package main

// kernel_boot over stand-in roots: a systemd-boot machine with and without the fallback entry, a GRUB machine
// with and without the fallback kernel in its menu, and a machine with neither (novox/hq ADR 0508 §9, issue 1841).

import (
	"os"
	"path/filepath"
	"testing"
)

const selectedVar = "sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f"

func put(t *testing.T, root, p, content string) {
	t.Helper()
	full := filepath.Join(root, p)
	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
		t.Fatal(err)
	}
	write(t, full, content, 0o644)
}

func bootOf(t *testing.T, root string) *BootState {
	t.Helper()
	got, err := (&Machine{Root: root}).Boot()
	if err != nil {
		t.Fatal(err)
	}
	return got
}

func TestKernelBootReadsASystemdBootMachineWithItsFallbackEntry(t *testing.T) {
	root := t.TempDir()
	put(t, root, selectedVar, "\x07\x00\x00\x00a\x00r\x00c\x00h\x00.\x00c\x00o\x00n\x00f\x00\x00\x00")
	put(t, root, "boot/loader/entries/arch.conf", defaultEntry)
	put(t, root, "boot/loader/entries/mesh-linux-lts.conf", "title Arch Linux (linux-lts, fallback)\nlinux /vmlinuz-linux-lts\n")
	put(t, root, "boot/vmlinuz-linux", "k")
	put(t, root, "boot/vmlinuz-linux-lts", "k")
	got := bootOf(t, root)
	if got.Loader != "systemd-boot" || got.Booted != "arch.conf" || !got.FallbackPresent {
		t.Fatalf("%+v", got)
	}
	if len(got.Entries) != 2 || got.Entries[0] != "arch.conf" || got.Entries[1] != "mesh-linux-lts.conf" {
		t.Fatalf("entries: %v", got.Entries)
	}
	if len(got.Kernels) != 2 || got.Kernels[0] != "vmlinuz-linux" || got.Kernels[1] != "vmlinuz-linux-lts" {
		t.Fatalf("kernels: %v", got.Kernels)
	}
	if got.BootFreeKiB <= 0 {
		t.Fatalf("free: %d", got.BootFreeKiB)
	}
}

func TestKernelBootSaysASystemdBootMachineHasNoFallbackYet(t *testing.T) {
	root := t.TempDir()
	put(t, root, selectedVar, "\x07\x00\x00\x00a\x00r\x00c\x00h\x00.\x00c\x00o\x00n\x00f\x00\x00\x00")
	put(t, root, "boot/loader/entries/arch.conf", defaultEntry)
	put(t, root, "boot/vmlinuz-linux", "k")
	// The entry file alone is not the fallback: the kernel it names must be in /boot.
	put(t, root, "boot/loader/entries/mesh-linux-lts.conf", "linux /vmlinuz-linux-lts\n")
	if got := bootOf(t, root); got.FallbackPresent {
		t.Fatalf("a fallback entry without its kernel: %+v", got)
	}
}

func TestKernelBootReadsAGrubMachine(t *testing.T) {
	root := t.TempDir()
	put(t, root, "boot/grub/grub.cfg", grubMenu)
	put(t, root, "boot/vmlinuz-linux", "k")
	put(t, root, "proc/cmdline", bootedCmdline)
	got := bootOf(t, root)
	if got.Loader != "grub" || got.FallbackPresent || got.Booted != "vmlinuz-linux" {
		t.Fatalf("%+v", got)
	}
	if len(got.Entries) != 2 || got.Entries[0] != "Arch Linux" {
		t.Fatalf("entries: %v", got.Entries)
	}
	put(t, root, "boot/vmlinuz-linux-lts", "k")
	put(t, root, "boot/grub/grub.cfg", grubMenu+"menuentry 'Arch Linux LTS' {\n\tlinux\t/boot/vmlinuz-linux-lts root=x rw\n}\n")
	if got := bootOf(t, root); !got.FallbackPresent {
		t.Fatalf("%+v", got)
	}
}

func TestKernelBootSaysWhenThereIsNoLoader(t *testing.T) {
	got := bootOf(t, t.TempDir())
	if got.Loader != "none" || got.FallbackPresent || len(got.Entries) != 0 {
		t.Fatalf("%+v", got)
	}
}