package main

import (
	"log"
	"net/http"
	"os"
	"os/exec"

	"gopkg.in/go-playground/webhooks.v5/github"
)

const path = "/"

func onPush(w http.ResponseWriter, payload github.PushPayload) {
	if (payload.Ref != "refs/heads/master") {
		log.Printf("No-op: ref '%s' isn't of interest", payload.Ref)
		return
	}
	cmd := exec.Command("/bin/bash", "on-push.sh")
	cmd.Stdout = w
	cmd.Stderr = w
	err := cmd.Run()
	if err != nil {
		log.Println("Bash exec error: %s", err.Error())
		return
	}
	log.Println("Bash exec successful")
}

func main() {
	secret := os.Getenv("GITHUB_WEBHOOK_SECRET")
	if secret == "" {
		log.Println("Please provide a webhook secret with the GITHUB_WEBHOOK_SECRET environment variable.")
		return
	}
	hook, _ := github.New(github.Options.Secret(secret))

	http.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
		log.Println("New payload")
		payload, err := hook.Parse(r, github.PushEvent)
		if err != nil {
			if err != github.ErrEventNotFound {
				log.Println("Error: %#v\n", err)
			}
			return
		}
		switch typedPayload := payload.(type) {
		case github.PushPayload:
			onPush(w, typedPayload)
		default:
			log.Printf("Unknown payload type.\n%#v\n", typedPayload)
		}
	})
	log.Println("Listening")
	http.ListenAndServe(":4000", nil)
}