require "dbi"
require "readline"

class ReadlineControl
  
  def initialize
    @keywords = []
    set_prompt
    Readline.completion_proc = proc {|str| complete(str) }
  end

  def add_keywords(arr)
    @keywords += arr
  end

  def complete(str)
    @keywords.grep(/^#{Regexp.escape(str)}/i)
  end

  def set_prompt(prompt="> ")
    @prompt = prompt
  end

  def readline
    Readline.readline(@prompt, true)
  end

end

class ConnectionInfo
  attr_reader :user, :passwd, :driver_url, :driver_name, :driver_parameter

  def initialize(driver_url, user=nil, passwd=nil)
    @user       = user
    @passwd     = passwd
    @driver_url = driver_url
    driver_url =~ /dbi:([^:]*)(:(.*))?/
    @driver_name = $1
    @driver_parameter = $3
  end

  def to_a
    return @driver_url, @user, @passwd
  end

  def to_s
    "#@driver_url #@user #@passwd"
  end

  # %u = username
  # %d = driver name
  # %D = driver URL
  # %p = driver_specific_parameter
  
  def subst_prompt(str)
    str = str.gsub("%u", @user || "")
    str = str.gsub("%d", @driver_name)
    str = str.gsub("%D", @driver_url)
    str = str.gsub("%p", @driver_parameter)
  end

end
 

PROMPT_NOCONN = ENV['SQLSH_PROMPT_NOCONN'] || "dbi # " 
PROMPT  = ENV['SQLSH_PROMPT']  || "%u@%D # "
PROMPT2 = ENV['SQLSH_PROMPT2'] || "%u@%D \ " 

SQL_KEYWORDS = %w(
  INSERT DELETE UPDATE SELECT FROM WHERE IN LIKE SET VALUES INTO
  CREATE TABLE DROP 
  COMMIT ROLLBACK
  CHAR VARCHAR VARCHAR2 INT INTEGER NUMBER FLOAT REAL LONG CLOB BLOB DECIMAL 
  DBCLOB DBBLOB
)





if ARGV.size == 0 
  $conn = nil
  $dbconn = nil
elsif ARGV.size >= 1 and ARGV.size <= 3 
  $conn = ConnectionInfo.new(*ARGV)
  $dbconn = nil

  begin
    $dbconn = DBI.connect(*$conn.to_a)
  rescue DBI::Error, DBI::Warning
    puts "ERROR: Couldn't connect to #{$conn.to_s}"
    p $!
    $conn = nil
    $dbconn = nil
  end
  puts "Successfully connected with #{$conn.to_s}"
else
  puts
  puts "USAGE: #{$0} [driver_url [user [password] ]]"
  puts
  exit 1
end


def prompt(cont=false)
  if $conn.nil?
    PROMPT_NOCONN
  else
    if cont
      $conn.subst_prompt(PROMPT2)
    else
      $conn.subst_prompt(PROMPT)
    end
  end
end



rd = ReadlineControl.new
rd.add_keywords SQL_KEYWORDS
rd.set_prompt(prompt)


loop {
  line = rd.readline
  line.chomp!
  next if line.empty?

  begin 

    if line =~ /^\\/ then
      #if line =~ /^\\list tables/i then
        #stmt = Conn.createStatement.tables
      #elsif line =~ /^\\list views/i then
      #  stmt = Conn.createStatement.tables("%", "%", "VIEW")

      if line =~ /^\\q/i then
        break 
      elsif line =~ /^\\disconnect/i then
        if $dbconn.nil?
          puts "Cannot disconnect! No connection!"
        else
          $dbconn.disconnect
          $dbconn = $conn = nil
          puts "Disconnected"
          rd.set_prompt(prompt)
        end
        
      elsif line =~ /^\\connect ([^ ].*)/i then
        if $dbconn.nil?
          begin
            $conn = ConnectionInfo.new(* $1.split(/ /) )
            $dbconn = DBI.connect(*$conn.to_a)
            rd.set_prompt(prompt)
          rescue DBI::Error, DBI::Warning
            puts "ERROR: Couldn't connect to #{$conn.to_s}"
            p $!
            $conn = nil
            $dbconn = nil
          end
          puts "Successfully connected with #{$conn.to_s}"

        else
          puts "Cannot connect! Disconnect first connection!"
        end

      else
        puts
        puts "Unknown command!"
        puts
        next
      end
    else
      # multi-line
      if line[-1].chr == "\\" then
        line.chop!
        rd.set_prompt(prompt(true))
        loop {
          ln = rd.readline
          line.chomp!
          next if line.empty?
           
          if ln[-1].chr == "\\" then
            line += ln.chop
          else
            line += ln
            break
          end
        }
      end

      rd.set_prompt(prompt)

      if $dbconn.nil? then
        puts "Cannot execute <#{line}>, no connection"
        next
      else

        stmt = $dbconn.prepare(line)
        head = stmt.column_names
        next if head.empty? 
        rows = stmt.fetch_all
        DBI::Utils::TableFormatter.ascii(head, rows)

      end
    end

  rescue DBI::Error, DBI::Warning => err
    puts
    puts err.message
    puts
  end


}

$dbconn.disconnect unless $dbconn.nil?