#!/bin/bash
#
# $Id$
#

# A string of spaces for indenting:
declare -a spaceSTR="                                                                   "
declare -a exchange_triplet

# In case we find a cirdular dependency, it has the form :
# parent->dependency_0->...->dependency_n->dependency_0
# If we want to build dependency_n before dependency_0,
# no problem: we just prune the tree at dependency_n.
# If we want to build first dependency_0, we need to
# put dependency_n as a dependency of parent. The triplet
# above shall contain (parent dependency_0 dependency_n)

#----------------------------#
generate_dependency_tree() { #
#----------------------------#
: <<inline_doc
    function:   Create a subtree of the dependency tree
                (recursive function)
    input vars: $1 : file with a list of targets
		     the first line of the file is an array
                     of links
    externals:  vars: BLFS_XML
		      DEP_LEVEL
    modifies:   vars: none
    returns:    nothing
    output:     files: for each pkg with dependencies in $1,
                       a file pkg.dep and its dependencies
    on error:   nothing
    on success: nothing
inline_doc

local DepFile=$1
local -a rootlink
local -a otherlink
local -i depth
local -i count=0
local id_of_dep
local parent
local lines_to_remove=
local srootlink
local dep_level

{
# BEWARE : the order of options matters : read -a -u6 rootlink hangs forever
# (actually, the doc says -a array -u fd)
# We use fd number 6 for input from DepFile, because we need 0 for user input
read -u6 -a rootlink
depth=${#rootlink[*]}
dep_level=$DEP_LEVEL
if (( $DEP_LEVEL > 2 )) && (( $depth > 1 )); then dep_level=2; fi
srootlink="${rootlink[*]} "
# start of Depfile
echo -en "\nNode: $depth${spaceSTR:0:$depth}${RED}$DepFile${OFF}"

while read -u6 id_of_dep; do
# count entries in file
  (( count++ ))
# Has this entry already been seen?
  if [ -f ${id_of_dep}.dep ]; then # found ${id_of_dep}.dep already in tree
    otherlink=($(head -n 1 ${id_of_dep}.dep))
    if [ -z "${otherlink[*]}" ] 
      then echo otherlink empty for $id_of_dep.dep
      echo This should not happen, but happens to happen...
      exit 1
    fi
# Do not use "${rootlink[*]}" =~ "${otherlink[*]}": case rootlink=(1 11)
# and otherlink=(1 1)
    if [[ ${srootlink#"${otherlink[*]} "} != ${srootlink} ]]; then # circular dep
# First look for the other parent of this dependency.
# The parent has the same link without the last entry.
# We do not need otherlink anymore so just destroy the last element
      unset otherlink[${#otherlink[*]}-1]
      parent=$(grep ^"${otherlink[*]}"\$ -l *)
      parent=${parent%.dep}
      echo -en "\nCirc: $depth${spaceSTR:0:$depth}${BLUE}Circular dependency detected:${OFF}"
      echo -en "\nCirc: $depth${spaceSTR:0:$depth}${BOLD}${id_of_dep}${OFF} is a dependency \
of ${BOLD}${parent}${OFF}"
      echo -en "\nCirc: $depth${spaceSTR:0:$depth}${BOLD}${DepFile%.dep}${OFF} is a dependency \
of ${BOLD}${id_of_dep}${OFF}"
      echo -en "\nCirc: $depth${spaceSTR:0:$depth}${BOLD}${id_of_dep}${OFF} is a dependency \
of ${BOLD}${DepFile%.dep}${OFF}"
# If idofdep is the parent of DepFile, we can exchange them if required
#      if grep -q ${DepFile%.dep} ${id_of_dep}.dep; then
# we propose exchange always
        echo -en "\nCirc: $depth${spaceSTR:0:$depth}Do you want to build ${id_of_dep} first? yes/no (no):"
        read ANSWER
        if [ x$ANSWER = "xyes" ] ; then  # exchange:
# set triplet and return 1
          exchange_triplet=($parent $id_of_dep ${DepFile%.dep})
          return 1
        else # no exchange: prune
          lines_to_remove="$lines_to_remove $id_of_dep"
        fi
#      else
#        lines_to_remove="$lines_to_remove $id_of_dep"
#      fi
    else # not circular: prune
      lines_to_remove="$lines_to_remove $id_of_dep"
    fi
    continue
  fi
  flag=true
  while [ $flag = true ]; do
    flag=false
    xsltproc --stringparam dependencies ${dep_level} \
        --stringparam idofdep $id_of_dep \
        -o ${id_of_dep}.dep \
        ../xsl/dependencies.xsl ../packages.xml

    if [[ -f ${id_of_dep}.dep ]]; then
      sort ${id_of_dep}.dep -o ${id_of_dep}.dep
      sed -i "1i${rootlink[*]} $count" ${id_of_dep}.dep
      generate_dependency_tree ${id_of_dep}.dep
# Test return value, in case we exchange dependencies
      case $? in
       0) # Normal return
         ;;
       1) # We are backing up to parent
         if [[ ${exchange_triplet} == ${DepFile%.dep} ]]
           then tree_erase ${id_of_dep}.dep
# Just doing a sed -i "s@${id_of_dep}@${exchange_triplet[2]}@" $DepFile
# is not good if $DepFile contains several times the same line
# so first find the first line and then sed
           lineno=$(sed -n /${id_of_dep}/= $DepFile | head -n1)
           sed -i "${lineno}s@${id_of_dep}@${exchange_triplet[2]}@" $DepFile
           id_of_dep=${exchange_triplet[2]}
           flag=true
         else
# echo backing up to ${exchange_triplet} at ${DepFile%.dep}
           return 1
         fi
         ;;
      esac
    else
      echo "${rootlink[*]} $count" > ${id_of_dep}.dep
    fi
  done
done
echo -en "\n End: $depth${spaceSTR:0:$depth}${GREEN}$DepFile${OFF}"
} 6<$DepFile
# It may happen that a file is created with several times
# the same line. Normally, all those lines but one
# would be flagged to be removed (or all of them if
# the dependency appeared before). a simple sed /$line/d
# destroys all the lines. We should instead remove
# only one for each appearance of it in lines_to_remove.
# so first get the number of first line and then delete
# that line
for line in $lines_to_remove
  do lineno=$(sed -n /^$line\$/= $DepFile | head -n1)
  sed -i ${lineno}d $DepFile
done
return 0
}

#---------------#
tree_browse() { #
#---------------#
local file=$1
local f

#echo file=$file
for f in $(grep '[^0-9 ]' $file); do
#  echo f=$f
  if grep -q '[^0-9 ]' ${f}.dep ; then
    tree_browse ${f}.dep
  fi
  echo $f
done
}

#--------------#
tree_erase() { #
#--------------#
local file=$1
local f
local -a rootlink
local -a rootlink2

#echo file=$file
rootlink=($(head -n1 $file))
for f in $(grep '[^0-9 ]' $file); do
#  echo "    f"=$f
  if [ -f ${f}.dep ]; then
    rootlink2=($(head -n1 ${f}.dep))
    if [[ "${rootlink2[*]}" =~ "${rootlink[*]}" ]] ; then
      tree_erase ${f}.dep
    fi
  fi
done
rm -f $file
}