#!/usr/bin/env bash
# End-to-end driver for the FTB Chunks -> Xaero's World Map reveal transplant.
#
# See analysis/FTB-XAERO-MAP-MIGRATION.md for the reasoning. This script does the
# parts that can be automated; the singleplayer pass in step 3 has to be done by hand
# on a machine that can run the pack.
#
# Usage:
#   migrate-player.sh <player> <ftbchunks-data> <world-dir> [--dimension <id>] [--work <dir>]
#
#   <player>           label used for output paths, e.g. Stirwick
#   <ftbchunks-data>   that player's local/ftbchunks/data/<uuid>/, or a bare zip/dir
#                      of region files, or an already-extracted mask .json
#   <world-dir>        the world save containing region/
#
# Example:
#   tools/migrate-player.sh Stirwick ~/Stirwick-ftbchunks ~/server/world \
#       --dimension minecraft:overworld --work /var/tmp/xaero-migration

set -euo pipefail

here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

if [ $# -lt 3 ]; then
    sed -n '2,20p' "${BASH_SOURCE[0]}" | sed 's/^# \{0,1\}//'
    exit 2
fi

player="$1"; ftb="$2"; world="$3"; shift 3
dimension="minecraft:overworld"
work="$(pwd)/xaero-migration"

while [ $# -gt 0 ]; do
    case "$1" in
        --dimension) dimension="$2"; shift 2 ;;
        --work)      work="$2"; shift 2 ;;
        *) echo "unknown option: $1" >&2; exit 2 ;;
    esac
done

out="$work/$player"
mask="$out/mask.json"
sp="$out/sp-world"

echo "player     : $player"
echo "ftb data   : $ftb"
echo "world      : $world"
echo "dimension  : $dimension"
echo "output     : $out"
echo

if [ ! -d "$world/region" ]; then
    echo "error: $world/region not found" >&2
    exit 1
fi
mkdir -p "$out"

echo "== 1/2  extracting reveal mask =="
if [ "${ftb##*.}" = "json" ]; then
    cp -f "$ftb" "$mask"
    echo "  using prebuilt mask: $ftb"
    python3 - "$mask" <<'PY'
import json, sys
m = json.load(open(sys.argv[1]))
dims = m["dimensions"]
print(f"  {m['total_chunks']:,} chunks / "
      f"{sum(d['region_count'] for d in dims.values())} regions / "
      f"dimension(s) {list(dims)}")
PY
else
    python3 "$here/ftbchunks-reveal.py" "$ftb" --out "$mask" --dimension "$dimension" --verify
fi

echo
echo "== 2/2  pruning the world to those chunks (dry run first) =="
python3 "$here/prune-world-to-reveal.py" "$world" "$mask" "$sp" \
    --dimension "$dimension" --minimal --dry-run
echo
python3 "$here/prune-world-to-reveal.py" "$world" "$mask" "$sp" \
    --dimension "$dimension" --minimal

cat <<EOF

Done. Pruned world: $sp

Now, by hand.

  3. Copy $sp to a machine that can run the pack and open it in SINGLEPLAYER once,
     as a world folder (the directory holding level.dat and region/):

         <game dir>/saves/Stirwick-reveal/

     Open it, open the map (M), let it fill, then quit. Xaero's maps what is in the
     save, and this save holds only the revealed chunks. Do not walk around --
     Minecraft regenerates chunks near the login position and they will show up.

     Where the result lands: look under <game dir>/xaero/world-map/ for a folder that
     is not Multiplayer_*, e.g. World/null/<map>/. Sort by modification time if
     unsure -- those files were just written.

     SANITY CHECK: you should end up with one zip per region in the mask
     ($(python3 -c "import json;print(sum(d['region_count'] for d in json.load(open('$mask'))['dimensions'].values()))") for $player). A handful means it only mapped the spawn area and
     you should use 'Convert All Regions' in the world map settings, or report back.

  4. Clean the HARVEST before anything else -- this is the step that removes terrain
     Minecraft regenerated around the login point. Run it on the harvested folder,
     NOT on the player's own map folder:

       python3 $here/filter-xaero-regions.py \\
           "<game dir>/xaero/world-map/World/null/<map>/" \\
           $mask --dimension $dimension

     Check the list, then re-run with --delete.

  5. Merge the surviving <rx>_<rz>.zip files into the player's existing map folder,
     WITHOUT overwriting anything already there (-n), so any terrain they have
     explored since the swap is kept:

       cp -n <harvested>/*.zip \\
           "<their game dir>/xaero/world-map/Multiplayer_advilplug.top/null/<their map instance>/"

     The right instance is the mw\$... folder there. If the player has not joined the
     server since the swap, have them join once first so Xaero's creates it.

  6. Delete $out -- scratch, usually a few hundred MB.

  Per-dimension: repeat with --dimension <id> and the matching map folder
  (null = overworld, DIM-1 = nether, DIM1 = end).
  Other players: each needs their own local/ftbchunks/data/<uuid>/; there is no
  server-side copy of this data.
EOF