# Script adds a table back to a running hbase.
# Currently only works on a copied aside table.
# You cannot parse arbitrary table name.
# 
# To see usage for this script, run: 
#
#  ${HBASE_HOME}/bin/hbase org.jruby.Main addtable.rb
#
include Java
import org.apache.hadoop.hbase.util.Bytes
import org.apache.hadoop.hbase.HConstants
import org.apache.hadoop.hbase.HRegionInfo
import org.apache.hadoop.hbase.client.HTable
import org.apache.hadoop.hbase.client.Delete
import org.apache.hadoop.hbase.client.Put
import org.apache.hadoop.hbase.client.Scan
import org.apache.hadoop.hbase.HTableDescriptor
import org.apache.hadoop.hbase.HBaseConfiguration
import org.apache.hadoop.hbase.util.FSUtils
import org.apache.hadoop.hbase.util.Writables
import org.apache.hadoop.fs.Path
import org.apache.hadoop.fs.FileSystem
import org.apache.commons.logging.LogFactory

# Name of this script
NAME = "add_table"

# Print usage for this script
def usage
  puts 'Usage: %s.rb TABLE_DIR [alternate_tablename]' % NAME
  exit!
end

# Get configuration to use.
c = HBaseConfiguration.new()

# Set hadoop filesystem configuration using the hbase.rootdir.
# Otherwise, we'll always use localhost though the hbase.rootdir
# might be pointing at hdfs location.
c.set("fs.default.name", c.get(HConstants::HBASE_DIR))
fs = FileSystem.get(c)

# Get a logger and a metautils instance.
LOG = LogFactory.getLog(NAME)

# Check arguments
if ARGV.size < 1 || ARGV.size > 2
  usage
end

# Get cmdline args.
srcdir = fs.makeQualified(Path.new(java.lang.String.new(ARGV[0])))

# Get table name
tableName = nil
if ARGV.size > 1
  tableName = ARGV[1]
  raise IOError("Not supported yet")
elsif
  # If none provided use dirname
  tableName = srcdir.getName()
end
HTableDescriptor.isLegalTableName(tableName.to_java_bytes)

# Figure locations under hbase.rootdir 
# Move directories into place; be careful not to overwrite.
rootdir = FSUtils.getRootDir(c)
tableDir = fs.makeQualified(Path.new(rootdir, tableName))

# If a directory currently in place, move it aside.
if srcdir.equals(tableDir)
  LOG.info("Source directory is in place under hbase.rootdir: " + srcdir.toString());
elsif fs.exists(tableDir)
  movedTableName = tableName + "." + java.lang.System.currentTimeMillis().to_s
  movedTableDir = Path.new(rootdir, java.lang.String.new(movedTableName))
  LOG.warn("Moving " + tableDir.toString() + " aside as " + movedTableDir.toString());
  raise IOError.new("Failed move of " + tableDir.toString()) unless fs.rename(tableDir, movedTableDir)
  LOG.info("Moving " + srcdir.toString() + " to " + tableDir.toString());
  raise IOError.new("Failed move of " + srcdir.toString()) unless fs.rename(srcdir, tableDir)
end

# Clean mentions of table from .META.
# Scan the .META. and remove all lines that begin with tablename
LOG.info("Deleting mention of " + tableName + " from .META.")
metaTable = HTable.new(c, HConstants::META_TABLE_NAME)
scan = Scan.new(tableName.to_java_bytes)
scanner = metaTable.getScanner(scan)
# Use java.lang.String doing compares.  Ruby String is a bit odd.
tableNameStr = java.lang.String.new(tableName)
while (result = scanner.next())
  rowid = Bytes.toString(result.getRow())
  rowidStr = java.lang.String.new(rowid)
  if not rowidStr.startsWith(tableNameStr)
    # Gone too far, break
    break
  end
  LOG.info("Deleting row from catalog: " + rowid);
  d = Delete.new(result.getRow())
  metaTable.delete(d)
end
scanner.close()

# Now, walk the table and per region, add an entry
LOG.info("Walking " + srcdir.toString() + " adding regions to catalog table")
statuses = fs.listStatus(srcdir)
for status in statuses
  next unless status.isDir()
  next if status.getPath().getName() == "compaction.dir"
  regioninfofile =  Path.new(status.getPath(), ".regioninfo")
  unless fs.exists(regioninfofile)
    LOG.warn("Missing .regioninfo: " + regioninfofile.toString())
    next
  end
  is = fs.open(regioninfofile) 
  hri = HRegionInfo.new()
  hri.readFields(is)
  is.close() 
  # TODO: Need to redo table descriptor with passed table name and then recalculate the region encoded names.
  p = Put.new(hri.getRegionName())
  p.add(HConstants::CATALOG_FAMILY, HConstants::REGIONINFO_QUALIFIER, Writables.getBytes(hri))
  metaTable.put(p)
  LOG.info("Added to catalog: " + hri.toString())
end