#!/bin/bash

# cgrep--grep with context display and highlighted pattern matches

setglobal context = '0'
setglobal esc = '"^['"
setglobal boldon = ""$(esc)[1m"," boldoff = ""$(esc)[22m""
setglobal sedscript = ""/tmp/cgrep.sed.$Pid""
setglobal tempout = ""/tmp/cgrep.$Pid""

proc showMatches
{
  setglobal matches = '0'

  echo "s/$pattern/$(boldon)$pattern$(boldoff)/g" > $sedscript

  for lineno in [$[grep -n $pattern $1 | cut -d: -f1]]
  { 
    if test $context -gt 0  {
      setglobal prev = "$shExpr(' $lineno - $context ')"
      
      if test $prev -lt 1  {
         # This results in "invalid usage of line address 0".
        setglobal prev = '"1'"
      }
      setglobal next = "$shExpr(' $lineno + $context ')"

      if test $matches -gt 0  {
        echo "$(prev)i\\" >> $sedscript
        echo "----" >> $sedscript
      }
      echo "$(prev),$(next)p" >> $sedscript
    } else {
      echo "$(lineno)p" >> $sedscript
    }
    setglobal matches = "$shExpr(' $matches + 1 ')"
  }

  if test $matches -gt 0  {
    sed -n -f $sedscript $1 | uniq | more
  }
}

trap "$[which rm] -f $tempout $sedscript" EXIT 

if test -z $1  {
  echo "Usage: $0 [-c X] pattern {filename}" > !2; exit 0
}

if test $1 = "-c"  {
  setglobal context = $2
  shift; shift
} elif test $[echo $1|cut -c1-2] = "-c"  {
  setglobal context = $[echo $1 | cut -c3-]
  shift
}

setglobal pattern = $1;  shift

if test $Argc -gt 0  {for filename in @Argv { 
    echo "----- $filename -----"
    showMatches $filename
  }
} else {
  cat - > $tempout      # Save stream to a temp file.
  showMatches $tempout
}

exit 0