package main

import (
	"fmt"
	"log/slog"
	"net/http"
	"net/http/pprof"
	"os"
	"runtime"

	"esdi/cmd"
	"esdi/config"

	"github.com/arl/statsviz"
)

// NOTE: in go we have the init() function. Its a function that runs before
// everything else in a package. Make use of that

func initApplication() {
	fmt.Fprint(os.Stdout, "\x1b]0;ESDI\x07")

	// 1. This is the first initialization setup we do so we can log
	err := setupLogger()
	if err != nil {
		panic("failed to open logging file: " + err.Error())
	}

	// 2. This is the second thing we setup because we need some stuff to run
	// other things
	err = config.Setup("./config/config.yaml")
	if err != nil {
		panic("failed to setup config: " + err.Error())
	}

	// Performance analysis
	if config.GetCfg().MetricsServer {
		slog.Info("Setting up metrics server...")
		err = runStatviz()
		if err != nil {
			slog.Error(fmt.Sprintf("failed to setup metrics server: %+v", err))
		}
	}
}

func setupLogger() error {
	output, err := os.OpenFile("./output.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o755)
	if err != nil {
		return err
	}

	logger := slog.New(
		slog.NewTextHandler(output, &slog.HandlerOptions{
			Level: slog.LevelDebug,
		}),
	)

	slog.SetDefault(logger)

	return nil
}

func runStatviz() error {
	mux := http.NewServeMux()
	err := statsviz.Register(mux, statsviz.Root("/"))
	if err != nil {
		return err
	}

	runtime.SetBlockProfileRate(1)
	runtime.SetMutexProfileFraction(1)
	mux.HandleFunc("/debug/pprof/", pprof.Index)
	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)

	go func() {
		err := http.ListenAndServe("localhost:8001", mux)
		if err != nil {
			slog.Error("Failed to set up server for statsviz", "err", err)
		}
	}()

	return nil
}

func main() {
	initApplication()

	// Launches the cobra package stuff
	cmd.Execute()
}