#!/usr/bin/python

# Copyright (c) 2013, Serge van Ginderachter <serge@vanginderachter.be>
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later

from __future__ import annotations

DOCUMENTATION = r"""
module: open_iscsi
author:
  - Serge van Ginderachter (@srvg)
short_description: Manage iSCSI targets with Open-iSCSI
description:
  - Discover targets on given portal, (dis)connect targets, mark targets to manually or auto start, return device nodes of
    connected targets.
requirements:
  - open_iscsi library and tools (iscsiadm)
extends_documentation_fragment:
  - community.general.attributes
attributes:
  check_mode:
    support: full
  diff_mode:
    support: none
options:
  portal:
    description:
      - The domain name or IP address of the iSCSI target.
    type: str
    aliases: [ip]
  port:
    description:
      - The port on which the iSCSI target process listens.
    type: str
    default: '3260'
  target:
    description:
      - The iSCSI target name.
    type: str
    aliases: [name, targetname]
  login:
    description:
      - Whether the target node should be connected.
      - When O(target) is omitted, it logins to all available.
    type: bool
    aliases: [state]
  node_auth:
    description:
      - The value for C(node.session.auth.authmethod).
    type: str
    default: CHAP
  node_user:
    description:
      - The value for C(node.session.auth.username).
    type: str
  node_pass:
    description:
      - The value for C(node.session.auth.password).
    type: str
  node_user_in:
    description:
      - The value for C(node.session.auth.username_in).
    type: str
    version_added: 3.8.0
  node_pass_in:
    description:
      - The value for C(node.session.auth.password_in).
    type: str
    version_added: 3.8.0
  auto_node_startup:
    description:
      - Whether the target node should be automatically connected at startup.
    type: bool
    aliases: [automatic]
  auto_portal_startup:
    description:
      - Whether the target node portal should be automatically connected at startup.
    type: bool
    version_added: 3.2.0
  discover:
    description:
      - Whether the list of target nodes on the portal should be (re)discovered and added to the persistent iSCSI database.
      - Keep in mind that C(iscsiadm) discovery resets configuration, like C(node.startup) to manual, hence combined with
        O(auto_node_startup=true) always returns a changed state.
    type: bool
    default: false
  show_nodes:
    description:
      - Whether the list of nodes in the persistent iSCSI database should be returned by the module.
    type: bool
    default: false
  rescan:
    description:
      - Rescan an established session for discovering new targets.
      - When O(target) is omitted, it rescans all sessions.
    type: bool
    default: false
    version_added: 4.1.0
"""

EXAMPLES = r"""
- name: Perform a discovery on sun.com and show available target nodes
  community.general.open_iscsi:
    show_nodes: true
    discover: true
    portal: sun.com

- name: Perform a discovery on 10.1.2.3 and show available target nodes
  community.general.open_iscsi:
    show_nodes: true
    discover: true
    ip: 10.1.2.3

- name: Discover targets on portal and login to the ones available
  community.general.open_iscsi:
    portal: '{{ iscsi_target }}'
    login: true
    discover: true

- name: Connect to the named target, after updating the local persistent database (cache)
  community.general.open_iscsi:
    login: true
    target: iqn.1986-03.com.sun:02:f8c1f9e0-c3ec-ec84-c9c9-8bfb0cd5de3d

- name: Disconnect from the cached named target
  community.general.open_iscsi:
    login: false
    target: iqn.1986-03.com.sun:02:f8c1f9e0-c3ec-ec84-c9c9-8bfb0cd5de3d

- name: Override and disable automatic portal login on specific portal
  community.general.open_iscsi:
    login: false
    portal: 10.1.1.250
    auto_portal_startup: false
    target: iqn.1986-03.com.sun:02:f8c1f9e0-c3ec-ec84-c9c9-8bfb0cd5de3d

- name: Rescan one or all established sessions to discover new targets (omit target for all sessions)
  community.general.open_iscsi:
    rescan: true
    target: iqn.1986-03.com.sun:02:f8c1f9e0-c3ec-ec84-c9c9-8bfb0cd5de3d
"""

import glob
import os
import re
import socket
import time

from ansible.module_utils.basic import AnsibleModule

ISCSIADM = "iscsiadm"
iscsiadm_cmd = None


def compare_nodelists(l1, l2):
    l1.sort()
    l2.sort()
    return l1 == l2


def iscsi_get_cached_nodes(module, portal=None):
    cmd = [iscsiadm_cmd, "--mode", "node"]
    rc, out, err = module.run_command(cmd)

    nodes = []
    if rc == 0:
        lines = out.splitlines()
        for line in lines:
            # line format is "ip:port,target_portal_group_tag targetname"
            parts = line.split()
            if len(parts) > 2:
                module.fail_json(msg="error parsing output", cmd=cmd)
            target = parts[1]
            parts = parts[0].split(":")
            target_portal = parts[0]

            if portal is None or portal == target_portal:
                nodes.append(target)

    # older versions of scsiadm don't have nice return codes
    # for newer versions see iscsiadm(8); also usr/iscsiadm.c for details
    # err can contain [N|n]o records...
    elif rc == 21 or (rc == 255 and "o records found" in err):
        pass
    else:
        module.fail_json(cmd=cmd, rc=rc, msg=err)

    return nodes


def iscsi_discover(module, portal, port):
    cmd = [iscsiadm_cmd, "--mode", "discovery", "--type", "sendtargets", "--portal", f"{portal}:{port}"]
    module.run_command(cmd, check_rc=True)


def iscsi_rescan(module, target=None):
    if target is None:
        cmd = [iscsiadm_cmd, "--mode", "session", "--rescan"]
    else:
        cmd = [iscsiadm_cmd, "--mode", "node", "--rescan", "-T", target]
    rc, out, err = module.run_command(cmd)
    return out


def target_loggedon(module, target, portal=None, port=None):
    cmd = [iscsiadm_cmd, "--mode", "session"]
    rc, out, err = module.run_command(cmd)

    if portal is None:
        portal = ""
    if port is None:
        port = ""

    if rc == 0:
        search_re = f"{re.escape(portal)}:{port}.*{re.escape(target)}"
        return re.search(search_re, out) is not None
    elif rc == 21:
        return False
    else:
        module.fail_json(cmd=cmd, rc=rc, msg=err)


def target_login(module, target, check_rc, portal=None, port=None):
    node_auth = module.params["node_auth"]
    node_user = module.params["node_user"]
    node_pass = module.params["node_pass"]
    node_user_in = module.params["node_user_in"]
    node_pass_in = module.params["node_pass_in"]

    if node_user:
        params = [
            ("node.session.auth.authmethod", node_auth),
            ("node.session.auth.username", node_user),
            ("node.session.auth.password", node_pass),
        ]
        for name, value in params:
            cmd = [
                iscsiadm_cmd,
                "--mode",
                "node",
                "--targetname",
                target,
                "--op=update",
                "--name",
                name,
                "--value",
                value,
            ]
            module.run_command(cmd, check_rc=check_rc)

    if node_user_in:
        params = [("node.session.auth.username_in", node_user_in), ("node.session.auth.password_in", node_pass_in)]
        for name, value in params:
            cmd = [
                iscsiadm_cmd,
                "--mode",
                "node",
                "--targetname",
                target,
                "--op=update",
                "--name",
                name,
                "--value",
                value,
            ]
            module.run_command(cmd, check_rc=check_rc)

    cmd = [iscsiadm_cmd, "--mode", "node", "--targetname", target, "--login"]
    if portal is not None and port is not None:
        cmd.append("--portal")
        cmd.append(f"{portal}:{port}")

    rc, out, err = module.run_command(cmd, check_rc=check_rc)
    return rc


def target_logout(module, target):
    cmd = [iscsiadm_cmd, "--mode", "node", "--targetname", target, "--logout"]
    module.run_command(cmd, check_rc=True)


def target_device_node(target):
    # if anyone know a better way to find out which devicenodes get created for
    # a given target...

    devices = glob.glob(f"/dev/disk/by-path/*{target}*")
    devdisks = []
    for dev in devices:
        # exclude partitions
        if "-part" not in dev:
            devdisk = os.path.realpath(dev)
            # only add once (multi-path?)
            if devdisk not in devdisks:
                devdisks.append(devdisk)
    return devdisks


def target_isauto(module, target, portal=None, port=None):
    cmd = [iscsiadm_cmd, "--mode", "node", "--targetname", target]

    if portal is not None and port is not None:
        cmd.append("--portal")
        cmd.append(f"{portal}:{port}")

    dummy, out, dummy = module.run_command(cmd, check_rc=True)

    lines = out.splitlines()
    for line in lines:
        if "node.startup" in line:
            return "automatic" in line
    return False


def target_setauto(module, target, portal=None, port=None):
    cmd = [
        iscsiadm_cmd,
        "--mode",
        "node",
        "--targetname",
        target,
        "--op=update",
        "--name",
        "node.startup",
        "--value",
        "automatic",
    ]

    if portal is not None and port is not None:
        cmd.append("--portal")
        cmd.append(f"{portal}:{port}")

    module.run_command(cmd, check_rc=True)


def target_setmanual(module, target, portal=None, port=None):
    cmd = [
        iscsiadm_cmd,
        "--mode",
        "node",
        "--targetname",
        target,
        "--op=update",
        "--name",
        "node.startup",
        "--value",
        "manual",
    ]

    if portal is not None and port is not None:
        cmd.append("--portal")
        cmd.append(f"{portal}:{port}")

    module.run_command(cmd, check_rc=True)


def main():
    # load ansible module object
    module = AnsibleModule(
        argument_spec=dict(
            # target
            portal=dict(type="str", aliases=["ip"]),
            port=dict(type="str", default="3260"),
            target=dict(type="str", aliases=["name", "targetname"]),
            node_auth=dict(type="str", default="CHAP"),
            node_user=dict(type="str"),
            node_pass=dict(type="str", no_log=True),
            node_user_in=dict(type="str"),
            node_pass_in=dict(type="str", no_log=True),
            # actions
            login=dict(type="bool", aliases=["state"]),
            auto_node_startup=dict(type="bool", aliases=["automatic"]),
            auto_portal_startup=dict(type="bool"),
            discover=dict(type="bool", default=False),
            show_nodes=dict(type="bool", default=False),
            rescan=dict(type="bool", default=False),
        ),
        required_together=[["node_user", "node_pass"], ["node_user_in", "node_pass_in"]],
        required_if=[
            ("discover", True, ["portal"]),
            ("auto_node_startup", True, ["target"]),
            ("auto_portal_startup", True, ["target"]),
        ],
        supports_check_mode=True,
    )

    global iscsiadm_cmd
    iscsiadm_cmd = module.get_bin_path("iscsiadm", required=True)

    # parameters
    portal = module.params["portal"]
    if portal:
        try:
            portal = socket.getaddrinfo(portal, None)[0][4][0]
        except socket.gaierror:
            module.fail_json(msg="Portal address is incorrect")

    target = module.params["target"]
    port = module.params["port"]
    login = module.params["login"]
    automatic = module.params["auto_node_startup"]
    automatic_portal = module.params["auto_portal_startup"]
    discover = module.params["discover"]
    show_nodes = module.params["show_nodes"]
    rescan = module.params["rescan"]

    check = module.check_mode

    cached = iscsi_get_cached_nodes(module, portal)

    # return json dict
    result = {"changed": False}
    login_to_all_nodes = False
    check_rc = True

    if discover:
        if check:
            nodes = cached
        else:
            iscsi_discover(module, portal, port)
            nodes = iscsi_get_cached_nodes(module, portal)
        if not compare_nodelists(cached, nodes):
            result["changed"] |= True
            result["cache_updated"] = True
    else:
        nodes = cached

    if login is not None or automatic is not None:
        if target is None:
            if len(nodes) > 1:
                # Disable strict return code checking if there are multiple targets
                # That will allow to skip target where we have no rights to login
                login_to_all_nodes = True
                check_rc = False
        else:
            # check given target is in cache
            check_target = False
            for node in nodes:
                if node == target:
                    check_target = True
                    break
            if not check_target:
                module.fail_json(msg="Specified target not found")

    if show_nodes:
        result["nodes"] = nodes

    if login is not None:
        if login_to_all_nodes:
            result["devicenodes"] = []
            for index_target in nodes:
                loggedon = target_loggedon(module, index_target, portal, port)
                if (login and loggedon) or (not login and not loggedon):
                    result["changed"] |= False
                    if login:
                        result["devicenodes"] += target_device_node(index_target)
                elif not check:
                    if login:
                        login_result = target_login(module, index_target, check_rc, portal, port)
                        # give udev some time
                        time.sleep(1)
                        result["devicenodes"] += target_device_node(index_target)
                    else:
                        target_logout(module, index_target)
                    # Check if there are multiple targets on a single portal and
                    # do not mark the task changed if host could not login to one of them
                    if len(nodes) > 1 and login_result == 24:
                        result["changed"] |= False
                        result["connection_changed"] = False
                    else:
                        result["changed"] |= True
                        result["connection_changed"] = True
                else:
                    result["changed"] |= True
                    result["connection_changed"] = True
        else:
            loggedon = target_loggedon(module, target, portal, port)
            if (login and loggedon) or (not login and not loggedon):
                result["changed"] |= False
                if login:
                    result["devicenodes"] = target_device_node(target)
            elif not check:
                if login:
                    target_login(module, target, portal, port)
                    # give udev some time
                    time.sleep(1)
                    result["devicenodes"] = target_device_node(target)
                else:
                    target_logout(module, target)
                result["changed"] |= True
                result["connection_changed"] = True
            else:
                result["changed"] |= True
                result["connection_changed"] = True

    if automatic is not None and not login_to_all_nodes:
        isauto = target_isauto(module, target)
        if (automatic and isauto) or (not automatic and not isauto):
            result["changed"] |= False
            result["automatic_changed"] = False
        elif not check:
            if automatic:
                target_setauto(module, target)
            else:
                target_setmanual(module, target)
            result["changed"] |= True
            result["automatic_changed"] = True
        else:
            result["changed"] |= True
            result["automatic_changed"] = True

    if automatic_portal is not None and not login_to_all_nodes:
        isauto = target_isauto(module, target, portal, port)
        if (automatic_portal and isauto) or (not automatic_portal and not isauto):
            result["changed"] |= False
            result["automatic_portal_changed"] = False
        elif not check:
            if automatic_portal:
                target_setauto(module, target, portal, port)
            else:
                target_setmanual(module, target, portal, port)
            result["changed"] |= True
            result["automatic_portal_changed"] = True
        else:
            result["changed"] |= True
            result["automatic_portal_changed"] = True

    if rescan is not False:
        result["changed"] = True
        result["sessions"] = iscsi_rescan(module, target)

    module.exit_json(**result)


if __name__ == "__main__":
    main()