package main

import (
	"bytes"
	"encoding/json"
	"flag"
	"fmt"
	"os"
	"sort"
	"strings"

	local_metrics "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/metrics"
	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
)

var (
	node   = flag.String("node", "", "File to export storage node metrics to.")
	ir     = flag.String("ir", "", "File to export innerring node metrics to.")
	format = flag.String("format", "json", "Format to export in. Supported formats: json (default), md.")
)

func main() {
	flag.Parse()

	if *node != "" && *ir != "" {
		fmt.Println("-node and -ir flags are mutually exclusive")
		os.Exit(1)
	}

	var filename string
	switch {
	case *node != "":
		_ = local_metrics.NewNodeMetrics()
		filename = *node
	case *ir != "":
		_ = local_metrics.NewInnerRingMetrics()
		filename = *ir

	default:
		flag.Usage()
		os.Exit(1)
	}

	var data []byte
	var err error

	ds := metrics.DescribeAll()
	switch *format {
	case "md":
		sort.Slice(ds, func(i, j int) bool {
			return ds[i].Name < ds[j].Name
		})
		b := bytes.NewBuffer(nil)
		b.WriteString("# FrostFS Node prometheus metrics\n")
		b.WriteString("Name | Description | Constant labels | Variable labels\n")
		b.WriteString("-- | -- | -- | --\n")
		for i := range ds {
			constLabels := make([]string, 0, len(ds[i].ConstantLabels))
			for key, value := range ds[i].ConstantLabels {
				constLabels = append(constLabels, fmt.Sprintf("`%s=%s`", key, value))
			}

			// FIXME omg do it better
			ss := make([]string, len(ds[i].VariableLabels))
			copy(ss, ds[i].VariableLabels)
			for i := range ss {
				ss[i] = fmt.Sprintf("`%s`", ss[i])
			}
			varLabels := strings.Join(ss, "<br>")
			fmt.Fprintf(b, "`%s` | %s | %s | %s\n", ds[i].Name, ds[i].Help, strings.Join(constLabels, "<br>"), varLabels)
		}
		data = b.Bytes()
	default:
		data, err = json.Marshal(ds)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Could not parse marshal: %v\n", err)
			os.Exit(1)
		}
	}

	if err := os.WriteFile(filename, data, 0o644); err != nil {
		fmt.Fprintf(os.Stderr, "Could write to file: %v\n", err)
		os.Exit(1)
	}
}