getmd.go

package main

import (
	"bytes"
	"flag"
	"io/fs"
	"log"
	"os"
	"path/filepath"
	"strings"
)

func main() {
	flag.Parse()
	var sect string
	switch flag.NArg() {
	case 0:
	case 1:
		sect = flag.Arg(0)
	default:
		log.Fatalf("Too many arguments provided. Usage: getmd [section]")
	}

	home, err := os.UserHomeDir()
	if err != nil {
		log.Fatalf("Failed to get home directory: %v")
	}
	downloads := filepath.Join(home, "Downloads")
	des, err := os.ReadDir(downloads)
	if err != nil {
		log.Fatal(err)
	}
	var recent fs.DirEntry
	var recentInfo fs.FileInfo
	for _, de := range des {
		if !strings.HasSuffix(de.Name(), ".md") {
			continue
		}
		fi, err := de.Info()
		if err != nil {
			continue
		}
		if !fi.Mode().IsRegular() {
			continue
		}
		if recent == nil || fi.ModTime().After(recentInfo.ModTime()) {
			recent = de
			recentInfo = fi
		}
	}
	if recent == nil {
		log.Println("No *.md files found in Downloads.")
		return
	}
	contents, err := os.ReadFile(filepath.Join(downloads, recent.Name()))
	if err != nil {
		log.Fatalf("Failed to read file %s: %v", recent.Name(), err)
	}

	if sect != "" {
		var out bytes.Buffer
		var in bool
		start := `\<` + sect + `\>`
		end := `\</` + sect + `\>`
		for _, line := range strings.Split(string(contents), "\n") {
			if !in {
				in = strings.TrimSpace(line) == start
				continue
			}
			if strings.TrimSpace(line) == end {
				break
			}
			out.WriteString(line)
			out.WriteString("\n")
		}
		contents = out.Bytes()
	}

	os.Stdout.Write(contents)
}