import gql from 'graphql-tag'
import Joi from 'joi'
import { InvalidResponse } from '../index.js'
import { metric } from '../text-formatters.js'
import { nonNegativeInteger } from '../validators.js'
import { GithubAuthV4Service } from './github-auth-service.js'
import { transformErrors, documentation } from './github-helpers.js'

const schema = Joi.object({
  data: Joi.object({
    repository: Joi.object({
      object: Joi.object({
        history: Joi.object({
          totalCount: nonNegativeInteger,
        }).required(),
      }),
    }).required(),
  }).required(),
}).required()

export default class GitHubCommitActivity extends GithubAuthV4Service {
  static category = 'activity'
  static route = {
    base: 'github/commit-activity',
    pattern: ':interval(y|m|4w|w)/:user/:repo/:branch*',
  }

  static examples = [
    {
      title: 'GitHub commit activity',
      // Override the pattern to omit the deprecated interval "4w".
      pattern: ':interval(y|m|w)/:user/:repo',
      namedParams: { interval: 'm', user: 'eslint', repo: 'eslint' },
      staticPreview: this.render({ interval: 'm', commitCount: 457 }),
      keywords: ['commits'],
      documentation,
    },
    {
      title: 'GitHub commit activity (branch)',
      // Override the pattern to omit the deprecated interval "4w".
      pattern: ':interval(y|m|w)/:user/:repo/:branch*',
      namedParams: {
        interval: 'm',
        user: 'badges',
        repo: 'squint',
        branch: 'main',
      },
      staticPreview: this.render({ interval: 'm', commitCount: 5 }),
      keywords: ['commits'],
      documentation,
    },
  ]

  static defaultBadgeData = { label: 'commit activity', color: 'blue' }

  static render({ interval, commitCount }) {
    const intervalLabel = {
      y: '/year',
      m: '/month',
      '4w': '/four weeks',
      w: '/week',
    }[interval]

    return {
      message: `${metric(commitCount)}${intervalLabel}`,
    }
  }

  async fetch({ interval, user, repo, branch = 'HEAD' }) {
    const since = this.constructor.getIntervalQueryStartDate({ interval })
    return this._requestGraphql({
      query: gql`
        query (
          $user: String!
          $repo: String!
          $branch: String!
          $since: GitTimestamp!
        ) {
          repository(owner: $user, name: $repo) {
            object(expression: $branch) {
              ... on Commit {
                history(since: $since) {
                  totalCount
                }
              }
            }
          }
        }
      `,
      variables: {
        user,
        repo,
        branch,
        since,
      },
      schema,
      transformErrors,
    })
  }

  static transform({ data }) {
    const {
      repository: { object: repo },
    } = data

    if (!repo) {
      throw new InvalidResponse({ prettyMessage: 'invalid branch' })
    }

    return repo.history.totalCount
  }

  static getIntervalQueryStartDate({ interval }) {
    const now = new Date()

    if (interval === 'y') {
      now.setUTCFullYear(now.getUTCFullYear() - 1)
    } else if (interval === 'm' || interval === '4w') {
      now.setUTCDate(now.getUTCDate() - 30)
    } else {
      now.setUTCDate(now.getUTCDate() - 7)
    }

    return now.toISOString()
  }

  async handle({ interval, user, repo, branch }) {
    const json = await this.fetch({ interval, user, repo, branch })
    const commitCount = this.constructor.transform(json)
    return this.constructor.render({ interval, commitCount })
  }
}