const csv = require("fast-csv");
const fs = require("fs");
const path = require("path");
const uuid = require("uuid");
const map_conf = require("../config/map.conf");
const logger = require("./logger.util");

// Creates new map
async function addMap(filename, meta, throttle, motor) {
    var total = "";
    var map = [[[]]];

    // Get the new map metadata
    if (meta) {
        if ("name" in meta) {
            total += `#name:${meta["name"]}\n`;
        }
        if ("id" in meta) {
            total += `#id:${meta["id"]}\n`;
        }
        if ("description" in meta) {
            total += `#description:${meta["description"]}\n`;
        }
    }

    // Check if the required data has been received
    if (throttle && motor && ("0" in motor) && ("1" in motor)) {
        // Creating csv and storing it
        const throttle_values = Object.values(throttle);
        const current_values = Object.values(motor["0"]);
        const brake_values = Object.values(motor["1"]);

        for (let i = 0; i <= map_conf.steps; i++) {
            map[i] = [current_values[i], brake_values[i], throttle_values[i]];
        }
    }

    try {
        await csv.writeToString(map).then(data => total += data);
        fs.writeFileSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, filename), total);
    } catch (error) {
        throw new Error(error);
    }
}

// Update current map file
async function updateMap(filename, meta, throttle, motor) {
    // Get merged map comments and data
    var total = await generateComments(filename, meta);
    const map = await generateData(filename, throttle, motor);

    // Create and store file
    try {
        await csv.writeToString(map).then(data => total += data);
        fs.writeFileSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, filename), total);
        fs.renameSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, filename), path.join(path.dirname(require.main.filename), map_conf.map_storage_path, `${map_conf.prefix}_${uuid.v4()}.${map_conf.extension}`));
        if (fs.existsSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, "selected"))) {
            fs.unlinkSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, "selected"));
        }
    } catch (error) {
        throw new Error(error);
    }
}

// Merges data from a stored map and a new map
async function generateData(filename, throttle, motor) {
    const map = await parseMap(filename, 0);

    if (throttle) {
        const throttle_keys = Object.keys(throttle);
        for (k of throttle_keys) {
            map[k][2] = throttle[k];
        }
    }

    if (motor && ("0" in motor) && ("1" in motor)) {
        const current_keys = Object.keys(motor["0"]);
        for (k of current_keys) {
            map[k][0] = motor["0"][k];
        }

        const brake_keys = Object.keys(motor["1"]);
        for (k of brake_keys) {
            map[k][1] = motor["1"][k];
        }
    }

    return map;
}

// Merges comments from stored map and new map
async function generateComments(filename, meta) {
    const comments = await parseMapJson(filename, 1);
    var comment_string = "";

    if (meta) {
        if ("name" in meta) {
            comments["name"] = meta["name"];
        }

        if ("id" in meta) {
            comments["id"] = meta["id"];
        }

        if ("description" in meta) {
            comments["description"] = meta["description"];
        }

        for (k of Object.keys(comments)) {
            comment_string += `#${k}:${comments[k]}\n`;
        }
    }

    return comment_string;
}

// Check if a map exists
function mapExists(filename) {
    if (path.extname(filename) != ".csv") {
        return false;
    }
    return fs.existsSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, filename));
}

// Parse a map and returns it as array. On 1 returns comments on 0 returns data
function parseMap(filename, mode) {
    var result = [];

    return new Promise((resolve, reject) => {
        if (mode) {
            csv.parseFile(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, filename))
                .on('error', error => reject(error))
                .on('data', row => row[0][0] === "#" ? result.push(row[0].slice(1)) : resolve(result))
                .on('end', () => resolve(result));
        } else {
            csv.parseFile(path.join(path.dirname(require.main.filename), map_conf.map_storage_path, filename), { comment: "#" })
                .on('error', error => reject(error))
                .on('data', row => result.push(row))
                .on('end', () => resolve(result));
        }
    });
}

// Parse map data as JSON
async function parseMapJson(filename, mode) {
    const map = await parseMap(filename, mode);
    var json_map = {};

    if (mode) {
        if (map && map.length) {
            for (const m of map) {
                json_map[m.slice(0, m.indexOf(":")).toLowerCase()] = m.slice(m.indexOf(":") + 1)
            }
        }
    } else {
        for (let i = 0; i < map.length; i++) {
            json_map[i] = map[i]
        }
    }

    return json_map
}

// Get available map names in storage directory
async function getAvailableMaps() {
    var available_maps = {};

    try {
        var files = fs.readdirSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path));

        for (const file of files) {
            if (path.extname(file) == `.${map_conf.extension}`) {
                available_maps[file] = {};

                try {
                    let meta = await parseMap(file, 1);

                    if (meta && meta.length) {
                        for (const m of meta) {
                            available_maps[file][m.slice(0, m.indexOf(":")).toLowerCase()] = m.slice(m.indexOf(":") + 1)
                        }
                    }
                } catch (error) {
                    throw new Error(error);
                }
            }
        }
    } catch (error) {
        if (error.code === "ENOENT") {
            logger.info("No storage directory found. Creating directory.");
            fs.mkdirSync(path.join(path.dirname(require.main.filename), map_conf.map_storage_path));
        }
    }

    return available_maps;
}

module.exports = {
    getAvailableMaps,
    parseMap,
    parseMapJson,
    mapExists,
    updateMap,
    addMap
};