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

BUCKET = "copernicus-dem-30m"
OUTPUT_DIR = "./glo30_world"
LOG_FILE = "download_world.log"

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))

log("Inizio scansione di tutte le cartelle globali...")

folders = []

paginator = s3.get_paginator("list_objects_v2")

# Legge SOLO le directory top-level
for page in paginator.paginate(Bucket=BUCKET, Delimiter="/"):
    for prefix in page.get("CommonPrefixes", []):
        folder = prefix["Prefix"]

        # Filtra solo i tile DEM
        if folder.startswith("Copernicus_DSM_COG_10_") and 
folder.endswith("_DEM/"):
            folders.append(folder)
            log(f"[FOUND] {folder}")

log(f"Trovate {len(folders)} cartelle globali")

# -----------------------------
# DOWNLOAD SOLO IL DEM PRINCIPALE
# -----------------------------
for folder in folders:
    tif_name = folder[:-1] + ".tif"  # rimuove "/" e aggiunge .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.")