'use strict'

var util = require('util')

function Plugin(options) {
    var self = function (md) {
        self.options = options
        self.init(md)
    }

    self.__proto__ = Plugin.prototype
    self.id = 'wikilinks'

    return self
}

util.inherits(Plugin, Function)

Plugin.prototype.init = function (md) {
    md.inline.ruler.push(this.id, this.parse.bind(this))
    md.renderer.rules[this.id] = this.render.bind(this)
}

export function linkParser(id, state, silent) {
    let input = state.src.slice(state.pos);

    const match = /^#?\[\[/.exec(input)
    if (!match) {
        return false
    }

    let prefixLength = match[0].length
    let p = state.pos + prefixLength
    let open = 2
    while (p < state.src.length - 1 && open > 0) {
        if (state.src[p] === '[' && state.src[p + 1] === '[') {
            open += 2
            p += 2
        } else if (state.src[p] === ']' && state.src[p + 1] === ']') {
            open -= 2
            p += 2
        } else {
            p++
        }
    }

    if (open === 0) {
        if (!silent) {
            let link = state.src.slice(state.pos + prefixLength, p - 2)
            let token = state.push(id, '', 0)
            token.meta = {match: link, tag: prefixLength === 3}
        }
        state.pos = p
        return true
    }

    return false
}

Plugin.prototype.parse = function (state, silent) {
    return linkParser(this.id, state, silent)
}

Plugin.prototype.render = function (tokens, id, options, env) {
    let {match: link, tag} = tokens[id].meta
    if (tag) {
        if (link === 'TODO') {
            return '<input type="checkbox" class="checkbox">';
        } else if (link === 'DONE') {
            return '<input type="checkbox" class="checkbox" checked>';
        }
    }
    return '<a href="'+this.options.relativeBaseURL+encodeURIComponent(link.replace(/ +/g, '_')) + '" class="wiki-link">' + (tag ? '#' : '') + link + '</a>';
}

export default (options) => {
    return Plugin(options);
}