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const prompts = require('prompts');
const { findRepos } = require('jest-changed-files');
const simpleGit = require('simple-git/promise');

class JestWatchBranchPlugin {
getUsageInfo() {
return {
key: 'b',
prompt: 'test changes since a given branch',
};
}

async run(globalConfig, updateConfigAndRun) {
const branches = await this._getBranches(globalConfig.rootDir);
const { branch } = await prompts({
type: 'select',
name: 'branch',
message: 'Which branch do you want to base off of?',
choices: branches,
});

updateConfigAndRun({ mode: 'watch', changedSince: branch });

process.stdin.setRawMode(true);
process.stdin.resume();

return true;

}

async _getBranches(rootDir) {
// findRepos return a set of git repos and a set of hg repos.
// It doesn't really make sense to use this plugin across different
// repositories, so we assume there's a single repository
// for rootDir by just getting the first one
const { git: roots } = await findRepos([rootDir]);

const [root] = Array.from(roots);

if (!root) {
  throw new Error('Unable to find git root');
}

const repo = simpleGit(root);

const { branches } = await repo.branch();

return Object.values(branches)
  .map(branch => ({
    ...branch,
    name: branch.name.replace(/^remotes\//, ''),
  }))
  .map(({ current, name }) => ({
    value: name,
    title: current ? `${name} (current branch)` : name,
  }));

}
}

module.exports = JestWatchBranchPlugin;