#!/bin/bash

function checkJhead()
{
    local result
    local check=$(which ant)
    if [[ "$check" =~ ^/.* ]]; then
        echo "jhead requirement OK"
        result=1
    else
        echo "jhead requirement MISSING"
        result=0
    fi
    return $result
}

# main

# Lowercase extension.
uppercaseCount=$(find -maxdepth 1 -name '*.JPG' | wc -l)
if [[ $uppercaseCount > 0 ]]; then
   rename 's/JPG/jpg/' *.JPG
fi
echo ".JPG -> .jpg: $uppercaseCount"

# Rename.
checkJhead
if [[ $? == 1 ]]; then
    count=0
    for filename in $(ls *.jpg); do
        #echo "==== $filename"
        if [[ $(jhead $filename | grep Date) =~ ^Date.* ]]; then
           #echo "yop $filename"
           jhead -n%Y%m%d-%H%M%S "$filename"
           let "count+=1"
        fi
    done
    echo "Renamed: $count"
else
    echo "KO"
fi