package main

import (
	"regexp"
	"strings"
)

// Lexer embbed a temporary buffer to store "content"
// (url, description, tags) and an array of tokens
type Lexer struct {
	Buf    string
	Tokens []Token
}

func (l *Lexer) AddToken(t string, s string) {
	l.Tokens = append(l.Tokens, Token{t, s})
}

// Return last tokenized item, useful to determine context for a symbol
func (l Lexer) LastToken() Token {
	var lastToken Token
	if len(l.Tokens) > 0 {
		lastToken = l.Tokens[len(l.Tokens)-1]
	}
	return lastToken
}

func (l Lexer) CountToken(t string) int {
	var counter int
	for i := range l.Tokens {
		if l.Tokens[i].Value == t {
			counter ++
		}
	}
	return counter
}

func (l *Lexer) ProcessSimpleLink(s string) {
	ss := strings.Split(s[3:], " ")
	for w := range ss {
		if w == 0 {
			url := strings.TrimSpace(ss[w])
			l.AddToken("URL", url)
		} else {
			if ss[w] != "" && ss[w] != " " {
				tag := strings.ReplaceAll(ss[w], ":", "")
				l.AddToken("TAG", tag)
			}
		}
	}
}

// Tokenize a given line s from the org file
func (l Lexer) Process(s string) []Token {
	if s[3] != '[' {
		l.ProcessSimpleLink(s)
		return l.Tokens
	}

	re := regexp.MustCompile(`(?:\[\[)(?P<url>\S+)(?:\]\[)(?P<desc>.+)(?:\]\])(?P<tags>.+)?`)
	matches := re.FindStringSubmatch(s)
	if len(matches) > 1 {
		l.AddToken("URL", strings.TrimSpace(matches[1]))
	}
	if len(matches) > 2 {
		l.AddToken("DESC", strings.TrimSpace(matches[2]))
	}
	if len(matches) > 3 {
		tags := strings.Split(matches[3], " ")
		for t := range tags {
			if tags[t] != "" && tags[t] != " " {
				tag := strings.ReplaceAll(tags[t], ":", "")
				l.AddToken("TAG", strings.TrimSpace(tag))
			}
		}
	}
	
	return l.Tokens
}