"""Pydantic request/response schemas (API contract)."""
from __future__ import annotations

import uuid
from datetime import datetime
from typing import Any, Literal

from pydantic import (
    BaseModel,
    ConfigDict,
    Field,
    SerializerFunctionWrapHandler,
    field_validator,
    model_serializer,
)


class HealthResponse(BaseModel):
    status: str
    db: str
    version: str
    environment: str


class SuggestionList(BaseModel):
    suggestions: list[str]


class ChatRequest(BaseModel):
    message: str = Field(min_length=1, max_length=4000)


class LoginRequest(BaseModel):
    """``POST /api/login`` body (phase 16): the single admin's password.

    An empty or wrong password is a 401 with one generic detail — never a
    422 that would hint at input-shape differences.
    """

    password: str = ""


class WhoamiResponse(BaseModel):
    """``GET /api/whoami`` (phase 16) — drives all UI gating."""

    authenticated: bool
    role: str  # "admin" | "anonymous"


class SourceRef(BaseModel):
    source: str
    path: str
    title: str


class ChatThinkingEvent(BaseModel):
    """SSE thinking event: one chunk of the model's reasoning (phase 17).

    PLAN §4 extension (A15, owner permission 2026-08-23): frames of the
    shape ``{type: "thinking", text: str}`` stream ahead of the
    ``delta`` frames in practice (the model reasons before it answers). The
    client renders them in a collapsible "Thinking" block; the ``done``
    event shape is unchanged and thinking text never travels on it.
    Sibling of :class:`ChatErrorEvent`.
    """

    type: str = "thinking"
    text: str


class ChatToolEvent(BaseModel):
    """SSE frame for one agent tool call (phase 37, PLAN §4 extension).

    A15 extension (owner permission 2026-08-26): a grounded turn may call
    the server-side document tools (``list_documents`` / ``read_document``,
    see :mod:`app.rag.agent`); each model-requested call streams as
    ``{type: "tool", name: str, argument: str | null}`` ahead of the
    answer's ``delta`` frames. ``argument`` is the read document's
    ``"source/path"`` for ``read_document`` and null otherwise. The client
    renders each frame as a "calling tool" line/state (phase 37 task 05);
    the ``delta`` / ``done`` shapes are unchanged — the read document is
    reflected in ``done.sources`` instead.
    """

    type: Literal["tool"] = "tool"
    name: str  # "list_documents" | "read_document"
    argument: str | None = None  # "source/path" for read_document


class ChatDoneEvent(BaseModel):
    """Final SSE event of a chat turn: metadata for the finished answer."""

    type: str = "done"
    deflected: bool
    sources: list[SourceRef]
    suggestions: list[str] = []


class ChatErrorEvent(BaseModel):
    """SSE error event: a turn that cannot complete (PLAN §4).

    The client's loading-feedback state machine (phase 06) keys off this
    exact shape — ``{type: "error", detail: str}`` — to flip to the error
    state and re-enable the send button.
    """

    type: str = "error"
    detail: str


class DocSummary(BaseModel):
    """One indexed document as shown on the Sources page / API."""

    id: str
    source: str
    path: str
    title: str
    chunks: int
    indexed_at: str


class DocList(BaseModel):
    """Response of ``GET /api/docs`` (empty list → designed empty state)."""

    documents: list[DocSummary]


class DocContent(BaseModel):
    """One indexed document's full content (feeds the viewer page, phase 10)."""

    source: str
    path: str
    title: str
    format: str
    #: Lite-model summary (phase 30) — non-markdown A9 docs only; None for
    #: markdown documents, pre-phase-30 rows, and the fail-soft path where
    #: summary generation failed but the document was still indexed.
    summary: str | None = None
    content: str
    indexed_at: str
    chunks: int


class SteeringNoteIn(BaseModel):
    """``POST /api/steering`` body: one tuning instruction (phase 15).

    The note is trimmed *before* the length constraints run, so a
    whitespace-only body is a 422 and a 2000-char note with surrounding
    spaces still passes.
    """

    note: str = Field(min_length=1, max_length=2000)

    @field_validator("note", mode="before")
    @classmethod
    def _trim_note(cls, v: object) -> object:
        return v.strip() if isinstance(v, str) else v


class SteeringNoteUpdate(BaseModel):
    """``PUT /api/steering/{id}`` body: a new tuning instruction (phase 27).

    Mirrors :class:`SteeringNoteIn` — the note is trimmed *before* the
    length constraints run, so an empty/whitespace body is a 422 and a
    full replacement that is ≤2000 chars after the trim still passes.
    """

    note: str = Field(min_length=1, max_length=2000)

    @field_validator("note", mode="before")
    @classmethod
    def _trim_note(cls, v: object) -> object:
        return v.strip() if isinstance(v, str) else v


class SteeringNote(BaseModel):
    """One stored steering note (API shape — ISO-8601 ``created_at``)."""

    id: uuid.UUID
    note: str
    created_at: datetime


class SteeringNoteList(BaseModel):
    """``GET /api/steering`` response: all notes, newest first."""

    notes: list[SteeringNote]


class GitSourceIn(BaseModel):
    """``POST /api/git-sources`` body (phase 35, task 02; ``kind``, phase 38).

    ``kind`` selects the source kind and which field carries its location:

    * ``"git"`` (default) — ``url`` is the repo URL. Mirrors the
      phase-35 contract: trimmed *before* the length constraints run, so a
      whitespace-only body is a 422 and a URL with surrounding spaces is
      stored clean. Shape validation (``https://``, ``ssh://``, ``git@``)
      and the kind-field rules (url present, no path) happen in the API
      layer so the 422/409 details stay fixed strings that never echo the
      input (credential safety).
    * ``"local"`` — ``path`` is an existing directory on the server.
      Trimmed here; the API layer then ``expanduser()``s it and requires an
      absolute existing directory (else 422 naming the path — the path is
      not a secret, unlike a git URL) and no ``url``.
    """

    kind: Literal["git", "local"] = "git"
    url: str | None = Field(default=None, min_length=1, max_length=500)
    path: str | None = Field(default=None, min_length=1, max_length=2000)

    @field_validator("url", mode="before")
    @classmethod
    def _trim_url(cls, v: object) -> object:
        return v.strip() if isinstance(v, str) else v

    @field_validator("path", mode="before")
    @classmethod
    def _trim_path(cls, v: object) -> object:
        return v.strip() if isinstance(v, str) else v


class GitSourceOut(BaseModel):
    """One created git source as returned by ``POST`` (phase 35, task 02).

    ``id`` / ``added_at`` are non-null for a stored row. ``url`` is the
    row's location column: the repo URL for ``kind=git`` rows and, for
    ``kind=local`` rows, the stored (expanded) directory path — the
    phase-35 response shape is unchanged by phase 38, so a local 201
    reports its path in ``url`` and the full row (``kind`` + ``path``)
    via ``GET``.
    """

    id: uuid.UUID | None
    url: str
    added_at: datetime | None


class GitSourceRow(BaseModel):
    """One row of ``GET /api/git-sources`` (phase 35; ``kind``/``path``,
    phase 38, task 02).

    ``kind`` discriminates the row: git rows (and the git-only
    ``BOR_GIT_SOURCES`` env-fallback rows) carry ``url`` and
    ``path: null``; local rows carry ``path`` (the absolute directory,
    expanded) and the same string in ``url`` (the table's NOT-NULL
    location column). ``id`` / ``added_at`` are nullable: env-fallback
    rows (table empty) carry neither.
    """

    id: uuid.UUID | None
    kind: Literal["git", "local"]
    url: str
    path: str | None
    added_at: datetime | None


class GitSourceList(BaseModel):
    """``GET /api/git-sources`` response (phase 35, task 02).

    ``from_env`` is True only when the ``git_sources`` table is empty and
    the list comes from ``BOR_GIT_SOURCES`` (the phase's locked fallback
    — env rows are git-only and report ``kind: "git"``, ``path: null``);
    once the table has rows the env var is ignored and ``from_env`` is
    False — the UI is the source of truth.
    """

    sources: list[GitSourceRow]
    from_env: bool


class UploadOut(BaseModel):
    """``POST /api/git-sources/upload`` response (phase 49, task 02).

    The uploaded source's name (filename minus the archive suffix) plus
    the SAME count keys as the admin sync's success ``detail``
    (``files``, ``added``, ``updated``, ``unchanged``, ``pruned``,
    ``errors``, ``chunks`` — ``app.api.sync._run_sync``) and the
    ``overview`` flag: the Sources page renders the same
    "N added · N pruned" result line for both.
    """

    source: str
    files: int
    added: int
    updated: int
    unchanged: int
    pruned: int
    errors: int
    chunks: int
    overview: bool


class ToolCall(BaseModel):
    """One agent tool-call record (the phase-37 ``tools`` record shape).

    Mirrors the ``{name, argument}`` pair the SSE ``tool`` frames carry
    (PLAN §4 extension): ``argument`` is the read document's
    ``"source/path"`` for ``read_document`` and null otherwise. Stored
    inside :class:`ChatMessage.tools` so a saved chat restores the
    "calling tool" lines pixel-identical (phase 50).
    """

    name: str
    argument: str | None = None


class ChatMessage(BaseModel):
    """One conversation record in the ``bor.chat.v1`` localStorage shape
    (phase 14) — the stored ``messages`` payload of a saved chat (phase 50).

    ``{who, text, sources?, deflected?, suggestions?, thinking?, tools?,
    stopped?}`` — raw text, never HTML, so a saved chat restores
    pixel-identical through the existing ``renderStoredMessage`` path.
    ``extra="forbid"`` rejects unknown keys (a corrupted or HTML-shaped
    payload, e.g. a stray ``<b>``-ish extra key) at the boundary with a
    422, so nothing outside this shape can poison a restored
    conversation.
    """

    model_config = ConfigDict(extra="forbid")

    who: Literal["user", "brain"]
    text: str = Field(min_length=1)
    sources: list[SourceRef] | None = None
    deflected: bool | None = None
    suggestions: list[str] | None = None
    thinking: str | None = None
    tools: list[ToolCall] | None = None
    stopped: bool | None = None


class SavedChatCreate(BaseModel):
    """``POST /api/chats`` body (phase 50, task 02; ``share``, phase 51
    task 02).

    ``title`` is optional: when absent or blank the API auto-titles the
    row (the first user message's text, whitespace-collapsed, truncated
    to 120 chars — the owner-locked convention). ``messages`` must be
    non-empty — a saved chat with nothing to restore is meaningless.

    ``share`` (phase 51, owner-locked 2026-08-29): when true, the row is
    shared in the SAME commit — ``share_token = uuid.uuid4()`` is set on
    the fresh row before the INSERT, so one request saves AND shares
    (the chat page's Share button on an unsaved conversation, the
    save-then-share contract). The response then carries ``share_url``
    (see :class:`SavedChatOut`). Default false — a plain Save is
    unchanged by phase 51.
    """

    title: str | None = Field(default=None, max_length=500)
    messages: list[ChatMessage] = Field(min_length=1)
    share: bool = False


class SavedChatUpdate(BaseModel):
    """``PUT /api/chats/{chat_id}`` body (phase 50, task 02).

    ``messages`` is a full replacement (the re-Save upsert semantics —
    re-Saving the same conversation updates the same row, never a new
    one). ``title`` is replaced only when supplied — an absent (or
    blank) ``title`` keeps the row's current title.
    """

    title: str | None = Field(default=None, max_length=500)
    messages: list[ChatMessage] = Field(min_length=1)


def _drop_absent_share_url(model: BaseModel, handler: SerializerFunctionWrapHandler) -> Any:
    """The ``share_url`` omission rule (phase 51, task 02): ``None`` →
    ABSENT from the JSON (not ``"share_url": null``) — an unshared chat
    exposes no share surface at all, and the History column renders the
    unshared state from the key's absence.

    A ``mode="wrap"`` model serializer: the default (recursive) dump runs
    first, then only the TOP-LEVEL key is dropped when null. The
    recursion matters — a route-level ``response_model_exclude_none``
    would also drop the nested ``ChatMessage`` nulls (``sources: null``
    and friends), which the byte-identical round-trip contract (phase
    50) forbids.
    """
    data = handler(model)
    if data.get("share_url") is None:
        data.pop("share_url", None)
    return data


class SavedChatOut(BaseModel):
    """One saved chat, full payload (create/get/put response, phase 50;
    ``share_url``, phase 51 task 02).

    ``messages`` round-trips the ``bor.chat.v1`` record list losslessly
    — the restore path is pixel-identical by construction.

    ``share_url`` (phase 51): ``"/shared/<token>"`` while the chat is
    shared, ABSENT from the JSON when unshared (``None`` → dropped by
    :func:`_drop_absent_share_url` — no ``null`` in the wire shape).
    """

    id: uuid.UUID
    title: str
    created_at: datetime
    updated_at: datetime
    message_count: int
    messages: list[ChatMessage]
    share_url: str | None = None

    @model_serializer(mode="wrap")
    def _serialize(self, handler: SerializerFunctionWrapHandler) -> Any:
        return _drop_absent_share_url(self, handler)


class SavedChatRow(BaseModel):
    """One row of ``GET /api/chats`` (the History page's list shape,
    phase 50; ``share_url``, phase 51 task 02).

    No payloads in the list — the row carries only what the table needs
    (Title, Messages count, Updated). ``share_url`` is populated here so
    the History page's Share column renders straight from ``GET
    /api/chats`` — no second fetch per row (``None`` → absent, the same
    omission rule as :class:`SavedChatOut`).
    """

    id: uuid.UUID
    title: str
    updated_at: datetime
    message_count: int
    share_url: str | None = None

    @model_serializer(mode="wrap")
    def _serialize(self, handler: SerializerFunctionWrapHandler) -> Any:
        return _drop_absent_share_url(self, handler)


class SavedChatList(BaseModel):
    """``GET /api/chats`` response: saved chats, latest activity first
    (``updated_at desc, id desc``)."""

    chats: list[SavedChatRow]


class SharedChatOut(BaseModel):
    """``GET /api/shared/{token}`` body (phase 51, task 01) — the PUBLIC
    read shape of a shared chat.

    Deliberately minimal: ``title`` + ``messages`` only. No id, no
    timestamps, no token, no ``message_count`` — a shared chat is a
    content snapshot, not a handle: nothing in the body can be turned
    back into an admin-surface request, and the token itself never
    round-trips (it is the URL, not data).
    """

    title: str
    messages: list[ChatMessage]


class ShareOut(BaseModel):
    """``POST /api/chats/{chat_id}/share`` response (phase 51, task 01).

    ``share_url`` is the path (``/shared/<token>``) the UI copies into
    the clipboard — the owner's own origin supplies the scheme/host.
    Idempotent: a re-share returns the existing, unchanged token.
    """

    chat_id: uuid.UUID
    share_url: str


class UnshareOut(BaseModel):
    """``POST /api/chats/{chat_id}/unshare`` response (phase 51, task 01).

    ``shared: false`` is reported unconditionally — the endpoint is
    idempotent, so an already-unshared chat unshares cleanly (200).
    """

    chat_id: uuid.UUID
    shared: bool