'use strict'

import Plugin from "markdown-it-regexp";
import extend from "extend";

var illegalRe = /[\/\?<>\\\*\|"]/g;
var controlRe = /[\x00-\x1f\x80-\x9f]/g;
var reservedRe = /^\.+$/;
var windowsReservedRe = /^(con|prn|aux|nul|com[0-9]|lpt[0-9])(\..*)?$/i;
var windowsTrailingRe = /[\. ]+$/;

function sanitize(input) {
  const replacement = '';
  if (typeof input !== 'string') {
    throw new Error('Input must be string');
  }
  var sanitized = input
    .replace(illegalRe, replacement)
    .replace(controlRe, replacement)
    .replace(reservedRe, replacement)
    .replace(windowsReservedRe, replacement)
    .replace(windowsTrailingRe, replacement);
  return sanitized;
}

export default (options) => {
    const defaults = {
        baseURL: '/',
        relativeBaseURL: './',
        makeAllLinksAbsolute: false,
        uriSuffix: '.html',
        htmlAttributes: {
        },
        generatePageNameFromLabel: (label) => {
            return label
        },
        postProcessPageName: (pageName) => {
            pageName = pageName.trim()
            pageName = pageName.split('/').map(sanitize).map(sanitize).join('/')
            pageName = pageName.replace(/\s+/g, '_')
            return pageName
        },
        postProcessLabel: (label) => {
            label = label.trim()
            return label
        }
    }

    options = extend(true, defaults, options)

    function isAbsolute(pageName) {
        return options.makeAllLinksAbsolute || pageName.charCodeAt(0) === 0x2F/* / */
    }

    function removeInitialSlashes(str) {
        return str.replace(/^\/+/g, '')
    }

    return Plugin(
        /(#?)\[\[([^\]]+)\]\]/,
        (match, utils) => {
            let label = ''
            let pageName = ''
            let href = ''
            let htmlAttrs = []
            let htmlAttrsString = ''

            let tag = match[1]

            label = match[2]
            pageName = options.generatePageNameFromLabel(label)

            label = options.postProcessLabel(label)
            pageName = options.postProcessPageName(pageName)

            // make sure none of the values are empty
            if (!label || !pageName) {
                return match.input
            }

            if (isAbsolute(pageName)) {
                pageName = removeInitialSlashes(pageName)
                href = options.baseURL + pageName + options.uriSuffix
            }
            else {
                href = options.relativeBaseURL + pageName + options.uriSuffix
            }
            href = utils.escape(href)

            htmlAttrs.push(`href="${href}"`)
            for (let attrName in options.htmlAttributes) {
                const attrValue = options.htmlAttributes[attrName]
                htmlAttrs.push(`${attrName}="${attrValue}"`)
            }
            htmlAttrsString = htmlAttrs.join(' ')

            return `<a ${htmlAttrsString}>${tag}${label}</a>`
        }
    )
}