golifx-import-products.go

package main

import (
	"bytes"
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"github.com/pdf/golifx/protocol/v2/device"
)

type vendorSorter []*device.Vendor

func (s vendorSorter) Len() int           { return len(s) }
func (s vendorSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s vendorSorter) Less(i, j int) bool { return s[i].ID < s[j].ID }

type productSorter []*device.Product

func (s productSorter) Len() int           { return len(s) }
func (s productSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s productSorter) Less(i, j int) bool { return s[i].ID < s[j].ID }

func usage() {
	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
	fmt.Fprintf(os.Stderr, "\t%s [flags] <path/to/products.json>\n", os.Args[0])
	fmt.Fprintf(os.Stderr, "Flags:\n")
	flag.PrintDefaults()
}

func main() {
	var (
		output = flag.String(`output`, ``, `Output path; must be set`)
		err    error
	)

	log.SetFlags(0)
	log.SetPrefix(`golifx-import-products: `)
	flag.Usage = usage
	flag.Parse()
	if len(flag.Args()) != 1 || len(*output) == 0 {
		flag.Usage()
		os.Exit(2)
	}

	in, err := ioutil.ReadFile(flag.Args()[0])
	if err != nil {
		log.Fatalln(err)
	}

	var vendors vendorSorter
	if err = json.Unmarshal(in, &vendors); err != nil {
		log.Fatalln(err)
	}
	sort.Sort(vendors)

	g := &Generator{}

	g.Printf("// Code generated by \"golifx-import-products %s\"; DO NOT EDIT\n\n", strings.Join(os.Args[1:], " "))
	g.Printf("package device\n\n")
	g.Printf("var (\n")
	g.Printf("\t// Vendors automatically generated from products.json\n")
	g.Printf("\tVendors = map[uint32]Vendor{\n")
	for _, vendor := range vendors {
		g.Printf("\t\t%d: Vendor{\n", vendor.ID)
		g.Printf("\t\t\tID: %d,\n", vendor.ID)
		g.Printf("\t\t\tName: `%s`,\n", vendor.Name)
		g.Printf("\t\t\tProducts: map[uint32]*Product{\n")
		products := make(productSorter, len(vendor.Products))
		i := 0
		for _, product := range vendor.Products {
			products[i] = product
			i++
		}
		sort.Sort(products)
		for _, product := range products {
			g.Printf("\t\t\t\t%d: &Product{ID: %d, VendorID: %d, Name: `%s`, Features: %d},\n", product.ID, product.ID, vendor.ID, product.Name, product.Features)
		}
		g.Printf("\t\t\t},\n")
		g.Printf("\t\t},\n")
	}
	g.Printf("\t}\n")
	g.Printf(")\n")

	g.Write(filepath.Join(*output, `vendors_import.go`))

}

// Generator provides the output buffer and helper functions
type Generator struct {
	buf bytes.Buffer
}

// Printf prints formatted strings to the buffer
func (g *Generator) Printf(format string, a ...interface{}) {
	if _, err := fmt.Fprintf(&g.buf, format, a...); err != nil {
		log.Fatalln(err)
	}
}

// Write outputs the buffer to the specified file path
func (g *Generator) Write(output string) {
	if err := ioutil.WriteFile(output, g.buf.Bytes(), 0644); err != nil {
		log.Fatalln(err)
	}
}