"""Request and response shapes for the documents API.

Kept in one module because the whole package answers with the same handful of
document shapes: a summary in lists, a detail on a single document, and the
few command bodies that change one.
"""

import uuid
from datetime import datetime
from enum import StrEnum

from pydantic import BaseModel, ConfigDict, Field

from app.models import (
    AccessReason,
    DocumentEventAction,
    DocumentStatus,
    DocumentVisibility,
)


class DocumentSummary(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: uuid.UUID
    title: str
    status: DocumentStatus
    visibility: DocumentVisibility
    department_id: uuid.UUID | None
    created_at: datetime
    updated_at: datetime
    # Why this user sees it and what they may do — so the UI can explain
    # access instead of leaving the rules implicit.
    access_reason: AccessReason
    can_edit: bool
    # Unanswered questions about this document. A published document with an
    # open question is readable but not settled, and every surface that shows
    # the document says so — including the sources under a chat answer.
    open_reviews: int
    # Shipped with the product: read-only, and never deletable.
    is_builtin: bool


class DepartmentRef(BaseModel):
    id: uuid.UUID
    name: str


class ReviewOut(BaseModel):
    """One request to check this document. Open while `resolved_at` is null."""

    id: uuid.UUID
    question: str | None
    requester_name: str | None
    reviewer_id: uuid.UUID | None
    reviewer_name: str | None
    created_at: datetime
    resolved_at: datetime | None
    resolved_by_name: str | None
    # Whether the caller is the one being asked, so the UI can offer the
    # answer rather than just showing the question.
    is_mine: bool


class DocumentDetail(DocumentSummary):
    content_md: str
    # Every request on this document, oldest first, open and answered — the
    # answered ones are the record of what was already checked.
    reviews: list[ReviewOut] = []
    # Additional departments the document is shared with, on top of its owning
    # `department_id` (the `doc_permissions` grants). Resolved where the endpoint
    # looks it up (get_document, the departments endpoint).
    shared_departments: list[DepartmentRef] = []


class DocumentSort(StrEnum):
    """How the browse list is ordered. Deliberately two options: "what
    changed" and "what is new" are the two questions people actually ask of
    a document list."""

    updated = "updated"
    created = "created"


class DocumentPage(BaseModel):
    items: list[DocumentSummary]
    # Total matching the filters, not the page — the UI needs it to know
    # whether there is a next page at all.
    total: int
    per_page: int


class DocumentSearchHit(DocumentSummary):
    """A search result: the document plus the section that matched.

    Empty `heading_path` means the match was on the title, not a section.
    """

    heading_path: str = ""


class DocumentStats(BaseModel):
    """Company-wide counts, read by the landing page's first-run guide.

    Aggregates only — no titles, no per-user data. Deliberately not
    permission-filtered: a bare count reveals nothing about content.
    """

    documents_total: int
    departments_total: int


class DocumentCreate(BaseModel):
    """Start a new document the user will write in the editor.

    With a `template_id` the draft opens on that template's Markdown skeleton
    and title; without one it starts blank and `title` is required. The result
    is a `draft` — author-only and never indexed until it is published."""

    template_id: uuid.UUID | None = None
    title: str | None = None
    visibility: DocumentVisibility | None = None
    # When the capture started from a chat: its subject is summarized and kept
    # on the draft as background for section refinement.
    conversation_id: uuid.UUID | None = None


class DocumentUpdate(BaseModel):
    title: str | None = None
    content_md: str | None = None
    visibility: DocumentVisibility | None = None
    # Only the archive transition is settable here; publishing has its own
    # endpoint, because it indexes the document.
    status: DocumentStatus | None = None
    # An admin may knowingly make a change that removes their own access; an
    # author never can (they keep access as author). See access.guard_self_lockout.
    # Nullable (not `bool = False`) so it stays optional in the generated client.
    confirm_lockout: bool | None = None
    # Continuing an EXISTING document out of a chat: the same background the
    # create path attaches, for the document that already covers the topic.
    conversation_id: uuid.UUID | None = None


class DocumentDepartments(BaseModel):
    """The full set of ADDITIONAL departments the document is shared with (on
    top of the owning department) — replaces the existing grants."""

    department_ids: list[uuid.UUID]
    confirm_lockout: bool | None = None


class ReviewerCandidate(BaseModel):
    """A user the author may ask to check a document — id + name only."""

    id: uuid.UUID
    name: str


class ReviewRequestBody(BaseModel):
    """Ask someone to check this document, optionally about something specific
    ("do the holiday numbers still hold?")."""

    reviewer_id: uuid.UUID
    question: str | None = Field(default=None, max_length=2000)


class DocumentEventOut(BaseModel):
    """One entry in a document's history timeline — metadata only."""

    id: uuid.UUID
    action: DocumentEventAction
    actor_id: uuid.UUID | None
    # Null once the actor's account is deleted (SET NULL on the event).
    actor_name: str | None
    visibility: DocumentVisibility | None
    created_at: datetime
    # A content snapshot exists for this event and can be fetched for diffing.
    has_snapshot: bool


class DocumentVersion(BaseModel):
    """A past version's frozen content, for viewing or diffing.

    A snapshot is taken *after* its event, so `content_md` is the state this
    event produced and `previous_content_md` the state it started from — the
    pair is what "what did this change do?" needs. `previous_content_md` is
    null for the first snapshot, where everything was added.
    """

    id: uuid.UUID
    action: DocumentEventAction
    actor_id: uuid.UUID | None
    actor_name: str | None
    created_at: datetime
    title: str | None
    content_md: str | None
    previous_content_md: str | None
    visibility: DocumentVisibility | None