const Transaction = require("../models/transaction");
const Merchant = require("../models/merchant");

const helper = require("./helper.js");

const ObjectId = require("mongoose").Types.ObjectId;
const xlsx = require("xlsx");
const fs = require("fs");

module.exports = {
    /*
    POST - retrieves a list of transactions based on the filter
    req.body = {
        startDate: starting date to filter on,
        endDate: ending date to filter on,
        recipes: list of recipes to filter on
    }
    NOTE: May be a good idea to search recipes with for looping rather than query
        Needs some testing and playing with if so
    */
    getTransactions: function(req, res){
        if(!req.session.user){
            req.session.error = "MUST BE LOGGED IN TO DO THAT";
            return res.redirect("/");
        }

        let objectifiedRecipes = [];
        for(let i = 0; i < req.body.recipes.length; i++){
            objectifiedRecipes.push(new ObjectId(req.body.recipes[i]));
        }
        let startDate = new Date(req.body.startDate);
        let endDate = new Date(req.body.endDate);
        endDate.setDate(endDate.getDate() + 1);

        Transaction.aggregate([
            {$match: {
                merchant: ObjectId(req.session.user),
                date: {
                    $gte: startDate,
                    $lt: endDate
                },
                recipes: {
                    $elemMatch: {
                        recipe: {
                            $in: objectifiedRecipes
                        }
                    }
                }
            }},
            {$sort: {date: -1}}
        ])
            .then((transactions)=>{
                return res.json(transactions);
            })
            .catch((err)=>{
                return res.json("ERROR: UNABLE TO RETRIEVE YOUR TRANSACTIONS");
            });
    },

    /*
    POST - create a new transaction
    req.body = {
        date: date of the transaction,
        recipes: [{
            recipe: id of the recipe to add,
            quantity: quantity of the recipe sold (in main unit),
        }]
        ingredientUpdates: an object that contains all of the ingredients that
            need to be updated as well as the amount to change. 
            keys = id
            values = quantity to change in grams
    }
    */
    createTransaction: function(req, res){
        if(!req.session.user){
            req.session.error = "MUST BE LOGGED IN TO DO THAT";
            return res.redirect("/");
        }

        let newTransaction = new Transaction({
            merchant: req.session.user,
            date: new Date(req.body.date),
            device: "none",
            recipes: req.body.recipes
        });

        helper.updateIngredientQuantities(req.body.ingredientUpdates, req.session.user);

        newTransaction.save()
            .then((response)=>{
                return res.json(response);
            })
            .catch((err)=>{
                if(typeof(err) === "string"){
                    return res.json(err);
                }
                if(err.name === "ValidationError"){
                    return res.json(err.errors.name.properties.message);
                }
                return res.json("ERROR: UNABLE TO CREATE NEW TRANSACTION");
            });
    },

    createFromSpreadsheet: function(req, res){
        if(!req.session.user){
            req.session.error = "MUST BE LOGGED IN TO DO THAT";
            return res.redirect("/");
        }

        //read file, get the correct sheet, create array from sheet
        let workbook = xlsx.readFile(req.file.path);
        fs.unlink(req.file.path, ()=>{});

        let sheets = Object.keys(workbook.Sheets);
        let sheet = {};
        for(let i = 0; i < sheets.length; i++){
            let str = sheets[i].toLowerCase();
            if(str === "transaction" || str === "transactions"){
                sheet = workbook.Sheets[sheets[i]];
            }
        }

        const array = xlsx.utils.sheet_to_json(sheet, {
            header: 1
        });

        let locations = {};
        for(let i = 0; i < array[0].length; i++){
            if(array[0][i] === undefined){
                continue;
            }

            switch(array[0][i].toLowerCase()){
                case "date": locations.date = i; break;
                case "recipes": locations.recipes = i; break;
                case "quantity": locations.quantity = i; break;
            }
        }

        Merchant.findOne({_id: req.session.user})
            .populate("recipes")
            .populate("inventory.ingredient")
            .then((merchant)=>{
                let transaction = new Transaction({
                    merchant: req.session.user,
                    recipes: []
                });

                if(array[1][0] === undefined){
                    transaction.date = new Date();
                }else{
                    transaction.date = new Date(array[1][0]);
                }
                
                let ingredients = [];
                for(let i = 1; i < array.length; i++){
                    if(array[i][locations.recipes] === undefined || array[i][locations.quantity === 0]){
                        continue;
                    }

                    let exists = false;
                    for(let j = 0; j < merchant.recipes.length; j++){
                        if(merchant.recipes[j].name.toLowerCase() === array[i][locations.recipes].toLowerCase()){
                            transaction.recipes.push({
                                recipe: merchant.recipes[j],
                                quantity: array[i][locations.quantity]
                            });

                            for(let k = 0; k < merchant.recipes[j].ingredients.length; k++){
                                ingredients.push({
                                    id: merchant.recipes[j].ingredients[k].ingredient,
                                    quantity: array[i][locations.quantity] * merchant.recipes[j].ingredients[k].quantity
                                });
                            }

                            exists = true;
                            break;
                        }
                    }

                    if(exists !== true){
                        throw `COULD NOT FIND RECIPE ${array[i][locations.recipes]}`;
                    }
                }

                for(let i = 0; i < ingredients.length; i++){
                    for(let j = 0; j < merchant.inventory.length; j++){
                        
                        if(merchant.inventory[j].ingredient._id.toString() === ingredients[i].id.toString()){
                            merchant.inventory[j].quantity -= ingredients[i].quantity;

                            break;
                        }
                    }
                }

                return Promise.all([transaction.save(), merchant.save()]);
            })
            .then((response)=>{
                return res.json(response[0]);
            })
            .catch((err)=>{
                if(typeof(err) === "string"){
                    return res.json(err);
                }
                if(err.name === "ValidationError"){
                    return res.json(err.errors.name.properties.message);
                }
                return res.json("ERROR: UNABLE TO CREATE YOUR TRANSACTION");
            });
    },

    spreadsheetTemplate: function(req, res){
        if(!req.session.user){
            req.session.error = "MUST BE LOGGED IN TO DO THAT";
            return res.redirect("/");
        }

        Merchant.findOne({_id: req.session.user})
            .populate("recipes")
            .then((merchant)=>{
                let workbook = xlsx.utils.book_new();
                workbook.SheetNames.push("Transaction");
                let workbookData = [];
                let now = new Date().toISOString();

                workbookData.push(["Date", "Recipes", "Quantity"]);
                workbookData.push([now.slice(0, 10), merchant.recipes[0].name, 0]);

                for(let i = 1; i < merchant.recipes.length; i++){
                    workbookData.push(["", merchant.recipes[i].name, 0]);
                }

                workbook.Sheets.Transaction = xlsx.utils.aoa_to_sheet(workbookData);
                xlsx.writeFile(workbook, "SublineTransaction.xlsx");
                return res.download("SublineTransaction.xlsx", (err)=>{
                    fs.unlink("SublineTransaction.xlsx", ()=>{});
                });
            })
            .catch((err)=>{});
    },

    /*
    DELETE - Remove a transaction from the database
    */
    remove: function(req, res){
        if(!req.session.user){
            req.session.error = "MUST BE LOGGED IN TO DO THAT";
            return res.redirect("/");
        }

        let merchant = {};
        let transaction = {};
        Merchant.findOne({_id: req.session.user})
            .then((response)=>{
                merchant = response;
                return Transaction.findOne({_id: req.params.id}).populate("recipes.recipe");
            })
            .then((response)=>{
                transaction = response;
                return Transaction.deleteOne({_id: req.params.id});
            })
            .then((response)=>{
                res.json();

                for(let i = 0; i < transaction.recipes.length; i++){
                    const recipe = transaction.recipes[i].recipe;
                    for(let j = 0; j < recipe.ingredients.length; j++){
                        const ingredient = recipe.ingredients[j].ingredient;
                        for(let k = 0; k < merchant.inventory.length; k++){
                            if(ingredient.toString() === merchant.inventory[k].ingredient.toString()){
                                merchant.inventory[k].quantity += recipe.ingredients[j].quantity * transaction.recipes[i].quantity;
                                break;
                            }
                        }
                    }
                }

                return merchant.save();
            })
            .catch((err)=>{
                if(typeof(err) === "string"){
                    return res.json(err);
                }
                if(err.name === "ValidationError"){
                    return res.json(err.errors.name.properties.message);
                }
                return res.json("ERROR: UNABLE TO DELETE THE TRANSACTION");
            });
    },

    /*
    GET - get transactions between two dates, sorted and group by date
    params:
        from: Date string
        to: Date string
    return:
        [{
            date: Date
            transactions:[[Recipe]]
        }]
    */
    getTransactionsByDate: function(req, res){
        if(!req.session.user){
            req.session.error = "MUST BE LOGGED IN TO DO THAT";
            return res.redirect("/");
        }

        const from = new Date(req.params.from);
        const to = new Date(req.params.to);
        to.setDate(to.getDate() + 1);

        Transaction.aggregate([
            {$match: {
                merchant: ObjectId(req.session.user),
                date: {
                    $gte: from,
                    $lt: to
                }
            }},
            {$group: {
                _id: {$function: {
                    body: "function(year, month, date){return `${year}-${month}-${date}`;}",
                    args: [{$year: "$date"}, {$month: "$date"}, {$dayOfMonth: "$date"}],
                    lang: "js"
                }},
                transactions: {$push: {
                    _id: "$_id",
                    recipes: "$recipes"
                }}
            }},
            {$project: {
                _id: 0,
                date: {$convert: {
                    input: "$_id",
                    to: "date"
                }},
                transactions: 1
            }},
            {$sort: {
                date: 1
            }}
        ])
            .then((transactions)=>{
                return res.json(transactions);
            })
            .catch((err)=>{
                return res.json("ERROR: UNABLE TO RETRIEVE DATA");
            });
    },

    /*
    GET - Creates 5000 transactions for logged in merchant for testing
    */
    populate: function(req, res){
        if(!req.session.user){
            res.session.error = "Must be logged in to do that";
            return res.redirect("/");
        }

        function randomDate() {
            let now = new Date();
            let start = new Date();
            start.setFullYear(now.getFullYear() - 1);
            return new Date(start.getTime() + Math.random() * (now.getTime() - start.getTime()));
        }

        Merchant.findOne({_id: req.session.user})
            .then((merchant)=>{
                let newTransactions = [];

                for(let i = 0; i < 5000; i++){
                    let newTransaction = new Transaction({
                        merchant: merchant._id,
                        date: randomDate(),
                        recipes: []
                    });

                    let numberOfRecipes = Math.floor((Math.random() * 5) + 1);

                    for(let j = 0; j < numberOfRecipes; j++){
                        let recipeNumber = Math.floor(Math.random() * merchant.recipes.length);
                        let randQuantity = Math.floor((Math.random() * 3) + 1);

                        newTransaction.recipes.push({
                            recipe: merchant.recipes[recipeNumber],
                            quantity: randQuantity
                        });
                    }

                    newTransactions.push(newTransaction);
                }

                Transaction.create(newTransactions)
                    .then((transactions)=>{
                        return res.redirect("/dashboard");
                    })
                    .catch((err)=>{
                        return;
                    });
            })
            .catch((err)=>{
                return;
            });
    }
}