/**
 * 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.
 **/

/**
 * @namespace RED.context
 */

var runtime;

// TODO: move runtime/util to util/index
var util = require("@node-red/util").util;

function exportContextStore(scope,ctx, store, result, callback) {
    ctx.keys(store,function(err, keys) {
        if (err) {
            return callback(err);
        }
        result[store] = {};
        var c = keys.length;
        if (c === 0) {
            callback(null);
        } else {
            keys.forEach(function(key) {
                ctx.get(key,store,function(err, v) {
                    if (err) {
                        return callback(err);
                    }
                    if (scope !== 'global' ||
                        store === runtime.nodes.listContextStores().default ||
                            !runtime.settings.hasOwnProperty("functionGlobalContext") ||
                            !runtime.settings.functionGlobalContext.hasOwnProperty(key) ||
                            runtime.settings.functionGlobalContext[key] !== v) {
                                result[store][key] = util.encodeObject({msg:v});
                    }
                    c--;
                    if (c === 0) {
                        callback(null);
                    }
                });
            });
        }
    });
}


var api = module.exports = {
    init: function(_runtime) {
        runtime = _runtime;
    },
    /**
    * Gets the info of an individual node set
    * @param {Object} opts
    * @param {User} opts.user - the user calling the api
    * @param {String} opts.scope - the scope of the context
    * @param {String} opts.id - the id of the context
    * @param {String} opts.store - the context store
    * @param {String} opts.key - the context key

    * @return {Promise} - the node information
    * @memberof RED.nodes
    */
    getValue: function(opts) {
        return new Promise(function(resolve,reject) {
            var scope = opts.scope;
            var id = opts.id;
            var store = opts.store;
            var key = opts.key;

            var availableStores = runtime.nodes.listContextStores();
            //{ default: 'default', stores: [ 'default', 'file' ] }
            if (store && availableStores.stores.indexOf(store) === -1) {
                runtime.log.audit({event: "context.get",scope:scope,id:id,store:store,key:key,error:"not_found"});
                var err = new Error();
                err.code = "not_found";
                err.status = 404;
                return reject(err);
            }
            var ctx;
            if (scope === 'global') {
                ctx = runtime.nodes.getContext('global');
            } else if (scope === 'flow') {
                ctx = runtime.nodes.getContext(id);
            } else if (scope === 'node') {
                var node = runtime.nodes.getNode(id);
                if (node) {
                    ctx = node.context();
                }
            }
            if (ctx) {
                if (key) {
                    store = store || availableStores.default;
                    ctx.get(key,store,function(err, v) {
                        var encoded = util.encodeObject({msg:v});
                        if (store !== availableStores.default) {
                            encoded.store = store;
                        }
                        runtime.log.audit({event: "context.get",scope:scope,id:id,store:store,key:key});
                        resolve(encoded);
                    });
                    return;
                } else {
                    var stores;
                    if (!store) {
                        stores = availableStores.stores;
                    } else {
                        stores = [store];
                    }

                    var result = {};
                    var c = stores.length;
                    var errorReported = false;
                    stores.forEach(function(store) {
                        exportContextStore(scope,ctx,store,result,function(err) {
                            if (err) {
                                // TODO: proper error reporting
                                if (!errorReported) {
                                    errorReported = true;
                                    runtime.log.audit({event: "context.get",scope:scope,id:id,store:store,key:key,error:"unexpected_error"});
                                    var err = new Error();
                                    err.code = "unexpected_error";
                                    err.status = 400;
                                    return reject(err);
                                }

                                return;
                            }
                            c--;
                            if (c === 0) {
                                if (!errorReported) {
                                    runtime.log.audit({event: "context.get",scope:scope,id:id,store:store,key:key});
                                    resolve(result);
                                }
                            }
                        });
                    })
                }
            } else {
                runtime.log.audit({event: "context.get",scope:scope,id:id,store:store,key:key});
                resolve({});
            }
        })
    }
}