using System;
using System.Globalization;
using System.IO;
using System.Text.RegularExpressions;

namespace UltraCombos
{
    public static class DotNetEnv
    {
        private static readonly Regex lineRegex = new Regex(
            @"(?:^|^)\s*(?:export\s+)?([\w.-]+)(?:\s*=\s*?|:\s+?)(\s*'(?:\\'|[^'])*'|\s*""(?:\\""|[^""])*""|\s*`(?:\\`|[^`])*`|[^#\r\n]+)?\s*(?:#.*)?(?:$|$)",
            RegexOptions.Multiline | RegexOptions.Compiled);

        public static void Load(string path = ".env")
        {
            if (!File.Exists(path))
            {
                return;
            }

            var src = File.ReadAllText(path);

            src = src.Replace("\r\n", "\n").Replace("\r", "\n");

            var keys = new System.Collections.Generic.List<string>();
            var matches = lineRegex.Matches(src);
            foreach (Match match in matches)
            {
                var key = match.Groups[1].Value;
                var value = match.Groups[2].Value.Trim();

                if (string.IsNullOrEmpty(key))
                {
                    continue;
                }

                var maybeQuote = value.Length > 0 ? value[0] : (char?)null;

                value = Regex.Replace(value, @"^(['""`])([\s\S]*)\1$", "$2");

                if (maybeQuote == '"')
                {
                    value = value.Replace("\\n", "\n").Replace("\\r", "\r");
                }

                Environment.SetEnvironmentVariable(key, value);
                keys.Add(key);
            }
            Log.Info("DotNetEnv", $"Loaded environment variable:\n{string.Join("\n", keys)}");
        }

        public static bool TryGet(string key, out string value)
        {
            value = Environment.GetEnvironmentVariable(key);
            return !string.IsNullOrEmpty(value);
        }

        public static bool TryGetAs<T>(string key, out T value) where T : struct
        {
            var raw = Environment.GetEnvironmentVariable(key);
            if (string.IsNullOrEmpty(raw))
            {
                value = default;
                return false;
            }

            try
            {
                value = (T)Convert.ChangeType(raw, typeof(T), CultureInfo.InvariantCulture);
                return true;
            }
            catch
            {
                value = default;
                return false;
            }
        }
    }
}