"""
Kommentarer/bilder på frittstående runder (ADR-044) -- "Banter Board" for
en enkelt runde (`round`/migrasjon 020), pluss en samlet `/feed`-side som
aggregerer disse på tvers av runder brukeren har innsyn i.

To bevisste forskjeller fra org-feeden (`messaging.py`, ADR-025):

- Egen `round_message`-tabell (migrasjon 058), IKKE en utvidelse av den
  org-scopede `message`-tabellen -- `round` har verken `organization_id`
  eller RLS (ADR-033 Beslutning A), så all autorisasjon her skjer i
  app-laget via `plain_connection()`, ikke database-policy.
- Skriverett = leserett: ALLE som kan SE runden (`_can_view_round`,
  gjenbrukt uendret fra `rounds.py`, ADR-036 fase 2) kan også POSTE --
  samme "kan se = kan bidra"-modell som org-feeden, men her er
  synlighetssjekken allerede bygget og trenger ingen egen
  medlemskaps-/deltakelses-sjekk i tillegg.

Sanntid: INGEN egen WebSocket-kanal. Gjenbruker `broadcast_round_update`
(app/realtime.py), som allerede kringkastes ved hver hull-endring og
allerede konsumeres av `/ws/rounds/{id}/live` / `/ws/public/rounds/{id}/
live` -- klienten reagerer med å hente meldingslisten på nytt, samme
"noe endret seg"-mønster som resten av runde-sanntiden.
"""

from datetime import datetime

from fastapi import APIRouter, Depends, File, Form, Query, UploadFile
from pydantic import BaseModel

from .. import storage
from ..auth import CurrentUser, get_current_user, get_current_user_optional
from ..db import plain_connection
from ..errors import app_error, translate_db_errors
from ..realtime import broadcast_round_update
from .rounds import _get_viewable_round_or_404, _resolve_round_message_author_name

router = APIRouter(tags=["round-messages"])

_ROUND_MESSAGE_COLUMNS = """
    id::text, round_id::text, author_user_id::text, author_display_name, body, image_key, created_at
"""

# ADR-046: ett fast, kuratert reaksjonssett -- "like (eller andre emojier)",
# ikke et fritt emoji-utvalg. Delt med messaging.py (importert derfra).
ALLOWED_REACTION_EMOJIS = {"👍", "❤️", "😂", "😮", "😢", "🙏"}


class ReactionIn(BaseModel):
    emoji: str


class ReactionSummary(BaseModel):
    emoji: str
    count: int
    reacted_by_me: bool
    # Fulle navn (roster-kontekst, ikke direkte adressering -- CLAUDE.md
    # navneformat-regel), i rekkefølgen de reagerte -- brukeren ba
    # eksplisitt 2026-08-07 om å kunne se HVEM som reagerte, ikke bare et
    # antall. Hentes i SAMME grupperte batch-spørring som selve
    # oppsummeringen (array_agg), ingen ekstra tur-retur ved visning.
    reactors: list[str] = []


class RoundMessageOut(BaseModel):
    id: str
    round_id: str
    author_user_id: str
    author_display_name: str
    body: str | None
    image_url: str | None
    created_at: str
    reactions: list[ReactionSummary] = []
    comment_count: int = 0


def _row_to_round_message(
    row, reactions: list[ReactionSummary] | None = None, comment_count: int = 0
) -> RoundMessageOut:
    return RoundMessageOut(
        id=row["id"],
        round_id=row["round_id"],
        author_user_id=row["author_user_id"],
        author_display_name=row["author_display_name"],
        body=row["body"],
        image_url=storage.public_url(row["image_key"]) if row["image_key"] else None,
        created_at=row["created_at"].isoformat(),
        reactions=reactions or [],
        comment_count=comment_count,
    )


async def _round_message_reactions(
    conn, message_ids: list[str], viewer_user_id: str | None
) -> dict[str, list[ReactionSummary]]:
    """Grupperte reaksjonsoppsummeringer for en batch med round_message-ID-er
    -- unngår N+1 når en meldingsliste rendres."""
    if not message_ids:
        return {}
    rows = await conn.fetch(
        """
        SELECT rmr.round_message_id::text AS message_id, rmr.emoji, count(*) AS count,
               COALESCE(bool_or(rmr.user_id = $2), false) AS reacted_by_me,
               array_agg(
                   COALESCE(NULLIF(btrim(au.first_name || ' ' || au.last_name), ''), au.display_name)
                   ORDER BY rmr.created_at
               ) AS reactors
        FROM round_message_reaction rmr
        JOIN app_user au ON au.id = rmr.user_id
        WHERE rmr.round_message_id = ANY($1::uuid[])
        GROUP BY rmr.round_message_id, rmr.emoji
        """,
        message_ids,
        viewer_user_id,
    )
    result: dict[str, list[ReactionSummary]] = {}
    for r in rows:
        result.setdefault(r["message_id"], []).append(
            ReactionSummary(
                emoji=r["emoji"],
                count=r["count"],
                reacted_by_me=r["reacted_by_me"],
                reactors=list(r["reactors"]),
            )
        )
    return result


async def _round_message_comment_counts(conn, message_ids: list[str]) -> dict[str, int]:
    if not message_ids:
        return {}
    rows = await conn.fetch(
        """
        SELECT round_message_id::text AS message_id, count(*) AS count
        FROM round_message_comment
        WHERE round_message_id = ANY($1::uuid[])
        GROUP BY round_message_id
        """,
        message_ids,
    )
    return {r["message_id"]: r["count"] for r in rows}


# ---------------------------------------------------------------------------
# Runde-nivå kommentarer/bilder
# ---------------------------------------------------------------------------


@router.get("/rounds/{round_id}/messages", response_model=list[RoundMessageOut])
async def list_round_messages(
    round_id: str,
    user: CurrentUser | None = Depends(get_current_user_optional),
) -> list[RoundMessageOut]:
    async with plain_connection() as conn:
        await _get_viewable_round_or_404(conn, round_id, user.user_id if user else None)
        # Nyeste øverst (2026-08-06, brukerens eksplisitte ønske) -- dette
        # er en oppdateringsstrøm om runden, ikke en samtale man leser
        # kronologisk fra start (ulikt lag-chatten, som beholder eldst-
        # først -- se app/routers/messaging.py).
        rows = await conn.fetch(
            f"SELECT {_ROUND_MESSAGE_COLUMNS} FROM round_message WHERE round_id = $1 ORDER BY created_at DESC",
            round_id,
        )
        message_ids = [r["id"] for r in rows]
        reactions_by_id = await _round_message_reactions(conn, message_ids, user.user_id if user else None)
        comment_counts = await _round_message_comment_counts(conn, message_ids)
    return [
        _row_to_round_message(r, reactions_by_id.get(r["id"]), comment_counts.get(r["id"], 0))
        for r in rows
    ]


@router.post("/rounds/{round_id}/messages", response_model=RoundMessageOut, status_code=201)
async def post_round_message(
    round_id: str,
    body: str | None = Form(default=None),
    image: UploadFile | None = File(default=None),
    user: CurrentUser = Depends(get_current_user),
) -> RoundMessageOut:
    if not body and image is None:
        raise app_error(400, "VALIDATION_FAILED", "Meldingen må ha tekst eller bilde.")
    raw = await storage.read_optional_image(image)

    async with plain_connection() as conn, translate_db_errors():
        # Selve synlighetssjekken ER post-sjekken -- "kan se = kan bidra",
        # ingen snevrere gate i tillegg (ADR-044 Beslutning A).
        await _get_viewable_round_or_404(conn, round_id, user.user_id)

        image_key = None
        if raw is not None:
            try:
                image_key = await storage.upload_image("round_messages", round_id, raw)
            except storage.InvalidImageError:
                raise app_error(400, "VALIDATION_FAILED", "Filen er ikke et gyldig bilde.")

        display_name = await _resolve_round_message_author_name(conn, user.user_id)

        row = await conn.fetchrow(
            f"""
            INSERT INTO round_message (round_id, author_user_id, author_display_name, body, image_key)
            VALUES ($1, $2, $3, $4, $5)
            RETURNING {_ROUND_MESSAGE_COLUMNS}
            """,
            round_id,
            user.user_id,
            display_name,
            body,
            image_key,
        )
    message = _row_to_round_message(row)
    await broadcast_round_update(round_id)
    return message


@router.delete("/rounds/{round_id}/messages/{message_id}", status_code=204)
async def delete_round_message(
    round_id: str,
    message_id: str,
    user: CurrentUser = Depends(get_current_user),
) -> None:
    """Forfatteren selv, ELLER rundens eier (moderering -- rundens analog
    til org-admin), samme modell som org-feedens `delete_feed_message`."""
    async with plain_connection() as conn:
        row = await conn.fetchrow(
            """
            SELECT rm.author_user_id::text AS author_user_id, r.owner_user_id::text AS owner_user_id
            FROM round_message rm JOIN round r ON r.id = rm.round_id
            WHERE rm.id = $1 AND rm.round_id = $2
            """,
            message_id,
            round_id,
        )
        if row is None:
            raise app_error(404, "NOT_FOUND", "Innlegget finnes ikke.")
        if user.user_id not in (row["author_user_id"], row["owner_user_id"]):
            raise app_error(
                403,
                "NOT_MESSAGE_AUTHOR",
                "Du kan kun slette dine egne innlegg (eller som rundeeier).",
            )
        await conn.execute("DELETE FROM round_message WHERE id = $1", message_id)
    await broadcast_round_update(round_id)


# ---------------------------------------------------------------------------
# Reaksjoner (ADR-046) -- "kan se = kan bidra", samme som selve innlegget.
# ---------------------------------------------------------------------------


async def _get_round_message_or_404(conn, round_id: str, message_id: str) -> None:
    exists = await conn.fetchval(
        "SELECT id FROM round_message WHERE id = $1 AND round_id = $2", message_id, round_id
    )
    if exists is None:
        raise app_error(404, "NOT_FOUND", "Innlegget finnes ikke.")


@router.put("/rounds/{round_id}/messages/{message_id}/reaction", response_model=list[ReactionSummary])
async def set_round_message_reaction(
    round_id: str,
    message_id: str,
    payload: ReactionIn,
    user: CurrentUser = Depends(get_current_user),
) -> list[ReactionSummary]:
    if payload.emoji not in ALLOWED_REACTION_EMOJIS:
        raise app_error(400, "VALIDATION_FAILED", "Ugyldig emoji.")
    async with plain_connection() as conn:
        await _get_viewable_round_or_404(conn, round_id, user.user_id)
        await _get_round_message_or_404(conn, round_id, message_id)
        # Én reaksjon per bruker per innlegg -- bytte av emoji erstatter,
        # stables ikke (ADR-046).
        await conn.execute(
            """
            INSERT INTO round_message_reaction (round_message_id, user_id, emoji)
            VALUES ($1, $2, $3)
            ON CONFLICT (round_message_id, user_id) DO UPDATE SET emoji = EXCLUDED.emoji, created_at = now()
            """,
            message_id,
            user.user_id,
            payload.emoji,
        )
        summaries = await _round_message_reactions(conn, [message_id], user.user_id)
    return summaries.get(message_id, [])


@router.delete("/rounds/{round_id}/messages/{message_id}/reaction", response_model=list[ReactionSummary])
async def remove_round_message_reaction(
    round_id: str,
    message_id: str,
    user: CurrentUser = Depends(get_current_user),
) -> list[ReactionSummary]:
    async with plain_connection() as conn:
        await _get_viewable_round_or_404(conn, round_id, user.user_id)
        await _get_round_message_or_404(conn, round_id, message_id)
        await conn.execute(
            "DELETE FROM round_message_reaction WHERE round_message_id = $1 AND user_id = $2",
            message_id,
            user.user_id,
        )
        summaries = await _round_message_reactions(conn, [message_id], user.user_id)
    return summaries.get(message_id, [])


# ---------------------------------------------------------------------------
# Trådede kommentarer (ADR-046) -- flat lagring (parent_comment_id), frontend
# bygger tre-strukturen. Kronologisk (eldst først) -- en samtaletråd leses
# top-til-bunn, ulikt de kronologisk OMVENDTE innleggs-/meldingsstrømmene
# ("nyeste først, over alt", 2026-08-06) som dette henger under.
# ---------------------------------------------------------------------------

_ROUND_MESSAGE_COMMENT_COLUMNS = """
    id::text, round_message_id::text, parent_comment_id::text, author_user_id::text,
    author_display_name, body, created_at
"""


class CommentIn(BaseModel):
    body: str
    parent_comment_id: str | None = None


class CommentOut(BaseModel):
    id: str
    round_message_id: str
    parent_comment_id: str | None
    author_user_id: str
    author_display_name: str
    body: str
    created_at: str


def _row_to_round_message_comment(row) -> CommentOut:
    return CommentOut(
        id=row["id"],
        round_message_id=row["round_message_id"],
        parent_comment_id=row["parent_comment_id"],
        author_user_id=row["author_user_id"],
        author_display_name=row["author_display_name"],
        body=row["body"],
        created_at=row["created_at"].isoformat(),
    )


@router.get("/rounds/{round_id}/messages/{message_id}/comments", response_model=list[CommentOut])
async def list_round_message_comments(
    round_id: str,
    message_id: str,
    user: CurrentUser | None = Depends(get_current_user_optional),
) -> list[CommentOut]:
    async with plain_connection() as conn:
        await _get_viewable_round_or_404(conn, round_id, user.user_id if user else None)
        await _get_round_message_or_404(conn, round_id, message_id)
        rows = await conn.fetch(
            f"""
            SELECT {_ROUND_MESSAGE_COMMENT_COLUMNS} FROM round_message_comment
            WHERE round_message_id = $1 ORDER BY created_at ASC
            """,
            message_id,
        )
    return [_row_to_round_message_comment(r) for r in rows]


@router.post(
    "/rounds/{round_id}/messages/{message_id}/comments", response_model=CommentOut, status_code=201
)
async def post_round_message_comment(
    round_id: str,
    message_id: str,
    payload: CommentIn,
    user: CurrentUser = Depends(get_current_user),
) -> CommentOut:
    body = payload.body.strip()
    if not body:
        raise app_error(400, "VALIDATION_FAILED", "Kommentaren kan ikke være tom.")

    async with plain_connection() as conn, translate_db_errors():
        await _get_viewable_round_or_404(conn, round_id, user.user_id)
        await _get_round_message_or_404(conn, round_id, message_id)
        if payload.parent_comment_id is not None:
            parent_exists = await conn.fetchval(
                "SELECT id FROM round_message_comment WHERE id = $1 AND round_message_id = $2",
                payload.parent_comment_id,
                message_id,
            )
            if parent_exists is None:
                raise app_error(404, "NOT_FOUND", "Kommentaren du svarer på finnes ikke.")

        display_name = await _resolve_round_message_author_name(conn, user.user_id)
        row = await conn.fetchrow(
            f"""
            INSERT INTO round_message_comment
                (round_message_id, parent_comment_id, author_user_id, author_display_name, body)
            VALUES ($1, $2, $3, $4, $5)
            RETURNING {_ROUND_MESSAGE_COMMENT_COLUMNS}
            """,
            message_id,
            payload.parent_comment_id,
            user.user_id,
            display_name,
            body,
        )
    comment = _row_to_round_message_comment(row)
    # INGEN broadcast_round_update her (ADR-046) -- kommentarer/reaksjoner
    # har bevisst ingen live-push til andre samtidige seere i v1 (kun egen
    # handling refetcher). Ville ellers trigget RoundMessages sin
    # "noe endret seg"-refetch for ALLE meldinger på siden ved hver eneste
    # kommentar, og med det kollapset enhver allerede utvidet tråd andre
    # steder på siden -- utilsiktet UX-regresjon oppdaget under
    # nettleserverifisering.
    return comment


@router.delete("/rounds/{round_id}/messages/{message_id}/comments/{comment_id}", status_code=204)
async def delete_round_message_comment(
    round_id: str,
    message_id: str,
    comment_id: str,
    user: CurrentUser = Depends(get_current_user),
) -> None:
    """Forfatteren selv, ELLER rundens eier -- samme modell som selve
    innlegget (`delete_round_message`). Kaskade-sletter eventuelle svar
    under (FK ON DELETE CASCADE, ADR-046)."""
    async with plain_connection() as conn:
        row = await conn.fetchrow(
            """
            SELECT c.author_user_id::text AS author_user_id, r.owner_user_id::text AS owner_user_id
            FROM round_message_comment c
            JOIN round_message rm ON rm.id = c.round_message_id
            JOIN round r ON r.id = rm.round_id
            WHERE c.id = $1 AND c.round_message_id = $2 AND rm.round_id = $3
            """,
            comment_id,
            message_id,
            round_id,
        )
        if row is None:
            raise app_error(404, "NOT_FOUND", "Kommentaren finnes ikke.")
        if user.user_id not in (row["author_user_id"], row["owner_user_id"]):
            raise app_error(
                403,
                "NOT_COMMENT_AUTHOR",
                "Du kan kun slette dine egne kommentarer (eller som rundeeier).",
            )
        await conn.execute("DELETE FROM round_message_comment WHERE id = $1", comment_id)
    # INGEN broadcast_round_update her -- se samme begrunnelse i
    # post_round_message_comment over.


# ---------------------------------------------------------------------------
# Samlet feed -- egne runder + venners synlige runder (ADR-036 fase 2)
# ---------------------------------------------------------------------------


class FeedEntryOut(BaseModel):
    id: str
    round_id: str
    round_owner_user_id: str
    round_owner_display_name: str
    course_name: str
    played_at: str
    author_user_id: str
    author_display_name: str
    body: str | None
    image_url: str | None
    created_at: str
    reactions: list[ReactionSummary] = []
    comment_count: int = 0


@router.get("/feed", response_model=list[FeedEntryOut])
async def get_feed(
    before: datetime | None = Query(default=None),
    limit: int = Query(default=20, ge=1, le=50),
    user: CurrentUser = Depends(get_current_user),
) -> list[FeedEntryOut]:
    # Reverst av `_can_view_round` (starter fra VIEWEREN, ikke fra
    # rundeeieren) -- samme retning og samme 'friends'-predikat som
    # `list_friends_on_course` (rounds.py), kopiert inn her i stedet for
    # faktorisert ut, samme bevisste "grei duplisering på denne skalaen"
    # begrunnelse som der (se rounds.py sin kommentar over
    # `list_friends_on_course`). Justeringer mot den funksjonen: egne
    # runder er ALLTID med (uansett visibility_mode), ingen "spiller
    # nå/siste 24t"-filter -- dette er en all-time, paginert liste av
    # round_message-rader, ikke en "hvem er live nå"-widget.
    async with plain_connection() as conn:
        rows = await conn.fetch(
            """
            SELECT rm.id::text AS id, rm.round_id::text AS round_id,
                   r.owner_user_id::text AS round_owner_user_id,
                   COALESCE(owner.first_name || ' ' || owner.last_name, owner.display_name) AS round_owner_display_name,
                   r.course_name_snapshot AS course_name, r.played_at,
                   rm.author_user_id::text AS author_user_id, rm.author_display_name,
                   rm.body, rm.image_key, rm.created_at
            FROM round_message rm
            JOIN round r ON r.id = rm.round_id
            JOIN app_user owner ON owner.id = r.owner_user_id
            WHERE (
                r.owner_user_id = $1
                OR EXISTS (
                    SELECT 1 FROM round_participant rp
                    WHERE rp.round_id = r.id AND rp.user_id = $1
                )
                OR r.visibility_mode = 'public'
                OR (
                    r.visibility_mode = 'friends'
                    AND EXISTS (
                        SELECT 1 FROM friendship f
                        WHERE f.status = 'accepted'
                          AND ((f.requester_user_id = $1 AND f.addressee_user_id = r.owner_user_id)
                            OR (f.requester_user_id = r.owner_user_id AND f.addressee_user_id = $1))
                    )
                    AND EXISTS (
                        SELECT 1 FROM friend_categorization fc
                        WHERE fc.owner_user_id = r.owner_user_id AND fc.friend_user_id = $1
                    )
                    AND NOT EXISTS (
                        SELECT 1 FROM friend_categorization fc
                        WHERE fc.owner_user_id = r.owner_user_id AND fc.friend_user_id = $1
                          AND fc.category NOT IN (
                              SELECT category FROM round_visible_category WHERE round_id = r.id
                          )
                    )
                )
            )
            AND ($2::timestamptz IS NULL OR rm.created_at < $2::timestamptz)
            ORDER BY rm.created_at DESC
            LIMIT $3
            """,
            user.user_id,
            before,
            limit,
        )
        entry_ids = [r["id"] for r in rows]
        reactions_by_id = await _round_message_reactions(conn, entry_ids, user.user_id)
        comment_counts = await _round_message_comment_counts(conn, entry_ids)
    return [
        FeedEntryOut(
            id=r["id"],
            round_id=r["round_id"],
            round_owner_user_id=r["round_owner_user_id"],
            round_owner_display_name=r["round_owner_display_name"],
            course_name=r["course_name"],
            played_at=r["played_at"].isoformat(),
            author_user_id=r["author_user_id"],
            author_display_name=r["author_display_name"],
            body=r["body"],
            image_url=storage.public_url(r["image_key"]) if r["image_key"] else None,
            created_at=r["created_at"].isoformat(),
            reactions=reactions_by_id.get(r["id"], []),
            comment_count=comment_counts.get(r["id"], 0),
        )
        for r in rows
    ]