module SchemaToRxYaml

# File lib/restfulx/schema_to_rx_yaml.rb, line 89
def self.schema_to_rx_yaml
  # Iterates through your database, and sets up table_arr with all columns
  #  - excludes schema_info/schema_migrations/and any other tables you specify in restfulx.yml
  table_arr = ActiveRecord::Base.connection.tables - 
    %w(schema_info schema_migrations).map - 
    RxSettings.ignored.tables[0].split
    
  # Excludes columns from each table
  disregarded_columns = %w(id created_at updated_at) + RxSettings.ignored.fields[0].split
  
  # Schema variable is appended to throughout, and is the variable exported to model.yml
  schema = []
  
  # Set up empty array for has_many relationships
  @array_of_has_manies = []

  # Iterates through each table, and checks for any database field ending in _id
  table_arr.each do |table|
    column_arr = ActiveRecord::Base.connection.columns(table)
    column_arr.each do |col|
      col_name = col.name.to_s
      @array_of_has_manies << "#{col_name.gsub(/_id\b/,'')}_#{table}" if col_name[-3,3]=='_id'
    end
  end

  table_arr.each do |table|
    # Set up empty arrays for other associations
    belong_tos = []
    has_manies = []
    polymorphics = []

    # Append table name to schema
    #  - project:
    schema << "#{table.singularize}:\n" 
    column_arr = ActiveRecord::Base.connection.columns(table)

    column_arr.each do |col|
      col_name = col.name.to_s
      
      # Ignore certain columns
      columns_check = []
      disregarded_columns.each {|dc| columns_check << col_name.include?(dc) }
      
      # Sets up polymorphics array, we'll need to check for duplicates below
      polymorphics << col_name.gsub('_id','PMCHECK').gsub('_type','PMCHECK')

      # Appends each column under respective table
      schema << " - #{col_name}: #{col.type}\n" unless columns_check.include?(true)

      # Checks for certain column names
      #  - If it finds parent_id it sets up a tree_model for generation
      #  - If it finds _file_size it sets up attachment for generation
      #  - Sets up belong_tos
      if col_name == 'parent_id'
        schema << " - tree_model: [#{col_name.gsub(/_id\b/,'')}]\n" 
      elsif col_name =~ /_file_size$/
        schema << " - attachment_field: [#{col_name.gsub(/_file_size$/,'')}]\n" 
      else
        belong_tos << col_name.gsub(/_id\b/,', ') if col_name[-3,3]=='_id' && !disregarded_columns.include?(col_name)
      end
    end

    # Checks for duplicates in the polymorphics array (used for error checking)
    if polymorphics.dups.size > 0
      schema << " - polymorphic: [#{polymorphics.dups.first.gsub('PMCHECK','')}]\n" 
      @polymorphic = polymorphics.dups.first.gsub('PMCHECK','')
    end

    # Cleans up has many
    @array_of_has_manies.each do |hm|
      sanity_check = hm.gsub(/^#{table.singularize}_/,'')
      if hm =~ /^#{table.singularize}_/ && table_arr.include?(sanity_check)
        has_manies << hm.gsub(/^#{table.singularize}_/,'') + ', '
      end
    end

    # Appends belong_to's to schema
    if belong_tos.size > 0
      belong_tos = belong_tos.delete_if {|x| x == "#{@polymorphic}, " }
      break if belong_tos.size == 0   # fixing to get around nil error when you only have one polymorphic belong_to
      last_in_array_fix = belong_tos.last
      last_in_array_fix = last_in_array_fix.gsub(', ','')
      belong_tos.pop
      belong_tos << last_in_array_fix
      schema << " - belongs_to: [#{belong_tos}]\n" 
    end

    # Appends has_manies' to schema
    if has_manies.size > 0
      last_in_array_fix = has_manies.last
      last_in_array_fix = last_in_array_fix.gsub(', ','') unless last_in_array_fix.nil?
      has_manies.pop
      has_manies << last_in_array_fix
      schema << " - has_many: [#{has_manies}]\n" 
    end

    schema << "\n" 
  end

  # Writes model.yml file
  yml_file = File.join(RAILS_ROOT, "db", "model.yml")
  File.open(yml_file, "w") { |f| f << schema.to_s }
  puts "model.yml created at db/model.yml" 
end