package main

import (
	"context"
	"flag"

	log "github.com/sirupsen/logrus"
)

// Compile-time configurations.
const (
	// Number of tracks to fetch into a buffer.
	fetchingBuffer = 100

	// Number of seconds to wait before rechecking the lazy fetcher.
	fetchingTimeout = 3

	// Number of tracks to eagerly load.
	loadEager = 50

	// Number of tracks to lazily load ahead of the cursor.
	loadLookahead = 50

	// Number of seconds to wait before rechecking how many trackers are loaded
	// ahead of the cursor.
	loadTimeout = 3
)

// TODO: Compile-time variables.
// These should be set by the linker.
// e.g. `go build -ldflags="-X 'main.VERSION=0.1.2'"`
// var (
// 	VERSION = ""
// )

// Run-time configurations.
var (
	verbose = flag.Bool("verbose", false, "Show debugging messages (same as '-log-level=trace')")
	quiet = flag.Bool("quiet", false, "Suppress messages (same as '-log-level=panic')")
	log_level = flag.String("log-level", "", "Set logging level to `[trace|debug|info|warning|error|fatal|panic]`")
	// TODO: log_file = flag.String("log-file", "", "Log to `file`")
	color = flag.Bool("color", true, "Display in color")
	port = flag.Int("port", 8080, "Spotify authenticator port")
	cache = flag.String("cache", "", "Cache `directory`")
	no_cache = flag.Bool("no-cache", false, "Do not use cached authentication, do not cache authentication")
	device = flag.String("device", "", "Spotify device `ID`")
	list_devices = flag.Bool("list-devices", false, "List available Spotify devices and exit")
	// TODO: version = flag.Bool("version", false, "List version and exit")
)

// Create a pointer to a value, especially a string.
// Credit to `https://stackoverflow.com/a/30716481`:
func Pointer[T any](v T) *T {
	return &v
}

// Create a context with configurations applied.
func ConfiguredContext() context.Context {
	ctx := context.Background()

	flag.Parse()

	// If `-color` or `-color=true:
	if *color {
		log.SetFormatter(&log.TextFormatter{ForceColors: true, FullTimestamp: false})
	} else {
		log.SetFormatter(&log.TextFormatter{DisableColors: true, FullTimestamp: false})
	}

	// Prioritize explicit `-log-level`, then `-quiet`, then `-verbose`.
	if *log_level == "" {
		if *verbose {
			log_level = Pointer("trace")
		}
		if *quiet {
			log_level = Pointer("panic")
		}
	}
	switch *log_level {
	case "trace":
		log.SetLevel(log.TraceLevel)
	case "debug":
		log.SetLevel(log.DebugLevel)
	case "info":
		log.SetLevel(log.InfoLevel)
	case "warn":
		log.SetLevel(log.WarnLevel)
	case "error":
		log.SetLevel(log.ErrorLevel)
	case "fatal":
		log.SetLevel(log.FatalLevel)
	case "panic":
		log.SetLevel(log.PanicLevel)
	default:
		log.SetLevel(log.ErrorLevel)
	}

	ctx = context.WithValue(ctx, "authport", *port)

	if *cache == "" {
		cache = Pointer(default_cache_dir())
	}

	// Signal `-no-cache` by forcing `-cache=''`.
	if *no_cache {
		cache = Pointer("")
	}
	ctx = context.WithValue(ctx, "cachedir", *cache)

	// Signal `-list-devices` by forcing `-device=''`.
	if *list_devices {
		device = Pointer("")
	}
	ctx = context.WithValue(ctx, "device", *device)

	// TODO: Signal `-version` by setting the version variable.
	// ctx = context.WithValue(ctx, "version", VERSION)

	return ctx
}