package cli

import (
	"context"
	"flag"
	"fmt"
	"strings"

	"github.com/peterbourgon/ff/v3/ffcli"

	metrics "edge-infra.dev/pkg/lib/gcp/monitoring/metrics"
	"edge-infra.dev/pkg/lib/gcp/monitoring/monutil"
)

type compareArgsT struct {
	byMetric  bool
	byProject bool
}

var compareArgs compareArgsT
var compareFlagSet = newCompareFlagSet(&compareArgs)

func newCompareFlagSet(compareArgs *compareArgsT) *flag.FlagSet {
	comparef := newFlagSet("compare")
	comparef.BoolVar(&compareArgs.byProject, "by-project", false, "Metric descriptor comparisons sorted by project ID. (cannot be used with --by-metric)")
	comparef.BoolVar(&compareArgs.byMetric, "by-metric", false, "Metric descriptors comparisons sorted by metric. (cannot be used with --by-project)")
	return comparef
}

var compareCmd = &ffcli.Command{
	Name:       "compare",
	ShortUsage: "compare [flags]",
	ShortHelp:  "compare metric descriptor labels",
	LongHelp: strings.TrimSpace(`
Compares metricDescriptor labels from two or more projects.
`),
	FlagSet: withGlobalFlags(compareFlagSet),
	Exec:    runCompare,
}

func runCompare(ctx context.Context, args []string) error {
	if len(args) > 0 {
		Fatalf("too many non-flag arguments: %q", args)
	}
	if !checkCompareFlags() || !checkGlobalFlags() {
		return flag.ErrHelp
	}

	// retrieve metric descriptors as list
	projects := strings.Split(strings.ReplaceAll(projectID, " ", ""), ",")
	d, err := retrieveDescriptors(ctx, projects)
	if err != nil {
		return Errorf("failed to metricDescriptors for multiple projects: %w", err)
	}

	// necessary when specifying multiple projects as foreman is a multi-project source
	if filterForeman {
		projects := strings.Split(strings.ReplaceAll(projectID, " ", ""), ",")
		d, err = d.FilterProjects(projects)
		if err != nil {
			return err
		}
	}

	switch {
	case compareArgs.byMetric && !jsonFormat:
		_ = metrics.TmplMetricCompare.Execute(Stdout, d.CompareMetrics())

	case compareArgs.byProject && !jsonFormat:
		_ = metrics.TmplProjectCompare.Execute(Stdout, d.CompareProjects())

	case compareArgs.byMetric && jsonFormat:
		_ = metrics.TmplJSON.Execute(Stdout, d.CompareMetrics())

	case compareArgs.byProject && jsonFormat:
		_ = metrics.TmplJSON.Execute(Stdout, d.CompareProjects())

	case !compareArgs.byMetric && !compareArgs.byProject && jsonFormat:
		_ = metrics.TmplJSON.Execute(Stdout, d.Compare())

	default:
		_ = metrics.TmplDescCompare.Execute(Stdout, d.Compare())
	}

	if !silent {
		fmt.Printf("\n%s", monutil.White(mmBroomTitle))
	}
	return nil
}

// checkCompareFlags validates the required Compare subcommand flags have been provided.
func checkCompareFlags() bool {
	if compareArgs.byMetric && compareArgs.byProject {
		fmt.Println("Error: 'by-metric' and 'by-project' were selected - only one sort method allowed")
		return false
	}

	return true
}