class OCI8::Cursor

def self.select_number_as
  case @@bind_unknown_number
  when OCI8::BindType::Fixnum
    return Fixnum
  when OCI8::BindType::Integer
    return Integer
  when OCI8::BindType::Float
    return Float
  end
end

def self.select_number_as=(val)
  if val == Fixnum
    @@bind_unknown_number = OCI8::BindType::Fixnum
  elsif val == Integer
    @@bind_unknown_number = OCI8::BindType::Integer
  elsif val == Float
    @@bind_unknown_number = OCI8::BindType::Float
  else
    raise ArgumentError, "must be Fixnum, Integer or Float"
  end
end

def [](key)
  handle = @bind_handles[key]
  handle && handle.send(:get_data)
end

def []=(key, val)
  handle = @bind_handles[key]
  return nil if handle.nil?
  if val.is_a? Array
    if @actual_array_size > 0 && val.length != @actual_array_size
      raise RuntimeError, "all binding arrays hould be the same size"
    end
    if @actual_array_size == 0 && val.length <= @max_array_size
      @actual_array_size = val.length
    end
  end
  handle.send(:set_data, val)
  val
end

def bind_param(key, param, type = nil, length = nil)
  case param
  when Hash
  when Class
    param = {:value => nil,   :type => param, :length => length}
  else
    param = {:value => param, :type => type,  :length => length}
  end
  bindobj = make_bind_object(param)
  __bind(key, bindobj)
  if old = @bind_handles[key]
    old.send(:free)
  end
  @bind_handles[key] = bindobj
  self
end

def bind_param_array(key, var_array, type = nil, max_item_length = nil)
  raise "please call max_array_size= first." if @max_array_size.nil?
  raise "expect array as input param for bind_param_array." if !var_array.nil? && !(var_array.is_a? Array) 
  raise "the size of var_array should not be greater than max_array_size." if !var_array.nil? && var_array.size > @max_array_size
  if var_array.nil? 
    raise "all binding arrays should be the same size." unless @actual_array_size.nil? || @actual_array_size == 0
    @actual_array_size = 0
  else
    raise "all binding arrays should be the same size." unless @actual_array_size.nil? || var_array.size == @actual_array_size
    @actual_array_size = var_array.size if @actual_array_size.nil?
  end
  
  param = {:value => var_array, :type => type, :length => max_item_length, :max_array_size => @max_array_size}
  first_non_nil_elem = var_array.nil? ? nil : var_array.find{|x| x!= nil}
  
  if type.nil?
    if first_non_nil_elem.nil?
      raise "bind type is not given."
    else
      type = first_non_nil_elem.class
    end
  end
  
  bindclass = OCI8::BindType::Mapping[type]
  if bindclass.nil? and type.is_a? Class
    bindclass = OCI8::BindType::Mapping[type.to_s]
    OCI8::BindType::Mapping[type] = bindclass if bindclass
  end
  raise "unsupported dataType: #{type}" if bindclass.nil?
  bindobj = bindclass.create(@con, var_array, param, @max_array_size)
  __bind(key, bindobj)
  #
  if old = @bind_handles[key]
    old.send(:free)
  end
  @bind_handles[key] = bindobj
  self
end

def bind_params(*bindvars)
  bindvars.each_with_index do |val, i|
    if val.is_a? Array
      bind_param(i + 1, val[0], val[1], val[2])
    else
      bind_param(i + 1, val)
    end
  end
end

def close
  free()
  @names = nil
  @column_metadata = nil
end

def column_metadata
  @column_metadata
end

def define(pos, type, length = nil)
  bindobj = make_bind_object({:type => type, :length => length}, @fetch_array_size || 1)
  __define(pos, bindobj)
  if old = @define_handles[pos - 1]
    old.send(:free)
  end
  @define_handles[pos - 1] = bindobj
  self
end

def define_columns
  # http://docs.oracle.com/cd/E11882_01/appdev.112/e10646/ociaahan.htm#sthref5494
  num_cols = attr_get_ub4(18) # OCI_ATTR_PARAM_COUNT(18)
  @column_metadata = 1.upto(num_cols).collect do |i|
    __paramGet(i)
  end
  if @define_handles.size == 0
    use_array_fetch = @@use_array_fetch
    @column_metadata.each do |md|
      case md.data_type
      when :clob, :blob, :bfile
        # Rows prefetching doesn't work for CLOB, BLOB and BFILE.
        # Use array fetching to get more than one row in a network round trip.
        use_array_fetch = true
      end
    end
    @fetch_array_size = @prefetch_rows if use_array_fetch
  end
  @column_metadata.each_with_index do |md, i|
    define_one_column(i + 1, md) unless @define_handles[i]
  end
  num_cols
end

def define_one_column(pos, param)
  bindobj = make_bind_object(param, @fetch_array_size || 1)
  __define(pos, bindobj)
  @define_handles[pos - 1] = bindobj
end

def exec(*bindvars)
  bind_params(*bindvars)
  case type
  when :select_stmt
    __execute(0)
    define_columns() if @column_metadata.size == 0
    @rowbuf_size = 0
    @rowbuf_index = 0
    @column_metadata.size
  else
    __execute(1)
    row_count
  end
end

def exec_array
  raise "please call max_array_size= first." if @max_array_size.nil?
  if !@actual_array_size.nil? && @actual_array_size > 0
    __execute(@actual_array_size)
  else
    raise "please set non-nil values to array binding parameters"
  end
  case type
  when :update_stmt, :delete_stmt, :insert_stmt
    row_count
  else
    true
  end
end

def fetch
  if block_given?
    while row = fetch_one_row_as_array
      yield row
    end
    self
  else
    fetch_one_row_as_array
  end
end

def fetch_hash
  if block_given?
    while row = fetch_one_row_as_hash()
      yield row
    end
  else
    fetch_one_row_as_hash
  end
end

def fetch_one_row_as_array
  if fetch_row_internal
    ret = @define_handles.collect do |handle|
      handle.send(:get_data, @rowbuf_index)
    end
    @rowbuf_index += 1
    ret
  else
    nil
  end
end

def fetch_one_row_as_hash
  if fetch_row_internal
    ret = {}
    get_col_names.each_with_index do |name, idx|
      ret[name] = @define_handles[idx].send(:get_data, @rowbuf_index)
    end
    @rowbuf_index += 1
    ret
  else
    nil
  end
end

def fetch_row_internal
  if @rowbuf_size && @rowbuf_size == @rowbuf_index
    @rowbuf_size = __fetch(@con, @fetch_array_size || 1)
    @rowbuf_index = 0
  end
  @rowbuf_size
end

def free_bind_handles
  @bind_handles.each_value do |val|
    val.send(:free)
  end
  @bind_handles.clear
end

def get_col_names
  @names ||= @column_metadata.collect { |md| md.name }
end

def initialize(conn, sql = nil)
  @bind_handles = {}
  @define_handles = []
  @column_metadata = []
  @names = nil
  @con = conn
  @max_array_size = nil
  @fetch_array_size = nil
  @rowbuf_size = 0
  @rowbuf_index = 0
  __initialize(conn, sql) # Initialize the internal C structure.
  self.prefetch_rows = conn.instance_variable_get(:@prefetch_rows)
end

def keys
  @bind_handles.keys
end

def make_bind_object(param, fetch_array_size = nil)
  case param
  when Hash
    key = param[:type]
    val = param[:value]
    max_array_size = param[:max_array_size]
    if key.nil?
      if val.nil?
        raise "bind type is not given."
      elsif val.is_a? OCI8::Object::Base
        key = :named_type
        param = @con.get_tdo_by_class(val.class)
      else
        key = val.class
      end
    elsif key.class == Class && key < OCI8::Object::Base
      param = @con.get_tdo_by_class(key)
      key = :named_type
    elsif key == :named_type
      param = @con.get_tdo_by_typename(param[:length])
    end
  when OCI8::Metadata::Base
    key = param.data_type
    case key
    when :named_type
      if param.type_name == 'XMLTYPE'
        key = :xmltype
      else
        param = @con.get_tdo_by_metadata(param.type_metadata)
      end
    end
  else
    raise "unknown param #{param.intern}"
  end
  bindclass = OCI8::BindType::Mapping[key]
  if bindclass.nil? and key.is_a? Class
    bindclass = OCI8::BindType::Mapping[key.to_s]
    OCI8::BindType::Mapping[key] = bindclass if bindclass
  end
  raise "unsupported datatype: #{key}" if bindclass.nil?
  bindclass.create(@con, val, param, fetch_array_size || max_array_size)
end

def max_array_size=(size)
  raise "expect positive number for max_array_size." if size.nil? && size <=0
  free_bind_handles()  if !@max_array_size.nil?
  @max_array_size = size
  @actual_array_size = nil
end

def prefetch_rows=(rows)
  attr_set_ub4(11, rows) # OCI_ATTR_PREFETCH_ROWS(11)
  @prefetch_rows = rows
end

def row_count
  # https://docs.oracle.com/database/121/LNOCI/ociaahan.htm#sthref5774
  attr_get_ub8(457) # OCI_ATTR_UB8_ROW_COUNT(457)
end

def row_count
  # http://docs.oracle.com/cd/E11882_01/appdev.112/e10646/ociaahan.htm#sthref5498
  attr_get_ub4(9) # OCI_ATTR_ROW_COUNT(9)
end

def statement
  # The magic number 144 is OCI_ATTR_STATEMENT.
  # See http://docs.oracle.com/cd/E11882_01/appdev.112/e10646/ociaahan.htm#sthref5503
  attr_get_string(144)
end

def type
  # http://docs.oracle.com/cd/E11882_01/appdev.112/e10646/ociaahan.htm#sthref5506
  stmt_type = attr_get_ub2(24) # OCI_ATTR_STMT_TYPE(24)
  case stmt_type
  when 1 # OCI_STMT_SELECT
    :select_stmt
  when 2 # OCI_STMT_UPDATE
    :update_stmt
  when 3 # OCI_STMT_DELETE
    :delete_stmt
  when 4 # OCI_STMT_INSERT
    :insert_stmt
  when 5 # OCI_STMT_CREATE
    :create_stmt
  when 6 # OCI_STMT_DROP
    :drop_stmt
  when 7 # OCI_STMT_ALTER
    :alter_stmt
  when 8 # OCI_STMT_BEGIN
    :begin_stmt
  when 9 # OCI_STMT_DECLARE
    :declare_stmt
  else
    stmt_type
  end
end