#!/bin/sh
#
# usage:
# find $somedir -type f -exec imagedate2filename.sh {} \;

NAME="$(basename "$1")"
EXT="$(echo ${NAME##*.} | tr '[:upper:]' '[:lower:]')"
DIR="$(dirname "$1")"

[ "$EXT" == "jpeg" ] && EXT=jpg

# don't fiddle with file names that look right already
SED0="$(echo "$NAME" | sed -n "/^[12][09][90-4][0-9]-[0-1][0-9]-[0-3][0-9]_[0-5][0-9]-[0-5][0-9]-[0-5][0-9]-[a-z]\{3\}\.$EXT/p")"
if [ ! -z "$SED0" ]
then
    echo "Skipping - matches name pattern already ($NAME)"
    exit 0
fi

# find dates in exif data
EXIFDATES="$(exiftool -q -q \
                 -p '$modifyDate' \
                 -p '$createDate' \
                 -p '$dateTimeOriginal' \
                 -p '$FileModifyDate' \
                 "$1" \
           | cut -b 1-19 \
           | grep "^20" \
           | tr '_' '0' \
           | tr ':' '-' \
           | tr ' ' '_' \
       )"

# find dates in the filename
# yyyy-mm-dd_hh-mm-ss
SED1="$(echo "$NAME" | sed -n 's/.*\([12][09][90-4][0-9]\)-\([0-1][0-9]\)-\([0-3][0-9]\)_\([0-5][0-9]\)-\([0-5][0-9]\)-\([0-5][0-9]\).*/\1-\2-\3_\4-\5-\6/p')"
# yyyymmdd_hhmmss
SED2="$(echo "$NAME" | sed -n 's/.*\([12][09][90-4][0-9]\)\([0-1][0-9]\)\([0-3][0-9]\)_\([0-5][0-9]\)\([0-5][0-9]\)\([0-5][0-9]\).*/\1-\2-\3_\4-\5-\6/p')"
# yyyymmddhhmmss
SED3="$(echo "$NAME" | sed -n 's/.*\([12][09][90-4][0-9]\)\([0-1][0-9]\)\([0-3][0-9]\)\([0-5][0-9]\)\([0-5][0-9]\)\([0-5][0-9]\).*/\1-\2-\3_\4-\5-\6/p')"

# yyyy-mm-dd_hh.mm.ss
SED4="$(echo "$NAME" | sed -n 's/.*\([12][09][90-4][0-9]\)-\([0-1][0-9]\)-\([0-3][0-9]\)_\([0-5][0-9]\)\.\([0-5][0-9]\)\.\([0-5][0-9]\).*/\1-\2-\3_\4-\5-\6/p')"

# yyyy-mm-dd hh.mm.ss
SED5="$(echo "$NAME" | sed -n 's/.*\([12][09][90-4][0-9]\)-\([0-1][0-9]\)-\([0-3][0-9]\) \([0-5][0-9]\)\.\([0-5][0-9]\)\.\([0-5][0-9]\).*/\1-\2-\3_\4-\5-\6/p')"

# yyyy-mm dd_hh-mm-ss
SED6="$(echo "$NAME" | sed -n 's/.*\([12][09][90-4][0-9]\)-\([0-1][0-9]\)-\([0-3][0-9]\) \([0-5][0-9]\)-\([0-5][0-9]\)-\([0-5][0-9]\).*/\1-\2-\3_\4-\5-\6/p')"

# pick the oldest one
PICK="$(for d in $EXIFDATES $SED1 $SED2 $SED3 $SED4 $SED5 $SED6; do echo $d; done | sort -u | head -1)"

# put info on screen and rename
echo "Dates for: $1"

for e in $EXIFDATES
do echo "From EXIF:     " $e; done

for f in $SED1 $SED2 $SED3 $SED4 $SED5 $SED6
do echo "From Filename: " $f; done

if [ -z "$PICK" ]
then
    echo "Skipping - no dates found"
else
    NEWNAME="$DIR/$PICK-$(pwgen -A -0 -1 3).$EXT"
    echo mv "$1" "$NEWNAME"
    mv "$1" "$NEWNAME"
fi
echo