module Flydata
module Sync

class MysqlTableDef
  TYPE_MAP_M2F = {
    'bigint' => 'int8',
    'binary' => 'binary',
    'blob' => 'varbinary',
    'bool' => 'int1',
    'boolean' => 'int1',
    'char' => 'varchar',
    'date' => 'date',
    'datetime' => 'datetime',
    'dec' => 'numeric',
    'decimal' => 'numeric',
    'double' => 'float8',
    'double precision' => 'float8',
    'fixed' => 'numeric',
    'float' => 'float4',
    'int' => 'int4',
    'longblob' => 'varbinary',
    'longtext' => 'text',
    'mediumblob' => 'varbinary',
    'mediumint' => 'int3',
    'mediumtext' => 'text',
    'numeric' => 'numeric',
    'smallint' => 'int2',
    'text' => 'text',
    'time' => 'time',
    'timestamp' => 'datetime',
    'tinyblob' => 'varbinary',
    'tinyint' => 'int1',
    'tinytext' => 'text',
    'varbinary' => 'varbinary',
    'varchar' => 'varchar',
  }

  def self.create(io)
    params = _create(io)
    params ? self.new(*params) : nil
  end

  def initialize(table_def, table_name, columns, default_charset, comment)
    @table_def = table_def
    @table_name = table_name
    @columns = columns
    @default_charset = default_charset
    @comment = comment
  end

  def self._create(io)
    
    table_def = ''
    table_name = nil
    columns = []
    default_charset = nil
    comment = nil

    position = :before_create_table
    io.each_line do |line|
      if line =~ /CREATE TABLE `(.*?)`/
        position = :in_create_table
        table_name = $1
      end

      next unless position == :in_create_table

      table_def += line.chomp

      if line =~ /^\s*`(.*?)`\s+([a-z()0-9,\s]+)/ # column def
        name = $1
        type = $2.strip
        type = type[0..-2] if type.end_with?(',')
        TYPE_MAP_M2F.each do |mysql_type, flydata_type|
          type.gsub!(/\b#{mysql_type}\b/, flydata_type)
        end
        column = {name: name, type: type}
        column[:auto_increment] = true if line =~ /AUTO_INCREMENT/
        column[:not_null] = true if line =~ /NOT NULL/
        if /DEFAULT\s+((?:[^'\s]+\b)|(?:'(?:\\'|[^'])*'))/.match(line)
          val = $1
          val = val.slice(1..-1) if val.start_with?("'")
          val = val.slice(0..-2) if val.end_with?("'")
          column[:default] = val == "NULL" ? nil : val
        end
        if /COMMENT\s+'(((?:\\'|[^'])*))'/.match(line)
          column[:comment] = $1
        end
        columns << column
      end

      if line =~ /PRIMARY KEY/
        primary_keys = line.scan(/`(.*?)`/).collect{|item| item[0]}
        primary_keys.each do |primary_key|
          column = columns.detect {|column|
            column[:name] === primary_key
          }
          raise "PK #{primary_key} must exist in the definition " if column.nil?
          column[:primary_key] = true
        end
      end

      if line =~ /DEFAULT CHARSET\s*=\s*([^\s]+)/
        default_charset = $1
      end

      if line =~ /ENGINE=.*/  # TODO Need better parsing.
        position = :after_create_table
        break
      end
    end
    position == :after_create_table ? [table_def, table_name, columns, default_charset, comment] : nil
  end
  attr_reader :columns, :table_name

  def to_flydata_tabledef
    tabledef = { table_name: @table_name,
                 columns: @columns,
               }
    tabledef[:default_charset] = @default_charset if @default_charset
    tabledef[:comment] = @comment if @comment

    tabledef
  end
end

end
end