// modbot is a system information agregator
// Copyright (C) 2024 frosty <inthishouseofcards@gmail.com>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package readers

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

type OsInfo struct {
	Name       string
	PrettyName string
	Version    string
}

func ReadOs() func() (interface{}, error) {
	return func() (interface{}, error) {
		const osPath = "/lib/os-release"

		file, err := os.Open(osPath)
		if err != nil {
			return OsInfo{}, fmt.Errorf("failed to open %s: %w", osPath, err)
		}
		defer file.Close()

		var osName, osPrettyName, osVersion string
		scanner := bufio.NewScanner(file)

		for scanner.Scan() {
			line := scanner.Text()
			line = strings.ReplaceAll(line, "\"", "")
			fields := strings.SplitN(line, "=", 2)

			if len(fields) < 2 {
				return OsInfo{}, fmt.Errorf("unexpected format in %s: %s", osPath, line)
			}

			switch {
			case strings.HasPrefix(line, "NAME"):
				osName = fields[1]
			case strings.HasPrefix(line, "PRETTY_NAME"):
				osPrettyName = fields[1]
			case strings.HasPrefix(line, "VERSION_ID"):
				osVersion = fields[1]
			}
		}

		if err := scanner.Err(); err != nil {
			return OsInfo{}, fmt.Errorf("failed to read from %s: %w", osPath, err)
		}

		return OsInfo{
			Name:       osName,
			PrettyName: osPrettyName,
			Version:    osVersion,
		}, nil
	}
}