#!/bin/bash
set -e
GDALCOPYPROJ="/usr/share/doc/python-gdal/examples/gdalcopyproj.py"

# Expected directory names: 2010-04, 2010-11, ... 2016-04
OSSV_EDITIONS=($(ls -d 201*|sort -n))
OSSV_EDITIONS_LENGTH=${#OSSV_EDITIONS[@]}

OSSV_EDITIONS_TMP=$(mktemp -d --suffix=osstvw_edit)
function cleanup {
  rm -rf "${OSSV_EDITIONS_TMP}"
}
trap cleanup EXIT

# Create OSSTVW ocean blue to compare new files against
convert -size 5000x5000 xc:'#e6f6ff' -depth 8 ${OSSV_EDITIONS_TMP}/blue.png

# Outer loop (compare from)
for (( i=0; i<${OSSV_EDITIONS_LENGTH}; i++ )); do
  # Inner loop (compare to)
  for (( o=${i}; o<${OSSV_EDITIONS_LENGTH}; o++ )); do
    # Skip when outer == inner edition
    if [ "$i" != "$o" ]; then
      OSSV_DIFF_NAME="diff-${OSSV_EDITIONS[$i]}-${OSSV_EDITIONS[$o]}"
      mkdir -p "${OSSV_DIFF_NAME}"
      # TIF file loop for edition - see end of loop for find
      while IFS= read -r -d $'\0' FILE; do
        FILE_1="${OSSV_EDITIONS[$i]}/${FILE}"
        FILE_2="${OSSV_EDITIONS[$o]}/${FILE}"
        if [ ! -f "${FILE_1}" ]; then
          FILE_1="${OSSV_EDITIONS_TMP}/blue.png"
        fi
        # Skip existing files
        if [ ! -f "${OSSV_DIFF_NAME}/${FILE}" ]; then
          echo Creating diff ${OSSV_EDITIONS[$i]} ${OSSV_EDITIONS[$o]} "${FILE_1}" "${OSSV_DIFF_NAME}/${FILE}"
          # Background compare + gdalcopyproj
          ((compare -quiet "${FILE_1}" "${FILE_2}" -compose Src -highlight-color Red -lowlight-color 'rgba(255,255,255,0)' -define tiff:tile-geometry=512x512 "${OSSV_DIFF_NAME}/${FILE}" || true) && python ${GDALCOPYPROJ} "${FILE_2}" "${OSSV_DIFF_NAME}/${FILE}" ) &

          # Check how many background processes and wait if exceed
          running=($(jobs -rp))
          while [ ${#running[@]} -ge 16 ] ; do
            sleep 1   # this is not optimal, but you can't use wait here
            running=($(jobs -rp))
          done
        fi
      done < <(find "${OSSV_EDITIONS[$o]}" -maxdepth 1 -name '*.tif' -printf '%f\0')
    fi
  done
done