#!/usr/bin/python3
"""install.py

- copy files from to_system into system directories
- set host name / network settings from boxtools/cfg file
"""

if bytes == str:
    raise NotImplementedError('python2 not supported')

import sys
import os
import filecmp
import shutil
import serial
import types
import socket
from subprocess import Popen, PIPE
from glob import glob
from ipaddress import IPv4Interface
from configparser import ConfigParser
from os.path import join, getmtime, exists, basename
from utils import get_config, ifname_mapping

if os.geteuid() != 0:
    exit("You need to have root privileges to run this script.\nPlease try again, this time using 'sudo'. Exiting.")

TOOLS = '/home/l_samenv/boxtools'

BOX_TYPES = {
   '00:0d:b9': 'apu',  # bare apu or control box
   'b8:27:eb': 'cm3',  # iono pi
   'd8:3a:dd': 'cm4',  # dual-eth-rpi
}

more_info = False

DEL = '__to_delete__'
CFGPATH = f'{TOOLS}/cfg/%s_%6.6x.cfg'
STARTUP_TEXT = f'{TOOLS}/startup_display.txt'

COMMENT = "; please refer to README.md for help"

CONFIG_TEMPLATE = f"""[NETWORK]
{COMMENT}
enp1s0=192.168.127.254
enp2s0=192.168.2.2
enp3s0=192.168.3.3
enp4s0=dhcp

[ROUTER]
{COMMENT}
3001=192.168.127.254:3001
"""

CONTROLBOX_TEMPLATE = f"""[NETWORK]
{COMMENT}
enp1s0=dhcp
enp2s0=192.168.1.1
enp3s0=192.168.2.2
enp4s0=192.168.3.3

[DISPLAY]
{COMMENT}
line0=startup...
line1=HOST
line2=ADDR
"""

DHCP_HEADER = """
default-lease-time 600;
max-lease-time 7200;
authoritative;
"""

ROUTER_TEMPLATE = f"""[Unit]
Description = Routing to locally connected hardware
After = network.target

[Service]
ExecStart = /usr/bin/python3 {TOOLS}/router.py

[Install]
WantedBy = multi-user.target
"""

FRAPPY_TEMPLATE = """[Unit]
Description = Running frappy server
After = network.target

[Service]
User = l_samenv
ExecStart = /usr/bin/python3 /home/l_samenv/frappy/bin/frappy-server %s

[Install]
WantedBy = multi-user.target
"""

DISPLAY_TEMPLATE = f"""[Unit]
Description = status display
After = network.target

[Service]
User = root
ExecStart = /usr/bin/python3 {TOOLS}/display.py -d

[Install]
WantedBy = multi-user.target
"""


pip_requirements = {
    'root': {},
    'l_samenv': {},
}


net_addr = {}  # dict <if name> of <ethernet address>
dhcp_server_cfg = []  # configuration for dhcp
main_info = {  # info to be determined depending on cfg
    'ifname': '',  # name of interface of wan (dhcp) port
    'addr': '',  # addr of wan port
    'hostname': socket.gethostname()  # effective or given host name
}

for netif in os.scandir('/sys/class/net'):
    if netif.name != 'lo':  # do not consider loopback interface
        with open(os.path.join(netif.path, 'address')) as f:
            addr = f.read().strip().lower()
        net_addr[netif.name] = addr

sorted_if = sorted(net_addr)
boxaddr = net_addr[sorted_if[0]]
boxid = int(''.join(boxaddr.split(':')[-3:]), 16) & 0xffffff
boxtype = BOX_TYPES.get(boxaddr[:8])
if boxtype != 'apu':
    ifname_mapping.clear()
TO_SYSTEM = f'{TOOLS}/to_{boxtype}'
if not exists(TO_SYSTEM):
    TO_SYSTEM = f'{TOOLS}/to_system'
os.chdir(TO_SYSTEM)


def frappy(cfg=None, port=None, requirements='', **kwds):
    if not cfg:
        return None
    req = pip_requirements['l_samenv']
    req[cfg] = '\n'.join(requirements.split(','))
    if port:
        cfg = '-p %s %s' % (port, cfg)
    with open('/home/l_samenv/frappy/requirements.txt') as f:
        req['frappy main'] = f.read()
    return FRAPPY_TEMPLATE % cfg


def router(**opts):
    if not opts:
        return None
    try:
        os.remove(join(TO_SYSTEM, 'etc/nftables.conf'))
        with open(f'{TOOLS}/requirements.txt') as f:
            pip_requirements['root']['tools'] = f.read()
    except FileNotFoundError:
        pass
    return ROUTER_TEMPLATE


def display_update(cfg):
    text = '\n'.join(cfg.get('startup_text', '').split('|')[:3])
    text = text.replace('HOST', main_info['hostname']) \
               .replace('ADDR', main_info['addr']) + '\n'
    if write_when_new(STARTUP_TEXT, text):
        print('change startup text')
        if doit:
            os.rename(STARTUP_TEXT, STARTUP_TEXT + '.todo')
        return True
    return False


def display(**opts):
    if not opts:
        return None
    return DISPLAY_TEMPLATE


def pip():
    for user, requirements in pip_requirements.items():
        if user == 'root':
            tmpname = join('/root', 'pip_requirements.tmp')
            pipcmd = 'pip3 install -r %s' % tmpname
        else:
            tmpname = join('/home', user, 'pip_requirements.tmp')
            pipcmd = 'sudo --user %s pip3 install --user -r %s' % (user, tmpname)
        filename = tmpname.replace('.tmp', '.txt')
        content = ''.join('# --- for %s ---\n%s\n' % kv for kv in requirements.items())
        if write_when_new(filename, content, True):
            if doit:
                os.rename(filename, tmpname)
                if os.system(pipcmd) == 0:
                    os.rename(tmpname, filename)
                else:
                    os.remove(tmpname)
            else:
                print(pipcmd)
            unix_cmd(pipcmd, stdout=None)
            show.dirty = True


SERVICES = dict(router=router, frappy=frappy, display=display)


def unix_cmd(command, always=False, stdout=PIPE):
    if doit or always:
        if not always:
            print('$ %s' % command)
        result = Popen(command.split(), stdout=stdout).communicate()[0]
        return (result or b'').decode()
    else:
        print('> %s' % command)


def write_when_new(filename, content, ignore_reduction=False):
    if content is None:
        lines = []
    else:
        if not content.endswith('\n'):
            content += '\n'
        lines = content.split('\n')
    try:
        with open(filename) as fil:
            old = fil.read()
    except FileNotFoundError:
        old = None
    if old == content:
        return False
    if ignore_reduction:
        content_set = set(v for v in lines if not v.startswith('#'))
        old_set = set(v for v in (old or '').split('\n') if not v.startswith('#'))
        content_set -= old_set
        if content_set:
            print(f"missing in {filename}: {(', '.join(content_set - old_set))}")
        else:
            return False
    if doit:
        if lines:
            with open(filename, 'w') as fil:
                fil.write(content)
        else:
            os.remove(filename)
    elif more_info:
        print('.' * 80)
        print('changes in', filename)
        old = [] if old is None else old.split('\n')
        top_lines = 0  # in case of empty loop
        for top_lines, (ol, ll) in enumerate(zip(old, lines)):
            if ol != ll:
                break
        bottom_lines = 0
        for bottom_lines, (ol, ll) in enumerate(zip(reversed(old[top_lines:]), reversed(lines[top_lines:]))):
            if ol != ll:
                break
        if bottom_lines == 0:
            old.append('')
            lines.append('')
            bottom_lines += 1
        print("===")
        print('\n'.join(old[:top_lines]))
        print('<<<')
        print('\n'.join(old[top_lines:-bottom_lines]))
        print('---')
        print('\n'.join(lines[top_lines:-bottom_lines]))
        print('>>>')
        print('\n'.join(old[-bottom_lines:-1]))
        print("===")
        print('.' * 80)
    return content


def create_if(name, cfg):
    if cfg == 'off':
        result = None
    elif cfg.startswith('wan') or cfg == 'dhcp':
        if main_info.get('mainif', name) != name:
            raise ValueError('can not have more than one WAN/DHCP port')
        main_info['mainif'] = name
        main_info['addr'] = net_addr[name]
        # default: all <= 192.0.0.0
        # others have to be added explicitly
        dhcp_server_cfg.append(('0.0.0.0/128.0.0.0', []))
        dhcp_server_cfg.append(('128.0.0.0/192.0.0.0', []))
        for nw in cfg.split(',')[1:]:
            nw = IPv4Interface(nw).network
            dhcp_server_cfg.append((nw.with_netmask, []))
        result = f"allow-hotplug {name}\niface {name} inet dhcp"
    else:
        cfgip = IPv4Interface(cfg)
        network = cfgip.network
        print('N', network, network.prefixlen)
        if network.prefixlen == 32:  # or no prefix specified
            otherip = IPv4Interface('%s/24' % cfgip.ip)
            network = otherip.network
            if str(cfgip.ip).endswith('.1'):
                cfgip = network.network_address + 2
            else:
                cfgip = network.network_address + 1
            dhcp_server_cfg.append((network.with_netmask, [(str(otherip.ip), str(otherip.ip))]))
            addr = str(cfgip)
        else:  # subnet with multiple adresses -> static adresses only. dhcp range not yet implemented
            addr = str(cfgip.ip)
        # result['NETMASK'] = network.netmask
        result = f"allow-hotplug {name}\niface {name} inet static\n    address {addr}/{network.prefixlen}"
    if result:
        return result + '\n'


def walk(action):
    for dirpath, _, files in os.walk('.'):
        syspath = dirpath[1:]  # remove leading '.'
        action.dirpath = dirpath
        action.syspath = syspath
        if files:
            match, mismatch, missing = filecmp.cmpfiles(dirpath, syspath, files)
            if mismatch:
                newer = [f for f in mismatch if getmtime(join(syspath, f)) > getmtime(join(dirpath, f))]
                if newer:
                    action.newer(newer)
                if len(newer) < len(mismatch):
                    newer = set(newer)
                    action.older([f for f in mismatch if f not in newer])
            if missing:
                if DEL in missing:
                    missing.remove(DEL)
                    with open(join(dirpath, DEL)) as fil:
                        to_delete = []
                        for fname in fil:
                            fname = fname.strip()
                            if fname and exists(join(syspath, fname)):
                                if exists(join(dirpath, fname)):
                                    print('ERROR: %s in %s, but also in repo -> ignored' % (fname, DEL))
                                else:
                                    to_delete.append(fname)
                        action.delete(to_delete)
                if missing:
                    action.missing(missing)


class Walker:
    def __init__(self):
        self.dirpath = None
        self.syspath = None


class Show(Walker):
    dirty = False

    def diff(self, title, files):
        self.dirty = True
        if more_info:
            for f in files:
                if f.endswith(more_info):
                    print('diff %s %s' % (join(self.dirpath, f), join(self.syspath, f)))
                    print('.' * 80)
        else:
            print('%s %s:\n  %s' % (title, self.syspath, ' '.join(files)))

    def show(self, title, dirpath, files):
        self.dirty = True
        if more_info:
            for f in files:
                print('cat %s' % join(dirpath, f))
                print('.' * 80)
        else:
            print('%s %s:\n  %s' % (title, self.syspath, ' '.join(files)))

    def newer(self, files):
        self.show('get from', self.dirpath, files)

    def older(self, files):
        self.show('replace in', self.dirpath, files)

    def missing(self, files):
        self.show('install in', self.dirpath, files)

    def delete(self, files):
        self.show('remove from', self.syspath, files)


class Do(Walker):
    def newer(self, files):
        for file in files:
            shutil.copy(join(self.syspath, file), join(self.dirpath, file))

    def older(self, files):
        for file in files:
            shutil.copy(join(self.dirpath, file), join(self.syspath, file))

    def missing(self, files):
        self.older(files)

    def delete(self, files):
        for file in files:
            os.remove(join(self.syspath, file))


def handle_config():
    cfgfile = None
    cfgfiles = []
    dhcp_server_cfg.clear()
    for file in glob(CFGPATH % ('*', boxid)):
         cfgfiles.append(file)
    if boxtype == 'apu':
        for i in [1, 2, 3]:
            bad = glob(CFGPATH % ('*', apuid+i))
            if bad:
                print('cfg files found with bad apu id (use net addr of leftmost plug)')
                print(bad)
                return False
    newhostname = main_info['hostname']
    if not cfgfiles:
        # determine if display is present
        disp = serial.Serial('/dev/ttyS1', baudrate=115200, timeout=1)
        disp.write(b'\x1b\x1b\x01\xf3')
        display_available = disp.read(8)[0:4] == b'\x1b\x1b\x05\xf3'
        if display_available:
            # leftmost interface labelled 'eth0'
            # main_info['mainif'] = sorted_if[0]
            typ = 'controlbox'
            template = CONTROLBOX_TEMPLATE
        else:
            # rightmost interface
            # main_info['mainif'] = sorted_if[-1]
            typ = 'bare apu'
            template = CONFIG_TEMPLATE
        print('no cfg file found for this', typ, f'with id {boxid:%6.6x} (hostname={hostname})')
        newhostname = input('enter host name: ')
        if not newhostname:
            print('no hostname given')
            return False
        cfgfile = CFGPATH % (newhostname, boxid)
        with open(cfgfile, 'w') as f:
            f.write(template)
    elif len(cfgfiles) > 1:
        print('ERROR: ambiguous cfg files: %s' % ', '.join(cfgfiles))
    else:
        cfgfile = cfgfiles[0]
    if cfgfile != CFGPATH % (newhostname, boxid):
        if cfgfile:
            newhostname = basename(cfgfile).rpartition('_')[0]
        if doit:
            os.system('sh sethostname.sh')
        else:
            if cfgfile:
                print('replace host name %r by %r' % (main_info['hostname'], newhostname))
                show.dirty = True
    main_info['hostname'] = newhostname
    if cfgfile is None:
        return False
    to_start = {}
    ifname = ''
    config = get_config()
    try:
        netcfg = config['NETWORK']
        for ifname in net_addr:
            content = create_if(ifname, netcfg.get(ifname, 'off'))
            # content = '\n'.join('%s=%s' % kv for kv in content.items())
            todo = write_when_new(f'/etc/network/interfaces.d/{ifname}', content)
            if todo and not more_info:
                print('change', ifname)
                show.dirty = True
                to_start[ifname] = 'if_restart'
        if dhcp_server_cfg:
            print(dhcp_server_cfg)
            content = [DHCP_HEADER]
            for subnet, rangelist in dhcp_server_cfg:
                try:
                    adr, mask = subnet.split('/')
                except Exception as e:
                    print(subnet, repr(e))
                    continue
                content.append('subnet %s netmask %s {\n' % (adr, mask))
                #content.append('    option netmask %s;\n' % mask)
                for rng in rangelist:
                    content.append('    range %s %s;\n' % rng)
                content.append('}\n')
            content = ''.join(content)
            todo = write_when_new('/etc/dhcp/dhcpd.conf', content)
            if todo:
                print('change dhcpd.conf')
                to_start['isc-dhcp-server'] = 'restart'
                show.dirty = True
        elif doit:
            unix_cmd('systemctl stop isc-dhcp-server')
            unix_cmd('systemctl disable isc-dhcp-server')
        content = []
        dirty = False
        for section, section_dict in config.items():
            if COMMENT not in section_dict:
                dirty = True
            content.append('[%s]' % section)
            content.append(COMMENT)
            if section == 'DISPLAY':
                if display_update(section_dict):
                    to_start['display'] = 'restart'
            for key, value in section_dict.items():
                content.append('%s=%s' % (key, value))
            content.append('')
        if dirty:
            print(cfgfile)
            print('\n'.join(content))
            #with open(cfgfile, 'w') as f:
            #    f.write('\n'.join(content))
    except Exception as e:
        print('ERROR: can not handle %s %s: %r' % (main_info['hostname'], ifname, e))
        raise
        return False

    reload_systemd = False
    for service, service_func in SERVICES.items():
        section = service.upper()
        section_dict = config.get(section, {})
        servicecfg = service_func(**section_dict)
        result = unix_cmd('systemctl show -p WantedBy -p ActiveState %s' % service, True)
        active = False
        enabled = False
        for line in result.split('\n'):
            if line.startswith('WantedBy=m'):
                enabled = True
            elif line.strip() == 'ActiveState=active':
                active = True
        if servicecfg is None:
            if active:
                unix_cmd('systemctl stop %s' % service)
                show.dirty = True
            if enabled:
                unix_cmd('systemctl disable %s' % service)
                show.dirty = True
            if service == 'router' and active or enabled:
                if doit:
                     shutil.copy(join(TOOLS, 'nftables.conf'), '/etc/nftables.conf')
                else:
                     print('cp nftables.conf /etc/nftables.conf')
                unix_cmd('systemctl restart nftables')
        else:
            if not enabled:
                to_start[service] = 'enable'
            elif not active:
                to_start[service] = 'restart'
        if write_when_new('/etc/systemd/system/%s.service' % service, servicecfg):
            show.dirty = True
            reload_systemd = True
            if servicecfg and to_start.get('service') is None:
                to_start[service] = 'restart'

    pip()
    if reload_systemd:
        unix_cmd('systemctl daemon-reload')
    for service, action in to_start.items():
        show.dirty = True
        if action == 'if_restart':
            unix_cmd('ifdown %s' % service)
    for service, action in to_start.items():
        if action == 'if_restart':
            unix_cmd('ifup %s' % service)
        else:
            if action == 'restart':
                unix_cmd('systemctl restart %s' % service)
            unix_cmd('systemctl enable %s' % service)
    result = [f'config file:\n  {cfgfile}']
    for section, section_dict in config.items():
        result.append(section)
        for key, value in section_dict.items():
            result.append(f'  {key} = {value}')
    result.append('')
    return '\n'.join(result)


more_info = False
doit = False
print(' ')
show = Show()
walk(show)
result = handle_config()

if not result:
    print('fix first above errors')
else:
    if show.dirty:
        print('---')
        answer = input('enter "y(es)" to do above or "m(ore)" for more info: ')
        if not answer:
            print('cancel')
        elif 'yes'.startswith(answer.lower()):
            doit = True
            handle_config()
            walk(Do())
            with open(f'{TOOLS}/current', 'w') as f:
                f.write(result)
        elif 'more'.startswith(answer.lower()):
            more_info = True
            walk(show)
            result = handle_config()
    else:
        print('nothing to do')