#!/usr/bin/env ruby

require 'github_api'
require 'json'
require 'httparty'
require 'colorize'
require_relative 'github_changelog_generator/parser'


class ChangelogGenerator

  attr_accessor :options, :all_tags, :github

  def initialize()

    @options = Parser.parse_options

    github_token

    if @github_token.nil?
      @github = Github.new
    else
      @github = Github.new oauth_token: @github_token
    end

    @all_tags = self.get_all_tags
    @pull_requests = self.get_all_closed_pull_requests
    @issues = self.get_all_issues

    @tag_times_hash = {}
  end

  def print_json(json)
    puts JSON.pretty_generate(json)
  end

  def exec_command(cmd)
    exec_cmd = "cd #{$project_path} && #{cmd}"
    %x[#{exec_cmd}]
  end


  def get_all_closed_pull_requests
    response = @github.pull_requests.list @options[:user], @options[:project], :state => 'closed'

    pull_requests = []
    response.each_page do |page|
      pull_requests.concat(page)
    end

    if @options[:verbose]
      puts "Receive all pull requests: #{pull_requests.count}"
    end

    pull_requests
  end

  def compund_changelog
    if @options[:verbose]
      puts 'Generating changelog:'
    end

    log = "# Changelog\n\n"

    if @options[:last]
      log += self.generate_log_between_tags(self.all_tags[0], self.all_tags[1])
    elsif @options[:tag1] && @options[:tag2]

      tag1 = @options[:tag1]
      tag2 = @options[:tag2]
      tags_strings = []
      self.all_tags.each { |x| tags_strings.push(x['name']) }

      if tags_strings.include?(tag1)
        if tags_strings.include?(tag2)
          hash = Hash[tags_strings.map.with_index.to_a]
          index1 = hash[tag1]
          index2 = hash[tag2]
          log += self.generate_log_between_tags(self.all_tags[index1], self.all_tags[index2])
        else
          puts "Can't find tag #{tag2} -> exit"
          exit
        end
      else
        puts "Can't find tag #{tag1} -> exit"
        exit
      end
    else
      log += self.generate_log_for_all_tags
    end

    log += "\n\n\\* *This changelog was generated by [github_changelog_generator](https://github.com/skywinder/Github-Changelog-Generator)*"

    output_filename = "#{@options[:output]}"
    File.open(output_filename, 'w') { |file| file.write(log) }

    puts "Done! Generated log placed in #{output_filename}"

  end

  def generate_log_for_all_tags
    log = ''
    @all_tags.each {|tag| self.get_time_of_tag(tag)}


    if @options[:verbose]
      puts "Sorting tags.."
    end

    @all_tags.sort_by! {|x| self.get_time_of_tag(x)}.reverse!

    if @options[:verbose]
      puts "Generating log.."
    end

    for index in 1 ... self.all_tags.size
      log += self.generate_log_between_tags(self.all_tags[index], self.all_tags[index-1])
    end

    log += self.generate_log_before_tag(self.all_tags.last)

    log
  end

  def is_megred(number)
    @github.pull_requests.merged? @options[:user], @options[:project], number
  end

  def get_all_tags

    url = "https://api.github.com/repos/#{@options[:user]}/#{@options[:project]}/tags"

    if @options[:verbose]

      puts "Receive tags for repo #{url}"
    end

    response = @github.repos.tags @options[:user], @options[:project]

    tags = []
    response.each_page do |page|
      tags.concat(page)
    end

    if @options[:verbose]
      puts "Found #{tags.count} tags"
    end

    tags
  end

  def github_token
    if @options[:token]
      return @github_token ||= @options[:token]
    end

    env_var = ENV.fetch 'CHANGELOG_GITHUB_TOKEN', nil

    unless env_var
      puts "Warning: No token provided (-t option) and variable $CHANGELOG_GITHUB_TOKEN was not found.".yellow
      puts "This script can make only 50 requests to GitHub API per hour without token!".yellow
    end

    @github_token ||= env_var

  end


  def generate_log_between_tags(older_tag, newer_tag)
    older_tag_time = self.get_time_of_tag(older_tag)
    newer_tag_time = self.get_time_of_tag(newer_tag)

    # if we mix up tags order - lits fix it!
    # if older_tag_time < newer_tag_time
    #   older_tag, newer_tag = newer_tag, older_tag
    #   older_tag_time, newer_tag_time = newer_tag_time, older_tag_time
    #   puts "Swap tags!"
    # end

    newer_tag_name = newer_tag['name']

    pull_requests = Array.new(@pull_requests)

    pull_requests.delete_if { |req|
      if req[:merged_at]
        t = Time.parse(req[:merged_at]).utc
        tag_is_older_of_older = t > older_tag_time
        tag_is_newer_than_new = t <= newer_tag_time

        tag_not_in_range = (tag_is_older_of_older) && (tag_is_newer_than_new)
        !tag_not_in_range
      else
        true
      end

    }

    issues = Array.new(@issues)

    issues.delete_if { |issue|
      if issue[:closed_at]
        t = Time.parse(issue[:closed_at]).utc
        tag_is_later_since = t > older_tag_time
        tag_is_before_till = t <= newer_tag_time

        in_range = (tag_is_later_since) && (tag_is_before_till)
        !in_range
      else
        true
      end

    }

    self.create_log(pull_requests, issues, newer_tag_name, newer_tag_time)

  end

  def generate_log_before_tag(tag)
    tag_time = self.get_time_of_tag(tag)
    tag_name = tag['name']

    pull_requests = Array.new(@pull_requests)

    pull_requests.delete_if { |req|
      if req[:merged_at]
        t = Time.parse(req[:merged_at]).utc
        t > tag_time
      else
        true
      end

    }

    issues = Array.new(@issues)

    issues.delete_if { |issue|
      if issue[:closed_at]
        t = Time.parse(issue[:closed_at]).utc
        t > tag_time
      else
        true
      end
    }

    self.create_log(pull_requests, issues, tag_name, tag_time)

  end

  def create_log(pull_requests, issues, tag_name, tag_time)

    # Generate tag name and link
    trimmed_tag = tag_name.tr('v', '')
    log = "## [#{trimmed_tag}] (https://github.com/#{@options[:user]}/#{@options[:project]}/tree/#{tag_name})\n"

    #Generate date string:
    time_string = tag_time.strftime @options[:format]
    log += "#### #{time_string}\n"

    if @options[:pulls]
      # Generate pull requests:
      if pull_requests
        pull_requests.each { |dict|
          merge = "#{@options[:merge_prefix]}#{dict[:title]} [\\##{dict[:number]}](#{dict.html_url})\n\n"
          log += "- #{merge}"
        }
      end
    end

    if @options[:issues]
      # Generate issues:
      if issues
        issues.sort! { |x, y|
          if x.labels.any? && y.labels.any?
            x.labels[0].name <=> y.labels[0].name
          else
            if x.labels.any?
              1
            else
              if y.labels.any?
                -1
              else
                0
              end
            end
          end
        }.reverse!
      end
      issues.each { |dict|
        is_bug = false
        is_enhancement = false
        dict.labels.each { |label|
          if label.name == 'bug'
            is_bug = true
          end
          if label.name == 'enhancement'
            is_enhancement = true
          end
        }

        intro = 'Closed issue'
        if is_bug
          intro = 'Fixed bug'
        end

        if is_enhancement
          intro = 'Implemented enhancement'
        end

        merge = "*#{intro}:* #{dict[:title]} [\\##{dict[:number]}](#{dict.html_url})\n\n"
        log += "- #{merge}"
      }
    end
    log
  end

  def get_time_of_tag(prev_tag)

    if @tag_times_hash[prev_tag['name']]
      return @tag_times_hash[prev_tag['name']]
    end

    if @options[:verbose]
      puts "Getting time for tag #{prev_tag['name']}"
    end

    github_git_data_commits_get = @github.git_data.commits.get @options[:user], @options[:project], prev_tag['commit']['sha']
    time_string = github_git_data_commits_get['committer']['date']
    Time.parse(time_string)
    @tag_times_hash[prev_tag['name']] = Time.parse(time_string)
  end

  def get_all_issues
    response = @github.issues.list user: @options[:user], repo: @options[:project], state: 'closed', filter: 'all', labels: nil


    issues = []
    response.each_page do |page|
      issues.concat(page)
    end

    # remove pull request from issues:
    issues.select! { |x|
      x.pull_request == nil
    }

    if @options[:verbose]
      puts "Receive all closed issues: #{issues.count}"
    end

    filtered_issues = issues.select { |issue|
      #compare is there any labels from @options[:labels] array
      (issue.labels.map { |label| label.name } & @options[:labels]).any?
    }

    if @options[:add_issues_wo_labels]
      issues_wo_labels = issues.select {
        # add issues without any labels
          |issue| !issue.labels.map { |label| label.name }.any?
      }
      filtered_issues.concat(issues_wo_labels)
    end

    if @options[:verbose]
      puts "Filter issues with labels #{@options[:labels]}#{@options[:add_issues_wo_labels]? ' and w/o labels' : ''}: #{filtered_issues.count} issues"
    end

    filtered_issues

  end

end

if __FILE__ == $0
  changelog_generator = ChangelogGenerator.new
  changelog_generator.compund_changelog
end