using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text.Json;
using Microsoft.Extensions.Localization;
using Sozsoft.Platform;
using Sozsoft.Platform.Entities;
using Sozsoft.Platform.ListForms;
using Sozsoft.Platform.Localization;

namespace Sozsoft.Reports.PredefinedReports;

internal static class DynamicReportGridStateHelper
{
    public interface IReportColumnWidth
    {
        ListFormField Field { get; }
        bool IsImage { get; }
        float ImageWidth { get; }
    }

    public static string GetFilterName(ListForm listForm, string prefix) =>
        $"{prefix}-{GetStateStorageKey(listForm)}";

    public static List<ListFormField> GetVisibleFields(
        IReadOnlyList<ListFormField> availableFields,
        string gridStateJson)
    {
        if (!TryGetColumnStates(gridStateJson, out var statesByField))
        {
            return availableFields
                .Where(x => x.Visible == true)
                .ToList();
        }

        return availableFields
            .Where(field => statesByField.TryGetValue(field.FieldName, out var state)
                ? state.Visible
                : field.Visible == true)
            .OrderBy(field => statesByField.TryGetValue(field.FieldName, out var state)
                ? state.VisibleIndex
                : int.MaxValue)
            .ToList();
    }

    public static List<ListFormField> GetGroupedFields(
        IReadOnlyList<ListFormField> availableFields,
        string gridStateJson,
        string groupParameter)
    {
        var groupedFields = new List<ListFormField>();
        var groupedFieldNames = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

        foreach (var field in GetGroupFieldsFromParameter(availableFields, groupParameter))
        {
            AddGroupedField(field);
        }

        if (TryGetColumnStates(gridStateJson, out var statesByField))
        {
            foreach (var field in availableFields.Where(field =>
                statesByField.TryGetValue(field.FieldName, out var state) &&
                state.GroupIndex.HasValue)
                .OrderBy(field => statesByField[field.FieldName].GroupIndex)
                .ThenBy(field => statesByField[field.FieldName].VisibleIndex))
            {
                AddGroupedField(field);
            }
        }

        foreach (var field in availableFields
            .Select(field => new { Field = field, GroupIndex = GetConfiguredGroupIndex(field) })
            .Where(x => x.GroupIndex.HasValue)
            .OrderBy(x => x.GroupIndex)
            .Select(x => x.Field))
        {
            AddGroupedField(field);
        }

        return groupedFields;

        void AddGroupedField(ListFormField field)
        {
            if (!string.IsNullOrWhiteSpace(field?.FieldName) && groupedFieldNames.Add(field.FieldName))
            {
                groupedFields.Add(field);
            }
        }
    }

    public static Dictionary<string, float> GetColumnWidths(string gridStateJson, string columnWidthsJson = null)
    {
        var widths = TryGetColumnStates(gridStateJson, out var statesByField)
            ? statesByField
                .Where(x => x.Value.Width.HasValue && x.Value.Width.Value > 0)
                .ToDictionary(x => x.Key, x => x.Value.Width.Value, StringComparer.OrdinalIgnoreCase)
            : new Dictionary<string, float>(StringComparer.OrdinalIgnoreCase);

        foreach (var item in ParseColumnWidths(columnWidthsJson))
        {
            widths[item.Key] = item.Value;
        }

        return widths;
    }

    public static float[] CalculateWidths<TColumn>(
        IReadOnlyList<TColumn> columns,
        float pageWidth,
        IStringLocalizer<PlatformResource> localizer,
        IReadOnlyDictionary<string, float> stateWidths = null)
        where TColumn : IReportColumnWidth
    {
        if (columns.Count == 0)
        {
            return [];
        }

        var ideal = columns
            .Select(column => column.IsImage
                ? column.ImageWidth
                : GetPreferredColumnWidth(column.Field, localizer, stateWidths))
            .ToArray();
        var total = ideal.Sum();
        if (total <= 0)
        {
            return columns.Select(_ => pageWidth / columns.Count).ToArray();
        }

        return ideal.Select(width => pageWidth * width / total).ToArray();
    }

    public static float GetPreferredColumnWidth(
        ListFormField field,
        IStringLocalizer<PlatformResource> localizer = null,
        IReadOnlyDictionary<string, float> stateWidths = null)
    {
        var caption = localizer == null
            ? (string.IsNullOrWhiteSpace(field.CaptionName) ? field.FieldName : field.CaptionName)
            : DynamicReportImageHelper.GetLocalizedFieldCaption(field, localizer);
        var name = field.FieldName ?? string.Empty;
        var calculatedWidth = CalculateTextColumnWidth(field, caption, name);

        if (!string.IsNullOrWhiteSpace(field.FieldName) &&
            stateWidths?.TryGetValue(field.FieldName, out var stateWidth) == true &&
            stateWidth > 0)
        {
            return Math.Max(stateWidth, 40F);
        }

        if (field.Width > 0)
        {
            return Math.Max(field.Width.Value, 40F);
        }

        return calculatedWidth;
    }

    private static string GetStateStorageKey(ListForm listForm)
    {
        if (!string.IsNullOrWhiteSpace(listForm.StateStoringJson))
        {
            try
            {
                using var document = JsonDocument.Parse(listForm.StateStoringJson);
                if (TryGetProperty(document.RootElement, "storageKey", out var storageKey) &&
                    storageKey.ValueKind == JsonValueKind.String &&
                    !string.IsNullOrWhiteSpace(storageKey.GetString()))
                {
                    return storageKey.GetString();
                }
            }
            catch (JsonException)
            {
                // Fall back to the same default value used by GridOptionsDto.
            }
        }

        return $"listFormGridStorage-{listForm.ListFormCode}";
    }

    private static bool TryGetColumnStates(
        string gridStateJson,
        out Dictionary<string, GridColumnState> statesByField)
    {
        statesByField = null;
        if (string.IsNullOrWhiteSpace(gridStateJson))
        {
            return false;
        }

        try
        {
            using var document = JsonDocument.Parse(gridStateJson);
            if (!TryGetProperty(document.RootElement, "columns", out var columns) ||
                columns.ValueKind != JsonValueKind.Array)
            {
                return false;
            }

            var states = new List<GridColumnState>();
            AddColumnStates(columns, true, states);
            statesByField = states
                .Where(x => !string.IsNullOrWhiteSpace(x.FieldName))
                .GroupBy(x => x.FieldName, StringComparer.OrdinalIgnoreCase)
                .ToDictionary(x => x.Key, x => x.First(), StringComparer.OrdinalIgnoreCase);
            return statesByField.Count > 0;
        }
        catch (JsonException)
        {
            return false;
        }
    }

    private static void AddColumnStates(JsonElement columns, bool parentVisible, ICollection<GridColumnState> states)
    {
        foreach (var column in columns.EnumerateArray())
        {
            var visible = parentVisible &&
                          (!TryGetProperty(column, "visible", out var visibleProperty) ||
                           visibleProperty.ValueKind != JsonValueKind.False);
            var fieldName = GetColumnFieldName(column);
            var visibleIndex = TryGetProperty(column, "visibleIndex", out var visibleIndexProperty) &&
                               visibleIndexProperty.TryGetInt32(out var value)
                ? value
                : states.Count;
            var groupIndex = TryGetProperty(column, "groupIndex", out var groupIndexProperty) &&
                             groupIndexProperty.TryGetInt32(out var groupValue)
                ? groupValue
                : (int?)null;
            var width = TryGetProperty(column, "width", out var widthProperty) &&
                        TryGetFloat(widthProperty, out var widthValue)
                ? widthValue
                : (float?)null;

            if (!string.IsNullOrWhiteSpace(fieldName))
            {
                states.Add(new GridColumnState(fieldName, visible, visibleIndex, groupIndex, width));
            }

            if (TryGetProperty(column, "columns", out var childColumns) &&
                childColumns.ValueKind == JsonValueKind.Array)
            {
                AddColumnStates(childColumns, visible, states);
            }
        }
    }

    private static string GetColumnFieldName(JsonElement column)
    {
        if (TryGetProperty(column, "dataField", out var dataField) &&
            dataField.ValueKind == JsonValueKind.String)
        {
            return dataField.GetString();
        }

        if (TryGetProperty(column, "name", out var name) &&
            name.ValueKind == JsonValueKind.String)
        {
            return name.GetString();
        }

        return null;
    }

    private static bool TryGetFloat(JsonElement element, out float value)
    {
        if (element.ValueKind == JsonValueKind.Number && element.TryGetSingle(out value))
        {
            return true;
        }

        if (element.ValueKind == JsonValueKind.String &&
            float.TryParse(element.GetString(), System.Globalization.NumberStyles.Float, System.Globalization.CultureInfo.InvariantCulture, out value))
        {
            return true;
        }

        value = 0;
        return false;
    }

    private static float CalculateTextColumnWidth(ListFormField field, string caption, string name)
    {
        if (field.SourceDbType == DbType.Boolean)
        {
            return Math.Max(75F, MeasureTextWidth(caption, 7.2F, 30F, 68F, 100F));
        }

        if (DynamicReportImageHelper.IsNumeric(field.SourceDbType))
        {
            return Math.Max(70F, MeasureTextWidth(caption, 7.2F, 30F, 68F, 120F));
        }

        if (field.SourceDbType is DbType.Date or DbType.DateTime or DbType.DateTime2 or DbType.DateTimeOffset)
        {
            return Math.Max(115F, MeasureTextWidth(caption, 7.2F, 30F, 90F, 145F));
        }

        return Math.Max(
            MeasureTextWidth(caption, 7.2F, 30F, 85F, 220F),
            MeasureTextWidth(name, 5.6F, 28F, 85F, 180F));
    }

    private static float MeasureTextWidth(
        string value,
        float characterWidth,
        float padding,
        float minimum,
        float maximum)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return 0;
        }

        return Math.Clamp(value.Trim().Length * characterWidth + padding, minimum, maximum);
    }

    private static Dictionary<string, float> ParseColumnWidths(string columnWidthsJson)
    {
        var widths = new Dictionary<string, float>(StringComparer.OrdinalIgnoreCase);
        if (string.IsNullOrWhiteSpace(columnWidthsJson))
        {
            return widths;
        }

        try
        {
            using var document = JsonDocument.Parse(columnWidthsJson);
            if (document.RootElement.ValueKind == JsonValueKind.Object)
            {
                foreach (var property in document.RootElement.EnumerateObject())
                {
                    if (TryGetFloat(property.Value, out var width) && width > 0)
                    {
                        widths[property.Name] = width;
                    }
                }
            }
            else if (document.RootElement.ValueKind == JsonValueKind.Array)
            {
                AddColumnWidths(document.RootElement, widths);
            }
        }
        catch (JsonException)
        {
        }

        return widths;
    }

    private static void AddColumnWidths(JsonElement columns, IDictionary<string, float> widths)
    {
        foreach (var column in columns.EnumerateArray())
        {
            var fieldName = GetColumnFieldName(column);
            if (!string.IsNullOrWhiteSpace(fieldName) &&
                TryGetProperty(column, "width", out var widthProperty) &&
                TryGetFloat(widthProperty, out var width) &&
                width > 0)
            {
                widths[fieldName] = width;
            }

            if (TryGetProperty(column, "columns", out var childColumns) &&
                childColumns.ValueKind == JsonValueKind.Array)
            {
                AddColumnWidths(childColumns, widths);
            }
        }
    }

    private static List<ListFormField> GetGroupFieldsFromParameter(
        IReadOnlyList<ListFormField> availableFields,
        string groupParameter)
    {
        var result = new List<ListFormField>();
        if (string.IsNullOrWhiteSpace(groupParameter))
        {
            return result;
        }

        var fieldsByName = availableFields
            .Where(x => !string.IsNullOrWhiteSpace(x.FieldName))
            .ToDictionary(x => x.FieldName, StringComparer.OrdinalIgnoreCase);

        foreach (var group in groupParameter.Split(
            PlatformConsts.MultiValueDelimiter,
            StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
        {
            var parts = group.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
            if (parts.Length > 0 && fieldsByName.TryGetValue(parts[0], out var field))
            {
                result.Add(field);
            }
        }

        return result;
    }

    private static int? GetConfiguredGroupIndex(ListFormField field)
    {
        if (string.IsNullOrWhiteSpace(field.GroupingJson))
        {
            return null;
        }

        try
        {
            var grouping = JsonSerializer.Deserialize<ColumnGroupingDto>(field.GroupingJson, new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true
            });
            return grouping?.GroupIndex;
        }
        catch (JsonException)
        {
            return null;
        }
    }

    private static bool TryGetProperty(JsonElement element, string name, out JsonElement value)
    {
        if (element.ValueKind == JsonValueKind.Object)
        {
            foreach (var property in element.EnumerateObject())
            {
                if (string.Equals(property.Name, name, StringComparison.OrdinalIgnoreCase))
                {
                    value = property.Value;
                    return true;
                }
            }
        }

        value = default;
        return false;
    }

    private sealed record GridColumnState(string FieldName, bool Visible, int VisibleIndex, int? GroupIndex, float? Width);
}