#!/usr/bin/env bash
set -euo pipefail

# --------------------------------------------------------------------
# Imposta metadati essenziali in un file .mbtiles (schema XYZ)
#  - Calcola bounds (ovest,sud,est,nord) dal raster sorgente (GeoTIFF/COG)
#  - Calcola center (lon,lat,zoom)
#  - Legge min/max zoom dalla tabella 'tiles' e li scrive nella 'metadata'
#  - Imposta name/format/type/attribution
#
# Requisiti: gdalinfo (GDAL), jq, sqlite3
# --------------------------------------------------------------------
# USO:
#   ./mbtiles_set_metadata.sh \
#       --mbtiles aa.mbtiles \
#       --raster aa_rgb.tif \
#       [--name "Terrain RGB Adamello"] \
#       [--type overlay|baselayer] \
#       [--format png|jpg] \
#       [--zoom <Zcenter>] \
#       [--attribution " Copernicus DEM (GLO-30), ESA"]
#
# NOTE:
# - 'bounds' e 'center' sono calcolati in EPSG:4326 (lon/lat).
# - Se il raster non riassume esattamente lestensione delle tile,
#   passa un raster "clip" coerente con larea tilata.
# - Lo script usa REPLACE INTO per compatibilit con SQLite < 3.24.
# --------------------------------------------------------------------

# ---------- parsing argomenti ----------
MBTILES=""
RASTER=""
LAYER_NAME=""
LAYER_TYPE="overlay"
FORMAT="png"
CENTER_Z=""
ATTRIBUTION=""

while [[ $# -gt 0 ]]; do
  case "$1" in
    --mbtiles)     MBTILES="$2"; shift 2;;
    --raster)      RASTER="$2"; shift 2;;
    --name)        LAYER_NAME="$2"; shift 2;;
    --type)        LAYER_TYPE="$2"; shift 2;;
    --format)      FORMAT="$2"; shift 2;;
    --zoom)        CENTER_Z="$2"; shift 2;;
    --attribution) ATTRIBUTION="$2"; shift 2;;
    -h|--help)
      sed -n '1,80p' "$0"; exit 0;;
    *)
      echo "Argomento sconosciuto: $1" >&2; exit 1;;
  esac
done

if [[ -z "$MBTILES" || -z "$RASTER" ]]; then
  echo "Uso: $0 --mbtiles <file.mbtiles> --raster <raster.tif> [opzioni]" >&2
  exit 1
fi

if [[ ! -f "$MBTILES" ]]; then
  echo "File MBTiles non trovato: $MBTILES" >&2; exit 1
fi
if [[ ! -f "$RASTER" ]]; then
  echo "Raster non trovato: $RASTER" >&2; exit 1
fi

command -v gdalinfo >/dev/null || { echo "gdalinfo non trovato"; exit 1; }
command -v jq       >/dev/null || { echo "jq non trovato";       exit 1; }
command -v sqlite3  >/dev/null || { echo "sqlite3 non trovato";  exit 1; }

# ---------- step 1: calcolo bounds dal raster (EPSG:4326) ----------
# Usiamo wgs84Extent se presente, altrimenti cornerCoordinates.
# gdalinfo -json fornisce geometrie e corner coords in lon/lat.
export LC_ALL=C
export LANG=C

GDAL_JSON="$(gdalinfo -json "$RASTER")"

has_wgs84=$(echo "$GDAL_JSON" | jq 'has("wgs84Extent")')
if [[ "$has_wgs84" == "true" ]]; then
  # Polygon ring: [ [minLon,minLat], [maxLon,minLat], [maxLon,maxLat], [minLon,maxLat], ... ]
  read -r MINLON MINLAT MAXLON MAXLAT <<<"$(echo "$GDAL_JSON" \
    | jq -r '.wgs84Extent.coordinates[0] |
              [.[0][0], .[0][1], .[2][0], .[2][1]] | @tsv')"
else
  # cornerCoordinates: upperLeft, lowerLeft, upperRight, lowerRight (lon,lat)
  read -r MINLON MINLAT MAXLON MAXLAT <<<"$(echo "$GDAL_JSON" \
    | jq -r '.cornerCoordinates as $c |
             [$c.lowerLeft[0], $c.lowerLeft[1], $c.upperRight[0], $c.upperRight[1]] | @tsv')"
fi

# Arrotonda a 6 decimali per compattare la stringa
printf -v BOUNDS "%.6f,%.6f,%.6f,%.6f" "$MINLON" "$MINLAT" "$MAXLON" "$MAXLAT"

# ---------- step 2: calcolo center (lon,lat,zoom) ----------
# lon,lat = met dei bounds; zoom: se non fornito, media tra min e max zoom presenti nelle tile
CTR_LON=$(awk -v a="$MINLON" -v b="$MAXLON" 'BEGIN{printf "%.6f",(a+b)/2.0}')
CTR_LAT=$(awk -v a="$MINLAT" -v b="$MAXLAT" 'BEGIN{printf "%.6f",(a+b)/2.0}')

# Leggi min/max zoom dalla tabella 'tiles'
read -r TMIN TMAX <<<"$(sqlite3 "$MBTILES" "SELECT MIN(zoom_level), MAX(zoom_level) FROM tiles;")"
if [[ -z "$TMIN" || -z "$TMAX" ]]; then
  echo "Attenzione: tabella 'tiles' vuota o mancante in $MBTILES" >&2
  TMIN=0; TMAX=0
fi

if [[ -z "${CENTER_Z}" ]]; then
  CENTER_Z=$(( (TMIN + TMAX) / 2 ))
fi

CENTER="${CTR_LON},${CTR_LAT},${CENTER_Z}"

# ---------- step 3: definisci name/format/type/attribution ----------
if [[ -z "$LAYER_NAME" ]]; then
  # Usa il nome file come default
  base="$(basename "$MBTILES")"
  LAYER_NAME="${base%.*}"
fi

# ---------- step 4: crea tabella metadata (se non esiste) e scrivi i metadati ----------
sqlite3 "$MBTILES" <<SQL
CREATE TABLE IF NOT EXISTS metadata (name TEXT PRIMARY KEY, value TEXT);
REPLACE INTO metadata(name,value) VALUES('name',      '$LAYER_NAME');
REPLACE INTO metadata(name,value) VALUES('format',    '$FORMAT');
REPLACE INTO metadata(name,value) VALUES('type',      '$LAYER_TYPE');
REPLACE INTO metadata(name,value) VALUES('minzoom',   '$TMIN');
REPLACE INTO metadata(name,value) VALUES('maxzoom',   '$TMAX');
REPLACE INTO metadata(name,value) VALUES('bounds',    '$BOUNDS');
REPLACE INTO metadata(name,value) VALUES('center',    '$CENTER');
$( [[ -n "$ATTRIBUTION" ]] && echo "REPLACE INTO metadata(name,value) VALUES('attribution','$ATTRIBUTION');" )
SQL

# ---------- step 5: stampa riepilogo ----------
echo "==> METADATA scritti in: $MBTILES"
sqlite3 "$MBTILES" "SELECT name,value FROM metadata ORDER BY name;"
echo
echo "Zoom effettivi nelle tile: $(sqlite3 "$MBTILES" "SELECT MIN(zoom_level)||'..'||MAX(zoom_level) FROM tiles;")"
echo "Bounds: $BOUNDS"
echo "Center: $CENTER"