import {Inject, Singleton} from "../di"
import {HTTPStatus, withTimeout} from "../util"
import {Unit} from "../lifecycle/Unit";
import {createServer, IncomingMessage, Server, ServerResponse} from "http";
import {Logging} from "./Logging";
import {Request} from "../http/lifecycle/Request";
import {HTTPKernel} from "../http/kernel/HTTPKernel";
import {PoweredByHeaderInjectionHTTPModule} from "../http/kernel/module/PoweredByHeaderInjectionHTTPModule";
import {SetSessionCookieHTTPModule} from "../http/kernel/module/SetSessionCookieHTTPModule";
import {InjectSessionHTTPModule} from "../http/kernel/module/InjectSessionHTTPModule";
import {PersistSessionHTTPModule} from "../http/kernel/module/PersistSessionHTTPModule";
import {MountActivatedRouteHTTPModule} from "../http/kernel/module/MountActivatedRouteHTTPModule";
import {ExecuteResolvedRouteHandlerHTTPModule} from "../http/kernel/module/ExecuteResolvedRouteHandlerHTTPModule";
import {error} from "../http/response/ErrorResponseFactory";
import {ExecuteResolvedRoutePreflightHTTPModule} from "../http/kernel/module/ExecuteResolvedRoutePreflightHTTPModule";
import {ExecuteResolvedRoutePostflightHTTPModule} from "../http/kernel/module/ExecuteResolvedRoutePostflightHTTPModule";
import {ParseIncomingBodyHTTPModule} from "../http/kernel/module/ParseIncomingBodyHTTPModule";
import {Config} from "./Config";

/**
 * Application unit that starts the HTTP/S server, creates Request and Response objects
 * for it, and handles those requests using the HTTPKernel.
 */
@Singleton()
export class HTTPServer extends Unit {
    @Inject()
    protected readonly logging!: Logging

    @Inject()
    protected readonly config!: Config

    @Inject()
    protected readonly kernel!: HTTPKernel

    /** The underlying native Node.js server. */
    protected server?: Server

    public async up() {
        const port = this.config.get('server.port', 8000)

        // TODO register these by config
        PoweredByHeaderInjectionHTTPModule.register(this.kernel)
        SetSessionCookieHTTPModule.register(this.kernel)
        InjectSessionHTTPModule.register(this.kernel)
        PersistSessionHTTPModule.register(this.kernel)
        MountActivatedRouteHTTPModule.register(this.kernel)
        ExecuteResolvedRouteHandlerHTTPModule.register(this.kernel)
        ExecuteResolvedRoutePreflightHTTPModule.register(this.kernel)
        ExecuteResolvedRoutePostflightHTTPModule.register(this.kernel)
        ParseIncomingBodyHTTPModule.register(this.kernel)

        await new Promise<void>((res, rej) => {
            this.server = createServer(this.handler)

            this.server.listen(port, () => {
                this.logging.success(`Server listening on port ${port}. Press ^C to stop.`)
            })

            process.on('SIGINT', res)
        })
    }

    public async down() {
        if ( this.server ) {
            this.server.close(err => {
                if ( err ) {
                    this.logging.error(`Error encountered while closing HTTP server: ${err.message}`)
                    this.logging.debug(err)
                }
            })
        }
    }

    public get handler() {
        const timeout = this.config.get('server.timeout', 10000)

        return async (request: IncomingMessage, response: ServerResponse) => {
            const extolloReq = new Request(request, response)

            withTimeout(timeout, extolloReq.response.sent$.toPromise())
                .onTime(req => {
                    this.logging.verbose(`Request lifecycle finished on time. (Path: ${extolloReq.path})`)
                })
                .late(req => {
                    if ( !extolloReq.bypassTimeout ) {
                        this.logging.warn(`Request lifecycle finished late, so an error response was returned! (Path: ${extolloReq.path})`)
                    }
                })
                .timeout(() => {
                    if ( extolloReq.bypassTimeout ) {
                        this.logging.info(`Request lifecycle has timed out, but bypassRequest was set. (Path: ${extolloReq.path})`)
                        return
                    }

                    this.logging.error(`Request lifecycle has timed out. Will send error response instead. (Path: ${extolloReq.path})`)
                    extolloReq.response.setStatus(HTTPStatus.REQUEST_TIMEOUT)
                    extolloReq.response.body = 'Sorry, your request timed out.'
                    extolloReq.response.send()
                })
                .run()
                .catch(e => this.logging.error(e))

            try {
                await this.kernel.handle(extolloReq)
            } catch (e) {
                await error(e).write(extolloReq)
            }

            await extolloReq.response.send()
        }
    }
}