using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using RpgRoller.Data;
using RpgRoller.Domain;
using RpgRoller.Services;

namespace RpgRoller.Tests;

public sealed class GameServiceTests
{
    [Fact]
    public void Register_ValidatesRequiredFieldsAndDuplicates()
    {
        using var harness = CreateHarness();
        var service = harness.Service;

        var invalidUsername = service.Register(new RegisterCommand("", "Password123", "Display"));
        var invalidDisplay = service.Register(new RegisterCommand("user", "Password123", ""));
        var invalidPassword = service.Register(new RegisterCommand("user", "short", "Display"));
        var valid = service.Register(new RegisterCommand("user", "Password123", "Display"));
        var duplicate = service.Register(new RegisterCommand("user", "Password123", "Display 2"));

        Assert.False(invalidUsername.Succeeded);
        Assert.False(invalidDisplay.Succeeded);
        Assert.False(invalidPassword.Succeeded);
        Assert.True(valid.Succeeded);
        Assert.False(duplicate.Succeeded);
    }

    [Fact]
    public void Login_ValidatesCredentialsAndSessionLookup()
    {
        using var harness = CreateHarness();
        var service = harness.Service;
        service.Register(new RegisterCommand("user", "Password123", "Display"));

        var invalidUser = service.Login(new LoginCommand("missing", "Password123"));
        var invalidPassword = service.Login(new LoginCommand("user", "bad-password"));
        var valid = service.Login(new LoginCommand("user", "Password123"));

        Assert.False(invalidUser.Succeeded);
        Assert.False(invalidPassword.Succeeded);
        Assert.True(valid.Succeeded);

        var sessionUser = service.GetUserBySession(valid.Value.SessionToken);
        Assert.NotNull(sessionUser);

        service.Logout(valid.Value.SessionToken);
        Assert.Null(service.GetUserBySession(valid.Value.SessionToken));
    }

    [Fact]
    public void Login_RehashesPasswordWhenHasherRequestsIt()
    {
        var hasher = new RehashingPasswordHasher();
        using var harness = CreateHarness(hasher);
        var service = harness.Service;

        service.Register(new RegisterCommand("user", "Password123", "Display"));
        var login = service.Login(new LoginCommand("user", "Password123"));

        Assert.True(login.Succeeded);
        Assert.Equal(2, hasher.HashCalls);
    }

    [Fact]
    public void CampaignAndCharacterOperations_CheckUnauthorizedAndNotFoundCases()
    {
        using var harness = CreateHarness();
        var service = harness.Service;

        var unauthorizedCampaign = service.CreateCampaign("missing", new CreateCampaignCommand("Name", "d6"));
        Assert.False(unauthorizedCampaign.Succeeded);

        service.Register(new RegisterCommand("gm", "Password123", "GM"));
        var gmSession = GetValue(service.Login(new LoginCommand("gm", "Password123"))).SessionToken;
        var campaign = GetValue(service.CreateCampaign(gmSession, new CreateCampaignCommand("Name", "d6")));

        var invalidRuleset = service.CreateCampaign(gmSession, new CreateCampaignCommand("Name 2", "unknown"));
        Assert.False(invalidRuleset.Succeeded);

        var noCampaignCharacter = service.CreateCharacter(gmSession, new CreateCharacterCommand("Hero", Guid.NewGuid()));
        Assert.False(noCampaignCharacter.Succeeded);

        var character = GetValue(service.CreateCharacter(gmSession, new CreateCharacterCommand("Hero", campaign.Id)));

        var missingCharacterActivate = service.ActivateCharacter(gmSession, Guid.NewGuid());
        Assert.False(missingCharacterActivate.Succeeded);

        var activateSuccess = service.ActivateCharacter(gmSession, character.Id);
        Assert.True(activateSuccess.Succeeded);

        var currentCharacters = service.GetCurrentCampaignCharacters(gmSession);
        Assert.True(currentCharacters.Succeeded);
        Assert.Single(GetValue(currentCharacters));

        var missingCampaignGet = service.GetCampaign(gmSession, Guid.NewGuid());
        Assert.False(missingCampaignGet.Succeeded);
    }

    [Fact]
    public void CharacterSkillAndRollOperations_CheckAuthorizationAndValidationBranches()
    {
        using var harness = CreateHarness(3, 4, 5, 6);
        var service = harness.Service;
        service.Register(new RegisterCommand("gm", "Password123", "GM"));
        service.Register(new RegisterCommand("owner", "Password123", "Owner"));
        service.Register(new RegisterCommand("other", "Password123", "Other"));

        var gmSession = GetValue(service.Login(new LoginCommand("gm", "Password123"))).SessionToken;
        var ownerSession = GetValue(service.Login(new LoginCommand("owner", "Password123"))).SessionToken;
        var otherSession = GetValue(service.Login(new LoginCommand("other", "Password123"))).SessionToken;

        var campaign = GetValue(service.CreateCampaign(gmSession, new CreateCampaignCommand("Main", "dnd5e")));
        var character = GetValue(service.CreateCharacter(ownerSession, new CreateCharacterCommand("Owner Char", campaign.Id)));

        var noPermissionUpdate = service.UpdateCharacter(otherSession, character.Id, new UpdateCharacterCommand("Renamed", campaign.Id));
        Assert.False(noPermissionUpdate.Succeeded);

        var invalidCharacterName = service.UpdateCharacter(ownerSession, character.Id, new UpdateCharacterCommand("", campaign.Id));
        Assert.False(invalidCharacterName.Succeeded);

        var missingTargetCampaign = service.UpdateCharacter(ownerSession, character.Id, new UpdateCharacterCommand("Renamed", Guid.NewGuid()));
        Assert.False(missingTargetCampaign.Succeeded);

        var noSkillName = service.CreateSkill(ownerSession, character.Id, new CreateSkillCommand("", "1d20"));
        Assert.False(noSkillName.Succeeded);

        var invalidExpression = service.CreateSkill(ownerSession, character.Id, new CreateSkillCommand("Skill", "5D+4"));
        Assert.False(invalidExpression.Succeeded);

        var skill = GetValue(service.CreateSkill(ownerSession, character.Id, new CreateSkillCommand("Skill", "1d20+2")));

        var missingSkillUpdate = service.UpdateSkill(ownerSession, Guid.NewGuid(), new UpdateSkillCommand("X", "1d20"));
        Assert.False(missingSkillUpdate.Succeeded);

        var forbiddenSkillUpdate = service.UpdateSkill(otherSession, skill.Id, new UpdateSkillCommand("X", "1d20"));
        Assert.False(forbiddenSkillUpdate.Succeeded);

        var gmSkillUpdate = service.UpdateSkill(gmSession, skill.Id, new UpdateSkillCommand("GM Edit", "2d6+1"));
        Assert.True(gmSkillUpdate.Succeeded);

        var missingRoll = service.RollSkill(ownerSession, Guid.NewGuid(), new RollSkillCommand("public"));
        Assert.False(missingRoll.Succeeded);

        var invalidVisibility = service.RollSkill(ownerSession, skill.Id, new RollSkillCommand("hidden"));
        Assert.False(invalidVisibility.Succeeded);

        var forbiddenRoll = service.RollSkill(otherSession, skill.Id, new RollSkillCommand("public"));
        Assert.False(forbiddenRoll.Succeeded);

        var privateRoll = service.RollSkill(ownerSession, skill.Id, new RollSkillCommand("private"));
        var publicRoll = service.RollSkill(ownerSession, skill.Id, new RollSkillCommand("public"));
        Assert.True(privateRoll.Succeeded);
        Assert.True(publicRoll.Succeeded);

        var ownerLog = service.GetCampaignLog(ownerSession, campaign.Id);
        var gmLog = service.GetCampaignLog(gmSession, campaign.Id);
        var outsiderLog = service.GetCampaignLog(otherSession, campaign.Id);

        Assert.Equal(2, GetValue(ownerLog).Count);
        Assert.Equal(2, GetValue(gmLog).Count);
        Assert.False(outsiderLog.Succeeded);

        var version = service.GetCampaignVersion(ownerSession, campaign.Id);
        var missingVersion = service.GetCampaignVersion(ownerSession, Guid.NewGuid());
        Assert.True(version.Succeeded);
        Assert.False(missingVersion.Succeeded);
    }

    [Fact]
    public void CurrentCampaignCharacters_ReturnsNoActiveCharacterWhenUnset()
    {
        using var harness = CreateHarness();
        var service = harness.Service;
        service.Register(new RegisterCommand("user", "Password123", "User"));
        var sessionToken = GetValue(service.Login(new LoginCommand("user", "Password123"))).SessionToken;

        var result = service.GetCurrentCampaignCharacters(sessionToken);
        Assert.False(result.Succeeded);
    }

    [Fact]
    public void GetCampaigns_ReturnsOwnedAndParticipatingCampaigns()
    {
        using var harness = CreateHarness();
        var service = harness.Service;
        service.Register(new RegisterCommand("gm", "Password123", "GM"));
        service.Register(new RegisterCommand("player", "Password123", "Player"));
        var gmSession = GetValue(service.Login(new LoginCommand("gm", "Password123"))).SessionToken;
        var playerSession = GetValue(service.Login(new LoginCommand("player", "Password123"))).SessionToken;

        var gmCampaign = GetValue(service.CreateCampaign(gmSession, new CreateCampaignCommand("Owned", "d6")));
        _ = GetValue(service.CreateCampaign(gmSession, new CreateCampaignCommand("Owned 2", "d6")));
        _ = service.CreateCharacter(playerSession, new CreateCharacterCommand("Joiner", gmCampaign.Id));

        var playerCampaigns = service.GetCampaigns(playerSession);
        Assert.True(playerCampaigns.Succeeded);
        var campaigns = GetValue(playerCampaigns);
        Assert.Single(campaigns);
        Assert.Equal(gmCampaign.Id, campaigns[0].Id);
    }

    [Fact]
    public void ServiceGuardAndPersistenceBranches_AreHandled()
    {
        using var harness = CreateHarness(2, 3, 4);
        var service = harness.Service;

        var invalidCredentials = service.Login(new LoginCommand("", ""));
        Assert.False(invalidCredentials.Succeeded);

        service.Logout("missing-session");

        service.Register(new RegisterCommand("gm", "Password123", "GM"));
        service.Register(new RegisterCommand("owner", "Password123", "Owner"));
        service.Register(new RegisterCommand("other", "Password123", "Other"));

        var gmSession = GetValue(service.Login(new LoginCommand("gm", "Password123"))).SessionToken;
        var ownerSession = GetValue(service.Login(new LoginCommand("owner", "Password123"))).SessionToken;
        var otherSession = GetValue(service.Login(new LoginCommand("other", "Password123"))).SessionToken;

        var campaign = GetValue(service.CreateCampaign(gmSession, new CreateCampaignCommand("Main", "d6")));
        var ownerCharacter = GetValue(service.CreateCharacter(ownerSession, new CreateCharacterCommand("Owner Character", campaign.Id)));

        Assert.False(service.GetMe(string.Empty).Succeeded);
        Assert.False(service.CreateCampaign(gmSession, new CreateCampaignCommand("", "d6")).Succeeded);
        Assert.False(service.GetCampaigns(string.Empty).Succeeded);
        Assert.False(service.CreateCharacter(ownerSession, new CreateCharacterCommand("", campaign.Id)).Succeeded);
        Assert.False(service.CreateCharacter(string.Empty, new CreateCharacterCommand("Name", campaign.Id)).Succeeded);
        Assert.False(service.UpdateCharacter(string.Empty, ownerCharacter.Id, new UpdateCharacterCommand("Renamed", campaign.Id)).Succeeded);
        Assert.False(service.UpdateCharacter(ownerSession, Guid.NewGuid(), new UpdateCharacterCommand("Renamed", campaign.Id)).Succeeded);
        Assert.False(service.ActivateCharacter(string.Empty, ownerCharacter.Id).Succeeded);
        Assert.False(service.ActivateCharacter(gmSession, ownerCharacter.Id).Succeeded);
        Assert.False(service.GetCurrentCampaignCharacters(string.Empty).Succeeded);
        Assert.False(service.CreateSkill(string.Empty, ownerCharacter.Id, new CreateSkillCommand("Stealth", "2D+1")).Succeeded);
        Assert.False(service.CreateSkill(ownerSession, Guid.NewGuid(), new CreateSkillCommand("Stealth", "2D+1")).Succeeded);
        Assert.False(service.CreateSkill(otherSession, ownerCharacter.Id, new CreateSkillCommand("Stealth", "2D+1")).Succeeded);

        using (var db = harness.CreateDbContext())
        {
            var ownerUser = db.Users.Single(u => u.UsernameNormalized == "OWNER");
            ownerUser.ActiveCharacterId = Guid.NewGuid();
            db.SaveChanges();
        }

        using var staleMeHarness = CreateHarnessFromPath(harness.DbPath, 2, 3, 4);
        var staleMeService = staleMeHarness.Service;

        var staleMe = GetValue(staleMeService.GetMe(ownerSession));
        Assert.Null(staleMe.ActiveCharacterId);
        Assert.Null(staleMe.CurrentCampaignId);

        Assert.True(staleMeService.ActivateCharacter(ownerSession, ownerCharacter.Id).Succeeded);
        var activeMe = GetValue(staleMeService.GetMe(ownerSession));
        Assert.Equal(ownerCharacter.Id, activeMe.ActiveCharacterId);
        Assert.Equal(campaign.Id, activeMe.CurrentCampaignId);

        using (var db = harness.CreateDbContext())
        {
            var staleOwner = db.Users.Single(u => u.UsernameNormalized == "OWNER");
            staleOwner.ActiveCharacterId = Guid.NewGuid();
            db.SaveChanges();
        }

        using var staleCurrentHarness = CreateHarnessFromPath(harness.DbPath, 2, 3, 4);
        var staleCurrentService = staleCurrentHarness.Service;

        var staleCurrentCampaign = staleCurrentService.GetCurrentCampaignCharacters(ownerSession);
        Assert.False(staleCurrentCampaign.Succeeded);
        using (var db = harness.CreateDbContext())
        {
            Assert.Null(db.Users.Single(u => u.UsernameNormalized == "OWNER").ActiveCharacterId);
        }

        var skill = GetValue(service.CreateSkill(ownerSession, ownerCharacter.Id, new CreateSkillCommand("Stealth", "2D+1")));
        Assert.False(service.UpdateSkill(ownerSession, skill.Id, new UpdateSkillCommand("", "2D+1")).Succeeded);
        Assert.False(service.UpdateSkill(string.Empty, skill.Id, new UpdateSkillCommand("Stealth", "2D+1")).Succeeded);
        Assert.False(service.UpdateSkill(ownerSession, skill.Id, new UpdateSkillCommand("Stealth", "bad")).Succeeded);
        Assert.False(service.RollSkill(string.Empty, skill.Id, new RollSkillCommand("public")).Succeeded);

        using (var db = harness.CreateDbContext())
        {
            var mutableSkill = db.Skills.Single(s => s.Id == skill.Id);
            mutableSkill.DiceRollDefinition = "bad";
            db.SaveChanges();
        }

        using var invalidExpressionHarness = CreateHarnessFromPath(harness.DbPath, 2, 3, 4);
        Assert.False(invalidExpressionHarness.Service.RollSkill(ownerSession, skill.Id, new RollSkillCommand("public")).Succeeded);
        Assert.False(service.GetCampaignLog(string.Empty, campaign.Id).Succeeded);
    }

    [Fact]
    public void GetCampaign_ForNonGm_ReturnsOnlyOwnedCharactersAndSkills()
    {
        using var harness = CreateHarness();
        var service = harness.Service;

        service.Register(new RegisterCommand("gm", "Password123", "GM"));
        service.Register(new RegisterCommand("owner", "Password123", "Owner"));
        service.Register(new RegisterCommand("other", "Password123", "Other"));

        var gmSession = GetValue(service.Login(new LoginCommand("gm", "Password123"))).SessionToken;
        var ownerSession = GetValue(service.Login(new LoginCommand("owner", "Password123"))).SessionToken;
        var otherSession = GetValue(service.Login(new LoginCommand("other", "Password123"))).SessionToken;

        var campaign = GetValue(service.CreateCampaign(gmSession, new CreateCampaignCommand("Main", "d6")));
        var ownerCharacter = GetValue(service.CreateCharacter(ownerSession, new CreateCharacterCommand("Owner Character", campaign.Id)));
        var otherCharacter = GetValue(service.CreateCharacter(otherSession, new CreateCharacterCommand("Other Character", campaign.Id)));

        var ownerSkill = GetValue(service.CreateSkill(ownerSession, ownerCharacter.Id, new CreateSkillCommand("Stealth", "2D+1")));
        _ = GetValue(service.CreateSkill(otherSession, otherCharacter.Id, new CreateSkillCommand("Perception", "1D+2")));

        var ownerView = GetValue(service.GetCampaign(ownerSession, campaign.Id));
        Assert.Single(ownerView.Characters);
        Assert.Equal(ownerCharacter.Id, ownerView.Characters[0].Id);
        Assert.Single(ownerView.Skills);
        Assert.Equal(ownerSkill.Id, ownerView.Skills[0].Id);
    }

    [Fact]
    public void DiceRules_CoversParsingAndMappingBranches()
    {
        Assert.Equal(RulesetKind.D6, DiceRules.TryParseRulesetId("d6"));
        Assert.Equal(RulesetKind.Dnd5e, DiceRules.TryParseRulesetId("dnd5e"));
        Assert.Null(DiceRules.TryParseRulesetId("unknown"));

        var d6 = DiceRules.ParseExpression(RulesetKind.D6, "5D+4");
        var dnd = DiceRules.ParseExpression(RulesetKind.Dnd5e, "2d12+2");
        var emptyExpression = DiceRules.ParseExpression(RulesetKind.Dnd5e, "");
        var badFormat = DiceRules.ParseExpression(RulesetKind.Dnd5e, "abc");
        var tooManyDice = DiceRules.ParseExpression(RulesetKind.D6, "51D+1");
        var tooManySides = DiceRules.ParseExpression(RulesetKind.Dnd5e, "1d1001");
        var tooLargeModifier = DiceRules.ParseExpression(RulesetKind.Dnd5e, "1d20+1001");
        var unknownRulesetExpression = DiceRules.ParseExpression((RulesetKind)99, "1d20+1");

        Assert.True(d6.Succeeded);
        Assert.True(dnd.Succeeded);
        Assert.False(emptyExpression.Succeeded);
        Assert.False(badFormat.Succeeded);
        Assert.False(tooManyDice.Succeeded);
        Assert.False(tooManySides.Succeeded);
        Assert.False(tooLargeModifier.Succeeded);
        Assert.False(unknownRulesetExpression.Succeeded);

        Assert.Equal("d6", DiceRules.ToRulesetId(RulesetKind.D6));
        Assert.Equal("dnd5e", DiceRules.ToRulesetId(RulesetKind.Dnd5e));
        Assert.Throws<ArgumentOutOfRangeException>(() => DiceRules.ToRulesetId((RulesetKind)99));
    }

    [Fact]
    public void RandomDiceRoller_ProducesValueWithinRange()
    {
        var roller = new RandomDiceRoller();
        for (var i = 0; i < 64; i += 1)
        {
            var value = roller.Roll(12);
            Assert.InRange(value, 1, 12);
        }
    }

    private static ServiceHarness CreateHarness(params int[] rollValues)
    {
        return CreateHarness(new PasswordHasher<UserAccount>(), rollValues);
    }

    private static ServiceHarness CreateHarness(IPasswordHasher<UserAccount> passwordHasher, params int[] rollValues)
    {
        var dbPath = Path.Combine(Path.GetTempPath(), $"rpgroller-servicetests-{Guid.NewGuid():N}.db");
        return CreateHarnessFromPath(dbPath, passwordHasher, rollValues);
    }

    private static ServiceHarness CreateHarnessFromPath(string dbPath, params int[] rollValues)
    {
        return CreateHarnessFromPath(dbPath, new PasswordHasher<UserAccount>(), rollValues);
    }

    private static ServiceHarness CreateHarnessFromPath(string dbPath, IPasswordHasher<UserAccount> passwordHasher, params int[] rollValues)
    {
        var options = new DbContextOptionsBuilder<RpgRollerDbContext>()
            .UseSqlite($"Data Source={dbPath}")
            .Options;

        using (var db = new RpgRollerDbContext(options))
        {
            db.Database.EnsureCreated();
        }

        var factory = new SqliteDbContextFactory(dbPath);
        var service = new GameService(factory, passwordHasher, new FixedDiceRoller(rollValues));
        return new ServiceHarness(service, factory, dbPath);
    }

    private static T GetValue<T>(ServiceResult<T> result)
    {
        Assert.True(result.Succeeded);
        Assert.NotNull(result.Value);
        return result.Value!;
    }

    private sealed class FixedDiceRoller : IDiceRoller
    {
        private readonly Queue<int> m_Values;

        public FixedDiceRoller(IEnumerable<int> values)
        {
            m_Values = new Queue<int>(values);
        }

        public int Roll(int sides)
        {
            var next = m_Values.Count > 0 ? m_Values.Dequeue() : 1;
            return Math.Clamp(next, 1, sides);
        }
    }

    private sealed class ServiceHarness : IDisposable
    {
        private readonly SqliteDbContextFactory m_Factory;

        public ServiceHarness(GameService service, SqliteDbContextFactory factory, string dbPath)
        {
            Service = service;
            m_Factory = factory;
            DbPath = dbPath;
        }

        public GameService Service { get; }
        public string DbPath { get; }

        public void Dispose()
        {
            m_Factory.Dispose();
        }

        public RpgRollerDbContext CreateDbContext()
        {
            return m_Factory.CreateDbContext();
        }
    }

    private sealed class SqliteDbContextFactory : IDbContextFactory<RpgRollerDbContext>, IDisposable
    {
        private readonly DbContextOptions<RpgRollerDbContext> m_Options;

        public SqliteDbContextFactory(string dbPath)
        {
            m_Options = new DbContextOptionsBuilder<RpgRollerDbContext>()
                .UseSqlite($"Data Source={dbPath}")
                .Options;
        }

        public RpgRollerDbContext CreateDbContext()
        {
            return new RpgRollerDbContext(m_Options);
        }

        public void Dispose()
        {
        }
    }

    private sealed class RehashingPasswordHasher : IPasswordHasher<UserAccount>
    {
        public int HashCalls { get; private set; }

        public string HashPassword(UserAccount user, string password)
        {
            HashCalls += 1;
            return $"hash:{HashCalls}:{password}";
        }

        public PasswordVerificationResult VerifyHashedPassword(UserAccount user, string hashedPassword, string providedPassword)
        {
            return providedPassword == "Password123"
                ? PasswordVerificationResult.SuccessRehashNeeded
                : PasswordVerificationResult.Failed;
        }
    }
}