#
#       ActiveFacts Oracle SQL Schema Generator
#
# Copyright (c) 2009-2016 Clifford Heath. Read the LICENSE file.
#
# Reserved words gathered from:
# https://docs.oracle.com/cd/B28359_01/appdev.111/b31231/appb.htm
#
require 'digest/sha1'
require 'activefacts/metamodel'
require 'activefacts/compositions'
require 'activefacts/generator/sql'

module ActiveFacts
  module Generators
    # Options are comma or space separated:
    # * underscore 
    class SQL
      class Oracle < SQL
        def self.options
          super.merge({
            # no: [String, "no new options defined here"]
          })
        end

        def initialize composition, options = {}
          super(composition, {'tables' => 'shout', 'columns' => 'shout'}.merge(options))
        end

        def table_name_max
          30
        end

        def data_type_context
          OracleDataTypeContext.new
        end

        def auto_assign_modifier
          ' GENERATED BY DEFAULT ON NULL AS IDENTITY'
        end

        def generate_schema
          ''
        end

        def normalise_type(type_name, length, value_constraint, options)
          type = MM::DataType.normalise(type_name)
          case type
          when MM::DataType::TYPE_Integer
            if aa = options[:auto_assign]
              'LONGINTEGER'
            else
              super
            end
          when MM::DataType::TYPE_Money;    'MONEY'
          when MM::DataType::TYPE_DateTime; 'DATETIME'
          when MM::DataType::TYPE_Timestamp;'DATETIME'
          when MM::DataType::TYPE_Binary;
            if type_name =~ /^(guid|uuid)$/i && (!length || length == 16)
              if ![nil, ''].include?(options[:auto_assign])
                options[:default] = " DEFAULT SYS_GUID()"
                options.delete(:auto_assign)
              end
              return ['RAW', 32]
            end
            ['LOB', length]
          else
            super
          end
        end

        # Reserved words cannot be used anywhere without quoting.
        # Keywords have existing definitions, so should not be used without quoting.
        # Both lists here are added to the supertype's lists
        def reserved_words
          @oracle_reserved_words ||= %w{
            ACCESS ARRAYLEN AUDIT CLUSTER COMMENT COMPRESS EXCLUSIVE
            IDENTIFIED INDEX INITIAL LOCK LONG MAXEXTENTS MINUS
            MODE MODIFY NOAUDIT NOCOMPRESS NOTFOUND NOWAIT OFFLINE
            ONLINE PCTFREE RAW RENAME RESOURCE ROWID ROWLABEL ROWNUM
            SHARE SQLBUF SUCCESSFUL SYNONYM SYSDATE UID VALIDATE
            VARCHAR2
          }
          @oracle_plsql_reserved_words ||= %w{
            ABORT ACCEPT ACCESS ARRAYLEN ASSERT ASSIGN BASE_TABLE
            BINARY_INTEGER BODY CHAR_BASE CLUSTER CLUSTERS COLAUTH
            COMPRESS CONSTANT CRASH CURRVAL DATABASE DATA_BASE DBA
            DEBUGOFF DEBUGON DEFINITION DELAY DELTA DIGITS DISPOSE
            ELSIF ENTRY EXCEPTION_INIT FORM GENERIC IDENTIFIED INDEX
            INDEXES LIMITED MINUS MLSLABEL MODE NEXTVAL NOCOMPRESS
            NUMBER_BASE PACKAGE PCTFREE POSITIVE PRAGMA PRIVATE
            RAISE RECORD REMR RENAME RESOURCE REVERSE ROWID ROWLABEL
            ROWNUM ROWTYPE RUN SEPARATE SQLERRM STDDEV SUBTYPE
            TABAUTH TABLES TASK TERMINATE USE VARCHAR2 VARIANCE
            VIEWS XOR
          }
          super + @oracle_reserved_words
        end

        def key_words
          # These keywords should not be used for columns or tables:
          @oracle_key_words ||= %w{
            ANALYZE ARCHIVE ARCHIVELOG BACKUP BECOME BLOCK BODY
            CACHE CANCEL CHANGE CHECKPOINT COMPILE CONTENTS CONTROLFILE
            DATABASE DATAFILE DBA DISABLE DISMOUNT DUMP ENABLE
            EVENTS EXCEPTIONS EXPLAIN EXTENT EXTERNALLY FLUSH FORCE
            FREELIST FREELISTS INITRANS LAYER LISTS LOGFILE MANAGE
            MANUAL MAXDATAFILES MAXINSTANCES MAXLOGFILES MAXLOGHISTORY
            MAXLOGMEMBERS MAXTRANS MINEXTENTS MOUNT NOARCHIVELOG
            NOCACHE NOCYCLE NOMAXVALUE NOMINVALUE NOORDER NORESETLOGS
            NORMAL NOSORT OPTIMAL OWN PACKAGE PARALLEL PCTINCREASE
            PCTUSED PLAN PRIVATE PROFILE QUOTA RECOVER RESETLOGS
            RESTRICTED REUSE ROLES SCN SEGMENT SHARED SNAPSHOT SORT
            STATEMENT_ID STATISTICS STOP STORAGE SWITCH TABLES
            TABLESPACE THREAD TRACING TRIGGERS UNLIMITED USE
          }
          super + @oracle_key_words
        end

        def go s = ''
          "#{s};\n\n"
        end

        def open_escape
          '"'
        end

        def close_escape
          '"'
        end

        def index_kind(index)
          ''
        end

        class OracleDataTypeContext < SQLDataTypeContext
          def integer_ranges
            [
              ['SHORTINTEGER', -2**15, 2**15-1],  # The standard says -10^5..10^5 (less than 16 bits)
              ['INTEGER', -2**31, 2**31-1],   # The standard says -10^10..10^10 (more than 32 bits!)
              ['LONGINTEGER', -2**63, 2**63-1],    # The standard says -10^19..10^19 (less than 64 bits)
            ]
          end

          def boolean_type
            'BOOLEAN'
          end

          def valid_from_type
            'TIMESTAMP'
          end

          # There is no performance benefit in using fixed-length CHAR fields,
          # and an added burden of trimming the implicitly added white-space
          def default_char_type
            (@unicode ? 'N' : '') +
            'VARCHAR'
          end

          def default_varchar_type
            (@unicode ? 'N' : '') +
            'VARCHAR'
          end

          def date_time_type
            'TIMESTAMP'
          end
        end
      end

    end
    publish_generator SQL::Oracle
  end
end