using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using Flawless.Communication.Shared;
using Flawless.Server.Models;
using Microsoft.EntityFrameworkCore;

namespace Flawless.Server.Services;

public class WebhookService(
    SettingFacade settings,
    AppDbContext context,
    IHttpClientFactory httpFactory,
    ILogger<WebhookService> logger)
{
    public async Task AddWebhookAsync(Repository repo, string targetUrl, WebhookEventType eventType, string? secret)
    {
        if (string.IsNullOrWhiteSpace(targetUrl) || !Uri.TryCreate(targetUrl, UriKind.Absolute, out _))
            throw new ArgumentException("No valid target URL provided");
        
        var webhook = new Webhook {
            Repository = repo,
            TargetUrl = targetUrl,
            EventType = eventType,
            Secret = secret,
            IsActive = true
        };
        
        await context.Webhooks.AddAsync(webhook);
        await context.SaveChangesAsync();
    }
    
    public async Task ToggleWebhookAsync(Repository repo, int webhookId, bool activated)
    {
        var hook = await context.Webhooks
            .Include(x => x.Repository)
            .FirstOrDefaultAsync(x => x.Id == webhookId);

        if (hook == null || hook.Repository != repo) return;
    
        if (hook.IsActive == activated) return;
        
        hook.IsActive = activated;
        context.Webhooks.Update(hook);
        await context.SaveChangesAsync();
    }
    
    public async Task DeleteWebhookAsync(Repository repo, int webhookId)
    {
        var hook = await context.Webhooks
            .Include(x => x.Repository)
            .FirstOrDefaultAsync(x => x.Id == webhookId);
        
        if (hook == null || hook.Repository != repo) return;
    
        context.Webhooks.Remove(hook);
        await context.SaveChangesAsync();
    }
    
    public async Task<IEnumerable<Webhook>> GetWebhooksAsync(Repository repo)
    {
        return await context.Webhooks
            .Where(w => w.Repository == repo)
            .ToListAsync();
    }

    public async Task TriggerWebhooksAsync(Repository repo, WebhookEventType eventType, object payload)
    {
        if (!settings.UseWebHook) return;

        var hooks = await context.Webhooks
            .Where(w => w.Repository == repo && w.EventType == eventType && w.IsActive)
            .ToListAsync();

        using var client = httpFactory.CreateClient();
        client.Timeout = TimeSpan.FromSeconds(settings.WebhookTimeout);

        foreach (var hook in hooks)
        {
            for (var retry = 0; retry < settings.WebhookMaxRetries; retry++)
            {
                try
                {
                    var content = new StringContent(JsonSerializer.Serialize(payload), 
                        Encoding.UTF8, "application/json");
                    
                    if (hook.Secret != null)
                    {
                        var signature = HMACSHA256.HashData(
                            Encoding.UTF8.GetBytes(hook.Secret),
                            await content.ReadAsByteArrayAsync());

                        content.Headers.Add("X-Signature", $"sha256={Convert.ToHexString(signature)}");
                    }

                    var response = await client.PostAsync(hook.TargetUrl, content);
                    if (response.IsSuccessStatusCode) break;
                    
                    logger.LogWarning($"Webhook {hook.Id} Failed：{response.StatusCode}");
                    await Task.Delay(1000 * (int)Math.Pow(2, retry)); // 指数退避
                }
                catch (Exception ex)
                {
                    logger.LogError(ex, $"Webhook {hook.Id} Failed for {retry + 1} times.");
                    if (retry == settings.WebhookMaxRetries - 1)
                        await DeactivateFailedWebhook(hook);
                }
            }
        }
    }

    private async Task DeactivateFailedWebhook(Webhook hook)
    {
        hook.IsActive = false;
        context.Webhooks.Update(hook);
        await context.SaveChangesAsync();
    }
}