// Debug
const { DebugBuilder } = require("../utilities/debugBuilder.js");
const log = new DebugBuilder("client", "radioController");
// Modules 
const { resolve, dirname } = require('path');
const fs = require('fs');
const radioConfig = require('../config/clientConfig').radioAppConfig;
const radioConfigHelper = require("../utilities/radioConfigHelper");
const presetWrappers = require("../utilities/updatePresets");
const spawn = require('child_process').spawn;
const converter = require("convert-units");

let radioChildProcess, tempRes, radioConfigPath;

/**
 * Closes the radio executable if it's in one
 */
exports.closeRadioSession = (req, res) => {
    if (!radioChildProcess) return res.sendStatus(200)
    tempRes = res;
    radioChildProcess.kill();
    radioChildProcess = undefined;
}

/**
 * Change the current 'cfg.json' file to the preset specified
 * @param {string} presetName 
 */
exports.changeCurrentConfig = (req, res) => {
    // Check if the given config is saved
    log.DEBUG("[/radio/changeCurrentConfig] - Checking if provided preset is in the config");
    if (!checkIfPresetExists(req.body.presetName)) return res.status(500).JSON("No preset with given name found in config"); // No preset with the given name is in the config

    // Check if the current config is the same as the preset given
    const currentConfig = readOP25Config();
    if (currentConfig.channels && currentConfig.channels.name === req.body.presetName) {
        log.DEBUG("[/radio/changeCurrentConfig] - Current config is the same as the preset given");
        return res.sendStatus(202);
    }

    // Convert radioPreset to OP25 'cfg.json. file
    log.DEBUG("[/radio/changeCurrentConfig] - Converting radioPreset to OP25 config");
    const updatedConfigObject = convertRadioPresetsToOP25Config(req.body.presetName);

    // Replace current JSON file with the updated file
    writeOP25Config(updatedConfigObject, () => {
        res.sendStatus(200);
    })    
}

/**
 * Open a new OP25 process tuned to the specified system
 */
exports.openRadioSession = () => {
    if (radioChildProcess) closeRadioSession();
    radioChildProcess = spawn(getRadioBinPath());
}

/**
 * Get the location of the 'multi_rx.py' binary from the config
 */
function getRadioBinPath(){
    return resolve(radioConfig.bin);
}

/**
 * Write the given config to the JSON file in OP25 the bin dir
 * @param config The full config to be written to the file
 * @param {function} callback The function to be called when this wrapper completes
 */
function writeOP25Config(config, callback = undefined) {
    log.DEBUG("Updating OP25 config with: ", config);    
    fs.writeFile(getRadioConfigPath(), JSON.stringify(config), (err) => {
        // Error checking
        if (err) {
            log.ERROR(err);
            throw err;
        }
        log.DEBUG("Write Complete");
        if (callback) callback()
    });
}

/**
 * Get the current config file in use by OP25
 * @returns {object|*} The parsed config object currently set in OP25
 */
function readOP25Config() {
    const configPath = getRadioConfigPath();
    log.DEBUG(`Reading from config path: '${configPath}'`);    
    return JSON.parse(fs.readFileSync(configPath));
}

/**
 * Get the path of the config for the radio app (OP25) and set the global variable
 */
function getRadioConfigPath(){
    let radioConfigDirPath = dirname(getRadioBinPath());    
    return resolve(`${radioConfigDirPath}/cfg.json`);
}

/**
 * Check to see if the preset name exists in the config
 * @param {string} presetName The system name as saved in the preset
 * @returns {true||false}
 */
function checkIfPresetExists(presetName) {
    const savedPresets = presetWrappers.getPresets();
    if (!Object.keys(savedPresets).includes(presetName)) return false;
    else return true;
}

/**
 * Convert a radioPreset to OP25's cfg.json file
 */
function convertRadioPresetsToOP25Config(presetName){
    const savedPresets = presetWrappers.getPresets();
    let frequencyString = "";
    for (const frequency of savedPresets[presetName].frequencies){
        frequencyString += `${converter(frequency).from("Hz").to("MHz")},`
    }
    frequencyString = frequencyString.slice(0, -1);

    let updatedOP25Config;
    switch (savedPresets[presetName].mode){
        case "p25":
            updatedOP25Config = new radioConfigHelper.P25({
                "systemName": presetName, 
                "controlChannelsString": frequencyString, 
                "tagsFile": savedPresets[presetName].trunkFile
            });
            break;
        case "nbfm":
            //code for nbfm here
            updatedOP25Config = new radioConfigHelper.NBFM({
                "frequency": frequencyString,
                "systemName": presetName
            });
            break;
        default:
            throw new Error("Radio mode of selected preset not recognized");
    }

    log.DEBUG(updatedOP25Config);
    return updatedOP25Config;
}