# frozen_string_literal: true

require 'octokit'
require 'date'

class ReviewReport
  def initialize(token:, repo:, branch:, duration:)
    @token = token
    @repo = repo
    @branch = branch
    @duration_in_days = duration
  end

  def percentile(array, percentile)
    sorted_array = array.sort
    k = (percentile * (sorted_array.length - 1)).floor
    l = k + 1
    q1 = sorted_array[k]
    q2 = sorted_array[l]
    q1 + (q2 - q1) * (percentile * (sorted_array.length - 1) - k)
  end

  def report
    client = Octokit::Client.new(access_token: @token)
    client.auto_paginate = true

    # Fetch pull requests created after the target date
    pull_requests = client.list_issues(@repo, state: 'closed', since: DateTime.now - @duration_in_days)

    # Group pull requests by week
    pull_requests_by_week = pull_requests.group_by { |pr| pr[:closed_at].strftime('%Y-%W') }

    weeks = @duration_in_days / 7

    # Iterate over months within the days duration limit
    pull_requests_by_week.keys.sort[-weeks..].each do |week|
      total_time_seconds = 0
      total_count = 0
      total_count_calc = 0
      total_reviews = 0
      reviews_with_comments = 0
      change_requested_reviews = 0

      # Iterate over pull requests in the week
      pull_requests_by_week[week].each do |issue|
        pull_request = client.pull_request(@repo, issue.number)
        last_commit_sha = pull_request[:head][:sha]
        last_commit = client.commit(@repo, last_commit_sha)

        reviews = []
        review_page = 1
        loop do
          response = client.pull_request_reviews(@repo, pull_request[:number], per_page: 100,
                                                                               page: review_page)
          break if response.empty?

          reviews.concat(response)
          review_page += 1
        end

        total_reviews += reviews.size

        next unless reviews.any?

        last_review = reviews.max_by { |review| review[:submitted_at] }
        time_taken_seconds = (last_review[:submitted_at] - last_commit[:commit][:author][:date]).abs

        if time_taken_seconds / 3600.0 < 8 && time_taken_seconds / 3600.0 > 0.3
          total_time_seconds += time_taken_seconds
          total_count_calc += 1
        end
        total_count += 1
        # Count reviews with comments
        reviews_with_comments += reviews.count do |review|
          comments = client.pull_request_review_comments(@repo, pull_request[:number], review[:id])
          comments.any?
        end

        # Count reviews with "change_requested" state
        change_requested_reviews += reviews.count { |review| review[:state] == 'CHANGES_REQUESTED' }
      end

      if total_count.positive?
        average_time_hours = total_time_seconds / total_count_calc / 3600.0 # Convert seconds to hours
        puts "Calendar week #{week}: Average time taken for #{total_count} pull requests is #{average_time_hours.round(2)} hours."
        puts "  Total reviews: #{total_reviews}"
        puts "  Reviews with comments: #{reviews_with_comments}"
        puts "  Change requested reviews: #{change_requested_reviews}"

        # ENV['BQ_CREDENTIALS'] = `cat /Users/serghei.moret/.config/gcloud/application_default_credentials.json`

        if ENV['BQ_CREDENTIALS']
          require 'google/cloud/bigquery'
          require 'json'
          creds = JSON.parse(ENV['BQ_CREDENTIALS'])
          bigquery = Google::Cloud::Bigquery.new(
            project_id: 'hellofresh-android',
            credentials: creds
          )
          dataset = bigquery.dataset 'github_data'

          query = <<~SQL
            MERGE INTO pr_reviews AS target
            USING (SELECT '#{week}' AS calendar_week, '#{@repo}' AS platform) AS source
            ON target.calendar_week = source.calendar_week AND target.platform = source.platform
            WHEN MATCHED THEN
              UPDATE SET
                target.change_requested_reviews = #{change_requested_reviews},
                target.reviews_with_comments = #{reviews_with_comments},
                target.total_reviews = #{total_reviews},
                target.average_review_time_hours = #{average_time_hours.round(2)},
                target.total_prs = #{total_count},
                target.platform = '#{@repo}'
            WHEN NOT MATCHED THEN
              INSERT (calendar_week, total_prs, average_review_time_hours, total_reviews, reviews_with_comments, change_requested_reviews, platform)
              VALUES ('#{week}', #{total_count}, #{average_time_hours.round(2)}, #{total_reviews}, #{reviews_with_comments}, #{change_requested_reviews}, '#{@repo}');
          SQL

          dataset.query(query)
        end
      else
        puts "#{week}: No pull requests with reviews."
      end
    end
  end
end