package uboot

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	monov1alpha1 "example.com/monok8s/pkg/apis/monok8s/v1alpha1"
	"example.com/monok8s/pkg/controller/osimage"
	"example.com/monok8s/pkg/node"
)

func ConfigureABBoot(ctx context.Context, nctx *node.NodeContext) error {

	exePath, err := os.Executable()
	if err != nil {
		return fmt.Errorf("get current executable path: %w", err)
	}

	doWrite := false
	writer := NewFWEnvWriter(HostFWEnvCfgPath, exePath)

	bootPart, err := writer.GetEnv(ctx, "boot_part")
	if err != nil {
		if errors.Is(err, ErrEnvNotFound) {

			state, err := osimage.ReadBootState()
			if err != nil {
				return fmt.Errorf("read boot state: %w", err)
			}

			bootPart := state["BOOT_PART"]
			if bootPart == "" {
				return fmt.Errorf("BOOT_PART missing")
			}

			doWrite = true
		} else {
			return fmt.Errorf("get boot_part: %w", err)
		}
	}

	bootSource, err := writer.GetEnv(ctx, "boot_source")
	if err != nil {
		if errors.Is(err, ErrEnvNotFound) {
			target, err := os.Readlink(monov1alpha1.AltPartDeviceLink)
			if err != nil {
				return fmt.Errorf("readlink %q: %w", monov1alpha1.AltPartDeviceLink, err)
			}

			if !filepath.IsAbs(target) {
				target = filepath.Join(filepath.Dir(monov1alpha1.AltPartDeviceLink), target)
			}

			resolved, err := filepath.EvalSymlinks(target)
			if err != nil {
				return fmt.Errorf("resolve %q: %w", target, err)
			}

			base := filepath.Base(resolved)

			if strings.HasPrefix(base, "mmcblk") {
				bootSource = "emmc"
			} else {
				bootSource = "usb"
			}
			doWrite = true
		} else {
			return fmt.Errorf("get boot_source: %w", err)
		}
	}

	if doWrite {
		return writer.EnsureBootEnv(ctx, BootEnvConfig{
			BootSource: bootSource,
			BootPart:   bootPart,
		})
	}

	return nil
}

// This is called by the agent controller/osupgrade/handler.go
func ConfigureNextBoot(ctx context.Context, fwEnvCfgPath string) error {

	exePath, err := os.Executable()
	if err != nil {
		return fmt.Errorf("get current executable path: %w", err)
	}

	writer := NewFWEnvWriter(fwEnvCfgPath, exePath)

	currBootPart, err := writer.GetEnv(ctx, "boot_part")
	if err != nil {
		return fmt.Errorf("get boot_part: %w", err)
	}

	next := "A"
	if currBootPart == "A" {
		next = "B"

	}

	currBootSource, err := writer.GetEnv(ctx, "boot_source")
	if err != nil {
		return fmt.Errorf("get boot_source: %w", err)
	}

	return writer.EnsureBootEnv(ctx, BootEnvConfig{
		BootSource: currBootSource,
		BootPart:   next,
	})
}