#!/usr/bin/env ruby

# Build yaml files which provide arguments passed to {lv,pv,vg}s and subsequent
# type conversions.
#
# ./generate_field_data ~/LVM2.2.02.38

require 'fileutils'
require 'yaml'

VERSION_FILE = "/VERSION"
COLUMNS_FILE = "/lib/report/columns.h"

debug = false 

TYPE_CONVERSION_MAP = {
 # Only types we can really trust
 "uint32" => "Integer",
 "int32" => "Integer",
 # These were determined by reading the code, they invoke _(u)int32_disp right away
 "pvmdas" => "Integer",
 "vgmdas" => "Integer",
 "lvcount" => "Integer",
 "lvsegcount" => "Integer",
 "segstartpe" => "Integer",
 # listed to return STR?
 "lvkmaj" => "Integer",
 "lvkmin" => "Integer",
 "snpercent" => "Float",
 "copypercent" => "Float",
 # size32/64, these do unit formatting unless overridden on command line. We
 # typically want them in bytes so we can convert them to Integers safely
 "size32" => "Integer",
 "size64" => "Integer",
 # These types return size32/size64 as well
 "lvkreadahead" => "Integer",
 "pvsize" => "Integer",
 "devsize" => "Integer",
 "originsize" => "Integer",
 "pvfree" => "Integer",
 "pvused" => "Integer",
 "pvmdafree" => "Integer",
 "pvmdasize" => "Integer",
 "vgsize" => "Integer",
 "vgfree" => "Integer",
 "vgmda_free" => "Integer",
 "chunksize" => "Integer",
 "segstart" => "Integer",
 "segsize" => "Integer",
 "snapcount" => "Integer",
 "vgmdafree" => "Integer",
 "vgmdasize" => "Integer",
 # Weird one, can be "auto" or size32
 "lvreadahead" => "String",
 "lvmetadatasize" => "Integer",
 "datapercent" => "Float",
 "metadatapercent" => "Float",
 "pvmdasused" => "Integer",
 "vgmdasused" => "Integer",
 "vgmdacopies" => "Integer",
 "thincount" => "Integer",
 "thinid" => "Integer",
 "discards" => "Integer",
 "thinzero" => "Integer",
 "transactionid" => "Integer",
 "raidmismatchcount" => "Integer",
 "raidwritebehind" => "Integer",
 "raidminrecoveryrate" => "Integer",
 "raidmaxrecoveryrate" => "Integer",
 "segsizepe" => "Integer",
 "thinid" => "Integer",
 # New fields for caching
 "cache_total_blocks" => "Integer",
 "cache_used_blocks" => "Integer",
 "cache_dirty_blocks" => "Integer",
 "cache_read_hits" => "Integer",
 "cache_read_misses" => "Integer",
 "cache_write_hits" => "Integer",
 "cache_write_misses" => "Integer"
}

lvm_source = ARGV[0]

version = File.readlines(lvm_source + VERSION_FILE)[0].split(' ')[0]

lvs     = []
lvssegs = []
pvs     = []
pvssegs = [] 
vgs     = []
File.readlines(lvm_source + COLUMNS_FILE).each do |line|
  # eg: FIELD(LVS, lv, STR, "LV UUID", lvid.id[1], 38, uuid, "lv_uuid", "Unique identifier")
  if line =~ %r{^FIELD\((.*)\)$}
    fields = $1.split(', ')
    fields.each { |f| f.gsub!(%r{^"}, ''); f.gsub!(%r{"$}, '') }
    p fields if debug
    app           = fields[0]
    general_type  = fields[2]
    specific_type = fields[6]
    column        = fields[7]
    method        = fields[7].dup
    description   = fields[8]
    p app, general_type, specific_type, column, method, description if debug

    if ["NUM", "SIZ"].include?(general_type)
      attribute_type = TYPE_CONVERSION_MAP[specific_type]
      if attribute_type.nil?
        puts "Oops, missing type conversion data of column '#{specific_type}' use by '#{app}' which says its going to return a '#{specific_type}'"
        puts "Figure out the missing type and rerun."
        exit 1
      end
    else
      attribute_type = "String"
    end

    # our shorter nicer method names, according to the man page these can be
    # dropped when passing column names as arguments as well, but i found a few
    # with issues (seg_start).
    case app
    when "LVS", "LVSINFOSTATUS"
      method.sub!(%r{^lv_}, '') 
    when "SEGS"
      method.sub!(%r{^seg_}, '') 
    when "LABEL"
      method.sub!(%r{^pv_}, '')
    when "PVS"
      method.sub!(%r{^pv_}, '') 
    when "PVSEGS"
      method.sub!(%r{^pvseg_}, '') 
    when "VGS"
      method.sub!(%r{^vg_}, '') 
    end

    attribute = { 
      :method => method, 
      :column => column, 
      :type_hint => attribute_type, 
      :description => description 
    }

    case app
    when "LVS", "LVSINFOSTATUS"
      lvs << attribute
    when "SEGS"
      lvssegs << attribute
    when "LABEL"
      pvs << attribute
    when "PVS"
      pvs << attribute
    when "PVSEGS"
      pvssegs << attribute
    when "VGS"
      vgs << attribute
    end
  end
end

# we use vg_uuid as our crossover attribute that links vg->lv and vg->pv
attribute = { :method => "vg_uuid", 
              :column => "vg_uuid", 
              :type_hint => "String", 
              :description => "For VolumeGroup to LogicalVolume relationship." }
lvs << attribute
attribute = { :method => "vg_uuid", 
              :column => "vg_uuid", 
              :type_hint => "String", 
              :description => "For VolumeGroup to PhysicalVolume relationship." }
pvs << attribute

# and we link lv->lvsegment, pv->pvsegment
attribute = { :method => "lv_uuid", 
              :column => "lv_uuid", 
              :type_hint => "String", 
              :description => "For LogicalVolume to LogicalVolumeSegment relationship." }
lvssegs << attribute
attribute = { :method => "pv_uuid", 
              :column => "pv_uuid", 
              :type_hint => "String", 
              :description => "For PhysicalVolume to PhysicalVolumeSegment relationship." }
pvssegs << attribute

lvs.sort!     {|x,y| x[:column] <=> y[:column]}
lvssegs.sort! {|x,y| x[:column] <=> y[:column]}
pvs.sort!     {|x,y| x[:column] <=> y[:column]} 
pvssegs.sort! {|x,y| x[:column] <=> y[:column]} 
vgs.sort!     {|x,y| x[:column] <=> y[:column]}

FileUtils.mkdir(version)

disclaimer=<<go
# These are column to object attribute mappings
# generated by #{$0} based on
# #{lvm_source}/lib/report/columns.h
go

File.open("#{version}/lvs.yaml", "w")    { |f| f.write(disclaimer); f.write(lvs.to_yaml)    }
File.open("#{version}/lvsseg.yaml", "w") { |f| f.write(disclaimer); f.write(lvssegs.to_yaml)}
File.open("#{version}/pvs.yaml", "w")    { |f| f.write(disclaimer); f.write(pvs.to_yaml)    }
File.open("#{version}/pvsseg.yaml", "w") { |f| f.write(disclaimer); f.write(pvssegs.to_yaml)}
File.open("#{version}/vgs.yaml", "w")    { |f| f.write(disclaimer); f.write(vgs.to_yaml)    }

puts "Done."