s0rg/fantasyname

package wrappers

import (
    "fmt"
)

type collapser struct {
    s fmt.Stringer
}

// Collapsed creates wrapper that colapses similar runes triples (and some doubles) in its input.
func Collapsed(s fmt.Stringer) fmt.Stringer {
    return &collapser{s: s}
}

func (cl *collapser) String() string {
    var (
        max, cnt  int
        cur, prev rune
        rres      = []rune(cl.s.String())
        rout      = make([]rune, 0, len(rres))
    )

    for i := 0; i < len(rres); i++ {
        if cur = rres[i]; cur == prev {
            cnt++
        } else {
            cnt = 0
        }

        max = 2

        if needCollapse(cur) {
            max = 1
        }

        if cnt < max {
            rout = append(rout, cur)
        }

        prev = cur
    }

    return string(rout)
}

func needCollapse(r rune) (yes bool) {
    switch r {
    case 'a', 'i', 'u', 'y':
        return true
    case 'h', 'j', 'q', 'v', 'w', 'x':
        return true
    }

    return false
}