#!/usr/bin/env bash
# Pre-cache OSM tiles for the trip's map extent through the local proxy
# (which stores them in mock/.tilecache). Usage:
#   pre-cache-tiles.sh                    # all trips
#   pre-cache-tiles.sh colombia z16      # one trip, one zoom
set -euo pipefail
cd "$(dirname "$0")/.."
BASE="${BASE:-http://localhost:8077}"
TRIPS=("$@")
[ ${#TRIPS[@]} -eq 0 ] && TRIPS=(colombia boston florence)

# tile range for a lon/lat box
range() { # z minlon minlat maxlon maxlat -> "x0 x1 y0 y1"
  python3 -c "
import math
z, minlo, minla, maxlo, maxla = float('$1'), float('$2'), float('$3'), float('$4'), float('$5')
def tx(lon): return int((lon + 180) / 360 * 2**z)
def ty(lat):
    r = math.radians(lat)
    return int((1 - math.log(math.tan(r) + 1 / math.cos(r)) / math.pi) / 2 * 2**z)
print(tx(minlo), tx(maxlo), ty(maxla), ty(minla))"
}

fetch() { # trip z
  local trip="$1" z="$2"
  case "$trip" in
    colombia)
      # Cartagena + Santa Marta boxes
      for box in "-75.62 10.36 -75.42 10.48" "-74.27 11.08 -74.13 11.28"; do
        set -- $box
        read -r x0 x1 y0 y1 <<< "$(range "$z" "$1" "$2" "$3" "$4")"
        echo "  $trip z$z box($1,$2,$3,$4): x $x0-$x1 y $y0-$y1" >&2
        for ((x=x0; x<=x1; x++)); do for ((y=y0; y<=y1; y++)); do
          echo "$BASE/tiles/$z/$x/$y.png"
        done; done
      done
      ;;
    boston)
      set -- -71.16 42.29 -71.00 42.41
      read -r x0 x1 y0 y1 <<< "$(range "$z" "$1" "$2" "$3" "$4")"
      for ((x=x0; x<=x1; x++)); do for ((y=y0; y<=y1; y++)); do
        echo "$BASE/tiles/$z/$x/$y.png"
      done; done
      ;;
    florence)
      set -- 11.19 43.72 11.32 43.80
      read -r x0 x1 y0 y1 <<< "$(range "$z" "$1" "$2" "$3" "$4")"
      for ((x=x0; x<=x1; x++)); do for ((y=y0; y<=y1; y++)); do
        echo "$BASE/tiles/$z/$x/$y.png"
      done; done
      ;;
  esac
}

for trip in "${TRIPS[@]}"; do
  for z in 14 15 16; do
    echo "== $trip z$z"
    # one URL per curl: -o applies to the first URL only, otherwise the rest
    # print to stdout
    fetch "$trip" "$z" | xargs -P 8 -n 1 curl -s -o /dev/null -m 20 --retry 2 > /dev/null
  done
done
echo "done. cache size: $(du -sh .tilecache | cut -f1)"