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

using System.Text.Json.Nodes;

namespace Microsoft.TemplateEngine.Orchestrator.RunnableProjects.OperationConfig
{
    internal class ConditionalKeywords
    {
        private const string DefaultPrefix = "#";
        private static readonly IReadOnlyList<string> DefaultIfKeywords = new[] { "if" };
        private static readonly IReadOnlyList<string> DefaultElseIfKeywords = new[] { "elseif", "elif" };
        private static readonly IReadOnlyList<string> DefaultElseKeywords = new[] { "else" };
        private static readonly IReadOnlyList<string> DefaultEndIfKeywords = new[] { "endif" };

        internal ConditionalKeywords()
        {
            KeywordPrefix = DefaultPrefix;
            IfKeywords = DefaultIfKeywords;
            ElseIfKeywords = DefaultElseIfKeywords;
            ElseKeywords = DefaultElseKeywords;
            EndIfKeywords = DefaultEndIfKeywords;
        }

        internal string KeywordPrefix { get; set; }

        internal IReadOnlyList<string> IfKeywords { get; set; }

        internal IReadOnlyList<string> ElseIfKeywords { get; set; }

        internal IReadOnlyList<string> ElseKeywords { get; set; }

        internal IReadOnlyList<string> EndIfKeywords { get; set; }

        // TODO: Allow the rawConfiguration elements to be either strings (as-is) or arrays of strings.
        // The code that consumes instances of this class is already setup to deal with multiple forms of each keyword type.
        internal static ConditionalKeywords FromJObject(JsonObject rawConfiguration)
        {
            ConditionalKeywords keywords = new ConditionalKeywords();
            string? ifKeyword = rawConfiguration.ToString("ifKeyword");
            if (!string.IsNullOrWhiteSpace(ifKeyword))
            {
                keywords.IfKeywords = new[] { ifKeyword! };
            }

            string? elseIfKeyword = rawConfiguration.ToString("elseIfKeyword");
            if (!string.IsNullOrWhiteSpace(elseIfKeyword))
            {
                keywords.ElseIfKeywords = new[] { elseIfKeyword! };
            }

            string? elseKeyword = rawConfiguration.ToString("elseKeyword");
            if (!string.IsNullOrWhiteSpace(elseKeyword))
            {
                keywords.ElseKeywords = new[] { elseKeyword! };
            }

            string? endIfKeyword = rawConfiguration.ToString("endIfKeyword");
            if (!string.IsNullOrWhiteSpace(endIfKeyword))
            {
                keywords.EndIfKeywords = new[] { endIfKeyword! };
            }

            string? prefixString = rawConfiguration.ToString("keywordPrefix");
            if (prefixString != null)
            {
                // Empty string is a valid value for keywordPrefix, null is not.
                // If the "keywordPrefix" key isn't present in the config, the value will be null and not used.
                keywords.KeywordPrefix = prefixString;
            }

            return keywords;
        }
    }
}