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");
const path = require("path");

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

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

var throttle_output = 0;

var enabled = false;

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

// 404#0000245E00710186
// 019#02
// 050#9702

const current_id = (0x01 << 5) | can_conf.controller.id;
const brake_current_id = (0x02 << 5) | can_conf.controller.id;
const erpm_id = (0x20 << 5) | can_conf.controller.id;

function parseMap(filename) {
    let name = "";
    let map = [];

    return new Promise((resolve, reject) => {
        csv.parseFile(path.join(__dirname, map_conf.map_storage_path, filename), { comment: "#" })
            .on('error', error => reject(error))
            .on('data', row => map.push(row))
            .on('end', () => { name = filename; resolve([name, map]) });
    });
}

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;
}

(async () => {
    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);
    }

    if (fs.existsSync(path.join(__dirname, map_conf.map_storage_path, "selected"))) {
        const enabled_map_name = fs.readFileSync(path.join(__dirname, map_conf.map_storage_path, "selected"));
        [loaded_map_name, loaded_map_data] = await parseMap(enabled_map_name);
    }
})();

channel.addListener("onMessage", async function (message) {
    switch (message.id) {
        case can_conf.selector.id:
            if (Buffer.compare(message.data, can_conf.selector.command) == 0) {
                enabled = true;
            } else {
                enabled = false;
            }

            break;
        case can_conf.apps_id:
            const apps_percentage = ((message.data[1] << 8) | message.data[0]) / 1000;

            throttle_output = loaded_map_data[getMapIndex(map_throttle, apps_percentage)][2];

            break;
        case erpm_id:
            if (enabled) {
                if (fs.existsSync(path.join(__dirname, map_conf.map_storage_path, "selected"))) {
                    const enabled_map_name = fs.readFileSync(path.join(__dirname, map_conf.map_storage_path, "selected"));

                    if (enabled_map_name != "") {
                        if (loaded_map_name != enabled_map_name) {
                            [loaded_map_name, loaded_map_data] = await parseMap(enabled_map_name);
                        }

                        const ERPM = message.data[0] << 3 * 8 | message.data[1] << 2 * 8 | message.data[2] << 8 | message.data[3];

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

            break;
        default: {
            break;
        }
    }
});

channel.start();