/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/**
   A request object is used to track an async action.
   While the action is running, isPending is true.
   Functions issuing an async action usually take a response function along
   with their parameters, typically named respFunc.
   That function is called *after* the action has ended (i.e. isPending of the
   issued action/request is false when called, status remains stable).
   The response function gets the ended request as first parameter to check
   whether the request has been successful and get its data.
   The request function itself may return either
   - a further calIOperation request object, i.e. an async continuation
   - some data (incl null/undefined) which is the result of the async function,
     indicating that there is no further continuation
*/

Components.utils.import("resource://gre/modules/Services.jsm");
Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");

function generateRequestId() {
    if (!generateRequestId.mRequestPrefix) {
        generateRequestId.mRequestPrefix = (cal.getUUID() + "-");
        generateRequestId.mRequestId = 0;
    }
    ++generateRequestId.mRequestId;
    return (generateRequestId.mRequestPrefix + generateRequestId.mRequestId);
}

function calWcapRequest(respFunc, logContext) {
    this.wrappedJSObject = this;
    this.m_logContext = logContext;
    this.m_id = generateRequestId();
    this.m_isPending = true;
    this.m_status = NS_OK;
    this.m_respFunc = respFunc;
    this.m_attachedRequests = [];
}
calWcapRequest.prototype = {
    m_logContext: null,
    m_parentRequest: null,
    m_id: 0,
    m_isPending: true,
    m_status: NS_OK,
    m_respFunc: null,
    m_attachedRequests: null,
    m_locked: false,

    get parentRequest() {
        return this.m_parentRequest;
    },
    set parentRequest(req) {
        if (this.parentRequest) {
            logError("already has parent!", this);
        }
        this.detachFromParent(); // detach without error
        return (this.m_parentRequest = req);
    },

    /** The following locking is necessary when scheduling multiple async
        requests; one cannot be sure that e.g. the first completes quickly
        and responds the whole parent request when detaching.
    */
    lockPending: function calWcapRequest_lockPending() {
        this.m_locked = true;
    },
    unlockPending: function calWcapRequest_unlockPending() {
        if (this.m_locked) {
            this.m_locked = false;
            // assures that respFunc is executed:
            if (this.m_attachedRequests.length == 0) {
                this.execRespFunc();
            }
        }
    },

    toString: function calWcapRequest_toString() {
        var ret = ("calWcapRequest id=" + this.id +
                   ", parent-id=" + (this.parentRequest ? this.parentRequest.id : "<none>") +
                   " (" + this.m_logContext + ")");
        if (LOG_LEVEL > 2 && this.m_attachedRequests.length > 0) {
            ret += "\nattached requests:";
            for each (var req in this.m_attachedRequests) {
                ret += ("\n#" + req.id + "\t" + req);
            }
        }
        ret += (", isPending=" + this.isPending);
        ret += (", status=" + errorToString(this.status));
        return ret;
    },

    attachSubRequest: function calWcapRequest_attachSubRequest(req) {
        if (req) {
            if (!this.m_attachedRequests.some( function(req_) { return req.id == req_.id; } )) {
                if (req.isPending) {
                    this.m_attachedRequests.push(req);
                    req.parentRequest = this;
                    log("attachSubRequest()", this);
                } else if (!this.m_locked && this.m_attachedRequests.length == 0) {
                    this.execRespFunc(req.status);
                }
            } else {
                logError("request already attached: " + req.id, this);
            }
        }
    },

    detachSubRequest: function calWcapRequest_detachSubRequest(req, err) {
        this.m_attachedRequests = this.m_attachedRequests.filter( function(req_) { return req.id != req_.id; } );
        if (err) {
            // first failing sub request stops parent request:
            this.execRespFunc(err);
        }
        // assures that respFunc is executed after all sub requests have been completed:
        else if (!this.m_locked && this.m_attachedRequests.length == 0) {
            this.execRespFunc();
        }
    },

    cancelAllSubRequests: function calWcapRequest_cancelAllSubRequests(status) {
        var attachedRequests = this.m_attachedRequests;
        this.m_attachedRequests = [];
        attachedRequests.forEach( function(req) { req.cancel(null); } );
    },

    detachFromParent: function calWcapRequest_detachFromParent(err) {
        var parentRequest = this.m_parentRequest;
        if (parentRequest) {
            this.m_parentRequest = null;
            parentRequest.detachSubRequest(this, err);
        }
    },

    execRespFunc: function calWcapRequest_execRespFunc(err, data) {
        if (this.isPending) {
            this.m_isPending = false;
            if (err) {
                this.m_status = err;
            }
            this.cancelAllSubRequests();
            var respFunc = this.m_respFunc;
            if (respFunc) {
                this.m_respFunc = null; // call once only
                if (LOG_LEVEL > 2) {
                    log("response exec: " + errorToString(err), this);
                }
                try {
                    respFunc(this, err, data);
                } catch (exc) {
                    this.m_status = exc;
                    // don't pump into error console, may be handled:
                    log("error: " + errorToString(exc), this);
                }
            }
            this.detachFromParent(this.m_status);
        }
    },

    execSubRespFunc: function calWcapRequest_execSubRespFunc(func, err, data) {
        try {
            func(err, data);
        } catch (exc) {
            this.execRespFunc(exc);
        }
    },

    // calIOperation:
    get id() {
        return this.m_id;
    },
    get isPending() {
        return this.m_isPending;
    },
    get status() {
        return (this.m_status === null ? NS_OK : this.m_status);
    },

    cancel: function calWcapRequest_cancel(status) {
        if (!status) {
            status = calIErrors.OPERATION_CANCELLED;
        }
        this.execRespFunc(status);
    }
};

function calWcapNetworkRequest(url, respFunc, bLogging) {
    this.wrappedJSObject = this;
    this.m_id = generateRequestId();
    this.m_url = url;
    this.m_respFunc = respFunc;
    this.m_bLogging = (bLogging === undefined ? true : bLogging);
}
var calWcapNetworkRequestClassID = Components.ID("{e3c62b37-83cf-41ec-9872-0af9f952430a}");
var calWcapNetworkRequestInterfaces = [
    Components.interfaces.nsIUnicharStreamLoaderObserver,
    Components.interfaces.nsIInterfaceRequestor,
    Components.interfaces.nsIChannelEventSink,
    Components.interfaces.calIOperation,
];
calWcapNetworkRequest.prototype = {
    m_id: 0,
    m_url: null,
    m_loader: null,
    m_respFunc: null,
    m_bLogging: false,

    classID: calWcapNetworkRequestClassID,
    QueryInterface: XPCOMUtils.generateQI(calWcapNetworkRequestInterfaces),
    classInfo: XPCOMUtils.generateCI({
        classID: calWcapNetworkRequestClassID,
        contractID: "@mozilla.org/calendar/wcap/network-request;1",
        classDescription: "Sun Java System Calendar Server WCAP Network Request",
        interfaces: calWcapNetworkRequestInterfaces
    }),

    /**
     * @see nsIInterfaceRequestor
     * @see calProviderUtils.jsm
     */
    getInterface: cal.InterfaceRequestor_getInterface,

    /**
     * prepareChannel
     * Prepares the passed channel to match this objects properties
     *
     * @param aChannel    The Channel to be prepared
     */
    prepareChannel: function calWcapNetworkRequest_prepareChannel(aChannel) {
        // No caching
        aChannel.loadFlags |= Components.interfaces.nsIRequest.LOAD_BYPASS_CACHE;
        aChannel = aChannel.QueryInterface(Components.interfaces.nsIHttpChannel);
        aChannel.requestMethod = "GET";
    },

    /**
     * @see nsIChannelEventSink
     */
    asyncOnChannelRedirect: function calWcapNetworkRequest_asyncOnChannelRedirect(aOldChannel,
                                                                                  aNewChannel,
                                                                                  aFlags,
                                                                                  aCallback) {
        // all we need to do to the new channel is the basic preparation
        this.prepareChannel(aNewChannel);
        aCallback.onRedirectVerifyCallback(Components.results.NS_OK);
    },

    /**
     * @see nsIUnicharStreamLoaderObserver
     */
    onDetermineCharset: function calWcapNetworkRequest_onDetermineCharset(loader,
                                                                          context,
                                                                          firstSegment,
                                                                          length) {
        var channel = null;
        if (loader) {
            channel = loader.channel;
        }
        var charset = null;
        if (channel) {
            charset = channel.contentCharset;
        }
        if (!charset || charset.length == 0) {
            charset = "UTF-8";
        }
        return charset;
    },

    /**
     * @see nsIUnicharStreamLoaderObserver
     */
    onStreamComplete: function calWcapNetworkRequest_onStreamComplete(aLoader,
                                                                      aContext,
                                                                      aStatus,
                                                                      unicharData) {
        this.m_loader = null;

        if (LOG_LEVEL > 0 && this.m_bLogging) {
            log("status: " + errorToString(aStatus), this);
        }
        if (aStatus != Components.results.NS_OK) {
            this.execRespFunc(aStatus);
            return;
        }

        if (LOG_LEVEL > 2 && this.m_bLogging) {
            log("contentCharset = " + aLoader.charset + "\nrequest result:\n" + unicharData, this);
        }

        var httpChannel = aLoader.channel.QueryInterface(Components.interfaces.nsIHttpChannel);
        switch (httpChannel.responseStatus / 100) {
            case 2: /* 2xx codes */
                // Everything worked out, we are done
                this.execRespFunc(aStatus, unicharData);
                break;
            default: {
                // Something else went wrong
                var error = ("A request Error Occurred. Status Code: " +
                             httpChannel.responseStatus + " " +
                             httpChannel.responseStatusText + " Body: " +
                             unicharData);
                this.execRespFunc(Components.Exception(error, NS_BINDING_FAILED));
                break;
            }
        }
    },

    toString: function calWcapNetworkRequest_toString() {
        var ret = ("calWcapNetworkRequest id=" + this.id +
                   ", parent-id=" + (this.parentRequest ? this.parentRequest.id : "<none>"));
        if (this.m_bLogging) {
            ret += (" (" + this.m_url + ")");
        }
        ret += (", isPending=" + this.isPending);
        ret += (", status=" + errorToString(this.status));
        return ret;
    },

    m_parentRequest: null,
    get parentRequest() {
        return this.m_parentRequest;
    },
    set parentRequest(req) {
        if (this.parentRequest) {
            logError("already has parent!", this);
        }
        this.detachFromParent(); // detach without error
        return (this.m_parentRequest = req);
    },

    // calIOperation:
    get id() {
        return this.m_id;
    },

    m_isPending: true,
    get isPending() {
        return this.m_isPending;
    },

    get status() {
        return (this.request ? this.request.status : NS_OK);
    },

    detachFromParent: function calWcapNetworkRequest_detachFromParent(err) {
        var parentRequest = this.m_parentRequest;
        if (parentRequest) {
            this.m_parentRequest = null;
            parentRequest.detachSubRequest(this, err);
        }
    },

    get request() {
        return (this.m_loader ? this.m_loader.channel : null);
    },

    cancel: function calWcapNetworkRequest_cancel(status) {
        if (!status) {
            status = calIErrors.OPERATION_CANCELLED;
        }
        this.execRespFunc(status);
        // xxx todo: check whether this works on redirected channels!
        var request = this.request;
        if (request && request.isPending()) {
            log("canceling netwerk request...", this);
            request.cancel(NS_BINDING_FAILED);
            this.m_loader = null;
        }
    },

    execRespFunc: function calWcapNetworkRequest_execRespFunc(err, str) {
        if (this.isPending) {
            this.m_isPending = false;
            var respFunc = this.m_respFunc;
            if (respFunc) {
                this.m_respFunc = null; // call once only
                if (LOG_LEVEL > 2 && this.m_bLogging) {
                    log("response exec: " + errorToString(err), this);
                }
                try {
                    respFunc(err, str);
                    err = null; // may have been handled
                } catch (exc) {
                    // don't pump into error console, may be handled:
                    log("error: " + errorToString(exc), this);
                    err = exc;
                }
            }
            this.detachFromParent(err);
        }
    },

    execSubRespFunc: function calWcapNetworkRequest_execSubRespFunc(func, err, data) {
        try {
            func(err, data);
        } catch (exc) {
            this.execRespFunc(exc);
        }
    }
};

function issueNetworkRequest(parentRequest, respFunc, url, bLogging) {
    var netRequest = new calWcapNetworkRequest(url, respFunc, bLogging);
    if (parentRequest) {
        parentRequest.attachSubRequest(netRequest);
    }
    try {
        var uri = Services.io.newURI(url, null, null);
        var channel = Services.io.newChannelFromURI2(uri,
                                                     null,
                                                     Services.scriptSecurityManager.getSystemPrincipal(),
                                                     null,
                                                     Components.interfaces.nsILoadInfo.SEC_NORMAL,
                                                     Components.interfaces.nsIContentPolicy.TYPE_OTHER);
        netRequest.prepareChannel(channel);
        channel = channel.QueryInterface(Components.interfaces.nsIHttpChannel);
        channel.redirectionLimit = 3;
        channel.notificationCallbacks = netRequest;
        var loader = Components.classes["@mozilla.org/network/unichar-stream-loader;1"]
                               .createInstance(Components.interfaces.nsIUnicharStreamLoader);
        netRequest.m_loader = loader;

        log("opening channel.", netRequest);
        loader.init(netRequest,
                    Components.interfaces.nsIUnicharStreamLoader.DEFAULT_SEGMENT_SIZE);
        channel.asyncOpen(loader, null);
    } catch (exc) {
        netRequest.execRespFunc(exc);
    }
}

function getWcapRequestStatusString(xml) {
    var str = "request status: ";
    var items = xml.getElementsByTagName("RSTATUS");
    if (items != null && items.length > 0) {
        str += items.item(0).textContent;
    } else {
        str += "none";
    }
    return str;
}

function stringToIcal(session, data, expectedErrno) {
    if (!data || data.length == 0) { // assuming time-out; WTF.
        throw new Components.Exception(errorToString(calIWcapErrors.WCAP_LOGIN_FAILED),
                                       calIWcapErrors.WCAP_LOGIN_FAILED);
    }
    var icalRootComp;
    try {
        icalRootComp = getIcsService().parseICS(data, session /* implements calITimezoneProvider */);
    } catch (exc) { // map into more useful error string:
        throw new Components.Exception("error parsing ical data!", calIErrors.ICS_PARSE);
    }
    checkWcapIcalErrno(icalRootComp, expectedErrno);
    return icalRootComp;
}

function stringToXml(session, data, expectedErrno) {
    if (!data || data.length == 0) { // assuming time-out
        throw new Components.Exception(errorToString(calIWcapErrors.WCAP_LOGIN_FAILED),
                                       calIWcapErrors.WCAP_LOGIN_FAILED);
    }
    var xml = getDomParser().parseFromString(data, "text/xml");
    checkWcapXmlErrno(xml, expectedErrno);
    return xml;
}

