using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text.RegularExpressions;
using Jint.Runtime;
using Newtonsoft.Json.Linq;
using Xunit;

namespace Jint.Tests.Test262
{
    public abstract class Test262Test
    {
        private static readonly string[] Sources;

        private static readonly string BasePath;

        private static readonly TimeZoneInfo _pacificTimeZone;

        private static readonly Dictionary<string, string> _skipReasons =
            new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);

        static Test262Test()
        {
            //NOTE: The Date tests in test262 assume the local timezone is Pacific Standard Time
            _pacificTimeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

            var assemblyPath = new Uri(typeof(Test262Test).GetTypeInfo().Assembly.CodeBase).LocalPath;
            var assemblyDirectory = new FileInfo(assemblyPath).Directory;

            BasePath = assemblyDirectory.Parent.Parent.Parent.FullName;

            string[] files =
            {
                @"harness\sta.js",
                @"harness\assert.js",
                @"harness\propertyHelper.js",
                @"harness\compareArray.js",
                @"harness\decimalToHexString.js",
            };

            Sources = new string[files.Length];
            for (var i = 0; i < files.Length; i++)
            {
                Sources[i] = File.ReadAllText(Path.Combine(BasePath, files[i]));
            }

            var content = File.ReadAllText(Path.Combine(BasePath, "test/skipped.json"));
            var doc = JArray.Parse(content);
            foreach (var entry in doc.Values<JObject>())
            {
                _skipReasons[entry["source"].Value<string>()] = entry["reason"].Value<string>();
            }
        }

        protected void RunTestCode(string code, bool strict)
        {
            var engine = new Engine(cfg => cfg
                .LocalTimeZone(_pacificTimeZone)
                .Strict(strict));

            for (int i = 0; i < Sources.Length; ++i)
            {
                engine.Execute(Sources[i]);
            }

            string lastError = null;

            bool negative = code.IndexOf("negative:", StringComparison.Ordinal) > -1;
            try
            {
                engine.Execute(code);
            }
            catch (JavaScriptException j)
            {
                lastError = TypeConverter.ToString(j.Error);
            }
            catch (Exception e)
            {
                lastError = e.ToString();
            }

            if (negative)
            {
                Assert.NotNull(lastError);
            }
            else
            {
                Assert.Null(lastError);
            }
        }

        protected void RunTestInternal(SourceFile sourceFile)
        {
            RunTestCode(sourceFile.Code);
        }

        private void RunTestCode(string code)
        {
            if (code.IndexOf("onlyStrict", StringComparison.Ordinal) < 0)
            {
                RunTestCode(code, strict: false);
            }

            if (code.IndexOf("noStrict", StringComparison.Ordinal) < 0)
            {
                RunTestCode(code, strict: true);
            }
        }

        public static IEnumerable<object[]> SourceFiles(string pathPrefix, bool skipped)
        {
            var results = new List<object[]>();
            var fixturesPath = Path.Combine(BasePath, "test");
            var searchPath = Path.Combine(fixturesPath, pathPrefix);
            var files = Directory.GetFiles(searchPath, "*", SearchOption.AllDirectories);

            foreach (var file in files)
            {
                var name = file.Substring(fixturesPath.Length + 1).Replace("\\", "/");
                bool skip = _skipReasons.TryGetValue(name, out var reason);

                var code = skip ? "" : File.ReadAllText(file);

                var features = Regex.Match(code, "features: \\[(.+?)\\]");
                if (features.Success)
                {
                    var items = features.Groups[1].Captures[0].Value.Split(",");
                    foreach (var item in items.Select(x => x.Trim()))
                    {
                        switch (item)
                        {
                            // TODO implement
                            case "cross-realm":
                                skip = true;
                                reason = "realms not implemented";
                                break;
                            case "tail-call-optimization":
                                skip = true;
                                reason = "tail-calls not implemented";
                                break;
                            case "class":
                                skip = true;
                                reason = "class keyword not implemented";
                                break;
                            case "Symbol.species":
                                skip = true;
                                reason = "Symbol.species not implemented";
                                break;
                            case "Proxy":
                                skip = true;
                                reason = "Proxies not implemented";
                                break;
                            case "object-spread":
                                skip = true;
                                reason = "Object spread not implemented";
                                break;
                            case "Symbol.unscopables":
                                skip = true;
                                reason = "Symbol.unscopables not implemented";
                                break;
                            case "Symbol.match":
                                skip = true;
                                reason = "Symbol.match not implemented";
                                break;
                            case "Symbol.matchAll":
                                skip = true;
                                reason = "Symbol.matchAll not implemented";
                                break;
                            case "Symbol.split":
                                skip = true;
                                reason = "Symbol.split not implemented";
                                break;
                            case "String.prototype.matchAll":
                                skip = true;
                                reason = "proposal stage";
                                break;
                            case "Symbol.search":
                                skip = true;
                                reason = "Symbol.search not implemented";
                                break;
                            case "Symbol.replace":
                                skip = true;
                                reason = "Symbol.replace not implemented";
                                break;
                            case "Symbol.toStringTag":
                                skip = true;
                                reason = "Symbol.toStringTag not implemented";
                                break;
                            case "BigInt":
                                skip = true;
                                reason = "BigInt not implemented";
                                break;
                            case "generators":
                                skip = true;
                                reason = "generators not implemented";
                                break;
                            case "destructuring-binding":
                                skip = true;
                                reason = "destructuring-binding not implemented";
                                break;
                            case "let":
                                skip = true;
                                reason = "let not implemented";
                                break;
                            case "async-functions":
                                skip = true;
                                reason = "async-functions not implemented";
                                break;
                        }
                    }
                }

                if (name.StartsWith("built-ins/String/raw/"))
                {
                    skip = true;
                    reason = "requires template string";
                }

                if (code.IndexOf("SpecialCasing.txt") > -1)
                {
                    skip = true;
                    reason = "SpecialCasing.txt not implemented";
                }

                var sourceFile = new SourceFile(
                    name,
                    file,
                    skip,
                    reason,
                    code);

                if (skipped == sourceFile.Skip)
                {
                    results.Add(new object[]
                    {
                        sourceFile
                    });
                }
            }

            return results;
        }
    }

    public class SourceFile
    {
        public SourceFile(
            string source,
            string fullPath,
            bool skip,
            string reason,
            string code)
        {
            Skip = skip;
            Source = source;
            Reason = reason;
            FullPath = fullPath;
            Code = code;
        }

        public string Source { get; }
        public bool Skip { get; }
        public string Reason { get; }
        public string FullPath { get; }
        public string Code { get; }

        public override string ToString()
        {
            return Source;
        }
    }
}