#!/usr/bin/env bash
# tiles-build <out.pmtiles> <minzoom> <maxzoom> [tippecanoe options and inputs…] (roadmap 15.17c): one tippecanoe build,
# except that zooms below 7 get their own pass at a quarter of the detail (1,024 units a tile: about a pixel on screen)
# and at most 150 KB a tile (the smallest features dropped first), so a wide view of land, units or public land stays
# light on a phone. Zooms 7 and up are built exactly as asked; tile-join puts the two passes together.
set -euo pipefail
[[ $# -ge 3 ]] || { echo "usage: tiles-build <out.pmtiles> <minzoom> <maxzoom> [tippecanoe args…]" >&2; exit 2; }
out="$1" minzoom="$2" maxzoom="$3"
shift 3
LOW_TOP=6        # the last zoom of the light pass
LOW_DETAIL=10    # 2^10 units across a tile (tippecanoe's default is 12)
LOW_MAX_BYTES=150000

if (( minzoom > LOW_TOP )); then
  exec tippecanoe -o "$out" --force -Z"$minzoom" -z"$maxzoom" "$@"
fi
low="${out%.pmtiles}.low.pmtiles"
high="${out%.pmtiles}.high.pmtiles"
lowmax=$(( maxzoom < LOW_TOP ? maxzoom : LOW_TOP ))
# Options given after the caller's win, so the light pass's limits hold whatever the caller asked for.
tippecanoe -o "$low" --force -Z"$minzoom" -z"$lowmax" "$@" \
  --full-detail="$LOW_DETAIL" --low-detail="$LOW_DETAIL" --maximum-tile-bytes="$LOW_MAX_BYTES" --drop-smallest-as-needed
if (( maxzoom <= LOW_TOP )); then
  mv -f "$low" "$out"
  exit 0
fi
tippecanoe -o "$high" --force -Z$(( LOW_TOP + 1 )) -z"$maxzoom" "$@"
# Both passes carry the caller's name and credit; tile-join would join them ("X + X"), so it's given them once.
meta=()
for (( i = 1; i <= $#; i++ )); do
  case "${!i}" in
    -n|--name|-A|--attribution) j=$(( i + 1 )); meta+=("${!i}" "${!j}") ;;
    --name=*|--attribution=*) meta+=("${!i}") ;;
  esac
done
tile-join -o "$out" -f -q -pk "${meta[@]}" "$low" "$high" 2> >(grep -v 'mismatched maxzooms' >&2)
rm -f "$low" "$high"