const fs = require('fs')


let paths = []
let options = []

for(arg of process.argv.slice(3)){
    if(arg.startsWith('--')){
        options.push(arg)
    }
    else if(arg.startsWith('-')){
        for(let option of arg.slice(1)){
            options.push('-' + option);
        }
    }
    else{
        paths.push(arg)
    }
}

if(paths.length == 0){
    paths = ['.'];
}


try{
    
    listFiles(paths[0], options)
}
catch(e){
    switch(e.code){
        case "ENOENT":
            console.error(`path "${paths[0]}" does not exist`);
            break;
        default:
            console.error(`ls: ${e.code}`)
    }
}




function listFiles(path, options){
    const files = ['.', '..'].concat(fs.readdirSync(paths[0]))
    const nonHiddenFiles = files.filter(file => file[0] != '.')
    colorList = JSON.parse(process.env.ls_color)
    if(options.includes('-l')){
        console.log(`total ${options.includes('-a') ? files.length : nonHiddenFiles.length}`)
        for(let file of options.includes('-a') ? files : nonHiddenFiles){
            
            stats = fs.lstatSync(`${path}/${file}`);
            mode = stats.mode
            result = ""
            let color = []
            let defaultColor = "\x1b[0m"
            let fileType = "-"
            if(stats.isFile()){
                fileType = "-";
                if(stats.mode & 00100){ //owner can execute
                    color = colorList.ex ? `\x1b[${colorList.ex[0]}m\x1b[${colorList.ex[1]}m` : "\x1b[0m"
                } 
            }
            else if (stats.isDirectory()) {
                fileType = "d"; 
                color = colorList.di ? `\x1b[${colorList.di[0]}m\x1b[${colorList.di[1]}m` : "\x1b[0m"
            }
            else if (stats.isSymbolicLink()){
                fileType = "l"
                color = colorList.ln ? `\x1b[${colorList.ln[0]}m\x1b[${colorList.ln[1]}m` : "\x1b[0m"
            }
            result += fileType;
            permissions = "xwr"
            for(let i=8;i>=0;i--){
                result += parseInt(Math.pow(2,i).toString(2)) & mode ?  permissions[i%3] : '-'
            }
            if(01000 & mode){ // check sticky bit
                color = "\x1b[40m\x1b[92m\x1b[7m"
            } 
            let date = new Date(stats.mtimeMs*1000).toDateString().split(' ');
            result += ` ${usernameFromUID(stats.uid)}\t${groupnameFromGID(stats.gid)}\t${stats.size}\t${date[2]} ${date[1]}. ${options.includes('--color') ? color : ""}${file}${defaultColor}`
            console.log(result)
        }
    }
    else{
        result = ""
        const defaultColor = "\x1b[0m";
        if(options.includes('--color')){
            for(let file of options.includes('-a') ? files : nonHiddenFiles){
                stats = fs.lstatSync(`${path}/${file}`);
                let color = defaultColor
                if(stats.isDirectory()){
                    color = colorList.di ? `\x1b[${colorList.di[1]}m\x1b[${colorList.di[0]}m` : defaultColor
                }
                else if (stats.isSymbolicLink()){
                    color = colorList.ln ? `\x1b[${colorList.ln[1]}m\x1b[${colorList.ln[0]}m` : defaultColor
                }
                if(01000 & stats.mode){ // check sticky bit
                    color = "\x1b[40m\x1b[92m\x1b[7m"
                } 
                result += color + file + defaultColor + "  ";
            }
            console.log(result)
        }else{
            console.log(options.includes('-a') ? files.join('  ') : nonHiddenFiles.join('  '))
        }
    }
}   

function usernameFromUID(uid){
    const passwd = fs.readFileSync("/etc/passwd", {encoding: 'utf-8'}).split('\n');
    for(let line of passwd){
        let lineSplited = line.split(':')
        if(lineSplited[2] == uid){
            return lineSplited[0];
        }
    }
    return uid
}

function groupnameFromGID(uid){
    const passwd = fs.readFileSync("/etc/passwd", {encoding: 'utf-8'}).split('\n');
    for(let line of passwd){
        let lineSplited = line.split(':')
        if(lineSplited[3] == uid){
            return lineSplited[0];
        }
    }
    return uid
}