package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"time"
)

type input struct {
	Source json.RawMessage `json:"source"`
	Update bool            `json:"update"`
	Ticks  string          `json:"ticks"`
}

type sample struct {
	Elapsed  int64  `json:"elapsed_ns"`
	Checksum int    `json:"checksum"`
	Output   string `json:"output"`
}

func transform(source []byte, update bool) []byte {
	decoder := json.NewDecoder(bytes.NewReader(source))
	decoder.UseNumber()
	var object map[string]any
	if err := decoder.Decode(&object); err != nil {
		panic(err)
	}
	var selected any = object["data"]
	if update {
		object["active"] = true
		selected = object
	}
	output, err := json.Marshal(selected)
	if err != nil {
		panic(err)
	}
	return output
}

func main() {
	var arguments input
	if len(os.Args) != 2 {
		panic("expected one JSON input")
	}
	if err := json.Unmarshal([]byte(os.Args[1]), &arguments); err != nil {
		panic(err)
	}
	if !json.Valid(arguments.Source) {
		panic("invalid source")
	}
	output := transform(arguments.Source, arguments.Update)
	checksum := 0
	begin := time.Now()
	for range []byte(arguments.Ticks) {
		checksum += len(transform(arguments.Source, arguments.Update))
	}
	result := sample{time.Since(begin).Nanoseconds(), checksum, string(output)}
	encoded, err := json.Marshal(result)
	if err != nil {
		panic(err)
	}
	fmt.Println(string(encoded))
}