#!/usr/bin/env python3
import subprocess
import select
import time

import config
import logging.config
logging.config.dictConfig(config.logging)
log = logging.getLogger('progrunner')

from flask import Flask, request, session
from flask_restful import Api, Resource

app = Flask(__name__)
api = Api(app)
app.config.from_object(config)

class Authenticator(Resource):
    def post(self):
        log.info("received login request %s", request.json)
        if request.json and request.json.get("token", None) == config.token:
            session["authorized"] = True
            log.info("session: %s", session)
            return { "authorized": True }
        else:
            session["authorized"] = False
            log.info("session: %s", session)
            return { "authorized": False }

running = []

class Starter(Resource):
    def post(self):
        log.info("session: %s", session)
        if not session.get("authorized", False):
            return {}

        log.info("json: %s", request.json)
        args = [ request.json["program"] ]
        if "args" in request.json:
            args += request.json["args"]
        log.info("args: %s", args)
        proc = subprocess.Popen(
                            args,
                            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                            universal_newlines=True)
        procinfo = { "popen": proc, "pid": proc.pid, "started": time.time(), "stdout": [], "stderr": [] }
        running.append(procinfo)
        pid = proc.pid
        log.info("pid: %s", pid)
        timeout = request.json.get("timeout", 0.0)
        log.debug("timeout: %s", timeout)
        if timeout:
            get_output(procinfo, timeout)
        try:
            procinfo["status"] = proc.wait(0.1)
            for ln in proc.stdout:
                procinfo["stdout"].append(ln)
            for ln in proc.stderr:
                procinfo["stderr"].append(ln)
            procinfo["finished"] = time.time()
        except subprocess.TimeoutExpired:
            pass
        return { x: procinfo[x]
                    for x in ["pid", "started", "stdout", "stderr", "status", "finished"]
                        if x in procinfo }

class Status(Resource):
    def get(self, pid):
        for procinfo in running:
            if "finished" not in procinfo:
                get_output(procinfo, 1.0)
                try:
                    procinfo["status"] = procinfo["popen"].wait(0.1)
                    procinfo["finished"] = time.time()
                except subprocess.TimeoutExpired:
                    pass
        for procinfo in running:
            if procinfo["pid"] == pid:
                return { x: procinfo[x]
                            for x in ["pid", "started", "stdout", "stderr", "status", "finished"]
                                if x in procinfo }

def get_output(procinfo, timeout):
    proc = procinfo["popen"]
    p = select.poll()
    p.register(proc.stdout)
    p.register(proc.stderr)
    t0 = time.time()
    t1 = t0 + timeout
    eof = False
    while not eof:
        dt = t1 - time.time()
        if dt < 0:
            break
        ready = p.poll(dt * 1000)
        log.debug("ready: %s", ready)
        for fd in ready:

            if fd[0] == proc.stdout.fileno():
                ln = proc.stdout.readline()
                log.debug("ln: %s", ln)
                if ln == "":
                    eof = True
                    continue
                procinfo["stdout"].append(ln)
            if fd[0] == proc.stderr.fileno():
                ln = proc.stderr.readline()
                log.debug("ln: %s", ln)
                if ln == "":
                    eof = True
                    continue
                procinfo["stderr"].append(ln)



api.add_resource(
        Authenticator,
        "/login"
    )
api.add_resource(
        Starter,
        "/start"
    )
api.add_resource(
        Status,
        "/status/<int:pid>"
    )


if __name__ == '__main__':
    app.run()