// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.IO;
using System.Collections.Generic;

namespace Microsoft.DotNet.Build.Tasks.Packaging;

public class NuspecPropertyStringProvider
{
    public static Dictionary<string, string> GetNuspecPropertyDictionary(string[] nuspecProperties)
    {
        if (nuspecProperties == null)
        {
            return null;
        }

        var propertyDictionary = new Dictionary<string, string>();
        foreach (var propertyString in nuspecProperties)
        {
            var property = GetKeyValuePair(propertyString);
            propertyDictionary[property.Item1] = property.Item2;
        }

        return propertyDictionary;
    }

    public static Func<string, string> GetNuspecPropertyProviderFunction(string[] nuspecPropertyStrings)
    {
        var propertyDictionary = GetNuspecPropertyDictionary(nuspecPropertyStrings);

        if (propertyDictionary == null)
        {
            return null;
        }

        return k => propertyDictionary[k];
    }

    private static Tuple<string, string> GetKeyValuePair(string propertyString)
    {
        propertyString = propertyString.Trim();

        var indexOfEquals = propertyString.IndexOf("=", StringComparison.Ordinal);

        if (indexOfEquals == -1)
        {
            throw new InvalidDataException($"Nuspec property {propertyString} does not have an \'=\' character in it");
        }

        if (indexOfEquals == propertyString.Length - 1)
        {
            throw new InvalidDataException($"Nuspec property {propertyString} does not have a value");
        }

        if (indexOfEquals == 0)
        {
            throw new InvalidDataException($"Nuspec property {propertyString} does not have a key");
        }

        var key = propertyString.Substring(0, indexOfEquals);

        var valueStartIndex = indexOfEquals + 1;
        var valueLength = propertyString.Length - valueStartIndex;
        var value = propertyString.Substring(valueStartIndex, valueLength);

        return new Tuple<string, string>(key, value);
    }
}