using System.Text.Json;
using Deal.Api.Endpoints.RequestModels;
using Deal.Api.Extensions;
using Deal.Api.Services;
using Deal.Modules.Kanban.Application.Models;
using Deal.Modules.Kanban.Application.Services;
using Deal.Modules.Tenants.Application.Models;

namespace Deal.Api.Endpoints;

/// <summary>
/// Эндпоинты контейнеров
/// </summary>
public static class ContainersEndpoints
{
    // Префикс группы контейнеров.
    private const string ContainersGroupPrefix = "/api/containers";

    // OpenAPI-тег группы.
    private const string OpenApiTag = "containers";

    // 400: отсутствующий/явный null name контейнера.
    private const string ContainerNameRequiredDetail = "Укажите название колонки";

    // 400 reorder: отсутствующий/явный null order.
    private const string ContainerOrderRequiredDetail = "Не указан порядок колонок";

    // 400 PATCH: тело не JSON-объект.
    private const string InvalidBodyDetail = "Тело запроса должно быть JSON-объектом";

    // Опции разбора PATCH-тела: web-дефолты (camelCase + регистронезависимость).
    private static readonly JsonSerializerOptions RequestJsonOptions = new(JsonSerializerDefaults.Web);

    /// <summary>
    /// Регистрирует группы /api/containers
    /// </summary>
    /// <param name="app">Построитель маршрутов приложения.</param>
    /// <returns>Построитель маршрутов для цепочки вызовов.</returns>
    public static IEndpointRouteBuilder MapContainersEndpoints(this IEndpointRouteBuilder app)
    {
        var containers = app.MapGroup(ContainersGroupPrefix).WithTags(OpenApiTag);
        containers.MapGet("", ListContainersAsync);
        containers.MapPost("", CreateContainerAsync);
        containers.MapPost("/reorder", ReorderContainersAsync);
        containers.MapGet("/state", GetColumnsStateAsync);
        containers.MapPatch("/{containerId}/state", PatchColumnStateAsync);
        containers.MapPost("/{containerId}/accept", AcceptSuggestedAsync);
        containers.MapPatch("/{containerId}", PatchContainerAsync);
        containers.MapDelete("/{containerId}", DeleteContainerAsync);
        return app;
    }

    // GET /api/containers?space=: список контейнеров пространства (или всех) со счётчиками.
    private static async Task<IResult> ListContainersAsync(
        string? space,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        return Results.Ok(new { items = await containers.ListAsync(space, ct) });
    }

    // POST /api/containers: создать контейнер; ответ {id}.
    private static async Task<IResult> CreateContainerAsync(
        ContainerCreateRequest body,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        if (body.Name is null)
        {
            return EndpointResults.BadRequest(ContainerNameRequiredDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        ContainerDto created = await containers.CreateAsync(
            new ContainerCreateDto(
                Name: body.Name,
                Description: body.Description ?? string.Empty,
                Color: body.Color,
                Space: body.Space ?? ContainerSpaces.Dashboard,
                Kind: body.Kind ?? ContainerKinds.Board,
                Suggested: body.Suggested ?? false,
                Rules: NormalizeWireRules(body.Rules),
                Note: body.Note ?? string.Empty),
            ct);

        await AuditAppender.AppendTenantAsync(context, AuditEvents.ContainerCreated, [AuditDetails.Set(AuditFields.ContainerId, created.Id), AuditDetails.Set(AuditFields.Name, created.Name)], ct);
        return Results.Ok(new { id = created.Id });
    }

    // PATCH /api/containers/{id}: частичное обновление; ответ {id}; 404 «Контейнер не найден».
    private static async Task<IResult> PatchContainerAsync(
        string containerId,
        JsonElement body,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        if (body.ValueKind != JsonValueKind.Object)
        {
            return EndpointResults.BadRequest(InvalidBodyDetail);
        }

        foreach (JsonProperty property in body.EnumerateObject())
        {
            if (string.Equals(property.Name, "name", StringComparison.OrdinalIgnoreCase)
                && property.Value.ValueKind == JsonValueKind.Null)
            {
                return EndpointResults.BadRequest(ContainerNameRequiredDetail);
            }
        }

        ContainerPatchRequest? patchBody;
        try
        {
            patchBody = body.Deserialize<ContainerPatchRequest>(RequestJsonOptions);
        }
        catch (JsonException)
        {
            return EndpointResults.BadRequest(InvalidBodyDetail);
        }

        if (patchBody is null)
        {
            return EndpointResults.BadRequest(InvalidBodyDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        ContainerDto updated = await containers.PatchAsync(
            containerId,
            new ContainerPatchDto(
                patchBody.Name,
                patchBody.Description,
                patchBody.Color,
                patchBody.Collapsed,
                patchBody.Suggested,
                patchBody.Note,
                NormalizeWireRules(patchBody.Rules),
                patchBody.Policy),
            ct);

        await AuditAppender.AppendTenantAsync(context, AuditEvents.ContainerUpdated, [AuditDetails.Set(AuditFields.ContainerId, updated.Id)], ct);
        return Results.Ok(new { id = updated.Id });
    }

    // POST /api/containers/{id}/accept: принять ИИ-предложение (suggested=false).
    private static async Task<IResult> AcceptSuggestedAsync(
        string containerId,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        ContainerDto accepted = await containers.AcceptSuggestedAsync(containerId, ct);

        await AuditAppender.AppendTenantAsync(context, AuditEvents.ContainerUpdated, [AuditDetails.Set(AuditFields.ContainerId, accepted.Id)], ct);
        return Results.Ok(accepted);
    }

    // DELETE /api/containers/{id}: удалить контейнер; карточки → «Неразобранное» новыми.
    private static async Task<IResult> DeleteContainerAsync(
        string containerId,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        int moved = await containers.DeleteAsync(containerId, ct);

        await AuditAppender.AppendTenantAsync(context, AuditEvents.ContainerDeleted, [AuditDetails.Set(AuditFields.ContainerId, containerId)], ct);
        return Results.Ok(new { ok = true, movedToInbox = moved });
    }

    // POST /api/containers/reorder: порядок контейнеров пространства; ответ {ok:true}.
    private static async Task<IResult> ReorderContainersAsync(
        OrderBody body,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        if (body.Order is null)
        {
            return EndpointResults.BadRequest(ContainerOrderRequiredDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        await containers.ReorderAsync(body.Space ?? ContainerSpaces.Dashboard, body.Order, ct);
        return Results.Ok(new { ok = true });
    }

    // GET /api/containers/state: свёрнутость/ширина всех колонок (colState).
    private static async Task<IResult> GetColumnsStateAsync(HttpContext context, CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        IReadOnlyDictionary<string, ColumnStateDto> state = await containers.GetColStateAsync(ct);

        var wire = new Dictionary<string, object>(StringComparer.Ordinal);
        foreach ((string colId, ColumnStateDto colState) in state)
        {
            wire[colId] = ToWireState(colState);
        }

        return Results.Ok(wire);
    }

    // PATCH /api/containers/{id}/state: merge патча в состояние колонки; ответ — состояние этой колонки.
    private static async Task<IResult> PatchColumnStateAsync(
        string containerId,
        ColStateBody body,
        HttpContext context,
        CancellationToken ct)
    {
        if (!context.HasUser())
        {
            return EndpointResults.Unauthorized(AuthHelpers.UnauthorizedDetail);
        }

        ContainersService containers = context.RequestServices.GetRequiredService<ContainersService>();
        ColumnStateDto merged = await containers.PatchColStateAsync(
            containerId,
            new ColumnStateDto(body.Collapsed, body.Width),
            ct);
        return Results.Ok(ToWireState(merged));
    }

    // Правила из wire → каноничный ContainerRulesDto: отсутствующие группы становятся пустыми списками.
    // rules: Правила из тела запроса (null — «не меняются/нет правил»).
    // Возвращает: Каноничные правила с не-null группами; null — правил в теле нет.
    private static ContainerRulesDto? NormalizeWireRules(ContainerRulesDto? rules)
    {
        if (rules is null)
        {
            return null;
        }

        return rules with
        {
            Mode = rules.Mode ?? string.Empty,
            Direction = rules.Direction ?? Array.Empty<string>(),
            Keywords = rules.Keywords ?? Array.Empty<string>(),
            Stack = rules.Stack ?? Array.Empty<string>(),
            Grade = rules.Grade ?? Array.Empty<string>(),
            Exclude = rules.Exclude ?? Array.Empty<string>(),
            Budget = rules.Budget is null ? null : rules.Budget with { Cur = rules.Budget.Cur ?? string.Empty },
            Levels = rules.Levels ?? Array.Empty<string>(),
            Locations = rules.Locations ?? Array.Empty<string>(),
            Types = rules.Types ?? Array.Empty<string>(),
            Prices = rules.Prices is null ? null : rules.Prices with { Cur = rules.Prices.Cur ?? string.Empty },
        };
    }

    // Состояние колонки → wire-объект только с заданными полями (collapsed/width), без null.
    // state: Состояние колонки (могут быть null-поля).
    // Возвращает: Словарь из не-null полей состояния.
    private static Dictionary<string, object> ToWireState(ColumnStateDto state)
    {
        var wire = new Dictionary<string, object>();
        if (state.Collapsed is { } collapsed)
        {
            wire["collapsed"] = collapsed;
        }

        if (state.Width is not null)
        {
            wire["width"] = state.Width;
        }

        return wire;
    }
}