#!/usr/bin/env python3

import getpass
import json
import os
import queue
import re
import subprocess
import sys
import tempfile
import threading
import time
import urllib.request
from datetime import datetime

DEBUG = False

LOCATION = 'europe-west1-d'

IMAGE_CREATION_VMS = {
    # Find the newest FreeBSD 11 image via:
    # gcloud compute images list --project freebsd-org-cloud-dev \
    #     --no-standard-images
    'buildkite-freebsd11': {
        'source_image': 'https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-1-stable-amd64-2017-12-28',
        'target_image_family': 'bazel-freebsd11',
        'scripts': [
            'setup-freebsd.sh',
            'install-buildkite-agent.sh'
        ]
    },
    'buildkite-ubuntu1404': {
        'source_image_project': 'ubuntu-os-cloud',
        'source_image_family': 'ubuntu-1404-lts',
        'target_image_family': 'buildkite-ubuntu1404',
        'scripts': [
            'shell-utils.sh',
            'setup-ubuntu.sh',
            'install-azul-zulu.sh',
            'install-bazel.sh',
            'install-buildkite-agent.sh',
            'install-docker.sh',
            'install-nodejs.sh',
            'install-python36.sh',
            'install-android-sdk.sh',
            'shutdown.sh'
        ]
    },
    'buildkite-ubuntu1604': {
        'source_image_project': 'ubuntu-os-cloud',
        'source_image_family': 'ubuntu-1604-lts',
        'target_image_family': 'buildkite-ubuntu1604',
        'scripts': [
            'shell-utils.sh',
            'setup-ubuntu.sh',
            'install-azul-zulu.sh',
            'install-bazel.sh',
            'install-buildkite-agent.sh',
            'install-docker.sh',
            'install-nodejs.sh',
            'install-python36.sh',
            'install-android-sdk.sh',
            'shutdown.sh'
        ]
    },
    # 'buildkite-windows2016': {
    #     'source_image_project': 'windows-cloud',
    #     'source_image_family': 'windows-2016',
    #     'target_image_family': 'buildkite-windows2016',
    #     'scripts': [
    #         'setup-windows2016.ps1'
    #     ]
    # }
    'buildkite-windows': {
        'source_image_project': 'windows-cloud',
        'source_image_family': 'windows-1709-core',
        'target_image_family': 'buildkite-windows',
        'scripts': [
            'setup-windows-manual.ps1'
        ]
    }
}

MY_IPV4 = urllib.request.urlopen('https://v4.ifconfig.co/ip').read().decode('us-ascii').strip()
# MY_IPV4 = urllib.request.urlopen('https://v4.ident.me').read().decode('us-ascii').strip()

PRINT_LOCK = threading.Lock()
WORK_QUEUE = queue.Queue()


def debug(*args, **kwargs):
    if DEBUG:
        with PRINT_LOCK:
            print(*args, **kwargs)


def run(args, **kwargs):
    debug('Running: %s' % ' '.join(args))
    return subprocess.run(args, **kwargs)


def wait_for_vm(vm, status):
    while True:
        result = run(['gcloud', 'compute', 'instances', 'describe', '--zone', LOCATION,
                      '--format', 'json', vm], check=True, stdout=subprocess.PIPE)
        current_status = json.loads(result.stdout)['status']
        if current_status == status:
            debug("wait_for_vm: VM %s reached status %s" % (vm, status))
            break
        else:
            debug("wait_for_vm: Waiting for VM %s to transition from status %s -> %s" %
                  (vm, current_status, status))
        time.sleep(1)


def print_pretty_logs(vm, log):
    with PRINT_LOCK:
        for line in log.splitlines():
            # Skip empty lines.
            if not line:
                continue
            if 'ubuntu' in vm:
                match = re.match(r'.*INFO startup-script: (.*)', line)
                if match:
                    print("%s: %s" % (vm, match.group(1)))
            # elif 'windows' in vm:
            #     match = re.match(r'.*windows-startup-script-ps1: (.*)', line)
            #     if match:
            #         print(match.group(1))
            else:
                print("%s: %s" % (vm, line))


def tail_serial_console(vm, until=None):
    next_start = '0'
    while True:
        result = run(['gcloud', 'compute', 'instances', 'get-serial-port-output', '--zone', LOCATION, '--start',
                      next_start, vm], stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
        if result.returncode != 0:
            break
        print_pretty_logs(vm, result.stdout)
        if until and until in result.stdout:
            break
        next_start = re.search(r'--start=(\d*)', result.stderr).group(1)


def merge_setup_scripts(scripts):
    # Merge all setup scripts into one.
    merged_script_path = tempfile.mkstemp()[1]
    with open(merged_script_path, 'w') as merged_script_file:
        for script in scripts:
            with open(script, 'r') as script_file:
                merged_script_file.write(script_file.read() + '\n')
    return merged_script_path


def create_vm(vm, params):
    merged_script_path = merge_setup_scripts(params['scripts'])
    try:
        cmd = ['gcloud', 'compute', 'instances', 'create', vm]
        cmd.extend(['--zone', LOCATION])
        cmd.extend(['--machine-type', 'n1-standard-8'])
        cmd.extend(['--network', 'buildkite'])
        if 'windows' in vm:
            cmd.extend(['--metadata-from-file', 'windows-startup-script-ps1=' + merged_script_path])
        else:
            cmd.extend(['--metadata-from-file', 'startup-script=' + merged_script_path])
        cmd.extend(['--min-cpu-platform', 'Intel Skylake'])
        cmd.extend(['--boot-disk-type', 'pd-ssd'])
        cmd.extend(['--boot-disk-size', '50GB'])
        if 'source_image' in params:
            cmd.extend(['--image', params['source_image']])
        else:
            cmd.extend(['--image-project', params['source_image_project']])
            cmd.extend(['--image-family', params['source_image_family']])
        run(cmd)
    finally:
        os.remove(merged_script_path)


def delete_vm(vm):
    run(['gcloud', 'compute', 'instances', 'delete', '--quiet', vm])


def create_image(vm, target_image_family):
    run(['gcloud', 'compute', 'images', 'create', vm, '--family',
         target_image_family, '--source-disk', vm, '--source-disk-zone', LOCATION])


# https://stackoverflow.com/a/25802742
def write_to_clipboard(output):
    process = subprocess.Popen(
        'pbcopy', env={'LANG': 'en_US.UTF-8'}, stdin=subprocess.PIPE)
    process.communicate(output.encode('utf-8'))


def print_windows_instructions(vm):
    run(['gcloud', 'compute', 'firewall-rules', 'create', getpass.getuser() + '-rdp',
         '--allow', 'tcp:3389,udp:3389', '--network', 'buildkite', '--source-ranges', MY_IPV4 + '/32'])
    pw = json.loads(run(['gcloud', 'compute', 'reset-windows-password', '--format', 'json', '--quiet',
                         vm], check=True, stdout=subprocess.PIPE).stdout)
    rdp_file = tempfile.mkstemp(suffix='.rdp')[1]
    with open(rdp_file, 'w') as f:
        f.write('full address:s:' + pw['ip_address'] + '\n')
        f.write('username:s:' + pw['username'] + '\n')
    run(['open', rdp_file])
    write_to_clipboard(pw['password'])
    with PRINT_LOCK:
        print('Use this password to connect to the Windows VM: ' + pw['password'])
        print('Please run the setup script C:\\setup.ps1 once you\'re logged in.')


def workflow(name, params):
    vm = "%s-image-%s" % (name, int(datetime.now().timestamp()))
    try:
        # Create the VM.
        create_vm(vm, params)

        # Wait for the VM to become ready.
        wait_for_vm(vm, 'RUNNING')

        if 'windows' in vm:
            # Wait for VM to be ready, then print setup instructions.
            tail_serial_console(vm, until='Instance setup finished.')
            print_windows_instructions(vm)

        # Continuously print the serial console.
        tail_serial_console(vm)

        # Wait for the VM to shutdown.
        wait_for_vm(vm, 'TERMINATED')

        # Create a new image from our VM.
        create_image(vm, params['target_image_family'])
    finally:
        delete_vm(vm)


def worker():
    while True:
        item = WORK_QUEUE.get()
        if not item:
            break
        try:
            workflow(**item)
        finally:
            WORK_QUEUE.task_done()


def main(argv=None):
    if argv is None:
        argv = sys.argv[1:]

    # Put VM creation instructions into the work queue.
    for name, params in IMAGE_CREATION_VMS.items():
        if argv and name not in argv:
            continue
        WORK_QUEUE.put({
            'name': name,
            'params': params
        })

    # Spawn worker threads that will create the VMs.
    threads = []
    for _ in range(WORK_QUEUE.qsize()):
        t = threading.Thread(target=worker)
        t.start()
        threads.append(t)

    # Wait for all VMs to be created.
    WORK_QUEUE.join()

    # Signal worker threads to exit.
    for _ in range(len(threads)):
        WORK_QUEUE.put(None)

    # Wait for worker threads to exit.
    for t in threads:
        t.join()

    return 0


if __name__ == '__main__':
    sys.exit(main())