#!/bin/bash
set -e

echo '=== TRI REGENERATION WITH MAX-AGGREGATION FOR LOW ZOOMS ==='
echo "Start: $(date)"

TMP='/tmp/tri_gen'
SRTM_DIR='/home/slin/enduro-trails/data/srtm'
TERRAIN_DIR='/home/slin/enduro-trails/data/terrain'
TRI_DIR="${TERRAIN_DIR}/tri"

mkdir -p $TMP

echo ''
echo '=== Step 1: Check tri_raw_full.tif ==='
if [ -f "$TMP/tri_raw_full.tif" ]; then
  echo "tri_raw_full.tif exists:"
  gdalinfo -stats $TMP/tri_raw_full.tif 2>&1 | grep -E "Size|STATISTICS" || true
else
  echo "tri_raw_full.tif NOT FOUND — regenerating from SRTM..."
  find $SRTM_DIR -name '*.hgt' > $TMP/hgt_list.txt
  echo "HGT files: $(wc -l < $TMP/hgt_list.txt)"
  gdalbuildvrt -vrtnodata -32768 -overwrite -input_file_list $TMP/hgt_list.txt $TMP/srtm.vrt
  gdaldem TRI $TMP/srtm.vrt $TMP/tri_raw_full.tif -of GTiff -co COMPRESS=LZW -co BIGTIFF=YES -compute_edges
  echo "TRI computed:"
  gdalinfo -stats $TMP/tri_raw_full.tif 2>&1 | grep -E "Size|STATISTICS" || true
fi

echo ''
echo '=== Step 2: Add overviews with MAX resampling ==='
# Check GDAL version for -r max support
GDAL_VER=$(gdal-config --version 2>/dev/null || gdalinfo --version | grep -oP '\d+\.\d+')
echo "GDAL version: $GDAL_VER"

# Try gdaladdo -r max
if gdaladdo -r max --config COMPRESS_OVERVIEW LZW $TMP/tri_raw_full.tif 2 4 8 16 32 64 2>&1; then
  echo "Overviews with MAX added successfully"
  gdalinfo $TMP/tri_raw_full.tif 2>&1 | grep -i "overview" || true
else
  echo "gdaladdo -r max FAILED — using gdalwarp fallback"
  # Fallback: create a low-res version with max resampling
  gdalwarp -r max \
    -tr 0.01 0.01 \
    $TMP/tri_raw_full.tif \
    $TMP/tri_raw_lowres.tif \
    -co COMPRESS=LZW -overwrite
  echo "Low-res TRI created:"
  gdalinfo -stats $TMP/tri_raw_lowres.tif 2>&1 | grep -E "Size|STATISTICS" || true
fi

echo ''
echo '=== Step 3: Color relief (v5 ramp, threshold 15) ==='
cat > $TMP/tri_color_max.txt << 'RAMP'
nv    0    0    0    0
0     0    0    0    0
14    0    0    0    0
15    255  255  100  60
20    255  230  50   100
25    255  200  0    140
30    255  150  0    180
40    255  100  0    200
50    230  50   0    220
65    200  0    0    235
80    180  0   50    245
100   150  0   100   255
RAMP

gdaldem color-relief \
  $TMP/tri_raw_full.tif \
  $TMP/tri_color_max.txt \
  $TMP/tri_colored_max.tif \
  -alpha \
  -of GTiff \
  -co COMPRESS=LZW \
  -co BIGTIFF=YES

echo "Colored TRI created:"
gdalinfo -stats $TMP/tri_colored_max.tif 2>&1 | grep STATISTICS_MAX || true

echo ''
echo '=== Step 3-alt: Add overviews to colored file (max on RGBA) ==='
gdaladdo -r max --config COMPRESS_OVERVIEW LZW $TMP/tri_colored_max.tif 2 4 8 16 32 64 2>&1 || true
echo "Overviews on colored file:"
gdalinfo $TMP/tri_colored_max.tif 2>&1 | grep -i "overview" || true

echo ''
echo '=== Step 4: Generate tiles ==='
rm -rf ${TRI_DIR}
mkdir -p ${TRI_DIR}

gdal2tiles.py \
  --zoom=5-12 \
  --processes=4 \
  --tilesize=256 \
  --resampling=average \
  --webviewer=none \
  $TMP/tri_colored_max.tif \
  ${TRI_DIR}/

echo ''
echo '=== Step 5: Stats ==='
for z in 5 6 7 8 9 10 11 12; do
  total=$(find ${TRI_DIR}/$z/ -name '*.png' 2>/dev/null | wc -l)
  nonempty=$(find ${TRI_DIR}/$z/ -name '*.png' -size +400c 2>/dev/null | wc -l)
  echo "  zoom $z: $total total, $nonempty non-empty"
done

echo ''
echo '=== Step 6: Sample tile check ==='
TILE=$(find ${TRI_DIR}/7/ -name '*.png' -size +1000c 2>/dev/null | head -1)
if [ -n "$TILE" ]; then
  echo "Sample tile: $TILE"
  python3 -c "from PIL import Image; im=Image.open('$TILE'); print('Size:', im.size, 'Mode:', im.mode, 'Extrema:', im.getextrema())" 2>/dev/null || file "$TILE"
else
  echo "No non-empty tiles found at zoom 7!"
fi

echo ''
echo '=== Step 7: Average tile size at zoom 7 ==='
find ${TRI_DIR}/7/ -name '*.png' -size +400c -exec ls -la {} \; 2>/dev/null | awk '{sum+=$5; n++} END {if(n>0) print "avg:", sum/n, "bytes, count:", n; else print "no tiles"}'

echo ''
du -sh ${TRI_DIR}
echo '=== DONE ==='
echo "End: $(date)"