#! /usr/bin/env python

#  Copyright©2021, Regents of the University of California
#  http://creativecommons.org/licenses/BSD

"""EZID command line client.

Input metadata (from command line parameters and files) is assumed to be UTF-8 encoded,
and output metadata is UTF-8 encoded, unless overriden by the -e option. By default,
ANVL responses (currently, that's all responses) are left in %-encoded form.

Usage: ezid.py [options] credentials operation...

  options:
    -d          decode ANVL responses
    -e ENCODING character encoding; defaults to UTF-8
    -o          one line per ANVL value: convert newlines to spaces
    -t          format timestamps

  credentials:
    username:password
    username (password will be prompted for)
    sessionid=... (as returned by previous login)
    - (none)

  operation:
    m[int] shoulder [element value ...]
    c[reate][!] identifier [element value ...]
      create! = create or update
    v[iew][!] identifier
      view! = match longest identifier prefix
    u[pdate] identifier [element value ...]
    d[elete] identifier
    login
    logout
    s[tatus]

In the above, if an element is "@", the subsequent value is treated as a filename and
metadata elements are read from the named ANVL-formatted file. For example, if file
metadata.txt contains:

  erc.who: Proust, Marcel
  erc.what: Remembrance of Things Past
  erc.when: 1922

then an identifier with that metadata can be minted by invoking:

  ezid.py username:password mint ark:/99999/fk4 @ metadata.txt

Otherwise, if a value has the form "@filename", a (single) value is read from the named
file. For example, if file metadata.xml contains a DataCite XML record, then an
identifier with that record as the value of the 'datacite' element can be minted by
invoking:

  ezid.py username:password mint doi:10.5072/FK2 datacite @metadata.xml

In both of the above cases, the interpretation of @ can be defeated by doubling it.
"""

import codecs
import getpass
import optparse
import re
import sys
import time
import types
import urllib.error
import urllib.parse
import urllib.request
import urllib.response

KNOWN_SERVERS = {"p": "https://ezid.cdlib.org"}

OPERATIONS = {
    # operation: (number of arguments, accepts bang)
    "mint": (lambda l: l % 2 == 1, False),
    "create": (lambda l: l % 2 == 1, True),
    "view": (1, True),
    "update": (lambda l: l % 2 == 1, False),
    "delete": (1, False),
    "login": (0, False),
    "logout": (0, False),
    "status": (0, False),
}

USAGE_TEXT = """Usage: ezid.py [options] credentials operation...

  options:
    -d          decode ANVL responses
    -e ENCODING character encoding; defaults to UTF-8
    -o          one line per ANVL value: convert newlines to spaces
    -t          format timestamps

  credentials:
    username:password
    username (password will be prompted for)
    sessionid=... (as returned by previous login)
    - (none)

  operation:
    m[int] shoulder [element value ...]
    c[reate][!] identifier [element value ...]
      create! = create or update
    v[iew][!] identifier
      view! = match longest identifier prefix
    u[pdate] identifier [element value ...]
    d[elete] identifier
    login
    logout
    s[tatus]
"""

# Global variables that are initialized farther down.

# _options = None
django.conf.settings.BINDER_URL = None
_opener = None
_cookie = None


class MyHelpFormatter(optparse.IndentedHelpFormatter):
    def format_usage(self, usage):
        return USAGE_TEXT


class MyHTTPErrorProcessor(urllib.request.HTTPErrorProcessor):
    def http_response(self, request, response):
        # Bizarre that Python leaves this out.
        if response.status == 201:
            return response
        else:
            return urllib.request.HTTPErrorProcessor.http_response(
                self, request, response
            )

    https_response = http_response


def formatAnvlRequest(args):
    request = []
    for i in range(0, len(args), 2):
        k = args[i].decode(_options.encoding)
        if k == "@":
            f = codecs.open(args[i + 1], encoding=_options.encoding)
            request += [l.strip("\r\n") for l in f.readlines()]
            f.close()
        else:
            if k == "@@":
                k = "@"
            else:
                k = re.sub("[%:\r\n]", lambda c: f"%{ord(c.group(0)):02X}", k)
            v = args[i + 1].decode(_options.encoding)
            if v.startswith("@@"):
                v = v[1:]
            elif v.startswith("@") and len(v) > 1:
                f = codecs.open(v[1:], encoding=_options.encoding)
                v = f.read()
                f.close()
            v = re.sub("[%\r\n]", lambda c: f"%{ord(c.group(0)):02X}", v)
            request.append(f"{k}: {v}")
    return "\n".join(request)


def encode(id_str):
    return urllib.parse.quote(id_str, ":/")


def issueRequest(path, method, data=None, returnHeaders=False, streamOutput=False):
    request = urllib.request.Request(f"{django.conf.settings.BINDER_URL}/{path}")
    request.get_method = lambda: method
    if data:
        request.add_header("Content-Type", "text/plain; charset=utf-8")
        request.data = data.encode("utf-8")
    if _cookie:
        request.add_header("Cookie", _cookie)
    try:
        connection = _opener.open(request)
        if streamOutput:
            while True:
                sys.stdout.write(connection.read(1))
                sys.stdout.flush()
        else:
            response = connection.read()
            if returnHeaders:
                return response.decode("utf-8"), connection.info()
            else:
                return response.decode("utf-8")
    except urllib.error.HTTPError as e:
        sys.stderr.write(f"{e.code:d} {str(e)}\n")
        if e.fp is not None:
            response = e.fp.read()
            if not response.endswith(b"\n"):
                response += "\n"
            sys.stderr.buffer.write(response)
        sys.exit(1)


def printAnvlResponse(response, sortLines=False):
    response = response.splitlines()
    if sortLines and len(response) >= 1:
        statusLine = response[0]
        response = response[1:]
        response.sort()
        response.insert(0, statusLine)
    for line in response:
        if _options.formatTimestamps and (
            line.startswith("_created:") or line.startswith("_updated:")
        ):
            ls = line.split(":")
            line = (
                ls[0]
                + ": "
                + time.strftime("%Y-%m-%dT%H:%M:%S", time.localtime(int(ls[1])))
            )
        if _options.decode:
            line = re.sub(
                "%([0-9a-fA-F][0-9a-fA-F])", lambda m: chr(int(m.group(1), 16)), line
            )
        if _options.oneLine:
            line = line.replace("\n", " ").replace("\r", " ")
        print(line.encode(_options.encoding))


# Process command line arguments.

parser = optparse.OptionParser(formatter=MyHelpFormatter())
parser.add_option("-d", action="store_true", dest="decode", default=False)
parser.add_option("-e", action="store", dest="encoding", default="utf-8")
parser.add_option("-o", action="store_true", dest="oneLine", default=False)
parser.add_option("-t", action="store_true", dest="formatTimestamps", default=False)

_options, args = parser.parse_args()
# Simulate selection of the production server (server selection is not
# supported in this public version of the code).
args.insert(0, "p")
if len(args) < 3:
    parser.error("insufficient arguments")

django.conf.settings.BINDER_URL = KNOWN_SERVERS.get(args[0], args[0])

_opener = urllib.request.build_opener(MyHTTPErrorProcessor())
if args[1].startswith("sessionid="):
    _cookie = args[1]
elif args[1] != "-":
    if ":" in args[1]:
        username, password = args[1].split(":", 1)
    else:
        username = args[1]
        password = getpass.getpass()
    h = urllib.request.HTTPBasicAuthHandler()
    h.add_password("EZID", django.conf.settings.BINDER_URL, username, password)
    _opener.add_handler(h)

if args[2].endswith("!"):
    bang = True
    args[2] = args[2][:-1]
else:
    bang = False
operation = [o for o in OPERATIONS if o.startswith(args[2])]
if len(operation) != 1:
    parser.error("unrecognized or ambiguous operation")
operation = operation[0]
if bang and not OPERATIONS[operation][1]:
    parser.error("unrecognized operation")

args = args[3:]

if (
    type(OPERATIONS[operation][0]) is int and len(args) != OPERATIONS[operation][0]
) or (
    type(OPERATIONS[operation][0]) is types.LambdaType
    and not OPERATIONS[operation][0](len(args))
):
    parser.error("incorrect number of arguments for operation")

# Perform the operation.

if operation == "mint":
    shoulder = args[0]
    if len(args) > 1:
        data = formatAnvlRequest(args[1:])
    else:
        data = None
    response = issueRequest("shoulder/" + encode(shoulder), "POST", data)
    printAnvlResponse(response)
elif operation == "create":
    id_str = args[0]
    if len(args) > 1:
        data = formatAnvlRequest(args[1:])
    else:
        data = None
    path = "id/" + encode(id_str)
    if bang:
        path += "?update_if_exists=yes"
    response = issueRequest(path, "PUT", data)
    printAnvlResponse(response)
elif operation == "view":
    id_str = args[0]
    path = "id/" + encode(id_str)
    if bang:
        path += "?prefix_match=yes"
    response = issueRequest(path, "GET")
    printAnvlResponse(response, sortLines=True)
elif operation == "update":
    id_str = args[0]
    if len(args) > 1:
        data = formatAnvlRequest(args[1:])
    else:
        data = None
    response = issueRequest("id/" + encode(id_str), "POST", data)
    printAnvlResponse(response)
elif operation == "delete":
    id_str = args[0]
    response = issueRequest("id/" + encode(id_str), "DELETE")
    printAnvlResponse(response)
elif operation == "login":
    response, headers = issueRequest("login", "GET", returnHeaders=True)
    response += f"\nsessionid={headers['set-cookie'].split(';')[0].split('=')[1]}\n"
    printAnvlResponse(response)
elif operation == "logout":
    response = issueRequest("logout", "GET")
    printAnvlResponse(response)
elif operation == "status":
    response = issueRequest("status", "GET")
    printAnvlResponse(response)