#!/bin/bash

# Usage: jpg_2_metadata.sh FILE
#
# Dependencies:
#
#   * identify (ImageMagick or GraphicsMagick)
#
#   * exiftool
#
#   * units (GNU units)
#
#   * MagneticField (geographiclib-tools package)
#
#   * wmm dataset for MagneticField to work (installed with
#     geographiclib-get-magnetic from geographiclib-tools package)

imageurl="$1"
image="${imageurl##*/}"

SVGMIDDLE=800

printf "%s\n" "$1" >&2

## 1) Printing metadata from the JPEG file
printf "%s\n" "Metadata for the picture $image"
printf "%s\n" "identify -verbose $imageurl"
printf "%s\n" "--- BEGIN JPEG METADATA ---"
identify -verbose "$imageurl"
printf "%s\n" "--- END JPEG METADATA ---"
printf "%s\n" "exiftool $imageurl"
printf "%s\n" "--- BEGIN JPEG METADATA ---"
exiftool "$imageurl"
printf "%s\n" "--- END JPEG METADATA ---"

## 2) Calculating geographical position
# exiflatituderef=$(identify -format '%[exif:GPSLatitudeRef]\n' "$imageurl" 2>/dev/null)
exiflatituderef=$(exiftool -n '-exif:GPSLatitudeRef' "$imageurl" 2>/dev/null)
if [ "$exiflatituderef" == "N" ]; then
#    latituderef='+'
    latituderef=''
elif [ "$exiflatituderef" == "S" ]; then
    latituderef='-'
else
    printf "%s\n" "No GPS metadata, exiting" >&2;
    exit 0
fi

# exiflongituderef=$(identify -format '%[exif:GPSLongitudeRef]\n' "$imageurl" 2>/dev/null)
exiflongituderef=$(exiftool -n '-exif:GPSLongitudeRef' "$imageurl" 2>/dev/null)
if [ "$exiflongituderef" == "E" ]; then
#    longituderef='+'
    longituderef=''
elif [ "$exiflongituderef" == "W" ]; then
    longituderef='-'
else
    printf "%s\n" "No GPS metadata, exiting" >&2;
    exit 0
fi

# exifaltituderef=$(identify -format '%[exif:GPSAltitudeRef]\n' "$imageurl" 2>/dev/null)
exifaltituderef=$(exiftool -n '-exif:GPSAltitudeRef' "$imageurl" 2>/dev/null)
if [ "$exifaltituderef" == "0" ]; then
#    altituderef='+'
    altituderef=''
elif [ "$exifaltituderef" == "1" ]; then
    altituderef='-'
else
    printf "%s\n" "No GPS metadata, exiting" >&2;
    exit 0
fi

# exiflatitude=$(identify -format '%[exif:GPSLatitude]\n' "$imageurl")
# exiflatitude_d=$(echo $exiflatitude | cut -d"," -f1 | bc)
# exiflatitude_m=$(echo $exiflatitude | cut -d"," -f2 | bc)
# exiflatitude_s=$( echo "scale=10 ; $(echo $exiflatitude | cut -d"," -f3)" | bc)
# latitudenum=$(units "$exiflatitude_d deg + $exiflatitude_m arcmin + $exiflatitude_s arcsec" deg | head -n1 | cut -d' ' -f2)
latitudenum=$(exiftool -n '-exif:GPSLatitude' "$imageurl")

latitude=${latituderef}${latitudenum}

# exiflongitude=$(identify -format '%[exif:GPSLongitude]\n' "$imageurl")
# exiflongitude_d=$(echo $exiflongitude | cut -d"," -f1 | bc)
# exiflongitude_m=$(echo $exiflongitude | cut -d"," -f2 | bc)
# exiflongitude_s=$( echo "scale=10 ; $(echo $exiflongitude | cut -d"," -f3)" | bc)
# longitudenum=$(units "$exiflongitude_d deg + $exiflongitude_m arcmin + $exiflongitude_s arcsec" deg | head -n1 | cut -d' ' -f2)
longitudenum=$(exiftool -n '-exif:GPSLongitude' "$imageurl")

longitude=${longituderef}${longitudenum}

# exifaltitude=$(identify -format '%[exif:GPSAltitude]\n' "$imageurl")
# altitudenum=$(echo "scale=1 ; $exifaltitude" | bc)
altitudenum=$(exiftool -n '-exif:GPSAltitude' "$imageurl")

altitude=${altituderef}${altitudenum}

## 3) Calculating camera direction
# exifdirectionref=$(identify -format '%[exif:GPSImgDirectionRef]\n' "$imageurl" 2>/dev/null)
exifdirectionref=$(exiftool -n '-exif:GPSImgDirectionRef' "$imageurl" 2>/dev/null)
if [ "$exifdirectionref" == "T" ]; then
    directionref=0
elif [ "$exifdirectionref" == "M" ]; then
    d=$(date -I)
    directionref=$(echo ${d} ${latitude} ${longitude} ${altitude} | MagneticField | cut -d' ' -f 1)
else
    printf "%s\n" "No GPS (compass) metadata" >&2;
fi

# exifdirection=$(identify -format '%[exif:GPSImgDirection]\n' "$imageurl")
exifdirection=$(exiftool -n '-exif:GPSImgDirection' "$imageurl")
direction=$(echo "scale=2 ; ${directionref} + ${exifdirection}" | bc)

# convert degrees into radians and substract 90°
# (we turn clockwise starting from x axis)
# this is not the standard polar frame
directionrad=$(echo "scale=4 ; ${direction} * 2 * 3.14159/360 - 3.14159/2" | bc)

## 3.b) Calculating camera direction segment for svg

x1=${SVGMIDDLE}
y1=${SVGMIDDLE}
x2=$(echo "scale=4 ; ${x1} + ${SVGMIDDLE} * c(${directionrad})" | bc -l)
y2=$(echo "scale=4 ; ${y1} + ${SVGMIDDLE} * s(${directionrad})" | bc -l)

## 4) Calculating camera angle

photoangledeg2=$(exiftool -FOV "$imageurl" | awk '{ print $5 }')
photoanglerad2=$(echo "scale=4 ; ${photoangledeg2} * 2 * 3.14159 / 360" | bc)

# #################
# # obsolete code #
# exiffocallength=$(identify -format '%[exif:FocalLength]\n' "$imageurl")
# focal=$(echo $exiffocallength | cut -d'/' -f1)

# # The angle here has been measured by shooting a coordinate system
# # from a known distance, at different zoom levels
# if [ $focal -eq 450 ]; then
#     photoanglerad="0.4734" ;
# elif [ $focal -eq 1800 ]; then
#     photoanglerad="0.1636" ;
# elif [ $focal -gt 450 ] && [ $focal -lt 1800 ]; then
#     # The formula has been determined by applying a non-linear
#     # regression to recorded data
#     photoanglerad=$(echo "0.0000001545 * ${focal}^2 + -0.0005740 * ${focal} + 0.6983" | bc) ;
# else
#     photoanglerad="null" && printf "%s\n" "focal = $focal : unsupported case" >&2;
# fi

# photoanglerad=$(echo "2*${photoanglerad}" | bc)

# photoangledeg=$(echo "scale=4 ; ${photoanglerad} * 180 / 3.14159" | bc)
# #################

## 4.b) Calculating camera angle segments for svg

if [ ${photoanglerad2} != "null" ]; then
    # get the direction of the two lines
    # used to represent the camera angle
    dirangle1rad=$(echo "scale=4 ; ${directionrad} - 0.5*${photoanglerad2}" | bc)
    
    dirangle2rad=$(echo "scale=4 ; ${directionrad} + 0.5*${photoanglerad2}" | bc)

    x3=$(echo "scale=4 ; ${x1} + ${SVGMIDDLE} * c(${dirangle1rad})" | bc -l)
    y3=$(echo "scale=4 ; ${y1} + ${SVGMIDDLE} * s(${dirangle1rad})" | bc -l)
    x4=$(echo "scale=4 ; ${x1} + ${SVGMIDDLE} * c(${dirangle2rad})" | bc -l)
    y4=$(echo "scale=4 ; ${y1} + ${SVGMIDDLE} * s(${dirangle2rad})" | bc -l)
else
    printf "%s\n" "Won't calculate camera angle" >&2;
fi

osmurl="https://www.openstreetmap.org/#map=19/${latitude}/${longitude}"

geourl="geo:${latitude},${longitude},${altitude}"

printf "\n%s\n" "OSM URL: $osmurl"
printf "\n%s\n" "GEO URL: $geourl"
printf "\n%s\n" "Direction (clockwise angle from true North):"
printf "%s\n" "degrees: $direction"
printf "\n%s\n" "Photo angle:"
printf "%s\n" "degrees: $photoangledeg"
printf "%s\n" "radians: $photoanglerad"
printf "%s\n" "degrees: $photoangledeg2"
printf "%s\n" "radians: $photoanglerad2"
printf "\n%s\n" "A,B,C,D positions for svg generation:"
printf "%s\n" "A: ${x1} ${y1}"
printf "%s\n" "B: ${x2} ${y2}"
printf "%s\n" "C: ${x3} ${y3}"
printf "%s\n" "D: ${x4} ${y4}"