$extens("include.py")
include("import os", [])

def csv_report(path: str = "~/extella-demo-data/orders.csv", group_by: str = "region", value: str = "amount", top: int = 5, filter_column: str = "", filter_value: str = "") -> dict:
    # A report over a CSV file that lives on the device this program runs on.
    # Groups the rows by one column, sums a numeric column, returns the top groups.
    import csv, hashlib, os, platform, socket, time
    started = time.time()
    full = os.path.expanduser(path)
    if not os.path.isfile(full):
        return {"status": "error", "reason": "no such file on this device: " + path}
    raw = open(full, "rb").read()
    rows = list(csv.DictReader(raw.decode("utf-8", "replace").splitlines()))
    columns = list(rows[0].keys()) if rows else []
    for name in (group_by, value):
        if name not in columns:
            return {"status": "error", "reason": "no column " + str(name) + " in the file", "columns": columns}
    if filter_column and filter_column not in columns:
        return {"status": "error", "reason": "no column " + str(filter_column) + " in the file", "columns": columns}
    totals, counts, used, skipped = {}, {}, 0, 0
    for row in rows:
        if filter_column and not str(row.get(filter_column, "")).startswith(str(filter_value)):
            continue
        try:
            number = float(row[value])
        except (TypeError, ValueError):
            skipped += 1
            continue
        key = row[group_by]
        totals[key] = totals.get(key, 0.0) + number
        counts[key] = counts.get(key, 0) + 1
        used += 1
    grand = sum(totals.values())
    limit = max(1, min(int(top), 50))
    ordered = sorted(totals.items(), key=lambda item: -item[1])[:limit]
    table = [{"group": key, "total": round(total, 2), "rows": counts[key], "share": round(100.0 * total / grand, 1) if grand else 0.0} for key, total in ordered]
    return {"status": "success", "table": table, "group_by": group_by, "value": value, "filter": (filter_column + "=" + str(filter_value) + "*") if filter_column else "",
            "rows_in_file": len(rows), "rows_used": used, "rows_skipped": skipped, "groups": len(totals), "grand_total": round(grand, 2),
            "file": path, "file_sha256": hashlib.sha256(raw).hexdigest(), "host": socket.gethostname(), "os": platform.system() + " " + platform.machine(),
            "seconds_on_device": round(time.time() - started, 3)}