#!/bin/zsh

SRC_ROOT="tiles_italy_new"
DST_ROOT="merged_tiles"

mkdir -p "$DST_ROOT"

echo "[INFO] Merge tiles da $SRC_ROOT → $DST_ROOT"

# Scorri tutte le tile z/x/y.png in tutte le sottocartelle
find "$SRC_ROOT" -type f -name '*.png' | while read -r TILE; do
    # TILE = tiles_italy_new/<DEM>/<z>/<x>/<y>.png
    REL="${TILE#$SRC_ROOT/}"          # <DEM>/<z>/<x>/<y>.png
    DEM="${REL%%/*}"                  # <DEM>
    REST="${REL#*/}"                  # <z>/<x>/<y>.png

    Z="$(echo "$REST" | cut -d'/' -f1)"
    X="$(echo "$REST" | cut -d'/' -f2)"
    Y_FILE="$(echo "$REST" | cut -d'/' -f3)"

    OUT_DIR="$DST_ROOT/$Z/$X"
    OUT_PATH="$OUT_DIR/$Y_FILE"

    mkdir -p "$OUT_DIR"

    if [ -f "$OUT_PATH" ]; then
        echo "[WARN] Tile già esistente, lascio la prima: 
$OUT_PATH"
        continue
    fi

    cp "$TILE" "$OUT_PATH"
done

echo "[INFO] Merge completato in $DST_ROOT"