package main

import (
	"fmt"
	"log"
	"os"
	"os/exec"

	"go.i3wm.org/i3"
	"gopkg.in/yaml.v3"
)

type Config struct {
	Default    string            `yaml:"default"`
	Workspaces map[string]string `yaml:"workspaces"`
}

func getWallpaper(workspace string, config Config) string {
	file := config.Default
	workspaceFile := config.Workspaces[workspace]

	if workspaceFile != "" {
		file = workspaceFile
	}

	return file
}

func main() {
	recv := i3.Subscribe(i3.WorkspaceEventType)

	if len(os.Args) != 2 {
		fmt.Errorf("Configuration required!")
		os.Exit(1)
	}

	data, err := os.ReadFile(os.Args[1])
	config := Config{}

	if err != nil {
		log.Printf("[error] %s", err.Error())
	}

	err = yaml.Unmarshal(data, &config)

	if err != nil {
		log.Printf("[error] %s", err.Error())
	}

	for recv.Next() {
		event := recv.Event().(*i3.WorkspaceEvent)

		if event.Change != "focus" {
			continue
		}

		outputs, err := i3.GetOutputs()
		args := []string{}

		if err == nil {
			for _, output := range outputs {
				if output.CurrentWorkspace != "" {
					args = append(args, "--bg-fill", getWallpaper(output.CurrentWorkspace, config))
				}
			}

			cmd := exec.Command("feh", args...)
			cmd.Env = os.Environ()
			log.Printf("[UPDATE] %s", cmd.String())

			if err := cmd.Run(); err != nil {
				log.Printf("[ERROR] %s", err.Error())
			}
		} else {
			log.Printf("[ERROR] %s", err.Error())
		}
	}
}