import boto3
import os
import logging
from botocore import UNSIGNED
from botocore.config import Config

BUCKET = "copernicus-dem-30m"
OUTPUT_DIR = "./glo30_europe"
LOG_FILE = "download_europe.log"

# Europa approx:
lat_range = range(34, 73)   # N34–N72
lon_east  = range(0, 46)    # E000–E045
lon_west  = range(1, 26)    # W001–W025

logging.basicConfig(
    filename=LOG_FILE,
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s",
)

console = logging.getLogger("console")
console.setLevel(logging.INFO)
console.addHandler(logging.StreamHandler())

def log(msg):
    logging.info(msg)
    console.info(msg)

os.makedirs(OUTPUT_DIR, exist_ok=True)

s3 = boto3.client("s3", config=Config(signature_version=UNSIGNED))

def folder_name(lat, lon, east=True):
    if east:
        return f"Copernicus_DSM_COG_10_N{lat:02d}_00_E{lon:03d}_00_DEM/"
    else:
        return f"Copernicus_DSM_COG_10_N{lat:02d}_00_W{lon:03d}_00_DEM/"

log("Inizio scansione directory europee...")

found_folders = []

paginator = s3.get_paginator("list_objects_v2")

for page in paginator.paginate(Bucket=BUCKET, Delimiter="/"):
    for prefix in page.get("CommonPrefixes", []):
        folder = prefix["Prefix"]

        # EASTERN EUROPE
        for lat in lat_range:
            for lon in lon_east:
                if folder == folder_name(lat, lon, east=True):
                    found_folders.append(folder)
                    log(f"[FOUND] {folder}")

        # WESTERN EUROPE (longitudes W)
        for lat in lat_range:
            for lon in lon_west:
                if folder == folder_name(lat, lon, east=False):
                    found_folders.append(folder)
                    log(f"[FOUND] {folder}")

log(f"Trovate {len(found_folders)} cartelle europee")

# -----------------------------
# DOWNLOAD DEM PRINCIPALE
# -----------------------------
for folder in found_folders:
    tif_name = folder[:-1] + ".tif"
    key = folder + tif_name.split("/")[-1]
    out_path = os.path.join(OUTPUT_DIR, tif_name.split("/")[-1])

    if os.path.exists(out_path):
        log(f"[SKIP] {out_path} già presente")
        continue

    log(f"[DOWNLOAD] {key}")
    try:
        s3.download_file(BUCKET, key, out_path)
        log(f"[OK] {key} scaricato")
    except Exception as e:
        log(f"[ERROR] {key} → {e}")

log("Completato.")