#!/usr/bin/env ruby
# Copyright (c) 2022 Yegor Bugayenko
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the 'Software'), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

STDOUT.sync = true

require 'slop'
require 'loog'
require 'octokit'
require 'nokogiri'
require 'backtrace'
require 'fileutils'
require 'obk'
require_relative '../lib/cobench/version'

loog = Loog::REGULAR

def config(path)
  f = File.expand_path(path)
  args = []
  args += File.readlines(f).map(&:strip).reject { |a| a.empty? } if File.exist?(f)
  args
end

args = config('~/.cobench') + config('.cobench') + ARGV

opts = Slop.parse(args, strict: true, help: true) do |o|
  o.banner = "Usage (#{Cobench::VERSION}): cobench [options]"
  o.bool '-h', '--help', 'Show these instructions'
  o.bool '--version', 'Show current version'
  o.bool '--verbose', 'Print as much log messages as possible'
  o.bool '--dry', 'Make no real round trips to GitHub'
  o.bool '--reuse', 'Don\'t fetch from GitHub, reuse the existing XML file'
  o.integer '--days', 'How many days to measure', default: 7
  o.string '--to', 'Directory where to save all files to', default: './cobench'
  o.string '--token', 'GitHub authentication token'
  o.array '--coder', 'GitHub nickname of a coder to track'
  o.array '--metrics', 'Names of metrics to use (all by default)'
  o.array '--include', 'Mask of GitHub repo to include, e.g. yegor256/*'
  o.array '--exclude', 'Mask of GitHub repo to exclude'
end

if opts.help? || opts[:coder].empty?
  puts opts
  exit
end

if opts.verbose?
  loog = Loog::VERBOSE
end

if opts.version?
  loog.info(Cobench::VERSION)
  exit
end

Encoding.default_external = Encoding::UTF_8
Encoding.default_internal = Encoding::UTF_8

def div(a, b)
  return 0 if b == 0
  a / b
end

def actual(ms)
  return 0 if ms.nil?
  return ms[:actual] if ms.key?(:actual)
  ms[:total]
end

def build_xml(opts, loog)
  if opts.token?
    api = Octokit::Client.new(:access_token => opts[:token])
  else
    api = Octokit::Client.new
    loog.warn("Connecting to GitHub without a token, this may lead to errors, use --token")
  end
  api.auto_paginate = true
  api = Obk.new(api, pause: 2000)
  loog.info("Reading GitHub data for the last #{opts[:days]} days")
  titles = {}
  data = {}
  orgs = {}
  opts[:coder].each do |u|
    user = u.downcase
    loog.info("Scanning #{user}...")
    data[user] = {}
    Dir[File.join(__dir__, '../lib/cobench/metrics/*.rb')].each do |f|
      name = File::basename(f).split('.')[0]
      if !opts[:metrics].empty? && !opts[:metrics].include?(name)
        loog.info("Ignoring #{user}/#{name} due to --metrics")
        next
      end
      type = "Cobench::#{name.capitalize}"
      loog.info("Reading #{user}/#{name}...")
      require_relative f
      m = type.split('::').reduce(Module, :const_get).new(api, user, opts)
      if opts.dry?
        measures = [
          { title: 'Issues', total: Random.new.rand(100), href: 'https://github.com/' },
          { title: 'Pulls', total: Random.new.rand(100) },
          { title: 'Commits', total: Random.new.rand(100) },
          { title: 'HoC', total: Random.new.rand(100) },
          { title: 'HoC', total: Random.new.rand(100) },
          { meta: true, title: 'Orgs', list: ['objectionary', 'artipie'] },
        ]
      else
        measures = m.take(loog)
      end
      measures.reject {|ms| ms.key?(:meta)}.each do |ms|
        before = 0
        before += data[user][ms[:title]][:total] if data[user][ms[:title]] != nil
        data[user][ms[:title]] = { total: ms[:total] + before, href: ms[:href] }
        titles[ms[:title]] = ms[:title]
        loog.info("The value of #{user}/#{ms[:title]} is #{ms[:total]}")
      end
      measures.select {|ms| ms.key?(:meta)}.each do |ms|
        if ms[:title] == 'Orgs'
          orgs[user] = [] unless orgs.key?(user)
        end
        orgs[user] += ms[:list]
      end
    end
  end
  caps = {
    'HoC' => lambda { |ms| ms['Pulls'][:total] * 1024 },
  }
  data.each do |u, ms|
    ms.map do |t, h|
      next unless caps.key?(t)
      cap = caps[t].call(ms)
      if h[:total] > cap
        data[u][t][:actual] = h[:total]
        data[u][t][:total] = cap
      end
    end
    data[u] = ms
  end
  weights = {
    'HoC' => 1,
    'Pulls' => 250,
    'Issues' => 50,
    'Commits' => 5,
    'Reviews' => 150,
    'Msgs' => 5
  }
  data.each do |u, ms|
    score = ms.map do |t, h|
      raise "Unknown title '#{t}'" unless weights.key?(t)
      h[:total] * weights[t]
    end.inject(0, :+)
    data[u]['Score'] = { total: score }
  end
  averages = {
    'CpP': {
      f: lambda { |ms| div(actual(ms['Commits']), actual(ms['Pulls'])) },
      title: 'Commits per Pull Request'
    },
    'HpP': {
      f: lambda { |ms| div(actual(ms['HoC']), actual(ms['Pulls'])) },
      title: 'HoC per Pull Request'
    },
    'HpC': {
      f: lambda { |ms| div(actual(ms['HoC']), actual(ms['Commits'])) },
      title: 'HoC per Commit'
    },
    'MpRP': {
      f: lambda { |ms| div(actual(ms['Msgs']), actual(ms['Reviews']) + actual(ms['Pulls'])) },
      title: 'Messages per Review+Pulls'
    }
  }
  data.each do |u, ms|
    averages.each do |k, a|
      data[u][k] = { total: a[:f].call(ms) }
    end
  end
  builder = Nokogiri::XML::Builder.new(:encoding => 'UTF-8') do |xml|
    xml.cobench(time: Time.now, days: opts[:days]) do
      xml.titles do
        data.map { |_, ms| ms.keys }.flatten.uniq.each do |t|
          xml.title do
            xml.parent.set_attribute('subtitle', averages[t][:title]) if averages.key?(t)
            xml.text t
          end
        end
      end
      xml.weights do
        weights.each do |t, w|
          xml.w(id: t) do
            xml.text(w)
          end
        end
      end
      xml.totals do
        data.map { |_, ms| ms.keys }.flatten.uniq.each do |t|
          next if t == 'Score'
          next if averages.key?(t)
          xml.w(id: t) do
            xml.text(data.values.map { |ms| actual(ms[t]) }.inject(&:+))
          end
        end
      end
      xml.averages do
        data.map { |_, ms| ms.keys }.flatten.uniq.each do |t|
          next if t == 'Score'
          xml.w(id: t) do
            vals = data.values.map { |ms| actual(ms[t]) }.select { |v| v > 0 }
            xml.text(div(vals.inject(&:+), vals.count))
          end
        end
      end
      xml.coders do
        data.each do |u, ms|
          xml.coder(id: u) do
            xml.parent.set_attribute('details', api.user(u).name) unless opts[:dry]
            if orgs.key?(u)
              xml.orgs do
                orgs[u].uniq.each do |o|
                  xml.org o
                end
              end
            end
            xml.metrics do
              ms.each do |k, v|
                xml.m(id: k) do
                  xml.parent.set_attribute('actual', v[:actual]) unless v[:actual].nil?
                  xml.parent.set_attribute('href', v[:href]) unless v[:href].nil?
                  xml.text v[:total]
                end
              end
            end
          end
        end
      end
    end
  end
  xml = builder.to_xml
  loog.debug(xml)
  xml
end
begin
  home = File.absolute_path(opts[:to])
  loog.debug("All files generated will be saved to #{home}")
  if File.exist?(home)
    loog.debug("Directory #{home} exists")
  else
    FileUtils.mkdir_p(home)
    loog.debug("Directory #{home} created")
  end
  index = File.join(home, 'index.xml')
  if opts[:reuse]
    xml = File.read(index)
  else
    xml = build_xml(opts, loog)
    File.write(index, xml)
    loog.debug("XML saved to #{index} (#{File.size(index)} bytes)")
  end
  xslt = Nokogiri::XSLT(File.read(File.join(__dir__, '../assets/index.xsl')))
  html = xslt.transform(Nokogiri::XML(xml), 'version' => "'#{Cobench::VERSION}'")
  loog.debug(html)
  front = File.join(home, 'index.html')
  File.write(front, html.to_html(indent: 0).gsub("\n", ''))
  loog.debug("HTML saved to #{front} (#{File.size(front)} bytes)")
rescue StandardError => e
  loog.error(Backtrace.new(e))
  exit -1
end