package hostfloor

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"github.com/carlosframework/platform/internal/rootparticipation"
	"github.com/carlosframework/platform/internal/safefile"
)

func (d Disk) CheckParticipation(ctx context.Context, dataDir string, requireDirectory bool) error {
	return d.WithParticipation(ctx, func(ctx context.Context, l rootparticipation.Ledger) error {
		if err := l.Idle(ctx); err != nil {
			return err
		}
		return checkLegacyParticipation(dataDir, false)
	}, func() error { return checkLegacyParticipation(dataDir, requireDirectory) })
}

func checkLegacyParticipation(dataDir string, requireDirectory bool) error {
	dir := filepath.Join(dataDir, ".hostexec")
	f, err := safefile.OpenDir(dir)
	if errors.Is(err, os.ErrNotExist) && !requireDirectory {
		return nil
	}
	if err != nil {
		return fmt.Errorf("%s cannot be listed: %v", dir, err)
	}
	defer f.Close()
	entries, err := f.ReadDir(-1)
	if err != nil {
		return fmt.Errorf("%s cannot be listed: %v", dir, err)
	}
	if len(entries) == 0 {
		return nil
	}
	names := make([]string, 0, len(entries))
	for _, e := range entries {
		names = append(names, e.Name())
	}
	sort.Strings(names)
	if len(names) > 3 {
		names = append(names[:3], fmt.Sprintf("and %d more", len(entries)-3))
	}
	return fmt.Errorf("this box takes part in a running claim operation (%s holds %s)", dir, strings.Join(names, ", "))
}