// Description:
//   Script that listens for issues with the label 'bounty-awaiting-approval'
//   and notifies the collaborators on Slack.
//
// Dependencies:
//   github: "^13.1.0"
//   hashset: "0.0.6"
//   probot-config: "^0.1.0"
//
// Author:
//   Max Tyrrell (ImFeelingDucky/mac/yung_mac)

const getConfig = require('probot-config')
const HashSet = require('hashset')

const defaultConfig = require('../lib/config')
const slackHelper = require('../lib/slack')

const botName = 'bounty-awaiting-approval-slack-ping'

module.exports = (robot) => {
  registerForNewBounties(robot)
}

function registerForNewBounties (robot) {
  robot.on('issues.labeled', async context => {
    // Make sure we don't listen to our own messages
    if (context.isBot) return null

    await notifyCollaborators(context, robot)
  })
}

async function notifyCollaborators (context, robot) {
  const { github, payload } = context
  const repoInfo = { owner: payload.repository.owner.login, repo: payload.repository.name }
  const config = await getConfig(context, 'github-bot.yml', defaultConfig(robot, '.github/github-bot.yml'))
  const bountyProjectBoardConfig = config ? config['bounty-project-board'] : null
  const gitHubTeamConfig = config ? config['github-team'] : null

  if (!bountyProjectBoardConfig) {
    robot.log.debug(`${botName} - Bounty project board not configured in repo ${repoInfo.owner}/${repoInfo.repo}, ignoring`)
    return
  }

  if (!gitHubTeamConfig) {
    robot.log.debug(`${botName} - GitHub team not configured in repo ${repoInfo.owner}/${repoInfo.repo}, ignoring`)
    return
  }

  const watchedLabelName = bountyProjectBoardConfig['awaiting-approval-label-name']
  if (payload.label.name !== watchedLabelName) {
    robot.log.debug(`${botName} - '${payload.label.name}' doesn't match watched '${watchedLabelName}' label. Ignoring`)
    return null
  }

  robot.log(`${botName} - issue #${payload.issue.number} on ${repoInfo.owner}/${repoInfo.repo} was labeled as a bounty awaiting approval. Pinging slack...`)

  const slackCollaborators = await getSlackCollaborators(repoInfo, github, robot, gitHubTeamConfig)

  // Mention the project board owner as well, if configured
  const bountyProjectBoardOwner = bountyProjectBoardConfig['owner']
  if (bountyProjectBoardOwner) {
    const slackUserMention = robot.gitHubIdMapper.getSlackMentionFromGitHubId(bountyProjectBoardOwner)
    if (slackUserMention) {
      slackCollaborators.push(slackUserMention)
    }
  }

  // Send message to Slack
  slackHelper.sendMessage(
    robot,
    config.slack.notification.room,
    `New bounty awaiting approval: ${payload.issue.html_url}
/cc ${slackCollaborators.values().join(', ')}`
  )
}

function randomInt (low, high) {
  return Math.floor(Math.random() * (high - low) + low)
}

// Get the Slack IDs of the collaborators of this repo.
async function getSlackCollaborators (repoInfo, github, robot, gitHubTeamConfig) {
  const teamSlug = gitHubTeamConfig['slug']
  if (!teamSlug) {
    robot.log.debug(`${botName} - GitHub team slug not configured in repo ${repoInfo.owner}/${repoInfo.repo}, ignoring`)
    return
  }

  // Grab a list of collaborators to this repo, as an array of GitHub login usernames
  const teams = await github.paginate(github.orgs.getTeams({ org: repoInfo.owner }), res => res.data)
  const team = teams.find(t => t.slug === teamSlug)
  if (!team) {
    robot.log.debug(`${botName} - GitHub team with slug ${teamSlug} was not found. Ignoring`)
    return
  }

  const teamMembers = await github.paginate(github.orgs.getTeamMembers({id: team.id, per_page: 100}), res => res.data)

  // Create an array of Slack usernames from GitHub usernames
  const gitHubUsers = teamMembers.map(u => u.login)
  const slackUsers = new HashSet()
  for (const gitHubUser of gitHubUsers) {
    const id = await robot.gitHubIdMapper.getSlackMentionFromGitHubId(gitHubUser)
    if (id) {
      slackUsers.add(id)
    }
  }

  // Select 2 random Slack team members
  const randomTeamMemberLimit = 2
  const selectedSlackUsers = new HashSet()

  while (selectedSlackUsers.size() < randomTeamMemberLimit || selectedSlackUsers.size() < slackUsers.size()) {
    const slackUser = slackUsers[randomInt(0, slackUsers.size())]
    selectedSlackUsers.add(slackUser)
  }

  return selectedSlackUsers
}