package wikilink

import (
	"strings"
)

func isOpenLink(s string) bool {
	return strings.HasPrefix(s, OpenLink)
}

func isCloseLink(s string) bool {
	return strings.HasPrefix(s, CloseLink)
}

func isAlias(s string) bool {
	return strings.HasPrefix(s, Alias)
}

func isHeading(s string) bool {
	return strings.HasPrefix(s, Heading)
}

func isBlockRef(s string) bool {
	return strings.HasPrefix(s, BlockRef)
}

func lexIdent(l *Lexer) stateFn {
	for {
		r := l.next()
		s := l.input[l.pos:]
		if r == '\\' { // i think this will handle escape characters?
			break
		}
		switch {
		case isBlockRef(s):
			l.emit(ItemIdent)
			return lexBlockRef
		case isAlias(s):
			l.emit(ItemIdent)
			return lexAlias
		case isCloseLink(s):
			l.emit(ItemIdent)
			return lexCloseLink
		case isHeading(s):
			l.emit(ItemIdent)
			return lexHeading

		}
	}
	panic("we shouldn't be here")
	return nil // this shouldn't ever be reached
}

func lexHeading(l *Lexer) stateFn {
	l.pos += len(Heading)
	l.emit(ItemHeading)

	return lexIdent
}

func lexBlockRef(l *Lexer) stateFn {
	l.pos += len(BlockRef)
	l.emit(ItemBlockRef)

	return lexIdent
}

func lexAlias(l *Lexer) stateFn {
	l.pos += len(Alias)
	l.emit(ItemAlias)

	return lexIdent
}

func lexText(l *Lexer) stateFn {
	for {
		if isOpenLink(l.input[l.pos:]) {
			return lexOpenLink
		}
		r := l.next()
		switch {
		case r == EOF || r == '\n':
			l.emit(ItemText)
			return nil
		}
	}
}

func lexOpenLink(l *Lexer) stateFn {
	l.pos += len(OpenLink)
	l.emit(ItemOpenLink)

	return lexIdent
}

func lexCloseLink(l *Lexer) stateFn {
	l.pos += len(CloseLink)
	l.emit(ItemCloseLink)

	return lexText
}

/*
func lexInsideLink(l *Lexer) stateFn {
	log.Println("entering lexInsideLink")

	for {
		if strings.HasPrefix(l.input[l.pos:], CloseLink) {
			return lexCloseLink
		}

		r := l.next()
		log.Printf("inspecting %q\n", string(r))

		switch {
		case r == EOF:
		case r == '\n':
			return l.errorf("unclosed link")
		case r == '#':
			l.emit(ItemText)
			if l.peek() = '^' { return lexBlockRef }

			return lexHeading
		case r == '|':
			l.emit(ItemText)

			return lexAlias
		}
	}
}


*/