"""ISO generator — squashes rootfs and creates bootable ISO."""

from __future__ import annotations

import subprocess
import tempfile
from pathlib import Path


def generate(rootfs: Path, config: dict, output: Path) -> Path:
    """Generate a bootable ISO from a rootfs."""
    iso_cfg = config.get("iso", {})
    label = iso_cfg.get("label", "EURI")
    name = iso_cfg.get("name", "Euri Linux")
    version = iso_cfg.get("version", "1.0")

    print(f"\n\033[1;36m==>\033[0m \033[1mGenerating ISO: {name} {version}\033[0m")

    workdir = Path(tempfile.mkdtemp(prefix="mklive-iso-"))
    iso_dir = workdir / "iso"
    iso_dir.mkdir()

    # copy rootfs into ISO staging
    _run(["cp", "-a", str(rootfs) + "/.", str(iso_dir)])

    # squashfs
    squash = workdir / "filesystem.squashfs"
    print(f"\033[1;36m==>\033[0m \033[1mCreating squashfs image...\033[0m")
    _run(["mksquashfs", str(iso_dir), str(squash), "-comp", "xz", "-b", "1M"])

    # create ISO layout
    live_dir = iso_dir / "boot" / "x86_64"
    live_dir.mkdir(parents=True, exist_ok=True)
    _run(["cp", str(squash), str(live_dir / "filesystem.squashfs")])

    # EFI boot
    efi_dir = iso_dir / "EFI" / "BOOT"
    efi_dir.mkdir(parents=True, exist_ok=True)
    _run(["cp", "/usr/lib/grub/x86_64-efi/monolithic/grubx64.efi", str(efi_dir / "BOOTX64.EFI")])

    # GRUB config
    grub_cfg = iso_dir / "boot" / "grub" / "grub.cfg"
    grub_cfg.parent.mkdir(parents=True, exist_ok=True)
    grub_cfg.write_text(f"""
set timeout=10
set default=0

menuentry "{name}" {{
    linux /boot/x86_64/vmlinuz boot=live components
    initrd /boot/x86_64/initrd
}}

menuentry "{name} (copy to RAM)" {{
    linux /boot/x86_64/vmlinuz boot=live components toram
    initrd /boot/x86_64/initrd
}}
""")

    # xorriso to create ISO
    iso_path = output / f"{name.lower().replace(' ', '-')}-{version}-x86_64.iso"
    print(f"\033[1;36m==>\033[0m \033[1mCreating ISO: {iso_path.name}\033[0m")
    _run([
        "xorriso", "-as", "mkisofs",
        "-V", label,
        "-o", str(iso_path),
        "-J", "-joliet-long",
        "-b", "boot/x86_64/filesystem.squashfs",
        "-no-emul-boot", "-boot-load-size", "4",
        "-boot-info-table",
        "-eltorito-alt-boot",
        "-e", "boot/x86_64/filesystem.squashfs",
        "-no-emul-boot",
        str(iso_dir),
    ])

    size_mb = iso_path.stat().st_size / (1024 * 1024)
    print(f"\n\033[1;32m==>\033[0m \033[1mISO ready: {iso_path} ({size_mb:.1f} MB)\033[0m")
    return iso_path


def _run(cmd: list[str], **kw) -> subprocess.CompletedProcess:
    print(f"  \033[90m$\033[0m \033[1m{' '.join(cmd)}\033[0m")
    return subprocess.run(cmd, check=True, **kw)