// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Microsoft.Build.Construction;
using Microsoft.Build.Evaluation;
using Microsoft.Build.Exceptions;
using Microsoft.DotNet.Cli.Utils;
using Microsoft.DotNet.Tools.Common;
using Microsoft.DotNet.Tools.ProjectExtensions;
using NuGet.Frameworks;

namespace Microsoft.DotNet.Tools
{
    internal class MsbuildProject
    {
        const string ProjectItemElementType = "ProjectReference";

        public ProjectRootElement ProjectRootElement { get; private set; }
        public string ProjectDirectory { get; private set; }

        private ProjectCollection _projects;
        private List<NuGetFramework> _cachedTfms = null;

        private MsbuildProject(ProjectCollection projects, ProjectRootElement project)
        {
            _projects = projects;
            ProjectRootElement = project;
            ProjectDirectory = PathUtility.EnsureTrailingSlash(ProjectRootElement.DirectoryPath);
        }

        public static MsbuildProject FromFileOrDirectory(ProjectCollection projects, string fileOrDirectory)
        {
            if (File.Exists(fileOrDirectory))
            {
                return FromFile(projects, fileOrDirectory);
            }
            else
            {
                return FromDirectory(projects, fileOrDirectory);
            }
        }

        public static MsbuildProject FromFile(ProjectCollection projects, string projectPath)
        {
            if (!File.Exists(projectPath))
            {
                throw new GracefulException(CommonLocalizableStrings.ProjectDoesNotExist, projectPath);
            }

            var project = TryOpenProject(projects, projectPath);
            if (project == null)
            {
                throw new GracefulException(CommonLocalizableStrings.ProjectIsInvalid, projectPath);
            }

            return new MsbuildProject(projects, project);
        }

        public static MsbuildProject FromDirectory(ProjectCollection projects, string projectDirectory)
        {
            FileInfo projectFile = GetProjectFileFromDirectory(projectDirectory);

            var project = TryOpenProject(projects, projectFile.FullName);
            if (project == null)
            {
                throw new GracefulException(CommonLocalizableStrings.FoundInvalidProject, projectFile.FullName);
            }

            return new MsbuildProject(projects, project);
        }

        public static FileInfo GetProjectFileFromDirectory(string projectDirectory)
        {
            DirectoryInfo dir;
            try
            {
                dir = new DirectoryInfo(projectDirectory);
            }
            catch (ArgumentException)
            {
                throw new GracefulException(CommonLocalizableStrings.CouldNotFindProjectOrDirectory, projectDirectory);
            }

            if (!dir.Exists)
            {
                throw new GracefulException(CommonLocalizableStrings.CouldNotFindProjectOrDirectory, projectDirectory);
            }

            FileInfo[] files = dir.GetFiles("*proj");
            if (files.Length == 0)
            {
                throw new GracefulException(
                    CommonLocalizableStrings.CouldNotFindAnyProjectInDirectory,
                    projectDirectory);
            }

            if (files.Length > 1)
            {
                throw new GracefulException(CommonLocalizableStrings.MoreThanOneProjectInDirectory, projectDirectory);
            }

            return files.First();
        }

        public int AddProjectToProjectReferences(string framework, IEnumerable<string> refs)
        {
            int numberOfAddedReferences = 0;

            ProjectItemGroupElement itemGroup = ProjectRootElement.FindUniformOrCreateItemGroupWithCondition(
                ProjectItemElementType,
                framework);
            foreach (var @ref in refs.Select((r) => PathUtility.GetPathWithBackSlashes(r)))
            {
                if (ProjectRootElement.HasExistingItemWithCondition(framework, @ref))
                {
                    Reporter.Output.WriteLine(string.Format(
                        CommonLocalizableStrings.ProjectAlreadyHasAreference,
                        @ref));
                    continue;
                }

                numberOfAddedReferences++;
                itemGroup.AppendChild(ProjectRootElement.CreateItemElement(ProjectItemElementType, @ref));

                Reporter.Output.WriteLine(string.Format(CommonLocalizableStrings.ReferenceAddedToTheProject, @ref));
            }

            return numberOfAddedReferences;
        }

        public int RemoveProjectToProjectReferences(string framework, IEnumerable<string> refs)
        {
            int totalNumberOfRemovedReferences = 0;

            foreach (var @ref in refs)
            {
                totalNumberOfRemovedReferences += RemoveProjectToProjectReferenceAlternatives(framework, @ref);
            }

            return totalNumberOfRemovedReferences;
        }

        public IEnumerable<ProjectItemElement> GetProjectToProjectReferences()
        {
            return ProjectRootElement.GetAllItemsWithElementType(ProjectItemElementType);
        }

        public IEnumerable<NuGetFramework> GetTargetFrameworks()
        {
            if (_cachedTfms != null)
            {
                return _cachedTfms;
            }

            var project = GetEvaluatedProject();
            _cachedTfms = project.GetTargetFrameworks().ToList();
            return _cachedTfms;
        }

        public bool CanWorkOnFramework(NuGetFramework framework)
        {
            foreach (var tfm in GetTargetFrameworks())
            {
                if (DefaultCompatibilityProvider.Instance.IsCompatible(framework, tfm))
                {
                    return true;
                }
            }

            return false;
        }

        public bool IsTargettingFramework(NuGetFramework framework)
        {
            foreach (var tfm in GetTargetFrameworks())
            {
                if (framework.Equals(tfm))
                {
                    return true;
                }
            }

            return false;
        }

        private Project GetEvaluatedProject()
        {
            try
            {
                return _projects.LoadProject(ProjectRootElement.FullPath);
            }
            catch (InvalidProjectFileException e)
            {
                throw new GracefulException(string.Format(
                    CommonLocalizableStrings.ProjectCouldNotBeEvaluated,
                    ProjectRootElement.FullPath, e.Message));
            }
        }

        private int RemoveProjectToProjectReferenceAlternatives(string framework, string reference)
        {
            int numberOfRemovedRefs = 0;
            foreach (var r in GetIncludeAlternativesForRemoval(reference))
            {
                foreach (var existingItem in ProjectRootElement.FindExistingItemsWithCondition(framework, r))
                {
                    ProjectElementContainer itemGroup = existingItem.Parent;
                    itemGroup.RemoveChild(existingItem);
                    if (itemGroup.Children.Count == 0)
                    {
                        itemGroup.Parent.RemoveChild(itemGroup);
                    }

                    numberOfRemovedRefs++;
                    Reporter.Output.WriteLine(string.Format(CommonLocalizableStrings.ProjectReferenceRemoved, r));
                }
            }

            if (numberOfRemovedRefs == 0)
            {
                Reporter.Output.WriteLine(string.Format(
                    CommonLocalizableStrings.ProjectReferenceCouldNotBeFound,
                    reference));
            }

            return numberOfRemovedRefs;
        }

        // Easiest way to explain rationale for this function is on the example. Let's consider following directory structure:
        // .../a/b/p.proj <project>
        // .../a/d/ref.proj <reference>
        // .../a/e/f/ <current working directory>
        // Project = /some/path/a/b/p.proj
        //
        // We do not know the format of passed reference so
        // path references to consider for removal are following:
        // - full path to ref.proj [/some/path/a/d/ref.proj]
        // - string which is passed as reference is relative to project [../d/ref.proj]
        // - string which is passed as reference is relative to current dir [../../d/ref.proj]
        private IEnumerable<string> GetIncludeAlternativesForRemoval(string reference)
        {
            // We do not care about duplicates in case when i.e. reference is already full path
            var ret = new List<string>();
            ret.Add(reference);

            string fullPath = Path.GetFullPath(reference);
            ret.Add(fullPath);
            ret.Add(PathUtility.GetRelativePath(ProjectDirectory, fullPath));

            return ret;
        }

        // There is ProjectRootElement.TryOpen but it does not work as expected
        // I.e. it returns null for some valid projects
        private static ProjectRootElement TryOpenProject(ProjectCollection projects, string filename)
        {
            try
            {
                return ProjectRootElement.Open(filename, projects, preserveFormatting: true);
            }
            catch (InvalidProjectFileException)
            {
                return null;
            }
        }
    }
}