using System.Net.Http.Json;

namespace HSchool.AppHost.Tests;

[Collection(AppHostCollection.Name)]
public class StaffingApiTests(AppHostFixture fixture)
{
    private static readonly DateTime Start = new(2012, 3, 31, 6, 0, 0, DateTimeKind.Utc);

    [Fact]
    public async Task GetStaffing_UnknownSchool_IsNotFound()
    {
        using var client = fixture.App.CreateHttpClient("server");

        using var response = await client.GetAsync("/api/schools/999999/staffing", TestContext.Current.CancellationToken);
        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
        Assert.Equal("unknown-school", await ProblemCodeAsync(response));
    }

    [Fact]
    public async Task GetStaffing_EmptySchool_HasPoolAndNoPayroll()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат пустой", Start);

        var staffing = await GetStaffingAsync(client, school.Id);

        Assert.Equal(100_000f, staffing.Allocated);
        Assert.Equal(0f, staffing.Payroll);
        Assert.Equal(100_000f, staffing.Remaining);
        Assert.Equal(12, staffing.Applicants.Count);
        Assert.Empty(staffing.Staff);
        Assert.Contains(staffing.Uncovered, subject => subject.DefName == "Mathematics");
        Assert.Contains(staffing.Uncovered, subject => subject.DefName == "PrimarySchool");
        Assert.NotEmpty(staffing.Positions);
        Assert.Contains(staffing.Positions, position => position.DefName == "Teacher");
        Assert.Contains(staffing.Subjects, subject => subject.DefName == "Mathematics");
        Assert.All(staffing.Applicants, applicant => Assert.NotEmpty(applicant.Skills));
    }

    [Fact]
    public async Task Card_OpensAGeneratedApplicant()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат карточка пула", Start);
        var staffing = await GetStaffingAsync(client, school.Id);
        var generated = staffing.Applicants.First(applicant => !applicant.IsParent);

        var card = await client.GetFromJsonAsync<PersonCardResponse>(
            $"/api/schools/{school.Id}/people/{Uri.EscapeDataString(generated.Id)}?lang=ru",
            TestContext.Current.CancellationToken);
        Assert.NotNull(card);
        Assert.Equal(generated.Id, card.Id);
        Assert.NotEmpty(card.Skills);
    }

    [Fact]
    public async Task Hire_ParentKeepsBothRolesOnTheCard()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат родитель", Start);
        var before = await GetStaffingAsync(client, school.Id);
        var parent = before.Applicants.First(applicant => applicant.IsParent);

        await HireAsync(client, school.Id, parent.Id, "Teacher");

        var card = await client.GetFromJsonAsync<PersonCardResponse>(
            $"/api/schools/{school.Id}/people/{Uri.EscapeDataString(parent.Id)}?lang=ru",
            TestContext.Current.CancellationToken);
        Assert.NotNull(card);
        Assert.Contains("parent", card.Roles);
        Assert.Contains("staff", card.Roles);
    }

    [Fact]
    public async Task Hire_AddsStaff_RemovesApplicant_AndRejectsASecondHireOfTheSamePerson()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат наём", Start);
        var before = await GetStaffingAsync(client, school.Id);
        var applicant = before.Applicants[0];

        var after = await HireAsync(client, school.Id, applicant.Id, "Teacher");

        Assert.Contains(after.Staff, member => member.Id == applicant.Id && member.Position == "Teacher");
        Assert.DoesNotContain(after.Applicants, candidate => candidate.Id == applicant.Id);
        Assert.True(after.Payroll > 0f);
        Assert.True(after.Payroll <= after.Allocated);

        using var again = await client.PostAsJsonAsync(
            $"/api/schools/{school.Id}/staff/hire",
            new { personId = applicant.Id, position = "Teacher" },
            TestContext.Current.CancellationToken);
        Assert.Equal(HttpStatusCode.Conflict, again.StatusCode);
        Assert.Equal("already-hired", await ProblemCodeAsync(again));

        var people = await client.GetFromJsonAsync<PeopleListResponse>(
            $"/api/schools/{school.Id}/people?role=staff&pageSize=10",
            TestContext.Current.CancellationToken);
        Assert.NotNull(people);
        Assert.Contains(people.People, person => person.Id == applicant.Id);
    }

    [Fact]
    public async Task Hire_UnknownApplicant_IsNotFound()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат неизвестный", Start);

        using var response = await client.PostAsJsonAsync(
            $"/api/schools/{school.Id}/staff/hire",
            new { personId = "nobody", position = "Teacher" },
            TestContext.Current.CancellationToken);
        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
        Assert.Equal("unknown-applicant", await ProblemCodeAsync(response));
    }

    [Fact]
    public async Task Hire_IdlePool_FitsUnderTheCap()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат предел", Start);

        var staffing = await GetStaffingAsync(client, school.Id);
        while (staffing.Applicants.Count > 0)
        {
            var applicant = staffing.Applicants[0];
            using var response = await client.PostAsJsonAsync(
                $"/api/schools/{school.Id}/staff/hire",
                new { personId = applicant.Id, position = "Teacher" },
                TestContext.Current.CancellationToken);
            response.EnsureSuccessStatusCode();
            staffing = await response.Content.ReadFromJsonAsync<StaffingResponse>(TestContext.Current.CancellationToken);
            Assert.NotNull(staffing);
        }

        Assert.Equal(100_000f, staffing.Allocated);
        Assert.True(staffing.Payroll > 0f);
        Assert.True(staffing.Payroll <= staffing.Allocated);
        Assert.Equal(12, staffing.Staff.Count);
    }

    [Fact]
    public async Task AssignAndUnassign_HonourTheCap_AndReloadKeepsAssignments()
    {
        using var client = fixture.App.CreateHttpClient("server");
        await SchoolApiTests.ResetAsync(client);
        var school = await SchoolApiTests.CreateAsync(client, "Штат предметы", Start);
        var before = await GetStaffingAsync(client, school.Id);
        var hired = await HireAsync(client, school.Id, before.Applicants[0].Id, "Teacher");
        var teacher = hired.Staff.Single();

        var assigned = await AssignAsync(client, school.Id, teacher.Id, "Mathematics");
        // The first subject already costs: 35 curriculum hours is well past one full rate.
        Assert.True(assigned.Payroll > hired.Payroll);

        assigned = await AssignAsync(client, school.Id, teacher.Id, "RussianLanguage");
        Assert.True(assigned.Payroll > hired.Payroll);
        Assert.Equal(2, assigned.Staff.Single().Subjects.Count);

        using var over = await client.PostAsJsonAsync(
            $"/api/schools/{school.Id}/staff/{Uri.EscapeDataString(teacher.Id)}/subjects",
            new { subject = "Literature" },
            TestContext.Current.CancellationToken);
        // Cheap asks may still fit; only the numbers matter when the cap actually bites.
        if (over.StatusCode == HttpStatusCode.Conflict)
        {
            var problem = await over.Content.ReadFromJsonAsync<ProblemResponse>(TestContext.Current.CancellationToken);
            Assert.Equal("payroll-exceeded", problem?.Code);
            Assert.True(problem?.Attempted > problem?.Allocated);
            Assert.Equal(assigned.Payroll, problem?.Payroll);
        }
        else
        {
            over.EnsureSuccessStatusCode();
            assigned = await over.Content.ReadFromJsonAsync<StaffingResponse>(TestContext.Current.CancellationToken);
            Assert.NotNull(assigned);
        }

        var payrollWithSubjects = assigned.Payroll;
        using var unassign = await client.DeleteAsync(
            $"/api/schools/{school.Id}/staff/{Uri.EscapeDataString(teacher.Id)}/subjects/RussianLanguage",
            TestContext.Current.CancellationToken);
        unassign.EnsureSuccessStatusCode();
        var afterDrop = await unassign.Content.ReadFromJsonAsync<StaffingResponse>(TestContext.Current.CancellationToken);
        Assert.NotNull(afterDrop);
        Assert.True(afterDrop.Payroll < payrollWithSubjects);

        using var reload = await client.PostAsync("/api/dev/reload-schools", content: null, TestContext.Current.CancellationToken);
        reload.EnsureSuccessStatusCode();

        var restored = await GetStaffingAsync(client, school.Id);
        Assert.Equal(afterDrop.Payroll, restored.Payroll);
        Assert.Equal(teacher.Id, restored.Staff.Single().Id);
        Assert.Equal(
            afterDrop.Staff.Single().Subjects.Select(subject => subject.DefName),
            restored.Staff.Single().Subjects.Select(subject => subject.DefName));
    }

    private static async Task<StaffingResponse> GetStaffingAsync(HttpClient client, int schoolId)
    {
        var staffing = await client.GetFromJsonAsync<StaffingResponse>(
            $"/api/schools/{schoolId}/staffing?lang=ru",
            TestContext.Current.CancellationToken);
        Assert.NotNull(staffing);
        return staffing;
    }

    private static async Task<StaffingResponse> HireAsync(HttpClient client, int schoolId, string personId, string position)
    {
        using var response = await client.PostAsJsonAsync(
            $"/api/schools/{schoolId}/staff/hire",
            new { personId, position },
            TestContext.Current.CancellationToken);
        response.EnsureSuccessStatusCode();
        var staffing = await response.Content.ReadFromJsonAsync<StaffingResponse>(TestContext.Current.CancellationToken);
        Assert.NotNull(staffing);
        return staffing;
    }

    private static async Task<StaffingResponse> AssignAsync(HttpClient client, int schoolId, string personId, string subject)
    {
        using var response = await client.PostAsJsonAsync(
            $"/api/schools/{schoolId}/staff/{Uri.EscapeDataString(personId)}/subjects",
            new { subject },
            TestContext.Current.CancellationToken);
        response.EnsureSuccessStatusCode();
        var staffing = await response.Content.ReadFromJsonAsync<StaffingResponse>(TestContext.Current.CancellationToken);
        Assert.NotNull(staffing);
        return staffing;
    }

    private static async Task<string?> ProblemCodeAsync(HttpResponseMessage response)
    {
        var problem = await response.Content.ReadFromJsonAsync<ProblemResponse>(TestContext.Current.CancellationToken);
        return problem?.Code;
    }

    private sealed record ProblemResponse(string? Code, float? Allocated, float? Payroll, float? Remaining, float? Attempted);

    private sealed record StaffingResponse(
        float Allocated,
        float Payroll,
        float Remaining,
        IReadOnlyList<UncoveredSubjectResponse> Uncovered,
        IReadOnlyList<ApplicantResponse> Applicants,
        IReadOnlyList<StaffMemberResponse> Staff,
        IReadOnlyList<DefLabelResponse> Positions,
        IReadOnlyList<UncoveredSubjectResponse> Subjects);

    private sealed record UncoveredSubjectResponse(string DefName, string Label, int GradeMin, int GradeMax, int HoursPerWeek);

    private sealed record ApplicantResponse(
        string Id,
        string FullName,
        bool Female,
        int Age,
        bool IsParent,
        float HourlyWageAsk,
        float MonthlyBase,
        IReadOnlyList<LabeledStatResponse> Skills);

    private sealed record LabeledStatResponse(string Id, string Label, string Value);

    private sealed record StaffMemberResponse(
        string Id,
        string FullName,
        bool Female,
        int Age,
        bool IsParent,
        string Position,
        string PositionLabel,
        float HourlyWageAsk,
        float MonthlyPay,
        IReadOnlyList<DefLabelResponse> Subjects);

    private sealed record DefLabelResponse(string DefName, string Label);

    private sealed record PersonCardResponse(string Id, IReadOnlyList<string> Roles, IReadOnlyList<LabeledStatResponse> Skills);

    private sealed record PeopleListResponse(
        int Total,
        int Page,
        int PageSize,
        IReadOnlyList<PersonListItemResponse> People,
        object Filters);

    private sealed record PersonListItemResponse(
        string Id,
        string FullName,
        string Surname,
        string Given,
        string Patronymic,
        bool Female,
        int Age,
        IReadOnlyList<string> Roles,
        int? ClassYear,
        string? ClassLetter,
        string? Position,
        string? PositionLabel);
}