// Copyright 2016 <chaishushan{AT}gmail.com>. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build ignore

// Command makestatic reads a set of files and writes a Go source file to "static.go"
// that declares a map of string constants containing contents of the input files.
// It is intended to be invoked via "go generate" (directive in "gen.go").
package main

import (
	"bytes"
	"fmt"
	"go/format"
	"io/ioutil"
	"os"
	"unicode/utf8"
)

var files = []string{
	"hospital_list.20160508.json",
	"hospital_list.20160519.json",
	"pinyin1234.txt",
}

func main() {
	if err := makestatic(); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

func makestatic() error {
	w := new(bytes.Buffer)

	fmt.Fprintf(w, `
// Copyright 2016 <chaishushan{AT}gmail.com>. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Code generated by go generate; DO NOT EDIT!!!

package static

`[1:])

	fmt.Fprintf(w, "var Files = map[string]string{\n")
	for _, fn := range files {
		b, err := ioutil.ReadFile(fn)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "\t%q: ", fn)
		if utf8.Valid(b) {
			fmt.Fprintf(w, "`%s`", sanitize(b))
		} else {
			fmt.Fprintf(w, "%q", b)
		}
		fmt.Fprintln(w, ",\n")
	}
	fmt.Fprintln(w, "}")

	data, err := format.Source(w.Bytes())
	if err != nil {
		return err
	}
	err = ioutil.WriteFile("static.go", data, 0644)
	if err != nil {
		return err
	}
	return nil
}

// sanitize prepares a valid UTF-8 string as a raw string constant.
func sanitize(b []byte) []byte {
	// Replace ` with `+"`"+`
	b = bytes.Replace(b, []byte("`"), []byte("`+\"`\"+`"), -1)

	// Replace BOM with `+"\xEF\xBB\xBF"+`
	// (A BOM is valid UTF-8 but not permitted in Go source files.
	// I wouldn't bother handling this, but for some insane reason
	// jquery.js has a BOM somewhere in the middle.)
	return bytes.Replace(b, []byte("\xEF\xBB\xBF"), []byte("`+\"\\xEF\\xBB\\xBF\"+`"), -1)
}
