package parser

import (
	"strings"

	"asciigoat.org/core/lexer"
)

type commaArrayParser struct {
	TextParser

	out []string
}

func (p *commaArrayParser) lexStart() (lexer.StateFn, error) {
	for {
		r, _, err := p.ReadRune()
		switch {
		case err != nil:
			// EOF
			return nil, err
		case r == RuneQuotes:
			// Quoted Value
			return p.lexQuotedString, nil
		case IsNewLine(r):
			// new lines are acceptable when parsing a string for
			// comma delimited arrays. but make sure we discard it
			// complete
			p.UnreadRune()
			p.AcceptNewLine()
			p.Discard()
		case lexer.IsSpace(r):
			// discard whitespace outside quotes
			p.Discard()
		default:
			p.UnreadRune()
			return p.lexWord, nil
		}
	}
}

func (p *commaArrayParser) lexWord() (lexer.StateFn, error) {
	for {
		r, _, err := p.ReadRune()
		switch {
		case err != nil:
			// done. store what we got and move on
			_, s := p.Emit()
			p.out = append(p.out, s)
			return nil, err
		case r == ',':
			// done
			_, s := p.Emit()
			// remove comma, trim and append to output
			s = strings.TrimRightFunc(s[:len(s)-1], IsSpace)
			p.out = append(p.out, s)
			return p.lexStart, nil
		}
	}
}

func (p *commaArrayParser) lexQuotedString() (lexer.StateFn, error) {
	s, err := lexQuotedString(&p.TextParser)
	if err != nil {
		return nil, err
	}

	p.Discard()
	p.out = append(p.out, s)
	return p.lexStart, nil
}

func (p *commaArrayParser) Run() ([]string, error) {
	err := lexer.Run(p.lexStart)

	return p.out, err
}

// SplitCommaArray splits comma separated strings, removing whitespace
// and respecting quoted literals.
func SplitCommaArray(s string) ([]string, error) {
	if s != "" {
		var p commaArrayParser
		p.InitString(s)
		return p.Run()
	}
	return nil, nil
}