package lagoon

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/pact"
)

// FrameworkScheduleID is the plugin id under which the scheduler lists the
// framework's own schedule entries, so the daily purge has the entry id
// summercms.lagoon[0]:deferred:purge.
const FrameworkScheduleID = "summercms.lagoon"

const (
	purgeAtKey     = "database.deferred_bindings.purge_at"
	purgeDaysKey   = "database.deferred_bindings.purge_days"
	defaultPurgeAt = "03:00"
	// defaultPurgeDays is WinterCMS's DeferredBinding::cleanUp(5).
	defaultPurgeDays = 5
)

var purgeAtPattern = regexp.MustCompile(`^([01][0-9]|2[0-3]):([0-5][0-9])$`)

// FrameworkSchedule returns the scheduled commands the framework itself
// runs: deferred:purge daily at database.deferred_bindings.purge_at ("HH:MM"
// in app.timezone, default "03:00"). An explicitly empty purge_at disables
// the entry; a malformed one is an error naming the key. A nil app or an app
// without config returns no entries and no error.
func FrameworkSchedule(app *backpack.App) ([]pact.ScheduledCommand, error) {
	if app == nil || app.Config == nil {
		return nil, nil
	}
	at := defaultPurgeAt
	if raw, ok := app.Config.Lookup(purgeAtKey); ok {
		switch v := raw.(type) {
		case nil:
			at = ""
		case string:
			at = strings.TrimSpace(v)
		default:
			return nil, fmt.Errorf("lagoon: %s must be a quoted \"HH:MM\" string, got %v", purgeAtKey, raw)
		}
	}
	if at == "" {
		return nil, nil
	}
	m := purgeAtPattern.FindStringSubmatch(at)
	if m == nil {
		return nil, fmt.Errorf("lagoon: %s %q is not HH:MM (00:00 to 23:59)", purgeAtKey, at)
	}
	hour, _ := strconv.Atoi(m[1])
	minute, _ := strconv.Atoi(m[2])
	return []pact.ScheduledCommand{{Command: "deferred:purge", Cadence: pact.DailyAt(hour, minute)}}, nil
}