package shopify

import (
	"encoding/json"
	"strings"
	"time"
)

const (
	defaultBatchSize     = 25
	defaultSyncLimit     = 200
	maxBatchSize         = 100
	maxSyncLimit         = 1000
	maxOrdersSyncLimit   = 5000
	maxProductIDMap      = 5000
	maxScheduleIntervalH = 168 // 7 days
)

// SyncOptions is stored as JSON on shopify_configs.sync_options.
type SyncOptions struct {
	ProductIDs            map[string]int64 `json:"product_ids"`
	MatchStrategy         string           `json:"match_strategy"`
	BatchSize             int              `json:"batch_size"`
	SyncLimit             int              `json:"sync_limit"`
	PendingSync           bool             `json:"pending_sync"`
	PendingOrdersSync     bool             `json:"pending_orders_sync"`
	LastSyncStatus        string           `json:"last_sync_status"`
	LastSyncError         string           `json:"last_sync_error"`
	LastSyncSummary       *SyncSummary     `json:"last_sync_summary,omitempty"`
	LastOrdersSyncStatus  string           `json:"last_orders_sync_status"`
	LastOrdersSyncError   string           `json:"last_orders_sync_error"`
	LastOrdersSyncedAt    *time.Time       `json:"last_orders_synced_at,omitempty"`
	OrdersSyncLimit       int              `json:"orders_sync_limit"`
	DryRun                bool             `json:"dry_run"`
	ScheduleIntervalHours int              `json:"schedule_interval_hours"`
	SchedulePaused        bool             `json:"schedule_paused"`
	// One-shot selection for the next product sync (cleared when sync finishes).
	SyncFilterStatus   string   `json:"sync_filter_status,omitempty"`
	SyncFilterCategory string   `json:"sync_filter_category,omitempty"`
	SyncOnlyIDs        []string `json:"sync_only_ids,omitempty"`

	// Auth (Dev Dashboard client_credentials). Legacy permanent tokens leave these empty.
	AuthMode        string     `json:"auth_mode,omitempty"`
	ClientID        string     `json:"client_id,omitempty"`
	ClientSecretEnc string     `json:"client_secret_enc,omitempty"`
	TokenExpiresAt  *time.Time `json:"token_expires_at,omitempty"`
}

func parseSyncOptions(raw []byte) SyncOptions {
	opt := SyncOptions{
		ProductIDs:    map[string]int64{},
		MatchStrategy: "sku",
		BatchSize:     defaultBatchSize,
		SyncLimit:     defaultSyncLimit,
	}
	if len(raw) == 0 {
		return opt
	}
	_ = json.Unmarshal(raw, &opt)
	if opt.ProductIDs == nil {
		opt.ProductIDs = map[string]int64{}
	}
	pruneStringInt64Map(opt.ProductIDs, maxProductIDMap)
	if opt.MatchStrategy == "" {
		opt.MatchStrategy = "sku"
	}
	if opt.BatchSize <= 0 || opt.BatchSize > maxBatchSize {
		opt.BatchSize = defaultBatchSize
	}
	if opt.SyncLimit <= 0 || opt.SyncLimit > maxSyncLimit {
		opt.SyncLimit = defaultSyncLimit
	}
	if opt.OrdersSyncLimit < 0 || opt.OrdersSyncLimit > maxOrdersSyncLimit {
		opt.OrdersSyncLimit = 0
	}
	if opt.ScheduleIntervalHours < 0 || opt.ScheduleIntervalHours > maxScheduleIntervalH {
		opt.ScheduleIntervalHours = 0
	}
	opt.SyncOnlyIDs = pruneSyncOnlyIDs(opt.SyncOnlyIDs, maxSyncOnlyIDs)
	return opt
}

// resolveScheduleInterval maps schedule_interval_hours to a duration (default when hours<=0).
func resolveScheduleInterval(hours int, defaultInterval time.Duration) time.Duration {
	if defaultInterval <= 0 {
		defaultInterval = 6 * time.Hour
	}
	if hours > 0 {
		return time.Duration(hours) * time.Hour
	}
	return defaultInterval
}

// isDueForSchedule reports whether last sync is missing or older than interval.
func isDueForSchedule(last *time.Time, now time.Time, interval time.Duration) bool {
	if last == nil {
		return true
	}
	return now.Sub(last.UTC()) >= interval
}

// shouldEnqueueScheduled reports whether auto product sync should run now.
// Paused schedules never enqueue; interval 0 uses defaultInterval (worker default 6h).
func shouldEnqueueScheduled(paused bool, hours int, last *time.Time, now time.Time, defaultInterval time.Duration) bool {
	if paused {
		return false
	}
	return isDueForSchedule(last, now, resolveScheduleInterval(hours, defaultInterval))
}

func firstNonEmpty(vals ...string) string {
	for _, v := range vals {
		if strings.TrimSpace(v) != "" {
			return strings.TrimSpace(v)
		}
	}
	return ""
}

func pruneStringInt64Map(m map[string]int64, max int) {
	if max <= 0 || len(m) <= max {
		return
	}
	n := len(m) - max
	for k := range m {
		delete(m, k)
		n--
		if n <= 0 {
			return
		}
	}
}