// 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.Linq;
using System.Threading.Tasks;
using Microsoft.DotNet.Openapi.Tools;
using Microsoft.Extensions.CommandLineUtils;
using Microsoft.Extensions.Tools.Internal;

namespace Microsoft.DotNet.OpenApi.Commands
{
    internal class AddFileCommand : BaseCommand
    {
        private const string CommandName = "file";

        private const string SourceFileArgName = "source-file";

        public AddFileCommand(AddCommand parent, IHttpClientWrapper httpClient)
            : base(parent, CommandName, httpClient)
        {
            _codeGeneratorOption = Option("-c|--code-generator", "The code generator to use. Defaults to 'NSwagCSharp'.", CommandOptionType.SingleValue);
            _sourceFileArg = Argument(SourceFileArgName, $"The OpenAPI file to add. This must be a path to local OpenAPI file(s)", multipleValues: true);
        }

        internal readonly CommandArgument _sourceFileArg;
        internal readonly CommandOption _codeGeneratorOption;

        private readonly string[] ApprovedExtensions = new[] { ".json", ".yaml", ".yml" };

        protected override async Task<int> ExecuteCoreAsync()
        {
            var projectFilePath = ResolveProjectFile(ProjectFileOption);

            Ensure.NotNullOrEmpty(_sourceFileArg.Value, SourceFileArgName);
            var codeGenerator = GetCodeGenerator(_codeGeneratorOption);

            foreach (var sourceFile in _sourceFileArg.Values)
            {
                if (!ApprovedExtensions.Any(e => sourceFile.EndsWith(e, StringComparison.Ordinal)))
                {
                    await Warning.WriteLineAsync($"The extension for the given file '{sourceFile}' should have been one of: {string.Join(",", ApprovedExtensions)}.");
                    await Warning.WriteLineAsync($"The reference has been added, but may fail at build-time if the format is not correct.");
                }
                await AddOpenAPIReference(OpenApiReference, projectFilePath, sourceFile, codeGenerator);
            }

            return 0;
        }

        private bool IsLocalFile(string file)
        {
            return File.Exists(GetFullPath(file));
        }

        protected override bool ValidateArguments()
        {
            ValidateCodeGenerator(_codeGeneratorOption);

            try
            {
                Ensure.NotNullOrEmpty(_sourceFileArg.Value, SourceFileArgName);
            }
            catch(ArgumentException ex)
            {
                Error.Write(ex.Message);
                return false;
            }

            foreach (var sourceFile in _sourceFileArg.Values)
            {
                if (!IsLocalFile(sourceFile))
                {
                    Error.Write($"{SourceFileArgName} of '{sourceFile}' could not be found.");
                }
            }
            return true;
        }
    }
}
