using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using Sozsoft.Platform;

namespace Sozsoft.Mcp;

/// <summary>
/// query_list'in DevExtreme bicimindeki (JSON) sort/group/summary girdilerini ekranin select
/// ucunun bekledigi metin bicimine (<c>Alan desc|Alan2 asc</c>) cevirir. Arayuzde ayni donusumu
/// <c>ui/src/views/list/Utils.ts</c> yapar; select ucu JSON'u tanimaz ve ORDER BY'a oldugu gibi
/// ekler. JSON olmayan girdi zaten metin bicimindedir, dokunulmaz. Bozuk girdi
/// <see cref="JsonException"/> ya da <see cref="InvalidOperationException"/> atar.
/// </summary>
internal static class McpLoadOptions
{
    public static string? ToSort(string? json)
        => Convert(json, item => $"{Selector(item)} {Direction(item)}");

    public static string? ToGroup(string? json)
        => Convert(json, item =>
        {
            var isExpanded = item.TryGetProperty("isExpanded", out var expanded) && expanded.ValueKind == JsonValueKind.True;
            var interval = item.TryGetProperty("groupInterval", out var value) && value.ValueKind == JsonValueKind.String
                ? $" {value.GetString()}"
                : string.Empty;

            return $"{Selector(item)} {Direction(item)} {(isExpanded ? "true" : "false")}{interval}";
        });

    public static string? ToSummary(string? json)
        => Convert(json, item => $"{Selector(item)} {Text(item, "summaryType")}");

    private static string? Convert(string? json, Func<JsonElement, string> map)
    {
        var value = json?.Trim();
        if (string.IsNullOrEmpty(value))
        {
            return null;
        }

        if (!value.StartsWith('['))
        {
            return value;
        }

        using var document = JsonDocument.Parse(value);

        var parts = document.RootElement.EnumerateArray()
            .Where(item => item.ValueKind == JsonValueKind.Object)
            .Select(map)
            .ToList();

        return parts.Count == 0 ? null : string.Join(PlatformConsts.MultiValueDelimiter, parts);
    }

    private static string Selector(JsonElement item) => Text(item, "selector");

    private static string Direction(JsonElement item)
        => item.TryGetProperty("desc", out var desc) && desc.ValueKind == JsonValueKind.True ? "desc" : "asc";

    private static string Text(JsonElement item, string name)
    {
        var text = item.TryGetProperty(name, out var value) && value.ValueKind == JsonValueKind.String ? value.GetString() : null;

        // Bosluk ve ayirici metin biciminin sozdizimidir; alan adinda bulunamazlar.
        if (string.IsNullOrWhiteSpace(text) || text.Any(c => char.IsWhiteSpace(c) || c == PlatformConsts.MultiValueDelimiter))
        {
            throw new JsonException(name);
        }

        return text;
    }
}