code and example

2 files changed, 280 insertions, 0 deletions

diff --git a/example.json b/example.json
new file mode 100644
index 0000000..164344a
--- /dev/null
+++ b/example.json
@@ -0,0 +1,127 @@
+{
+	"Kits": [
+		{"Name": "general", "Items": [
+			"phone",
+			"phone charger",
+			"keys",
+			"train ticket"
+		]}, 
+		{"Name": "clothing", "Items": [
+			"t-shirt",
+			"pullover",
+			"trousers"
+		]}, 
+		{"Name": "tent", "Items": [
+			"tent",
+		       	"sleeping bag",
+			"sleeping pad"
+		]}, 
+		{"Name": "first aid", "Items": [
+		       	"first aid set"
+		]},
+		{"Name": "stuff", "Items": [
+		       	"headlamp",
+		       	"multitool",
+		       	"knife",
+		       	"camera"
+		]}
+	],
+
+	"Items": [
+		{
+			"Name": "t-shirt",
+		       	"Scale": 2,
+		       	"Number": 1,
+		       	"Weight": 170,
+		       	"Limit": 3
+		}, 
+		{
+			"Name": "sleeping bag",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 620
+		}, 
+		{
+			"Name": "sleeping pad",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 680
+		}, 
+		{
+			"Name": "tent",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 1950
+		},
+		{
+			"Name": "camera",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 440,
+			"Note": "charge batteries"
+		},
+		{
+			"Name": "first aid set",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 660
+		},
+		{
+			"Name": "phone",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 72,
+			"Note": "charge batteries, check prepaid account"
+		},
+		{
+			"Name": "phone charger",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 45
+		},
+		{
+			"Name": "head lamp",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 90,
+			"Note": "pack additional batteries"
+		},
+		{
+			"Name": "multitool",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 330
+		},
+		{
+			"Name": "knife",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 250
+		},
+		{
+			"Name": "pullover",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 500,
+		},
+		{
+			"Name": "trousers",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 750,
+			"Spare": true
+		},
+		{
+			"Name": "keys",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 150
+		},
+		{
+			"Name": "train ticket",
+			"Scale": 0,
+			"Number": 1,
+			"Weight": 0
+		}
+	]
+}
diff --git a/packliste.go b/packliste.go
new file mode 100644
index 0000000..ed739f6
--- /dev/null
+++ b/packliste.go
@@ -0,0 +1,153 @@
+package main
+
+// TODO: Warn if undefined items are referenced
+// TODO: Compact items defined multiple times in a kit
+
+import (
+	"fmt"
+	"encoding/json"
+	"os"
+	"log"
+	"math"
+	"strconv"
+)
+
+type Item struct {
+	Name	string
+	Note	string
+	Weight	float64
+	Scale	int
+	Number	int
+	Spare	bool
+	Limit	int
+}
+
+type Kit struct {
+	Name	string
+	Items	[]string
+}
+
+type List struct {
+	Kits	[]Kit
+	Items	[]Item
+}
+
+var kits map[string]Kit
+var items map[string]Item
+var notes []string
+
+func main() {
+
+	if len(os.Args) < 4 {
+		fmt.Printf("Usage: %s filename days kit [kit] ...\n", os.Args[0])
+		os.Exit(1)
+	}
+	
+	// arguments
+	
+	filename := os.Args[1]
+	
+	days, err := strconv.Atoi(os.Args[2])
+	
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// open JSON data
+
+	file, err := os.Open(filename)
+
+	if err != nil {
+		log.Fatal(err)
+	}
+	
+	// parse data
+	
+	dec := json.NewDecoder(file)
+	
+	var l List
+	err = dec.Decode(&l)
+		
+	if err != nil {
+		log.Fatal(err)
+	}
+	
+	// make maps of kits and items
+	
+	kits = make(map[string]Kit, 16)
+	
+	for _, kit := range l.Kits {
+		kits[kit.Name] = kit
+	}
+	
+	items = make(map[string]Item, 64)
+	
+	for _, item := range l.Items {
+		items[item.Name] = item
+	}
+
+	// iterate over kit names provided on command line
+
+	var weight float64
+
+	for _, kitname := range os.Args[3:] {
+		weight += useKit(kitname, days)	
+	}
+	
+	fmt.Printf("\nTotal weight: %.3fkg\n", weight / 1000)
+	
+	fmt.Println("\n\nNotes: ")
+	
+	for _, note := range notes {
+		fmt.Printf("* %s\n", note)
+	}
+
+}
+
+func useKit(kitname string, days int) float64 {
+
+	var weight float64
+	var qty int
+	
+	fmt.Printf("=== %s ===\n", kitname)
+	
+	for _, itemname := range kits[kitname].Items {
+	
+		item, present := items[itemname]
+	
+		if !present {
+			continue
+		}
+
+		// Scale == 0 means there will be item.Number items,
+		// independent of the number of days
+		if item.Scale == 0 {
+			qty = item.Number
+		} else {
+			qty = int( math.Ceil(float64(item.Number) / float64(item.Scale) * float64(days)))
+		}
+		
+		// Spare == true means there will one spare set added
+		if item.Spare {
+			qty += item.Number
+		}
+		
+		// TODO: Should this be (item.Limit * item.Number), or is the
+		// current solution fine? Unsure. Need to use brain.
+		if item.Limit > 0 && qty > (item.Limit) {
+			qty = item.Limit
+		}
+
+		weight += float64(qty) * item.Weight
+		
+		if item.Note != "" {
+			notes = append(notes, item.Name + ": " + item.Note)
+		}
+		
+		fmt.Printf("%d x %s\n", qty, item.Name)
+	}
+
+	fmt.Printf("--- %.3fkg\n", weight/1000)
+	
+	return weight
+}