package parsekit

import (
	"fmt"
	"strings"
)

// Emit passes a Parser item to the client, including the provided string.
func (p *P) Emit(t ItemType, s string) {
	p.items <- Item{t, s}
	p.buffer.reset()
}

// EmitLiteral passes a Parser item to the client, including the accumulated
// string buffer data as a literal string.
func (p *P) EmitLiteral(t ItemType) {
	p.Emit(t, p.buffer.asLiteralString())
}

// EmitLiteralTrim passes a Parser item to the client, including the
// accumulated string buffer data as a literal string with whitespace
// trimmed from it.
func (p *P) EmitLiteralTrim(t ItemType) {
	p.Emit(t, strings.TrimSpace(p.buffer.asLiteralString()))
}

// EmitInterpreted passes a Parser item to the client, including the
// accumulated string buffer data a Go doubled quoted interpreted string
// (handling escape codes like \n, \t, \uXXXX, etc.)
// This method might return an error, in case there is data in the
// string buffer that is not valid for string interpretation.
func (p *P) EmitInterpreted(t ItemType) error {
	s, err := p.buffer.asInterpretedString()
	if err != nil {
		return err
	}
	p.Emit(t, s)
	return nil
}

// EmitError emits a Parser error item to the client.
func (p *P) EmitError(format string, args ...interface{}) {
	message := fmt.Sprintf(format, args...)
	p.Emit(ItemError, message)
}

// UnexpectedInput is used by a parser implementation to emit an
// error item that tells the client that an unexpected rune was
// encountered in the input.
func (p *P) UnexpectedInput() {
	r, _, ok := p.peek(0)
	switch {
	case ok:
		p.EmitError("unexpected character %q%s", r, p.fmtExpects())
	case r == EOF:
		p.EmitError("unexpected end of file%s", p.fmtExpects())
	case r == INVALID:
		p.EmitError("invalid UTF8 character in input%s", p.fmtExpects())
	default:
		panic("Unhandled output from peek()")
	}
}

func (p *P) fmtExpects() string {
	if p.expecting == "" {
		return ""
	}
	return fmt.Sprintf(" (expected %s)", p.expecting)
}