package processing

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"

	"github.com/descrybe/descrybe-v2/apps/api/internal/company"
)

// FieldEnhanceInputHash is stored on processed_products.field_sources so re-runs
// can skip the LLM when enhance inputs are unchanged (mirrors feed content_hash).
const FieldEnhanceInputHash = "enhance_input_hash"

// enhanceInputHashVersion bumps when the enhance prompt/schema changes so prior
// hashes are invalidated and products re-enhance once.
const enhanceInputHashVersion = "3"

// HashEnhanceInput returns a stable hex SHA-256 of the inputs that feed the
// enhance LLM (same compaction as ProductEnhanceUser / CompactBrandPrompt).
// Empty inputs still produce a deterministic hash.
func HashEnhanceInput(category, name, description, brandPrompt, language, promptSystem, promptUser string, attrs map[string]any) string {
	langCode, err := company.ParseLanguage(language, true)
	if err != nil {
		langCode = company.DefaultLanguage
	}
	payload := map[string]any{
		"v":             enhanceInputHashVersion,
		"category":      SanitizeText(category),
		"name":          SanitizeText(truncateRunes(name, 200)),
		"description":   SanitizeText(truncateRunes(description, MaxProductDescRunes)),
		"brand_prompt":  CompactBrandPrompt(brandPrompt),
		"language":      langCode,
		"prompt_system": SanitizeText(truncateRunes(promptSystem, 4000)),
		"prompt_user":   SanitizeText(truncateRunes(promptUser, 4000)),
		"attrs":         CompactAttrs(attrs, MaxAttrKeys),
	}
	b, err := json.Marshal(payload)
	if err != nil {
		// Unreachable for map[string]any of strings/scalars; fall back so callers
		// never skip LLM on a broken hash.
		sum := sha256.Sum256([]byte(category + "\x00" + name + "\x00" + description))
		return hex.EncodeToString(sum[:])
	}
	sum := sha256.Sum256(b)
	return hex.EncodeToString(sum[:])
}

func enhanceHashFromMeta(raw any) string {
	m, ok := raw.(map[string]any)
	if !ok {
		return ""
	}
	h, _ := m["input_hash"].(string)
	return h
}

func enhanceStatusFromMeta(raw any) string {
	m, ok := raw.(map[string]any)
	if !ok {
		return ""
	}
	s, _ := m["status"].(string)
	return s
}