// Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.

using System;
using System.IO;

namespace Flax.Build.Platforms
{
    /// <summary>
    /// The Linux build platform implementation.
    /// </summary>
    /// <seealso cref="Platform" />
    /// <seealso cref="UnixPlatform" />
    public class LinuxPlatform : UnixPlatform
    {
        /// <inheritdoc />
        public override TargetPlatform Target => TargetPlatform.Linux;

        /// <inheritdoc />
        public override bool HasRequiredSDKsInstalled { get; }

        /// <inheritdoc />
        public override bool HasSharedLibrarySupport => true;

        /// <summary>
        /// The toolchain folder root.
        /// </summary>
        public readonly string ToolchainRoot;

        /// <summary>
        /// True if use platform native system compiler instead of external package.
        /// </summary>
        public readonly bool UseSystemCompiler;

        /// <summary>
        /// Initializes a new instance of the <see cref="LinuxPlatform"/> class.
        /// </summary>
        public LinuxPlatform()
        {
            // Check if use system compiler
            if (Environment.OSVersion.Platform == PlatformID.Unix && Which("clang++-7") != null)
            {
                // Build toolchain root path
                ToolchainRoot = string.Empty;
                Log.Verbose("Using native Linux toolchain (system compiler)");
                HasRequiredSDKsInstalled = true;
                UseSystemCompiler = true;
            }
            else
            {
                // Check if Linux toolchain is installed
                string toolchainName = "v13_clang-7.0.1-centos7";
                string toolchainsRoot = Environment.GetEnvironmentVariable("LINUX_TOOLCHAINS_ROOT");
                if (string.IsNullOrEmpty(toolchainsRoot) || !Directory.Exists(Path.Combine(toolchainsRoot, toolchainName)))
                {
                    if (string.IsNullOrEmpty(toolchainsRoot))
                    {
                        Log.Warning("Missing Linux Toolchain. Cannot build for Linux platform.");
                    }

                    return;
                }

                // Build toolchain root path
                ToolchainRoot = Path.Combine(toolchainsRoot, toolchainName).Replace('\\', '/');
                Log.Verbose(string.Format("Found Linux Toolchain at {0}", ToolchainRoot));
                HasRequiredSDKsInstalled = true;
                UseSystemCompiler = false;
            }
        }

        /// <inheritdoc />
        protected override Toolchain CreateToolchain(TargetArchitecture architecture)
        {
            return new LinuxToolchain(this, architecture);
        }

        /// <inheritdoc />
        public override bool CanBuildPlatform(TargetPlatform platform)
        {
            switch (platform)
            {
            case TargetPlatform.Linux: return HasRequiredSDKsInstalled;
            case TargetPlatform.Android: return AndroidSdk.Instance.IsValid && AndroidNdk.Instance.IsValid;
            default: return false;
            }
        }
    }
}