#!/usr/bin/env python3
import sqlite3
import json
import subprocess
import sys
from pathlib import Path

def read_gdal_bounds(raster):
    """Legge i bounds WGS84 dal TIFF usando gdalinfo -json."""
    info = subprocess.check_output(["gdalinfo", "-json", raster])
    info = json.loads(info)

    if "wgs84Extent" in info:
        coords = info["wgs84Extent"]["coordinates"][0]
        minlon, minlat = coords[0]
        maxlon, maxlat = coords[2]
    else:
        cc = info["cornerCoordinates"]
        minlon, minlat = cc["lowerLeft"]
        maxlon, maxlat = cc["upperRight"]

    # Normalizzazione latitudine
    if minlat > maxlat:
        minlat, maxlat = maxlat, minlat

    return (minlon, minlat, maxlon, maxlat)


def read_mbtiles(mbtiles):
    """Legge tile info e metadata da un MBTiles."""
    conn = sqlite3.connect(mbtiles)
    cur = conn.cursor()

    # Verifica tabella tiles
    cur.execute("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='tiles';")
    if cur.fetchone()[0] == 0:
        raise RuntimeError("La tabella 'tiles' non esiste nell'MBTiles.")

    # Conta tile
    cur.execute("SELECT COUNT(*) FROM tiles;")
    tile_count = cur.fetchone()[0]
    if tile_count == 0:
        raise RuntimeError("La tabella 'tiles' è vuota.")

    # Zoom min/max
    cur.execute("SELECT MIN(zoom_level), MAX(zoom_level) FROM tiles;")
    minzoom, maxzoom = cur.fetchone()

    # Metadata
    cur.execute("CREATE TABLE IF NOT EXISTS metadata (name TEXT PRIMARY KEY, value TEXT);")
    cur.execute("SELECT name, value FROM metadata;")
    metadata = dict(cur.fetchall())

    return conn, cur, tile_count, minzoom, maxzoom, metadata


def write_metadata(cur, name, value):
    cur.execute("REPLACE INTO metadata (name, value) VALUES (?, ?)", (name, value))


def main():
    if len(sys.argv) != 3:
        print("Uso: python3 verify_and_fix_mbtiles.py <raster.tif> <file.mbtiles>")
        sys.exit(1)

    raster = Path(sys.argv[1])
    mbtiles = Path(sys.argv[2])

    if not raster.exists():
        print(f"Raster non trovato: {raster}")
        sys.exit(1)
    if not mbtiles.exists():
        print(f"MBTiles non trovato: {mbtiles}")
        sys.exit(1)

    print("== Verifica e correzione metadata MBTiles ==")

    # 1) Bounds dal TIFF
    minlon, minlat, maxlon, maxlat = read_gdal_bounds(raster)
    expected_bounds = f"{minlon:.6f},{minlat:.6f},{maxlon:.6f},{maxlat:.6f}"
    print(f"Bounds TIFF: {expected_bounds}")

    # 2) Lettura MBTiles
    conn, cur, tile_count, minzoom, maxzoom, metadata = read_mbtiles(mbtiles)

    print(f"Tile count: {tile_count}")
    print(f"Zoom effettivi: {minzoom}..{maxzoom}")

    # 3) Verifica/correzione bounds
    mb_bounds = metadata.get("bounds")
    if mb_bounds != expected_bounds:
        print(f"✘ Bounds NON corretti → FIX")
        write_metadata(cur, "bounds", expected_bounds)
    else:
        print("✔ Bounds OK")

    # 4) Verifica/correzione minzoom/maxzoom
    mz = int(metadata.get("minzoom", -1))
    xz = int(metadata.get("maxzoom", -1))

    if mz != minzoom or xz != maxzoom:
        print(f"✘ minzoom/maxzoom NON coerenti → FIX")
        write_metadata(cur, "minzoom", str(minzoom))
        write_metadata(cur, "maxzoom", str(maxzoom))
    else:
        print("✔ minzoom/maxzoom OK")

    # 5) Verifica/correzione center
    ctr_lon = (minlon + maxlon) / 2
    ctr_lat = (minlat + maxlat) / 2
    ctr_zoom = (minzoom + maxzoom) // 2
    expected_center = f"{ctr_lon:.6f},{ctr_lat:.6f},{ctr_zoom}"

    if metadata.get("center") != expected_center:
        print(f"✘ Center NON corretto → FIX")
        write_metadata(cur, "center", expected_center)
    else:
        print("✔ Center OK")

    # 6) Verifica/correzione format
    if metadata.get("format") != "png":
        print("✘ Format NON corretto → FIX")
        write_metadata(cur, "format", "png")
    else:
        print("✔ Format OK")

    # 7) Verifica/correzione scheme
    if metadata.get("scheme") != "xyz":
        print("✘ Scheme NON corretto → FIX")
        write_metadata(cur, "scheme", "xyz")
    else:
        print("✔ Scheme OK")

    # 8) Commit
    conn.commit()
    conn.close()

    print("\n== Correzione completata ==")
    print("MBTiles ora ha metadata coerenti e validi.")


if __name__ == "__main__":
    main()