const fss = require('fs');
const yargs = require('yargs');
const hide_bin = require('yargs/helpers').hideBin; //eslint-disable-line snakecasejs/snakecasejs
const Logger = require('logplease');
const logger = Logger.create('config');
const yaml = require('js-yaml');

const header = `#
#      ____  _     _              
#     |  _ \\(_)___| |_ ___  _ __  
#     | |_) | / __| __/ _ \\| '_ \\ 
#     |  __/| \\__ \\ || (_) | | | |
#     |_|   |_|___/\\__\\___/|_| |_|
#
# A High performance code execution engine                   
#     github.com/engineer-man/piston
#

`;
const argv = yargs(hide_bin(process.argv))
    .usage('Usage: $0 -c [config]')
    .demandOption('c') //eslint-disable-line snakecasejs/snakecasejs
    .option('config', {
        alias: 'c',
        describe: 'config file to load from',
        default: '/piston/config.yaml'
    })
    .option('make-config', {
        alias: 'm',
        type: 'boolean',
        describe: 'create config file and populate defaults if it does not already exist'
    }).argv;


const options = [
    {
        key: 'log_level',
        desc: 'Level of data to log',
        default: 'INFO',
        /* eslint-disable snakecasejs/snakecasejs */
        options: Object.values(Logger.LogLevels),
        validators: [x=>Object.values(Logger.LogLevels).includes(x) || `Log level ${x} does not exist`]
        /* eslint-enable snakecasejs/snakecasejs */
    },
    {
        key: 'bind_address',
        desc: 'Address to bind REST API on\nThank @Bones for the number',
        default: '0.0.0.0:6969',
        validators: []
    },
    {
        key: 'data_directory',
        desc: 'Absolute path to store all piston related data at',
        default: '/piston',
        validators: [x=> fss.exists_sync(x) || `Directory ${x} does not exist`]
    },
    {
        key: 'cache_ttl',
        desc: 'Time in milliseconds to keep data in cache for at a maximum',
        default: 60 * 60 * 1000,
        validators: []
    },
    {
        key: 'cache_flush_time',
        desc: 'Interval in milliseconds to flush cache to disk at',
        default: 90 * 60 * 1000, //90 minutes
        validators: []
    },
    {
        key: 'state_flush_time',
        desc: 'Interval in milliseconds to flush state to disk at',
        default: 5000, // 5 seconds (file is tiny)
        validators: []
    },
    {
        key: 'runner_uid_min',
        desc: 'Minimum uid to use for runner',
        default: 1000,
        validators: []
    },
    {
        key: 'runner_uid_max',
        desc: 'Maximum uid to use for runner',
        default: 1500,
        validators: []
    },
    {
        key: 'runner_gid_min',
        desc: 'Minimum gid to use for runner',
        default: 1000,
        validators: []
    },
    {
        key: 'runner_gid_max',
        desc: 'Maximum gid to use for runner',
        default: 1500,
        validators: []
    }
];

const default_config = [
    ...header.split('\n'),
    ...options.map(option => `
${[
        ...option.desc.split('\n'),
        option.options?('Options: ' + option.options.join(', ')):''
    ].filter(x=>x.length>0).map(x=>`# ${x}`).join('\n')}
${option.key}: ${option.default}
    `)].join('\n');

logger.info(`Loading Configuration from ${argv.config}`);
!!argv['make-config'] && logger.debug('Make configuration flag is set');

if(!!argv['make-config'] && !fss.exists_sync(argv.config)){
    logger.info('Writing default configuration...');
    try {
        fss.write_file_sync(argv.config, default_config);    
    } catch (err) {
        logger.error('Error writing default configuration:', err.message);
        process.exit(1);
    }
    

}
var config = {};
logger.debug('Reading config file');
try{
    const cfg_content = fss.read_file_sync(argv.config);
    try{
        config = yaml.load(cfg_content);
    }catch(err){
        logger.error('Error parsing configuration file:', err.message);
        process.exit(1);
    }

}catch(err){
    logger.error('Error reading configuration from disk:', err.message);
    process.exit(1);
}

logger.debug('Validating config entries');
var errored=false;
options.forEach(opt => {
    logger.debug('Checking key',opt.key);
    var cfg_val = config[opt.key];
    if(cfg_val == undefined){
        errored = true;
        logger.error(`Config key ${opt.key} does not exist on currently loaded configuration`);
        return;
    }
    opt.validators.forEach(validator => {
        var response = validator(cfg_val);
        if(response !== true){
            errored = true;
            logger.error(`Config key ${opt.key} failed validation:`, response);
            return;
        }
    });
});

if(errored) process.exit(1);

logger.info('Configuration successfully loaded');

module.exports = config;