"""FlowDeck — Collaboration API (v4.9.0): inline comments on pages + mentions.

Comments live in the existing `comments` table, extended with a target_type /
target_id pair and inline anchors (anchor_block_id + text offsets). Mentions
written in a comment body automatically notify the mentioned users.
"""
from __future__ import annotations

import logging

from fastapi import APIRouter, HTTPException, Request

from app.auth.session import SessionManager
from app.db import get_conn
from app.services import notifications as notif

logger = logging.getLogger(__name__)
router = APIRouter(tags=["collaboration"], prefix="/api")


def _current_user(request: Request) -> dict:
    user = SessionManager.decode_session(request.cookies.get("flowdeck_session", ""))
    if not user or not user.get("id"):
        raise HTTPException(status_code=401, detail="Authentication required")
    return user


def _page_url(page_id: int) -> str:
    from app.config import settings
    return f"{settings.app_base_url}/pages/{page_id}"


def _serialize(rows):
    out = []
    for r in rows:
        d = dict(r)
        d["author"] = {
            "id": r["author_id"],
            "login": r["author_login"],
            "full_name": r["author_name"],
            "avatar_url": r["author_avatar"],
            "avatar_color": r["author_color"],
        }
        for k in ("author_id", "author_login", "author_name", "author_avatar", "author_color"):
            d.pop(k, None)
        out.append(d)
    return out


@router.get("/pages/{page_id}/comments")
async def list_comments(request: Request, page_id: int):
    """List page-level and inline comments for a FlowDeck page."""
    _current_user(request)
    with get_conn() as conn:
        page = conn.execute("SELECT id, title FROM pages WHERE id=?", (page_id,)).fetchone()
        if not page:
            raise HTTPException(404, "Page not found")
        rows = conn.execute(
            """SELECT c.*, c.user_id AS author_id, u.login AS author_login,
                      u.full_name AS author_name, u.avatar_url AS author_avatar,
                      u.avatar_color AS author_color
               FROM comments c
               JOIN users u ON c.user_id = u.id
               WHERE c.target_type='page' AND c.target_id=?
               ORDER BY c.created_at ASC, c.id ASC""",
            (page_id,),
        ).fetchall()
    return {"page_id": page_id, "comments": _serialize(rows)}


@router.post("/pages/{page_id}/comments")
async def add_comment(request: Request, page_id: int):
    """Create a page or inline comment. Mentions (@login) notify users."""
    user = _current_user(request)
    body = await request.json() if request.headers.get("content-type") else {}
    text = (body.get("body") or "").strip()
    if not text:
        raise HTTPException(400, "body required")

    anchor_block = body.get("anchor_block_id")
    anchor_start = body.get("anchor_start")
    anchor_end = body.get("anchor_end")
    # normalize empty anchor → page-level comment
    if not anchor_block or anchor_start is None or anchor_end is None:
        anchor_block, anchor_start, anchor_end = None, None, None
    elif int(anchor_start) == int(anchor_end):
        anchor_block, anchor_start, anchor_end = None, None, None

    parent_id = body.get("parent_id")
    uid = user["id"]
    with get_conn() as conn:
        page = conn.execute("SELECT id, title FROM pages WHERE id=?", (page_id,)).fetchone()
        if not page:
            raise HTTPException(404, "Page not found")
        conn.execute(
            "INSERT OR IGNORE INTO users (id, login, full_name, is_admin) VALUES (?,?,?,1)",
            (uid, user.get("login", "admin"), user.get("full_name", "Admin")),
        )
        cur = conn.execute(
            """INSERT INTO comments
               (page_id, user_id, body, parent_id, target_type, target_id,
                anchor_block_id, anchor_start, anchor_end)
               VALUES (?,?,?,?, 'page', ?, ?, ?, ?)""",
            (page_id, uid, text, parent_id, page_id, anchor_block, anchor_start, anchor_end),
        )
        comment_id = cur.lastrowid
        conn.commit()

        # Notify users @-mentioned in the comment (skip the author).
        url = _page_url(page_id)
        title = f"New comment on “{page['title']}”"
        message = f"{user.get('full_name') or user.get('login')} commented: {text[:300]}"
        notif.process_mentions(
            text, uid, "mention", title, message,
            "page", page_id, url, conn=conn,
        )
        conn.commit()

    return {"id": comment_id, "status": "created"}


@router.post("/pages/{page_id}/mentions")
async def notify_page_mentions(request: Request, page_id: int):
    """Notify users @-mentioned in a page's content (called on save).

    Accepts {"text": "..."} containing @login handles. Deduplicated server-side
    against a per-page cache so repeated auto-saves don't spam notifications.
    """
    user = _current_user(request)
    body = await request.json() if request.headers.get("content-type") else {}
    text = body.get("text") or ""
    with get_conn() as conn:
        page = conn.execute("SELECT id, title FROM pages WHERE id=?", (page_id,)).fetchone()
        if not page:
            raise HTTPException(404, "Page not found")
        url = _page_url(page_id)
        mentioned = notif.process_mentions(
            text, user["id"], "mention", f"You were mentioned in “{page['title']}”",
            f"{user.get('full_name') or user.get('login')} mentioned you on a page.",
            "page", page_id, url, conn=conn,
        )
        conn.commit()
    return {"mentioned": mentioned}


@router.put("/comments/{comment_id}")
async def update_comment(request: Request, comment_id: int):
    """Update a comment body or resolve/unresolve it."""
    user = _current_user(request)
    body = await request.json() if request.headers.get("content-type") else {}
    with get_conn() as conn:
        row = conn.execute(
            "SELECT * FROM comments WHERE id=?", (comment_id,)
        ).fetchone()
        if not row:
            raise HTTPException(404, "Comment not found")
        if row["user_id"] != user["id"]:
            raise HTTPException(403, "Not allowed to edit this comment")
        if "body" in body and body.get("body") is not None:
            conn.execute(
                "UPDATE comments SET body=?, updated_at=CURRENT_TIMESTAMP WHERE id=?",
                (body["body"].strip(), comment_id),
            )
        if "resolved" in body and body.get("resolved") is not None:
            conn.execute("UPDATE comments SET resolved=? WHERE id=?",
                         (1 if body["resolved"] else 0, comment_id))
        conn.commit()
    return {"id": comment_id, "status": "updated"}


@router.delete("/comments/{comment_id}")
async def delete_comment(request: Request, comment_id: int):
    """Delete a comment and its replies."""
    user = _current_user(request)
    with get_conn() as conn:
        row = conn.execute("SELECT * FROM comments WHERE id=?", (comment_id,)).fetchone()
        if not row:
            raise HTTPException(404, "Comment not found")
        if row["user_id"] != user["id"]:
            # allow page "owners" — fall back to a simple ownership rule for now
            raise HTTPException(403, "Not allowed to delete this comment")
        conn.execute("DELETE FROM comments WHERE id=? OR parent_id=?", (comment_id, comment_id))
        conn.commit()
    return {"id": comment_id, "status": "deleted"}