package orchestrator

import (
	"os"
	"strconv"
)

// Config holds all tunables for the orchestrator.
type Config struct {
	FCBin      string // path to firecracker binary
	BaseDir    string // working directory for all state
	Kernel     string // path to vmlinux
	Rootfs     string // path to base rootfs.ext4
	VCPUs      int64
	MemMiB     int64
	Bridge     string // host bridge name, or "none" to skip networking
	BridgeCIDR string // e.g. "172.30.0.1/24"
	GuestPrefix string // e.g. "172.30.0" — clones get .10, .11, ...
	GuestGW    string
	BootArgs   string
}

func DefaultConfig() Config {
	c := Config{
		FCBin:       envOr("FC_BIN", "firecracker"),
		BaseDir:     envOr("FC_BASE_DIR", "/tmp/fc-orch"),
		VCPUs:       envOrInt("FC_VCPUS", 1),
		MemMiB:      envOrInt("FC_MEM_MIB", 128),
		Bridge:      envOr("FC_BRIDGE", "fcbr0"),
		BridgeCIDR:  envOr("FC_BRIDGE_CIDR", "172.30.0.1/24"),
		GuestPrefix: envOr("FC_GUEST_PREFIX", "172.30.0"),
		GuestGW:     envOr("FC_GUEST_GW", "172.30.0.1"),
		BootArgs:    "console=ttyS0 reboot=k panic=1 pci=off i8042.noaux quiet loglevel=0",
	}
	c.Kernel = envOr("FC_KERNEL", c.BaseDir+"/vmlinux")
	c.Rootfs = envOr("FC_ROOTFS", c.BaseDir+"/rootfs.ext4")
	return c
}

func envOr(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

func envOrInt(key string, fallback int64) int64 {
	if v := os.Getenv(key); v != "" {
		if n, err := strconv.ParseInt(v, 10, 64); err == nil {
			return n
		}
	}
	return fallback
}