// 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.Collections.Generic;
using Microsoft.Build.Shared;

#nullable disable

namespace Microsoft.Build.Utilities;

/// <summary>
/// Structure to represent an extension sdk
/// </summary>
internal class ExtensionSDK
{
    /// <summary>
    /// Path to the platform sdk may be null if not a platform sdk.
    /// </summary>
    private readonly string _path;

    /// <summary>
    /// Extension SDK moniker
    /// </summary>
    private readonly string _sdkMoniker;

    /// <summary>
    /// SDK version
    /// </summary>
    private Version _sdkVersion;

    /// <summary>
    /// SDK identifier
    /// </summary>
    private string _sdkIdentifier;

    /// <summary>
    /// Object containing the properties in the SDK manifest
    /// </summary>
    private SDKManifest _manifest;

    /// <summary>
    /// Caches minimum Visual Studio version from the manifest
    /// </summary>
    private Version _minVSVersion;

    /// <summary>
    /// Caches max platform version from the manifest
    /// </summary>
    private Version _maxPlatformVersion;

    /// <summary>
    /// Constructor
    /// </summary>
    public ExtensionSDK(string extensionSdkMoniker, string extensionSdkPath)
    {
        _sdkMoniker = extensionSdkMoniker;
        _path = extensionSdkPath;
    }

    /// <summary>
    /// SDK version from the moniker
    /// </summary>
    public Version Version
    {
        get
        {
            if (_sdkVersion == null)
            {
                ParseMoniker(_sdkMoniker);
            }

            return _sdkVersion;
        }
    }

    /// <summary>
    /// SDK identifier from the moniker
    /// </summary>
    public string Identifier
    {
        get
        {
            if (_sdkIdentifier == null)
            {
                ParseMoniker(_sdkMoniker);
            }

            return _sdkIdentifier;
        }
    }

    /// <summary>
    /// The type of the SDK.
    /// </summary>
    public SDKType SDKType => Manifest.SDKType;

    /// <summary>
    /// Minimum Visual Studio version from SDKManifest.xml
    /// </summary>
    public Version MinVSVersion
    {
        get
        {
            if (_minVSVersion == null && Manifest.MinVSVersion != null)
            {
                if (!Version.TryParse(Manifest.MinVSVersion, out _minVSVersion))
                {
                    _minVSVersion = null;
                }
            }

            return _minVSVersion;
        }
    }

    /// <summary>
    /// Maximum platform version from SDKManifest.xml
    /// </summary>
    public Version MaxPlatformVersion
    {
        get
        {
            if (_maxPlatformVersion == null && Manifest.MaxPlatformVersion != null)
            {
                if (!Version.TryParse(Manifest.MaxPlatformVersion, out _maxPlatformVersion))
                {
                    _maxPlatformVersion = null;
                }
            }

            return _maxPlatformVersion;
        }
    }

    /// <summary>
    /// Api contracts from the SDKManifest, if any
    /// </summary>
    public ICollection<ApiContract> ApiContracts => Manifest.ApiContracts;

    /// <summary>
    /// Reference to the manifest object
    /// Makes sure manifest is instantiated only once
    /// </summary>
    /// <remarks>Load manifest from disk the first time it is needed</remarks>
    private SDKManifest Manifest => _manifest ?? (_manifest = new SDKManifest(_path));

    /// <summary>
    /// Parse SDK moniker
    /// </summary>
    private void ParseMoniker(string moniker)
    {
        string[] properties = moniker.Split(MSBuildConstants.CommaChar);

        foreach (string property in properties)
        {
            string[] words = property.Split(MSBuildConstants.EqualsChar);

            if (words[0].Trim().StartsWith("Version", StringComparison.OrdinalIgnoreCase))
            {
                if (words.Length > 1 && Version.TryParse(words[1], out Version ver))
                {
                    _sdkVersion = ver;
                }
            }
            else
            {
                _sdkIdentifier = words[0];
            }
        }
    }
}