#!/usr/bin/env node

var input = ""

process.stdin.resume()

process.stdin.on("data", function(chunk) {

input += chunk.toString("utf8")

})

process.stdin.on("end", function() {

var re = /<(p|pre\ data-language|h[23])\b[^>]*>/g, m

var pos = 0

while (m = re.exec(input)) {

var tag = m[1].match(/^\w+/)[0]

var start = m.index + m[0].length

var end = input.indexOf("</" + tag + ">", start)

re.lastIndex = end + 3 + tag.length

var type, toHash = toPlainText(input.slice(start, end))

if (tag == "pre") {

type = "c"

} else if (tag == "p") {

type = "p"

toHash = startAndEnd(toHash)

} else {

type = "h"

}

var mark = type + "_" + hash(toHash)

var bookmark = "<a class=" + type + "_ident id=\"" + mark + "\" href=\"#" + mark + "\"></a>"

process.stdout.write(input.slice(pos, start) + bookmark)

pos = start

}

process.stdout.write(input.slice(pos))

})

function hash(string) {

var sum = require("crypto").createHash("sha1");

sum.update(string);

return sum.digest("base64").slice(0, 10);

}

function toPlainText(text) {

return text.replace(/<[^>]+>|&[^;]+;/g, "");

}

function startAndEnd(text) {

var words = text.split(/\W+/);

if (!words[0]) words.shift();

if (!words[words.length - 1]) words.pop();

if (words.length <= 6) return words.join(" ");

return words.slice(0, 3).join(" ") + " " + words.slice(words.length - 3).join(" ");

}