feat(cli): add inventory tracking (add/list) with persistent json storage

src/pantry/core/inventory.go

@@ -0,0 +1,44 @@
+package core
+
+import (
+	"fmt"
+	"time"
+
+	"pantry/util"
+)
+
+type InventoryItem struct {
+	Name     string
+	Quantity float64
+	Unit     string
+	Expiry   *time.Time
+	AddedAt  time.Time
+}
+
+type Inventory struct {
+	Items []InventoryItem
+}
+
+func (p *Inventory) AddItem(item InventoryItem) {
+	for i, existing := range p.Items {
+		if existing.Name == item.Name {
+			p.Items[i].Quantity += item.Quantity
+			fmt.Printf("Updated %s, new quantity: %.2f %s\n", item.Name, p.Items[i].Quantity, item.Unit)
+			return
+		}
+	}
+	p.Items = append(p.Items, item)
+	fmt.Printf("Added %s, quantity: %.2f %s\n", item.Name, item.Quantity, item.Unit)
+}
+
+func (p *Inventory) ListItems() {
+	if len(p.Items) == 0 {
+		fmt.Printf("Pantry is empty\n")
+		return
+	}
+
+	fmt.Printf("Your pantry:\n")
+	for _, item := range p.Items {
+		fmt.Printf("- %s: %.2f %s, (%s)\n", item.Name, item.Quantity, item.Unit, util.DaysUntilExpiry(item.Expiry))
+	}
+}

src/pantry/core/storage.go

@@ -0,0 +1,39 @@
+package core
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+func SaveInventory(filename string, inventory *Inventory) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return fmt.Errorf("failed to create file: %s", err)
+	}
+	defer file.Close()
+
+	encoder := json.NewEncoder(file)
+	encoder.SetIndent("", "  ")
+	return encoder.Encode(inventory.Items)
+}
+
+func LoadInventory(filename string) (*Inventory, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return &Inventory{}, nil
+		}
+		return nil, fmt.Errorf("failed to open file: %s", err)
+	}
+	defer file.Close()
+
+	var items []InventoryItem
+	decoder := json.NewDecoder(file)
+	err = decoder.Decode(&items)
+	if err != nil {
+		return nil, fmt.Errorf("failed to decode inventory data: %w", err)
+	}
+
+	return &Inventory{Items: items}, nil
+}

src/pantry/main.go

@@ -1 +1,82 @@
-package pantry
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"time"
+
+	"pantry/core"
+	"pantry/util"
+)
+
+func main() {
+	dataFile := util.GetDefaultPath()
+	err := os.MkdirAll(filepath.Dir(dataFile), 0755)
+	if err != nil {
+		fmt.Println("Failed to create data directory:", err)
+		return
+	}
+
+	inventory, err := core.LoadInventory(dataFile)
+	if err != nil {
+		fmt.Println("Failed to load inventory:", err)
+		return
+	}
+
+	if len(os.Args) < 2 {
+		fmt.Println("Usage: inventory [add|list]")
+		return
+	}
+
+	command := os.Args[1]
+
+	switch command {
+	case "add":
+		if len(os.Args) < 5 {
+			fmt.Println("Usage: inventory add [name] [quantity] [unit] [expiry:YYYY-MM-DD]")
+			return
+		}
+
+		name := os.Args[2]
+
+		quantity, err := strconv.ParseFloat(os.Args[3], 64)
+		if err != nil {
+			fmt.Println("Invalid quantity")
+			return
+		}
+		unit := os.Args[4]
+
+		var expiry *time.Time
+		if len(os.Args) >= 6 {
+			parsed, err := time.Parse("2006-01-02", os.Args[5])
+			if err != nil {
+				fmt.Println("Invalid expiry date format. Expected YYYY-MM-DD")
+				return
+			}
+			expiry = &parsed
+		}
+
+		item := core.InventoryItem{
+			Name:     name,
+			Quantity: quantity,
+			Unit:     unit,
+			Expiry:   expiry,
+			AddedAt:  time.Now(),
+		}
+
+		inventory.AddItem(item)
+		err = core.SaveInventory(dataFile, inventory)
+		if err != nil {
+			fmt.Println("Failed to save inventory:", err)
+			return
+		}
+
+	case "list":
+		inventory.ListItems()
+
+	default:
+		fmt.Println("Unknown command:", command)
+	}
+}

src/pantry/util/dates.go

@@ -0,0 +1,23 @@
+package util
+
+import (
+	"fmt"
+	"time"
+)
+
+// DaysUntilExpiry - takes expiry time and returns as a string.
+func DaysUntilExpiry(expiry *time.Time) string {
+	if expiry == nil {
+		return "no expiry date"
+	}
+	days := int(expiry.Sub(time.Now()).Hours() / 24)
+	if days < 0 {
+		return "expired"
+	} else if days == 0 {
+		return "expires today"
+	} else if days == 1 {
+		return "in 1 day"
+	} else {
+		return fmt.Sprintf("in %d days", days)
+	}
+}

src/pantry/util/paths.go

@@ -0,0 +1,22 @@
+package util
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+func GetDefaultPath() string {
+	var base string
+
+	if runtime.GOOS == "windows" {
+		base = os.Getenv("APPDATA")
+	} else {
+		base = os.Getenv("XDG_CONFIG_HOME")
+		if base == "" {
+			base = filepath.Join(os.Getenv("HOME"), ".config")
+		}
+	}
+
+	return filepath.Join(base, "pantry", "inventory.json")
+}