using System.Net;
using System.Net.Http.Json;
using System.Text.Json;
using System.Text.Json.Serialization;
using Tnsu.ApprovalRoute.Domain.Enums;

namespace Tnsu.ApprovalRoute.Infrastructure.TnsuPortal;

public sealed class HttpTnsuPortalClient(
    HttpClient httpClient,
    TnsuPortalAuthorizer authorizer) : ITnsuPortalClient
{
    private static readonly JsonSerializerOptions JsonOptions = new() { PropertyNameCaseInsensitive = true };

    public async Task<IReadOnlyList<EmployeeDirectoryInfo>> GetEmployeeByEmailAsync(string email, CancellationToken cancellationToken)
    {
        var employees = await GetAsync<List<EmployeeResponse>>(
            $"/Employee/ByEmail?email={Uri.EscapeDataString(email)}", cancellationToken);
        if (employees is null)
            return [];

        return employees
            .Select(e => new EmployeeDirectoryInfo(e.CompanyId ?? Guid.Empty, e.DepartmentId, e.Company ?? string.Empty, e.Position, e.Id))
            .ToList();
    }

    public async Task<EmployeeLookupResult> GetEmployeeByPositionAsync(string position, string company, CancellationToken cancellationToken)
    {
        var employee = await GetAsync<EmployeeResponse>(
            $"/Employee/ByPosition?position={Uri.EscapeDataString(position)}&company={Uri.EscapeDataString(company)}", cancellationToken);

        return new EmployeeLookupResult(employee is not null, employee?.Email, employee?.Fio);
    }

    public async Task<IReadOnlyList<EmployeeContactInfo>> GetAllEmployeesAsync(CancellationToken cancellationToken)
    {
        var employees = await GetAsync<List<EmployeeResponse>>("/Employee/All", cancellationToken);
        if (employees is null)
            return [];

        return employees
            .Where(e => !string.IsNullOrWhiteSpace(e.Fio))
            .Select(e => new EmployeeContactInfo(e.Id, e.Fio!, e.Email, e.Company ?? string.Empty, e.Position))
            .ToList();
    }

    // /Dictionary/* отдаёт «голый» массив с ключами в PascalCase (Id/Name) —
    // PropertyNameCaseInsensitive в JsonOptions это покрывает.
    public async Task<IReadOnlyList<CompanyInfo>> GetCompaniesAsync(CancellationToken cancellationToken)
    {
        var companies = await GetAsync<List<DictionaryItemResponse>>("/Dictionary/Companies", cancellationToken);
        return (companies ?? [])
            .Where(c => c.Id is not null && !string.IsNullOrWhiteSpace(c.Name))
            .Select(c => new CompanyInfo(c.Id!.Value, c.Name!))
            .ToList();
    }

    public async Task<IReadOnlyList<DepartmentInfo>> GetDepartmentsAsync(CancellationToken cancellationToken)
    {
        var departments = await GetAsync<List<DictionaryItemResponse>>("/Dictionary/Departments", cancellationToken);
        return (departments ?? [])
            .Where(d => d.Id is not null && !string.IsNullOrWhiteSpace(d.Name))
            .Select(d => new DepartmentInfo(d.Id!.Value, d.Name!))
            .ToList();
    }

    public async Task<string?> GetManagerAsync(string email, string managerType, CancellationToken cancellationToken)
    {
        var manager = await GetAsync<ManagerResponse>(
            $"/Employee/Manager?email={Uri.EscapeDataString(email)}&managerType={Uri.EscapeDataString(managerType)}", cancellationToken);

        return manager?.ManagerEmail;
    }

    public async Task<IReadOnlyList<EmployeeFullBaseInfo>> GetFullBaseAsync(CancellationToken cancellationToken)
    {
        var employees = await GetAsync<List<FullBaseResponse>>("/Employee/FullBase", cancellationToken);
        if (employees is null)
            return [];

        return employees
            .Where(e => !string.IsNullOrWhiteSpace(e.Fio))
            .Select(e => new EmployeeFullBaseInfo(e.Id, e.Fio!, e.Company ?? string.Empty, e.DismissalDate))
            .ToList();
    }

    public async Task<IReadOnlyList<ProjectExecutorInfo>> GetProjectExecutorsAsync(Guid projectId, CancellationToken cancellationToken)
    {
        var project = await GetAsync<ProjectResponse>($"/Project/{projectId}", cancellationToken);
        if (project is null)
            return [];

        var executors = new List<ProjectExecutorInfo>();
        AddIfPresent(executors, ProjectRole.ProjectManager, project.ProjectManager);
        AddIfPresent(executors, ProjectRole.Planner, project.Planner);
        AddIfPresent(executors, ProjectRole.ManagerHSE, project.ManagerHSE);
        AddIfPresent(executors, ProjectRole.Security, project.Security);
        AddIfPresent(executors, ProjectRole.Keeper, project.Keeper);

        return executors;
    }

    // Ответ — {"managerEmail": "..."} (та же форма, что у /Employee/Manager),
    // а НЕ форма сотрудника (EmployeeResponse) — проверено живым вызовом
    // (GET /Employee/DepartmentHead?departmentId=... на отделе "АУП"/"ТОО
    // Монтажник-Т" вернул именно managerEmail). 404 с телом {"error": "..."}
    // на отделах без руководителя уже отфильтровывается общим GetAsync<T>.
    public async Task<string?> GetDepartmentHeadEmailAsync(Guid departmentId, CancellationToken cancellationToken)
    {
        var manager = await GetAsync<ManagerResponse>(
            $"/Employee/DepartmentHead?departmentId={Uri.EscapeDataString(departmentId.ToString())}", cancellationToken);

        return manager?.ManagerEmail;
    }

    private async Task<T?> GetAsync<T>(string requestUri, CancellationToken cancellationToken) where T : class
    {
        using var request = new HttpRequestMessage(HttpMethod.Get, requestUri);
        await authorizer.AuthorizeAsync(request, cancellationToken);

        using var response = await httpClient.SendAsync(request, cancellationToken);
        if (response.StatusCode == HttpStatusCode.NotFound)
            return null;
        response.EnsureSuccessStatusCode();

        return await response.Content.ReadFromJsonAsync<T>(JsonOptions, cancellationToken);
    }

    private static void AddIfPresent(List<ProjectExecutorInfo> executors, ProjectRole role, string? email)
    {
        if (!string.IsNullOrWhiteSpace(email))
            executors.Add(new ProjectExecutorInfo(role, email));
    }

    private sealed record EmployeeResponse(
        [property: JsonPropertyName("email")] string? Email,
        [property: JsonPropertyName("company")] string? Company,
        [property: JsonPropertyName("companyId")] Guid? CompanyId,
        [property: JsonPropertyName("departmentId")] Guid? DepartmentId,
        [property: JsonPropertyName("position")] string? Position,
        [property: JsonPropertyName("fio")] string? Fio,
        [property: JsonPropertyName("id")] Guid? Id = null);

    private sealed record DictionaryItemResponse(
        [property: JsonPropertyName("id")] Guid? Id,
        [property: JsonPropertyName("name")] string? Name);

    private sealed record ManagerResponse(
        [property: JsonPropertyName("managerEmail")] string? ManagerEmail);

    private sealed record FullBaseResponse(
        [property: JsonPropertyName("id")] Guid? Id,
        [property: JsonPropertyName("fio")] string? Fio,
        [property: JsonPropertyName("company")] string? Company,
        [property: JsonPropertyName("dismissalDate")] DateTimeOffset? DismissalDate);

    private sealed record ProjectResponse(
        [property: JsonPropertyName("projectManager")] string? ProjectManager,
        [property: JsonPropertyName("planner")] string? Planner,
        [property: JsonPropertyName("managerHSE")] string? ManagerHSE,
        [property: JsonPropertyName("security")] string? Security,
        [property: JsonPropertyName("keeper")] string? Keeper);
}