"""Knowledge ingestion endpoints (KNOWLEDGE_SURFACE_PLAN.md §4, N10/N10f).

One click over all of a user's parseable documents:

    POST /api/v1/knowledge/ingest        -> 202 {job_id}
    GET  /api/v1/knowledge/jobs/{job_id} -> job state, per-document results
    GET  /api/v1/knowledge/jobs          -> recent jobs for a user

The work is asynchronous by necessity — parse (~80 s) plus extract (~170 s) for
a nine-page document is far past any HTTP timeout — so the route admits a batch
and returns immediately. Polling rather than SSE (decided 2026-09-07): a job row
survives a refresh and a dropped connection, a stream does not, and a 4-minute
stream would hold a worker for its duration.

`GET /jobs/{job_id}` returns **404** for an unknown id, following
`GET /traceability` rather than the tri-state 200 of `GET /charts`. The
difference is real: charts is called unconditionally on every turn where absence
is normal, whereas a polled `job_id` was handed to the caller, so its absence is
genuinely exceptional.

⚠️ **No caller authentication — decided 2026-09-07, not inherited.** `user_id` is
caller-supplied, exactly like every other live endpoint. The service-secret gate
(DEV_PLAN §0.7 #37) cannot be armed here for the same reason it was unwired
there: the browser SPA is the sole caller, we do not own that repo, and a secret
shipped to a browser is not a secret. Arming it would 401 the feature.

But this is a **write that spends LLM budget**, which is a different risk class
from the read surface, so the posture is not inherited silently — it is bounded
by four controls, and the gap they leave is stated rather than papered over:

  1. **Rate limit** (below) — caps calls per client per window.
  2. **Single-flight per scope** — a second click returns the running job.
  3. **Pre-flight spend ceiling** — the free stages produce an exact estimate and
     the job stops rather than spending past it (N10c, lands with the pipeline).
  4. **Content-addressed idempotency** — re-ingesting an unchanged document
     re-spends nothing (N10c).

**What they do not do is identify the caller.** `user_id` is still whatever the
request says, so one user can spend budget under another's id. That closes only
with a real forwarded identity (DEV_PLAN #43). Recorded here so the next reader
knows this is a bounded, accepted posture and not an oversight.

`scope_id` is deliberately NOT accepted from the caller: it is derived
server-side from `users.company`. Accepting a tenant key on an unauthenticated
route is a cross-tenant write with extra steps.
"""

import uuid
from datetime import datetime
from typing import Literal

from fastapi import APIRouter, HTTPException, Query, Request, status
from pydantic import BaseModel, Field, field_validator

from src.knowledge_domain.service import KnowledgeService
from src.knowledge_extraction.queue.review_queue import build_queue
from src.knowledge_ingest.knowledge_store import KnowledgeStore
from src.knowledge_ingest.models import IngestJob
from src.knowledge_ingest.selector import resolve_scope_id
from src.knowledge_ingest.service import IngestService
from src.middlewares.logging import get_logger, log_execution
from src.middlewares.rate_limit import limiter

# NOTE: this module must NOT use `from __future__ import annotations`.
# With it, FastAPI cannot resolve a Pydantic body model's annotation through
# the @log_execution wrapper and silently demotes it to a query parameter —
# every POST then 422s with `loc: [query, payload]`. No router here carries it.

logger = get_logger("knowledge_api")
router = APIRouter(prefix="/api/v1/knowledge", tags=["Knowledge"])

# Warm, process-shared service — mirrors the chat and charts endpoints'
# module-level instances. Holding one instance is also what makes single-flight
# meaningful: the lock lives here.
_service = IngestService()
_store = KnowledgeStore()
_knowledge = KnowledgeService(_store)


def _require_uuid(value: str, field: str) -> str:
    """422 on a malformed id rather than a confusing downstream miss (F-22)."""
    try:
        uuid.UUID(value)
    except (ValueError, AttributeError, TypeError) as e:
        raise ValueError(f"{field} must be a UUID string") from e
    return value


class IngestRequest(BaseModel):
    user_id: str = Field(..., description="The caller. Scope is derived from it.")
    document_ids: list[str] | None = Field(
        default=None,
        description=(
            "Optional. Omit to ingest every parseable document this user owns — "
            "the one-click case. Named ids are still filtered by owner and type."
        ),
    )
    reparse: bool = Field(
        default=False,
        description=(
            "Re-parse even when the content hash already matches a stored "
            "artifact. Off by default: on, it silently re-spends on every call."
        ),
    )
    review_mode: Literal["expert", "llm"] = Field(
        default="expert",
        description=(
            "Who rules on what this batch produces. 'expert' leaves every "
            "entry waiting for a human. 'llm' approves them on arrival with "
            "NO reviewer step and no second opinion — the entries were "
            "written by a model and are accepted as-is. Choosing it records "
            "`authorised_by` against the caller, so an entry approved this "
            "way can always say who allowed it."
        ),
    )

    @field_validator("user_id")
    @classmethod
    def _user_id_is_uuid(cls, v: str) -> str:
        return _require_uuid(v, "user_id")


class IngestAccepted(BaseModel):
    job_id: str
    status: str
    stage: str | None = None
    n_requested: int
    reused: bool = Field(
        ...,
        description=(
            "True when a job for this scope was already in flight and is being "
            "returned instead of a second one starting."
        ),
    )
    skipped: list[dict] = Field(
        default_factory=list,
        description="Documents the batch declined, each with a reason.",
    )
    message: str


@router.post(
    "/ingest",
    response_model=IngestAccepted,
    status_code=status.HTTP_202_ACCEPTED,
    summary="Extract knowledge from a user's documents (async batch)",
)
# N11, control 1 of 4. Deliberately far below the chat route's 30/minute: this
# starts GPU-less but LLM-spending batch work, and a legitimate caller clicks it
# a few times a year, not a few times a minute. `slowapi` needs a Starlette
# `Request` param named `request`, which is why the body is `payload`.
# NOTE: `get_remote_address` buckets by client IP — if calls ever arrive through
# a proxy, every caller shares one bucket. Revisit when identity is forwarded.
@limiter.limit("5/minute")
@log_execution(logger)
async def ingest(request: Request, payload: IngestRequest) -> IngestAccepted:
    """Admit a batch and return immediately. Poll `GET /jobs/{job_id}`."""
    job, reused = await _service.start(
        user_id=payload.user_id,
        document_ids=payload.document_ids,
        review_mode=payload.review_mode,
    )
    if reused:
        message = "A job for this scope is already running; returning it."
    elif job.n_requested:
        message = f"Ingesting {job.n_requested} document(s)."
    else:
        message = job.error_message or "Nothing to ingest."

    return IngestAccepted(
        job_id=job.id,
        status=job.status,
        stage=job.stage,
        n_requested=job.n_requested,
        reused=reused,
        skipped=[s.model_dump() for s in job.skipped],
        message=message,
    )


@router.get(
    "/jobs/{job_id}",
    response_model=IngestJob,
    summary="Poll one ingestion job",
)
@log_execution(logger)
async def get_job(job_id: str) -> IngestJob:
    """Job state and per-document outcomes. 404 when the id is unknown."""
    job = await _service.get(job_id)
    if job is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"No ingestion job with id {job_id}.",
        )
    return job


@router.get(
    "/jobs",
    response_model=list[IngestJob],
    summary="Recent ingestion jobs for a user",
)
@log_execution(logger)
async def list_jobs(
    user_id: str = Query(..., description="Owner of the jobs"),
    limit: int = Query(20, ge=1, le=100),
) -> list[IngestJob]:
    """Lets a caller recover after a refresh without having stashed a job_id."""
    return await _service.list_for_user(user_id, limit)


# ── Read + review surface (N10b, N12b) ───────────────────────────────────────
#
# Everything below resolves `scope_id` from `user_id` server-side and filters on
# it. The tenant key is never accepted from the caller: taking it from the
# request on an unauthenticated route would be a cross-tenant read with extra
# steps.


class KnowledgeDocumentSummary(BaseModel):
    knowledge_document_id: str
    doc_id: str
    document_id: str | None = None
    n_pages: int
    n_chunks: int
    schema_version: str
    parser: str
    content_hash: str
    created_at: datetime | None = None


class EntrySummary(BaseModel):
    entity_id: str
    kind: str
    label: str | None = None
    mention_count: int
    extraction_status: str | None = None
    diff_status: str | None = None
    definition_conflict: bool
    payload: dict
    review: dict | None = Field(
        default=None,
        description="Current expert decision for this entity, if any.",
    )


class ReviewRequest(BaseModel):
    decision: Literal["approved", "edited", "rejected"]
    reviewer_id: str
    edited_payload: dict | None = Field(
        default=None,
        description="Required for `edited` — the expert's corrected entry.",
    )
    note: str | None = None


class ReviewAccepted(BaseModel):
    review_id: str
    entity_id: str
    decision: str
    content_hash: str
    message: str


@router.get(
    "/documents",
    response_model=list[KnowledgeDocumentSummary],
    summary="Parsed artifacts stored for this user's company",
)
@log_execution(logger)
async def list_documents(
    user_id: str = Query(..., description="Scope is derived from this user"),
    limit: int = Query(50, ge=1, le=200),
) -> list[KnowledgeDocumentSummary]:
    """What can be re-extracted without re-parsing."""
    scope_id = await resolve_scope_id(user_id)
    rows = await _store.list_documents(scope_id, limit)
    return [
        KnowledgeDocumentSummary(
            knowledge_document_id=r.id,
            doc_id=r.doc_id,
            document_id=r.document_id,
            n_pages=r.n_pages or 0,
            n_chunks=len((r.artifact or {}).get("chunks") or []),
            schema_version=r.schema_version or "",
            parser=f"{r.parser_name}/{r.parser_backend or ''}".rstrip("/"),
            content_hash=r.content_hash,
            created_at=r.created_at,
        )
        for r in rows
    ]


@router.post(
    "/documents/{knowledge_document_id}/extract",
    response_model=IngestAccepted,
    status_code=status.HTTP_202_ACCEPTED,
    summary="Re-extract a stored artifact (no re-parsing)",
)
@limiter.limit("5/minute")
@log_execution(logger)
async def reextract(
    request: Request,
    knowledge_document_id: str,
    user_id: str = Query(..., description="Scope is derived from this user"),
) -> IngestAccepted:
    """Re-run extraction over an artifact already in the database.

    The common case, and the reason it exists: prompt retuning must not re-pay
    the parser for a byte-identical artifact. Async like `/ingest` — extraction
    alone is ~170 s for nine pages — so poll `GET /jobs/{job_id}`.
    """
    job, reused = await _service.start_reextract(user_id, knowledge_document_id)
    if reused:
        message = "A job for this scope is already running; returning it."
    elif job.status == "failed":
        message = job.error_message or "Nothing to extract."
    else:
        message = "Re-extracting the stored artifact."
    return IngestAccepted(
        job_id=job.id,
        status=job.status,
        stage=job.stage,
        n_requested=job.n_requested,
        reused=reused,
        skipped=[],
        message=message,
    )


@router.get(
    "/entries",
    response_model=list[EntrySummary],
    summary="Candidate knowledge entries",
)
@log_execution(logger)
async def list_entries(
    user_id: str = Query(..., description="Scope is derived from this user"),
    doc_id: str | None = Query(None, description="Filter to one document"),
    kind: Literal["glossary", "rule", "formula", "domain"] | None = Query(None),
    limit: int = Query(200, ge=1, le=1000),
) -> list[EntrySummary]:
    """The raw artifact read, annotated with any decision already recorded."""
    scope_id = await resolve_scope_id(user_id)
    rows = await _store.list_entries(
        scope_id=scope_id, doc_id=doc_id, kind=kind, limit=limit
    )
    reviews = await _store.latest_reviews(scope_id, [r.entity_id for r in rows])
    return [
        EntrySummary(
            entity_id=r.entity_id,
            kind=r.kind,
            label=r.label,
            mention_count=r.mention_count or 0,
            extraction_status=r.extraction_status,
            diff_status=r.diff_status,
            definition_conflict=bool(r.definition_conflict),
            payload=r.payload,
            review=_review_summary(reviews.get(r.entity_id)),
        )
        for r in rows
    ]


@router.get(
    "/queue",
    summary="The review queue — most-decision-worthy first",
)
@log_execution(logger)
async def review_queue(
    user_id: str = Query(..., description="Scope is derived from this user"),
    doc_id: str | None = Query(None, description="Filter to one document"),
) -> list[dict]:
    """Rows an expert works through, in order.

    Derived at read time by the pipeline's own `build_queue`, never stored:
    persisting a derived ordering creates a second truth that drifts from the
    first. Reusing that function rather than re-sorting here is what keeps the
    endpoint and the CLI showing the same queue.

    Rows carry `row_kind` (`term` | `key_parameter`) and a consumer must switch
    on it: an unresolved key parameter has a surface and no term, no definition
    and no mention count.
    """
    scope_id = await resolve_scope_id(user_id)
    glossary = await _store.list_entries(
        scope_id=scope_id, doc_id=doc_id, kind="glossary", limit=1000
    )
    domain_rows = await _store.list_entries(
        scope_id=scope_id, doc_id=doc_id, kind="domain", limit=1
    )
    domain = domain_rows[0].payload if domain_rows else None

    rows = build_queue([r.payload for r in glossary], domain)
    reviews = await _store.latest_reviews(scope_id)
    for row in rows:
        # `term_id` on a term row, absent on a key_parameter row.
        row["review"] = _review_summary(reviews.get(row.get("term_id") or ""))
    return rows


@router.post(
    "/entries/{entity_id}/reviews",
    response_model=ReviewAccepted,
    status_code=status.HTTP_201_CREATED,
    summary="Record an expert decision on one entry",
)
@log_execution(logger)
async def record_review(
    entity_id: str, payload: ReviewRequest, user_id: str = Query(...)
) -> ReviewAccepted:
    """Approve, edit or reject one candidate. APPEND-ONLY.

    Keyed on `entity_id`, not the entry's row id: `entity_id` is deterministic
    and content-derived, so it survives re-extraction while row ids do not. That
    is what lets an expert's approvals outlive a prompt retune.

    `content_hash` is derived server-side from the artifact the entry came from,
    never taken from the request — a stale client would otherwise attribute a
    ruling to the wrong artifact version.

    ⚠️ Approved and edited entries become the baseline a later extraction diffs
    against (`approved_glossary`), so an `edited_payload` written here can reach
    a future prompt. On an unauthenticated route that is a content-injection
    path, and it is the strongest argument for putting real auth in front of
    this surface (DEV_PLAN #43) before an expert relies on it.
    """
    if payload.decision == "edited" and not payload.edited_payload:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="decision 'edited' requires edited_payload.",
        )
    scope_id = await resolve_scope_id(user_id)
    try:
        row = await _store.save_review(
            entity_id=entity_id,
            scope_id=scope_id,
            decision=payload.decision,
            reviewer_id=payload.reviewer_id,
            edited_payload=payload.edited_payload,
            note=payload.note,
        )
    except LookupError as e:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"No entry {entity_id} in this scope.",
        ) from e

    # The review IS the invalidation event. Without this the expert approves
    # something and the planner keeps reading the pre-approval card for up to an
    # hour, which makes the loop look broken in exactly the way that is hardest
    # to debug — the write succeeded and nothing changed.
    await _knowledge.invalidate(scope_id)

    return ReviewAccepted(
        review_id=row.id,
        entity_id=entity_id,
        decision=row.decision,
        content_hash=row.content_hash,
        message=f"Decision '{row.decision}' recorded.",
    )


def _review_summary(row) -> dict | None:
    """The decision a caller needs to see beside a row, without the payload."""
    if row is None:
        return None
    return {
        "decision": row.decision,
        "reviewer_id": row.reviewer_id,
        "content_hash": row.content_hash,
        "note": row.note,
        "created_at": row.created_at.isoformat() if row.created_at else None,
    }

# ── The domain declaration (V4-9 / V4-10) ────────────────────────────────
#
# The DECLARED half of a domain context: what it is, and what it deliberately is
# not. Derived where it can be (the boundary is the complement of the covered
# subdomains over a closed enum — checkable, unlike a model-written sentence),
# left empty where only a human can answer.
#
# There is no new review machinery here on purpose. A declaration is stored as a
# `kind='domain'` entry, so an expert approves or corrects it through the SAME
# `POST /entries/{entity_id}/reviews` route as a glossary term.


@router.post(
    "/domain/propose",
    status_code=status.HTTP_201_CREATED,
    summary="Draft this company's domain declaration for review",
)
@limiter.limit("10/minute")
@log_execution(logger)
async def propose_domain(request: Request, user_id: str = Query(...)) -> dict:
    """Derive a draft declaration and store it awaiting review.

    **Calls no model.** Everything is derived from what the corpus demonstrably
    contains, so nothing in the draft can be wrong in a way a reviewer would
    have to detect rather than simply complete. Re-proposing replaces the
    standing draft; the expert's decisions key on `entity_id` and survive it.

    The result reaches no planner until it is approved.
    """
    payload = await _knowledge.propose_declaration(user_id)
    return {
        "entity_id": payload["domain_id"],
        "declaration": payload,
        "message": (
            "Draft stored. Approve or correct it via "
            f"POST /api/v1/knowledge/entries/{payload['domain_id']}/reviews"
        ),
    }


@router.get(
    "/domain",
    summary="The domain context this company's agents would read",
)
@log_execution(logger)
async def get_domain(
    user_id: str = Query(...),
    rendered: bool = Query(False, description="Return the prompt text instead of the object"),
) -> dict:
    """The composed domain context, plus the standing declaration if there is one.

    `declaration_approved` is the field to read: until it is true the domain has
    no name and no boundary, and a planner cannot refuse on domain grounds.
    """
    context = await _knowledge.get_context(user_id)
    declaration = await _knowledge.get_declaration(user_id)
    return {
        "scope_id": context.scope_id,
        "declaration": declaration,
        "declaration_approved": context.authority.coverage.declared,
        "n_measures": len(context.measures),
        "coverage": context.authority.coverage.model_dump(),
        "context": None if rendered else context.model_dump(mode="json"),
        "card": await _knowledge.render_context(user_id) if rendered else None,
    }