"""Generate fstab and crypttab configuration files."""

from pathlib import Path

from .utils import info, success, run_quiet
from .disk import DiskLayout, DiskConfig


def get_uuid(device: Path) -> str:
    """Get UUID of a block device."""
    result = run_quiet("blkid", "-s", "UUID", "-o", "value", str(device))
    return result.stdout.strip()


def get_luks_uuid(device: Path) -> str:
    """Get UUID of a LUKS container."""
    return get_uuid(device)


def generate_fstab(
    layout: DiskLayout,
    config: DiskConfig,
    mount_root: Path | None = None,
) -> None:
    """Generate /etc/fstab for the new system."""
    if mount_root is None:
        mount_root = config.mount_root

    info("Generating /etc/fstab...")

    efi_uuid = get_uuid(layout.part_efi)
    mapper = config.mapper_path
    opts = config.btrfs_opts

    fstab_content = f"""\
# /etc/fstab - Generated by install-installer v4
# Legion S7 with LUKS encryption + Btrfs subvolumes

# EFI System Partition
UUID={efi_uuid}  /boot  vfat  noatime,defaults  0 2

# Encrypted swap - NOTE: This entry is NOT used by swapon directly.
# Swap activation is handled by the OpenRC dmcrypt service (/etc/conf.d/dmcrypt)
# which creates /dev/mapper/swap with a random key at boot.
{layout.part_swap}  none  swap  sw,cipher=aes-xts-plain64,size=256  0 0

# Btrfs on LUKS ({config.mapper_name})
{mapper}  /            btrfs  {opts},subvol=@           0 0
{mapper}  /home        btrfs  {opts},subvol=@home       0 0
{mapper}  /var         btrfs  {opts},subvol=@var        0 0
{mapper}  /var/log     btrfs  {opts},subvol=@log        0 0
{mapper}  /.snapshots  btrfs  {opts},subvol=@snapshots  0 0
"""

    fstab_path = mount_root / "etc/fstab"
    fstab_path.write_text(fstab_content)

    success(f"Generated {fstab_path}")


def generate_crypttab(
    layout: DiskLayout,
    config: DiskConfig,
    mount_root: Path | None = None,
) -> None:
    """Generate /etc/crypttab for the new system."""
    if mount_root is None:
        mount_root = config.mount_root

    info("Generating /etc/crypttab...")

    luks_uuid = get_luks_uuid(layout.part_root)

    crypttab_content = f"""\
# /etc/crypttab - Generated by install-installer v4
# LUKS root partition

{config.mapper_name}  UUID={luks_uuid}  none  luks
"""

    crypttab_path = mount_root / "etc/crypttab"
    crypttab_path.write_text(crypttab_content)

    success(f"Generated {crypttab_path}")


def generate_dmcrypt_conf(
    layout: DiskLayout,
    mount_root: Path | None = None,
) -> None:
    """Generate /etc/conf.d/dmcrypt for OpenRC encrypted swap."""
    if mount_root is None:
        mount_root = Path("/mnt/gentoo")

    info("Generating /etc/conf.d/dmcrypt...")

    dmcrypt_content = f"""\
# /etc/conf.d/dmcrypt - Generated by install-installer v4
# Encrypted swap with random key (no hibernate support)

swap=swap
source='{layout.part_swap}'
"""

    dmcrypt_path = mount_root / "etc/conf.d/dmcrypt"
    dmcrypt_path.parent.mkdir(parents=True, exist_ok=True)
    dmcrypt_path.write_text(dmcrypt_content)

    success(f"Generated {dmcrypt_path}")


def generate_all(
    layout: DiskLayout,
    config: DiskConfig,
    mount_root: Path | None = None,
) -> None:
    """Generate all filesystem configuration files."""
    if mount_root is None:
        mount_root = config.mount_root

    generate_fstab(layout, config, mount_root)
    generate_crypttab(layout, config, mount_root)
    generate_dmcrypt_conf(layout, mount_root)

    print()
    success("=== Filesystem configuration complete ===")