#!/usr/bin/env bash
#
# pre-process-media.sh v2022-08-01
#
# Prepare a directory of images and videos for long-term archival by normalizing
# their names, optimizing JPEGs with jpeg-archive, and stripping embedded MP4s
# from Android Motion Photos.
#
# SPDX-License-Identifier: GPL-3.0-only

# Changes:
#
# v2022-08-01: fix minor syntax issue
# v2022-01-15: support Pixel panorama images
# v2021-12-26: add 'ftypiso6' for Nokia Android 9 MVIMG files, anchor regexes to
#              beginning of line to prevent renaming files prematurely.

# Exit on first error
set -o errexit

if [[ -z "$1" ]]; then
    echo "No target directory specified."

    exit 1
fi

echo "Preprocessing images and videos in $1"

# Change to the input file's directory
pushd "$1" >/dev/null

echo "Changing permissions to 640..."
find . -type f -exec chmod 640 {} \;

# Rename IMG_20210217_204834.jpg to 2021-02-17_204834.jpg
echo "Renaming images to ISO 8601 and removing IMG_..."
perl-rename 's/^IMG_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.jpg/$1-$2-$3_$4.jpg/' *.jpg
perl-rename 's/^IMG_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.JPG/$1-$2-$3_$4.jpg/' *.JPG
perl-rename 's/^IMG_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.jpeg/$1-$2-$3_$4.jpg/' *.jpeg
perl-rename 's/^IMG_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.JPEG/$1-$2-$3_$4.jpg/' *.JPEG
# Rename 20220501_174346.jpg (Samsung A52)
perl-rename 's/^([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.jpg/$1-$2-$3_$4.jpg/' *.jpg
# Rename IMG_2180.HEIC to 2180.HEIC (iPhone)
perl-rename 's/^IMG_([0-9]{4}).HEIC/$1.heic/' *.HEIC
# Rename PXL_20210717_043834784.jpg to 2021-07-17_043834784.jpg (Pixel)
perl-rename 's/^PXL_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.jpg/$1-$2-$3_$4.jpg/' *.jpg

# Remove embedded MP4s from Pixel motion images. Depending on the Android vers-
# ion the MP4 header could be ftypmp42, ftypmp4, ftypisom, etc. We have to check
# each one in succession, but note that grep will return a non-zero exit code
# if it doesn't find the pattern, so we need to temporarily disable errexit. To
# make matters worse, it seems some images are called MP and appear to contain
# multiple images in the Android Photos app, but don't contain an MP4!
#
# See: https://stackoverflow.com/questions/53104989/how-to-extract-the-photo-video-component-of-a-mvimg
# See: https://medium.com/android-news/working-with-motion-photos-da0aa49b50c
# See: https://linuxreviews.org/Google_Pixel_%22Motion_Photo%22
set +o errexit
for file in PXL_*.MP.jpg MVIMG_*.jpg; do
    # Don't crash when there are no files matching the glob
    [ -f "$file" ] || continue

    # Check MP4 header, newer versions first
    unset ofs
    for header in 'ftypisom' 'ftypmp4' 'ftypmp42' 'ftypiso6'; do
        ofs=$(grep -F --byte-offset --only-matching --text "$header" "$file")

        if [[ $ofs ]]; then
            ofs=${ofs%:*}
            truncate -s $((ofs-4)) "$file"

            # Go to next image
            break
        fi
    done
done

# Re-set exit on first error
set -o errexit

# Rename PXL_20210717_043834784.MP.jpg to 2021-07-17_043834784.jpg (Pixel Motion Images)
perl-rename 's/^PXL_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.MP\.jpg/$1-$2-$3_$4.jpg/' *.jpg

# Rename MVIMG_20190618_124507.jpg to 2019-06-18_124507.jpg (Android Motion Images)
perl-rename 's/^MVIMG_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.jpg/$1-$2-$3_$4.jpg/' *.jpg

# Rename PXL_20210910_193159741.NIGHT.jpg to 2021-09-10_193159741.jpg (Pixel Night mode)
perl-rename 's/^PXL_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.NIGHT\.jpg/$1-$2-$3_$4.jpg/' *.jpg

# Rename PXL_20211118_162823829.PORTRAIT.jpg to 2021-11-18_162823829.jpg (Pixel Portrait mode)
perl-rename 's/^PXL_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.PORTRAIT\.jpg/$1-$2-$3_$4.jpg/' *.jpg

# Rename PXL_20210925_150154460.PANO.jpg to 2021-09-25_150154460.jpg (Pixel Panorama mode)
perl-rename 's/^PXL_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.PANO\.jpg/$1-$2-$3_$4.jpg/' *.jpg

for file in *.heic; do
    [ -f "$file" ] || continue

    # We are going to rename the HEIC files according to their embedded dates,
    # but exiftool syntax is hard so I will just check if these files were al-
    # ready renamed and skip them. These files come from iPhones.
    if [[ ! $file =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{4}\.HEIC$ ]]; then
        # Rename file based on DateTimeOriginal EXIF tag and the original file
        # name (I removed the "IMG_" part with perl-rename first).
        exiftool '-filename<${DateTimeOriginal}_${FileName}' -d %Y-%m-%d "$file"
    fi
done

# Rename VID_20210205_112539.mp4 to 2021-02-05_112539.mp4
echo "Renaming videos to ISO 8601 and removing VID_..."
perl-rename 's/VID_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.mp4/$1-$2-$3_$4.mp4/' *.mp4
perl-rename 's/VID_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.MP4/$1-$2-$3_$4.mp4/' *.MP4

# Rename 20220502_124146.mp4 (Samsung A52)
perl-rename 's/^([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.mp4/$1-$2-$3_$4.mp4/' *.mp4

# Rename PXL_20210714_145336054.mp4 to 2021-07-14_145336054.mp4
perl-rename 's/PXL_([0-9]{4})([0-9]{2})([0-9]{2})_([0-9]+)\.mp4/$1-$2-$3_$4\.mp4/' *.mp4 

# Optimize JPEGs with jpeg-archive
find . -name '*.jpg' | chrt -b 0 parallel --no-notice "jpeg-recompress -q high {} {}" 

# Change back to our starting directory
popd >/dev/null

exit 0