#!/usr/bin/env python3

from http.server import BaseHTTPRequestHandler, HTTPServer
from http import HTTPStatus
import ssl
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, exc
from multiprocessing import Process, Queue
from enum import Enum, IntEnum
import os
import signal
import json
import sys
import logging
import logging.handlers
import argparse
import datetime
import subprocess
import paramiko
import hashlib
import shutil
from smtplib import SMTP
from email.mime.text import MIMEText

from lib import db

Session = sessionmaker()

allbuilders = {}
users = {}

def __sendEmail(to_addrs, subject, body):
    if to_addrs:
        with SMTP(args.smtpserver + "." + args.smtpdomain, port=25) as smtpClient:
            sender = args.smtpsender + "@" + args.smtpdomain
            msg = MIMEText(body)
            msg['Subject'] = "INAU. " + subject
            msg['From'] = sender
            msg['To'] = ', '.join(to_addrs)
            d = smtpClient.sendmail(from_addr=sender, to_addrs=list(to_addrs), msg=msg.as_string())
            print("Email sent to ", list(to_addrs), d)

def sendEmail(recipients, subject, body):
    notifiable = set()
    for user in users:
        if (user.notify==True):
            notifiable.add(user.name + "@" + args.smtpdomain)
    to_addrs = set(recipients).intersection(notifiable)
    __sendEmail(to_addrs, subject, body)

def sendEmailAdmins(subject, body):
    to_addrs = set()
    for user in users:
        if (user.admin==True):
            to_addrs.add(user.name + "@" + args.smtpdomain)
    __sendEmail(to_addrs, subject, body)

class Die:
    pass

class Update:
    def __init__(self, repository_name, repository_url, build_tag, default_branch):
        self.repository_name = repository_name
        self.repository_url = repository_url
        self.build_tag = build_tag
        self.default_branch = default_branch

class Build(Update):
    def __init__(self, repository_name, repository_url, build_tag, default_branch):
        Update.__init__(self, repository_name, repository_url, build_tag, default_branch)
        self.status = ''
        self.output = ''

class Store(Build):
    def __init__(self, repository_name, repository_url, build_tag, repository_id, repository_type, emails, default_branch):
        Build.__init__(self, repository_name, repository_url, build_tag, default_branch)
        self.repository_id = repository_id
        self.repository_type = repository_type
        self.emails = emails

class Builder:
    def __init__(self, name, platform_id, environment):
        self.name = name
        self.platform_id = platform_id
        self.platdir = args.repo + '/' + str(platform_id)
        if environment is None:
            self.environment = ""
        else:
            self.environment = "source " + environment + "; "
        self.queue = Queue()
        self.process = Process(target=self.handler)
        self.process.start()

    def update(self, job):
        logger.info("[" + self.name + "] Checkouting " + job.build_tag + " from " + job.repository_url + "...")
        builddir = self.platdir + "/" + job.repository_name
        buildcmd = ""
        if not os.path.isdir(self.platdir):
            os.mkdir(self.platdir)

        if not os.path.isdir(self.platdir + "/cs/ds/makefiles"):
            buildcmd += "git clone --recurse-submodule https://gitlab.elettra.eu/cs/ds/makefiles.git " + self.platdir + "/cs/ds/makefiles"
        else:
            buildcmd += "git -C " + self.platdir + "/cs/ds/makefiles remote update"
            buildcmd += " && git -C " + self.platdir + "/cs/ds/makefiles reset --hard origin/master"

        if not os.path.isdir(builddir):
            buildcmd += " && git clone --recurse-submodule " + job.repository_url + " " + builddir
        buildcmd += " && git -C " + builddir + " remote update"
        buildcmd += " && git -C " + builddir + " pull --tags"
        buildcmd += " && git -C " + builddir + " branch --no-color --contains " + job.build_tag + " | grep '\<" + job.default_branch + "\>'"
        buildcmd += " && git -C " + builddir + " reset --hard " + job.build_tag + " --"
        buildcmd += " && git -C " + builddir + " submodule update --init --force --recursive"
        subprocess.run(buildcmd, shell=True, check=True)

    def build(self, job):
        logging.info("[" + self.name + "] Building " + job.build_tag + " from " + job.repository_url + "...")
        builddir = self.platdir + "/" + job.repository_name
        with paramiko.SSHClient() as sshClient:
            sshClient.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            sshClient.connect(hostname=self.name, port=22, username="inau",
                    key_filename="/home/inau/.ssh/id_rsa.pub")
            if job.repository_type != db.RepositoryType.library:
                _, raw, _ = sshClient.exec_command("(" + self.environment + "source /etc/profile; cd " + builddir
                        + "; make -j`getconf _NPROCESSORS_ONLN`) 2>&1")
            else:
                _, raw, _ = sshClient.exec_command("(" + self.environment + "source /etc/profile; cd " + builddir
                        + "; make -j`getconf _NPROCESSORS_ONLN` && rm -fr .install && PREFIX=.install make install)  2>&1")
            job.status = raw.channel.recv_exit_status()
            job.output = raw.read().decode('latin-1') # FIXME utf-8 is rejected by Mysql despite it is properly configured

    def store(self, job):
        logging.info("[" + self.name + "] Storing " + job.build_tag + " from " + job.repository_url + "...")
            
        build = db.Builds(repository_id=job.repository_id, platform_id=self.platform_id, tag=os.path.basename(job.build_tag), 
                status=job.status, output=job.output)
        self.session.add(build)
        self.session.commit()

        builddir = self.platdir + "/" + job.repository_name
        outcome = job.repository_name + " " + os.path.basename(job.build_tag) 
        if job.status != 0:
            outcome += ": built failed on " + self.name
        else:
            outcome += ": built successfully on " + self.name
            if job.repository_type == db.RepositoryType.cplusplus or job.repository_type == db.RepositoryType.python \
                    or job.repository_type == db.RepositoryType.shellscript:
                basedir = builddir + "/bin/"
            elif job.repository_type == db.RepositoryType.configuration:
                basedir = builddir + "/etc/"
            elif job.repository_type == db.RepositoryType.library:
                basedir = builddir + "/.install/"
            else:
                raiseException('Invalid type')

            artifacts = []
            for rdir_abs, _, fnames in os.walk(basedir):
                for fname in fnames:
                    fname_abs = os.path.join(rdir_abs, fname)
                    rdir_rel = os.path.relpath(rdir_abs, basedir)
                    fname_rel = os.path.join(rdir_rel, fname)
                    if not os.path.islink(fname_abs):
                        with open(fname_abs,"rb") as fd:
                                bytes = fd.read()
                                hashFile = hashlib.sha256(bytes).hexdigest()
                                hashDir = hashFile[0:2] + "/" + hashFile[2:4]
                                if not os.path.isdir(args.store + hashDir):
                                    os.makedirs(args.store + hashDir, exist_ok=True)
                                if not os.path.isfile(args.store + hashFile):
                                    shutil.copyfile(fname_abs, args.store + hashDir + "/" + hashFile, follow_symlinks=False)
                                artifacts.append(db.Artifacts(build_id=build.id, hash=hashFile, filename=fname_rel))
                    else:
                        artifacts.append(db.Artifacts(build_id=build.id, filename=fname_rel,
                            symlink_target=os.path.join(rdir_rel, os.readlink(fname_abs))))
            self.session.add_all(artifacts)
            self.session.commit()
        sendEmail(job.emails, outcome, job.output)

    def handler(self):
        logger.info("[" + self.name + "] Starting process for builder " +  self.name + "...")
            
        engine.dispose()
        self.session = Session()
        while True:
            try:
                job = self.queue.get()
                if isinstance(job, Die):
                    logger.info("[" + self.name + "] Stopping process for builder " + self.name + "...")
                    break

                if isinstance(job, Update):
                    self.update(job)

                if isinstance(job, Build):
                    self.build(job)

                if isinstance(job, Store):
                    self.store(job)

            except subprocess.CalledProcessError as c:
                sendEmailAdmins("Subprocess failed", str(c))
                logger.error("Subprocess failed: ", str(c))
                self.session.rollback()
            except Exception as e:
                sendEmailAdmins("Generic error", str(e))
                logger.error("Generic error: ", str(e))
                self.session.rollback()
            except KeyboardInterrupt as k:
                self.session.rollback()
                break
            finally:
                self.session.close()

def signalHandler(signalNumber, frame):
    reconcile()

def reconcile():
    logger.info('Reconciling...')

    session = Session()
    try:
        global allbuilders
        global users

        users = session.query(db.Users).all()

        newbuilders = {}
        oldbuilders = allbuilders
        for b in session.query(db.Builders).all():
            try:
                newbuilders[b.platform_id].append(Builder(b.name, b.platform_id, b.environment))
            except KeyError:
                newbuilders[b.platform_id] = [Builder(b.name, b.platform_id, b.environment)]
        allbuilders = newbuilders

        for oldbuilder in oldbuilders.values():
            for b in oldbuilder:
                b.queue.put(Die())
                b.process.join()
    except Exception as e:
        sendEmailAdmins("Reconcilation failed", str(e))
        logger.error("Reconciliation failed: ", str(e))
        session.rollback()
    finally:
        session.close()

class Server(BaseHTTPRequestHandler):
    def do_POST(self):
        engine.dispose()
        session = Session()
        try:
            content_length = int(self.headers['Content-Length']) 
            post_data = self.rfile.read(content_length)

            if self.headers['Content-Type'] != 'application/json':
                self.send_response(HTTPStatus.UNSUPPORTED_MEDIA_TYPE.value)
                self.end_headers()
                return

            post_json = json.loads(post_data.decode('utf-8'))
            logger.debug(post_json)
            print(post_json)

            # Tag deletion
            if post_json['after'] == '0000000000000000000000000000000000000000':
                self.send_response(HTTPStatus.OK.value)
                self.end_headers()
                return

            # Check if the tag is lightweight
            if post_json['after'] == post_json['commits'][0]['id']:
                self.send_response(HTTPStatus.OK.value)
                self.end_headers()
                return

            for r in session.query(db.Repositories).filter(db.Repositories.name==post_json['project']['path_with_namespace']).all():
                if self.headers['X-Gitlab-Event'] == 'Tag Push Hook' and post_json['event_name'] == 'tag_push' and r.enabled:
                    job = Store(repository_name = r.name, repository_url = post_json['project']['ssh_url'], build_tag=post_json['ref'],
                            repository_id = r.id, repository_type = r.type, emails=[post_json['commits'][0]['author']['email'], 
                                post_json['user_username'] + '@elettra.eu', post_json['user_email']],
                            default_branch=post_json['project']['default_branch'])
                else:
                    continue

                # Assign the job to the builder with shortest queue length
                idx = allbuilders[r.platform_id].index(min(allbuilders[r.platform_id], 
                    key=lambda x:x.queue.qsize()))
                logger.info("Assign building of " + r.name + " to " + allbuilders[r.platform_id][idx].name)
                allbuilders[r.platform_id][idx].queue.put(job)

            self.send_response(HTTPStatus.OK.value)
            self.end_headers()

        except Exception as e:
            sendEmailAdmins("Receive new tag failed", str(e))
            logger.error("Receive new tag failed: ", str(e))
            session.rollback()
            self.send_response(HTTPStatus.INTERNAL_SERVER_ERROR.value)
            self.end_headers()
        finally:
            session.close()

def run(address, port, server_class=HTTPServer, handler_class=Server):
    logger.info('Starting...')
    server_address = (address, port)
    httpd = server_class(server_address, handler_class)
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        pass
    httpd.server_close()
    logger.info('Stopping...')

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument("--db", type=str, help='Database URI to connect to', required=True)
    parser.add_argument('--bind', type=str, default='localhost', help='IP Address or hostname to bind to')
    parser.add_argument('--port', type=int, default=443, help='Port to listen to')
    parser.add_argument("--store", type=str, default='/scratch/build/files-store/', help='Directory where store produced binaries')
    parser.add_argument("--repo", type=str, default='/scratch/build/repositories/', help='Directory where checkout git repositories')
    parser.add_argument("--smtpserver", type=str, default="smtp", help='Hostname of the SMTP server')
    parser.add_argument("--smtpsender", type=str, default="noreply", help='Email sender')
    parser.add_argument("--smtpdomain", type=str, default="elettra.eu", help='Email domain')
    args = parser.parse_args()

    print("Start inau-dispatcher using", args.db, "on interface", args.bind, "and port", 
            args.port, "file store directory", args.store, "repositories clone directory", args.repo, 
            "SMTP server", args.smtpserver, "SMTP sender", args.smtpsender, "SMTP domain", args.smtpdomain)

    if os.getpgrp() == os.tcgetpgrp(sys.stdout.fileno()):
        # Executed in foreground so redirect log to terminal and enable SQL echoing (Development)
        logging.basicConfig(level=logging.INFO)
        engine = create_engine(args.db, pool_pre_ping=True, echo=True)
    else:
        # Executed in background so redirect log to syslog and disable SQL echoing (Production)
        syslog_handler = logging.handlers.SysLogHandler(address='/dev/log')
        logging.basicConfig(level=logging.INFO, handlers=[syslog_handler])
        engine = create_engine(args.db, pool_pre_ping=True, echo=False)
    logger = logging.getLogger('inau-dispatcher')

    Session.configure(bind=engine)

    reconcile()
    signal.signal(signal.SIGHUP, signalHandler)

    if args.bind:
            run(args.bind,args.port)