using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using AmazonInternal.ThirdParty;
using UnityEngine;
public class AmazonUtils {

    /// <summary>
    /// Compares two versions to see which is greater.
    /// </summary>
    /// <param name="a">Version to compare against second param</param>
    /// <param name="b">Version to compare against first param</param>
    /// <returns>-1 if the first version is smaller, 1 if the first version is greater, 0 if they are equal</returns>
    public static int CompareVersions (string a, string b) {
        var versionA = VersionStringToInts (a);
        var versionB = VersionStringToInts (b);
        for (var i = 0; i < Mathf.Max (versionA.Length, versionB.Length); i++) {
            if (VersionPiece (versionA, i) < VersionPiece (versionB, i))
                return -1;
            if (VersionPiece (versionA, i) > VersionPiece (versionB, i))
                return 1;
        }

        return 0;
    }

    private static int VersionPiece (IList<int> versionInts, int pieceIndex) {
        return pieceIndex < versionInts.Count ? versionInts[pieceIndex] : 0;
    }

    private static int[] VersionStringToInts (string version) {
        if( version == null )
        return new int[] { 0,0,0 };
        int piece;
        string[] split = version.Split ('.');
        return split.Select (v => int.TryParse (v, NumberStyles.Any, CultureInfo.InvariantCulture, out piece) ? piece : 0).ToArray ();
    }

    public static Uri UrlFromString (string url) {
        if (string.IsNullOrEmpty (url)) return null;
        try {
            return new Uri (url);
        } catch {
            Debug.LogError ("Invalid URL: " + url);
            return null;
        }
    }

    public static string EncodeArgs (params string[] args) {
        return Json.Serialize (args);
    }

    // Will return a non-null array of strings with at least 'min' non-null string values at the front.
    public static string[] DecodeArgs (string argsJson, int min) {
        var err = false;
        var args = Json.Deserialize (argsJson) as List<object>;
        if (args == null) {
            Debug.LogError ("Invalid JSON data: " + argsJson);
            args = new List<object> ();
            err = true;
        }
        if (args.Count < min) {
            if (!err) // Don't double up the error messages for invalid JSON
                Debug.LogError ("Missing one or more values: " + argsJson + " (expected " + min + ")");
            while (args.Count < min)
                args.Add ("");
        }
        return args.Select (v => v.ToString ()).ToArray ();
    }

    public static string InvariantCultureToString (object obj) {
        return string.Format (CultureInfo.InvariantCulture, "{0}", obj);
    }
}