using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.AI;
using GeminiDotnet;
using GeminiDotnet.Extensions.AI;
using NexusReader.Infrastructure.Persistence;
using NexusReader.Application.Abstractions.Services;
using NexusReader.Infrastructure.Services;
using NexusReader.Infrastructure.Configuration;
using Polly;
using Polly.Retry;

namespace NexusReader.Infrastructure;

public static class DependencyInjection
{
    public static IServiceCollection AddInfrastructure(this IServiceCollection services, IConfiguration configuration)
    {
        var connectionString = configuration.GetConnectionString("SqliteConnection") ?? "Data Source=nexus.db";
        services.AddDbContext<AppDbContext>(options =>
            options.UseSqlite(connectionString));

        services.Configure<AiSettings>(configuration.GetSection(AiSettings.SectionName));
        var aiSettings = configuration.GetSection(AiSettings.SectionName).Get<AiSettings>() ?? new AiSettings();

        if (string.IsNullOrWhiteSpace(aiSettings.ApiKey) || aiSettings.ApiKey == "PLACEHOLDER")
        {
            // We don't throw here to allow the app to start, but services using AI will fail gracefully
        }

        services.AddResiliencePipeline("ai-retry", builder =>
        {
            builder.AddRetry(new RetryStrategyOptions
            {
                ShouldHandle = new PredicateBuilder().Handle<Exception>(ex => 
                    ex.Message.Contains("429") || ex.Message.Contains("Too Many Requests") || ex.Message.Contains("quota")),
                BackoffType = DelayBackoffType.Exponential,
                UseJitter = true,
                MaxRetryAttempts = aiSettings.RetryAttempts,
                Delay = TimeSpan.FromSeconds(2)
            });
        });

        services.AddChatClient(new GeminiChatClient(new GeminiClientOptions 
        { 
            ApiKey = aiSettings.ApiKey, 
            ModelId = aiSettings.Model 
        }));

        services.AddScoped<IKnowledgeService, KnowledgeService>();
        services.AddTransient<IAiGenerateQuizService, FakeAiGenerateQuizService>();
        services.AddTransient<IEpubService, EpubService>();
        return services;
    }
}