package parser

import (
	"asciigoat.org/core/lexer"
)

// AcceptQuotedString consumes a quoted string from the source
// and returns it unquoted.
func (p *TextParser) AcceptQuotedString() (string, bool, error) {
	r, _, err := p.ReadRune()
	switch {
	case err != nil:
		// nothing here
		return "", false, err
	case r != RuneQuotes:
		// not for us
		p.UnreadRune()
		return "", false, nil
	default:
		// let's roll
		s, err := lexQuotedString(p)
		switch {
		case err != nil:
			// bad quoted string
			return "", false, err
		default:
			// success
			return s, true, nil
		}
	}
}

func lexQuotedString(p *TextParser) (string, *lexer.Error) {
	s, ok, err := lexQuotedStringNoEscape(p)
	switch {
	case err != nil:
		return "", err
	case ok:
		return s, nil
	default:
		// escape character detected
		return lexQuotedStringEscaped(p)
	}
}

func lexQuotedStringNoEscape(p *TextParser) (string, bool, *lexer.Error) {
	for {
		r, _, err := p.ReadRune()
		switch {
		case err != nil:
			// incomplete
			return "", false, NewErrIncompleteQuotedString(p)
		case r == RuneQuotes:
			// end, just remove the quotes
			s := p.String()
			l := len(s)
			return s[1 : l-2], true, nil
		case r == RuneEscape:
			// things just got complicated...
			return "", false, nil
		case IsNewLine(r):
			// new lines within quoted values are acceptable
			p.UnreadRune()
			p.AcceptNewLine()
		default:
			// continue
		}
	}
}

func lexQuotedStringEscaped(*TextParser) (string, *lexer.Error) {
	panic("not implemented")
}

// Unquoted removes quotes and unescapes the content
func Unquoted(s string) (string, error) {
	var p TextParser
	if s == "" {
		return "", nil
	}

	p.InitString(s)
	unquoted, ok, err := p.AcceptQuotedString()
	switch {
	case err != nil:
		// bad string
		return "", err
	case ok:
		// success
		return unquoted, nil
	default:
		// not quoted
		return s, nil
	}
}