly IJSRuntime? _jsRuntime;
    private readonly NetworkStatusService _networkStatus;

    public AuthService(HttpClient http, NetworkStatusService networkStatus, IServiceProvider serviceProvider)
    {
        _http = http;
        _networkStatus = networkStatus;
        _jsRuntime = serviceProvider.GetService(typeof(IJSRuntime)) as IJSRuntime;
        _graphqlEndpoint = http.BaseAddress != null && http.BaseAddress.Port == 5256
            ? "/graphql"
            : "http://localhost:5256/graphql";
    }

    public bool IsLoggedIn => !string.IsNullOrEmpty(AuthToken);
    public string? CurrentUsername { get; private set; }
    public string? AuthToken { get; private set; }

    public event Action? AuthStateChanged;

    public async Task InitializeAsync()
    {
        if (_jsRuntime != null)
            try
            {
                var storedToken = await _jsRuntime.InvokeAsync<string?>("localStorage.getItem", "chrono_auth_token");
                var storedUser = await _jsRuntime.InvokeAsync<string?>("localStorage.getItem", "chrono_auth_user");
                if (!string.IsNullOrEmpty(storedToken) && !string.IsNullOrEmpty(storedUser))
                {
                    AuthToken = storedToken;
                    CurrentUsername = storedUser;
                    AuthStateChanged?.Invoke();
                }
            }
            catch
            {
                // LocalStorage not available in testing or SSR
            }
    }

    public async Task<AuthResult> LoginAsync(string username, string password)
    {
        if (!_networkStatus.IsOnline)
            return new AuthResult { Success = false, Message = "Cannot login while offline." };

        try
        {
            var request = new GraphQLRequest
            {
                Query = @"mutation Login($username: String!, $password: String!) {
                    login(username: $username, password: $password) {
                        success
                        token
                        username
                        message
                    }
                }",
                Variables = new Dictionary<string, object>
                {
                    ["username"] = username,
                    ["password"] = password
                }
            };

            var response = await SendGraphQLAsync<LoginResponseData>(request);
            var payload = response?.Data?.Login;
            if (payload != null && payload.Success && !string.IsNullOrEmpty(payload.Token))
            {
                AuthToken = payload.Token;
                CurrentUsername = payload.Username ?? username;

                if (_jsRuntime != null)
                    try
                    {
                        await _jsRuntime.InvokeVoidAsync("localStorage.setItem", "chrono_auth_token", AuthToken);
                        await _jsRuntime.InvokeVoidAsync("localStorage.setItem", "chrono_auth_user", CurrentUsername);
                    }
                    catch
                    {
                    }

                AuthStateChanged?.Invoke();
                return new AuthResult { Success = true, Message = payload.Message ?? "Login successful" };
            }

            return new AuthResult { Success = false, Message = payload?.Message ?? "Invalid username or password." };
        }
        catch (Exception ex)
        {
            return new AuthResult { Success = false, Message = $"Login error: {ex.Message}" };
        }
    }

    public async Task LogoutAsync()
    {
        AuthToken = null;
        CurrentUsername = null;

        if (_jsRuntime != null)
            try
            {
                await _jsRuntime.InvokeVoidAsync("localStorage.removeItem", "chrono_auth_token");
                await _jsRuntime.InvokeVoidAsync("localStorage.removeItem", "chrono_auth_user");
            }
            catch
            {
            }

        AuthStateChanged?.Invoke();
    }

    public void SetAuth(string username, string token)
    {
        CurrentUsername = username;
        AuthToken = token;
        AuthStateChanged?.Invoke();
    }

    private async Task<GraphQLResponse<T>?> SendGraphQLAsync<T>(GraphQLRequest request)
    {
        try
        {
            var httpResponse = await _http.PostAsJsonAsync(_graphqlEndpoint, request);
            if (httpResponse.IsSuccessStatusCode)
                return await httpResponse.Content.ReadFromJsonAsync<GraphQLResponse<T>>();

            if (_graphqlEndpoint == "/graphql")
            {
                var fallbackResponse = await _http.PostAsJsonAsync("http://localhost:5256/graphql", request);
                if (fallbackResponse.IsSuccessStatusCode)
                    return await fallbackResponse.Content.ReadFromJsonAsync<GraphQLResponse<T>>();
            }
        }
        catch
        {
            try
            {
                var fallbackResponse = await _http.PostAsJsonAsync("http://localhost:5256/graphql", request);
                if (fallbackResponse.IsSuccessStatusCode)
                    return await fallbackResponse.Content.ReadFromJsonAsync<GraphQLResponse<T>>();
            }
            catch
            {
            }
        }

        return null;
    }

    public class AuthResult
    {
        public bool Success { get; set; }
        public string Message { get; set; } = string.Empty;
    }

    private class GraphQLRequest
    {
        [JsonPropertyName("query")] public string Query { get; set; } = string.Empty;

        [JsonPropertyName("variables")] public Dictionary<string, object>? Variables { get; set; }
    }

    private class GraphQLResponse<T>
    {
        [JsonPropertyName("data")] public T? Data { get; set; }

        [JsonPropertyName("errors")] public List<GraphQLError>? Errors { get; set; }
    }

    private class GraphQLError
    {
        [JsonPropertyName("message")] public string Message { get; set; } = string.Empty;
    }

    private class LoginResponseData
    {
        [JsonPropertyName("login")] public LoginPayloadData? Login { get; set; }
    }

    private class LoginPayloadData
    {
        [JsonPropertyName("success")] public bool Success { get; set; }

        [JsonPropertyName("token")] public string? Token { get; set; }

        [JsonPropertyName("username")] public string? Username { get; set; }

        [JsonPropertyName("message")] public string? Message { get; set; }
    }
}