146 lines
3.0 KiB
Go
146 lines
3.0 KiB
Go
package common
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import (
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"bufio"
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"errors"
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"fmt"
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"log"
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"os"
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"strings"
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)
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type Query struct {
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Search string
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Artist string
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Album string
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Song string
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}
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const emptyChar = ' '
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const songChar = 's'
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const albumChar = 'r'
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const artistChar = 'a'
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func NewQuery(search string) (Query, error) {
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search = strings.TrimSpace(search)
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query := Query{
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Search: search,
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}
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if search == "" {
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return query, errors.New("search should not be empty")
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}
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parsed := make(map[rune]string)
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indexChar := emptyChar
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nextIsIndex := false
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ignoreNextIfSpace := false
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for _, char := range search {
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// figuring out when the next char is an index char
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if char == '#' {
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// escape # => asserts previous char was also #
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if nextIsIndex {
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nextIsIndex = false
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parsed[indexChar] = parsed[indexChar] + "#"
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continue
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}
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nextIsIndex = true
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continue
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}
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// setting an index char
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if nextIsIndex {
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if char != songChar && char != albumChar && char != artistChar {
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return query, errors.New("the char after # has to be " + string(songChar) + ", " + string(albumChar) + " or " + string(artistChar) + " if it isn't escaped with another #")
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}
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if _, ok := parsed[char]; ok {
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return query, errors.New("you can use #" + string(char) + " only once")
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}
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indexChar = char
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nextIsIndex = false
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ignoreNextIfSpace = true
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parsed[char] = ""
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continue
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}
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if ignoreNextIfSpace {
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ignoreNextIfSpace = false
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if char == ' ' {
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continue
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}
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}
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parsed[indexChar] = parsed[indexChar] + string(char)
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}
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if nextIsIndex {
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return query, errors.New("there cant be an unescaped # at the end, it has to be escaped with another #")
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}
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if _, ok := parsed[emptyChar]; ok {
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// no other index char should be used
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e := errors.New("if you use advanced search with # you cant put anything before the first #")
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if _, ok := parsed[songChar]; ok {
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return query, e
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}
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if _, ok := parsed[albumChar]; ok {
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return query, e
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}
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if _, ok := parsed[artistChar]; ok {
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return query, e
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}
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query.Search = parsed[emptyChar]
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} else {
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query.Song = strings.TrimSpace(parsed[songChar])
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query.Album = strings.TrimSpace(parsed[albumChar])
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query.Artist = strings.TrimSpace(parsed[artistChar])
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elements := []string{}
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if query.Song != "" {
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elements = append(elements, query.Song)
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}
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if query.Artist != "" {
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elements = append(elements, query.Artist)
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}
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if query.Album != "" && len(elements) <= 1 {
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elements = append(elements, query.Album)
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}
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query.Search = strings.Join(elements, " - ")
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}
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return query, nil
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}
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func TestQueryParsing() {
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for {
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fmt.Print("> ")
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reader := bufio.NewReader(os.Stdin)
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line, err := reader.ReadString('\n')
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if err != nil {
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log.Fatal(err)
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return
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}
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query, err := NewQuery(line)
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if err != nil {
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fmt.Println(err)
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}
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fmt.Println("search: '" + query.Search + "'")
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fmt.Println("artist: '" + query.Artist + "'")
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fmt.Println("album: '" + query.Album + "'")
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fmt.Println("song: '" + query.Song + "'")
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fmt.Println()
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}
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}
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