using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace BriarQueen.Framework.Extensions
{
    public static class StringExtensions
    {
        private static readonly string[] Prefixes =
        {
            "ENV_",
            "PUZ_",
            "SUB_",
            "UI_",
            "SFX_",
            "BGM_",
            "BOOK_",
            "CLUE_",
            "PHOTO_"
        };

        private static readonly IReadOnlyDictionary<string, string> Overrides =
            new Dictionary<string, string>
            {
                { "Pumphouse", "Pump House" },
                { "Lockbox", "Lockbox" },
                { "Codex", "Codex" },
                { "UIFX", "UI FX" },
                { "SFX", "SFX" },
                { "BGM", "BGM" }
            };

        public static string Prettify(this string value)
        {
            if (string.IsNullOrWhiteSpace(value))
                return string.Empty;

            value = StripPrefix(value);
            value = value.Replace("_", " ");
            value = AddSpacing(value);
            value = Regex.Replace(value, @"\s+", " ").Trim();

            if (value.Length == 0)
                return string.Empty;

            var words = value.Split(' ');
            var sb = new StringBuilder();

            for (int i = 0; i < words.Length; i++)
            {
                var word = words[i];

                if (string.IsNullOrWhiteSpace(word))
                    continue;

                string formatted = FormatWord(word);

                sb.Append(formatted);

                if (i < words.Length - 1)
                    sb.Append(' ');
            }

            return sb.ToString();
        }

        private static string StripPrefix(string value)
        {
            foreach (var prefix in Prefixes)
            {
                if (value.StartsWith(prefix))
                    return value.Substring(prefix.Length);
            }

            return value;
        }

        private static string AddSpacing(string value)
        {
            value = Regex.Replace(value, "([a-z0-9])([A-Z])", "$1 $2");
            value = Regex.Replace(value, "([A-Z]+)([A-Z][a-z])", "$1 $2");
            value = Regex.Replace(value, "([a-zA-Z])([0-9])", "$1 $2");
            value = Regex.Replace(value, "([0-9])([a-zA-Z])", "$1 $2");

            return value;
        }

        private static string FormatWord(string word)
        {
            if (Overrides.TryGetValue(word, out var overrideValue))
                return overrideValue;

            if (word.Length > 1 && word.ToUpperInvariant() == word)
                return word;

            return char.ToUpperInvariant(word[0]) + word.Substring(1).ToLowerInvariant();
        }
    }
}