#!/usr/bin/env ruby

# frozen_string_literal: true

require 'json'
require 'pathname'
require 'time'
require 'yaml'
require 'zlib'

CONFIG_PATH = 'config/solidus_compare.yml'

@config = {}
@cmd_options = {}
ARGV.each do |arg|
  case arg
  when '-h', '--help'
    puts <<~HELP
      Solidus Compare: a tool to detect changes between 2 repositories

      Options:
        -h or --help          : show this help
        -s or --summary       : generate an XML summary of the files changed (used in CI)
        -u or --update-ignore : update the config file setting the current hashes to ignore
    HELP
    exit 0
  when '-s', '--summary'
    @cmd_options[:summary] = true
  when '-u', '--update-ignore'
    @cmd_options[:update] = true
  end
end

# ---------------------------------------------------------------------------- #

def generate_comparison(report)
  report.each do |data|
    conf = @config['ignore'].find { |cfg| cfg['path'] == data['path'] }
    diffs = conf ? (conf['diffs'] || []) : []
    data['diffs'].each do |result|
      info = diffs.find { |diff| diff['file'] == result['file'] } || {}
      if info['skip']
        result['skip'] = true
        result.delete 'hash'
        next
      elsif info['hash'] == result['hash']
        next
      end

      puts result['diff']
    end
  end
  update_ignore(report) if @cmd_options[:update]
end

def generate_summary(report) # rubocop:disable Metrics/MethodLength
  summary = {}
  report.each do |data|
    path = data['path']
    conf = @config['ignore'].find { |cfg| cfg['path'] == path }
    diffs = conf ? (conf['diffs'] || []) : []
    data['diffs'].each do |result|
      info = diffs.find { |diff| diff['file'] == result['file'] } || {}
      next if info['skip'] || info['hash'] == result['hash']

      (summary[path] ||= {})[result['hash']] = result['file']
    end
  end

  count = 0
  testcases = summary.map do |file_path, value|
    value.map do |hash, file|
      count += 1
      full_path = Pathname.new(file_path).join(file).to_s
      "<testcase name=\"#{file}\" file=\"#{full_path}\" time=\"0\"><failure>hash: #{hash}\nfile: #{file}</failure></testcase>"
    end
  end.join("\n")

  output = <<~SUMMARY
    <?xml version="1.0" encoding="UTF-8"?>
    <testsuite name="solidus_compare" tests="#{count}" skipped="0" failures="#{count}" errors="#{count}" time="1" timestamp="#{Time.now.iso8601}">
    #{testcases}
    </testsuite>
  SUMMARY
  puts output

  exit 1 if count.positive?
end

def load_config
  @config = YAML.load_file(CONFIG_PATH) if File.exist?(CONFIG_PATH)
  @config ||= {}
  @config['ignore'] ||= []
  @config['project_paths'] ||= []
  @config['source_repo'] ||= 'https://github.com/solidusio/solidus.git'
  @config['source_name'] ||= 'solidus'
  @config['source_branch'] ||= 'master'
  @config['source_base_path'] ||= 'frontend/'
end

def solidus_compare
  report = @config['project_paths'].map do |path|
    remote_source = "remotes/#{@config['source_name']}/#{@config['source_branch']}"
    remote_path = "#{@config['source_base_path']}#{path}"
    result = `git diff "#{remote_source}" -- "#{remote_path}" "#{path}"`
    puts("error with git diff #{path}") & exit if $?.exitstatus != 0

    result.gsub!(/index\s[\w\d]+\.\.[\w\d]+\s[\w\d]+\n/, '')
    diffs = result.split(/diff --git /)[1..-1]
    next unless diffs

    {
      'path' => path,
      'diffs' => diffs.map do |diff|
        next if diff.include? 'similarity index 100%'

        {
          'hash' => Zlib.crc32(diff),
          'file' => diff.match(%r{a/([^\s]+)})&.send(:[], 1),
          'diff' => 'diff --git ' + diff
        }
      end.compact
    }

    # end
  end.compact

  @cmd_options[:summary] ? generate_summary(report) : generate_comparison(report)
end

def update_ignore(report)
  report.each do |data|
    data['diffs'].each do |result|
      result.delete('diff')
    end
  end.compact
  @config['ignore'] = report
  File.open(CONFIG_PATH, 'w') { |f| f.puts(@config.to_yaml) }
end

def update_source
  if `git remote`.split("\n").none? @config['source_name']
    `git remote add -f #{@config['source_name']} #{@config['source_repo']}`
    puts('error with git remote add') & exit if $?.exitstatus != 0
  end

  `git remote update > /dev/null 2>&1`
  puts('error with git remote update') & exit if $?.exitstatus != 0
end

# ---------------------------------------------------------------------------- #

load_config
update_source
solidus_compare