#!/usr/bin/env -S bash -eo pipefail
#
# Project Titanoboa
#
# Description: Create bootable ISOs from bootc container images.

# Container-native ISO contract v0.1.0
# See https://github.com/ondrejbudai/bootc-isos/tree/main
#
# This spec is inspired by the layout of Fedora bootc images and Fedora live ISO images.
#
# - The kernel is expected to be in /usr/lib/module/*/vmlinuz. If there are multiple kernels, the behavior is unspecified. This is to be specified in a future version of this contract. The kernel is put in /images/pxeboot/vmlinuz in the ISO.
# - The initramfs is expected to be next to the kernel with the filename initramfs.img. The initramfs is put in /images/pxeboot/initrd.img.
# - The UEFI vendor is specified by a directory name in /usr/lib/efi/shim/*/EFI/$VENDOR. If there are multiple directories, the behaviour is unspecified. The BOOT directory is always ignored.
# - Shim and grub2 EFI binaries (shimx64.efi, mmx64.efi, gcdx64.efi) are expected to be in /boot/efi/EFI/$VENDOR.
# - GRUB2 modules are expected to be in /usr/lib/grub/i386-pc.
# - Required executables are podman, mksquashfs, xorriso, implantisomd5, grub2-mkimage, and python.
# - The container image is converted to a squashfs archive and put into /LiveOS/squashfs.img in the ISO.
# - Additional configuration can be written into /usr/lib/bootc-image-builder/iso.yaml in YAML format. The file currently supports 2 top-level keys:
#   - label (string): Label of the ISO
#   - grub2 (object): GRUB2 configuration, supports the following keys:
#     - default (string): Default menu item
#     - timeout (string): Default timeout (in seconds)
#     - entries (array of objects): GRUB2 menu entries with the following keys (all are required):
#       - name (string): Name of the entry
#       - linux (string): Path to the kernel + kernel arguments (the path is always /images/pxeboot/vmlinuz in this version of this spec)
#       - initrd (string): Path to the initramfs (the path is always /images/pxeboot/initrd.img in this version of this spec)
# - The --bootc-installer-payload-ref argument to image-builder can optionally be used to copy a container image from the host's container storage to /var/lib/containers/storage in the squashfs archive.

{
    # Image to be injected on the iso as squashfs. Example: localhost/live_env:latest
    TITANOBOA_CTR_IMAGE=${1:-${TITANOBOA_CTR_IMAGE}}

    # Directory where the ISO will be stored
    TITANOBOA_OUTPUT_DIR=${TITANOBOA_OUTPUT_DIR:-./output}

    # Whenever Titanoboa is running inside a container
    TITANOBOA_INSIDE_CONTAINER=${TITANOBOA_INSIDE_CONTAINER:-false}

    SCRIPT_DIR=$(dirname "$0")

    mkdir -p "$TITANOBOA_OUTPUT_DIR"

    # If we are running inside a container
    if [ "$TITANOBOA_INSIDE_CONTAINER" = "true" ]; then
        TITANOBOA_OUTPUT_DIR=/output
        if ! mountpoint -q "$TITANOBOA_OUTPUT_DIR"; then
            echo "Error: output directory must be a volume mountpoint"
            exit 1
        fi
        if ! mountpoint -q /usr/lib/containers/storage; then
            echo "Error: /usr/lib/containers/storage must be a volume mountpoint"
            exit 1
        fi
        if ! mountpoint -q /rootfs; then
            echo "Error: /rootfs must be a volume mountpoint"
            exit 1
        fi
        /app/bin/build_iso.sh
    else

        if [ -z "$TITANOBOA_CTR_IMAGE" ]; then
            echo "Error: container image in param 1 nor TITANOBOA_CTR_IMAGE environment variable"
            exit 1
        fi

        sudo podman run --rm -i \
            --cap-add sys_admin --security-opt label=disable \
            -v "$SCRIPT_DIR"/build_iso.sh:/src/build_iso.sh:ro \
            --mount type=image,source="$TITANOBOA_CTR_IMAGE",dst=/rootfs \
            -v "$TITANOBOA_OUTPUT_DIR":/output \
            quay.io/fedora/fedora:latest /src/build_iso.sh
    fi
} >&2

realpath "$TITANOBOA_OUTPUT_DIR"/*.iso | head -1