package canvas

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

	"infinite-canvas/backend/internal/model"
)

// clientAssetPayload 把数据库里的素材记录补齐为前端素材合同可消费的 JSON。
// 工作流等内部写入路径可能绕过 UpsertUserAsset，导致 payload 缺少 coverUrl、tags 或时间戳。
func ClientAssetPayload(asset model.Asset) json.RawMessage {
	raw := strings.TrimSpace(asset.PayloadJSON)
	if raw == "" {
		return nil
	}
	var payload map[string]any
	if err := json.Unmarshal([]byte(raw), &payload); err != nil || payload == nil {
		return json.RawMessage(raw)
	}
	if _, ok := payload["coverUrl"]; !ok {
		payload["coverUrl"] = deriveAssetCoverURL(payload)
	}
	if _, ok := payload["tags"]; !ok {
		payload["tags"] = []string{}
	}
	if _, ok := payload["createdAt"]; !ok {
		payload["createdAt"] = formatClientAssetTime(asset.CreatedAt)
	}
	if _, ok := payload["updatedAt"]; !ok {
		payload["updatedAt"] = formatClientAssetTime(asset.UpdatedAt)
	}
	if data, ok := payload["data"].(map[string]any); ok {
		kind, _ := payload["kind"].(string)
		switch kind {
		case "image", "video":
			ensurePositiveAssetDimension(data, "width")
			ensurePositiveAssetDimension(data, "height")
		}
	}
	encoded, err := json.Marshal(payload)
	if err != nil {
		return json.RawMessage(raw)
	}
	return encoded
}

func deriveAssetCoverURL(payload map[string]any) string {
	if value, ok := payload["coverUrl"].(string); ok && strings.TrimSpace(value) != "" {
		return value
	}
	data, ok := payload["data"].(map[string]any)
	if !ok {
		return ""
	}
	for _, key := range []string{"dataUrl", "url"} {
		if value, ok := data[key].(string); ok && strings.TrimSpace(value) != "" {
			return value
		}
	}
	if storageKey, ok := data["storageKey"].(string); ok {
		return resourceURLFromStorageKey(storageKey)
	}
	return ""
}

func resourceURLFromStorageKey(storageKey string) string {
	storageKey = strings.TrimSpace(storageKey)
	if !strings.HasPrefix(storageKey, "resource:") {
		return ""
	}
	resourceID := strings.TrimSpace(strings.TrimPrefix(storageKey, "resource:"))
	if resourceID == "" {
		return ""
	}
	return "/api/resources/" + resourceID + "/file"
}

func ensurePositiveAssetDimension(data map[string]any, key string) {
	value, ok := jsonNumberValue(data[key])
	if !ok || value <= 0 {
		data[key] = 1
	}
}

func jsonNumberValue(value any) (float64, bool) {
	switch item := value.(type) {
	case float64:
		return item, true
	case int:
		return float64(item), true
	case int64:
		return float64(item), true
	case json.Number:
		parsed, err := item.Float64()
		return parsed, err == nil
	default:
		return 0, false
	}
}

func formatClientAssetTime(value time.Time) string {
	if value.IsZero() {
		return time.Now().UTC().Format(time.RFC3339Nano)
	}
	return value.UTC().Format(time.RFC3339Nano)
}