from functools import partial
from typing import Any, Dict, Optional

from django.http import HttpRequest, HttpResponse

from zerver.decorator import webhook_view
from zerver.lib.exceptions import UnsupportedWebhookEventType
from zerver.lib.request import REQ, has_request_variables
from zerver.lib.response import json_success
from zerver.lib.webhooks.common import check_send_webhook_message
from zerver.models import UserProfile

EPIC_NAME_TEMPLATE = "**{name}**"
STORY_NAME_TEMPLATE = "[{name}]({app_url})"
COMMENT_ADDED_TEMPLATE = "New comment added to the {entity} {name_template}:\n``` quote\n{text}\n```"
NEW_DESC_ADDED_TEMPLATE = "New description added to the {entity} {name_template}:\n``` quote\n{new}\n```"
DESC_CHANGED_TEMPLATE = ("Description for the {entity} {name_template} was changed from:\n"
                         "``` quote\n{old}\n```\nto\n``` quote\n{new}\n```")
DESC_REMOVED_TEMPLATE = "Description for the {entity} {name_template} was removed."
STATE_CHANGED_TEMPLATE = "State of the {entity} {name_template} was changed from **{old}** to **{new}**."
NAME_CHANGED_TEMPLATE = ("The name of the {entity} {name_template} was changed from:\n"
                         "``` quote\n{old}\n```\nto\n``` quote\n{new}\n```")
ARCHIVED_TEMPLATE = "The {entity} {name_template} was {action}."
STORY_TASK_TEMPLATE = "Task **{task_description}** was {action} the story {name_template}."
STORY_TASK_COMPLETED_TEMPLATE = "Task **{task_description}** ({name_template}) was completed. :tada:"
STORY_ADDED_REMOVED_EPIC_TEMPLATE = ("The story {story_name_template} was {action} the"
                                     " epic {epic_name_template}.")
STORY_EPIC_CHANGED_TEMPLATE = ("The story {story_name_template} was moved from {old_epic_name_template}"
                               " to {new_epic_name_template}.")
STORY_ESTIMATE_TEMPLATE = "The estimate for the story {story_name_template} was set to {estimate}."
FILE_ATTACHMENT_TEMPLATE = "A {type} attachment `{file_name}` was added to the story {name_template}."
STORY_LABEL_TEMPLATE = "The label **{label_name}** was added to the story {name_template}."
STORY_UPDATE_PROJECT_TEMPLATE = ("The story {name_template} was moved from"
                                 " the **{old}** project to **{new}**.")
STORY_UPDATE_TYPE_TEMPLATE = ("The type of the story {name_template} was changed"
                              " from **{old_type}** to **{new_type}**.")
DELETE_TEMPLATE = "The {entity_type} **{name}** was deleted."
STORY_UPDATE_OWNER_TEMPLATE = "New owner added to the story {name_template}."
STORY_GITHUB_PR_TEMPLATE = ("New GitHub PR [#{name}]({url}) opened for story"
                            " {name_template} ({old} -> {new}).")
STORY_GITHUB_BRANCH_TEMPLATE = ("New GitHub branch [{name}]({url})"
                                " associated with story {name_template} ({old} -> {new}).")


def get_action_with_primary_id(payload: Dict[str, Any]) -> Dict[str, Any]:
    for action in payload["actions"]:
        if payload["primary_id"] == action["id"]:
            action_with_primary_id = action

    return action_with_primary_id

def get_event(payload: Dict[str, Any]) -> Optional[str]:
    action = get_action_with_primary_id(payload)
    event = "{}_{}".format(action["entity_type"], action["action"])

    if event in IGNORED_EVENTS:
        return None

    changes = action.get("changes")
    if changes is not None:
        if changes.get("description") is not None:
            event = "{}_{}".format(event, "description")
        elif changes.get("state") is not None:
            event = "{}_{}".format(event, "state")
        elif changes.get("workflow_state_id") is not None:
            event = "{}_{}".format(event, "state")
        elif changes.get("name") is not None:
            event = "{}_{}".format(event, "name")
        elif changes.get("archived") is not None:
            event = "{}_{}".format(event, "archived")
        elif changes.get("complete") is not None:
            event = "{}_{}".format(event, "complete")
        elif changes.get("epic_id") is not None:
            event = "{}_{}".format(event, "epic")
        elif changes.get("estimate") is not None:
            event = "{}_{}".format(event, "estimate")
        elif changes.get("file_ids") is not None:
            event = "{}_{}".format(event, "attachment")
        elif changes.get("label_ids") is not None:
            event = "{}_{}".format(event, "label")
        elif changes.get("project_id") is not None:
            event = "{}_{}".format(event, "project")
        elif changes.get("story_type") is not None:
            event = "{}_{}".format(event, "type")
        elif changes.get("owner_ids") is not None:
            event = "{}_{}".format(event, "owner")

    return event

def get_topic_function_based_on_type(payload: Dict[str, Any]) -> Any:
    entity_type = get_action_with_primary_id(payload)["entity_type"]
    return EVENT_TOPIC_FUNCTION_MAPPER.get(entity_type)

def get_delete_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    return DELETE_TEMPLATE.format(**action)

def get_story_create_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)

    if action.get("epic_id") is None:
        message = "New story [{name}]({app_url}) of type **{story_type}** was created."
        kwargs = action
    else:
        message = "New story [{name}]({app_url}) was created and added to the epic **{epic_name}**."
        kwargs = {
            "name": action["name"],
            "app_url": action["app_url"],
        }
        epic_id = action["epic_id"]
        refs = payload["references"]
        for ref in refs:
            if ref["id"] == epic_id:
                kwargs["epic_name"] = ref["name"]

    return message.format(**kwargs)

def get_epic_create_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    message = "New epic **{name}**({state}) was created."
    return message.format(**action)

def get_comment_added_body(payload: Dict[str, Any], entity: str) -> str:
    actions = payload["actions"]
    kwargs = {"entity": entity}
    for action in actions:
        if action["id"] == payload["primary_id"]:
            kwargs["text"] = action["text"]
        elif action["entity_type"] == entity:
            name_template = get_name_template(entity).format(
                name=action["name"],
                app_url=action.get("app_url"),
            )
            kwargs["name_template"] = name_template

    return COMMENT_ADDED_TEMPLATE.format(**kwargs)

def get_update_description_body(payload: Dict[str, Any], entity: str) -> str:
    action = get_action_with_primary_id(payload)
    desc = action["changes"]["description"]

    kwargs = {
        "entity": entity,
        "new": desc["new"],
        "old": desc["old"],
        "name_template": get_name_template(entity).format(
            name=action["name"],
            app_url=action.get("app_url"),
        ),
    }

    if kwargs["new"] and kwargs["old"]:
        body = DESC_CHANGED_TEMPLATE.format(**kwargs)
    elif kwargs["new"]:
        body = NEW_DESC_ADDED_TEMPLATE.format(**kwargs)
    else:
        body = DESC_REMOVED_TEMPLATE.format(**kwargs)

    return body

def get_epic_update_state_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    state = action["changes"]["state"]
    kwargs = {
        "entity": "epic",
        "new": state["new"],
        "old": state["old"],
        "name_template": EPIC_NAME_TEMPLATE.format(name=action["name"]),
    }

    return STATE_CHANGED_TEMPLATE.format(**kwargs)

def get_story_update_state_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    workflow_state_id = action["changes"]["workflow_state_id"]
    references = payload["references"]

    state = {}
    for ref in references:
        if ref["id"] == workflow_state_id["new"]:
            state["new"] = ref["name"]
        if ref["id"] == workflow_state_id["old"]:
            state["old"] = ref["name"]

    kwargs = {
        "entity": "story",
        "new": state["new"],
        "old": state["old"],
        "name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action.get("app_url"),
        ),
    }

    return STATE_CHANGED_TEMPLATE.format(**kwargs)

def get_update_name_body(payload: Dict[str, Any], entity: str) -> str:
    action = get_action_with_primary_id(payload)
    name = action["changes"]["name"]
    kwargs = {
        "entity": entity,
        "new": name["new"],
        "old": name["old"],
        "name_template": get_name_template(entity).format(
            name=action["name"],
            app_url=action.get("app_url"),
        ),
    }

    return NAME_CHANGED_TEMPLATE.format(**kwargs)

def get_update_archived_body(payload: Dict[str, Any], entity: str) -> str:
    primary_action = get_action_with_primary_id(payload)
    archived = primary_action["changes"]["archived"]
    if archived["new"]:
        action = "archived"
    else:
        action = "unarchived"

    kwargs = {
        "entity": entity,
        "name_template": get_name_template(entity).format(
            name=primary_action["name"],
            app_url=primary_action.get("app_url"),
        ),
        "action": action,
    }

    return ARCHIVED_TEMPLATE.format(**kwargs)

def get_story_task_body(payload: Dict[str, Any], action: str) -> str:
    primary_action = get_action_with_primary_id(payload)

    kwargs = {
        "task_description": primary_action["description"],
        "action": action,
    }

    for a in payload["actions"]:
        if a["entity_type"] == "story":
            kwargs["name_template"] = STORY_NAME_TEMPLATE.format(
                name=a["name"],
                app_url=a["app_url"],
            )

    return STORY_TASK_TEMPLATE.format(**kwargs)

def get_story_task_completed_body(payload: Dict[str, Any]) -> Optional[str]:
    action = get_action_with_primary_id(payload)

    kwargs = {
        "task_description": action["description"],
    }

    story_id = action["story_id"]
    for ref in payload["references"]:
        if ref["id"] == story_id:
            kwargs["name_template"] = STORY_NAME_TEMPLATE.format(
                name=ref["name"],
                app_url=ref["app_url"],
            )

    if action["changes"]["complete"]["new"]:
        return STORY_TASK_COMPLETED_TEMPLATE.format(**kwargs)
    else:
        return None

def get_story_update_epic_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)

    kwargs = {
        "story_name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
    }

    new_id = action["changes"]["epic_id"].get("new")
    old_id = action["changes"]["epic_id"].get("old")

    for ref in payload["references"]:
        if ref["id"] == new_id:
            kwargs["new_epic_name_template"] = EPIC_NAME_TEMPLATE.format(
                name=ref["name"])

        if ref["id"] == old_id:
            kwargs["old_epic_name_template"] = EPIC_NAME_TEMPLATE.format(
                name=ref["name"])

    if new_id and old_id:
        return STORY_EPIC_CHANGED_TEMPLATE.format(**kwargs)
    elif new_id:
        kwargs["epic_name_template"] = kwargs["new_epic_name_template"]
        kwargs["action"] = "added to"
    else:
        kwargs["epic_name_template"] = kwargs["old_epic_name_template"]
        kwargs["action"] = "removed from"

    return STORY_ADDED_REMOVED_EPIC_TEMPLATE.format(**kwargs)

def get_story_update_estimate_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)

    kwargs = {
        "story_name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
    }

    new = action["changes"]["estimate"].get("new")
    if new:
        kwargs["estimate"] = f"{new} points"
    else:
        kwargs["estimate"] = "*Unestimated*"

    return STORY_ESTIMATE_TEMPLATE.format(**kwargs)

def get_reference_by_id(payload: Dict[str, Any], ref_id: int) -> Dict[str, Any]:
    ref: Dict[str, Any] = {}
    for reference in payload['references']:
        if reference['id'] == ref_id:
            ref = reference

    return ref

def get_story_create_github_entity_body(payload: Dict[str, Any],
                                        entity: str) -> str:
    action = get_action_with_primary_id(payload)

    story: Dict[str, Any] = {}
    for a in payload['actions']:
        if (a['entity_type'] == 'story' and
                a['changes'].get('workflow_state_id') is not None):
            story = a

    new_state_id = story['changes']['workflow_state_id']['new']
    old_state_id = story['changes']['workflow_state_id']['old']
    new_state = get_reference_by_id(payload, new_state_id)['name']
    old_state = get_reference_by_id(payload, old_state_id)['name']

    kwargs = {
        'name_template': STORY_NAME_TEMPLATE.format(**story),
        'name': action.get('number') if entity == 'pull-request' else action.get('name'),
        'url': action['url'],
        'new': new_state,
        'old': old_state,
    }

    template = STORY_GITHUB_PR_TEMPLATE if entity == 'pull-request' else STORY_GITHUB_BRANCH_TEMPLATE
    return template.format(**kwargs)

def get_story_update_attachment_body(payload: Dict[str, Any]) -> Optional[str]:
    action = get_action_with_primary_id(payload)

    kwargs = {
        "name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
    }
    file_ids_added = action["changes"]["file_ids"].get("adds")

    # If this is a payload for when an attachment is removed, ignore it
    if not file_ids_added:
        return None

    file_id = file_ids_added[0]
    for ref in payload["references"]:
        if ref["id"] == file_id:
            kwargs.update(
                type=ref["entity_type"],
                file_name=ref["name"],
            )

    return FILE_ATTACHMENT_TEMPLATE.format(**kwargs)

def get_story_label_body(payload: Dict[str, Any]) -> Optional[str]:
    action = get_action_with_primary_id(payload)

    kwargs = {
        "name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
    }
    label_ids_added = action["changes"]["label_ids"].get("adds")

    # If this is a payload for when a label is removed, ignore it
    if not label_ids_added:
        return None

    label_id = label_ids_added[0]

    label_name = ''
    for action in payload["actions"]:
        if action['id'] == label_id:
            label_name = action.get('name', '')

    if not label_name:
        for reference in payload["references"]:
            if reference["id"] == label_id:
                label_name = reference.get('name', '')

    kwargs.update(label_name=label_name)

    return STORY_LABEL_TEMPLATE.format(**kwargs)

def get_story_update_project_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    kwargs = {
        "name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
    }

    new_project_id = action["changes"]["project_id"]["new"]
    old_project_id = action["changes"]["project_id"]["old"]
    for ref in payload["references"]:
        if ref["id"] == new_project_id:
            kwargs.update(new=ref["name"])
        if ref["id"] == old_project_id:
            kwargs.update(old=ref["name"])

    return STORY_UPDATE_PROJECT_TEMPLATE.format(**kwargs)

def get_story_update_type_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    kwargs = {
        "name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
        "new_type": action["changes"]["story_type"]["new"],
        "old_type": action["changes"]["story_type"]["old"],
    }

    return STORY_UPDATE_TYPE_TEMPLATE.format(**kwargs)

def get_story_update_owner_body(payload: Dict[str, Any]) -> str:
    action = get_action_with_primary_id(payload)
    kwargs = {
        "name_template": STORY_NAME_TEMPLATE.format(
            name=action["name"],
            app_url=action["app_url"],
        ),
    }

    return STORY_UPDATE_OWNER_TEMPLATE.format(**kwargs)

def get_entity_name(payload: Dict[str, Any], entity: Optional[str]=None) -> Optional[str]:
    action = get_action_with_primary_id(payload)
    name = action.get("name")

    if name is None or action['entity_type'] == 'branch':
        for action in payload["actions"]:
            if action["entity_type"] == entity:
                name = action["name"]

    if name is None:
        for ref in payload["references"]:
            if ref["entity_type"] == entity:
                name = ref["name"]

    return name

def get_name_template(entity: str) -> str:
    if entity == "story":
        return STORY_NAME_TEMPLATE
    return EPIC_NAME_TEMPLATE

EVENT_BODY_FUNCTION_MAPPER = {
    "story_update_archived": partial(get_update_archived_body, entity='story'),
    "epic_update_archived": partial(get_update_archived_body, entity='epic'),
    "story_create": get_story_create_body,
    "pull-request_create": partial(get_story_create_github_entity_body, entity='pull-request'),
    "branch_create": partial(get_story_create_github_entity_body, entity='branch'),
    "story_delete": get_delete_body,
    "epic_delete": get_delete_body,
    "story-task_create": partial(get_story_task_body, action="added to"),
    "story-task_delete": partial(get_story_task_body, action="removed from"),
    "story-task_update_complete": get_story_task_completed_body,
    "story_update_epic": get_story_update_epic_body,
    "story_update_estimate": get_story_update_estimate_body,
    "story_update_attachment": get_story_update_attachment_body,
    "story_update_label": get_story_label_body,
    "story_update_owner": get_story_update_owner_body,
    "story_update_project": get_story_update_project_body,
    "story_update_type": get_story_update_type_body,
    "epic_create": get_epic_create_body,
    "epic-comment_create": partial(get_comment_added_body, entity='epic'),
    "story-comment_create": partial(get_comment_added_body, entity='story'),
    "epic_update_description": partial(get_update_description_body, entity='epic'),
    "story_update_description": partial(get_update_description_body, entity='story'),
    "epic_update_state": get_epic_update_state_body,
    "story_update_state": get_story_update_state_body,
    "epic_update_name": partial(get_update_name_body, entity='epic'),
    "story_update_name": partial(get_update_name_body, entity='story'),
}

EVENT_TOPIC_FUNCTION_MAPPER = {
    "story": partial(get_entity_name, entity='story'),
    "pull-request": partial(get_entity_name, entity='story'),
    "branch": partial(get_entity_name, entity='story'),
    "story-comment": partial(get_entity_name, entity='story'),
    "story-task": partial(get_entity_name, entity='story'),
    "epic": partial(get_entity_name, entity='epic'),
    "epic-comment": partial(get_entity_name, entity='epic'),
}

IGNORED_EVENTS = {
    'story-comment_update',
}

@webhook_view('ClubHouse')
@has_request_variables
def api_clubhouse_webhook(
        request: HttpRequest, user_profile: UserProfile,
        payload: Optional[Dict[str, Any]]=REQ(argument_type='body'),
) -> HttpResponse:

    # Clubhouse has a tendency to send empty POST requests to
    # third-party endpoints. It is unclear as to which event type
    # such requests correspond to. So, it is best to ignore such
    # requests for now.
    if payload is None:
        return json_success()

    event = get_event(payload)
    if event is None:
        return json_success()

    body_func: Any = EVENT_BODY_FUNCTION_MAPPER.get(event)
    topic_func = get_topic_function_based_on_type(payload)
    if body_func is None or topic_func is None:
        raise UnsupportedWebhookEventType(event)
    topic = topic_func(payload)
    body = body_func(payload)

    if topic and body:
        check_send_webhook_message(request, user_profile, topic, body)

    return json_success()