using System;
using System.Collections.Generic;
using System.Reflection;
using ServiceStack.Configuration;
using ServiceStack.Platforms;
using ServiceStack.Web;

namespace ServiceStack;

public class Platform
{
    public static Platform Instance =
#if NETCORE
        new PlatformNetCore();
#else
        new PlatformNet();
#endif

    public virtual HashSet<string> GetRazorNamespaces()
    {
        return new HashSet<string>();
    }

    public virtual void InitHostConfig(HostConfig config) {}

    public virtual string GetNullableAppSetting(string key)
    {
        return null;
    }

    public virtual string GetAppSetting(string key)
    {
        return null;
    }

    public virtual string GetAppSetting(string key, string defaultValue)
    {
        return defaultValue;
    }

    public virtual T GetAppSetting<T>(string key, T defaultValue)
    {
        return defaultValue;
    }

    public virtual string GetConnectionString(string key)
    {
        return null;
    }

    public virtual string GetAppConfigPath()
    {
        return null;
    }

    public virtual Dictionary<string, string> GetCookiesAsDictionary(IRequest httpReq)
    {
        return new Dictionary<string, string>();
    }

    public virtual Dictionary<string, string> GetCookiesAsDictionary(IResponse httpRes)
    {
        return new Dictionary<string, string>();
    }

    /// <summary>
    /// Get the static Parse(string) method on the type supplied
    /// </summary>
    private static MethodInfo GetParseMethod(Type type)
    {
        const string parseMethod = "Parse";
        if (type == typeof(string))
            return typeof(ConfigUtils).GetMethod(parseMethod, BindingFlags.Public | BindingFlags.Static);

        var parseMethodInfo = type.GetStaticMethod(parseMethod, new[] { typeof(string) });
        return parseMethodInfo;
    }

    /// <summary>
    /// Gets the constructor info for T(string) if exists.
    /// </summary>
    private static ConstructorInfo GetConstructorInfo(Type type)
    {
        foreach (var ci in type.GetConstructors())
        {
            var ciTypes = ci.GetGenericArguments();
            var matchFound = (ciTypes.Length == 1 && ciTypes[0] == typeof(string)); //e.g. T(string)
            if (matchFound)
                return ci;
        }
        return null;
    }

    /// <summary>
    /// Returns the value returned by the 'T.Parse(string)' method if exists otherwise 'new T(string)'. 
    /// e.g. if T was a TimeSpan it will return TimeSpan.Parse(textValue).
    /// If there is no Parse Method it will attempt to create a new instance of the destined type
    /// </summary>
    public static T ParseTextValue<T>(string textValue)
    {
        var parseMethod = GetParseMethod(typeof(T));
        if (parseMethod == null)
        {
            var ci = GetConstructorInfo(typeof(T));
            if (ci == null)
                throw new TypeLoadException(
                    $"Error creating type {typeof(T).GetOperationName()} from text '{textValue}");

            var newT = ci.Invoke(null, new object[] { textValue });
            return (T)newT;
        }
        var value = parseMethod.Invoke(null, new object[] { textValue });
        return (T)value;
    }
}