rpcfetch/fetch/config.go

package main

import (
	"encoding/gob"
	"fmt"
	"log"
	"os"
	"path"
	"sync"
	"sync/atomic"

	"git.ophivana.moe/cat/rpcfetch"
	"github.com/google/uuid"
)

var (
	conf     *config
	confLock = &sync.RWMutex{}

	defaultUUID = uuid.MustParse("7ec9eb89-5472-4392-a59b-531d7f8df442")
)

type config struct {
	Size     size      `json:"size"`
	Current  uuid.UUID `json:"current"`
	Profiles []preset  `json:"profiles"`
}

type preset struct {
	UUID  uuid.UUID `json:"uuid"`
	Title string    `json:"title"`
	ID    string    `json:"id"`
	*rpcfetch.Activity
}

type size struct {
	Width  float32 `json:"width"`  // The number of units along the X axis.
	Height float32 `json:"height"` // The number of units along the Y axis.

}

type profLastCache struct {
	uuid  uuid.UUID
	index int
}

var (
	profLast atomic.Value
)

func (c *config) profile() preset {
	confLock.RLock()
	defer confLock.RUnlock()

	cache := profLast.Load().(profLastCache)
	if c.Current == cache.uuid {
		return c.Profiles[cache.index]
	}

	for i, prof := range c.Profiles {
		if prof.UUID == c.Current {
			profLast.Store(profLastCache{
				uuid:  c.Current,
				index: i,
			})
			return prof
		}
	}

	log.Fatalf(
		"configuration file corrupt: current profile %s does not exist",
		c.Current.String(),
	)
	return preset{}
}

func save() {
	nf, err := os.CreateTemp(path.Dir(confPath), ".rpcfetch.conf.*")
	if err != nil {
		log.Fatalf("error creating temporary configuration file: %s", err)
	}

	confLock.RLock()
	if err = gob.NewEncoder(nf).Encode(conf); err != nil {
		fmt.Printf("error writing configuration file: %s\n", err)
		os.Exit(1)
	}
	confLock.RUnlock()

	if err = nf.Close(); err != nil {
		log.Fatalf("error closing temporary configuration file: %s", err)
	}

	if err = os.Rename(nf.Name(), confPath); err != nil {
		log.Fatalf("error renaming configuration file: %s", err)
	}
	log.Printf("saved configuration to %s", confPath)
}

// sample config so the program works out of the box
var defaultConfig = config{
	Size: size{
		Width: 1 << 10,
		// will default to MinSize
		Height: 0,
	},

	Current: defaultUUID,
	Profiles: []preset{
		func() preset {
			p := copyTemplate()
			p.UUID = defaultUUID
			p.Title = "Default"
			return p
		}(),
	},
}

func copyTemplate() preset {
	p := templateProfile
	p.UUID = uuid.New()
	act := *p.Activity
	ast := *act.Assets
	act.Assets = &ast
	p.Activity = &act
	return p
}

var templateProfile = preset{
	ID: "1252927154480611351",
	Activity: &rpcfetch.Activity{
		State:   "%used / %total",
		Details: "%1min %5min %15min",
		Assets: &rpcfetch.ActivityAssets{
			LargeImage: "yorha",
			LargeText:  "%hostname",
			SmallImage: "flan",
			SmallText:  "PID: %pid",
		},
	},
}