package outreach

import (
	"fmt"
	"strings"

	libkg "haixun-backend/internal/library/knowledge"
	libplacement "haixun-backend/internal/library/placement"
	brandentity "haixun-backend/internal/model/brand/domain/entity"
	branddomain "haixun-backend/internal/model/brand/domain/usecase"
	scanpostusecase "haixun-backend/internal/model/scan_post/domain/usecase"
)

func FindGraphNode(nodes []libkg.Node, nodeID string) *libkg.Node {
	nodeID = strings.TrimSpace(nodeID)
	if nodeID == "" {
		return nil
	}
	for i := range nodes {
		if nodes[i].ID == nodeID {
			return &nodes[i]
		}
	}
	return nil
}

func BuildPlacementReason(post *scanpostusecase.ScanPostSummary) string {
	if post == nil {
		return ""
	}
	parts := []string{}
	if post.Priority == "gold" {
		parts = append(parts, "雙軌命中（相關+近期）")
	} else if post.Priority == "recent" {
		parts = append(parts, "近期軌命中")
	}
	if post.SolvedByProduct {
		parts = append(parts, "產品可解此需求")
	}
	if post.ProductFitScore > 0 {
		parts = append(parts, fmt.Sprintf("產品匹配 %d", post.ProductFitScore))
	}
	return strings.Join(parts, "；")
}

func MergePlacementReason(base string, node *libkg.Node, post *scanpostusecase.ScanPostSummary) string {
	parts := []string{}
	if strings.TrimSpace(base) != "" {
		parts = append(parts, strings.TrimSpace(base))
	}
	if node != nil {
		if strings.TrimSpace(node.PlacementValue) != "" {
			parts = append(parts, "置入價值 "+strings.TrimSpace(node.PlacementValue))
		}
		if node.ProductFitScore > 0 && (post == nil || post.ProductFitScore == 0) {
			parts = append(parts, fmt.Sprintf("節點產品匹配 %d", node.ProductFitScore))
		}
	}
	return strings.Join(parts, "；")
}

func ProductBriefForBrand(brand *branddomain.BrandSummary, productID, searchTag, postText string) string {
	if brand == nil {
		return ""
	}
	if product := PickProductForOutreach(brand, productID, searchTag, postText); product != nil {
		merged := libplacement.BuildMergedProductContext(brand.DisplayName, product.ProductContext, product.Label)
		merged = libplacement.ApplyPlacementURL(merged, product.PlacementURL)
		if pb := libplacement.ProductBriefFromContext(merged); pb != "" {
			return pb
		}
	}
	if pb := libplacement.ProductBriefFromContext(brand.ProductContext); pb != "" {
		return pb
	}
	return strings.TrimSpace(brand.ProductBrief)
}

func PickProductForOutreach(brand *branddomain.BrandSummary, preferredProductID, searchTag, postText string) *branddomain.ProductSummary {
	if brand == nil || len(brand.Products) == 0 {
		return nil
	}
	entities := make([]brandentity.Product, len(brand.Products))
	for i := range brand.Products {
		entities[i] = brandentity.Product{
			ID:             brand.Products[i].ID,
			Label:          brand.Products[i].Label,
			ProductContext: brand.Products[i].ProductContext,
			MatchTags:      append([]string(nil), brand.Products[i].MatchTags...),
		}
	}
	if picked := libplacement.RecommendProductForPost(entities, searchTag, postText, preferredProductID); picked != nil {
		for i := range brand.Products {
			if brand.Products[i].ID == picked.ID {
				return &brand.Products[i]
			}
		}
	}
	if id := strings.TrimSpace(preferredProductID); id != "" {
		for i := range brand.Products {
			if brand.Products[i].ID == id {
				return &brand.Products[i]
			}
		}
	}
	return &brand.Products[0]
}