const keygen = require('ssh-keygen-lite');
const fs = require('fs')
const simpleGit = require("simple-git")
const path = require("path")

/**
 * 
 * @param {String} a 
 * @returns 
 */
function resolvePath(a) {
    a = a.replace("\\",path.sep)
    return path.resolve(a)
}

require("dotenv").config()

const GIT_URI = process.env.GIT_URI
const GIT_BRANCH = process.env.GIT_BRANCH || "main"

const shouldGenerateKeys = process.env.GENERATE_KEYS || GIT_URI.startsWith("ssh://") || false

const PROJECT_DIR = resolvePath(__dirname + "\\project")

const KEY_DIR = resolvePath(__dirname + "\\keys")

const KEY_LOCATION = resolvePath(KEY_DIR + "\\deploy.pem")
const KEY_LOCATION_PUBLIC = resolvePath(KEY_LOCATION+".pub")
const KNOWN_HOSTS_FILE = resolvePath(__dirname + "\\known_hosts")

const KEY_FORMAT = "PEM"
const KEY_COMMENT = "nodejs-deploy"

const GIT_SSH_COMMAND = `ssh -o UserKnownHostsFile="${KNOWN_HOSTS_FILE}" -o StrictHostKeyChecking=no -i "${KEY_LOCATION}"`
//console.log(GIT_SSH_COMMAND)

async function readKeys() {
    const FILE_ENC = "UTF-8"
    const privateKey = fs.readFileSync(KEY_LOCATION,FILE_ENC)
    const publicKey = fs.readFileSync(KEY_LOCATION_PUBLIC,FILE_ENC)

    const keys = {
        private: privateKey,
        public: publicKey,
    }
    return keys;
}

async function tryGenerateKeys() {
    if (!fs.existsSync(KEY_DIR)) fs.mkdirSync(KEY_DIR)
    const exists = fs.existsSync(KEY_LOCATION);
    if (exists) {
        console.log("no need to generate key, already exists")
        return;
    }
    if (!shouldGenerateKeys) {
        console.log("shouldGenerateKeys is false, skipping key generation")
        return;
    }
    console.log("Generating keys...")
    const aPromise = new Promise(function(resolve, reject) {
        keygen({
                location: KEY_LOCATION,
                type: 'rsa',
                read: true,
                force: false,
                destroy: false,
                comment: KEY_COMMENT,
                //password: 'keypassword',
                size: '4096',
                format: KEY_FORMAT,
            },
            // If you omit this callback function, a Promise will be returned instead!
            function onDoneCallback(err, out) {
                // The error could be related to ssh-keygen binary or file system errors.
                if (err) {
                    console.error(err)
                    reject(err);
                    return;
                }
                resolve(true);   
            },
        );
    })
    return await aPromise;
}

async function gitMain() {

    /**
    * @type {import('simple-git').SimpleGit}
    */
    const cloneGit = simpleGit(__dirname)
    cloneGit.env('GIT_SSH_COMMAND', GIT_SSH_COMMAND)

    if (!fs.existsSync(PROJECT_DIR)) {
        await cloneGit.clone(GIT_URI, PROJECT_DIR)
    }
     /**
    * @type {import('simple-git').SimpleGit}
    */
    const git = simpleGit(PROJECT_DIR)
    git.env('GIT_SSH_COMMAND', GIT_SSH_COMMAND)
    const fetchResult = await git.fetch()
    const localBranches = await git.branchLocal()
    
    const statusResult = await git.status()
    //console.log(statusResult)
    if (statusResult.current != GIT_BRANCH && !localBranches.all.includes(GIT_BRANCH)) {
        await git.checkoutBranch(GIT_BRANCH, `origin/${GIT_BRANCH}`)
    } else {
        await git.checkout(GIT_BRANCH)
    }
    //console.log(statusResult)
    const behind = statusResult.behind
    if (behind > 0 ) {
        console.log(`${behind} change behind, pulling...`)
        await git.pull()
    }
    console.log(`Local version is up-to date with branch "${GIT_BRANCH}"`)
    if (statusResult.files.length > 0) {
        console.log("Locally changed Files: ",statusResult.files)
    }
}

const { execSync, spawn } = require('child_process')

async function ProjectCmd(cmd) {
    //console.log(`executing "${cmd}"`)
    const processPromise = new Promise(function(resolve, reject) {
        const process = spawn(cmd, { stdio: 'inherit', cwd: PROJECT_DIR, shell:true });

        process.on('close', (code) => {
            //console.log(`command "${cmd}" exited with code ${code}`);
            resolve();
        }); 
    })
    return await processPromise;
    
}

async function RunProject(commands = ["npm i","npm start"]) {
    for (let index = 0; index < commands.length; index++) {
        await ProjectCmd(commands[index])
    }
}

async function main() {
    const didGenerate = await tryGenerateKeys()
    if (didGenerate) {
        console.log("Keys have been placed in the keys directory.")
        return
    }
    await gitMain()

    let customCommands = process.env.COMMANDS
    //console.log(customCommands)
    if (customCommands) {
        try {
            customCommands = JSON.parse(customCommands)
        } catch {
            console.error("couln't parse commands from .env")
            customCommands = undefined;
        }
    }
    
    console.log("custom start commands",customCommands)
    RunProject(customCommands)
}

main()