# KubeSolo OS — GRUB Configuration
# A/B partition boot with automatic rollback
#
# Partition layout:
#   (hd0,gpt1) — EFI/Boot  (256 MB, FAT32) — contains GRUB + grubenv
#   (hd0,gpt2) — System A  (512 MB, ext4)  — vmlinuz + kubesolo-os.gz
#   (hd0,gpt3) — System B  (512 MB, ext4)  — vmlinuz + kubesolo-os.gz
#   (hd0,gpt4) — Data      (remaining, ext4) — persistent K8s state
#
# Environment variables (in grubenv):
#   active_slot   — "A" or "B" (which partition to boot)
#   boot_counter  — 3→2→1→0 (decremented on each failed boot)
#   boot_success  — 0 or 1 (set to 1 by health check post-boot)

set default=0
set timeout=3

# Load saved environment
load_env

# --- A/B Rollback Logic ---
# On every boot, check if the last boot was successful.
# If not, decrement the counter. If counter hits 0, swap slots.

if [ "${boot_success}" != "1" ]; then
    # Last boot failed — check counter
    if [ "${boot_counter}" = "0" ]; then
        # Counter exhausted — rollback to other slot
        if [ "${active_slot}" = "A" ]; then
            set active_slot=B
        else
            set active_slot=A
        fi
        save_env active_slot
        set boot_counter=3
        save_env boot_counter
    else
        # Decrement counter (GRUB doesn't have arithmetic)
        if [ "${boot_counter}" = "3" ]; then
            set boot_counter=2
        elif [ "${boot_counter}" = "2" ]; then
            set boot_counter=1
        elif [ "${boot_counter}" = "1" ]; then
            set boot_counter=0
        fi
        save_env boot_counter
    fi
fi

# Reset boot_success for this boot attempt — health check must set it to 1
set boot_success=0
save_env boot_success

# --- Resolve boot partition ---
if [ "${active_slot}" = "A" ]; then
    set root='(hd0,gpt2)'
    set slot_label="System A"
else
    set root='(hd0,gpt3)'
    set slot_label="System B"
fi

# --- Menu Entries ---

menuentry "KubeSolo OS (${slot_label})" {
    echo "Booting KubeSolo OS from ${slot_label}..."
    echo "Boot counter: ${boot_counter}, Boot success: ${boot_success}"
    linux /vmlinuz kubesolo.data=LABEL=KSOLODATA quiet
    initrd /kubesolo-os.gz
}

menuentry "KubeSolo OS (${slot_label}) — Debug Mode" {
    echo "Booting KubeSolo OS (debug) from ${slot_label}..."
    linux /vmlinuz kubesolo.data=LABEL=KSOLODATA kubesolo.debug console=ttyS0,115200n8
    initrd /kubesolo-os.gz
}

menuentry "KubeSolo OS — Emergency Shell" {
    echo "Booting to emergency shell..."
    linux /vmlinuz kubesolo.shell console=ttyS0,115200n8
    initrd /kubesolo-os.gz
}

menuentry "KubeSolo OS — Boot Other Slot" {
    # Manually boot the passive slot (for testing)
    if [ "${active_slot}" = "A" ]; then
        set root='(hd0,gpt3)'
        echo "Booting from System B (passive)..."
    else
        set root='(hd0,gpt2)'
        echo "Booting from System A (passive)..."
    fi
    linux /vmlinuz kubesolo.data=LABEL=KSOLODATA kubesolo.debug console=ttyS0,115200n8
    initrd /kubesolo-os.gz
}