#!/bin/bash
set -e

echo '=== FULL TRI REGENERATION (32E-50E) ==='
echo "Start: $(date)"

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

echo ''
echo '=== Step 1: Merge all 101 HGT files ==='
ls $SRTM_DIR/*.hgt > $TMP/hgt_list.txt
echo "Files: $(wc -l < $TMP/hgt_list.txt)"

gdalbuildvrt -input_file_list $TMP/hgt_list.txt $TMP/merged_full.vrt
echo "VRT built"

echo ''
echo '=== Step 2: Compute TRI ==='
gdaldem TRI $TMP/merged_full.vrt $TMP/tri_raw_full.tif \
  -of GTiff -co COMPRESS=LZW -co BIGTIFF=YES
echo "TRI computed"

echo ''
echo '=== Step 3: Color relief (thresholds x1.3) ==='
cat > $TMP/tri_color_v3.txt << 'RAMP'
nv    0    0    0    0
0     0    0    0    0
3     0    0    0    0
4     255  255  100  60
5     255  230  50   100
6.5   255  200  0    140
9     255  150  0    180
13    255  100  0    200
20    230  50   0    220
26    200  0    0    235
39    180  0   50    245
65    150  0   100   255
RAMP

gdaldem color-relief \
  $TMP/tri_raw_full.tif \
  $TMP/tri_color_v3.txt \
  $TMP/tri_colored_full.tif \
  -alpha \
  -of GTiff \
  -co COMPRESS=LZW \
  -co BIGTIFF=YES
echo "Color relief done"

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

gdal2tiles.py \
  --zoom=5-12 \
  --processes=4 \
  --tilesize=256 \
  --webviewer=none \
  $TMP/tri_colored_full.tif \
  ${TRI_DIR}/
echo "Tiles generated"

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 ''
du -sh ${TRI_DIR}

# Also update merged_srtm.tif for future use
cp $TMP/tri_raw_full.tif $TMP/tri_raw.tif
gdal_translate -of GTiff -co COMPRESS=LZW $TMP/merged_full.vrt ${TERRAIN_DIR}/merged_srtm.tif

echo ''
echo '=== DONE ==='
echo "End: $(date)"