package api

import (
	"encoding/json"
	"fmt"
	"net/http"
	"regexp"
	"sort"
	"strings"
	"time"

	"asset-tracker/internal/auth"
	"asset-tracker/internal/model"

	"github.com/gin-gonic/gin"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

type Handler struct {
	db *gorm.DB
	tm *auth.TokenManager
}

func NewHandler(db *gorm.DB, tm *auth.TokenManager) *Handler {
	return &Handler{db: db, tm: tm}
}

func toJSON(v any) string {
	b, err := json.Marshal(v)
	if err != nil {
		return "{}"
	}
	return string(b)
}

func (h *Handler) writeAudit(userID uint, entityType string, entityID uint, action string, before any, after any) {
	log := model.AuditLog{
		UserID:     userID,
		EntityType: entityType,
		EntityID:   entityID,
		Action:     action,
		BeforeJSON: toJSON(before),
		AfterJSON:  toJSON(after),
	}
	_ = h.db.Create(&log).Error
}

var currencyPattern = regexp.MustCompile(`^[A-Z]{3,10}$`)

type loginRequest struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

func (h *Handler) Login(c *gin.Context) {
	var req loginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		bizError(c, "auth", "login", "BAD_REQUEST", err, nil)
		JSONBadRequest(c, "BAD_REQUEST", "invalid request", err.Error())
		return
	}

	var user model.User
	if err := h.db.Where("username = ?", strings.TrimSpace(req.Username)).First(&user).Error; err != nil {
		bizError(c, "auth", "login", "AUTH_INVALID_CREDENTIALS", err, map[string]any{"username": strings.TrimSpace(req.Username)})
		JSONUnauthorized(c, "AUTH_INVALID_CREDENTIALS", "invalid username or password")
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(req.Password)); err != nil {
		bizError(c, "auth", "login", "AUTH_INVALID_CREDENTIALS", err, map[string]any{"username": user.Username, "uid": user.ID})
		JSONUnauthorized(c, "AUTH_INVALID_CREDENTIALS", "invalid username or password")
		return
	}

	access, err := h.tm.GenerateAccessToken(user.ID, user.Username, user.Timezone)
	if err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	refresh, jti, exp, err := h.tm.GenerateRefreshToken(user.ID, user.Username, user.Timezone)
	if err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	if err := h.db.Create(&model.RefreshSession{UserID: user.ID, JTI: jti, ExpiresAt: exp}).Error; err != nil {
		bizError(c, "auth", "login", "REFRESH_SESSION_CREATE_FAILED", err, map[string]any{"uid": user.ID})
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	secure := strings.EqualFold(strings.TrimSpace(c.GetHeader("X-Forwarded-Proto")), "https") || c.Request.TLS != nil
	c.SetSameSite(http.SameSiteLaxMode)
	c.SetCookie("refresh_token", refresh, h.tm.RefreshMaxAgeSeconds(), "/api/v1/auth/refresh", "", secure, true)

	bizInfo(c, "auth", "login", map[string]any{"uid": user.ID, "username": user.Username})
	c.JSON(http.StatusOK, gin.H{
		"access_token": access,
		"token_type":   "Bearer",
	})
}

type refreshRequest struct {
	RefreshToken string `json:"refresh_token" binding:"required"`
}

func (h *Handler) Refresh(c *gin.Context) {
	refreshToken := strings.TrimSpace(c.GetHeader("X-Refresh-Token"))
	if refreshToken == "" {
		if cookie, err := c.Cookie("refresh_token"); err == nil {
			refreshToken = strings.TrimSpace(cookie)
		}
	}
	if refreshToken == "" {
		var req refreshRequest
		if err := c.ShouldBindJSON(&req); err == nil {
			refreshToken = strings.TrimSpace(req.RefreshToken)
		}
	}
	if refreshToken == "" {
		bizError(c, "auth", "refresh", "AUTH_MISSING_REFRESH", nil, nil)
		JSONUnauthorized(c, "AUTH_MISSING_REFRESH", "missing refresh token")
		return
	}

	claims, err := h.tm.ParseAndValidate(refreshToken, "refresh")
	if err != nil {
		JSONUnauthorized(c, "AUTH_INVALID_REFRESH", "invalid refresh token")
		return
	}
	if strings.TrimSpace(claims.ID) == "" {
		JSONUnauthorized(c, "AUTH_INVALID_REFRESH", "invalid refresh token")
		return
	}

	var session model.RefreshSession
	if err := h.db.Where("jti = ? AND user_id = ?", claims.ID, claims.UserID).First(&session).Error; err != nil {
		bizError(c, "auth", "refresh", "AUTH_INVALID_REFRESH", err, map[string]any{"uid": claims.UserID, "jti": claims.ID})
		JSONUnauthorized(c, "AUTH_INVALID_REFRESH", "invalid refresh token")
		return
	}
	if session.RevokedAt != nil || session.ExpiresAt.Before(time.Now().UTC()) {
		bizError(c, "auth", "refresh", "AUTH_INVALID_REFRESH", nil, map[string]any{"uid": claims.UserID, "jti": claims.ID, "revoked": session.RevokedAt != nil})
		JSONUnauthorized(c, "AUTH_INVALID_REFRESH", "invalid refresh token")
		return
	}

	access, err := h.tm.GenerateAccessToken(claims.UserID, claims.Username, claims.Timezone)
	if err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	newRefresh, newJTI, newExp, err := h.tm.GenerateRefreshToken(claims.UserID, claims.Username, claims.Timezone)
	if err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	if err := h.db.Transaction(func(tx *gorm.DB) error {
		now := time.Now().UTC()
		if err := tx.Model(&model.RefreshSession{}).Where("id = ?", session.ID).Updates(map[string]any{"revoked_at": &now, "replaced_by": newJTI}).Error; err != nil {
			return err
		}
		if err := tx.Create(&model.RefreshSession{UserID: claims.UserID, JTI: newJTI, ExpiresAt: newExp}).Error; err != nil {
			return err
		}
		return nil
	}); err != nil {
		bizError(c, "auth", "refresh", "REFRESH_ROTATE_FAILED", err, map[string]any{"uid": claims.UserID, "old_jti": claims.ID, "new_jti": newJTI})
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	secure := strings.EqualFold(strings.TrimSpace(c.GetHeader("X-Forwarded-Proto")), "https") || c.Request.TLS != nil
	c.SetSameSite(http.SameSiteLaxMode)
	c.SetCookie("refresh_token", newRefresh, h.tm.RefreshMaxAgeSeconds(), "/api/v1/auth/refresh", "", secure, true)

	bizInfo(c, "auth", "refresh", map[string]any{"uid": claims.UserID, "old_jti": claims.ID, "new_jti": newJTI})
	c.JSON(http.StatusOK, gin.H{
		"access_token": access,
		"token_type":   "Bearer",
	})
}

type createCategoryRequest struct {
	Name  string `json:"name" binding:"required"`
	Type  string `json:"type" binding:"required,oneof=real digital"`
	Color string `json:"color"`
}

func (h *Handler) CreateCategory(c *gin.Context) {
	userID := c.GetUint("user_id")
	var req createCategoryRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		bizError(c, "category", "create", "BAD_REQUEST", err, nil)
		JSONBadRequest(c, "BAD_REQUEST", "invalid request", err.Error())
		return
	}

	cat := model.Category{
		UserID: userID,
		Name:   strings.TrimSpace(req.Name),
		Type:   req.Type,
		Color:  strings.TrimSpace(req.Color),
	}
	if cat.Name == "" {
		bizError(c, "category", "create", "CATEGORY_NAME_REQUIRED", nil, nil)
		JSONBadRequest(c, "CATEGORY_NAME_REQUIRED", "name is required", nil)
		return
	}

	if err := h.db.Create(&cat).Error; err != nil {
		if strings.Contains(strings.ToLower(err.Error()), "unique") {
			bizError(c, "category", "create", "CATEGORY_DUPLICATE", err, map[string]any{"name": cat.Name})
			JSONError(c, http.StatusConflict, "CATEGORY_DUPLICATE", "category already exists", nil)
			return
		}
		bizError(c, "category", "create", "INTERNAL_ERROR", err, nil)
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	bizInfo(c, "category", "create", map[string]any{"category_id": cat.ID, "name": cat.Name})
	c.JSON(http.StatusCreated, gin.H{"data": cat})
}

func (h *Handler) ListCategories(c *gin.Context) {
	userID := c.GetUint("user_id")
	var categories []model.Category
	if err := h.db.Where("user_id = ?", userID).Order("id desc").Find(&categories).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	c.JSON(http.StatusOK, gin.H{"data": categories})
}

type createAssetRequest struct {
	Name       string  `json:"name" binding:"required"`
	CategoryID uint    `json:"category_id" binding:"required"`
	Quantity   float64 `json:"quantity" binding:"required"`
	UnitPrice  float64 `json:"unit_price" binding:"required"`
	Currency   string  `json:"currency" binding:"required"`
	ExpiryDate string  `json:"expiry_date"`
	Note       string  `json:"note"`
	Status     string  `json:"status"`
}

type updateAssetRequest struct {
	Name       *string  `json:"name"`
	CategoryID *uint    `json:"category_id"`
	Quantity   *float64 `json:"quantity"`
	UnitPrice  *float64 `json:"unit_price"`
	Currency   *string  `json:"currency"`
	ExpiryDate *string  `json:"expiry_date"`
	Note       *string  `json:"note"`
	Status     *string  `json:"status"`
}

func parseExpiryToUTC(raw string) (*time.Time, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return nil, nil
	}
	parsed, err := time.Parse(time.RFC3339, raw)
	if err != nil {
		return nil, err
	}
	u := parsed.UTC()
	return &u, nil
}

func (h *Handler) CreateAsset(c *gin.Context) {
	userID := c.GetUint("user_id")
	var req createAssetRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		bizError(c, "asset", "create", "BAD_REQUEST", err, nil)
		JSONBadRequest(c, "BAD_REQUEST", "invalid request", err.Error())
		return
	}

	if req.Quantity < 0 || req.UnitPrice < 0 {
		JSONBadRequest(c, "ASSET_NEGATIVE_VALUE", "quantity and unit_price must be >= 0", nil)
		return
	}

	currency := strings.ToUpper(strings.TrimSpace(req.Currency))
	if !currencyPattern.MatchString(currency) {
		JSONBadRequest(c, "ASSET_INVALID_CURRENCY", "currency must match [A-Z]{3,10}", nil)
		return
	}

	status := strings.TrimSpace(req.Status)
	if status == "" {
		status = "active"
	}
	if status != "active" && status != "inactive" {
		JSONBadRequest(c, "ASSET_INVALID_STATUS", "status must be active or inactive", nil)
		return
	}

	expiry, err := parseExpiryToUTC(req.ExpiryDate)
	if err != nil {
		JSONBadRequest(c, "ASSET_INVALID_EXPIRY", "expiry_date must be RFC3339", nil)
		return
	}

	var count int64
	if err := h.db.Model(&model.Category{}).Where("id = ? AND user_id = ?", req.CategoryID, userID).Count(&count).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	if count == 0 {
		JSONBadRequest(c, "CATEGORY_NOT_FOUND", "category not found", nil)
		return
	}

	asset := model.Asset{
		UserID:     userID,
		Name:       strings.TrimSpace(req.Name),
		CategoryID: req.CategoryID,
		Quantity:   req.Quantity,
		UnitPrice:  req.UnitPrice,
		TotalValue: req.Quantity * req.UnitPrice,
		Currency:   currency,
		ExpiryDate: expiry,
		Note:       strings.TrimSpace(req.Note),
		Status:     status,
	}
	if asset.Name == "" {
		JSONBadRequest(c, "CATEGORY_NAME_REQUIRED", "name is required", nil)
		return
	}

	if err := h.db.Create(&asset).Error; err != nil {
		bizError(c, "asset", "create", "INTERNAL_ERROR", err, nil)
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	h.ensureRemindersForAsset(asset)
	h.writeAudit(userID, "asset", asset.ID, "create", nil, asset)
	bizInfo(c, "asset", "create", map[string]any{"asset_id": asset.ID, "name": asset.Name})
	c.JSON(http.StatusCreated, gin.H{"data": formatAssetForTZ(asset, c.GetString("timezone"))})
}

func (h *Handler) UpdateAsset(c *gin.Context) {
	userID := c.GetUint("user_id")
	assetID := c.Param("id")

	var asset model.Asset
	if err := h.db.Where("id = ? AND user_id = ?", assetID, userID).First(&asset).Error; err != nil {
		bizError(c, "asset", "update", "ASSET_NOT_FOUND", err, map[string]any{"asset_id": assetID})
		JSONError(c, http.StatusNotFound, "ASSET_NOT_FOUND", "asset not found", nil)
		return
	}
	before := asset

	var req updateAssetRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		bizError(c, "asset", "update", "BAD_REQUEST", err, map[string]any{"asset_id": asset.ID})
		JSONBadRequest(c, "BAD_REQUEST", "invalid request", err.Error())
		return
	}

	if req.Name != nil {
		asset.Name = strings.TrimSpace(*req.Name)
		if asset.Name == "" {
			JSONBadRequest(c, "ASSET_NAME_EMPTY", "name cannot be empty", nil)
			return
		}
	}
	if req.CategoryID != nil {
		var count int64
		if err := h.db.Model(&model.Category{}).Where("id = ? AND user_id = ?", *req.CategoryID, userID).Count(&count).Error; err != nil {
			JSONInternal(c, "internal server error", err.Error())
			return
		}
		if count == 0 {
			JSONBadRequest(c, "CATEGORY_NOT_FOUND", "category not found", nil)
			return
		}
		asset.CategoryID = *req.CategoryID
	}
	if req.Quantity != nil {
		if *req.Quantity < 0 {
			JSONBadRequest(c, "ASSET_QUANTITY_NEGATIVE", "quantity must be >= 0", nil)
			return
		}
		asset.Quantity = *req.Quantity
	}
	if req.UnitPrice != nil {
		if *req.UnitPrice < 0 {
			JSONBadRequest(c, "ASSET_UNIT_PRICE_NEGATIVE", "unit_price must be >= 0", nil)
			return
		}
		asset.UnitPrice = *req.UnitPrice
	}
	if req.Currency != nil {
		cur := strings.ToUpper(strings.TrimSpace(*req.Currency))
		if !currencyPattern.MatchString(cur) {
			JSONBadRequest(c, "ASSET_INVALID_CURRENCY", "currency must match [A-Z]{3,10}", nil)
			return
		}
		asset.Currency = cur
	}
	if req.Status != nil {
		status := strings.TrimSpace(*req.Status)
		if status != "active" && status != "inactive" {
			JSONBadRequest(c, "ASSET_INVALID_STATUS", "status must be active or inactive", nil)
			return
		}
		asset.Status = status
	}
	if req.Note != nil {
		asset.Note = strings.TrimSpace(*req.Note)
	}
	if req.ExpiryDate != nil {
		expiry, err := parseExpiryToUTC(*req.ExpiryDate)
		if err != nil {
			JSONBadRequest(c, "ASSET_INVALID_EXPIRY", "expiry_date must be RFC3339", nil)
			return
		}
		asset.ExpiryDate = expiry
	}

	asset.TotalValue = asset.Quantity * asset.UnitPrice
	if err := h.db.Save(&asset).Error; err != nil {
		bizError(c, "asset", "update", "INTERNAL_ERROR", err, map[string]any{"asset_id": asset.ID})
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	h.ensureRemindersForAsset(asset)
	h.writeAudit(userID, "asset", asset.ID, "update", before, asset)
	bizInfo(c, "asset", "update", map[string]any{"asset_id": asset.ID, "status": asset.Status})
	c.JSON(http.StatusOK, gin.H{"data": formatAssetForTZ(asset, c.GetString("timezone"))})
}

func (h *Handler) DeleteAsset(c *gin.Context) {
	userID := c.GetUint("user_id")
	assetID := c.Param("id")

	var asset model.Asset
	if err := h.db.Where("id = ? AND user_id = ?", assetID, userID).First(&asset).Error; err != nil {
		bizError(c, "asset", "delete", "ASSET_NOT_FOUND", err, map[string]any{"asset_id": assetID})
		JSONError(c, http.StatusNotFound, "ASSET_NOT_FOUND", "asset not found", nil)
		return
	}

	if err := h.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("asset_id = ? AND user_id = ?", asset.ID, userID).Delete(&model.Reminder{}).Error; err != nil {
			return err
		}
		if err := tx.Delete(&asset).Error; err != nil {
			return err
		}
		log := model.AuditLog{
			UserID:     userID,
			EntityType: "asset",
			EntityID:   asset.ID,
			Action:     "delete",
			BeforeJSON: toJSON(asset),
			AfterJSON:  "null",
		}
		return tx.Create(&log).Error
	}); err != nil {
		bizError(c, "asset", "delete", "INTERNAL_ERROR", err, map[string]any{"asset_id": asset.ID})
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	bizInfo(c, "asset", "delete", map[string]any{"asset_id": asset.ID})
	c.JSON(http.StatusOK, gin.H{"message": "deleted", "request_id": requestID(c)})
}

func (h *Handler) ListAssets(c *gin.Context) {
	userID := c.GetUint("user_id")
	var assets []model.Asset
	query := h.db.Model(&model.Asset{}).Where("user_id = ?", userID).Order("id desc")

	categoryID := strings.TrimSpace(c.Query("category_id"))
	if categoryID != "" {
		query = query.Where("category_id = ?", categoryID)
	}

	status := strings.TrimSpace(c.Query("status"))
	if status != "" {
		if status != "active" && status != "inactive" {
			JSONBadRequest(c, "ASSET_INVALID_STATUS", "status must be active or inactive", nil)
			return
		}
		query = query.Where("status = ?", status)
	}

	page := 1
	pageSize := 20
	if p := strings.TrimSpace(c.Query("page")); p != "" {
		fmt.Sscanf(p, "%d", &page)
	}
	if ps := strings.TrimSpace(c.Query("page_size")); ps != "" {
		fmt.Sscanf(ps, "%d", &pageSize)
	}
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}
	offset := (page - 1) * pageSize

	var total int64
	if err := query.Count(&total).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}
	if err := query.Offset(offset).Limit(pageSize).Find(&assets).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	resp := make([]gin.H, 0, len(assets))
	for _, a := range assets {
		resp = append(resp, formatAssetForTZ(a, c.GetString("timezone")))
	}

	c.JSON(http.StatusOK, gin.H{"data": resp, "total": total, "page": page, "page_size": pageSize})
}

func (h *Handler) PublicRecords(c *gin.Context) {
	tz := strings.TrimSpace(c.Query("timezone"))
	if tz == "" {
		tz = "Asia/Shanghai"
	}

	var assets []model.Asset
	if err := h.db.Where("user_id = ?", 1).Order("updated_at desc").Limit(100).Find(&assets).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	var categories []model.Category
	_ = h.db.Where("user_id = ?", 1).Find(&categories).Error
	catName := map[uint]string{}
	for _, x := range categories {
		catName[x.ID] = x.Name
	}

	total := 0.0
	activeCount := 0
	byCat := map[string]float64{}
	resp := make([]gin.H, 0, len(assets))
	for _, a := range assets {
		if a.Status == "active" {
			total += a.TotalValue
			activeCount++
			byCat[catName[a.CategoryID]] += a.TotalValue
		}
		row := formatAssetForTZ(a, tz)
		row["category_name"] = catName[a.CategoryID]
		resp = append(resp, row)
	}

	c.JSON(http.StatusOK, gin.H{
		"summary": gin.H{
			"user_id":             1,
			"active_asset_count":  activeCount,
			"total_assets_value":  total,
			"by_category":         byCat,
		},
		"records": resp,
	})
}

func (h *Handler) ListReminders(c *gin.Context) {
	userID := c.GetUint("user_id")
	query := h.db.Model(&model.Reminder{}).Where("user_id = ?", userID).Order("status asc, remind_at asc, id desc")

	status := strings.TrimSpace(c.Query("status"))
	if status != "" {
		allowed := map[string]bool{"pending": true, "sending": true, "sent": true, "failed": true}
		if !allowed[status] {
			JSONBadRequest(c, "REMINDER_INVALID_STATUS", "invalid status", nil)
			return
		}
		query = query.Where("status = ?", status)
	}

	page := 1
	pageSize := 20
	if p := strings.TrimSpace(c.Query("page")); p != "" {
		fmt.Sscanf(p, "%d", &page)
	}
	if ps := strings.TrimSpace(c.Query("page_size")); ps != "" {
		fmt.Sscanf(ps, "%d", &pageSize)
	}
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}
	offset := (page - 1) * pageSize

	var total int64
	if err := query.Count(&total).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	var rows []model.Reminder
	if err := query.Offset(offset).Limit(pageSize).Find(&rows).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	assetIDs := make([]uint, 0, len(rows))
	for _, r := range rows {
		assetIDs = append(assetIDs, r.AssetID)
	}
	nameMap := map[uint]string{}
	if len(assetIDs) > 0 {
		var assets []model.Asset
		_ = h.db.Where("id IN ? AND user_id = ?", assetIDs, userID).Find(&assets).Error
		for _, a := range assets {
			nameMap[a.ID] = a.Name
		}
	}

	loc, err := time.LoadLocation(c.GetString("timezone"))
	if err != nil {
		loc = time.UTC
	}
	resp := make([]gin.H, 0, len(rows))
	for _, r := range rows {
		item := gin.H{
			"id":           r.ID,
			"asset_id":     r.AssetID,
			"asset_name":   nameMap[r.AssetID],
			"remind_at":    r.RemindAt.In(loc).Format(time.RFC3339),
			"channel":      r.Channel,
			"status":       r.Status,
			"retry_count":  r.RetryCount,
			"last_error":   r.LastError,
			"created_at":   r.CreatedAt.In(loc).Format(time.RFC3339),
			"updated_at":   r.UpdatedAt.In(loc).Format(time.RFC3339),
		}
		if r.SentAt != nil {
			item["sent_at"] = r.SentAt.In(loc).Format(time.RFC3339)
		}
		if r.NextRetryAt != nil {
			item["next_retry_at"] = r.NextRetryAt.In(loc).Format(time.RFC3339)
		}
		resp = append(resp, item)
	}

	c.JSON(http.StatusOK, gin.H{"data": resp, "total": total, "page": page, "page_size": pageSize})
}

func (h *Handler) DashboardSummary(c *gin.Context) {
	userID := c.GetUint("user_id")
	var assets []model.Asset
	if err := h.db.Where("user_id = ? AND status = ?", userID, "active").Find(&assets).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	total := 0.0
	for _, a := range assets {
		total += a.TotalValue
	}

	type categoryAgg struct {
		CategoryID   uint    `json:"category_id"`
		CategoryName string  `json:"category_name"`
		TotalValue   float64 `json:"total_value"`
		Ratio        float64 `json:"ratio"`
	}

	nameMap := map[uint]string{}
	var categories []model.Category
	_ = h.db.Where("user_id = ?", userID).Find(&categories).Error
	for _, cat := range categories {
		nameMap[cat.ID] = cat.Name
	}

	byCatMap := map[uint]float64{}
	for _, a := range assets {
		byCatMap[a.CategoryID] += a.TotalValue
	}

	byCategory := make([]categoryAgg, 0, len(byCatMap))
	for categoryID, v := range byCatMap {
		ratio := 0.0
		if total > 0 {
			ratio = v / total
		}
		byCategory = append(byCategory, categoryAgg{
			CategoryID:   categoryID,
			CategoryName: nameMap[categoryID],
			TotalValue:   v,
			Ratio:        ratio,
		})
	}

	sort.Slice(byCategory, func(i, j int) bool { return byCategory[i].TotalValue > byCategory[j].TotalValue })

	nowUTC := time.Now().UTC()
	endUTC := nowUTC.Add(30 * 24 * time.Hour)
	var expiring []model.Asset
	if err := h.db.Where("user_id = ? AND status = ? AND expiry_date IS NOT NULL AND expiry_date >= ? AND expiry_date <= ?", userID, "active", nowUTC, endUTC).Order("expiry_date asc").Find(&expiring).Error; err != nil {
		JSONInternal(c, "internal server error", err.Error())
		return
	}

	expiringResp := make([]gin.H, 0, len(expiring))
	for _, a := range expiring {
		expiringResp = append(expiringResp, formatAssetForTZ(a, c.GetString("timezone")))
	}

	c.JSON(http.StatusOK, gin.H{
		"total_assets_value":   total,
		"by_category":          byCategory,
		"expiring_in_30_days": expiringResp,
	})
}

func formatAssetForTZ(a model.Asset, tz string) gin.H {
	loc, err := time.LoadLocation(tz)
	if err != nil {
		loc = time.UTC
	}
	var expiry any
	if a.ExpiryDate != nil {
		expiry = a.ExpiryDate.In(loc).Format(time.RFC3339)
	}
	return gin.H{
		"id":          a.ID,
		"name":        a.Name,
		"category_id": a.CategoryID,
		"quantity":    a.Quantity,
		"unit_price":  a.UnitPrice,
		"total_value": a.TotalValue,
		"currency":    a.Currency,
		"expiry_date": expiry,
		"note":        a.Note,
		"status":      a.Status,
		"created_at":  a.CreatedAt.In(loc).Format(time.RFC3339),
		"updated_at":  a.UpdatedAt.In(loc).Format(time.RFC3339),
	}
}

func (h *Handler) ensureRemindersForAsset(asset model.Asset) {
	_ = h.db.Where("asset_id = ? AND user_id = ? AND status IN ?", asset.ID, asset.UserID, []string{"pending", "failed", "sending"}).Delete(&model.Reminder{}).Error
	if asset.ExpiryDate == nil || asset.Status != "active" {
		return
	}
	base := asset.ExpiryDate.UTC()
	days := []int{30, 7, 1}
	for _, d := range days {
		remindAt := base.Add(-time.Duration(d) * 24 * time.Hour)
		dedupe := fmt.Sprintf("asset:%d:at:%s:ch:in_app", asset.ID, remindAt.Format(time.RFC3339))
		r := model.Reminder{
			UserID:    asset.UserID,
			AssetID:   asset.ID,
			RemindAt:  remindAt,
			Channel:   "in_app",
			Status:    "pending",
			DedupeKey: dedupe,
		}
		_ = h.db.Clauses(clause.OnConflict{Columns: []clause.Column{{Name: "dedupe_key"}}, DoNothing: true}).Create(&r).Error
	}
}