using Microsoft.AspNetCore.Http.HttpResults;
using MinAttest.Contracts.Attests;
using MinAttest.Contracts.Employers;
using MediatR;
using MinAttest.Application.Features.Employers.Commands;
using MinAttest.Application.Features.Employers.Queries;
using MinAttest.Application.Features.Attests.Commands;
using MinAttest.Application.Features.Attests.Queries;

namespace MinAttest.Api.Features.Employer;

public static class Employers
{
    public static RouteGroupBuilder MapEmployer(this RouteGroupBuilder group)
    {
        var employers = group.MapGroup("/employers");

        employers.MapPost("/", UpsertEmployer)
                 .WithName("UpsertEmployer")
                 .WithOpenApi();

        employers.MapGet("/", ListEmployers)
                 .WithName("ListEmployers")
                 .WithOpenApi();

        employers.MapGet("/{id:guid}", GetEmployer)
                 .WithName("GetEmployer")
                 .WithOpenApi();

        employers.MapGet("/{employerId:guid}/users", ListEmployerUsers)
                 .WithName("ListEmployerUsers")
                 .WithOpenApi();

        employers.MapGet("/{employerId:guid}/users/{userId:guid}", GetEmployerUser)
                 .WithName("GetEmployerUser")
                 .WithOpenApi();

        employers.MapPost("/{employerId:guid}/users", UpsertEmployerUser)
                 .WithName("UpsertEmployerUser")
                 .WithOpenApi();

        employers.MapDelete("/{employerId:guid}/users/{userId:guid}", DeleteEmployerUser)
                 .WithName("DeleteEmployerUser")
                 .WithOpenApi();

        employers.MapPost("/{id:guid}/attests", IssueAttestForEmployer)
                 .WithName("IssueAttestForEmployer")
                 .WithOpenApi();

        employers.MapGet("/{id:guid}/attests", ListAttestsForEmployer)
                 .WithName("ListAttestsForEmployer")
                 .WithOpenApi();

        employers.MapGet("/{id:guid}/attests/{attestId:guid}/download", DownloadAttestForEmployer)
                 .WithName("DownloadAttestForEmployer")
                 .WithOpenApi();        

        return group;
    }

    private static async Task<IResult> IssueAttestForEmployer(Guid id, EmployerAttestUploadRequest req, IMediator mediator, CancellationToken ct)
    {
        var createdId = await mediator.Send(new EmployerIssueAttestCommand(id, req), ct);
        if (createdId is null) return Results.NotFound();
        return Results.Created($"/api/v1/employers/{id}/attests/{createdId}", new { attestId = createdId });
    }

    private static async Task<IResult> ListAttestsForEmployer(Guid id, int? take, IMediator mediator, CancellationToken ct)
    {
        var items = await mediator.Send(new ListEmployerAttestsQuery(id, take), ct);
        return Results.Ok(items);
    }

    private static async Task<IResult> DownloadAttestForEmployer(Guid id, Guid attestId, bool? inline, IMediator mediator, CancellationToken ct)
    {
        var content = await mediator.Send(new GetAttestContentQuery(attestId), ct);
        if (content is null) return Results.NotFound();
        var contentType = NormalizeContentType(content.Content, content.ContentType);
        var fileName = NormalizeFileName(content.FileName, attestId, contentType);
        if (inline == true)
        {
            return Results.File(content.Content, contentType);
        }
        return Results.File(content.Content, contentType, fileName);
    }

    private static string NormalizeContentType(byte[] data, string? original)
    {
        var ct = string.IsNullOrWhiteSpace(original) || string.Equals(original, "application/octet-stream", StringComparison.OrdinalIgnoreCase)
            ? null
            : original;
        if (ct is null)
        {
            if (data is { Length: >= 4 } && data[0] == 0x25 && data[1] == 0x50 && data[2] == 0x44 && data[3] == 0x46)
            {
                return "application/pdf";
            }
        }
        return ct ?? "application/pdf";
    }

    private static string NormalizeFileName(string? name, Guid attestId, string contentType)
    {
        var n = string.IsNullOrWhiteSpace(name) ? $"attest-{attestId}" : name!;
        if (string.Equals(contentType, "application/pdf", StringComparison.OrdinalIgnoreCase) && !n.EndsWith(".pdf", StringComparison.OrdinalIgnoreCase))
        {
            n += ".pdf";
        }
        return n;
    }

    private static async Task<IResult> UpsertEmployer(EmployerUpsertRequest req, IMediator mediator, CancellationToken ct)
    {
        var resp = await mediator.Send(new UpsertEmployerCommand(req.OrgNumber, req.Name), ct);
        return Results.Ok(resp);
    }

    private static async Task<IResult> ListEmployers(IMediator mediator, CancellationToken ct)
    {
        var resp = await mediator.Send(new ListEmployersQuery(), ct);
        return Results.Ok(resp);
    }

    private static async Task<Results<Ok<EmployerResponse>, NotFound>> GetEmployer(Guid id, IMediator mediator, CancellationToken ct)
    {
        var resp = await mediator.Send(new GetEmployerQuery(id), ct);
        if (resp is null) return TypedResults.NotFound();
        return TypedResults.Ok(resp);
    }

    private static async Task<IResult> ListEmployerUsers(Guid employerId, IMediator mediator, CancellationToken ct)
    {
        var resp = await mediator.Send(new ListEmployerUsersQuery(employerId), ct);
        return Results.Ok(resp);
    }

    private static async Task<Results<Ok<EmployerUserResponse>, NotFound>> GetEmployerUser(Guid employerId, Guid userId, IMediator mediator, CancellationToken ct)
    {
        var resp = await mediator.Send(new GetEmployerUserQuery(employerId, userId), ct);
        if (resp is null) return TypedResults.NotFound();
        return TypedResults.Ok(resp);
    }

    private static async Task<Results<Ok<EmployerUserResponse>, NotFound, BadRequest<string>>> UpsertEmployerUser(Guid employerId, EmployerUserUpsertRequest req, IMediator mediator, CancellationToken ct)
    {
        var resp = await mediator.Send(new UpsertEmployerUserCommand(employerId, req.ExternalObjectId, req.Email, req.Name, req.Role), ct);
        if (resp is null) return TypedResults.NotFound();
        return TypedResults.Ok(resp);
    }

    private static async Task<Results<NoContent, NotFound>> DeleteEmployerUser(Guid employerId, Guid userId, IMediator mediator, CancellationToken ct)
    {
        var ok = await mediator.Send(new DeleteEmployerUserCommand(employerId, userId), ct);
        if (!ok) return TypedResults.NotFound();
        return TypedResults.NoContent();
    }
}