require 'pg'

class Time
  def to_ms
    (self.to_f * 1000.0).to_i
  end
end

$newrevid = nil

def dbConnect(host, user, password, dbname)
  puts "connecting to database: #{dbname}\n"
  PGconn.open :host => host, :user => user, :password => password, :dbname => dbname
end

def getTableFields(conn, tableName)
  descbuf = "SELECT a.attnum, a.attname, t.typname, a.attlen FROM pg_class c, pg_attribute a, pg_type t WHERE c.relname = '"
  descbuf += tableName
  descbuf += "' and a.attnum > 0 and a.attrelid = c.oid and a.atttypid = t.oid "
  descbuf += "ORDER BY attnum "

  res = conn.exec(descbuf)
  if res.nil?
    raise "No fields for table " + tableName + " found"
  end

  fields = r.map{|row| row.values[0]}
  if fields.empty?
    STDERR.puts "Table not found: #{tableName}\n"
  end
  res.clear
  fields
end


def populateAudTables(db, audTables)
  for tableIdx in 0 ... audTables.size
    query = "insert into " + audTables[tableIdx] + " ("

    fields = getTableFields(db, audTables[tableIdx])
    for fieldIdx in 0 ... fields.size
      query += fields[fieldIdx]
      if (fieldIdx != (fields.size-1))
        query += ", "
      end
    end
    query += ") "
    query += "select "

    for fieldIdx in 0 ... fields.size
      field = fields[fieldIdx]
      if (field == 'rev')
        query += $newrevid
      elsif (field == 'revtype')
        query += "0"
      else
        query += fields[fieldIdx]
      end
      if (fieldIdx != (fields.size-1))
        query += ", "
      end
    end
    query += " from "
    query += audTables[tableIdx].reverse.sub('_aud'.reverse, '').reverse

    puts query
    db.exec(query)
  end
end

def clearTables(db, audTables)
  for tableIdx in 0 ... audTables.size
    query = "delete from " + audTables[tableIdx];
    puts query
    db.exec(query)
  end
end

def populateRevInfoTable(db)
  query = "delete from revinfo"
  puts query
  db.exec(query)

  query = "select nextval ('hibernate_sequence')"
  puts query
  res = db.exec(query)
  if res == nil
    raise "Sequence " + hibernate_sequence + " not found"
  end
  $newrevid = '0'

  #$newrevid = res.getvalue(0, 0)
  #puts "New revid is " + $newrevid

  query = "INSERT INTO revinfo(rev, timestamp) VALUES($1::int, $2::bigint)"
  puts query
  db.exec query, [$newrevid, (Time.now.to_ms)]
end

def getAudTables(db, pattern)
  tablelist = []

  query = "SELECT relname FROM pg_class, pg_user WHERE usesysid = relowner "
  query += "AND ( relkind = 'r') AND relname !~ '^pg_' AND relname like '" + pattern + "' "
  query += "ORDER BY relname "

  res = db.exec(query)
  if res == nil
    return
  end
  nColumns = res.num_tuples
  if nColumns > 0
    for i in 0..res.num_tuples-1
      tablelist.push(res.getvalue(i, res.fnumber("relname")))
    end
    res.clear()
  else
    printf(STDERR, "Couldn't find any tables!\n")
  end
  return tablelist
end

if __FILE__ == $0
  # db = dbConnect('localhost', 'wdb', 'wdb', 'wdb-dev')
  db = dbConnect('localhost', 'wdb', 'wdb', 'wdbtest')

  audTables = getAudTables(db, "%_aud")

  clearTables(db, audTables)
  populateRevInfoTable(db)
  populateAudTables(db, audTables)

end