using System.Reflection;
using System.Security.Claims;
using ERPCore.Controllers;
using ERPCore.Domain.Entities;
using ERPCore.Domain.Enums;
using ERPCore.Dtos.Search;
using ERPCore.Infra.Auth;
using ERPCore.Infra.Persistence;
using ERPCore.Repositories;
using ERPCore.Services;
using ERPCore.System.Errors;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.Routing;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
using Microsoft.Extensions.Caching.Memory;
using static ERPCore.Tests.TestSupport.BankDepositTestSupport;

namespace ERPCore.Tests;

/// <summary>
/// Permission coverage (Phase B): every API endpoint that changes data sits behind a permission, every permission the
/// controllers name actually exists in the seeded catalogue, HR data is gated, global search respects the role,
/// state-changing cookie requests need the CSRF token, and a branch-less person can't read every branch.
/// </summary>
public class PermissionCoverageTests
{
    // The seeded (HasData) rows live in the design-time model; the runtime model drops them.
    private static IEnumerable<IDictionary<string, object?>> Seed<T>(ErpDbContext db) =>
        Microsoft.EntityFrameworkCore.Infrastructure.AccessorExtensions.GetService<IDesignTimeModel>(db)
            .Model.FindEntityType(typeof(T))!.GetSeedData();

    // ---------------------------------------------------------------- controllers <-> permissions

    private static IEnumerable<Type> ApiControllers() =>
        typeof(ApiControllerBase).Assembly.GetTypes()
            .Where(t => !t.IsAbstract && typeof(ApiControllerBase).IsAssignableFrom(t));

    private static IEnumerable<string> NavPolicyNames(MemberInfo member) =>
        member.GetCustomAttributes<AuthorizeAttribute>(inherit: true)
            .Select(a => a.Policy)
            .Where(p => p is not null && p.StartsWith(NavPolicies.Prefix, StringComparison.Ordinal))!;

    private static bool IsReadOnly(MethodInfo m) =>
        m.GetCustomAttributes<HttpGetAttribute>().Any() && !m.GetCustomAttributes().OfType<Microsoft.AspNetCore.Mvc.Routing.HttpMethodAttribute>().Any(a => a is not HttpGetAttribute);

    /// <summary>Endpoints that deliberately sit behind the login door only: personal, or checked inside the service.</summary>
    private static readonly HashSet<string> OpenByDesign = new()
    {
        nameof(AuthController),            // sign-in, sessions, password: the person's own
        nameof(NavController),             // "what may I see": the person's own permissions
        nameof(NotificationsController),   // the person's own inbox
        nameof(SupportTicketsController),  // anyone may raise a ticket; the service scopes by owner/admin
        nameof(TrackingController),        // read-only serial/batch pickers used inside sales and stock screens
        nameof(SearchController),          // gated per result type inside GlobalSearchService
        nameof(MetaController),
    };

    [Fact]
    public void EveryDataChangingEndpoint_IsBehindAPermission()
    {
        var uncovered = new List<string>();
        foreach (var controller in ApiControllers().Where(c => !OpenByDesign.Contains(c.Name)))
        {
            var classCovered = NavPolicyNames(controller).Any();
            foreach (var action in controller.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)
                         .Where(m => m.GetCustomAttributes().OfType<Microsoft.AspNetCore.Mvc.Routing.HttpMethodAttribute>().Any()))
            {
                if (IsReadOnly(action)) continue;
                if (action.GetCustomAttributes<AllowAnonymousAttribute>().Any()) continue;
                if (!classCovered && !NavPolicyNames(action).Any()) uncovered.Add($"{controller.Name}.{action.Name}");
            }
        }

        Assert.True(uncovered.Count == 0, "Data-changing endpoints with no Nav permission: " + string.Join(", ", uncovered));
    }

    [Fact]
    public void EveryControllerAboutSensitiveData_IsGatedAsAWhole()
    {
        // HR (salaries, bank accounts, loans, payslips) and the audit trail used to be open to every signed-in person.
        foreach (var name in new[]
                 {
                     "AttendanceBatchesController", "LeaveRequestsController", "PayrollRunsController", "PayslipsController",
                     "HrReportsController", "EmployeesController", "SalaryComponentsController", "TaxSlabsController",
                     "PayrollStatutorySettingsController", "AuditLogsController",
                 })
        {
            var type = typeof(ApiControllerBase).Assembly.GetTypes().Single(t => t.Name == name);
            Assert.True(NavPolicyNames(type).Any(), $"{name} has no class-level Nav permission.");
        }
    }

    [Fact]
    public void PayData_NeedsThePayrollPermission_OnTopOfEmployees()
    {
        var employees = typeof(ApiControllerBase).Assembly.GetTypes().Single(t => t.Name == "EmployeesController");
        foreach (var action in new[] { "ListBankDetails", "GetSalaryStructureHistory", "ListLoans", "GetLoan", "CreateLoan", "CreateSalaryStructure", "ReplaceBankDetails" })
        {
            var method = employees.GetMethod(action)!;
            Assert.Contains(NavPolicyNames(method), p => p.StartsWith(NavPolicies.Prefix + "hrm.payroll", StringComparison.Ordinal));
        }

        var reports = typeof(ApiControllerBase).Assembly.GetTypes().Single(t => t.Name == "HrReportsController");
        foreach (var action in new[] { "PayrollRegister", "SalaryHistory" })
            Assert.Contains(NavPolicyNames(reports.GetMethod(action)!), p => p == NavPolicies.Prefix + "hrm.payroll");
    }

    [Fact]
    public void EveryNavCodeTheControllersName_ExistsInTheSeededCatalogue()
    {
        // The old Nav:vendors policy named a code that no longer existed, so only administrators got through.
        using var db = CreateContext();
        var seeded = Seed<Permission>(db)
            .Select(d => ((string)d[nameof(Permission.Code)]!).Substring("NAV:".Length))
            .ToHashSet(StringComparer.Ordinal);

        var missing = new SortedSet<string>();
        foreach (var controller in ApiControllers())
        {
            var names = NavPolicyNames(controller).Concat(
                controller.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly).SelectMany(NavPolicyNames));
            foreach (var name in names)
            {
                var rest = name[NavPolicies.Prefix.Length..];
                var sep = rest.LastIndexOf(NavPolicies.ActionSeparator, StringComparison.Ordinal);
                var code = sep >= 0 && Enum.TryParse<RolePermissionAction>(rest[(sep + 1)..], out _) ? rest[..sep] : rest;
                // A module code is satisfied by the module itself or any screen inside it (HasAccessAsync does the same).
                if (!seeded.Contains(code) && !seeded.Any(s => s.StartsWith(code + ".", StringComparison.Ordinal))) missing.Add($"{controller.Name}: {code}");
            }
        }

        Assert.True(missing.Count == 0, "Controllers name permissions that are not seeded: " + string.Join("; ", missing));
    }

    [Fact]
    public void SeededCatalogue_HasNoDuplicateCodes_AndEverySubItemHasAPermission()
    {
        using var db = CreateContext();
        var permissions = Seed<Permission>(db).ToList();
        var codes = permissions.Select(p => (string)p[nameof(Permission.Code)]!).ToList();
        Assert.Equal(codes.Count, codes.Distinct().Count());

        var subItems = Seed<SubNavItem>(db);
        var granted = permissions.Where(p => p[nameof(Permission.SubNavItemId)] is not null).Select(p => (int)p[nameof(Permission.SubNavItemId)]!).ToHashSet();
        foreach (var sub in subItems)
            Assert.True(granted.Contains((int)sub[nameof(SubNavItem.SubNavItemId)]!), $"No permission row for sub item {sub[nameof(SubNavItem.Code)]}.");
    }

    [Theory]
    [InlineData("hrm")]
    [InlineData("hrm.employees")]
    [InlineData("hrm.payroll")]
    [InlineData("sales-returns")]
    [InlineData("settings.audit-logs")]
    public void NewPermissions_AreSeeded(string code)
    {
        using var db = CreateContext();
        var codes = Seed<Permission>(db).Select(d => (string)d[nameof(Permission.Code)]!);
        Assert.Contains("NAV:" + code, codes);
    }

    // ---------------------------------------------------------------- the policies actually decide

    private sealed class FakeUser(int? roleId, bool isAdmin = false, int? branchId = null, bool branching = true) : ICurrentUser
    {
        public int AuditUserId => 10;
        public int? RoleId => roleId;
        public string? RoleCode => null;
        public bool IsAdmin => isAdmin;
        public string UserId => "10";
        public bool IsAuthenticated => true;
        public int? BranchId => branchId;
        public bool BranchingEnabled => branching;
    }

    private static async Task<(ErpDbContext Db, NavPermissionService Nav)> RolesAsync()
    {
        var db = CreateContext();
        db.Roles.AddRange(
            new Role { RoleId = 1, Code = "Hr", Name = "HR officer", CreatedAt = DateTime.UtcNow },
            new Role { RoleId = 2, Code = "Clerk", Name = "Clerk", CreatedAt = DateTime.UtcNow });
        db.NavItems.Add(new NavItem { NavItemId = 100, Code = "hrm", Label = "HR" });
        db.SubNavItems.AddRange(
            new SubNavItem { SubNavItemId = 101, NavItemId = 100, Code = "hrm.employees", Label = "Employees" },
            new SubNavItem { SubNavItemId = 102, NavItemId = 100, Code = "hrm.payroll", Label = "Payroll" });
        db.Permissions.AddRange(
            new Permission { PermissionId = 200, Code = "NAV:hrm.employees", SubNavItemId = 101 },
            new Permission { PermissionId = 201, Code = "NAV:hrm.payroll", SubNavItemId = 102 });
        db.RolePermissions.Add(new RolePermission { RoleId = 1, PermissionId = 200, Actions = RolePermissionAction.View | RolePermissionAction.Edit });
        await db.SaveChangesAsync();
        return (db, new NavPermissionService(new Repository<Role>(db), new Repository<RolePermission>(db), new MemoryCache(new MemoryCacheOptions())));
    }

    private static async Task<bool> PassesAsync(NavPermissionService nav, ICurrentUser user, string policyName)
    {
        var provider = new NavPolicyProvider(Microsoft.Extensions.Options.Options.Create(new AuthorizationOptions()));
        var policy = (await provider.GetPolicyAsync(policyName))!;
        var requirement = policy.Requirements.OfType<NavRequirement>().Single();
        var context = new AuthorizationHandlerContext(new[] { requirement }, new ClaimsPrincipal(new ClaimsIdentity("test")), null);
        await new NavAuthorizationHandler(user, nav).HandleAsync(context);
        return context.HasSucceeded;
    }

    [Fact]
    public async Task HrOfficer_ReachesEmployees_ButNotPayData_AndAnAdministratorReachesAll()
    {
        var (db, nav) = await RolesAsync();
        await using var _ = db;
        var hr = new FakeUser(roleId: 1);

        Assert.True(await PassesAsync(nav, hr, "Nav:hrm"));                    // the module, via a screen inside it
        Assert.True(await PassesAsync(nav, hr, "Nav:hrm.employees"));
        Assert.True(await PassesAsync(nav, hr, "Nav:hrm.employees:Edit"));
        Assert.False(await PassesAsync(nav, hr, "Nav:hrm.employees:Delete"));  // not granted
        Assert.False(await PassesAsync(nav, hr, "Nav:hrm.payroll"));           // salaries, loans, bank accounts
        Assert.False(await PassesAsync(nav, hr, "Nav:settings.audit-logs"));

        Assert.False(await PassesAsync(nav, new FakeUser(roleId: 2), "Nav:hrm"));
        Assert.False(await PassesAsync(nav, new FakeUser(roleId: null), "Nav:hrm"));

        Assert.True(await PassesAsync(nav, new FakeUser(roleId: 2, isAdmin: true), "Nav:hrm.payroll:Approve"));
    }

    // ---------------------------------------------------------------- global search follows the role

    [Fact]
    public async Task Search_OnlyReturnsKindsTheRoleMayOpen()
    {
        var (db, nav) = await RolesAsync();
        await using var _ = db;
        db.Employees.Add(new Employee { EmployeeId = 1, EmployeeCode = "E-1", FullName = "Alice Perera", BranchId = Branch1 });
        await db.SaveChangesAsync();

        GlobalSearchService Search(ICurrentUser u) => new(
            new Repository<Item>(db), new Repository<PurchaseOrder>(db), new Repository<SalesSlip>(db), new Repository<Employee>(db), u, nav);

        var hr = await Search(new FakeUser(roleId: 1)).SearchAsync("Alice");
        Assert.Contains(hr, r => r.Type == GlobalSearchResultType.Employee);

        var clerk = await Search(new FakeUser(roleId: 2)).SearchAsync("Alice");
        Assert.DoesNotContain(clerk, r => r.Type == GlobalSearchResultType.Employee);

        var admin = await Search(new FakeUser(roleId: 2, isAdmin: true)).SearchAsync("Alice");
        Assert.Contains(admin, r => r.Type == GlobalSearchResultType.Employee);
    }

    // ---------------------------------------------------------------- CSRF on every cookie-authenticated mutation

    private static (CsrfProtectionFilter Filter, ActionExecutingContext Context) CsrfCall(
        string method, string? cookie = "token", string? header = null, bool sessionCookie = true,
        bool bearer = false, bool anonymousEndpoint = false, bool hasCsrfAttribute = false)
    {
        var http = new DefaultHttpContext();
        http.Request.Method = method;
        var cookies = new List<string>();
        if (sessionCookie) cookies.Add("erp_at=jwt");
        if (cookie is not null) cookies.Add($"XSRF-TOKEN={cookie}");
        if (cookies.Count > 0) http.Request.Headers.Cookie = string.Join("; ", cookies);
        if (header is not null) http.Request.Headers["X-XSRF-TOKEN"] = header;
        if (bearer) http.Request.Headers.Authorization = "Bearer abc";

        var metadata = new List<object>();
        if (anonymousEndpoint) metadata.Add(new AllowAnonymousAttribute());
        if (hasCsrfAttribute) metadata.Add(new ValidateCsrfAttribute());
        http.SetEndpoint(new Endpoint(null, new EndpointMetadataCollection(metadata), "test"));

        var actionContext = new ActionContext(http, new RouteData(), new ActionDescriptor());
        var context = new ActionExecutingContext(actionContext, new List<IFilterMetadata>(), new Dictionary<string, object?>(), new object());
        return (new CsrfProtectionFilter(), context);
    }

    private static async Task<bool> RunAsync(CsrfProtectionFilter filter, ActionExecutingContext context)
    {
        var ran = false;
        await filter.OnActionExecutionAsync(context, () =>
        {
            ran = true;
            return Task.FromResult(new ActionExecutedContext(context, context.Filters, context.Controller));
        });
        return ran;
    }

    [Theory]
    [InlineData("POST")]
    [InlineData("PUT")]
    [InlineData("PATCH")]
    [InlineData("DELETE")]
    public async Task CookieRequest_WithoutTheCsrfHeader_IsRefused(string method)
    {
        var (filter, context) = CsrfCall(method, cookie: "token", header: null);
        var ex = await Assert.ThrowsAsync<DomainException>(() => RunAsync(filter, context));
        Assert.Equal(ErrorCodes.CsrfTokenMismatch, ex.Code);
        Assert.Equal(403, ex.StatusCode);
    }

    [Fact]
    public async Task CookieRequest_WithAWrongOrMissingCsrfCookie_IsRefused()
    {
        var (f1, c1) = CsrfCall("POST", cookie: "token", header: "other");
        await Assert.ThrowsAsync<DomainException>(() => RunAsync(f1, c1));

        var (f2, c2) = CsrfCall("POST", cookie: null, header: "token");
        await Assert.ThrowsAsync<DomainException>(() => RunAsync(f2, c2));
    }

    [Fact]
    public async Task CookieRequest_WithMatchingCsrfHeader_Runs()
    {
        var (filter, context) = CsrfCall("DELETE", cookie: "token", header: "token");
        Assert.True(await RunAsync(filter, context));
    }

    [Theory]
    [InlineData("GET")]
    [InlineData("HEAD")]
    [InlineData("OPTIONS")]
    public async Task SafeMethods_AreNotChecked(string method)
    {
        var (filter, context) = CsrfCall(method, cookie: null);
        Assert.True(await RunAsync(filter, context));
    }

    [Fact]
    public async Task BearerCallers_AnonymousEndpoints_AndRequestsWithoutASessionCookie_AreNotChecked()
    {
        var (f1, c1) = CsrfCall("POST", cookie: null, bearer: true);
        Assert.True(await RunAsync(f1, c1));

        var (f2, c2) = CsrfCall("POST", cookie: null, anonymousEndpoint: true);
        Assert.True(await RunAsync(f2, c2));

        var (f3, c3) = CsrfCall("POST", cookie: null, sessionCookie: false);
        Assert.True(await RunAsync(f3, c3));
    }

    [Fact]
    public async Task ActionsThatCarryTheirOwnCsrfAttribute_AreNotCheckedTwice()
    {
        var (filter, context) = CsrfCall("POST", cookie: null, hasCsrfAttribute: true);
        Assert.True(await RunAsync(filter, context)); // the attribute itself enforces it
    }

    [Fact]
    public void TheCsrfFilter_IsRegisteredGlobally()
    {
        var program = File.ReadAllText(Path.Combine(FindBackendRoot(), "ERPCore", "Program.cs"));
        Assert.Contains("Filters.Add<ERPCore.Infra.Auth.CsrfProtectionFilter>()", program);
    }

    private static string FindBackendRoot()
    {
        var dir = new DirectoryInfo(AppContext.BaseDirectory);
        while (dir is not null && !Directory.Exists(Path.Combine(dir.FullName, "ERPCore"))) dir = dir.Parent;
        return dir?.FullName ?? throw new DirectoryNotFoundException("Backend root not found.");
    }

    // ---------------------------------------------------------------- a branch-less person can't read every branch

    [Fact]
    public void BranchContext_AdministratorsAreNeverScoped()
    {
        var ctx = new CurrentBranchContext(new FakeUser(roleId: 1, isAdmin: true, branchId: 5));
        Assert.False(ctx.IsActive);
        Assert.Null(ctx.BranchId);
    }

    [Fact]
    public void BranchContext_AnEmployeeIsScopedToTheirOwnBranch()
    {
        var ctx = new CurrentBranchContext(new FakeUser(roleId: 1, branchId: 5));
        Assert.True(ctx.IsActive);
        Assert.Equal(5, ctx.BranchId);
    }

    [Fact]
    public void BranchContext_APersonWithNoBranch_InABranchingDeployment_SeesNoBranchAtAll()
    {
        var ctx = new CurrentBranchContext(new FakeUser(roleId: 1, branchId: null, branching: true));
        Assert.True(ctx.IsActive);
        Assert.Equal(CurrentBranchContext.NoBranchId, ctx.BranchId);
    }

    [Fact]
    public void BranchContext_APersonWithNoBranch_WhenBranchingIsOff_IsNotScoped()
    {
        var ctx = new CurrentBranchContext(new FakeUser(roleId: 1, branchId: null, branching: false));
        Assert.False(ctx.IsActive);
        Assert.Null(ctx.BranchId);
    }

    [Fact]
    public async Task QueryFilters_HideEveryWarehouse_FromABranchlessNonAdmin_ButNotFromAnAdminOrWhenBranchingIsOff()
    {
        var options = new DbContextOptionsBuilder<ErpDbContext>()
            .UseInMemoryDatabase(Guid.NewGuid().ToString("N")).Options;

        async Task<int> CountFor(ICurrentUser user, bool seed)
        {
            await using var db = new ErpDbContext(options, user, new CurrentBranchContext(user));
            if (seed)
            {
                db.Warehouses.AddRange(
                    new Warehouse { WarehouseId = 1, Code = "W1", Name = "One", BranchId = 1 },
                    new Warehouse { WarehouseId = 2, Code = "W2", Name = "Two", BranchId = 2 });
                await db.SaveChangesAsync();
            }
            return db.Warehouses.Count();
        }

        Assert.Equal(2, await CountFor(new FakeUser(1, isAdmin: true), seed: true));
        Assert.Equal(1, await CountFor(new FakeUser(1, branchId: 2), seed: false));
        Assert.Equal(0, await CountFor(new FakeUser(1, branchId: null, branching: true), seed: false));
        Assert.Equal(2, await CountFor(new FakeUser(1, branchId: null, branching: false), seed: false));
    }
}