package main

import (
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"

	pb "git.ipng.ch/ipng/nginx-logtail/proto/logtailpb"
)

// sharedFlags holds the flags common to every subcommand.
type sharedFlags struct {
	targets []string
	jsonOut bool
	website string
	prefix  string
	uri     string
	status  string // kept as string so we can tell "unset" from "0"
}

// bindShared registers the shared flags on fs and returns a pointer to the
// populated struct. Call fs.Parse before reading the struct.
func bindShared(fs *flag.FlagSet) (*sharedFlags, *string) {
	sf := &sharedFlags{}
	target := fs.String("target", "localhost:9090", "comma-separated host:port list")
	fs.BoolVar(&sf.jsonOut, "json", false, "emit newline-delimited JSON")
	fs.StringVar(&sf.website, "website", "", "filter: website")
	fs.StringVar(&sf.prefix, "prefix", "", "filter: client prefix")
	fs.StringVar(&sf.uri, "uri", "", "filter: request URI")
	fs.StringVar(&sf.status, "status", "", "filter: HTTP status code (integer)")
	return sf, target
}

func (sf *sharedFlags) resolve(target string) {
	sf.targets = parseTargets(target)
}

func parseTargets(s string) []string {
	seen := make(map[string]bool)
	var out []string
	for _, t := range strings.Split(s, ",") {
		t = strings.TrimSpace(t)
		if t == "" || seen[t] {
			continue
		}
		seen[t] = true
		out = append(out, t)
	}
	return out
}

func buildFilter(sf *sharedFlags) *pb.Filter {
	if sf.website == "" && sf.prefix == "" && sf.uri == "" && sf.status == "" {
		return nil
	}
	f := &pb.Filter{}
	if sf.website != "" {
		f.Website = &sf.website
	}
	if sf.prefix != "" {
		f.ClientPrefix = &sf.prefix
	}
	if sf.uri != "" {
		f.HttpRequestUri = &sf.uri
	}
	if sf.status != "" {
		n, err := strconv.Atoi(sf.status)
		if err != nil {
			fmt.Fprintf(os.Stderr, "--status: %v\n", err)
			os.Exit(1)
		}
		n32 := int32(n)
		f.HttpResponse = &n32
	}
	return f
}

func parseWindow(s string) pb.Window {
	switch s {
	case "1m":
		return pb.Window_W1M
	case "5m":
		return pb.Window_W5M
	case "15m":
		return pb.Window_W15M
	case "60m":
		return pb.Window_W60M
	case "6h":
		return pb.Window_W6H
	case "24h":
		return pb.Window_W24H
	default:
		fmt.Fprintf(os.Stderr, "--window: unknown value %q; valid: 1m 5m 15m 60m 6h 24h\n", s)
		os.Exit(1)
		panic("unreachable")
	}
}

func parseGroupBy(s string) pb.GroupBy {
	switch s {
	case "website":
		return pb.GroupBy_WEBSITE
	case "prefix":
		return pb.GroupBy_CLIENT_PREFIX
	case "uri":
		return pb.GroupBy_REQUEST_URI
	case "status":
		return pb.GroupBy_HTTP_RESPONSE
	default:
		fmt.Fprintf(os.Stderr, "--group-by: unknown value %q; valid: website prefix uri status\n", s)
		os.Exit(1)
		panic("unreachable")
	}
}

func dieUsage(fs *flag.FlagSet, msg string) {
	fmt.Fprintln(os.Stderr, msg)
	fs.PrintDefaults()
	os.Exit(1)
}