package stat

import (
	"bufio"
	"io"
	"strings"
)

type MemStat struct {
}

func (mem MemStat) Command() string {
	return "cat /proc/meminfo"
}

func (mem MemStat) Read(r io.Reader, keys []string) (*map[string]string, error) {
	var (
		stats   = map[string]string{}
		scanner = bufio.NewScanner(r)
	)

	for scanner.Scan() {
		line := scanner.Text()
		parts := strings.Fields(line)
		key := parts[0][:len(parts[0])-1]

		stats[key] = parts[1]
	}

	res, err := mem.parse(keys, stats)
	if err != nil {
		return nil, err
	}

	return &res, scanner.Err()
}

func (mem MemStat) parse(keys []string, data map[string]string) (map[string]string, error) {
	resMap := make(map[string]string)

	for _, key := range keys  {
		switch key {
		case "mem.usage.total":
			resMap[key] = data["MemTotal"]
		case "mem.usage.free":
			resMap[key] = data["MemFree"]
		case "mem.usage.available":
			resMap[key] = data["MemAvailable"]
		case "mem.usage.buffers":
			resMap[key] = data["Buffers"]
		case "mem.usage.cached":
			resMap[key] = data["Cached"]
		case "mem.swap.usage.total":
			resMap[key] = data["SwapTotal"]
		case "mem.swap.usage.free":
			resMap[key] = data["SwapFree"]
		case "mem.swap.usage.cached":
			resMap[key] = data["SwapCached"]
		default:

		}
	}

	return resMap, nil
}