#!/usr/bin/env python3
"""Transfer dashcam MP4 files from SD card to USB-SSD with date/camera structure."""

import fcntl
import logging
import os
import re
import shutil
import sys

SD_CARD = "/mnt/sdcard"
SOURCE_DIR = os.path.join(SD_CARD, "Novatek", "Movie")
SSD = "/mnt/ultratouch"
TARGET_BASE = os.path.join(SSD, "dashcam")
LOG_FILE = "/var/log/dashcam-transfer.log"
LOCK_FILE = "/var/run/dashcam-transfer.lock"

CAMERA_MAP = {"F": "front", "B": "back"}
FILE_PATTERN = re.compile(r"^(\d{8})\d{6}_\d+([FB])\.MP4$")


def setup_logging():
    logging.basicConfig(
        filename=LOG_FILE,
        level=logging.INFO,
        format="[%(asctime)s] %(levelname)s %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
    )


def acquire_lock():
    lock_fd = open(LOCK_FILE, "w")
    try:
        fcntl.flock(lock_fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
    except IOError:
        logging.warning("Lockfile actief — script al bezig")
        sys.exit(1)
    return lock_fd


def check_mount(path, name):
    if not os.path.ismount(path):
        logging.error("%s niet gemount: %s", name, path)
        sys.exit(1)


def get_mp4_files(src_dir):
    if not os.path.isdir(src_dir):
        return []
    result = []
    for fname in os.listdir(src_dir):
        match = FILE_PATTERN.match(fname)
        if match:
            result.append((fname, match.group(1), match.group(2).upper()))
    return result


def ensure_free_space(needed_bytes, target_base):
    stat = os.statvfs(target_base)
    free = stat.f_frsize * stat.f_bavail
    if free >= needed_bytes:
        return

    logging.warning(
        "Onvoldoende ruimte: %d bytes nodig, %d bytes vrij", needed_bytes, free
    )

    date_dirs = sorted(
        d
        for d in os.listdir(target_base)
        if re.match(r"^\d{8}$", d)
        and os.path.isdir(os.path.join(target_base, d))
    )

    freed = 0
    removed = []
    for date_name in date_dirs:
        if free + freed >= needed_bytes:
            break
        dir_path = os.path.join(target_base, date_name)
        dir_size = sum(
            os.path.getsize(os.path.join(dirpath, f))
            for dirpath, _, filenames in os.walk(dir_path)
            for f in filenames
        )
        shutil.rmtree(dir_path)
        freed += dir_size
        removed.append(date_name)
        logging.info("Ruimte gemaakt: %s verwijderd (%d bytes)", date_name, dir_size)

    if free + freed < needed_bytes:
        logging.error(
            "Nog steeds onvoldoende ruimte na verwijderen %d mappen: "
            "%d bytes nodig, %d bytes vrij",
            len(removed),
            needed_bytes,
            free + freed,
        )
        sys.exit(1)

    logging.info("Ruimte vrijgemaakt: %d bytes door %d mappen", freed, len(removed))


def main():
    setup_logging()
    lock_fd = acquire_lock()

    check_mount(SD_CARD, "SD-kaart")
    check_mount(SSD, "Ultratouch SSD")

    files = get_mp4_files(SOURCE_DIR)
    if not files:
        logging.info("Geen MP4 bestanden gevonden in %s", SOURCE_DIR)
        return

    total_size = sum(
        os.path.getsize(os.path.join(SOURCE_DIR, fname)) for fname, _, _ in files
    )
    logging.info(
        "Start transfer: %d bestanden, %d bytes", len(files), total_size
    )

    ensure_free_space(total_size, TARGET_BASE)

    ok = 0
    errors = 0
    for fname, date_str, cam in files:
        target_dir = os.path.join(TARGET_BASE, date_str, CAMERA_MAP[cam])
        os.makedirs(target_dir, exist_ok=True)
        src = os.path.join(SOURCE_DIR, fname)
        dst = os.path.join(target_dir, fname)
        try:
            shutil.move(src, dst)
            logging.info(
                "Verplaatst: %s → %s/%s/", fname, date_str, CAMERA_MAP[cam]
            )
            ok += 1
        except OSError as e:
            logging.error("Fout bij verplaatsen %s: %s", fname, e)
            errors += 1

    logging.info(
        "Transfer voltooid: %d ok, %d fouten, %d bytes", ok, errors, total_size
    )


if __name__ == "__main__":
    main()