package localdb

import (
	"encoding/json"
	"fmt"
	"sort"
	"time"
)

// BuildConfigurationSnapshot serializes the full local configuration state.
func BuildConfigurationSnapshot(localCfg *LocalConfiguration) (string, error) {
	snapshot := map[string]interface{}{
		"id":                 localCfg.ID,
		"uuid":               localCfg.UUID,
		"server_id":          localCfg.ServerID,
		"project_uuid":       localCfg.ProjectUUID,
		"current_version_id": localCfg.CurrentVersionID,
		"is_active":          localCfg.IsActive,
		"name":               localCfg.Name,
		"items":              localCfg.Items,
		"total_price":        localCfg.TotalPrice,
		"custom_price":       localCfg.CustomPrice,
		"notes":              localCfg.Notes,
		"is_template":        localCfg.IsTemplate,
		"server_count":       localCfg.ServerCount,
		"server_model":       localCfg.ServerModel,
		"support_code":       localCfg.SupportCode,
		"article":            localCfg.Article,
		"pricelist_id":       localCfg.PricelistID,
		"only_in_stock":      localCfg.OnlyInStock,
		"line":               localCfg.Line,
		"price_updated_at":   localCfg.PriceUpdatedAt,
		"created_at":         localCfg.CreatedAt,
		"updated_at":         localCfg.UpdatedAt,
		"synced_at":          localCfg.SyncedAt,
		"sync_status":        localCfg.SyncStatus,
		"original_user_id":   localCfg.OriginalUserID,
		"original_username":  localCfg.OriginalUsername,
	}

	data, err := json.Marshal(snapshot)
	if err != nil {
		return "", fmt.Errorf("marshal configuration snapshot: %w", err)
	}
	return string(data), nil
}

// DecodeConfigurationSnapshot returns editable fields from one saved snapshot.
func DecodeConfigurationSnapshot(data string) (*LocalConfiguration, error) {
	var snapshot struct {
		ProjectUUID      *string          `json:"project_uuid"`
		IsActive         *bool            `json:"is_active"`
		Name             string           `json:"name"`
		Items            LocalConfigItems `json:"items"`
		TotalPrice       *float64         `json:"total_price"`
		CustomPrice      *float64         `json:"custom_price"`
		Notes            string           `json:"notes"`
		IsTemplate       bool             `json:"is_template"`
		ServerCount      int              `json:"server_count"`
		ServerModel      string           `json:"server_model"`
		SupportCode      string           `json:"support_code"`
		Article          string           `json:"article"`
		PricelistID      *uint            `json:"pricelist_id"`
		OnlyInStock      bool             `json:"only_in_stock"`
		Line             int              `json:"line"`
		PriceUpdatedAt   *time.Time       `json:"price_updated_at"`
		OriginalUserID   uint             `json:"original_user_id"`
		OriginalUsername string           `json:"original_username"`
	}

	if err := json.Unmarshal([]byte(data), &snapshot); err != nil {
		return nil, fmt.Errorf("unmarshal snapshot JSON: %w", err)
	}

	isActive := true
	if snapshot.IsActive != nil {
		isActive = *snapshot.IsActive
	}

	return &LocalConfiguration{
		IsActive:         isActive,
		ProjectUUID:      snapshot.ProjectUUID,
		Name:             snapshot.Name,
		Items:            snapshot.Items,
		TotalPrice:       snapshot.TotalPrice,
		CustomPrice:      snapshot.CustomPrice,
		Notes:            snapshot.Notes,
		IsTemplate:       snapshot.IsTemplate,
		ServerCount:      snapshot.ServerCount,
		ServerModel:      snapshot.ServerModel,
		SupportCode:      snapshot.SupportCode,
		Article:          snapshot.Article,
		PricelistID:      snapshot.PricelistID,
		OnlyInStock:      snapshot.OnlyInStock,
		Line:             snapshot.Line,
		PriceUpdatedAt:   snapshot.PriceUpdatedAt,
		OriginalUserID:   snapshot.OriginalUserID,
		OriginalUsername: snapshot.OriginalUsername,
	}, nil
}

type configurationSpecPriceFingerprint struct {
	Items       []configurationSpecPriceFingerprintItem `json:"items"`
	ServerCount int                                     `json:"server_count"`
	TotalPrice  *float64                                `json:"total_price,omitempty"`
	CustomPrice *float64                                `json:"custom_price,omitempty"`
}

type configurationSpecPriceFingerprintItem struct {
	LotName   string  `json:"lot_name"`
	Quantity  int     `json:"quantity"`
	UnitPrice float64 `json:"unit_price"`
}

// BuildConfigurationSpecPriceFingerprint returns a stable JSON key based on
// spec + price fields only, used for revision deduplication.
func BuildConfigurationSpecPriceFingerprint(localCfg *LocalConfiguration) (string, error) {
	items := make([]configurationSpecPriceFingerprintItem, 0, len(localCfg.Items))
	for _, item := range localCfg.Items {
		items = append(items, configurationSpecPriceFingerprintItem{
			LotName:   item.LotName,
			Quantity:  item.Quantity,
			UnitPrice: item.UnitPrice,
		})
	}
	sort.Slice(items, func(i, j int) bool {
		if items[i].LotName != items[j].LotName {
			return items[i].LotName < items[j].LotName
		}
		if items[i].Quantity != items[j].Quantity {
			return items[i].Quantity < items[j].Quantity
		}
		return items[i].UnitPrice < items[j].UnitPrice
	})

	payload := configurationSpecPriceFingerprint{
		Items:       items,
		ServerCount: localCfg.ServerCount,
		TotalPrice:  localCfg.TotalPrice,
		CustomPrice: localCfg.CustomPrice,
	}

	raw, err := json.Marshal(payload)
	if err != nil {
		return "", fmt.Errorf("marshal spec+price fingerprint: %w", err)
	}
	return string(raw), nil
}