package marketing

import (
	"encoding/json"
	"strings"
)

// QualityCheckKey identifies a completeness / SEO signal.
type QualityCheckKey string

const (
	CheckTitle           QualityCheckKey = "title"
	CheckDescription     QualityCheckKey = "description"
	CheckMetaTitle       QualityCheckKey = "meta_title"
	CheckMetaDescription QualityCheckKey = "meta_description"
	CheckCategory        QualityCheckKey = "category"
	CheckAttributes      QualityCheckKey = "attributes"
	CheckImage           QualityCheckKey = "image"
)

// QualityCheck is one weighted gate in the score.
type QualityCheck struct {
	Passed bool   `json:"passed"`
	Weight int    `json:"weight"`
	Label  string `json:"label"`
}

// QualityResult is a 0–100 completeness / SEO score.
type QualityResult struct {
	Score    int                                `json:"score"`
	MaxScore int                                `json:"max_score"`
	Grade    string                             `json:"grade"`
	Checks   map[QualityCheckKey]QualityCheck   `json:"checks"`
}

// ProductInput is the field snapshot used for scoring (no DB column required).
type ProductInput struct {
	Name                 string
	ProcessedName        string
	Description          string
	ProcessedDescription string
	MetaTitle            string
	MetaDescription      string
	Category             string
	Attributes           any
	ProcessedAttributes  any
	MappedData           map[string]any
}

var qualityWeights = map[QualityCheckKey]int{
	CheckTitle:           20,
	CheckDescription:     20,
	CheckMetaTitle:       15,
	CheckMetaDescription: 15,
	CheckCategory:        10,
	CheckAttributes:      10,
	CheckImage:           10,
}

var qualityLabels = map[QualityCheckKey]string{
	CheckTitle:           "Title",
	CheckDescription:     "Description",
	CheckMetaTitle:       "Meta title",
	CheckMetaDescription: "Meta description",
	CheckCategory:        "Category",
	CheckAttributes:      "Attributes",
	CheckImage:           "Image",
}

var qualityOrder = []QualityCheckKey{
	CheckTitle, CheckDescription, CheckMetaTitle, CheckMetaDescription,
	CheckCategory, CheckAttributes, CheckImage,
}

func hasText(value string, minLen int) bool {
	return len(strings.TrimSpace(value)) >= minLen
}

func countAttributes(value any) int {
	if value == nil {
		return 0
	}
	switch v := value.(type) {
	case []any:
		return len(v)
	case map[string]any:
		return len(v)
	case string:
		s := strings.TrimSpace(v)
		if s == "" || s == "{}" || s == "[]" || s == "null" {
			return 0
		}
		var arr []any
		if err := json.Unmarshal([]byte(s), &arr); err == nil {
			return len(arr)
		}
		var obj map[string]any
		if err := json.Unmarshal([]byte(s), &obj); err == nil {
			return len(obj)
		}
		return 0
	case []byte:
		return countAttributes(string(v))
	default:
		b, err := json.Marshal(v)
		if err != nil {
			return 0
		}
		return countAttributes(string(b))
	}
}

func hasImage(mapped map[string]any) bool {
	if mapped == nil {
		return false
	}
	keys := []string{"image", "image_link", "image_url", "images", "main_image", "primary_image", "picture", "photo"}
	for _, key := range keys {
		raw, ok := mapped[key]
		if !ok || raw == nil {
			continue
		}
		switch v := raw.(type) {
		case string:
			if strings.TrimSpace(v) != "" {
				return true
			}
		case []any:
			if len(v) > 0 {
				return true
			}
		}
	}
	return false
}

func gradeFromScore(score int) string {
	switch {
	case score >= 90:
		return "A"
	case score >= 75:
		return "B"
	case score >= 60:
		return "C"
	case score >= 40:
		return "D"
	default:
		return "F"
	}
}

// ComputeProductQualityScore scores completeness + SEO fields (0–100).
func ComputeProductQualityScore(in ProductInput) QualityResult {
	mappedName := ""
	mappedDesc := ""
	if in.MappedData != nil {
		if s, ok := in.MappedData["name"].(string); ok {
			mappedName = s
		} else if s, ok := in.MappedData["title"].(string); ok {
			mappedName = s
		}
		if s, ok := in.MappedData["description"].(string); ok {
			mappedDesc = s
		}
	}

	passed := map[QualityCheckKey]bool{
		CheckTitle: hasText(in.ProcessedName, 3) || hasText(in.Name, 3) || hasText(mappedName, 3),
		CheckDescription: hasText(in.ProcessedDescription, 20) || hasText(in.Description, 20) ||
			hasText(mappedDesc, 20),
		CheckMetaTitle:       hasText(in.MetaTitle, 10),
		CheckMetaDescription: hasText(in.MetaDescription, 40),
		CheckCategory:        hasText(in.Category, 1),
		CheckAttributes:      countAttributes(in.ProcessedAttributes) > 0 || countAttributes(in.Attributes) > 0,
		CheckImage:           hasImage(in.MappedData),
	}

	score := 0
	checks := make(map[QualityCheckKey]QualityCheck, len(qualityOrder))
	for _, key := range qualityOrder {
		w := qualityWeights[key]
		ok := passed[key]
		if ok {
			score += w
		}
		checks[key] = QualityCheck{Passed: ok, Weight: w, Label: qualityLabels[key]}
	}

	return QualityResult{
		Score:    score,
		MaxScore: 100,
		Grade:    gradeFromScore(score),
		Checks:   checks,
	}
}

// ScoreFromProductMap builds ProductInput from a catalog row map and scores it.
func ScoreFromProductMap(m map[string]any) QualityResult {
	in := ProductInput{
		Name:                 asString(m["name"]),
		ProcessedName:        asString(m["processed_name"]),
		Description:          asString(m["description"]),
		ProcessedDescription: asString(m["processed_description"]),
		MetaTitle:            asString(m["meta_title"]),
		MetaDescription:      asString(m["meta_description"]),
		Category:             asString(m["category"]),
		Attributes:           m["attributes"],
		ProcessedAttributes:  m["processed_attributes"],
	}
	if md, ok := m["mapped_data"].(map[string]any); ok {
		in.MappedData = md
	} else if raw, ok := m["mapped_data"].([]byte); ok && len(raw) > 0 {
		var obj map[string]any
		if json.Unmarshal(raw, &obj) == nil {
			in.MappedData = obj
		}
	} else if s := asString(m["mapped_data"]); s != "" {
		var obj map[string]any
		if json.Unmarshal([]byte(s), &obj) == nil {
			in.MappedData = obj
		}
	}
	return ComputeProductQualityScore(in)
}

func asString(v any) string {
	switch t := v.(type) {
	case string:
		return t
	case []byte:
		return string(t)
	case nil:
		return ""
	default:
		return ""
	}
}