// Ben's amazing dotfiles installer!
// it would be super cool if it did stuff like notice a new hostname
// and respond by backing up the current dotfiles in a new host file
// TODO: 
//  - Util scripts to add dotfiles
//      - this could even be extended to auto profile the host & move
//      stuff accordingly
//  - .zshrc, .profile etc should create a new file and append
//  "source .zshrc.laptop" to the current one, in order to not mess
//  up specific environments
//
// FEATURES:
//  - Backup current dotfiles to dotfiles.bak/
//  - Create symlinks between dotfiles and the actual dotfiles

import fs from 'fs';
import { readdir } from 'fs/promises';
import opsys from 'os';
import path from 'path';
import { parseArgs } from 'node:util';
import subProcess from 'child_process';

const HOME = opsys.homedir() + '/';

const VERSION_MAJOR = 1;
const VERSION_MINOR = 0;
const VERSION_PATCH = 1;

console.log('Ben\'s amazing dotfiles installer!');
console.log(`Version v${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH}`);

const {
    values: { 
        host, os 
    }
} = parseArgs({
    options: {
        host: {
            type: 'string',
            short: 'h',
        },
        os: {
            type: 'string',
            short: 'o',
        },
    },
});

const panic = (error) => {
    console.error('Error: ' + error);
    console.error('usage: bootstrap -h <host> -o <os>');
    process.exit(0);
}

if (!host) {
    panic('Incorrect usage');
}

if (os) {
    // check we have the host
    const dir = fs.readdirSync('.', { withFileTypes: true }).filter(d => d.isDirectory() && !d.name.startsWith('.')).map(d => d.name);
    if (!dir.includes(host)) {
        panic(`Host ${host} does not exist`);
    }

    // install the packages that the dotfiles need to function properly
    const targetInstallScript = os + '.os';
    const installScripts = fs.readdirSync('.').filter(f => f.endsWith('.os'));
    if (!installScripts.includes(targetInstallScript)) {
        panic(`OS ${os} does not exist`);
    }

    console.log('Installing dependencies...');
    subProcess.spawnSync('./' + targetInstallScript, [], {
        stdio: 'inherit', 
    });

    console.log('Successfully installed OS deps...');
}

// we want to create a symlink between common/ & {host}/ to ~/
// for every file stored in this repo, so we need
// to create a .bak/ of the origionals as this might 
// well cause some issues...

const deepReadDir = async (dirPath) => await Promise.all(
    (await readdir(dirPath, {withFileTypes: true})).map(async (dirent) => {
        const currentPath = path.join(dirPath, dirent.name)
        return dirent.isDirectory() ? await deepReadDir(currentPath) : currentPath;
    }),
)

const parentDir = 'common/';
const childDir = host + '/';
const basePaths = (await deepReadDir(parentDir)).flat(999);
const childPaths = (await deepReadDir(childDir)).flat(999);

// start by making the backup
const backupDir = HOME + 'dotfiles.bak/'; // TODO: make this a cmd option
console.log(`Backing up current dotfiles to ${backupDir}`);

// delete current backupDir first, we might want to warn the user of this Y/n
if (fs.existsSync(backupDir))
    fs.rmSync(backupDir, { recursive: true });
if (!fs.existsSync(backupDir))
    fs.mkdirSync(backupDir);

const anonBasePaths = basePaths.map(e => e.split('/').slice(1).join('/'));
const anonChildPaths = childPaths.map(e => e.split('/').slice(1).join('/'));
const allAnonPaths = Array.from(new Set(anonBasePaths.concat(anonChildPaths)));

for (const path of allAnonPaths) {
    const copyTarget = HOME + path;
    if (!fs.existsSync(copyTarget)) {
        console.log(`Not backing up ${copyTarget}... it does not exist...`);
        continue;
    }
    
    const backupTarget = backupDir + path;
    const backupTargetDir = backupTarget.substring(0, backupTarget.lastIndexOf('/') + 1);
    
    console.log(`Moving ${copyTarget} to ${backupTarget}`);
    if (!fs.existsSync(backupTargetDir)) {
        console.log(`${backupTargetDir} does not exist... creating`);
        fs.mkdirSync(backupTargetDir, { recursive: true });
    }
    fs.copyFileSync(copyTarget, backupTarget);
}

// we prioritise targetDir over parentDir
// we first need to make a list that includes both the
// base and childPaths without the base if child exists
let symLinks = basePaths.filter(e => {
    return !anonChildPaths.includes(e.split('/').slice(1).join('/'))
});
symLinks = symLinks.concat(childPaths);

for (const symLink of symLinks) {
    const targetSymLink = HOME + (symLink.split('/').slice(1).join('/')) 
    const sourceSymLink = process.cwd() + '/' + symLink;
    console.log(`Creating symlink between ${sourceSymLink} to ${targetSymLink}`);

    if (!fs.existsSync(targetSymLink.substring(0, targetSymLink.lastIndexOf('/')))) {
        fs.mkdirSync(targetSymLink.substring(0, targetSymLink.lastIndexOf('/')), { recursive: true });
    }
    
    if (fs.existsSync(targetSymLink)) {
        fs.rmSync(targetSymLink);    
    }

    fs.symlinkSync(sourceSymLink, targetSymLink);
}

console.log('Done!');