package main

import (
	"log"
	"regexp"
)

var (
	alias      = regexp.MustCompile(`\|(.*)`)
	link       = regexp.MustCompile(`^([a-zA-Z ]+)?[\|\#\^\\]?`)
	subsection = regexp.MustCompile(`#([\w\s]+)`)
	block      = regexp.MustCompile(`#\^([a-zA-Z ]+)`)
	wholeLink  = regexp.MustCompile(`\[\[(.*)\]\]`)
)

type Link struct {
	Dest, Alias, Subsection, Block string
}

func ExtractLink(raw string) Link {
	var li Link

	rawLinkMatch := wholeLink.FindAllStringSubmatch(raw, -1)
	var rawLink string
	if len(rawLinkMatch) > 0 {
		rawLink = rawLinkMatch[0][1]
	}

	l := link.FindAllStringSubmatch(rawLink, -1)
	if len(l) > 0 {
		li.Dest = l[0][1]
	}

	a := alias.FindAllStringSubmatch(rawLink, -1)
	if len(a) > 0 {
		li.Alias = a[0][1]
	}

	s := subsection.FindAllStringSubmatch(rawLink, -1)
	if len(s) > 0 {
		li.Subsection = s[0][1]
	}

	b := block.FindAllStringSubmatch(rawLink, -1)
	if len(b) > 0 {
		li.Block = b[0][1]
	}

	return li
}

func main() {
	log.Printf("%#v\n", ExtractLink(`Embedding a link in a bigger block of text [[Regular Link#^link to block]] shouldn't cause any problems `))
}