using ManagerService.Controllers;
using ManagerService.Data;
using ManagerService.DTOs;
using ManagerService.Services;
using ManagerService.Tests.Infrastructure;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging.Abstractions;
using Moq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Xunit;

namespace ManagerService.Tests.Controllers
{
    public class AiControllerTests
    {
        private static readonly AiChatResponse FakeResponse = new AiChatResponse { Reply = "OK", TokensUsed = 42 };

        private AiController BuildController(MyInfoMateDbContext db, Mock<IAssistantService>? mockService = null)
        {
            mockService ??= new Mock<IAssistantService>();
            mockService
                .Setup(s => s.ChatAsync(It.IsAny<AiChatRequest>()))
                .ReturnsAsync(FakeResponse);

            return new AiController(mockService.Object, db, NullLogger<AiController>.Instance);
        }

        private static AiChatRequest MakeRequest(string instanceId, AppType appType = AppType.Tablet) =>
            new AiChatRequest { InstanceId = instanceId, AppType = appType, Message = "Bonjour" };

        // ── FORBID CASES ─────────────────────────────────────────────────────

        [Fact]
        public async Task Chat_InstanceNotFound_ReturnsForbid()
        {
            using var db = DbContextFactory.Create();

            var result = await BuildController(db).Chat(MakeRequest("unknown"));

            Assert.IsType<ForbidResult>(result);
        }

        [Fact]
        public async Task Chat_InstanceAssistantDisabled_ReturnsForbid()
        {
            using var db = DbContextFactory.Create();
            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = false, DateCreation = DateTime.UtcNow
            });
            db.ApplicationInstances.Add(new ApplicationInstance
            {
                Id = "ai1", InstanceId = "i1", AppType = AppType.Tablet, IsAssistant = true,
                Languages = new List<string>()
            });
            db.SaveChanges();

            var result = await BuildController(db).Chat(MakeRequest("i1"));

            Assert.IsType<ForbidResult>(result);
        }

        [Fact]
        public async Task Chat_AppInstanceAssistantDisabled_ReturnsForbid()
        {
            using var db = DbContextFactory.Create();
            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = true, DateCreation = DateTime.UtcNow
            });
            db.ApplicationInstances.Add(new ApplicationInstance
            {
                Id = "ai1", InstanceId = "i1", AppType = AppType.Tablet, IsAssistant = false,
                Languages = new List<string>()
            });
            db.SaveChanges();

            var result = await BuildController(db).Chat(MakeRequest("i1"));

            Assert.IsType<ForbidResult>(result);
        }

        [Fact]
        public async Task Chat_NoAppInstance_ReturnsForbid()
        {
            using var db = DbContextFactory.Create();
            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = true, DateCreation = DateTime.UtcNow
            });
            db.SaveChanges();

            var result = await BuildController(db).Chat(MakeRequest("i1"));

            Assert.IsType<ForbidResult>(result);
        }

        // ── QUOTA COUNTER ────────────────────────────────────────────────────

        [Fact]
        public async Task Chat_FirstRequestOfMonth_ResetsCounterAndAddsTokensUsed()
        {
            using var db = DbContextFactory.Create();
            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = true, DateCreation = DateTime.UtcNow,
                AiTokensThisMonth = 99, AiUsageMonthKey = "2020-01"
            });
            db.ApplicationInstances.Add(new ApplicationInstance
            {
                Id = "ai1", InstanceId = "i1", AppType = AppType.Tablet, IsAssistant = true,
                Languages = new List<string>()
            });
            db.SaveChanges();

            await BuildController(db).Chat(MakeRequest("i1"));

            var inst = db.Instances.First();
            Assert.Equal(42, inst.AiTokensThisMonth);
            Assert.Equal(DateTime.UtcNow.ToString("yyyy-MM"), inst.AiUsageMonthKey);
        }

        [Fact]
        public async Task Chat_SameMonth_AddsTokensUsedToCounter()
        {
            using var db = DbContextFactory.Create();
            var monthKey = DateTime.UtcNow.ToString("yyyy-MM");
            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = true, DateCreation = DateTime.UtcNow,
                AiTokensThisMonth = 3, AiUsageMonthKey = monthKey
            });
            db.ApplicationInstances.Add(new ApplicationInstance
            {
                Id = "ai1", InstanceId = "i1", AppType = AppType.Tablet, IsAssistant = true,
                Languages = new List<string>()
            });
            db.SaveChanges();

            await BuildController(db).Chat(MakeRequest("i1"));

            Assert.Equal(45, db.Instances.First().AiTokensThisMonth);
        }

        [Fact]
        public async Task Chat_QuotaAlreadyReached_ReturnsTooManyRequestsWithoutCallingAssistantService()
        {
            using var db = DbContextFactory.Create();
            var monthKey = DateTime.UtcNow.ToString("yyyy-MM");
            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = true, DateCreation = DateTime.UtcNow,
                AiTokensThisMonth = 100, AiTokensPerMonth = 100, AiUsageMonthKey = monthKey
            });
            db.ApplicationInstances.Add(new ApplicationInstance
            {
                Id = "ai1", InstanceId = "i1", AppType = AppType.Tablet, IsAssistant = true,
                Languages = new List<string>()
            });
            db.SaveChanges();

            var mockService = new Mock<IAssistantService>();
            mockService.Setup(s => s.ChatAsync(It.IsAny<AiChatRequest>())).ReturnsAsync(FakeResponse);

            var result = await BuildController(db, mockService).Chat(MakeRequest("i1"));

            var status = Assert.IsType<ObjectResult>(result);
            Assert.Equal(429, status.StatusCode);
            mockService.Verify(s => s.ChatAsync(It.IsAny<AiChatRequest>()), Times.Never);
        }

        // ── NOMINAL ──────────────────────────────────────────────────────────

        [Fact]
        public async Task Chat_Success_CallsAssistantServiceAndReturns200()
        {
            using var db = DbContextFactory.Create();
            var mockService = new Mock<IAssistantService>();
            mockService.Setup(s => s.ChatAsync(It.IsAny<AiChatRequest>())).ReturnsAsync(FakeResponse);

            db.Instances.Add(new Instance
            {
                Id = "i1", Name = "Musée", IsAssistant = true, DateCreation = DateTime.UtcNow,
                AiUsageMonthKey = DateTime.UtcNow.ToString("yyyy-MM")
            });
            db.ApplicationInstances.Add(new ApplicationInstance
            {
                Id = "ai1", InstanceId = "i1", AppType = AppType.Tablet, IsAssistant = true,
                Languages = new List<string>()
            });
            db.SaveChanges();

            var result = await BuildController(db, mockService).Chat(MakeRequest("i1"));

            var ok = Assert.IsType<OkObjectResult>(result);
            Assert.Equal(FakeResponse, ok.Value);
            mockService.Verify(s => s.ChatAsync(It.IsAny<AiChatRequest>()), Times.Once);
        }
    }
}