//go:build linux

package memory

import (
	"bufio"
	"fmt"
	"os"
	"regexp"
	"strconv"
	"strings"
)

var numberRegex *regexp.Regexp = regexp.MustCompile(`\d+`)

func getLinuxRamInfo() (MemoryInformation, error) {
	memoryFile, err := os.Open("/proc/meminfo")
	if err != nil {
		return MemoryInformation{}, fmt.Errorf("Could not find /proc/meminfo. Are you sure you are on linux?")
	}
	defer memoryFile.Close()

	fileReader := bufio.NewScanner(memoryFile)

	var TotalMemory uint64
	var AvailMemory uint64

	for fileReader.Scan() {
		line := fileReader.Text()

		if strings.HasPrefix(line, "MemTotal:") {
			TotalMemory, err = strconv.ParseUint(numberRegex.FindString(line), 10, 64)
			if err != nil {
				return MemoryInformation{}, fmt.Errorf("Could not parse total memory from /proc/meminfo")
			}
		} else if strings.HasPrefix(line, "MemAvailable:") {
			AvailMemory, err = strconv.ParseUint(numberRegex.FindString(line), 10, 64)
			if err != nil {
				return MemoryInformation{}, fmt.Errorf("Could not parse available memory from /proc/meminfo")
			}
		}

		if TotalMemory > 0 && AvailMemory > 0 {
			break
		}
	}

	if fileReader.Err() != nil {
		return MemoryInformation{}, fmt.Errorf("There was an error while reading /proc/meninfo. Error: %v", fileReader.Err())
	}

	return MemoryInformation{
		SystemMemory:    TotalMemory * 1024,
		AvailableMemory: AvailMemory * 1024,
	}, nil
}

func GetRamInformation() (MemoryInformation, error) {
	return getLinuxRamInfo()
}