using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;

namespace Chatbeep.Sdk;

public class ChatbeepClient
{
    private readonly HttpClient _httpClient;
    private readonly string? _token;

    public ChatbeepClient(string apiBase, string? token = null, HttpClient? httpClient = null)
    {
        _token = token;
        _httpClient = httpClient ?? new HttpClient();
        _httpClient.BaseAddress = new Uri(apiBase.TrimEnd('/'));
        _httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    }

    public Task<JsonDocument> HealthAsync()
    {
        return SendAsync("/health");
    }

    public Task<JsonDocument> WidgetConfigAsync(string installationToken)
    {
        return SendAsync($"/widget/config/{installationToken}");
    }

    public Task<JsonDocument> WidgetInstallationHealthAsync(string installationToken, string? currentUrl = null)
    {
        return SendAsync($"/widget/installations/{installationToken}/health", query: currentUrl is null
            ? null
            : new Dictionary<string, string?> { ["current_url"] = currentUrl });
    }

    public Task<JsonDocument> WidgetPingAsync(object payload)
    {
        return SendAsync("/widget/ping", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> UpsertWidgetVisitorAsync(object payload)
    {
        return SendAsync("/widget/visitors", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> CreateWidgetConversationAsync(object payload)
    {
        return SendAsync("/widget/conversations", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> GetWidgetConversationMessagesAsync(string conversation, string widgetToken, IDictionary<string, string?>? query = null)
    {
        query ??= new Dictionary<string, string?>();
        query["token"] = widgetToken;

        return SendAsync($"/widget/conversations/{conversation}/messages", query: query);
    }

    public Task<JsonDocument> SendWidgetConversationMessageAsync(string conversation, object payload)
    {
        return SendAsync($"/widget/conversations/{conversation}/messages", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> StartWidgetVerificationAsync(string conversation, object payload)
    {
        return SendAsync($"/widget/conversations/{conversation}/verification/start", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> ConfirmWidgetVerificationAsync(string conversation, object payload)
    {
        return SendAsync($"/widget/conversations/{conversation}/verification/confirm", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> MobileLoginAsync(object payload)
    {
        return SendAsync("/mobile/login", HttpMethod.Post, payload);
    }

    public Task<JsonDocument> MobileMeAsync()
    {
        return SendAsync("/mobile/me", auth: true);
    }

    public Task<JsonDocument> MobileConversationsAsync(IDictionary<string, string?>? query = null)
    {
        return SendAsync("/mobile/conversations", query: query, auth: true);
    }

    public Task<JsonDocument> MobileConversationAsync(string conversation)
    {
        return SendAsync($"/mobile/conversations/{conversation}", auth: true);
    }

    public Task<JsonDocument> SendMobileConversationMessageAsync(string conversation, object payload)
    {
        return SendAsync($"/mobile/conversations/{conversation}/messages", HttpMethod.Post, payload, auth: true);
    }

    public Task<JsonDocument> AssignMobileConversationAsync(string conversation, object payload)
    {
        return SendAsync($"/mobile/conversations/{conversation}/assign", HttpMethod.Post, payload, auth: true);
    }

    public Task<JsonDocument> TransferMobileConversationAsync(string conversation, object payload)
    {
        return SendAsync($"/mobile/conversations/{conversation}/transfer", HttpMethod.Post, payload, auth: true);
    }

    public Task<JsonDocument> CloseMobileConversationAsync(string conversation, object? payload = null)
    {
        return SendAsync($"/mobile/conversations/{conversation}/close", HttpMethod.Post, payload ?? new { }, auth: true);
    }

    private async Task<JsonDocument> SendAsync(
        string path,
        HttpMethod? method = null,
        object? payload = null,
        IDictionary<string, string?>? query = null,
        bool auth = false)
    {
        method ??= HttpMethod.Get;
        var uri = path;

        if (query is { Count: > 0 })
        {
            var suffix = string.Join("&", query
                .Where(item => !string.IsNullOrWhiteSpace(item.Value))
                .Select(item => $"{Uri.EscapeDataString(item.Key)}={Uri.EscapeDataString(item.Value ?? string.Empty)}"));

            if (!string.IsNullOrWhiteSpace(suffix))
            {
                uri = $"{path}?{suffix}";
            }
        }

        var request = new HttpRequestMessage(method, uri);

        if (auth && !string.IsNullOrWhiteSpace(_token))
        {
            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", _token);
        }

        if (payload is not null)
        {
            request.Content = new StringContent(
                JsonSerializer.Serialize(payload),
                Encoding.UTF8,
                "application/json");
        }

        var response = await _httpClient.SendAsync(request);
        response.EnsureSuccessStatusCode();

        return JsonDocument.Parse(await response.Content.ReadAsStringAsync());
    }
}