// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

package qemu

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

// Arch abstracts away differences between different architectures.
type Arch string

// Arch constants.
const (
	ArchAmd64 Arch = "amd64"
	ArchArm64 Arch = "arm64"
)

// Valid checks whether the architecture is supported.
func (arch Arch) Valid() bool {
	switch arch {
	case ArchAmd64, ArchArm64:
		return true
	default:
		return false
	}
}

// QemuArch defines which qemu binary to use.
func (arch Arch) QemuArch() string {
	switch arch {
	case ArchAmd64:
		return "x86_64"
	case ArchArm64:
		return "aarch64"
	default:
		panic("unsupported architecture")
	}
}

// QemuMachine defines the machine type for qemu.
func (arch Arch) QemuMachine() string {
	switch arch {
	case ArchAmd64:
		return "q35"
	case ArchArm64:
		return "virt,gic-version=max"
	default:
		panic("unsupported architecture")
	}
}

// Console defines proper argument for the kernel to send logs to serial console.
func (arch Arch) Console() string {
	switch arch {
	case ArchAmd64:
		return "ttyS0"
	case ArchArm64:
		return "ttyAMA0,115200n8"
	default:
		panic("unsupported architecture")
	}
}

// PFlash for UEFI boot.
type PFlash struct {
	Size        int64
	SourcePaths []string
}

// PFlash returns settings for parallel flash.
func (arch Arch) PFlash(uefiEnabled bool, extraUEFISearchPaths []string) []PFlash {
	switch arch {
	case ArchArm64:
		uefiSourcePaths := []string{"/usr/share/qemu-efi-aarch64/QEMU_EFI.fd", "/usr/share/OVMF/QEMU_EFI.fd"}
		for _, p := range extraUEFISearchPaths {
			uefiSourcePaths = append(uefiSourcePaths, filepath.Join(p, "QEMU_EFI.fd"))
		}

		return []PFlash{
			{
				Size:        64 * 1024 * 1024,
				SourcePaths: uefiSourcePaths,
			},
			{
				Size: 64 * 1024 * 1024,
			},
		}
	case ArchAmd64:
		if !uefiEnabled {
			return nil
		}

		uefiSourcePaths := []string{"/usr/share/ovmf/OVMF.fd", "/usr/share/OVMF/OVMF.fd", "/usr/share/OVMF/OVMF_CODE.fd", "/usr/share/OVMF/OVMF_CODE.secboot.fd"}
		for _, p := range extraUEFISearchPaths {
			uefiSourcePaths = append(uefiSourcePaths, filepath.Join(p, "OVMF.fd"))
		}

		return []PFlash{
			{
				Size:        0,
				SourcePaths: uefiSourcePaths,
			},
		}
	default:
		return nil
	}
}

// QemuExecutable returns name of qemu executable for the arch.
func (arch Arch) QemuExecutable() string {
	binaries := []string{
		"qemu-system-" + arch.QemuArch(),
		"qemu-kvm",
		"/usr/libexec/qemu-kvm",
	}

	for _, binary := range binaries {
		if path, err := exec.LookPath(binary); err == nil {
			return path
		}
	}

	return ""
}