#This class handels the SQLite3-specific behaviour for columns.
class KnjDB_sqlite3::Columns
  attr_reader :db
  
  #Constructor. This should not be called manually.
  def initialize(args)
    @args = args
  end
  
  #Returns SQL for a knjdb-compatible hash.
  def data_sql(data)
    raise "No type given." if !data["type"]
    type = data["type"].to_s
    
    if type == "enum"
      type = "varchar"
      data.delete("maxlength")
    end
    
    data["maxlength"] = 255 if type == "varchar" and !data.key?("maxlength")
    data["maxlength"] = 11 if type == "int" and !data.key?("maxlength") and !data["autoincr"] and !data["primarykey"]
    type = "integer" if @args[:db].int_types.index(type) and (data["autoincr"] or data["primarykey"])
    
    sql = "`#{data["name"]}` #{type}"
    sql << "(#{data["maxlength"]})" if data["maxlength"] and !data["autoincr"]
    sql << " PRIMARY KEY" if data["primarykey"]
    sql << " AUTOINCREMENT" if data["autoincr"]
    sql << " NOT NULL" if !data["null"] and data.key?("null")
    
    if data.key?("default_func")
      sql << " DEFAULT #{data["default_func"]}"
    elsif data.key?("default") and data["default"] != false
      sql << " DEFAULT '#{@args[:db].escape(data["default"])}'"
    end
    
    return sql
  end
end

#This class handels all the SQLite3-columns.
class KnjDB_sqlite3::Columns::Column
  attr_reader :args
  
  #Constructor. This should not be called manually.
  def initialize(args)
    @args = args
    @db = @args[:db]
  end
  
  #Returns the name of the column.
  def name
    return @args[:data][:name]
  end
  
  #Returns the columns table-object.
  def table
    return @db.tables[@args[:table_name]]
  end
  
  #Returns the data of the column as a hash in knjdb-format.
  def data
    return {
      "type" => self.type,
      "name" => self.name,
      "null" => self.null?,
      "maxlength" => self.maxlength,
      "default" => self.default,
      "primarykey" => self.primarykey?,
      "autoincr" => self.autoincr?
    }
  end
  
  #Returns the type of the column.
  def type
    if !@type
      if match = @args[:data][:type].match(/^([A-z]+)$/)
        @maxlength = false
        type = match[0].to_sym
      elsif match = @args[:data][:type].match(/^decimal\((\d+),(\d+)\)$/)
        @maxlength = "#{match[1]},#{match[2]}"
        type = :decimal
      elsif match = @args[:data][:type].match(/^enum\((.+)\)$/)
        @maxlength = match[1]
        type = :enum
      elsif match = @args[:data][:type].match(/^(.+)\((\d+)\)$/)
        @maxlength = match[2]
        type = match[1].to_sym
      elsif @args[:data].key?(:type) and @args[:data][:type].to_s == ""
        #A type can actually be empty in SQLite... Wtf?
        return @args[:data][:type]
      end
      
      if type == :integer
        @type = :int
      else
        @type = type
      end
      
      raise "Still not type? (#{@args[:data]})" if @type.to_s.strip.length <= 0
    end
    
    return @type
  end
  
  #Returns true if the column allows null. Otherwise false.
  def null?
    return false if @args[:data][:notnull].to_i == 1
    return true
  end
  
  #Returns the maxlength of the column.
  def maxlength
    self.type if !@maxlength
    return @maxlength if @maxlength
    return false
  end
  
  #Returns the default value of the column.
  def default
    def_val = @args[:data][:dflt_value]
    if def_val.to_s.slice(0..0) == "'"
      def_val = def_val.to_s.slice(0)
    end
    
    if def_val.to_s.slice(-1..-1) == "'"
      def_val = def_val.to_s.slice(0, def_val.length - 1)
    end
    
    return false if @args[:data][:dflt_value].to_s.length == 0
    return def_val
  end
  
  #Returns true if the column is the primary key.
  def primarykey?
    return false if @args[:data][:pk].to_i == 0
    return true
  end
  
  #Returns true if the column is auto-increasing.
  def autoincr?
    return true if @args[:data][:pk].to_i == 1 and @args[:data][:type].to_s == "integer"
    return false
  end
  
  #Drops the column from the table.
  def drop
    self.table.copy("drops" => self.name)
  end
  
  #Changes data on the column. Like the name, type, maxlength or whatever.
  def change(data)
    newdata = data.clone
    
    newdata["name"] = self.name if !newdata.key?("name")
    newdata["type"] = self.type if !newdata.key?("type")
    newdata["maxlength"] = self.maxlength if !newdata.key?("maxlength") and self.maxlength
    newdata["null"] = self.null? if !newdata.key?("null")
    newdata["default"] = self.default if !newdata.key?("default")
    newdata["primarykey"] = self.primarykey? if !newdata.key?("primarykey")
    
    @type = nil
    @maxlength = nil
    
    new_table = self.table.copy(
      "alter_columns" => {
        self.name.to_s => newdata
      }
    )
  end
end