feat: implement user data CSV export with dynamic metadata columns

backend/internal/handler/user_handler.go

@@ -6,6 +6,7 @@ import (
 	"baron-sso-backend/internal/service"
 	"baron-sso-backend/internal/utils"
 	"context"
+	"encoding/csv"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -541,6 +542,103 @@ func (h *UserHandler) BulkCreateUsers(c *fiber.Ctx) error {
 	})
 }
 
+func (h *UserHandler) ExportUsersCSV(c *fiber.Ctx) error {
+	search := strings.TrimSpace(c.Query("search"))
+	companyCode := strings.TrimSpace(c.Query("companyCode"))
+
+	var requesterRole string
+	var manageableSlugs []string
+	if profile, ok := c.Locals("user_profile").(*domain.UserProfileResponse); ok {
+		requesterRole = profile.Role
+		if requesterRole == domain.RoleTenantAdmin {
+			for _, t := range profile.ManageableTenants {
+				manageableSlugs = append(manageableSlugs, strings.ToLower(t.Slug))
+			}
+			if profile.CompanyCode != "" {
+				manageableSlugs = append(manageableSlugs, strings.ToLower(profile.CompanyCode))
+			}
+		}
+	}
+
+	// 1. Fetch Users using Repo for efficiency
+	users, _, err := h.UserRepo.List(c.Context(), 10000, 0, search, companyCode)
+	if err != nil {
+		return errorJSON(c, fiber.StatusInternalServerError, "failed to fetch users for export")
+	}
+
+	// 2. Filter by manageable tenants if tenant_admin
+	var filtered []domain.User
+	if requesterRole == domain.RoleTenantAdmin {
+		slugMap := make(map[string]bool)
+		for _, s := range manageableSlugs {
+			slugMap[s] = true
+		}
+		for _, u := range users {
+			if slugMap[strings.ToLower(u.CompanyCode)] {
+				filtered = append(filtered, u)
+			}
+		}
+	} else {
+		filtered = users
+	}
+
+	// 3. Set CSV Headers
+	c.Set("Content-Type", "text/csv")
+	c.Set("Content-Disposition", "attachment; filename=users_export_"+time.Now().Format("20060102")+".csv")
+
+	writer := csv.NewWriter(c)
+	defer writer.Flush()
+
+	// Header row
+	header := []string{"ID", "Email", "Name", "Role", "Status", "Tenant", "Department", "Position", "JobTitle", "CreatedAt"}
+
+	// Collect all possible metadata keys for dynamic columns
+	metaKeysMap := make(map[string]bool)
+	for _, u := range filtered {
+		for k := range u.Metadata {
+			metaKeysMap[k] = true
+		}
+	}
+	var metaKeys []string
+	for k := range metaKeysMap {
+		metaKeys = append(metaKeys, k)
+		header = append(header, "Meta:"+k)
+	}
+
+	if err := writer.Write(header); err != nil {
+		return err
+	}
+
+	// Data rows
+	for _, u := range filtered {
+		row := []string{
+			u.ID,
+			u.Email,
+			u.Name,
+			u.Role,
+			u.Status,
+			u.CompanyCode,
+			u.Department,
+			u.Position,
+			u.JobTitle,
+			u.CreatedAt.Format(time.RFC3339),
+		}
+		// Append metadata values in order
+		for _, k := range metaKeys {
+			val := ""
+			if v, ok := u.Metadata[k]; ok {
+				val = fmt.Sprintf("%v", v)
+			}
+			row = append(row, val)
+		}
+		if err := writer.Write(row); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func (h *UserHandler) BulkUpdateUsers(c *fiber.Ctx) error {
 	var req struct {
 		UserIDs []string `json:"userIds"`