#!/usr/bin/env ruby
# A small script to import a production gzip'ed dump
 
require "yaml"
require File.expand_path(File.dirname(__FILE__) + "/../../config/environment")
 
class DatabaseLoader
  attr_reader :db_dump_filename
  
  def initialize(filename, run_migrations=false)
    @db_dump_filename = filename.dup
    @run_migrations = run_migrations ? true : false
  end
  
  def load
    # gunzip
    # import
    redefine_views
    # run_migrations
  end
  
  def gunzip
    if needs_unziping?
      puts "* Gunzip'ing #{db_dump_filename}"
      puts %x(gunzip #{db_dump_filename})
      @db_dump_filename.gsub!(".gz", "")
    end
  end
 
  def import
    puts "* Importing db dump #{db_dump_filename} to #{database_name}"
    %x(mysql -u root #{database_name} < #{db_dump_filename})
  end
  
  def run_migrations
    if should_run_migrations?
      puts "* Running migrations"
      puts `rake db:migrate`
    end
  end
 
  def redefine_views
    puts "* Redefining views under the current database user"
    ViewRedefiner.redefine_views!
  end
 
private
  
  def should_run_migrations?
    @run_migrations == true
  end
 
  def needs_unziping?
    db_dump_filename.include?(".gz")
  end
 
  def database_name
    @database_name ||= development_config["database"]
  end
  
  def database_username
    development_config["username"]
  end
  
  def database_host
    development_config["host"]
  end
  
  def development_config
    yaml_config["development"]
  end
 
  def yaml_config
    @yaml_config ||= YAML.load(File.read("config/database.yml"))
  end
 
  def db_dump_contents(&blk)
    File.open(db_dump_filename, "r+", &blk)
  end
end
 
class ViewRedefiner
  def self.redefine_views!
    new.redefine_views
  end
 
  def redefine_views
    views.each do |view|
      redefine_view(view)
    end
  end
 
  def redefine_view(view)
    definition = get_view_definition(view)
    definition.gsub(/ALGORITHM.*DEFINER=.*SQL SECURITY DEFINER\s+/, "")
    drop_view(view)
    create_view(definition)
  end
 
  def get_view_definition(view_name)
    execute_returning_hash("SHOW CREATE TABLE `#{view_name}`").first["Create View"]
  end
 
  def drop_view(view_name)
    execute "DROP VIEW `#{view_name}"
  end
 
  # [{"collation_connection"=>"utf8_general_ci",
  #   "character_set_client"=>"utf8",
  #   "Create View"=>
  #    "CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `causes_index` AS (select `causes`.`id` AS `id`,`causes`.`name` AS `name`,`categories`.`name` AS `category_name`,`causes`.`website` AS `website`,if((`causes`.`display_on_homepage` = 1),_utf8'Yes',_utf8'No') AS `homepage_bool`,`causes`.`image_id` AS `image_id`,`causes`.`slug` AS `slug` from (`causes` left join `categories` on((`causes`.`category_id` = `categories`.`id`))))",
  #   "View"=>"causes_index"}]
  def create_view(definition)
    execute definition
  end
 
  # >> pp hash
  # [{"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"braintree_orders_index"},
  #  {"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"causes_index"},
  #  {"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"competitions_index"},
  #  {"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"pencil_orders_index"},
  #  {"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"products_index"},
  #  {"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"promo_code_index"},
  #  {"Table_type"=>"VIEW", "Tables_in_designcause_dev"=>"submissions_index"}]
  def views
    show_views.map { |x| x.to_a.last.last }
  end
 
  def show_views
    execute_returning_hash("SHOW FULL TABLES WHERE table_type = 'view'")
  end
 
  def execute_returning_hash(stmt)
    execute(stmt).all_hashes.dup
  end
 
  def execute(stmt)
    puts "* Executing sql: #{stmt}"
    ActiveRecord::Base.connection.execute(stmt)
  end
end
 
db_loader = DatabaseLoader.new(ARGV[0], ARGV[1])
db_loader.load