/**
 * Copyright JS Foundation and other contributors, http://js.foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/

var when = require("when");
var clone = require("clone");
var typeRegistry = require("@node-red/registry");
var Log;
var redUtil = require("@node-red/util").util;
var flowUtil = require("./util");

var nodeCloseTimeout = 15000;

class Flow {
    constructor(global,flow) {
        this.global = global;
        if (typeof flow === 'undefined') {
            this.flow = global;
        } else {
            this.flow = flow;
        }
        this.activeNodes = {};
        this.subflowInstanceNodes = {};
        this.catchNodeMap = {};
        this.statusNodeMap = {};
    }

    start(diff) {
        var node;
        var newNode;
        var id;
        this.catchNodeMap = {};
        this.statusNodeMap = {};

        var configNodes = Object.keys(this.flow.configs);
        var configNodeAttempts = {};
        while (configNodes.length > 0) {
            id = configNodes.shift();
            node = this.flow.configs[id];
            if (!this.activeNodes[id]) {
                var readyToCreate = true;
                // This node doesn't exist.
                // Check it doesn't reference another non-existent config node
                for (var prop in node) {
                    if (node.hasOwnProperty(prop) && prop !== 'id' && prop !== 'wires' && prop !== '_users' && this.flow.configs[node[prop]]) {
                        if (!this.activeNodes[node[prop]]) {
                            // References a non-existent config node
                            // Add it to the back of the list to try again later
                            configNodes.push(id);
                            configNodeAttempts[id] = (configNodeAttempts[id]||0)+1;
                            if (configNodeAttempts[id] === 100) {
                                throw new Error("Circular config node dependency detected: "+id);
                            }
                            readyToCreate = false;
                            break;
                        }
                    }
                }
                if (readyToCreate) {
                    newNode = createNode(node.type,node);
                    if (newNode) {
                        this.activeNodes[id] = newNode;
                    }
                }
            }
        }

        if (diff && diff.rewired) {
            for (var j=0;j<diff.rewired.length;j++) {
                var rewireNode = this.activeNodes[diff.rewired[j]];
                if (rewireNode) {
                    rewireNode.updateWires(this.flow.nodes[rewireNode.id].wires);
                }
            }
        }

        for (id in this.flow.nodes) {
            if (this.flow.nodes.hasOwnProperty(id)) {
                node = this.flow.nodes[id];
                if (!node.subflow) {
                    if (!this.activeNodes[id]) {
                        newNode = createNode(node.type,node);
                        if (newNode) {
                            this.activeNodes[id] = newNode;
                        }
                    }
                } else {
                    if (!this.subflowInstanceNodes[id]) {
                        try {
                            var subflowDefinition = this.flow.subflows[node.subflow]||this.global.subflows[node.subflow]
                            var nodes = createSubflow(subflowDefinition,node,this.flow.subflows,this.global.subflows,this.activeNodes);
                            this.subflowInstanceNodes[id] = nodes.map(function(n) { return n.id});
                            for (var i=0;i<nodes.length;i++) {
                                if (nodes[i]) {
                                    this.activeNodes[nodes[i].id] = nodes[i];
                                }
                            }
                        } catch(err) {
                            console.log(err.stack)
                        }
                    }
                }
            }
        }

        for (id in this.activeNodes) {
            if (this.activeNodes.hasOwnProperty(id)) {
                node = this.activeNodes[id];
                if (node.type === "catch") {
                    this.catchNodeMap[node.z] = this.catchNodeMap[node.z] || [];
                    this.catchNodeMap[node.z].push(node);
                } else if (node.type === "status") {
                    this.statusNodeMap[node.z] = this.statusNodeMap[node.z] || [];
                    this.statusNodeMap[node.z].push(node);
                }
            }
        }
    }

    stop(stopList, removedList) {
        return new Promise((resolve,reject) => {
            var i;
            if (stopList) {
                for (i=0;i<stopList.length;i++) {
                    if (this.subflowInstanceNodes[stopList[i]]) {
                        // The first in the list is the instance node we already
                        // know about
                        stopList = stopList.concat(this.subflowInstanceNodes[stopList[i]].slice(1))
                    }
                }
            } else {
                stopList = Object.keys(this.activeNodes);
            }
            // Convert the list to a map to avoid multiple scans of the list
            var removedMap = {};
            removedList = removedList || [];
            removedList.forEach(function(id) {
                removedMap[id] = true;
            });

            var promises = [];
            for (i=0;i<stopList.length;i++) {
                var node = this.activeNodes[stopList[i]];
                if (node) {
                    delete this.activeNodes[stopList[i]];
                    if (this.subflowInstanceNodes[stopList[i]]) {
                        delete this.subflowInstanceNodes[stopList[i]];
                    }
                    try {
                        var removed = removedMap[stopList[i]];
                        promises.push(
                            when.promise(function(resolve, reject) {
                                var start;
                                var nt = node.type;
                                var nid = node.id;
                                var n = node;
                                when.promise(function(resolve) {
                                    Log.trace("Stopping node "+nt+":"+nid+(removed?" removed":""));
                                    start = Date.now();
                                    resolve(n.close(removed));
                                }).timeout(nodeCloseTimeout).then(function(){
                                    var delta = Date.now() - start;
                                    Log.trace("Stopped node "+nt+":"+nid+" ("+delta+"ms)" );
                                    resolve(delta);
                                },function(err) {
                                    var delta = Date.now() - start;
                                    n.error(Log._("nodes.flows.stopping-error",{message:err}));
                                    Log.debug(err.stack);
                                    reject(err);
                                });
                            })
                        );
                    } catch(err) {
                        node.error(err);
                    }
                }
            }
            when.settle(promises).then(function(results) {
                resolve();
            });
        });
    }

    update(_global,_flow) {
        this.global = _global;
        this.flow = _flow;
    }

    getNode(id) {
        return this.activeNodes[id];
    }

    getActiveNodes() {
        return this.activeNodes;
    }

    handleStatus(node,statusMessage) {
        var targetStatusNodes = null;
        var reportingNode = node;
        var handled = false;
        while (reportingNode && !handled) {
            targetStatusNodes = this.statusNodeMap[reportingNode.z];
            if (targetStatusNodes) {
                targetStatusNodes.forEach(function(targetStatusNode) {
                    if (targetStatusNode.scope && targetStatusNode.scope.indexOf(node.id) === -1) {
                        return;
                    }
                    var message = {
                        status: {
                            text: "",
                            source: {
                                id: node.id,
                                type: node.type,
                                name: node.name
                            }
                        }
                    };
                    if (statusMessage.hasOwnProperty("text")) {
                        message.status.text = statusMessage.text.toString();
                    }
                    targetStatusNode.receive(message);
                    handled = true;
                });
            }
            if (!handled) {
                reportingNode = this.activeNodes[reportingNode.z];
            }
        }
    }

    handleError(node,logMessage,msg) {
        var count = 1;
        if (msg && msg.hasOwnProperty("error") && msg.error !== null) {
            if (msg.error.hasOwnProperty("source") && msg.error.source !== null) {
                if (msg.error.source.id === node.id) {
                    count = msg.error.source.count+1;
                    if (count === 10) {
                        node.warn(Log._("nodes.flow.error-loop"));
                        return false;
                    }
                }
            }
        }
        var targetCatchNodes = null;
        var throwingNode = node;
        var handled = false;
        while (throwingNode && !handled) {
            targetCatchNodes = this.catchNodeMap[throwingNode.z];
            if (targetCatchNodes) {
                targetCatchNodes.forEach(function(targetCatchNode) {
                    if (targetCatchNode.scope && targetCatchNode.scope.indexOf(throwingNode.id) === -1) {
                        return;
                    }
                    var errorMessage;
                    if (msg) {
                        errorMessage = redUtil.cloneMessage(msg);
                    } else {
                        errorMessage = {};
                    }
                    if (errorMessage.hasOwnProperty("error")) {
                        errorMessage._error = errorMessage.error;
                    }
                    errorMessage.error = {
                        message: logMessage.toString(),
                        source: {
                            id: node.id,
                            type: node.type,
                            name: node.name,
                            count: count
                        }
                    };
                    if (logMessage.hasOwnProperty('stack')) {
                        errorMessage.error.stack = logMessage.stack;
                    }
                    targetCatchNode.receive(errorMessage);
                    handled = true;
                });
            }
            if (!handled) {
                throwingNode = this.activeNodes[throwingNode.z];
            }
        }
        return handled;
    }
}

/**
 * Create a new instance of a node
 * @param  {string} type   The node type string
 * @param  {object} config The node configuration object
 * @return {Node}          The instance of the node
 */
function createNode(type,config) {
    var newNode = null;
    try {
        var nodeTypeConstructor = typeRegistry.get(type);
        if (nodeTypeConstructor) {
            var conf = clone(config);
            delete conf.credentials;
            for (var p in conf) {
                if (conf.hasOwnProperty(p)) {
                    flowUtil.mapEnvVarProperties(conf,p);
                }
            }
            try {
                newNode = new nodeTypeConstructor(conf);
            } catch (err) {
                Log.log({
                    level: Log.ERROR,
                    id:conf.id,
                    type: type,
                    msg: err
                });
            }
        } else {
            Log.error(Log._("nodes.flow.unknown-type", {type:type}));
        }
    } catch(err) {
        Log.error(err);
    }
    return newNode;
}

function createSubflow(sf,sfn,subflows,globalSubflows,activeNodes) {
    //console.log("CREATE SUBFLOW",sf.id,sfn.id);
    var nodes = [];
    var node_map = {};
    var newNodes = [];
    var node;
    var wires;
    var i,j,k;

    var createNodeInSubflow = function(def) {
        node = clone(def);
        var nid = redUtil.generateId();
        node_map[node.id] = node;
        node._alias = node.id;
        node.id = nid;
        node.z = sfn.id;
        newNodes.push(node);
    }

    // Clone all of the subflow config node definitions and give them new IDs
    for (i in sf.configs) {
        if (sf.configs.hasOwnProperty(i)) {
            createNodeInSubflow(sf.configs[i]);
        }
    }
    // Clone all of the subflow node definitions and give them new IDs
    for (i in sf.nodes) {
        if (sf.nodes.hasOwnProperty(i)) {
            createNodeInSubflow(sf.nodes[i]);
        }
    }

    // Look for any catch/status nodes and update their scope ids
    // Update all subflow interior wiring to reflect new node IDs
    for (i=0;i<newNodes.length;i++) {
        node = newNodes[i];
        if (node.wires) {
            var outputs = node.wires;
            for (j=0;j<outputs.length;j++) {
                wires = outputs[j];
                for (k=0;k<wires.length;k++) {
                    outputs[j][k] = node_map[outputs[j][k]].id
                }
            }
            if ((node.type === 'catch' || node.type === 'status') && node.scope) {
                node.scope = node.scope.map(function(id) {
                    return node_map[id]?node_map[id].id:""
                })
            } else {
                for (var prop in node) {
                    if (node.hasOwnProperty(prop) && prop !== '_alias') {
                        if (node_map[node[prop]]) {
                            //console.log("Mapped",node.type,node.id,prop,node_map[node[prop]].id);
                            node[prop] = node_map[node[prop]].id;
                        }
                    }
                }
            }
        }
    }

    // Create a subflow node to accept inbound messages and route appropriately
    var Node = require("../Node");
    var subflowInstance = {
        id: sfn.id,
        type: sfn.type,
        z: sfn.z,
        name: sfn.name,
        wires: []
    }
    if (sf.in) {
        subflowInstance.wires = sf.in.map(function(n) { return n.wires.map(function(w) { return node_map[w.id].id;})})
        subflowInstance._originalWires = clone(subflowInstance.wires);
    }
    var subflowNode = new Node(subflowInstance);

    subflowNode.on("input", function(msg) { this.send(msg);});


    subflowNode._updateWires = subflowNode.updateWires;

    subflowNode.updateWires = function(newWires) {
        // Wire the subflow outputs
        if (sf.out) {
            var node,wires,i,j;
            // Restore the original wiring to the internal nodes
            subflowInstance.wires = clone(subflowInstance._originalWires);
            for (i=0;i<sf.out.length;i++) {
                wires = sf.out[i].wires;
                for (j=0;j<wires.length;j++) {
                    if (wires[j].id != sf.id) {
                        node = node_map[wires[j].id];
                        if (node._originalWires) {
                            node.wires = clone(node._originalWires);
                        }
                    }
                }
            }

            var modifiedNodes = {};
            var subflowInstanceModified = false;

            for (i=0;i<sf.out.length;i++) {
                wires = sf.out[i].wires;
                for (j=0;j<wires.length;j++) {
                    if (wires[j].id === sf.id) {
                        subflowInstance.wires[wires[j].port] = subflowInstance.wires[wires[j].port].concat(newWires[i]);
                        subflowInstanceModified = true;
                    } else {
                        node = node_map[wires[j].id];
                        node.wires[wires[j].port] = node.wires[wires[j].port].concat(newWires[i]);
                        modifiedNodes[node.id] = node;
                    }
                }
            }
            Object.keys(modifiedNodes).forEach(function(id) {
                var node = modifiedNodes[id];
                subflowNode.instanceNodes[id].updateWires(node.wires);
            });
            if (subflowInstanceModified) {
                subflowNode._updateWires(subflowInstance.wires);
            }
        }
    }

    nodes.push(subflowNode);

    // Wire the subflow outputs
    if (sf.out) {
        var modifiedNodes = {};
        for (i=0;i<sf.out.length;i++) {
            wires = sf.out[i].wires;
            for (j=0;j<wires.length;j++) {
                if (wires[j].id === sf.id) {
                    // A subflow input wired straight to a subflow output
                    subflowInstance.wires[wires[j].port] = subflowInstance.wires[wires[j].port].concat(sfn.wires[i])
                    subflowNode._updateWires(subflowInstance.wires);
                } else {
                    node = node_map[wires[j].id];
                    modifiedNodes[node.id] = node;
                    if (!node._originalWires) {
                        node._originalWires = clone(node.wires);
                    }
                    node.wires[wires[j].port] = (node.wires[wires[j].port]||[]).concat(sfn.wires[i]);
                }
            }
        }
    }

    // Instantiate the nodes
    for (i=0;i<newNodes.length;i++) {
        node = newNodes[i];
        var type = node.type;

        var m = /^subflow:(.+)$/.exec(type);
        if (!m) {
            var newNode = createNode(type,node);
            if (newNode) {
                activeNodes[node.id] = newNode;
                nodes.push(newNode);
            }
        } else {
            var subflowId = m[1];
            nodes = nodes.concat(createSubflow(subflows[subflowId]||globalSubflows[subflowId],node,subflows,globalSubflows,activeNodes));
        }
    }

    subflowNode.instanceNodes = {};

    nodes.forEach(function(node) {
        subflowNode.instanceNodes[node.id] = node;
    });
    return nodes;
}


module.exports = {
    init: function(runtime) {
        nodeCloseTimeout = runtime.settings.nodeCloseTimeout || 15000;
        Log = runtime.log;
    },
    create: function(global,conf) {
        return new Flow(global,conf);
    }
}