const fs = require('fs');
const path = require('path');

const branchName = getCurrentBranchName();
if (branchName) {
    const msgPath = `.git/COMMIT_EDITMSG`;
    const msg = fs.readFileSync(msgPath, 'utf-8');

    const referenceTag = `refs #${branchName.match(/^\d+/)}`;
    console.log('referenceTag: ', referenceTag);
    console.log(msg);

    if (!msg.includes(referenceTag)) {
        const splitedMsg = msg.split(':');

        if (splitedMsg.length > 1) {
            const finalMsg = splitedMsg[0] + ': ' + referenceTag + splitedMsg.slice(1).join(':');
            console.log('finalMsg: ', finalMsg);
            fs.writeFileSync(msgPath, finalMsg);
        }
    }
}

function getCurrentBranchName(p = process.cwd()) {
    if (!fs.existsSync(p)) return false;

    const gitHeadPath = path.join(p, '.git', 'HEAD');

    if (!fs.existsSync(gitHeadPath))
        return getCurrentBranchName(path.resolve(p, '..'));

    const headContent = fs.readFileSync(gitHeadPath, 'utf-8');
    return headContent.trim().split('/')[2];
}