feat: add comprehensive inventory management system

.gitignore

@@ -29,4 +29,5 @@ core_api
 core_rpc
 
 # VsCode debug files
-__debug*
+__debug*api/logs/
+*.log

INVENTORY_TESTING_GUIDE.md

@@ -0,0 +1,386 @@
+# Inventory Management System - Testing & Troubleshooting Guide
+
+## 🚀 Quick Start
+
+### Prerequisites
+```bash
+# Ensure Go is installed
+go version
+
+# Install dependencies
+go mod tidy
+
+# Set up database (if using PostgreSQL/MySQL)
+# Update your database connection in config files
+```
+
+### Start the Application
+```bash
+# Start API server
+cd api
+go run .
+
+# Start RPC server (in another terminal)
+cd rpc
+go run .
+
+# Or use docker-compose if available
+docker-compose up -d
+```
+
+### Run Tests
+```bash
+# Make test script executable
+chmod +x test-inventory-system.sh
+
+# Run comprehensive tests
+./test-inventory-system.sh
+```
+
+---
+
+## 🧪 Manual Testing Guide
+
+### 1. Health Check
+```bash
+# Test API server
+curl http://localhost:9100/health
+
+# Expected response: {"status": "ok"}
+```
+
+### 2. Warehouse Operations
+
+#### Create Warehouse
+```bash
+curl -X POST http://localhost:9100/inventory/warehouse \
+  -H "Content-Type: application/json" \
+  -d '{
+    "name": "Main Warehouse",
+    "location": "123 Industrial St",
+    "capacity": 10000,
+    "description": "Primary storage facility"
+  }'
+```
+
+#### Get Warehouse
+```bash
+curl http://localhost:9100/inventory/warehouse/1
+```
+
+#### Update Warehouse
+```bash
+curl -X PUT http://localhost:9100/inventory/warehouse/1 \
+  -H "Content-Type: application/json" \
+  -d '{
+    "name": "Main Warehouse Updated",
+    "capacity": 15000
+  }'
+```
+
+#### List Warehouses
+```bash
+curl http://localhost:9100/inventory/warehouse
+```
+
+#### Delete Warehouse
+```bash
+curl -X DELETE http://localhost:9100/inventory/warehouse/1
+```
+
+### 3. Product Operations
+
+#### Create Product
+```bash
+curl -X POST http://localhost:9100/inventory/product \
+  -H "Content-Type: application/json" \
+  -d '{
+    "name": "Laptop Computer",
+    "sku": "LT-001",
+    "description": "High-performance laptop",
+    "price": 1299.99,
+    "category": "Electronics",
+    "brand": "TechCorp"
+  }'
+```
+
+#### Get Product
+```bash
+curl http://localhost:9100/inventory/product/1
+```
+
+#### List Products
+```bash
+curl http://localhost:9100/inventory/product
+```
+
+### 4. Inventory Operations
+
+#### Create Inventory Record
+```bash
+curl -X POST http://localhost:9100/inventory/stock \
+  -H "Content-Type: application/json" \
+  -d '{
+    "product_id": 1,
+    "warehouse_id": 1,
+    "quantity": 100,
+    "min_stock_level": 10,
+    "max_stock_level": 500
+  }'
+```
+
+#### Update Stock Quantity
+```bash
+curl -X PUT http://localhost:9100/inventory/stock/1 \
+  -H "Content-Type: application/json" \
+  -d '{
+    "quantity": 150
+  }'
+```
+
+### 5. Stock Movement Operations
+
+#### Record Stock Movement (IN)
+```bash
+curl -X POST http://localhost:9100/inventory/movement \
+  -H "Content-Type: application/json" \
+  -d '{
+    "product_id": 1,
+    "warehouse_id": 1,
+    "movement_type": "IN",
+    "quantity": 25,
+    "reference": "PO-2024-001",
+    "notes": "Received new stock"
+  }'
+```
+
+#### Record Stock Movement (OUT)
+```bash
+curl -X POST http://localhost:9100/inventory/movement \
+  -H "Content-Type: application/json" \
+  -d '{
+    "product_id": 1,
+    "warehouse_id": 1,
+    "movement_type": "OUT",
+    "quantity": 10,
+    "reference": "SO-2024-001",
+    "notes": "Sold to customer"
+  }'
+```
+
+---
+
+## 🔧 Troubleshooting Guide
+
+### Common Issues & Solutions
+
+#### 1. API Server Not Starting
+```bash
+# Check for compilation errors
+go build ./api/...
+
+# Check database connection
+# Verify your database credentials in config files
+
+# Check port availability
+lsof -i :9100
+```
+
+#### 2. Database Connection Issues
+```bash
+# Test database connection
+# For PostgreSQL:
+psql -h localhost -U your_user -d your_db
+
+# For MySQL:
+mysql -h localhost -u your_user -p your_db
+
+# Check Ent schema generation
+go generate ./rpc/ent
+```
+
+#### 3. gRPC Service Issues
+```bash
+# Test gRPC service connectivity
+grpcurl -plaintext localhost:9090 list
+
+# Check protobuf compilation
+protoc --go_out=. --go-grpc_out=. rpc/desc/*.proto
+```
+
+#### 4. Ent ORM Issues
+```bash
+# Regenerate Ent entities
+go generate ./rpc/ent
+
+# Check for schema conflicts
+go run rpc/ent/migrate/main.go
+```
+
+#### 5. Test Failures
+
+##### Warehouse Tests Failing
+```bash
+# Check warehouse table schema
+# Verify foreign key constraints
+# Check database permissions
+```
+
+##### Product Tests Failing
+```bash
+# Verify product table structure
+# Check unique constraints on SKU
+# Validate data types
+```
+
+##### Inventory Tests Failing
+```bash
+# Ensure warehouse and product exist before inventory creation
+# Check referential integrity constraints
+# Verify quantity validation logic
+```
+
+##### Stock Movement Tests Failing
+```bash
+# Ensure inventory record exists
+# Check movement type validation
+# Verify quantity doesn't go negative
+```
+
+#### 6. Performance Issues
+```bash
+# Add database indexes
+# Check query performance
+# Monitor memory usage
+```
+
+---
+
+## 🐛 Debugging Steps
+
+### 1. Enable Debug Logging
+```go
+// Add to your main.go or server files
+import "log"
+log.SetFlags(log.LstdFlags | log.Lshortfile)
+
+// Enable verbose logging
+os.Setenv("LOG_LEVEL", "debug")
+```
+
+### 2. Database Query Debugging
+```bash
+# Enable SQL query logging in Ent
+client := ent.Open("postgres", dsn,
+    ent.Log(func(a ...any) {
+        log.Println(a...)
+    }),
+)
+```
+
+### 3. API Request Debugging
+```bash
+# Use curl with verbose output
+curl -v http://localhost:9100/inventory/warehouse
+
+# Check request/response headers
+curl -I http://localhost:9100/inventory/warehouse
+```
+
+### 4. gRPC Debugging
+```bash
+# Install grpcurl
+go install github.com/fullstorydev/grpcurl/cmd/grpcurl@latest
+
+# List services
+grpcurl -plaintext localhost:9090 list
+
+# Call service methods
+grpcurl -plaintext -d '{"id": 1}' localhost:9090 core.WarehouseService/GetWarehouse
+```
+
+---
+
+## 📊 Test Coverage Checklist
+
+### Warehouse Management ✅
+- [x] Create warehouse
+- [x] Get warehouse by ID
+- [x] Update warehouse
+- [x] List warehouses
+- [x] Delete warehouse
+- [x] Validation (required fields, capacity limits)
+
+### Product Management ✅
+- [x] Create product
+- [x] Get product by ID
+- [x] Update product
+- [x] List products
+- [x] Delete product
+- [x] SKU uniqueness validation
+- [x] Price validation
+
+### Inventory Management ✅
+- [x] Create inventory record
+- [x] Update stock levels
+- [x] Get inventory by ID
+- [x] List inventory records
+- [x] Delete inventory
+- [x] Stock level alerts (min/max)
+- [x] Referential integrity
+
+### Stock Movement Tracking ✅
+- [x] Record stock movements (IN/OUT)
+- [x] Movement audit trail
+- [x] Reference tracking
+- [x] Quantity validation
+- [x] Movement history
+
+### Integration Tests ✅
+- [x] End-to-end workflows
+- [x] Cross-entity operations
+- [x] Error handling
+- [x] Data consistency
+
+---
+
+## 🚀 Production Deployment Checklist
+
+### Pre-Deployment
+- [ ] Database backup
+- [ ] Schema migrations tested
+- [ ] Performance benchmarks
+- [ ] Security audit
+- [ ] API documentation updated
+
+### Deployment
+- [ ] Zero-downtime deployment
+- [ ] Database connection pooling
+- [ ] Health checks configured
+- [ ] Monitoring setup
+- [ ] Rollback plan ready
+
+### Post-Deployment
+- [ ] Smoke tests passed
+- [ ] Performance monitoring
+- [ ] Error tracking
+- [ ] User acceptance testing
+
+---
+
+## 📞 Support
+
+If you encounter issues:
+
+1. **Check the troubleshooting section above**
+2. **Run the automated test script**: `./test-inventory-system.sh`
+3. **Review application logs**
+4. **Verify database connectivity**
+5. **Check network configurations**
+
+For additional help, please provide:
+- Error messages
+- Application logs
+- Database schema
+- Test output
+- System information