omissis/go-jsonschema

package codegen

import (
    "fmt"
    "strings"

    "github.com/mitchellh/go-wordwrap"
)

type Emitter struct {
    sb            strings.Builder
    maxLineLength uint
    start         bool
    indent        uint
}

func NewEmitter(maxLineLength uint) *Emitter {
    return &Emitter{
        maxLineLength: maxLineLength,
        start:         true,
    }
}

func (e *Emitter) String() string {
    return e.sb.String()
}

func (e *Emitter) Bytes() []byte {
    return []byte(e.sb.String())
}

func (e *Emitter) Indent(n int) {
    if int(e.indent)+n < 0 {
        panic("unexpected unbalanced indentation")
    }

    e.indent += uint(n)
}

func (e *Emitter) Comment(s string) {
    if s != "" {
        limit := e.maxLineLength - e.indent
        lines := strings.Split(wordwrap.WrapString(s, limit), "\n")

        for _, line := range lines {
            e.Printlnf("// %s", line)
        }
    }
}

func (e *Emitter) Commentf(s string, args ...interface{}) {
    s = fmt.Sprintf(s, args...)
    if s != "" {
        limit := e.maxLineLength - e.indent
        lines := strings.Split(wordwrap.WrapString(s, limit), "\n")

        for _, line := range lines {
            e.Printlnf("// %s", line)
        }
    }
}

func (e *Emitter) Printf(format string, args ...interface{}) {
    e.checkIndent()
    fmt.Fprintf(&e.sb, format, args...)
    e.start = false
}

func (e *Emitter) Printlnf(format string, args ...interface{}) {
    e.Printf(format, args...)
    e.Newline()
}

func (e *Emitter) Newline() {
    e.sb.WriteRune('\n')
    e.start = true
}

func (e *Emitter) checkIndent() {
    if e.start {
        for range e.indent {
            e.sb.WriteRune('\t')
        }

        e.start = false
    }
}

func (e *Emitter) MaxLineLength() uint {
    return e.maxLineLength
}