using System.ComponentModel.DataAnnotations.Schema;
using System.Reflection;
using System.Text.RegularExpressions;

namespace ReC.Application.Common.Dto;

public static partial class PlaceholderExtensions
{
    [GeneratedRegex(@"\{#[^#]+#[^}]+\}")]
    private static partial Regex PlaceholderRegex();

    /// <summary>
    /// Replaces placeholders in the format <c>{#ANY_STRING#COLUMN_NAME}</c> with the corresponding
    /// property value resolved via <see cref="GetValueByColumnName{T}"/> from the provided objects.
    /// Values are converted to SQL-compatible string representations.
    /// If a placeholder cannot be resolved, it is replaced with <c>NULL</c>.
    /// </summary>
    public static string ReplacePlaceholders(this string str, params object?[] objects)
    {
        return PlaceholderRegex().Replace(str, match =>
        {
            var placeholder = match.Value;
            var inner = placeholder[2..^1]; // remove {# and }
            var lastHash = inner.LastIndexOf('#');
            var columnName = inner[(lastHash + 1)..];

            foreach (var obj in objects)
            {
                if (obj is null)
                    continue;

                var value = obj.GetValueByColumnName(columnName);
                if (value is not null)
                    return ToSqlLiteral(value);
            }

            return "NULL";
        });
    }

    private static string ToSqlLiteral(object value) => value switch
    {
        bool b => b ? "TRUE" : "FALSE",
        DateTime dt => dt.ToString("yyyy-MM-dd HH:mm:ss"),
        DateTimeOffset dto => dto.ToString("yyyy-MM-dd HH:mm:ss zzz"),
        _ => value.ToString() ?? string.Empty
    };

    /// <summary>
    /// Gets the value of a property by its column name defined in <see cref="ColumnAttribute"/>.
    /// Returns <c>null</c> if no property with the given column name exists.
    /// </summary>
    public static object? GetValueByColumnName<T>(this T obj, string columnName) where T : class
    {
        var property = obj.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance)
            .FirstOrDefault(p => p.GetCustomAttribute<ColumnAttribute>()?.Name == columnName);

        return property?.GetValue(obj);
    }
}