#!/usr/bin/env python
# This file is part of Xpra.
# Copyright (C) 2014-2019 Antoine Martin <antoine@xpra.org>
# Xpra is released under the terms of the GNU GPL v2, or, at your option, any
# later version. See the file COPYING for details.

#default implementation using pycups
import sys
import os
import time
from subprocess import PIPE, Popen
import shlex
from threading import Lock
import cups

from xpra.os_util import OSX, PYTHON3, bytestostr
from xpra.util import engs, envint, envbool, parse_simple_dict
from xpra.log import Logger

log = Logger("printing")

SIMULATE_PRINT_FAILURE = envint("XPRA_SIMULATE_PRINT_FAILURE")

RAW_MODE = envbool("XPRA_PRINTER_RAW", False)
GENERIC = envbool("XPRA_PRINTERS_GENERIC", True)
FORWARDER_TMPDIR = os.environ.get("XPRA_FORWARDER_TMPDIR", os.environ.get("TMPDIR", "/tmp"))
#the mimetype to use for clients that do not specify one
#(older clients just assumed postscript)
DEFAULT_MIMETYPE = os.environ.get("XPRA_PRINTER_DEFAULT_MIMETYPE", "application/postscript")

LPADMIN = "lpadmin"
LPINFO = "lpinfo"
ADD_OPTIONS = ["-E", "-o printer-is-shared=false", "-u allow:$USER"]

FORWARDER_BACKEND = "xpraforwarder"

SKIPPED_PRINTERS = os.environ.get("XPRA_SKIPPED_PRINTERS", "Cups-PDF").split(",")
CUPS_OPTIONS_WHITELIST = os.environ.get("XPRA_CUPS_OPTIONS_WHITELIST", "Resolution,PageSize").split(",")

#PRINTER_PREFIX = "Xpra:"
ADD_LOCAL_PRINTERS = envbool("XPRA_ADD_LOCAL_PRINTERS", False)
PRINTER_PREFIX = ""
if ADD_LOCAL_PRINTERS:
    #this prevents problems where we end up deleting local printers!
    PRINTER_PREFIX = "Xpra:"
PRINTER_PREFIX = os.environ.get("XPRA_PRINTER_PREFIX", PRINTER_PREFIX)

DEFAULT_CUPS_DBUS = int(not OSX)
CUPS_DBUS = envint("XPRA_CUPS_DBUS", DEFAULT_CUPS_DBUS)
POLLING_DELAY = envint("XPRA_CUPS_POLLING_DELAY", 60)
log("pycups settings: DEFAULT_CUPS_DBUS=%s, CUPS_DBUS=%s, POLLING_DELAY=%s",
    DEFAULT_CUPS_DBUS, CUPS_DBUS, POLLING_DELAY)
log("pycups settings: PRINTER_PREFIX=%s, ADD_LOCAL_PRINTERS=%s",
    PRINTER_PREFIX, ADD_LOCAL_PRINTERS)
log("pycups settings: FORWARDER_TMPDIR=%s", FORWARDER_TMPDIR)
log("pycups settings: SKIPPED_PRINTERS=%s", SKIPPED_PRINTERS)

MIMETYPE_TO_PRINTER = {
    "application/postscript"    : "Generic PostScript Printer",
    "application/pdf"           : "Generic PDF Printer",
    }
MIMETYPE_TO_PPD = {
    "application/postscript"    : "CUPS-PDF.ppd",
    "application/pdf"           : "Generic-PDF_Printer-PDF.ppd",
    }


dco = os.environ.get("XPRA_DEFAULT_CUPS_OPTIONS", "fit-to-page=True")
DEFAULT_CUPS_OPTIONS = parse_simple_dict(dco)
log("DEFAULT_CUPS_OPTIONS=%s", DEFAULT_CUPS_OPTIONS)


#allows us to inject the lpadmin and lpinfo commands from the config file
def set_lpadmin_command(lpadmin):
    global LPADMIN
    LPADMIN = lpadmin

def set_add_printer_options(options):
    global ADD_OPTIONS
    ADD_OPTIONS = options

def set_lpinfo_command(lpinfo):
    global LPINFO
    LPINFO = lpinfo


def find_ppd_file(short_name, filename):
    ev = os.environ.get("XPRA_%s_PPD" % short_name)
    if ev and os.path.exists(ev):
        log("using environment override for %s ppd file: %s", short_name, ev)
        return ev
    paths = []
    for p in os.environ.get("XDG_DATA_DIRS", "/usr/local/share:/usr/share").split(":"):
        if os.path.exists(p) and os.path.isdir(p):
            paths.append(os.path.join(p, "cups", "model"))      #used on Fedora and others
            paths.append(os.path.join(p, "ppd", "cups-pdf"))    #used on Fedora and others
            paths.append(os.path.join(p, "ppd", "cupsfilters"))
    log("find ppd file: paths=%s", paths)
    for p in paths:
        f = os.path.join(p, filename)
        if os.path.exists(f) and os.path.isfile(f):
            return f
    log("cannot find %s in %s", filename, paths)
    return None


def get_lpinfo_drv(make_and_model):
    command = shlex.split(LPINFO)+["--make-and-model", make_and_model, "-m"]
    def preexec():
        os.setsid()
    log("get_lpinfo_drv(%s) command=%s", make_and_model, command)
    try:
        proc = Popen(command, stdout=PIPE, stderr=PIPE, close_fds=True, preexec_fn=preexec)
    except Exception as e:
        log("get_lp_info_drv(%s) lpinfo command %s failed", make_and_model, command, exc_info=True)
        log.error("Error: lpinfo command failed to run")
        log.error(" %s", e)
        log.error(" command used: '%s'", " ".join(command))
        return None
    #use the global child reaper to make sure this doesn't end up as a zombie
    from xpra.child_reaper import getChildReaper
    from xpra.util import nonl
    cr = getChildReaper()
    cr.add_process(proc, "lpinfo", command, ignore=True, forget=True)
    from xpra.make_thread import start_thread
    def watch_lpinfo():
        #give it 15 seconds to run:
        for _ in range(15):
            if proc.poll() is not None:
                return      #finished already
            time.sleep(1)
        if proc.poll() is not None:
            return
        log.warn("Warning: lpinfo command is taking too long,")
        log.warn(" is the cups server running?")
        try:
            proc.terminate()
        except Exception as e:
            log("%s.terminate()", proc, exc_info=True)
            log.error("Error: failed to terminate lpinfo command")
            log.error(" %s", e)
    start_thread(watch_lpinfo, "lpinfo watcher", daemon=True)
    out, err = proc.communicate()
    if proc.wait()!=0:
        log.warn("Warning: lpinfo command failed and returned %s", proc.returncode)
        log.warn(" command used: '%s'", " ".join(command))
        return None
    if PYTHON3:
        try:
            out = out.decode()
        except:
            out = str(out)
    log("lpinfo out=%s", nonl(out))
    log("lpinfo err=%s", nonl(err))
    if err:
        log.warn("Warning: lpinfo command produced some warnings:")
        log.warn(" '%s'", nonl(err))
    for line in out.splitlines():
        if line.startswith("drv://"):
            return line.split(" ")[0]
    return None


UNPROBED_PRINTER_DEFS = {}
def add_printer_def(mimetype, definition):
    if definition.startswith("drv://"):
        UNPROBED_PRINTER_DEFS[mimetype] = ["-m", definition]
    elif definition.lower().endswith("ppd"):
        if os.path.exists(definition):
            UNPROBED_PRINTER_DEFS[mimetype] = ["-P", definition]
        else:
            log.warn("Warning: ppd file '%s' does not exist", definition)
    else:
        log.warn("Warning: invalid printer definition for %s:", mimetype)
        log.warn(" '%s' is not a valid driver or ppd file", definition)


PRINTER_DEF = None
PRINTER_DEF_LOCK = Lock()
def get_printer_definitions():
    global PRINTER_DEF, PRINTER_DEF_LOCK, UNPROBED_PRINTER_DEFS, MIMETYPE_TO_PRINTER
    with PRINTER_DEF_LOCK:
        if PRINTER_DEF is not None:
            return PRINTER_DEF
        log("get_printer_definitions() UNPROBED_PRINTER_DEFS=%s, GENERIC=%s", UNPROBED_PRINTER_DEFS, GENERIC)
        from xpra.platform.printing import get_mimetypes
        mimetypes = get_mimetypes()
        #first add the user-supplied definitions:
        PRINTER_DEF = UNPROBED_PRINTER_DEFS.copy()
        #raw mode if supported:
        if RAW_MODE:
            PRINTER_DEF["raw"] = ["-o", "raw"]
        #now probe for generic printers via lpinfo:
        if GENERIC:
            for mt in mimetypes:
                if mt in PRINTER_DEF:
                    continue    #we have a pre-defined one already
                x = MIMETYPE_TO_PRINTER.get(mt)
                if not x:
                    log.warn("Warning: unknown mimetype '%s', cannot find printer definition", mt)
                    continue
                drv = get_lpinfo_drv(x)
                if drv:
                    #ie: ["-m", "drv:///sample.drv/generic.ppd"]
                    PRINTER_DEF[mt] = ["-m", drv]
        #fallback to locating ppd files:
        for mt in mimetypes:
            if mt in PRINTER_DEF:
                continue        #we have a generic or pre-defined one already
            x = MIMETYPE_TO_PPD.get(mt)
            if not x:
                log.warn("Warning: unknown mimetype '%s', cannot find corresponding PPD file", mt)
                continue
            f = find_ppd_file(mt.replace("application/", "").upper(), x)
            if f:
                #ie: ["-P", "/usr/share/cups/model/Generic-PDF_Printer-PDF.ppd"]
                PRINTER_DEF[mt] = ["-P", f]
        log("pycups settings: PRINTER_DEF=%s", PRINTER_DEF)
    return PRINTER_DEF

def get_printer_definition(mimetype):
    v = get_printer_definitions().get("application/%s" % mimetype)
    if not v:
        return ""
    if len(v)!=2:
        return ""
    if v[0] not in ("-m", "-P"):
        return ""
    return v[1]     #ie: /usr/share/ppd/cupsfilters/Generic-PDF_Printer-PDF.ppd


def validate_setup():
    #very simple check: at least one ppd file exists
    defs = get_printer_definitions()
    if not defs:
        return False
    return defs


def exec_lpadmin(args, success_cb=None):
    command = shlex.split(LPADMIN)+args
    def preexec():
        os.setsid()
    log("exec_lpadmin(%s) command=%s", args, command)
    proc = Popen(command, close_fds=True, preexec_fn=preexec)
    #use the global child reaper to make sure this doesn't end up as a zombie
    from xpra.child_reaper import getChildReaper
    cr = getChildReaper()
    def check_returncode(_proc_cb):
        returncode = proc.poll()
        log("returncode(%s)=%s", command, returncode)
        if returncode!=0:
            log.warn("lpadmin failed and returned error code: %s", returncode)
            from xpra.platform import get_username
            log.warn(" verify that user '%s' has all the required permissions", get_username())
            log.warn(" for running: '%s'", LPADMIN)
            log.warn(" full command: %s", b" ".join("'%s'" % x for x in command))
        elif success_cb:
            success_cb()
    cr.add_process(proc, "lpadmin", command, ignore=True, forget=True, callback=check_returncode)
    if proc.poll() not in (None, 0):
        raise Exception("lpadmin command '%s' failed and returned %s" % (command, proc.poll()))


def sanitize_name(name):
    import string
    name = name.replace(" ", "-")
    valid_chars = "-_.:%s%s" % (string.ascii_letters, string.digits)
    return ''.join(c for c in name if c in valid_chars)

def add_printer(name, options, info, location, attributes={}, success_cb=None):
    log("add_printer%s", (name, options, info, location, attributes, success_cb))
    mimetypes = options.get("mimetypes", [DEFAULT_MIMETYPE])
    if not mimetypes:
        log.error("Error: no mimetypes specified for printer '%s'", name)
        return
    xpra_printer_name = PRINTER_PREFIX+sanitize_name(name)
    if xpra_printer_name in get_all_printers():
        log.warn("Warning: not adding duplicate printer '%s'", name)
        return
    #find a matching definition:
    mimetype, printer_def = None, None
    defs = get_printer_definitions()
    for mt in mimetypes:
        printer_def = defs.get(mt)
        if printer_def:
            log("using printer definition '%s' for %s", printer_def, mt)
            #ie: printer_def = ["-P", "/path/to/CUPS-PDF.ppd"]
            mimetype = mt
            attributes["mimetype"] = mimetype
            break
    if not printer_def:
        log.error("Error: cannot add printer '%s':", name)
        log.error(" the printing system does not support %s", " or ".join(mimetypes))
        return
    if PYTHON3:
        from urllib.parse import urlencode      #@UnresolvedImport @UnusedImport
    else:
        from urllib import urlencode            #@Reimport
    command = [
               "-p", xpra_printer_name,
               "-v", FORWARDER_BACKEND+":"+FORWARDER_TMPDIR+"?"+urlencode(attributes),
               "-D", info,
               "-L", location,
               ]
    if ADD_OPTIONS:
        #ie: ["-E", "-o printer-is-shared=false", "-u allow:$USER"]
        for opt in ADD_OPTIONS:
            parts = shlex.split(opt)    #ie: "-u allow:$USER" -> ["-u", "allow:$USER"]
            for part in parts:          #ie: "allow:$USER"
                command.append(os.path.expandvars(part))
    command += printer_def
    #add attributes:
    log("pycups_printing adding printer: %s", command)
    exec_lpadmin(command, success_cb=success_cb)

def remove_printer(name):
    log("remove_printer(%s)", name)
    exec_lpadmin(["-x", PRINTER_PREFIX+sanitize_name(name)])


dbus_init = None
printers_modified_callback = None
DBUS_PATH="/com/redhat/PrinterSpooler"
DBUS_IFACE="com.redhat.PrinterSpooler"
def handle_dbus_signal(*args):
    global printers_modified_callback
    log("handle_dbus_signal(%s) printers_modified_callback=%s", args, printers_modified_callback)
    if printers_modified_callback:
        printers_modified_callback()

def init_dbus_listener():
    if not CUPS_DBUS:
        return False
    global dbus_init
    log("init_dbus_listener() dbus_init=%s", dbus_init)
    if dbus_init is None:
        try:
            from xpra.dbus.common import init_system_bus
            system_bus = init_system_bus()
            log("system bus: %s", system_bus)
            sig_match = system_bus.add_signal_receiver(handle_dbus_signal, path=DBUS_PATH, dbus_interface=DBUS_IFACE)
            log("system_bus.add_signal_receiver(..)=%s", sig_match)
            dbus_init = True
        except ImportError as e:
            log.warn("Warning: cannot watch for printer device changes,")
            log.warn(" the dbus bindings seem to be missing:")
            log.warn(" %s", e)
            dbus_init = False
        except Exception:
            if OSX:
                log("no dbus on osx")
            else:
                log.error("failed to initialize dbus cups event listener", exc_info=True)
            dbus_init = False
    return dbus_init

def check_printers():
    global printers_modified_callback
    #we don't actually check anything here and just
    #fire the callback every time, relying in client_base
    #to notice that nothing has changed and avoid sending the same printers to the server
    log("check_printers() printers_modified_callback=%s", printers_modified_callback)
    if printers_modified_callback:
        printers_modified_callback()
    schedule_polling_timer()

_polling_timer = None
def schedule_polling_timer():
    #fallback to polling:
    cancel_polling_timer()
    from threading import Timer
    global _polling_timer
    _polling_timer = Timer(POLLING_DELAY, check_printers)
    _polling_timer.start()
    log("schedule_polling_timer() timer=%s", _polling_timer)

def cancel_polling_timer():
    global _polling_timer
    pt = _polling_timer
    log("cancel_polling_timer() timer=%s", pt)
    if pt:
        try:
            _polling_timer = None
            pt.cancel()
        except:
            pass

def init_printing(callback=None):
    global printers_modified_callback
    log("init_printing(%s) printers_modified_callback=%s", callback, printers_modified_callback)
    printers_modified_callback = callback
    if not init_dbus_listener():
        log("init_printing(%s) will use polling", callback)
        schedule_polling_timer()

def cleanup_printing():
    cancel_polling_timer()


def get_printers():
    all_printers = get_all_printers()
    return dict((k,v) for k,v in all_printers.items() if k not in SKIPPED_PRINTERS)

def get_all_printers():
    conn = cups.Connection()
    printers = conn.getPrinters()
    log("pycups.get_all_printers()=%s", printers)
    return printers

def get_default_printer():
    conn = cups.Connection()
    return conn.getDefault()

def get_printer_attributes(name):
    conn = cups.Connection()
    return conn.getPrinterAttributes(name)


def print_files(printer, filenames, title, options):
    if printer not in get_printers():
        raise Exception("invalid printer: '%s'" % printer)
    log("pycups.print_files%s", (printer, filenames, title, options))
    actual_options = DEFAULT_CUPS_OPTIONS.copy()
    s = bytestostr
    used_options = dict((s(k),s(v)) for k,v in options.items() if s(k) in CUPS_OPTIONS_WHITELIST)
    unused_options = dict((s(k),s(v)) for k,v in options.items() if s(k) not in CUPS_OPTIONS_WHITELIST)
    log("used options=%s", used_options)
    log("unused options=%s", unused_options)
    actual_options.update(used_options)
    if SIMULATE_PRINT_FAILURE:
        log.warn("Warning: simulating print failure")
        conn = None
        printpid = -1
    else:
        conn = cups.Connection()
        log("calling printFiles on %s", conn)
        printpid = conn.printFiles(printer, filenames, title, actual_options)
    if printpid<=0:
        log.error("Error: pycups printing on '%s' failed for file%s", printer, engs(filenames))
        for f in filenames:
            log.error(" %s", f)
        log.error(" using cups server connection: %s", conn)
        if actual_options:
            log.error(" printer options:")
            for k,v in actual_options.items():
                log.error("  %-24s : %s", k, v)
    else:
        log("pycups %s.printFiles%s=%s", conn, (printer, filenames, title, actual_options), printpid)
    return printpid

def printing_finished(printpid):
    conn = cups.Connection()
    f = conn.getJobs().get(printpid, None) is None
    log("pycups.printing_finished(%s)=%s", printpid, f)
    return f


PRINTER_STATE = {
                3   : "idle",
                4   : "printing",
                5   : "stopped",
                 }


def get_info():
    from xpra.platform.printing import get_mimetypes, DEFAULT_MIMETYPES
    return {"mimetypes"         : {""           : get_mimetypes(),
                                   "default"    : DEFAULT_MIMETYPES,
                                   "printers"   : MIMETYPE_TO_PRINTER,
                                   "ppd"        : MIMETYPE_TO_PPD},
            "mimetype"          : {"default"    : DEFAULT_MIMETYPE},
            "simulate-failure"  : SIMULATE_PRINT_FAILURE,
            "raw-mode"          : RAW_MODE,
            "generic"           : GENERIC,
            "tmpdir"            : FORWARDER_TMPDIR,
            "lpadmin"           : LPADMIN,
            "lpinfo"            : LPINFO,
            "forwarder"         : FORWARDER_BACKEND,
            "skipped-printers"  : SKIPPED_PRINTERS,
            "add-local-printers": ADD_LOCAL_PRINTERS,
            "printer-prefix"    : PRINTER_PREFIX,
            "cups-dbus"         : {""           : CUPS_DBUS,
                                   "default"    : DEFAULT_CUPS_DBUS,
                                   "poll-delay" : POLLING_DELAY},
            "cups.default-options"  : DEFAULT_CUPS_OPTIONS,
            "printers"          : {""           : get_printer_definitions(),
                                   "predefined" : UNPROBED_PRINTER_DEFS},
            }


def main():
    for arg in list(sys.argv):
        if arg in ("-v", "--verbose"):
            from xpra.log import add_debug_category, enable_debug_for
            add_debug_category("printing")
            enable_debug_for("printing")
            sys.argv.remove(arg)

    from xpra.platform import program_context
    from xpra.log import enable_color
    with program_context("PyCUPS Printing"):
        enable_color()
        validate_setup()
        log.info("")
        log.info("printer definitions:")
        for k,v in get_printer_definitions().items():
            log.info("* %-32s: %s", k, v)
        log.info("")
        log.info("local printers:")
        try:
            printers = get_printers()
        except RuntimeError as e:
            log.error("Error accessing the printing system")
            log.error(" %s", e)
        else:
            for k,d in get_all_printers().items():
                log.info("* %s%s", k, [" (NOT EXPORTED)", ""][int(k in printers)])
                for pk, pv in d.items():
                    if pk=="printer-state" and pv in PRINTER_STATE:
                        pv = "%s (%s)" % (pv, PRINTER_STATE.get(pv))
                    log.info("    %-32s: %s", pk, pv)


if __name__ == "__main__":
    main()
