# A nitcorn listener for Github hooks.
abstract class HookListener

	# Api client used to perform Github API requests.
	var api: GithubAPI

	# Host to listen.
	var host: String

	# Port to listen.
	var port: Int

	# VirtualHost listened
	private var vh: VirtualHost is noinit

	init do
		vh = new VirtualHost("{host}:{port}")
		vh.routes.add new Route("/", new HookAction(self))
	end

	# Verbosity level (0: quiet, 1: debug).
	# Default: 0
	var verbosity = 0

	# Print `message` if `lvl` <= `verbosity`
	fun message(lvl: Int, message: String) do
		if lvl <= verbosity then print message
	end

	# Start listening and responding to event.
	fun listen do
		message(1, "Hook listening on {host}:{port}")
		var factory = new HttpFactory.and_libevent
		factory.config.virtual_hosts.add vh
		factory.run
	end

	# How to build events from received json objects.
	fun event_factory(kind: String, json: String): nullable GithubEvent do
		if kind == "commit_comment" then
			return api.deserialize(json).as(CommitCommentEvent)
		else if kind == "create" then
			return api.deserialize(json).as(CreateEvent)
		else if kind == "delete" then
			return api.deserialize(json).as(DeleteEvent)
		else if kind == "deployment" then
			return api.deserialize(json).as(DeploymentEvent)
		else if kind == "deployment_status" then
			return api.deserialize(json).as(DeploymentStatusEvent)
		else if kind == "fork" then
			return api.deserialize(json).as(ForkEvent)
		else if kind == "issues" then
			return api.deserialize(json).as(IssuesEvent)
		else if kind == "issue_comment" then
			return api.deserialize(json).as(IssueCommentEvent)
		else if kind == "member" then
			return api.deserialize(json).as(MemberEvent)
		else if kind == "pull_request" then
			return api.deserialize(json).as(PullRequestEvent)
		else if kind == "pull_request_review_comment" then
			return api.deserialize(json).as(PullRequestPullCommentEvent)
		else if kind == "push" then
			return api.deserialize(json).as(PushEvent)
		else if kind == "status" then
			return api.deserialize(json).as(StatusEvent)
		end
		return null
	end

	# What to do when we receive an event from a hook?
	fun apply_event(event: GithubEvent) is abstract
end