package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"

	"github.com/DheerendraRathor/GoTracer/models"
	"github.com/DheerendraRathor/GoTracer/tracer"
)

func main() {

	file, e := ioutil.ReadFile("mySpecFile.json")
	if e != nil {
		panic(fmt.Sprintf("File error: %v\n", e))
	}

	var env models.World
	json.Unmarshal(file, &env)

	/*
		This channel is used to track progress of ray tracing. If env.Settings.ShowProgress is set to true.
		On each pixel traced a `false` value is pushed to progress channel. And once all pixel are processed a `true` value is pushed into channel.

		It is responsibility of caller to create sufficiently large buffered channel and read it responsibly if env.Settings.ShowProgress is true.
		Otherwise program might hang.
	*/
	progress := make(chan *models.Pixel, 100)
	closeChan := make(chan bool)
	defer close(progress)

	go goTracer.GoTrace(&env, progress, closeChan)

	go func() {
		for pixel := range progress {
			if pixel == nil {
				// Rendering complete
				return
			}
			// Do processing with pixel here.
			// Want to generate JPEG? GIF? Real time rendering on UI? Show weird looking progress bar? Your call. You've the pixels now
		}
	}()

	// To stop rendering in middle, just pass a value to closeChan.
	// GoTracer does a non-blocking check on closeChan before rendering a pixel. If channel has a value, it will stop rendering and send nil to
	// progress channel.
	// Caveat: Existing goroutines for other pixel will continue to run.

}