using System.Diagnostics.CodeAnalysis;
using ErsatzTV.Core;
using ErsatzTV.Core.Errors;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace ErsatzTV.Extensions;

/// <summary>
///     REST status-code mapping helpers for the JSON write/read API (slice #2a).
///     These are additive and must not change the behavior of the existing
///     <see cref="EitherToActionResult" /> / <see cref="OptionToActionResult" /> helpers,
///     which IptvController and other read endpoints depend on.
/// </summary>
[SuppressMessage("ReSharper", "VSTHRD003")]
public static class ApiResults
{
    /// <summary>
    ///     Maps a failure to 404 when it is a <see cref="NotFoundError" />, 412 when it is a
    ///     <see cref="PreconditionFailedError" /> (optimistic-concurrency mismatch, issue #253),
    ///     otherwise 422.
    /// </summary>
    public static IActionResult ToErrorResult(this BaseError error) =>
        error switch
        {
            NotFoundError =>
                new NotFoundObjectResult(CreateProblemDetails(404, "Resource not found", error.Value)),
            PreconditionFailedError =>
                new ObjectResult(CreateProblemDetails(412, "Precondition Failed", error.Value))
                {
                    StatusCode = StatusCodes.Status412PreconditionFailed
                },
            _ =>
                new UnprocessableEntityObjectResult(CreateProblemDetails(422, "Validation failed", error.Value))
        };

    /// <summary>Right: 201 Created with a Location header and body; Left: 404 (NotFound) or 422.</summary>
    public static IActionResult ToCreatedResult<TR>(
        this Either<BaseError, TR> either,
        Func<TR, string> location,
        Func<TR, object> body) =>
        either.Match(
            Left: error => error.ToErrorResult(),
            Right: value => new CreatedResult(location(value), body(value)));

    /// <summary>Right: 200 with body; Left: 404 (NotFound) or 422.</summary>
    public static IActionResult ToUpdatedResult<TR>(this Either<BaseError, TR> either) =>
        either.Match(
            Left: error => error.ToErrorResult(),
            Right: value => (IActionResult)new OkObjectResult(value));

    /// <summary>Right(Unit): 204 No Content; Left: 404 (NotFound) or 422.</summary>
    public static IActionResult ToDeletedResult(this Either<BaseError, Unit> either) =>
        either.Match(
            Left: error => error.ToErrorResult(),
            Right: _ => (IActionResult)new NoContentResult());

    /// <summary>Some: 200 with body; None: 404.</summary>
    public static IActionResult ToGetResult<T>(this Option<T> option) =>
        option.Match(
            Some: value => (IActionResult)new OkObjectResult(value),
            None: () => NotFoundProblem());

    public static IActionResult NotFoundProblem(string detail = "Resource not found") =>
        new NotFoundObjectResult(CreateProblemDetails(404, "Resource not found", detail));

    /// <summary>
    ///     409 <see cref="ProblemDetails" /> directly — for a mutation that races a background operation
    ///     holding a lock (e.g. a playout build in flight). Mirrors <see cref="NotFoundProblem" />.
    /// </summary>
    public static IActionResult ConflictProblem(string title, string detail) =>
        new ConflictObjectResult(CreateProblemDetails(409, title, detail));

    private static ProblemDetails CreateProblemDetails(int status, string title, string detail) =>
        new()
        {
            Status = status,
            Title = title,
            Detail = detail
        };
}