const can = require("socketcan");
const csv = require("fast-csv");
const fs = require("fs");

const can_conf = require("./app/config/can.conf");
const map_conf = require("./app/config/map.conf");

var map_rpm = [];
var map_throttle = [];

var loaded_map_name = "";
var loaded_map_data = [];

var throttle_output = 0;

var channel = can.createRawChannel(can_conf.network_id, true);

for (let i = 0; i <= map_conf.steps; i++) {
    map_rpm[i] = i * (map_conf.max_rpm / map_conf.steps);
    map_throttle[i] = i * (map_conf.max_throttle / map_conf.steps);
}

const current_id = (0x01 << 5) | can_conf.controller.id;
const brake_current_id = (0x02 << 5) | can_conf.controller.id;

function parseMap(filename) {
    loaded_map_data = [];

    return new Promise((resolve, reject) => {
        csv.parseFile(`app/storage/${filename}`, { comment: "#" })
            .on('error', error => reject(error))
            .on('data', row => loaded_map_data.push(row))
            .on('end', () => { loaded_map_name = filename; resolve() });
    });
}

function getMapIndex(array, input) {
    if (array.length === 0) {
        return -1;
    }

    let left = 0;
    let right = array.length - 1;

    while (left <= right) {
        const mid = Math.floor((left + right) / 2);

        if (array[mid] === input) {
            return mid;
        } else if (array[mid] < input) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }

    if (left >= array.length) {
        return array.length - 1;
    }
    if (right < 0) {
        return 0;
    }
    return Math.abs(array[left] - input) < Math.abs(array[right] - input) ? left : right;
}

channel.addListener("onMessage", async function (message) {
    if (fs.existsSync(map_conf.selected_map_path)) {
        let enabled_map_name = fs.readFileSync(map_conf.selected_map_path);

        if (enabled_map_name != "") {
            if (loaded_map_name != enabled_map_name) {
                await parseMap(enabled_map_name);
            }

            if (message.id == can_conf.apps_id) {
                const apps_percentage = ((message.data[1] << 8) | message.data[0]) / 1000;
                let pos = getMapIndex(map_throttle, apps_percentage);

                throttle_output = loaded_map_data[pos][2];
            } else {
                let packet_id = message.id >> 5;
                let node_id = message.id & 0x1F;

                if ((node_id == can_conf.controller.id) && (packet_id == 0x20)) {
                    let ERPM = message.data[0] << 3 * 8 | message.data[1] << 2 * 8 | message.data[2] << 8 | message.data[3];

                    if (throttle_output > 0) {
                        let max_current = loaded_map_data[getMapIndex(map_rpm, ERPM / can_conf.motor_poles)][0];
                        let current = throttle_output * max_current * 10;

                        channel.send({
                            id: current_id,
                            ext: false,
                            data: Buffer.from([(current >> 8) & 0xFF, current & 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF])
                        });
                    } else if (throttle_output < 0) {
                        let max_brake_current = loaded_map_data[getMapIndex(map_rpm, ERPM / can_conf.motor_poles)][1];
                        let brake_current = throttle_output * max_brake_current * 10;

                        channel.send({
                            id: brake_current_id,
                            ext: false,
                            data: Buffer.from([(brake_current >> 8) & 0xFF, brake_current & 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF])
                        });
                    } else {
                        channel.send({
                            id: current_id,
                            ext: false,
                            data: Buffer.from([0, 0, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF])
                        });
                    }
                }
            }
        }
    }
});

channel.start();