from datetime import datetime
from typing import Literal, Optional, Union

from pydantic import BaseModel, Field
from pydantic.types import NonNegativeInt


class TwitterEngagements(BaseModel):
    """Engagement counts from Twitter"""

    retweet: NonNegativeInt
    like: NonNegativeInt
    comment: NonNegativeInt
    share: NonNegativeInt


class RedditEngagements(BaseModel):
    """Engagement counts from Reddit"""

    upvote: NonNegativeInt
    downvote: NonNegativeInt
    comment: NonNegativeInt
    award: NonNegativeInt


class FacebookEngagements(BaseModel):
    """Engagement counts from Facebook"""

    like: NonNegativeInt
    love: NonNegativeInt
    care: NonNegativeInt
    haha: NonNegativeInt
    wow: NonNegativeInt
    sad: NonNegativeInt
    angry: NonNegativeInt
    comment: NonNegativeInt
    share: NonNegativeInt


class ContentItem(BaseModel):
    """A content item to be ranked"""

    id: str = Field(
        description="A unique ID describing a specific piece of content. We will do our best to make an ID for a given item persist between requests, but that property is not guaranteed."
    )

    post_id: Optional[str] = Field(
        description="The ID of the post to which this comment belongs. Useful for linking comments to their post when comments are shown in a feed. Currently this UX only exists on Facebook.",
        default=None
    )

    parent_id: Optional[str] = Field(
        description="For threaded comments, this identifies the comment to which this one is a reply. Blank for top-level comments.",
        default=None
    )

    title: Optional[str] = Field(
        description="The post title, only available on reddit posts.",
        default=None
    )

    text: str = Field(
        description="The text of the content item. Assume UTF-8, and that leading and trailing whitespace have been trimmed."
    )

    author_name_hash: str = Field(
        description="A hash of the author's name (salted). Use this to determine which posts are by the same author. When the post is by the current user, this should match `session.user_name_hash`."
    )

    type: Literal["post", "comment"] = Field(
        description="Whether the content item is a `post` or `comment`. On Twitter, tweets will be identified as `comment` when they are replies displayed on the page for a single tweet."
    )

    created_at: datetime = Field(
        description="The time that the item was created in UTC, in `YYYY-MM-DD hh:mm:ss` format, at the highest resolution available (which may be as low as the hour)."
    )

    engagements: Union[TwitterEngagements, RedditEngagements, FacebookEngagements] = Field(description="Engagement counts for the content item.")


class Session(BaseModel):
    """Data that is scoped to the user's browsing session (generally a single page view)"""

    user_id: str = Field(description="A unique id for this study participant. Will remain fixed for the duration of the experiment.")
    user_name_hash: str = Field(
        description="A (salted) hash of the user's username. We'll do our best to make it match the `item.author_name_hash` on posts authored by the current user."
    )
    platform: Literal['twitter', 'reddit', 'facebook'] = Field(description="The platform on which the user is viewing content.")
    current_time: datetime = Field(
        description="The current time according to the user's browser, in UTC, in `YYYY-MM-DD hh:mm:ss` format."
    )


class RankingRequest(BaseModel):
    """A complete ranking request"""

    session: Session
    items: list[ContentItem]