const pick = require('object.pick');
const LoopBackContext = require('loopback-context');

module.exports = function(Self) {
    Self.setup = function() {
        Self.super_.setup.call(this);
    };

/*     Self.observe('after save', async function(ctx) {
        const loopBackContext = LoopBackContext.getCurrentContext();
        await logInModel(ctx, loopBackContext);
    });

    Self.observe('before save', async function(ctx) {
        let oldInstance;
        let oldInstanceFk;
        let newInstance;
        if (ctx.data) {
            oldInstanceFk = pick(ctx.currentInstance, Object.keys(ctx.data));
            newInstance = await fkToValue(ctx.data, ctx);
            oldInstance = await fkToValue(oldInstanceFk, ctx);
        }
        if (ctx.isNewInstance) {
            newInstance = await fkToValue(ctx.instance.__data, ctx);
        }
        ctx.hookState.oldInstance = oldInstance;
        ctx.hookState.newInstance = newInstance;
    });

    Self.observe('before delete', async function(ctx) {
        let oldInstance;
        // console.log(ctx.where);
        if (ctx.where) {
            let affectedModel = ctx.Model.definition.name;
            // console.log(affectedModel);
            let deletedInstances = await Self.modelBuilder.models[affectedModel].find({where: ctx.where});
            // console.log(deletedInstances);

            let arrangedDeletedInstances = [];
            deletedInstances.forEach(async element => {
                console.log(element);
                arrangedDeletedInstances.push(await fkToValue(element, ctx));
            });

            console.log(arrangedDeletedInstances);
            // let deletedIntancesData = await fkToValue(deletedInstances, ctx);
            // console.log(deletedIntancesData);
            // oldInstanceFk = pick(ctx.currentInstance, Object.keys(ctx.data));
            // oldInstance = await fkToValue(oldInstanceFk, ctx);
        }
        ctx.hookState.oldInstance = oldInstance;
    });

    Self.observe('after delete', async function(ctx) {
        const loopBackContext = LoopBackContext.getCurrentContext();
        await logInModel(ctx, loopBackContext);
    }); */

    async function fkToValue(instance, ctx) {
        let result = {};
        for (let key in instance) {
            if (key == 'id') continue;
            let val = instance[key];
            console.log(val);
            if (val === undefined || val === null) continue;
            for (let key1 in ctx.Model.relations) {
                let val1 = ctx.Model.relations[key1];
                if (val1.keyFrom == key) {
                    let recordSet = await val1.modelTo.findById(val);
                    val = recordSet.name; // FIXME preparar todos los modelos con campo name
                    console.log(val);
                    break;
                }
            }
            result[key] = val;
        }
        // console.log(result);
        return result;
    }

    async function logInModel(ctx, loopBackContext) {
        let definition = ctx.Model.definition;
        let primaryKey;
        for (let property in definition.properties) {
            if (definition.properties[property].id) {
                primaryKey = property;
                break;
            }
        }

        if (!primaryKey) throw new Error('Primary key not found');
        let originId;

        // RELATIONS LOG
        let changedModelId;

        if (ctx.instance && !definition.settings.log.relation) {
            originId = ctx.instance.id;
            changedModelId = ctx.instance.id;
        } else if (definition.settings.log.relation) {
            primaryKey = ctx.Model.relations[definition.settings.log.relation].keyFrom;

            if (ctx.where && ctx.where[primaryKey])
                originId = ctx.where[primaryKey];
            else {
                originId = ctx.instance[primaryKey];
                changedModelId = ctx.instance.id;
            }
        } else {
            originId = ctx.currentInstance.id;
            changedModelId = ctx.currentInstance.id;
        }

        // console.log(ctx.instance, ctx.where, ctx.currentInstance);

        // Sets the changedModelValue to save and the instances changed in case its an updateAll
        let changedModelValue = definition.settings.log.changedModelValue;
        if (changedModelValue && (!ctx.instance || !ctx.instance[changedModelValue])) {
            var where = [];
            changedModelId = [];
            let changedInstances = await Self.modelBuilder.models[definition.name].find({where: ctx.where, fields: ['id', changedModelValue]});
            changedInstances.forEach(element => {
                where.push(element[changedModelValue]);
                changedModelId.push(element.id);
            });
        } else if (ctx.hookState.oldInstance) {
            where = ctx.instance[changedModelValue];
        }
        // console.log(where);

        // Set oldInstance, newInstance, userFk and action
        let oldInstance = {};
        if (ctx.hookState.oldInstance) {
            Object.assign(oldInstance, ctx.hookState.oldInstance);
        }

        let newInstance = {};
        if (ctx.hookState.newInstance) {
            Object.assign(newInstance, ctx.hookState.newInstance);
        }

        let userFk;
        if (loopBackContext)
            userFk = loopBackContext.active.accessToken.userId;

        let action = setActionType(ctx);

        let logRecord = {
            originFk: originId,
            userFk: userFk,
            action: action,
            changedModel: ctx.Model.definition.name,
            changedModelId: changedModelId,
            changedModelValue: where,
            oldInstance: oldInstance,
            newInstance: newInstance
        };

        let logsToSave = setLogsToSave(where, changedModelId, logRecord);

        let logModel = definition.settings.log.model;

        let transaction = {};
        if (ctx.options && ctx.options.transaction) {
            transaction = ctx.options.transaction;
        }

        // console.log(logsToSave);
        await Self.modelBuilder.models[logModel].create(logsToSave, transaction);
    }

    // this function retuns all the instances changed in case this is an updateAll
    function setLogsToSave(changedInstances, changedInstancesIds, logRecord) {
        let promises = [];
        if (changedInstances && typeof changedInstances == "object") {
            for (let i = 0; i < changedInstances.length; i++) {
                logRecord.changedModelId = changedInstancesIds[i];
                logRecord.changedModelValue = changedInstances[i];
                promises.push(JSON.parse(JSON.stringify(logRecord)));
            }
        } else {
            return logRecord;
        }
        return promises;
    }

    function setActionType(ctx) {
        let oldInstance = ctx.hookState.oldInstance;
        let newInstance = ctx.hookState.newInstance;

        if (oldInstance && newInstance) {
            return 'update';
        } else if (!oldInstance && newInstance) {
            return 'insert';
        }
        return 'delete';
    }
};