using Novelly.Api.Beats;
using Novelly.Api.Common;
using Novelly.Api.Common.Validation;
using Novelly.Api.Locations;
using Novelly.Api.Tags;

namespace Novelly.Api.Chapters;

public record ChapterSummaryResponse(
    Guid Id,
    Guid NovelId,
    int Number,
    ChapterKind Kind,
    int? DisplayNumber,
    string Title,
    string? Summary,
    IReadOnlyList<LocationResponse> Locations,
    DraftStatus Status,
    int? TargetWordCount,
    int BeatCount,
    int WordCount,
    IReadOnlyList<TagResponse> Tags,
    DateTimeOffset UpdatedAt);

public record ChapterResponse(
    Guid Id,
    Guid NovelId,
    int Number,
    ChapterKind Kind,
    int? DisplayNumber,
    string Title,
    string? Summary,
    IReadOnlyList<LocationResponse> Locations,
    string? Notes,
    DraftStatus Status,
    int? TargetWordCount,
    IReadOnlyList<BeatResponse> Beats,
    string? Prose,
    int WordCount,
    IReadOnlyList<TagResponse> Tags,
    DateTimeOffset UpdatedAt);

public record CreateChapterRequest(
    string Title,
    int? Number = null,
    ChapterKind Kind = ChapterKind.Body,
    string? Summary = null,
    IReadOnlyList<string>? Locations = null,
    string? Notes = null,
    DraftStatus Status = DraftStatus.Planned,
    int? TargetWordCount = null,
    string? Prose = null,
    IReadOnlyList<string>? Tags = null);

public class CreateChapterRequestValidator : IModelValidator<CreateChapterRequest>
{
    public ValidationResult Validate(CreateChapterRequest model)
    {
        var result = new ValidationResult();

        result.AddRequiredTextErrors("Title", "Title", model.Title, 200);
        ChapterValidation.OptionalFields(model.Number, model.Summary, model.Locations, model.Notes, model.TargetWordCount, model.Prose, model.Tags, result);

        return result;
    }
}

public record UpdateChapterRequest(
    string? Title = null,
    int? Number = null,
    ChapterKind? Kind = null,
    string? Summary = null,
    IReadOnlyList<string>? Locations = null,
    string? Notes = null,
    DraftStatus? Status = null,
    int? TargetWordCount = null,
    string? Prose = null,
    IReadOnlyList<string>? Tags = null);

public class UpdateChapterRequestValidator : IModelValidator<UpdateChapterRequest>
{
    public ValidationResult Validate(UpdateChapterRequest model)
    {
        var result = new ValidationResult();

        result.AddUnclearableTextErrors("Title", "Title", model.Title, "a chapter", 200);
        ChapterValidation.OptionalFields(model.Number, model.Summary, model.Locations, model.Notes, model.TargetWordCount, model.Prose, model.Tags, result);

        return result;
    }
}

file static class ChapterValidation
{
    public static void OptionalFields(
        int? number, string? summary, IReadOnlyList<string>? locations, string? notes, int? targetWordCount, string? prose,
        IReadOnlyList<string>? tags, ValidationResult result)
    {
        if (number is <= 0)
            result.AddError("Number", "'Number' must be greater than zero.");

        if (summary is { Length: > 20000 })
            result.AddError("Summary", "'Summary' must be 20,000 characters or fewer.");

        if (locations is not null && locations.Any(string.IsNullOrWhiteSpace))
            result.AddError("Locations", "'Locations' must not contain blank entries.");

        if (notes is { Length: > 20000 })
            result.AddError("Notes", "'Notes' must be 20,000 characters or fewer.");

        if (targetWordCount is < 0)
            result.AddError("TargetWordCount", "'Target Word Count' must be zero or greater.");

        if (prose is { Length: > 200000 })
            result.AddError("Prose", "'Prose' must be 200,000 characters or fewer.");

        if (tags is not null && tags.Any(string.IsNullOrWhiteSpace))
            result.AddError("Tags", "'Tags' must not contain blank entries.");
    }
}

public static class ChapterMapping
{
    public static ChapterResponse ToResponse(this Chapter c, int? displayNumber = null) => new(
        c.Id, c.NovelId, c.Number, c.Kind, displayNumber, c.Title, c.Summary,
        [.. c.Locations.OrderBy(l => l.Name).Select(l => l.ToResponse())],
        c.Notes,
        c.Status, c.TargetWordCount,
        [.. c.Beats.OrderBy(b => b.SortOrder).Select(b => b.ToResponse())],
        c.Prose, c.WordCount,
        [.. c.Tags.OrderBy(t => t.Name).Select(t => t.ToResponse())],
        c.UpdatedAt);

    public static ChapterSummaryResponse ToSummaryResponse(this Chapter c, int? displayNumber = null) => new(
        c.Id, c.NovelId, c.Number, c.Kind, displayNumber, c.Title, c.Summary,
        [.. c.Locations.OrderBy(l => l.Name).Select(l => l.ToResponse())],
        c.Status, c.TargetWordCount,
        c.Beats.Count, c.WordCount,
        [.. c.Tags.OrderBy(t => t.Name).Select(t => t.ToResponse())],
        c.UpdatedAt);

    public static int CountWords(string? prose) =>
        string.IsNullOrWhiteSpace(prose)
            ? 0
            : prose.Split((char[]?)null, StringSplitOptions.RemoveEmptyEntries).Length;
}