"""FlowDeck — v5.14.0 Synced blocks: a block created once, displayed
and edited across multiple pages.

The ``synced_blocks`` table stores the source-of-truth content. Each
page that uses a synced block stores a reference in ``page_synced_blocks``.
Editing the source propagates to all referencing pages (via realtime
rooms or on next load).
"""
from __future__ import annotations

import json
import logging
import uuid

from app.db import get_conn

logger = logging.getLogger(__name__)


def block_id() -> str:
    return "sb" + uuid.uuid4().hex[:10]


# ── SyncedBlock CRUD ──────────────────────────────────────────────

def create_synced_block(workspace: str, title: str, content: list[dict],
                        created_by: int | None = None) -> int:
    """Create a new synced block and return its id."""
    content_json = json.dumps(content, ensure_ascii=False) if content else "[]"
    with get_conn() as conn:
        cur = conn.execute(
            """INSERT INTO synced_blocks (title, content, created_by, workspace)
               VALUES (?, ?, ?, ?)""",
            (title, content_json, created_by, workspace),
        )
        conn.commit()
        return cur.lastrowid


def get_synced_block(synced_id: int) -> dict | None:
    """Fetch a synced block by id."""
    with get_conn() as conn:
        row = conn.execute(
            "SELECT * FROM synced_blocks WHERE id=?", (synced_id,)
        ).fetchone()
    if not row:
        return None
    return dict(row)


def update_synced_block(synced_id: int, title: str,
                        content: list[dict]) -> None:
    """Update a synced block's title and content."""
    content_json = json.dumps(content, ensure_ascii=False)
    with get_conn() as conn:
        conn.execute(
            """UPDATE synced_blocks SET title=?, content=?,
               updated_at=CURRENT_TIMESTAMP WHERE id=?""",
            (title, content_json, synced_id),
        )
        conn.commit()


def delete_synced_block(synced_id: int) -> None:
    """Delete a synced block (cascades via FK)."""
    with get_conn() as conn:
        conn.execute("DELETE FROM synced_blocks WHERE id=?", (synced_id,))
        conn.commit()


def list_synced_blocks(workspace: str) -> list[dict]:
    """List all synced blocks in a workspace."""
    with get_conn() as conn:
        rows = conn.execute(
            "SELECT * FROM synced_blocks WHERE workspace=? ORDER BY updated_at DESC",
            (workspace,),
        ).fetchall()
    return [dict(r) for r in rows]


# ── Page references ───────────────────────────────────────────────

def add_page_synced(page_id: int, synced_block_id: int,
                    block_index: int = 0) -> None:
    """Record that a page references a synced block at a given index."""
    with get_conn() as conn:
        conn.execute(
            """INSERT OR IGNORE INTO page_synced_blocks
               (page_id, synced_block_id, block_index)
               VALUES (?, ?, ?)""",
            (page_id, synced_block_id, block_index),
        )
        conn.commit()


def remove_page_synced(page_id: int, synced_block_id: int) -> None:
    """Remove a page's reference to a synced block."""
    with get_conn() as conn:
        conn.execute(
            "DELETE FROM page_synced_blocks WHERE page_id=? AND synced_block_id=?",
            (page_id, synced_block_id),
        )
        conn.commit()


def get_page_synced(page_id: int) -> list[dict]:
    """Get all synced block references for a page."""
    with get_conn() as conn:
        rows = conn.execute(
            """SELECT psb.*, sb.title, sb.content AS synced_content
               FROM page_synced_blocks psb
               JOIN synced_blocks sb ON sb.id=psb.synced_block_id
               WHERE psb.page_id=? ORDER BY psb.block_index""",
            (page_id,),
        ).fetchall()
    return [dict(r) for r in rows]


# ── Block resolution ──────────────────────────────────────────────

def resolve_synced_block(blocks: list[dict]) -> list[dict]:
    """Replace synced block references with actual content for rendering.

    A synced block in the block list looks like:
        {"type": "synced", "synced_id": 42, "content": "..."}
    This resolves it to the current content from the synced_blocks table.
    """
    for b in blocks:
        if b.get("type") == "synced" and b.get("synced_id"):
            sb = get_synced_block(b["synced_id"])
            if sb:
                try:
                    resolved = json.loads(sb["content"])
                    if isinstance(resolved, list):
                        b["_synced_content"] = resolved
                        b["_synced_title"] = sb.get("title", "")
                        b["_synced_id"] = sb["id"]
                        b["_synced_updated"] = sb.get("updated_at", "")
                except (json.JSONDecodeError, TypeError):
                    pass
        if isinstance(b.get("children"), list):
            resolve_synced_block(b["children"])
    return blocks


def sync_synced_blocks_in_page(page_id: int) -> None:
    """Re-resolve all synced blocks in a page's content.

    Called after a synced block is updated — refreshes the referencing
    pages' block content so they reflect the latest source.
    """
    refs = get_page_synced(page_id)
    if not refs:
        return
    with get_conn() as conn:
        row = conn.execute(
            "SELECT content, content_format FROM pages WHERE id=?",
            (page_id,),
        ).fetchone()
        if not row or row["content_format"] != "blocks":
            return
        try:
            blocks = json.loads(row["content"])
        except (json.JSONDecodeError, TypeError):
            return

    changed = False
    for ref in refs:
        sb = get_synced_block(ref["synced_block_id"])
        if sb:
            try:
                resolved = json.loads(sb["content"])
            except (json.JSONDecodeError, TypeError):
                continue
            for b in blocks:
                if b.get("type") == "synced" and b.get("synced_id") == ref["synced_block_id"]:
                    b["content"] = json.dumps(resolved, ensure_ascii=False) if isinstance(resolved, list) else json.dumps(resolved)
                    b["_synced_content"] = resolved
                    b["_synced_title"] = sb.get("title", "")
                    changed = True
                    break

    if changed:
        with get_conn() as conn:
            conn.execute(
                "UPDATE pages SET content=?, updated_at=CURRENT_TIMESTAMP WHERE id=?",
                (json.dumps(blocks, ensure_ascii=False), page_id),
            )
            conn.commit()


# ── Unsync: convert synced block to independent copy ──────────────

def unsync_block(page_id: int, synced_block_id: int) -> list[dict] | None:
    """Remove a page's sync reference and return the current content
    so the caller can turn it into an independent block."""
    sb = get_synced_block(synced_block_id)
    if not sb:
        return None
    remove_page_synced(page_id, synced_block_id)
    try:
        return json.loads(sb["content"])
    except (json.JSONDecodeError, TypeError):
        return None