um/sort/sort.go

104 lines
2.5 KiB
Go

package sort
import (
"errors"
"fmt"
"log"
"os"
"slices"
"strings"
"github.com/brtholomy/um/go/cmd"
"github.com/brtholomy/um/go/flags"
"github.com/brtholomy/um/go/pipe"
)
const (
CMD = cmd.Sort
SUMMARY = "sort a filelist using a provided key filelist"
)
type options struct {
Source flags.String
Key flags.String
Write flags.Bool
Help flags.Bool
}
func initOpts() options {
return options{
flags.String{"--source", "-s", "", "path to source list. reads from stdin if omitted."},
flags.String{"--key", "-k", "", "path to sort key"},
flags.Bool{"--write", "-w", false, "write sorted list back to --key file"},
flags.Bool{"--help", "-h", false, "show help"},
}
}
// record the order of the given filelist.
func kMap(kslice []string) map[string]int {
m := make(map[string]int, 0)
for i, l := range kslice {
m[l] = i
}
return m
}
// write out the provided source slice while respecting the order provided by kmap
func sort(sslice []string, kmap map[string]int) string {
oslice := make([]string, max(len(sslice), len(kmap))+1)
for _, l := range sslice {
// lines not represented in the key get appended to the end:
if _, ok := kmap[l]; !ok {
// we don't care that this might leave empty strings between:
oslice = append(oslice, l)
continue
}
// NOTE: raison d'etre of this whole thang:
// if present in the key, respect the order:
oslice[kmap[l]] = l
}
// delete empties and add a final newline
oslice = slices.DeleteFunc(oslice, func(e string) bool { return e == "" })
return strings.Join(oslice, pipe.Newline) + pipe.Newline
}
func write(file string, content string) {
if err := os.WriteFile(file, []byte(content), 0664); err != nil {
log.Fatalf("um %s: error writing file: %s\n%s", CMD, file, err)
}
}
func Sort(args []string) {
opts := initOpts()
help := flags.NewHelpError(CMD, SUMMARY)
if err := flags.ParseArgs(help, args, &opts); err != nil {
var herr flags.HelpError
if errors.As(err, &herr) {
fmt.Println(herr)
return
}
log.Fatalf("um %s: %s", CMD, err)
}
// BORK: by hand for now:
if !opts.Key.IsSet() {
fmt.Println(help.HelpRequired(opts.Key.Long))
return
}
sslice, err := pipe.FileListSplitMaybeStdin(opts.Source.Val)
if err != nil {
log.Fatalf("um %s: %s", CMD, err)
}
kslice, err := pipe.FileListSplit(opts.Key.Val)
if err != nil {
log.Fatalf("um %s: %s", CMD, err)
}
kmap := kMap(kslice)
out := sort(sslice, kmap)
if opts.Write.IsSet() {
write(opts.Key.Val, out)
} else {
// to stdout
fmt.Print(out)
}
}