package app

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jackc/pgx/v5/pgxpool"
	"golang.org/x/sync/singleflight"

	"github.com/geo-platform/tenant-api/internal/shared/auditlog"
	"github.com/geo-platform/tenant-api/internal/shared/auth"
	sharedcache "github.com/geo-platform/tenant-api/internal/shared/cache"
	sharedconfig "github.com/geo-platform/tenant-api/internal/shared/config"
	"github.com/geo-platform/tenant-api/internal/shared/middleware"
	"github.com/geo-platform/tenant-api/internal/shared/response"
)

type BrandService struct {
	pool           *pgxpool.Pool
	monitoringPool *pgxpool.Pool
	limits         sharedconfig.BrandLibraryConfig
	auditLogs      *auditlog.AsyncWriter
	cache          sharedcache.Cache
	cacheGroup     singleflight.Group
}

func NewBrandService(pool, monitoringPool *pgxpool.Pool, auditLogs *auditlog.AsyncWriter, limits sharedconfig.BrandLibraryConfig) *BrandService {
	return &BrandService{pool: pool, monitoringPool: monitoringPool, limits: limits, auditLogs: auditLogs}
}

func (s *BrandService) WithCache(c sharedcache.Cache) *BrandService {
	s.cache = c
	return s
}

// --- Brand CRUD ---

type BrandRequest struct {
	Name        string  `json:"name" binding:"required"`
	Website     *string `json:"website"`
	Description *string `json:"description"`
}

type BrandResponse struct {
	ID            int64   `json:"id"`
	Name          string  `json:"name"`
	Website       *string `json:"website"`
	Description   *string `json:"description"`
	Status        string  `json:"status"`
	KeywordCount  int     `json:"keyword_count"`
	QuestionCount int     `json:"question_count"`
	CreatedAt     string  `json:"created_at"`
	UpdatedAt     string  `json:"updated_at"`
}

type BrandLibrarySummaryResponse struct {
	PlanCode               string `json:"plan_code"`
	PlanName               string `json:"plan_name"`
	MaxBrands              int    `json:"max_brands"`
	UsedBrands             int    `json:"used_brands"`
	RemainingBrands        int    `json:"remaining_brands"`
	MaxKeywords            int    `json:"max_keywords"`
	UsedKeywords           int    `json:"used_keywords"`
	RemainingKeywords      int    `json:"remaining_keywords"`
	MaxQuestionsPerKeyword int    `json:"max_questions_per_keyword"`
}

func (s *BrandService) List(ctx context.Context) ([]BrandResponse, error) {
	actor := auth.MustActor(ctx)
	return sharedcache.LoadJSON(ctx, s.cache, &s.cacheGroup, brandListCacheKey(actor.TenantID), defaultCacheTTL(), func(loadCtx context.Context) ([]BrandResponse, error) {
		return s.loadBrands(loadCtx, actor.TenantID)
	})
}

func (s *BrandService) Summary(ctx context.Context) (*BrandLibrarySummaryResponse, error) {
	actor := auth.MustActor(ctx)
	return sharedcache.LoadJSON(ctx, s.cache, &s.cacheGroup, brandLibrarySummaryCacheKey(actor.TenantID), defaultCacheTTL(), func(loadCtx context.Context) (*BrandLibrarySummaryResponse, error) {
		return s.loadBrandLibrarySummary(loadCtx, actor.TenantID)
	})
}

func (s *BrandService) Create(ctx context.Context, req BrandRequest) (*BrandResponse, error) {
	actor := auth.MustActor(ctx)
	normalizeBrandRequest(&req)
	if req.Name == "" {
		return nil, response.ErrBadRequest(40001, "invalid_params", "name is required")
	}

	summary, err := s.loadBrandLibrarySummary(ctx, actor.TenantID)
	if err != nil {
		return nil, err
	}

	var id int64
	var ca interface{}
	err = s.pool.QueryRow(ctx, `
		WITH usage AS (
			SELECT COUNT(*)::INT AS used_brands
			FROM brands
			WHERE tenant_id = $1 AND deleted_at IS NULL
		)
		INSERT INTO brands (tenant_id, name, website, description, status)
		SELECT $1, $2, $3, $4, 'active'
		FROM usage
		WHERE usage.used_brands < $5
		RETURNING id, created_at
	`, actor.TenantID, req.Name, req.Website, req.Description, summary.MaxBrands).Scan(&id, &ca)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, response.ErrConflict(40904, "brand_limit_reached", fmt.Sprintf("current plan allows up to %d brand companies", summary.MaxBrands))
		}
		if isUniqueConstraintError(err, "uk_brand_tenant_name_active") {
			return nil, response.ErrConflict(40901, "brand_exists", "brand with this name already exists")
		}
		return nil, response.ErrInternal(50010, "create_failed", "failed to create brand")
	}

	afterJSON, _ := json.Marshal(map[string]interface{}{"id": id, "name": req.Name})
	result := "success"
	resourceType := "brand"
	requestID := middleware.RequestIDFromContext(ctx)
	s.auditLogs.Log(auditlog.Entry{
		OperatorID:   actor.UserID,
		TenantID:     &actor.TenantID,
		Module:       "brand",
		Action:       "create",
		ResourceType: &resourceType,
		ResourceID:   &id,
		RequestID:    nilIfEmptyString(requestID),
		AfterJSON:    afterJSON,
		Result:       &result,
	})

	invalidateBrandCaches(ctx, s.cache, actor.TenantID, id)
	return &BrandResponse{
		ID:            id,
		Name:          req.Name,
		Website:       req.Website,
		Description:   req.Description,
		Status:        "active",
		KeywordCount:  0,
		QuestionCount: 0,
		CreatedAt:     fmt.Sprintf("%v", ca),
	}, nil
}

func (s *BrandService) Detail(ctx context.Context, id int64) (*BrandResponse, error) {
	actor := auth.MustActor(ctx)
	record, found, err := sharedcache.LoadJSONWithEmpty(ctx, s.cache, &s.cacheGroup, brandDetailCacheKey(actor.TenantID, id), defaultCacheTTL(), defaultCacheEmptyTTL(), func(loadCtx context.Context) (*BrandResponse, bool, error) {
		return s.loadBrandDetail(loadCtx, actor.TenantID, id)
	})
	if err != nil {
		return nil, err
	}
	if !found || record == nil {
		return nil, response.ErrNotFound(40420, "brand_not_found", "brand not found")
	}
	return record, nil
}

func (s *BrandService) Update(ctx context.Context, id int64, req BrandRequest) error {
	actor := auth.MustActor(ctx)
	normalizeBrandRequest(&req)
	if req.Name == "" {
		return response.ErrBadRequest(40001, "invalid_params", "name is required")
	}
	tag, err := s.pool.Exec(ctx, `
		UPDATE brands SET name = $1, website = $2, description = $3, updated_at = NOW()
		WHERE id = $4 AND tenant_id = $5 AND deleted_at IS NULL
	`, req.Name, req.Website, req.Description, id, actor.TenantID)
	if err != nil {
		if isUniqueConstraintError(err, "uk_brand_tenant_name_active") {
			return response.ErrConflict(40901, "brand_exists", "brand with this name already exists")
		}
		return response.ErrInternal(50010, "update_failed", "failed to update brand")
	}
	if tag.RowsAffected() == 0 {
		return response.ErrNotFound(40420, "brand_not_found", "brand not found")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, id)
	return nil
}

func normalizeBrandRequest(req *BrandRequest) {
	req.Name = strings.TrimSpace(req.Name)
	req.Website = normalizeOptionalString(req.Website)
	req.Description = normalizeOptionalString(req.Description)
}

func normalizeOptionalString(value *string) *string {
	if value == nil {
		return nil
	}
	return nilIfEmptyString(*value)
}

func (s *BrandService) Delete(ctx context.Context, id int64) error {
	actor := auth.MustActor(ctx)
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return fmt.Errorf("begin tx: %w", err)
	}
	defer func() {
		_ = tx.Rollback(ctx)
	}()

	tag, err := tx.Exec(ctx, `UPDATE brands SET deleted_at = NOW(), updated_at = NOW() WHERE id = $1 AND tenant_id = $2 AND deleted_at IS NULL`, id, actor.TenantID)
	if err != nil || tag.RowsAffected() == 0 {
		return response.ErrNotFound(40420, "brand_not_found", "brand not found")
	}
	_, _ = tx.Exec(ctx, `UPDATE brand_keywords SET deleted_at = NOW(), updated_at = NOW() WHERE brand_id = $1 AND tenant_id = $2 AND deleted_at IS NULL`, id, actor.TenantID)
	_, _ = tx.Exec(ctx, `UPDATE brand_questions SET deleted_at = NOW(), updated_at = NOW() WHERE brand_id = $1 AND tenant_id = $2 AND deleted_at IS NULL`, id, actor.TenantID)
	_, _ = tx.Exec(ctx, `UPDATE competitors SET deleted_at = NOW(), updated_at = NOW() WHERE brand_id = $1 AND tenant_id = $2 AND deleted_at IS NULL`, id, actor.TenantID)

	if err := s.cleanupMonitoringAfterBrandDelete(ctx, actor.TenantID, id); err != nil {
		return err
	}

	afterJSON, _ := json.Marshal(map[string]interface{}{"id": id, "action": "cascade_soft_delete"})
	if err := tx.Commit(ctx); err != nil {
		return err
	}

	result := "success"
	resourceType := "brand"
	requestID := middleware.RequestIDFromContext(ctx)
	s.auditLogs.Log(auditlog.Entry{
		OperatorID:   actor.UserID,
		TenantID:     &actor.TenantID,
		Module:       "brand",
		Action:       "delete",
		ResourceType: &resourceType,
		ResourceID:   &id,
		RequestID:    nilIfEmptyString(requestID),
		AfterJSON:    afterJSON,
		Result:       &result,
	})

	invalidateBrandCaches(ctx, s.cache, actor.TenantID, id)
	return nil
}

// --- Keyword CRUD ---

type KeywordRequest struct {
	Name string `json:"name" binding:"required"`
}

type KeywordResponse struct {
	ID        int64  `json:"id"`
	BrandID   int64  `json:"brand_id"`
	Name      string `json:"name"`
	Status    string `json:"status"`
	CreatedAt string `json:"created_at"`
}

func (s *BrandService) ListKeywords(ctx context.Context, brandID int64) ([]KeywordResponse, error) {
	actor := auth.MustActor(ctx)
	return sharedcache.LoadJSON(ctx, s.cache, &s.cacheGroup, brandKeywordsCacheKey(actor.TenantID, brandID), defaultCacheTTL(), func(loadCtx context.Context) ([]KeywordResponse, error) {
		return s.loadBrandKeywords(loadCtx, actor.TenantID, brandID)
	})
}

func (s *BrandService) CreateKeyword(ctx context.Context, brandID int64, req KeywordRequest) (*KeywordResponse, error) {
	actor := auth.MustActor(ctx)
	req.Name = strings.TrimSpace(req.Name)
	if req.Name == "" {
		return nil, response.ErrBadRequest(40001, "invalid_params", "name is required")
	}
	exists, err := s.brandExists(ctx, actor.TenantID, brandID)
	if err != nil {
		return nil, err
	}
	if !exists {
		return nil, response.ErrNotFound(40420, "brand_not_found", "brand not found")
	}

	summary, err := s.loadBrandLibrarySummary(ctx, actor.TenantID)
	if err != nil {
		return nil, err
	}

	var id int64
	var ca interface{}
	err = s.pool.QueryRow(ctx, `
		WITH usage AS (
			SELECT COUNT(*)::INT AS used_keywords
			FROM brand_keywords
			WHERE tenant_id = $1 AND deleted_at IS NULL
		)
		INSERT INTO brand_keywords (tenant_id, brand_id, name, status)
		SELECT $1, $2, $3, 'active'
		FROM usage
		WHERE usage.used_keywords < $4
		RETURNING id, created_at
	`, actor.TenantID, brandID, req.Name, summary.MaxKeywords).Scan(&id, &ca)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, response.ErrConflict(40905, "keyword_limit_reached", fmt.Sprintf("current plan allows up to %d keywords", summary.MaxKeywords))
		}
		if isUniqueConstraintError(err, "uk_brand_keyword_name_active") {
			return nil, response.ErrConflict(40902, "keyword_exists", "keyword with this name already exists for this brand")
		}
		if isForeignKeyConstraintError(err) {
			return nil, response.ErrNotFound(40420, "brand_not_found", "brand not found")
		}
		return nil, response.ErrInternal(50010, "create_failed", "failed to create keyword")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return &KeywordResponse{ID: id, BrandID: brandID, Name: req.Name, Status: "active", CreatedAt: fmt.Sprintf("%v", ca)}, nil
}

func (s *BrandService) UpdateKeyword(ctx context.Context, brandID, keywordID int64, req KeywordRequest) error {
	actor := auth.MustActor(ctx)
	req.Name = strings.TrimSpace(req.Name)
	if req.Name == "" {
		return response.ErrBadRequest(40001, "invalid_params", "name is required")
	}
	tag, err := s.pool.Exec(ctx, `
		UPDATE brand_keywords SET name = $1, updated_at = NOW()
		WHERE id = $2 AND brand_id = $3 AND tenant_id = $4 AND deleted_at IS NULL
	`, req.Name, keywordID, brandID, actor.TenantID)
	if err != nil {
		if isUniqueConstraintError(err, "uk_brand_keyword_name_active") {
			return response.ErrConflict(40902, "keyword_exists", "keyword with this name already exists for this brand")
		}
		return response.ErrInternal(50010, "update_failed", "failed to update keyword")
	}
	if tag.RowsAffected() == 0 {
		return response.ErrNotFound(40421, "keyword_not_found", "keyword not found")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return nil
}

func (s *BrandService) DeleteKeyword(ctx context.Context, brandID, keywordID int64) error {
	actor := auth.MustActor(ctx)
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return fmt.Errorf("begin tx: %w", err)
	}
	defer func() {
		_ = tx.Rollback(ctx)
	}()

	questionRows, err := tx.Query(ctx, `
		SELECT id
		FROM brand_questions
		WHERE brand_id = $1
		  AND keyword_id = $2
		  AND tenant_id = $3
		  AND deleted_at IS NULL
	`, brandID, keywordID, actor.TenantID)
	if err != nil {
		return response.ErrInternal(50010, "query_failed", "failed to load keyword questions")
	}
	questionIDs := make([]int64, 0)
	for questionRows.Next() {
		var questionID int64
		if scanErr := questionRows.Scan(&questionID); scanErr != nil {
			return response.ErrInternal(50010, "scan_failed", scanErr.Error())
		}
		questionIDs = append(questionIDs, questionID)
	}
	if err := questionRows.Err(); err != nil {
		return response.ErrInternal(50010, "scan_failed", err.Error())
	}
	questionRows.Close()

	tag, err := tx.Exec(ctx, `
		UPDATE brand_keywords SET deleted_at = NOW(), updated_at = NOW()
		WHERE id = $1 AND brand_id = $2 AND tenant_id = $3 AND deleted_at IS NULL
	`, keywordID, brandID, actor.TenantID)
	if err != nil || tag.RowsAffected() == 0 {
		return response.ErrNotFound(40421, "keyword_not_found", "keyword not found")
	}

	if _, err := tx.Exec(ctx, `
		UPDATE brand_questions
		SET deleted_at = NOW(), updated_at = NOW()
		WHERE brand_id = $1
		  AND keyword_id = $2
		  AND tenant_id = $3
		  AND deleted_at IS NULL
	`, brandID, keywordID, actor.TenantID); err != nil {
		return response.ErrInternal(50010, "update_failed", "failed to soft delete questions under keyword")
	}

	if err := s.cleanupMonitoringAfterKeywordDelete(ctx, actor.TenantID, brandID, keywordID, questionIDs); err != nil {
		return err
	}

	if err := tx.Commit(ctx); err != nil {
		return err
	}

	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return nil
}

// --- Question CRUD ---

type QuestionRequest struct {
	KeywordID    int64  `json:"keyword_id" binding:"required"`
	QuestionText string `json:"question_text" binding:"required"`
}

type QuestionResponse struct {
	ID           int64  `json:"id"`
	BrandID      int64  `json:"brand_id"`
	KeywordID    int64  `json:"keyword_id"`
	QuestionText string `json:"question_text"`
	Status       string `json:"status"`
	CreatedAt    string `json:"created_at"`
}

func (s *BrandService) ListQuestions(ctx context.Context, brandID int64, keywordID *int64) ([]QuestionResponse, error) {
	actor := auth.MustActor(ctx)
	return sharedcache.LoadJSON(ctx, s.cache, &s.cacheGroup, brandQuestionsCacheKey(actor.TenantID, brandID, keywordID), defaultCacheTTL(), func(loadCtx context.Context) ([]QuestionResponse, error) {
		return s.loadBrandQuestions(loadCtx, actor.TenantID, brandID, keywordID)
	})
}

func (s *BrandService) CreateQuestion(ctx context.Context, brandID int64, req QuestionRequest) (*QuestionResponse, error) {
	actor := auth.MustActor(ctx)
	if req.KeywordID <= 0 {
		return nil, response.ErrBadRequest(40001, "invalid_params", "keyword_id is required")
	}
	req.QuestionText = strings.TrimSpace(req.QuestionText)
	if req.QuestionText == "" {
		return nil, response.ErrBadRequest(40001, "invalid_params", "question_text is required")
	}

	exists, err := s.keywordExistsForBrand(ctx, actor.TenantID, brandID, req.KeywordID)
	if err != nil {
		return nil, err
	}
	if !exists {
		return nil, response.ErrNotFound(40421, "keyword_not_found", "keyword not found")
	}

	summary, err := s.loadBrandLibrarySummary(ctx, actor.TenantID)
	if err != nil {
		return nil, err
	}

	var questionID int64
	var ca interface{}
	err = s.pool.QueryRow(ctx, `
		WITH usage AS (
			SELECT COUNT(*)::INT AS used_questions
			FROM brand_questions
			WHERE tenant_id = $1 AND keyword_id = $3 AND deleted_at IS NULL
		)
		INSERT INTO brand_questions (tenant_id, brand_id, keyword_id, question_text, status)
		SELECT $1, $2, $3, $4, 'active'
		FROM usage
		WHERE usage.used_questions < $5
		RETURNING id, created_at
	`, actor.TenantID, brandID, req.KeywordID, req.QuestionText, summary.MaxQuestionsPerKeyword).Scan(&questionID, &ca)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, response.ErrConflict(40906, "question_limit_reached", fmt.Sprintf("each keyword allows up to %d questions", summary.MaxQuestionsPerKeyword))
		}
		if isForeignKeyConstraintError(err) {
			return nil, response.ErrNotFound(40421, "keyword_not_found", "keyword not found")
		}
		return nil, response.ErrInternal(50010, "create_failed", "failed to create question")
	}

	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return &QuestionResponse{
		ID:           questionID,
		BrandID:      brandID,
		KeywordID:    req.KeywordID,
		QuestionText: req.QuestionText,
		Status:       "active",
		CreatedAt:    fmt.Sprintf("%v", ca),
	}, nil
}

type UpdateQuestionRequest struct {
	QuestionText string `json:"question_text" binding:"required"`
}

func (s *BrandService) UpdateQuestion(ctx context.Context, brandID, questionID int64, req UpdateQuestionRequest) error {
	actor := auth.MustActor(ctx)
	req.QuestionText = strings.TrimSpace(req.QuestionText)
	if req.QuestionText == "" {
		return response.ErrBadRequest(40001, "invalid_params", "question_text is required")
	}

	tag, err := s.pool.Exec(ctx, `
		UPDATE brand_questions SET question_text = $1, updated_at = NOW()
		WHERE id = $2 AND brand_id = $3 AND tenant_id = $4 AND deleted_at IS NULL
	`, req.QuestionText, questionID, brandID, actor.TenantID)
	if err != nil || tag.RowsAffected() == 0 {
		return response.ErrNotFound(40422, "question_not_found", "question not found")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return nil
}

func (s *BrandService) DeleteQuestion(ctx context.Context, brandID, questionID int64) error {
	actor := auth.MustActor(ctx)
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return fmt.Errorf("begin tx: %w", err)
	}
	defer func() {
		_ = tx.Rollback(ctx)
	}()

	tag, err := tx.Exec(ctx, `
		UPDATE brand_questions SET deleted_at = NOW(), updated_at = NOW()
		WHERE id = $1 AND brand_id = $2 AND tenant_id = $3 AND deleted_at IS NULL
	`, questionID, brandID, actor.TenantID)
	if err != nil || tag.RowsAffected() == 0 {
		return response.ErrNotFound(40422, "question_not_found", "question not found")
	}

	if err := s.cleanupMonitoringAfterQuestionDelete(ctx, actor.TenantID, brandID, questionID); err != nil {
		return err
	}

	if err := tx.Commit(ctx); err != nil {
		return err
	}

	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return nil
}

// --- Competitor CRUD ---

type CompetitorRequest struct {
	Name             string           `json:"name" binding:"required"`
	Website          *string          `json:"website"`
	Description      *string          `json:"description"`
	ProductLinesJSON *json.RawMessage `json:"product_lines_json"`
}

type CompetitorResponse struct {
	ID               int64            `json:"id"`
	BrandID          int64            `json:"brand_id"`
	Name             string           `json:"name"`
	Website          *string          `json:"website"`
	Description      *string          `json:"description"`
	ProductLinesJSON *json.RawMessage `json:"product_lines_json"`
	CreatedAt        string           `json:"created_at"`
}

func (s *BrandService) ListCompetitors(ctx context.Context, brandID int64) ([]CompetitorResponse, error) {
	actor := auth.MustActor(ctx)
	return sharedcache.LoadJSON(ctx, s.cache, &s.cacheGroup, brandCompetitorsCacheKey(actor.TenantID, brandID), defaultCacheTTL(), func(loadCtx context.Context) ([]CompetitorResponse, error) {
		return s.loadBrandCompetitors(loadCtx, actor.TenantID, brandID)
	})
}

func (s *BrandService) CreateCompetitor(ctx context.Context, brandID int64, req CompetitorRequest) (*CompetitorResponse, error) {
	actor := auth.MustActor(ctx)
	var plJSON []byte
	if req.ProductLinesJSON != nil {
		plJSON = *req.ProductLinesJSON
	}

	var id int64
	var ca interface{}
	err := s.pool.QueryRow(ctx, `
		INSERT INTO competitors (tenant_id, brand_id, name, website, description, product_lines_json)
		VALUES ($1, $2, $3, $4, $5, $6) RETURNING id, created_at
	`, actor.TenantID, brandID, req.Name, req.Website, req.Description, plJSON).Scan(&id, &ca)
	if err != nil {
		return nil, response.ErrInternal(50010, "create_failed", "failed to create competitor")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return &CompetitorResponse{ID: id, BrandID: brandID, Name: req.Name, Website: req.Website, Description: req.Description, ProductLinesJSON: req.ProductLinesJSON, CreatedAt: fmt.Sprintf("%v", ca)}, nil
}

func (s *BrandService) UpdateCompetitor(ctx context.Context, brandID, competitorID int64, req CompetitorRequest) error {
	actor := auth.MustActor(ctx)
	var plJSON []byte
	if req.ProductLinesJSON != nil {
		plJSON = *req.ProductLinesJSON
	}
	tag, err := s.pool.Exec(ctx, `
		UPDATE competitors SET name = $1, website = $2, description = $3, product_lines_json = $4, updated_at = NOW()
		WHERE id = $5 AND brand_id = $6 AND tenant_id = $7 AND deleted_at IS NULL
	`, req.Name, req.Website, req.Description, plJSON, competitorID, brandID, actor.TenantID)
	if err != nil || tag.RowsAffected() == 0 {
		return response.ErrNotFound(40423, "competitor_not_found", "competitor not found")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return nil
}

func (s *BrandService) DeleteCompetitor(ctx context.Context, brandID, competitorID int64) error {
	actor := auth.MustActor(ctx)
	tag, err := s.pool.Exec(ctx, `
		UPDATE competitors SET deleted_at = NOW(), updated_at = NOW()
		WHERE id = $1 AND brand_id = $2 AND tenant_id = $3 AND deleted_at IS NULL
	`, competitorID, brandID, actor.TenantID)
	if err != nil || tag.RowsAffected() == 0 {
		return response.ErrNotFound(40423, "competitor_not_found", "competitor not found")
	}
	invalidateBrandCaches(ctx, s.cache, actor.TenantID, brandID)
	return nil
}

func (s *BrandService) loadBrands(ctx context.Context, tenantID int64) ([]BrandResponse, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT
			b.id,
			b.name,
			b.website,
			b.description,
			b.status,
			COALESCE(stats.keyword_count, 0) AS keyword_count,
			COALESCE(stats.question_count, 0) AS question_count,
			b.created_at,
			b.updated_at
		FROM brands b
		LEFT JOIN LATERAL (
			SELECT
				COUNT(DISTINCT k.id)::INT AS keyword_count,
				COUNT(q.id)::INT AS question_count
			FROM brand_keywords k
			LEFT JOIN brand_questions q
				ON q.keyword_id = k.id
			   AND q.tenant_id = b.tenant_id
			   AND q.deleted_at IS NULL
			WHERE k.brand_id = b.id
			  AND k.tenant_id = b.tenant_id
			  AND k.deleted_at IS NULL
		) stats ON true
		WHERE b.tenant_id = $1 AND b.deleted_at IS NULL
		ORDER BY b.created_at DESC
	`, tenantID)
	if err != nil {
		return nil, response.ErrInternal(50010, "query_failed", "failed to list brands")
	}
	defer rows.Close()

	brands := make([]BrandResponse, 0)
	for rows.Next() {
		var item BrandResponse
		var createdAt interface{}
		var updatedAt interface{}
		if err := rows.Scan(&item.ID, &item.Name, &item.Website, &item.Description, &item.Status, &item.KeywordCount, &item.QuestionCount, &createdAt, &updatedAt); err != nil {
			return nil, response.ErrInternal(50010, "scan_failed", err.Error())
		}
		item.CreatedAt = fmt.Sprintf("%v", createdAt)
		item.UpdatedAt = fmt.Sprintf("%v", updatedAt)
		brands = append(brands, item)
	}
	return brands, nil
}

func (s *BrandService) loadBrandDetail(ctx context.Context, tenantID, brandID int64) (*BrandResponse, bool, error) {
	var item BrandResponse
	var createdAt interface{}
	var updatedAt interface{}
	err := s.pool.QueryRow(ctx, `
		SELECT
			b.id,
			b.name,
			b.website,
			b.description,
			b.status,
			COALESCE(stats.keyword_count, 0) AS keyword_count,
			COALESCE(stats.question_count, 0) AS question_count,
			b.created_at,
			b.updated_at
		FROM brands b
		LEFT JOIN LATERAL (
			SELECT
				COUNT(DISTINCT k.id)::INT AS keyword_count,
				COUNT(q.id)::INT AS question_count
			FROM brand_keywords k
			LEFT JOIN brand_questions q
				ON q.keyword_id = k.id
			   AND q.tenant_id = b.tenant_id
			   AND q.deleted_at IS NULL
			WHERE k.brand_id = b.id
			  AND k.tenant_id = b.tenant_id
			  AND k.deleted_at IS NULL
		) stats ON true
		WHERE b.id = $1 AND b.tenant_id = $2 AND b.deleted_at IS NULL
	`, brandID, tenantID).Scan(&item.ID, &item.Name, &item.Website, &item.Description, &item.Status, &item.KeywordCount, &item.QuestionCount, &createdAt, &updatedAt)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, false, nil
		}
		return nil, false, response.ErrInternal(50010, "query_failed", "failed to fetch brand")
	}
	item.CreatedAt = fmt.Sprintf("%v", createdAt)
	item.UpdatedAt = fmt.Sprintf("%v", updatedAt)
	return &item, true, nil
}

func (s *BrandService) loadBrandKeywords(ctx context.Context, tenantID, brandID int64) ([]KeywordResponse, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, brand_id, name, status, created_at FROM brand_keywords
		WHERE brand_id = $1 AND tenant_id = $2 AND deleted_at IS NULL ORDER BY created_at DESC
	`, brandID, tenantID)
	if err != nil {
		return nil, response.ErrInternal(50010, "query_failed", "failed to list keywords")
	}
	defer rows.Close()

	items := make([]KeywordResponse, 0)
	for rows.Next() {
		var item KeywordResponse
		var createdAt interface{}
		if err := rows.Scan(&item.ID, &item.BrandID, &item.Name, &item.Status, &createdAt); err != nil {
			return nil, response.ErrInternal(50010, "scan_failed", err.Error())
		}
		item.CreatedAt = fmt.Sprintf("%v", createdAt)
		items = append(items, item)
	}
	return items, nil
}

func (s *BrandService) loadBrandQuestions(ctx context.Context, tenantID, brandID int64, keywordID *int64) ([]QuestionResponse, error) {
	query := `
		SELECT q.id, q.brand_id, q.keyword_id, q.question_text, q.status, q.created_at
		FROM brand_questions q
		WHERE q.brand_id = $1 AND q.tenant_id = $2 AND q.deleted_at IS NULL`
	args := []interface{}{brandID, tenantID}

	if keywordID != nil {
		query += ` AND q.keyword_id = $3`
		args = append(args, *keywordID)
	}
	query += ` ORDER BY q.created_at DESC`

	rows, err := s.pool.Query(ctx, query, args...)
	if err != nil {
		return nil, response.ErrInternal(50010, "query_failed", "failed to list questions")
	}
	defer rows.Close()

	items := make([]QuestionResponse, 0)
	for rows.Next() {
		var item QuestionResponse
		var createdAt interface{}
		if err := rows.Scan(&item.ID, &item.BrandID, &item.KeywordID, &item.QuestionText, &item.Status, &createdAt); err != nil {
			return nil, response.ErrInternal(50010, "scan_failed", err.Error())
		}
		item.CreatedAt = fmt.Sprintf("%v", createdAt)
		items = append(items, item)
	}
	return items, nil
}

func (s *BrandService) loadBrandCompetitors(ctx context.Context, tenantID, brandID int64) ([]CompetitorResponse, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, brand_id, name, website, description, product_lines_json, created_at
		FROM competitors WHERE brand_id = $1 AND tenant_id = $2 AND deleted_at IS NULL ORDER BY created_at DESC
	`, brandID, tenantID)
	if err != nil {
		return nil, response.ErrInternal(50010, "query_failed", "failed to list competitors")
	}
	defer rows.Close()

	items := make([]CompetitorResponse, 0)
	for rows.Next() {
		var item CompetitorResponse
		var createdAt interface{}
		var productLinesJSON []byte
		if err := rows.Scan(&item.ID, &item.BrandID, &item.Name, &item.Website, &item.Description, &productLinesJSON, &createdAt); err != nil {
			return nil, response.ErrInternal(50010, "scan_failed", err.Error())
		}
		item.CreatedAt = fmt.Sprintf("%v", createdAt)
		if productLinesJSON != nil {
			raw := json.RawMessage(productLinesJSON)
			item.ProductLinesJSON = &raw
		}
		items = append(items, item)
	}
	return items, nil
}

type brandLibraryPlan struct {
	PlanCode  string
	PlanName  string
	MaxBrands int
}

type brandLibraryUsage struct {
	BrandCount   int
	KeywordCount int
}

func (s *BrandService) loadBrandLibrarySummary(ctx context.Context, tenantID int64) (*BrandLibrarySummaryResponse, error) {
	plan, err := s.loadBrandLibraryPlan(ctx, tenantID)
	if err != nil {
		return nil, err
	}

	usage, err := s.loadBrandLibraryUsage(ctx, tenantID)
	if err != nil {
		return nil, err
	}

	maxBrands := s.limits.BrandLimitForPlan(plan.PlanCode)
	if plan.MaxBrands > 0 {
		maxBrands = plan.MaxBrands
	}
	maxKeywords := s.limits.MaxKeywords

	return &BrandLibrarySummaryResponse{
		PlanCode:               plan.PlanCode,
		PlanName:               plan.PlanName,
		MaxBrands:              maxBrands,
		UsedBrands:             usage.BrandCount,
		RemainingBrands:        maxInt(maxBrands-usage.BrandCount, 0),
		MaxKeywords:            maxKeywords,
		UsedKeywords:           usage.KeywordCount,
		RemainingKeywords:      maxInt(maxKeywords-usage.KeywordCount, 0),
		MaxQuestionsPerKeyword: s.limits.MaxQuestionsPerKeyword,
	}, nil
}

func (s *BrandService) loadBrandLibraryPlan(ctx context.Context, tenantID int64) (*brandLibraryPlan, error) {
	plan := &brandLibraryPlan{
		PlanCode:  "free",
		PlanName:  "",
		MaxBrands: s.limits.BrandLimitForPlan("free"),
	}

	var quotaPolicyJSON []byte
	err := s.pool.QueryRow(ctx, `
		SELECT p.plan_code, p.name, p.quota_policy_json
		FROM tenant_plan_subscriptions s
		JOIN plans p ON p.id = s.plan_id
		WHERE s.tenant_id = $1
		  AND s.status = 'active'
		  AND s.deleted_at IS NULL
		  AND p.status = 'active'
		  AND s.end_at > $2
		ORDER BY s.start_at DESC
		LIMIT 1
	`, tenantID, time.Now().UTC()).Scan(&plan.PlanCode, &plan.PlanName, &quotaPolicyJSON)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return plan, nil
		}
		return nil, response.ErrInternal(50010, "query_failed", "failed to load active plan")
	}
	var quotaPolicy struct {
		BrandLimit int `json:"brand_limit"`
	}
	if len(quotaPolicyJSON) > 0 {
		_ = json.Unmarshal(quotaPolicyJSON, &quotaPolicy)
	}
	if quotaPolicy.BrandLimit > 0 {
		plan.MaxBrands = quotaPolicy.BrandLimit
	}
	return plan, nil
}

func (s *BrandService) loadBrandLibraryUsage(ctx context.Context, tenantID int64) (*brandLibraryUsage, error) {
	usage := &brandLibraryUsage{}
	err := s.pool.QueryRow(ctx, `
		SELECT
			(SELECT COUNT(*)::INT FROM brands WHERE tenant_id = $1 AND deleted_at IS NULL) AS brand_count,
			(SELECT COUNT(*)::INT FROM brand_keywords WHERE tenant_id = $1 AND deleted_at IS NULL) AS keyword_count
	`, tenantID).Scan(&usage.BrandCount, &usage.KeywordCount)
	if err != nil {
		return nil, response.ErrInternal(50010, "query_failed", "failed to load brand library usage")
	}
	return usage, nil
}

func (s *BrandService) brandExists(ctx context.Context, tenantID, brandID int64) (bool, error) {
	var exists bool
	err := s.pool.QueryRow(ctx, `
		SELECT EXISTS (
			SELECT 1
			FROM brands
			WHERE id = $1 AND tenant_id = $2 AND deleted_at IS NULL
		)
	`, brandID, tenantID).Scan(&exists)
	if err != nil {
		return false, response.ErrInternal(50010, "query_failed", "failed to load brand")
	}
	return exists, nil
}

func (s *BrandService) keywordExistsForBrand(ctx context.Context, tenantID, brandID, keywordID int64) (bool, error) {
	var exists bool
	err := s.pool.QueryRow(ctx, `
		SELECT EXISTS (
			SELECT 1
			FROM brand_keywords
			WHERE id = $1
			  AND brand_id = $2
			  AND tenant_id = $3
			  AND deleted_at IS NULL
		)
	`, keywordID, brandID, tenantID).Scan(&exists)
	if err != nil {
		return false, response.ErrInternal(50010, "query_failed", "failed to load keyword")
	}
	return exists, nil
}

func isUniqueConstraintError(err error, constraint string) bool {
	var pgErr *pgconn.PgError
	return errors.As(err, &pgErr) && pgErr.Code == "23505" && pgErr.ConstraintName == constraint
}

func isForeignKeyConstraintError(err error) bool {
	var pgErr *pgconn.PgError
	return errors.As(err, &pgErr) && pgErr.Code == "23503"
}

func maxInt(value, floor int) int {
	if value < floor {
		return floor
	}
	return value
}