// ==UserScript==
// @name           AutoPagerize for Opera
// @namespace      http://w-shadow.com/
// @description    Automatically loads next page and inserts it into the current page.
// @include        http://*
// @include        https://*
// @exclude        https://mail.google.com/*
// @exclude        http://b.hatena.ne.jp/*
// ==/UserScript==
//
// This script is an Opera-compatible modification of the "AutoPagerize" GreaseMonkey script.
// Author : Janis Elsts (W-Shadow)
// URL : http://w-shadow.com/blog/2009/07/23/autopager-for-opera/
// License : GPL
//
//
// Original credit info follows :
// -----------------------------------------------------------------
// http://userscripts.org/scripts/show/8551 
//
// auther:  swdyh http://d.hatena.ne.jp/swdyh/
// version: 0.0.37 2009-05-07T13:52:56+09:00
//
// this script based on
// GoogleAutoPager(http://la.ma.la/blog/diary_200506231749.htm) and
// estseek autopager(http://la.ma.la/blog/diary_200601100209.htm).
// thanks to ma.la.
//
// Released under the GPL license
// http://www.gnu.org/copyleft/gpl.html
// 

(function() {

var URL = 'http://userscripts.org/scripts/show/8551'
var VERSION = '0.0.37'
var DEBUG = false
var AUTO_START = true
var BASE_REMAIN_HEIGHT = 400
var FORCE_TARGET_WINDOW = true
var USE_COUNTER = false
var XHR_TIMEOUT = 30 * 1000
/* //No cache = it's impractical to download config. updates
var SITEINFO_IMPORT_URLS = [
    'http://wedata.net/databases/AutoPagerize/items.json',
]
*/
var COLOR = {
    on: '#0f0',
    off: '#ccc',
    loading: '#0ff',
    terminated: '#00f',
    error: '#f0f'
}
var SITEINFO = [
	{
		"pageElement": "id(\"res\")/div[ol or div]",
		"url": "^http://[^.]+\.google\\.(?:[^.]{2,3}\.)?[^./]{2,3}/(?:c(?:se|ustom)|search)",
		"nextLink": 'id("nav")//td[last()]/a | id("nn")/parent::a',
    },
    , 
    /* sample
    {
        url:          'http://(.*).google.+/(search).+',
        nextLink:     'id("navbar")//td[last()]/a',
        pageElement:  '//div[@id="res"]/div',
        exampleUrl:   'http://www.google.com/search?q=nsIObserver',
    },
    */
    /* template
    {
        url:          '',
        nextLink:     '',
        pageElement:  '',
        exampleUrl:   '',
    },
    */
]
var MICROFORMAT = {
    url:          '.*',
    nextLink:     '//a[@rel="next"] | //link[@rel="next"]',
    insertBefore: '//*[contains(@class, "autopagerize_insert_before")]',
    pageElement:  '//*[contains(@class, "autopagerize_page_element")]',
}

var AutoPager = function(info) {
    this.pageNum = 1
    this.info = info
    this.state = AUTO_START ? 'enable' : 'disable'
    var self = this
    var url = this.getNextURL(info.nextLink, document, location.href)

    if ( !url ) {
        debug("getNextURL returns null. " + info.nextLink)
        return
    }
    if (info.insertBefore) {
        this.insertPoint = getFirstElementByXPath(info.insertBefore)
    }

    if (!this.insertPoint) {
        var lastPageElement = getElementsByXPath(info.pageElement).pop()
        if (lastPageElement) {
            this.insertPoint = lastPageElement.nextSibling ||
                lastPageElement.parentNode.appendChild(document.createTextNode(' '))
        }
    }

    if (!this.insertPoint) {
        debug("insertPoint not found.", lastPageElement, info.pageElement)
        return
    }

    this.requestURL = url
    this.loadedURLs = {}
    this.loadedURLs[location.href] = true
    var toggle = function() {self.stateToggle()}
    this.toggle = toggle
    this.scroll= function() { self.onScroll() }
    window.addEventListener("scroll", this.scroll, false)
    this.initIcon()
    this.initHelp()
    
    this.icon.addEventListener("mouseover",
        function(){self.viewHelp()}, false)
        
    var scrollHeight = getScrollHeight()
    var bottom = getElementPosition(this.insertPoint).top ||
        this.getPageElementsBottom() ||
        (Math.round(scrollHeight * 0.8))
    this.remainHeight = scrollHeight - bottom + BASE_REMAIN_HEIGHT
    this.onScroll()
}

AutoPager.prototype.getPageElementsBottom = function() {
    try {
        var elem = getElementsByXPath(this.info.pageElement).pop()
        return getElementBottom(elem)
    }
    catch(e) {}
}

AutoPager.prototype.initHelp = function() {
    var helpDiv = document.createElement('div')
    helpDiv.setAttribute('id', 'autopagerize_help')
    helpDiv.setAttribute('style', 'padding:5px;position:fixed;' +
                     'top:-200px;right:3px;font-size:10px;' +
                     'background:#fff;color:#000;border:1px solid #ccc;' +
                     'z-index:10002;text-align:left;font-weight:normal;' +
                     'line-height:120%;font-family:verdana;')

    var toggleDiv = document.createElement('div')
    toggleDiv.setAttribute('style', 'margin:0 0 0 50px;')
    var a = document.createElement('a')
    a.setAttribute('class', 'autopagerize_link')
    a.innerHTML = 'on/off'
    a.href = 'javascript:void(0)'
    a.setAttribute('style', 'text-decoration: underline;'); //the original #0f0 color hurts my eyes, so not using it here
    var self = this
    var toggle = function() {
        self.stateToggle()
        helpDiv.style.top = '-200px'
    }
    a.addEventListener('click', toggle, false)
    toggleDiv.appendChild(a)

    var s = '<div style="width:100px; float:left;">'
    for (var i in COLOR) {
        s += '<div style="float:left;width:1em;height:1em;' +
            'margin:0 3px;background-color:' + COLOR[i] + ';' +
            '"></div><div style="margin:0 3px">' + i + '</div>'
    }
    s += '</div>'
    var colorDiv = document.createElement('div')
    colorDiv.innerHTML = s
    helpDiv.appendChild(colorDiv)
    helpDiv.appendChild(toggleDiv)

    var versionDiv = document.createElement('div')
    versionDiv.setAttribute('style', 'clear:both;')
    versionDiv.innerHTML = '<a href="' + URL +
        '" style="text-decoration: underline;">AutoPagerize</a> ver ' + VERSION
    helpDiv.appendChild(versionDiv)
    document.body.appendChild(helpDiv)

    var proc = function(e) {
        var c_style = document.defaultView.getComputedStyle(helpDiv, '')
        var s = ['top', 'left', 'height', 'width'].map(function(i) {
            return parseInt(c_style.getPropertyValue(i)) })
        if (e.clientX < s[1] || e.clientX > (s[1] + s[3] + 11) ||
            e.clientY < s[0] || e.clientY > (s[0] + s[2] + 11)) {
                helpDiv.style.top = '-200px'
        }
    }
    helpDiv.addEventListener('mouseout', proc, false)
    this.helpLayer = helpDiv
    //GM_addStyle('#autopagerize_help a { color: #0f0; text-decoration: underline;}')
}

AutoPager.prototype.viewHelp = function() {
    this.helpLayer.style.top = '3px'
}

AutoPager.prototype.onScroll = function() {
    var scrollHeight = Math.max(document.documentElement.scrollHeight,
                                document.body.scrollHeight)
    var remain = scrollHeight - window.innerHeight - window.pageYOffset
    if (this.state == 'enable' && remain < this.remainHeight) {
          this.request()
    }
}

AutoPager.prototype.stateToggle = function() {
    if (this.state == 'enable') {
        this.disable()
    }
    else {
        this.enable()
    }
}

AutoPager.prototype.enable = function() {
    this.state = 'enable'
    this.icon.style.background = COLOR['on']
    this.icon.style.opacity = 1
}

AutoPager.prototype.disable = function() {
    this.state = 'disable'
    this.icon.style.background = COLOR['off']
    this.icon.style.opacity = 0.5
}

AutoPager.prototype.request = function() {
    if (!this.requestURL || this.lastRequestURL == this.requestURL) {
        return
    }

    if (!this.canHandleCrossDomainRequest()) {
		debug("Can't handle cross-domain requests!"); 
        return
    }
    debug("Requesting URL " + this.requestURL);

    this.lastRequestURL = this.requestURL
    var self = this
    var mime = 'text/html; charset=' + document.characterSet
    var headers = {}
    if (isSameDomain(this.requestURL)) {
        headers.Cookie = document.cookie
    }
    var opt = {
        method: 'get',
        url: this.requestURL,
        headers: headers,
        overrideMimeType: mime,
        onerror: this.error,
        onload: function(res) {	//Note : this will be overwritten, thus it's redundant.
            self.requestLoad.apply(self, [res])
        }
    }
    AutoPager.requestFilters.forEach(function(i) { i(opt) }, this)
    this.showLoading(true)
    
    //In Opera we must use XMLHttpRequest, which is a bit different from GM_xmlhttpRequest
    var req = new XMLHttpRequest();
    
    req.open(opt.method, opt.url, true);  
    req.onload = function(e){
		self.requestLoad.apply(self, [req]);
    };
    req.onerror = opt.onerror;
    req.overrideMimeType(opt.overrideMimeType);
    for (var header in headers){
		req.setRequestHeader(header, headers[header]);
    }
    
	req.send(null);
}

AutoPager.prototype.showLoading = function(sw) {
    if (sw) {
        this.icon.style.background = COLOR['loading']
    }
    else {
        this.icon.style.background = COLOR['on']
    }
}

AutoPager.prototype.requestLoad = function(res) {
    if (!this.canHandleCrossDomainRequest()) {
        return
    }

    AutoPager.responseFilters.forEach(function(i) {
        i(res, this.requestURL)
    }, this)

	/*
    if (res.finalUrl) {
        this.requestURL = res.finalUrl
    }
    */

    var t = res.responseText
    var htmlDoc = createHTMLDocumentByString(t)
    AutoPager.documentFilters.forEach(function(i) {
        i(htmlDoc, this.requestURL, this.info)
    }, this)
    try {
        var page = getElementsByXPath(this.info.pageElement, htmlDoc)
        var url = this.getNextURL(this.info.nextLink, htmlDoc, this.requestURL)
    }
    catch(e){
        log(e)
        this.error()
        return
    }

    if (!page || page.length < 1 ) {
        debug('pageElement not found.' , this.info.pageElement)
        this.terminate()
        return
    }

    if (this.loadedURLs[this.requestURL]) {
        debug('page is already loaded.', this.requestURL, this.info.nextLink)
        this.terminate()
        return
    }

    this.loadedURLs[this.requestURL] = true
    page = this.addPage(htmlDoc, page)
    AutoPager.filters.forEach(function(i) {
        i(page)
    })
    this.requestURL = url
    this.showLoading(false)
    this.onScroll()
    if (!url) {
        debug('[requestLoad] nextLink not found.', this.info.nextLink, htmlDoc)
        this.terminate()
    }
}

AutoPager.prototype.addPage = function(htmlDoc, page) {
    var HTML_NS  = 'http://www.w3.org/1999/xhtml'
    var hr = document.createElementNS(HTML_NS, 'hr')
    var p  = document.createElementNS(HTML_NS, 'p')
    hr.setAttribute('class', 'autopagerize_page_separator')
    p.setAttribute('class', 'autopagerize_page_info')
    var self = this

    if (page[0] && page[0].tagName == 'TR') {
        var insertParent = this.insertPoint.parentNode
        var colNodes = getElementsByXPath('child::tr[1]/child::*[self::td or self::th]', insertParent)

        var colums = 0
        for (var i = 0, l = colNodes.length; i < l; i++) {
            var col = colNodes[i].getAttribute('colspan')
            colums += parseInt(col, 10) || 1
        }
        var td = document.createElement('td')
        // td.appendChild(hr)
        td.appendChild(p)
        var tr = document.createElement('tr')
        td.setAttribute('colspan', colums)
        tr.appendChild(td)
        insertParent.insertBefore(tr, this.insertPoint)
    }
    else {
        this.insertPoint.parentNode.insertBefore(hr, this.insertPoint)
        this.insertPoint.parentNode.insertBefore(p, this.insertPoint)
    }

    p.innerHTML = 'page: <a class="autopagerize_link" href="' +
        this.requestURL.replace(/&/g, '&amp;') + '">' + (++this.pageNum) + '</a>'
    return page.map(function(i) {
        var pe = document.importNode(i, true)
        self.insertPoint.parentNode.insertBefore(pe, self.insertPoint)
        return pe
    })
}

AutoPager.prototype.initIcon = function() {
    var div = document.createElement("div")
    div.setAttribute('id', 'autopagerize_icon')
    with (div.style) {
        fontSize   = '12px'
        position   = 'fixed'
        top        = '3px'
        right      = '3px'
        background = COLOR['on']
        color      = '#fff'
        width = '10px'
        height = '10px'
        zIndex = '10001'
        if (this.state != 'enable') {
            background = COLOR['off']
        }
    }
    document.body.appendChild(div)
    this.icon = div
}

AutoPager.prototype.getNextURL = function(xpath, doc, url) {
    var nextLink = getFirstElementByXPath(xpath, doc)
    if (nextLink) {
        var nextValue = nextLink.href || nextLink.action || nextLink.value
        if (nextValue.match(/^http(s)?:/)) {
            return nextValue
        }
        else {
            var base = getFirstElementByXPath('//base[@href]', doc)
            return resolvePath(nextValue, (base ? base.href : url))
        }
    }
}

AutoPager.prototype.canHandleCrossDomainRequest = function() {
    if (!supportsFinalUrl()) {
        if (!isSameDomain(this.requestURL)) {
            this.error()
            return false
        }
    }
    return true
}

AutoPager.prototype.terminate = function() {
    this.icon.style.background = COLOR['terminated']
    window.removeEventListener('scroll', this.scroll, false)
    var self = this
    setTimeout(function() {
        self.icon.parentNode.removeChild(self.icon)
    }, 1500)
}

AutoPager.prototype.error = function() {
    this.icon.style.background = COLOR['error']
    window.removeEventListener('scroll', this.scroll, false)
}

AutoPager.documentFilters = []
AutoPager.requestFilters = []
AutoPager.responseFilters = []
AutoPager.filters = []

var parseInfo = function(str) {
    var lines = str.split(/\r\n|\r|\n/)
    var re = /(^[^:]*?):(.*)$/
    var strip = function(str) {
        return str.replace(/^\s*/, '').replace(/\s*$/, '')
    }
    var info = {}
    for (var i = 0; i < lines.length; i++) {
        if (lines[i].match(re)) {
            info[RegExp.$1] = strip(RegExp.$2)
        }
    }
    var isValid = function(info) {
        var infoProp = ['url', 'nextLink', 'pageElement']
        for (var i = 0; i < infoProp.length; i++) {
            if (!info[infoProp[i]]) {
                return false
            }
        }
        return true
    }
    return isValid(info) ? info : null
}
var launchAutoPager = function(list) {
    if (list.length == 0) {
        return
    }
    for (var i = 0; i < list.length; i++) {
        try {
            if (ap) {
                return
            }
            else if (!location.href.match(list[i].url)) {
            }
            else if (!getFirstElementByXPath(list[i].nextLink)) {
                // FIXME microformats case detection.
                // limiting greater than 12 to filter microformats like SITEINFOs.
                if (list[i].url.length > 12 ) {
                    debug("nextLink not found. " + list[i].nextLink + " Index : "+i)
                }
            }
            else if (!getFirstElementByXPath(list[i].pageElement)) {
                if (list[i].url.length > 12 ) {
                    debug("pageElement not found. " + list[i].pageElement)
                }
            }
            else {
				debug(
					"Found a usable config for " + location.href + '\n' +
					' URL pattern : ' + list[i].url  + '\n' +
					' nextLink : ' + list[i].nextLink + '\n' +
					' Index : ',i  + '\n'
				 );
                ap = new AutoPager(list[i])
                return
            }
        }
        catch(e) {
            log(e)
            continue
        }
    }
}

var linkFilter = function(doc, url) {
    var base = getFirstElementByXPath('//base[@href]', doc)
    var baseUrl = base ? base.href : url
    var isSameBase = isSameBaseUrl(location.href, baseUrl)
    if (!FORCE_TARGET_WINDOW && isSameBase) {
        return
    }

    var anchers = getElementsByXPath('descendant-or-self::a[@href]', doc)
    anchers.forEach(function(i) {
        var attrHref = i.getAttribute('href')
        if (FORCE_TARGET_WINDOW && !attrHref.match(/^#|^javascript:/) &&
            i.className.indexOf('autopagerize_link') < 0) {
            i.target = '_blank'
        }
        if (!isSameBase && !attrHref.match(/^#|^\w+:/)) {
            i.href = resolvePath(i.href, baseUrl)
        }
    })
}
AutoPager.documentFilters.push(linkFilter)

if (typeof(window.AutoPagerize) == 'undefined') {
    window.AutoPagerize = {}
    window.AutoPagerize.addFilter = function(f) {
        AutoPager.filters.push(f)
    }
    window.AutoPagerize.addDocumentFilter = function(f) {
        AutoPager.documentFilters.push(f)
    }
    window.AutoPagerize.addResponseFilter = function(f) {
        AutoPager.responseFilters.push(f)
    }
    window.AutoPagerize.addRequestFilter = function(f) {
        AutoPager.requestFilters.push(f)
    }

    var ev = document.createEvent('Events')
    ev.initEvent('GM_AutoPagerizeLoaded', false, true)
    window.dispatchEvent(ev)
}

var ap = null
launchAutoPager(SITEINFO)
launchAutoPager([MICROFORMAT])

// utility functions.
function createHTMLDocumentByString(str) {
    if (document.documentElement.nodeName != 'HTML') {
        return new DOMParser().parseFromString(str, 'application/xhtml+xml')
    }
    var html = strip_html_tag(str)
    var htmlDoc = document.implementation.createDocument(null, 'html', null)
    var fragment = createDocumentFragmentByString(html)
    try {
        fragment = htmlDoc.adoptNode(fragment)
    } catch(e) {
        fragment = htmlDoc.importNode(fragment, true)
    }
    htmlDoc.documentElement.appendChild(fragment)
    return htmlDoc
}

function getElementsByXPath(xpath, node) {
    var nodesSnapshot = getXPathResult(xpath, node,
        XPathResult.ORDERED_NODE_SNAPSHOT_TYPE)
    var data = []
    for (var i = 0; i < nodesSnapshot.snapshotLength; i++) {
        data.push(nodesSnapshot.snapshotItem(i))
    }
    return data
}

function getFirstElementByXPath(xpath, node) {
    var result = getXPathResult(xpath, node,
        XPathResult.FIRST_ORDERED_NODE_TYPE)
    return result.singleNodeValue
}

function getXPathResult(xpath, node, resultType) {
    var node = node || document
    var doc = node.ownerDocument || node
    
    var resolver = doc.createNSResolver(node.documentElement || node)
    // Use |node.lookupNamespaceURI('')| for Opera 9.5 [WSH : actually, null seems to work fine]
    var defaultNS = node.lookupNamespaceURI(null) 
    if (defaultNS) {
        const defaultPrefix = '__default__'
        xpath = addDefaultPrefix(xpath, defaultPrefix)
        var defaultResolver = resolver
        resolver = function (prefix) {
            return (prefix == defaultPrefix)
                ? defaultNS : defaultResolver.lookupNamespaceURI(prefix)
        }
    }
    
    return doc.evaluate(xpath, node, resolver, resultType, null);
}

function addDefaultPrefix(xpath, prefix) {
    const tokenPattern = /([A-Za-z_\u00c0-\ufffd][\w\-.\u00b7-\ufffd]*|\*)\s*(::?|\()?|(".*?"|'.*?'|\d+(?:\.\d*)?|\.(?:\.|\d+)?|[\)\]])|(\/\/?|!=|[<>]=?|[\(\[|,=+-])|([@$])/g
    const TERM = 1, OPERATOR = 2, MODIFIER = 3
    var tokenType = OPERATOR
    prefix += ':'
    function replacer(token, identifier, suffix, term, operator, modifier) {
        if (suffix) {
            tokenType =
                (suffix == ':' || (suffix == '::' &&
                 (identifier == 'attribute' || identifier == 'namespace')))
                ? MODIFIER : OPERATOR
        }
        else if (identifier) {
            if (tokenType == OPERATOR && identifier != '*') {
                token = prefix + token
            }
            tokenType = (tokenType == TERM) ? OPERATOR : TERM
        }
        else {
            tokenType = term ? TERM : operator ? OPERATOR : MODIFIER
        }
        return token
    }
    return xpath.replace(tokenPattern, replacer)
}

function createDocumentFragmentByString(str) {
    var range = document.createRange()
    range.setStartAfter(document.body)
    return range.createContextualFragment(str)
}

function log(message) {
    if (typeof console == 'object') {
        console.log(message)
    } else if (typeof opera == 'object'){
		opera.postError('[AutoPager] ' + message);
    }
}

function debug() {
    if ( typeof DEBUG != 'undefined' && DEBUG ) {
		if (typeof console == 'object') {
			console.log.apply(this, arguments)
		} else if (typeof opera == 'object'){
			opera.postError.apply(this, arguments);
		}
    }
}

function getElementPosition(elem) {
    var offsetTrail = elem
    var offsetLeft  = 0
    var offsetTop   = 0
    while (offsetTrail) {
        offsetLeft += offsetTrail.offsetLeft
        offsetTop  += offsetTrail.offsetTop
        offsetTrail = offsetTrail.offsetParent
    }
    offsetTop = offsetTop || null
    offsetLeft = offsetLeft || null
    return {left: offsetLeft, top: offsetTop}
}

function getElementBottom(elem) {
    var c_style = document.defaultView.getComputedStyle(elem, '')
    var height  = 0
    var prop    = ['height', 'borderTopWidth', 'borderBottomWidth',
                   'paddingTop', 'paddingBottom',
                   'marginTop', 'marginBottom']
    prop.forEach(function(i) {
        var h = parseInt(c_style[i])
        if (typeof h == 'number') {
            height += h
        }
    })
    var top = getElementPosition(elem).top
    return top ? (top + height) : null
}

function getScrollHeight() {
    return Math.max(document.documentElement.scrollHeight,
                                document.body.scrollHeight)
}

function isSameDomain(url) {
    return location.host == url.split('/')[2]
}

function isSameBaseUrl(urlA, urlB) {
    return (urlA.replace(/[^/]+$/, '') == urlB.replace(/[^/]+$/, ''))
}

function supportsFinalUrl() {
	return false;
}

function resolvePath(path, base) {
    var XHTML_NS = "http://www.w3.org/1999/xhtml"
    var XML_NS   = "http://www.w3.org/XML/1998/namespace"
    var a = document.createElementNS(XHTML_NS, 'a')
    a.setAttributeNS(XML_NS, 'xml:base', base)
    a.href = path
    return a.href
}

function strip_html_tag(str) {
    var re = /^[\s\S]*?<html(?:[ \t\r\n][^>]*)?>|<\/html[ \t\r\n]*>[\w\W]*$/ig
    return str.replace(re, '')
}

})();