main.go

package main

import (
	"bytes"
	"encoding/csv"
	"log"
	"math/rand"
	"os"
	"time"
)

type C struct {
	NextR rune
	Stop bool
}

var (
	m = []map[string][]C{}
	knownTitles = map[string]struct{}{}
)

func addWeight(pos int, preceding string, cur rune, stop bool) {
	for pos >= len(m) {
		m = append(m, map[string][]C{})
	}
	v, ok := m[pos][preceding]
	if !ok {
		v = []C{}
	}
	m[pos][preceding] = append(v, C{NextR: cur, Stop: stop})
}

func getOneWeight(pos int, preceding string) (rune, bool) {
	if pos >= len(m) {
		return '.', false
	}
	v, ok := m[pos][preceding]
	if !ok {
		return '.', false
	}
	if len(v) == 0 {
		return '.', false
	}
	c := v[rand.Int31n(int32(len(v)))]
	return c.NextR, c.Stop
}

func addToChain(title string) {
	t := bytes.Runes([]byte(title))
	for i := 0; i < len(t); i++ {
		s := i - 3
		if s < 0 {
			s = 0
		}
		p := string(t[s:i])
		addWeight(i, p, t[i], i == len(t) - 1)
	}
}

func main() {
	rand.Seed(time.Now().UnixNano())
	log.SetFlags(log.Lshortfile|log.Flags())
	f, err := os.Open("list.csv")
	if err != nil {
		log.Panic(err)
	}
	defer f.Close()
	cr := csv.NewReader(f)
	all, err := cr.ReadAll()
	if err != nil {
		log.Panic(err)
	}
	for _, row := range all {
		knownTitles[row[0]] = struct{}{}
		addToChain(row[0])
	}
	for i := 0; i < 26; i++ {
		log.Print(makeNewTitle())
	}
}

func makeNewTitle() string {
	for i := 0; i < 100; i++ {
		title := makeTitle()
		if _, ok := knownTitles[title]; !ok {
			return title
		}
	}
	log.Panic("Couldn't find new title!")
	return ""
}

func makeTitle() string {
	result := []rune{}
	stop := false
	for p:=0;!stop;p++ {
		s := p - 3
		if s < 0 {
			s = 0
		}
		k := string(result[s:p])
		r, b := getOneWeight(p, k)
		result = append(result, r)
		stop = b
	}
	return string(result)
}