/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuSWInfo.Linux.cpp
    Date: 2022-4-6
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuSWInfo.hpp"
#include "AuSWInfo.Linux.hpp"

namespace Aurora::SWInfo
{
    static AuString gKernelString;
    static AuString gUserlandBrand;
    static AuString gUserlandDesktopEnv;
    static AuString gBuildString;

    static void SetProcVersion()
    {
        AuIOFS::ReadString("/proc/version", gBuildString);
        if (gBuildString.size() && gBuildString[gBuildString.size() - 1] == '\n')
        {
            gBuildString.pop_back();
        }
    }

    static void SetVersion(OSInformation &osInfo)
    {
        char *endPtr;

        auto versionItr = gBuildString.find("ersion ");
        if (versionItr == AuString::npos) return;

        if (versionItr > 2)
        {
            gKernelString = gBuildString.substr(0, versionItr - 2);
        }
            
        auto ptr = gBuildString.c_str() + (7 + AuUInt(versionItr));

        osInfo.uKernelMajor = strtoll(ptr, &endPtr, 10);
        if (errno == ERANGE) return;
        if (*endPtr != '.') return;

        endPtr++;

        osInfo.uKernelMinor = strtoll(endPtr, &endPtr, 10);
        if (errno == ERANGE) return;
        if (*endPtr != '.') return;

        endPtr++;

        osInfo.uKernelPatch = strtoll(endPtr, &endPtr, 10);
    }

    static bool ProcessVersionLine(OSInformation &osInfo,const AuString &line);

    static void ParseOSRel(OSInformation &osInfo)
    {
        AuString osRel;

        if (!AuIOFS::ReadString("/etc/os-release", osRel))
        {
            if (!AuIOFS::ReadString("/usr/lib/os-release", osRel))
            {
                return;
            }
        }

        AuReplaceAll(osRel, "\"", "");

        AuList<AuString> versionNumbers;

        Parse::SplitNewlines(osRel, [&](const AuString &line)
        {
            if (AuStartsWith(line, "NAME="))
            {
                gUserlandBrand = line.substr(5);
            }
            else if (AuStartsWith(line, "VERSION="))
            {
                versionNumbers.push_back(line.substr(8));
            }
            else if (AuStartsWith(line, "VERSION_ID="))
            {
                versionNumbers.push_back(line.substr(11));
            }
            else if (AuStartsWith(line, "BUILD_ID="))
            {
                versionNumbers.push_back(line.substr(9));
            }
        });

        for (const auto &line : versionNumbers)
        {
            if (ProcessVersionLine(osInfo, line))
            {
                break;
            }
        }
    }

    static bool ProcessVersionLineParts(OSInformation &osInfo, const AuString &line)
    {
        auto firstPeriod = line.find(".");
        if (firstPeriod == AuString::npos)
        {
            return false;
        }

        auto ptr = line.data();
        char *endPtr = (char *)line.c_str() + line.size();

        osInfo.uUserlandMajor = strtoll(ptr, &endPtr, 10);
        if (errno == ERANGE) return false;
        if (*endPtr != '.') return true;

        endPtr++;

        osInfo.uUserlandMinor = strtoll(endPtr, &endPtr, 10);
        if (errno == ERANGE) return false;
        if (*endPtr != '.') return true;

        endPtr++;

        osInfo.uUserlandPatch = strtoll(endPtr, &endPtr, 10);
        return true;
    }

    static bool ProcessVersionLine(OSInformation &osInfo, const AuString &line)
    {
        auto parts = AuSplitString(line, " ");

        for (const auto &line : parts)
        {
            if (ProcessVersionLineParts(osInfo, line))
            {
                return true;
            }
        }
        
        return false;
    }

    static void SetDesktopWindowManager()
    {
        const char *name;

        name = ::getenv("XDG_CURRENT_DESKTOP");

        if (!name)
        {
            name = ::getenv("XDG_SESSION_DESKTOP");
        }
        
        if (!name)
        {
            name = ::getenv("DESKTOP_SESSION");
        }

        if (name)
        {
            gUserlandDesktopEnv = name;
        }
    }

    static void CheckForSupportLicenseHints(OSInformation &osInfo)
    {
        AuString a;
        
        osInfo.bIsEnterprise = false;

        // redhat
        if (AuFS::ReadString("/etc/system-release-cpe", a))
        {
            osInfo.bIsEnterprise |= a.find("nterprise") != AuString::npos; // cpe:?????:enterprise_linux:??????
        }
    }

    void InitLinuxInfo(OSInformation &osInfo)
    {
        osInfo = AuMove(OSInformation(&gKernelString, &gUserlandBrand, &gUserlandDesktopEnv, &gBuildString, Aurora::Build::EPlatform::eEnumInvalid));

        SetProcVersion();
        SetVersion(osInfo);
        ParseOSRel(osInfo);
        CheckForSupportLicenseHints(osInfo);

        SetDesktopWindowManager();
    }
}