"""API v1: эндпоинты публикации, конвертации, управления аккаунтами."""

from __future__ import annotations

import json
from datetime import datetime

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import select, func
from sqlalchemy.ext.asyncio import AsyncSession

from app.database import get_db
from app.models import User, VkAccount, Publication
from app.security import decrypt_token, encrypt_token
from app.vk_client import VkClient, VkApiError
from app.converters.markdown_to_vk import markdown_to_vk, format_data_json
from app.api.schemas import (
    AccountCreateRequest,
    AccountResponse,
    AccountListResponse,
    PublishRequest,
    PublishResponse,
    ConvertRequest,
    ConvertResponse,
    PublicationFilterRequest,
    PublicationItem,
    PublicationListResponse,
)
from app.api.deps import get_current_user_from_header, get_user_by_api_key

router = APIRouter(prefix="/api/v1", tags=["v1"])


# ─── Health ─────────────────────────────────────────────────────────────────


@router.get("/health")
async def health():
    return {"status": "ok"}


# ─── Аккаунты ──────────────────────────────────────────────────────────────


@router.post("/accounts", response_model=AccountResponse)
async def create_account(
    req: AccountCreateRequest,
    db: AsyncSession = Depends(get_db),
):
    """Добавить VK-аккаунт. Проверяет токен через VK API перед сохранением."""
    user = await get_user_by_api_key(req.api_key, db)

    # Проверяем токен через VK API
    vk = VkClient(req.access_token)
    try:
        is_valid, display_name = await vk.check_token()
        if not is_valid:
            raise HTTPException(status_code=400, detail=f"VK token invalid: {display_name}")
    except VkApiError as e:
        raise HTTPException(status_code=400, detail=f"VK API error: {e}")
    finally:
        await vk.close()

    # Шифруем токен перед сохранением
    encrypted = encrypt_token(req.access_token)
    name = req.display_name or display_name or f"VK-{req.vk_user_id}"

    # Проверяем, нет ли уже такого VK-аккаунта у пользователя
    existing = await db.execute(
        select(VkAccount).where(
            VkAccount.user_id == user.id,
            VkAccount.vk_user_id == req.vk_user_id,
            VkAccount.is_active == True,
        )
    )
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=409, detail="This VK account is already registered")

    account = VkAccount(
        user_id=user.id,
        vk_user_id=req.vk_user_id,
        display_name=name,
        access_token_enc=encrypted,
        token_type=req.token_type,
    )
    db.add(account)
    await db.flush()
    await db.refresh(account)

    return AccountResponse(
        id=account.id,
        vk_user_id=account.vk_user_id,
        display_name=account.display_name,
        token_type=account.token_type,
        is_active=account.is_active,
        created_at=account.created_at,
    )


@router.get("/accounts", response_model=AccountListResponse)
async def list_accounts(
    user: User = Depends(get_current_user_from_header),
    db: AsyncSession = Depends(get_db),
):
    """Список VK-аккаунтов текущего пользователя."""
    result = await db.execute(
        select(VkAccount).where(VkAccount.user_id == user.id, VkAccount.is_active == True)
    )
    accounts = result.scalars().all()

    return AccountListResponse(
        accounts=[
            AccountResponse(
                id=a.id,
                vk_user_id=a.vk_user_id,
                display_name=a.display_name,
                token_type=a.token_type,
                is_active=a.is_active,
                created_at=a.created_at,
            )
            for a in accounts
        ]
    )


@router.delete("/accounts/{account_id}", status_code=204)
async def delete_account(
    account_id: int,
    user: User = Depends(get_current_user_from_header),
    db: AsyncSession = Depends(get_db),
):
    """Удалить VK-аккаунт (soft delete)."""
    result = await db.execute(
        select(VkAccount).where(
            VkAccount.id == account_id,
            VkAccount.user_id == user.id,
        )
    )
    account = result.scalar_one_or_none()
    if account is None:
        raise HTTPException(status_code=404, detail="Account not found")

    account.is_active = False
    await db.flush()


# ─── Публикация ────────────────────────────────────────────────────────────


@router.post("/publish", response_model=PublishResponse)
async def publish(
    req: PublishRequest,
    db: AsyncSession = Depends(get_db),
):
    """Опубликовать пост на стене VK."""
    # Аутентификация по api_key из тела запроса
    user = await get_user_by_api_key(req.api_key, db)

    # Получаем VK-аккаунт
    result = await db.execute(
        select(VkAccount).where(
            VkAccount.id == req.vk_account_id,
            VkAccount.user_id == user.id,
            VkAccount.is_active == True,
        )
    )
    account = result.scalar_one_or_none()
    if account is None:
        raise HTTPException(status_code=404, detail="VK account not found")

    # Расшифровываем токен (только в памяти!)
    token = decrypt_token(account.access_token_enc)
    if token is None:
        raise HTTPException(status_code=500, detail="Failed to decrypt VK token (key mismatch?)")

    # Конвертируем Markdown
    chunks = markdown_to_vk(req.message_md)
    if not chunks or not chunks[0].text.strip():
        raise HTTPException(status_code=400, detail="Empty message after markdown conversion")

    chunk = chunks[0]
    fd_json = format_data_json(chunk.items) if chunk.items else None

    # Создаём запись о публикации
    publication = Publication(
        vk_account_id=account.id,
        status="draft",
        markdown_original=req.message_md,
        vk_text=chunk.text,
        vk_format_data=fd_json,
        scheduled_at=req.publish_date,
    )
    db.add(publication)
    await db.flush()

    # Если отложенная — сохраняем и выходим
    if req.publish_date:
        publication.status = "scheduled"
        await db.flush()
        return PublishResponse(
            success=True,
            publication_id=publication.id,
        )

    # Публикуем через VK API
    vk = VkClient(token)
    try:
        result = await vk.wall_post(
            message=chunk.text,
            owner_id=account.vk_user_id if account.token_type == "group" else None,
            from_group=(account.token_type == "group"),
            friends_only=req.friends_only,
            publish_date=int(req.publish_date.timestamp()) if req.publish_date else None,
            attachments=req.attachments,
            signed=req.signed,
            format_data=chunk.items if chunk.items else None,
        )

        post_id = result.get("post_id")
        owner_id = result.get("owner_id") or account.vk_user_id

        publication.status = "published"
        publication.vk_post_id = post_id
        publication.vk_owner_id = owner_id
        publication.published_at = datetime.utcnow()
        await db.flush()

        url = f"https://vk.com/wall{owner_id}_{post_id}"

        return PublishResponse(
            success=True,
            publication_id=publication.id,
            vk_post_id=post_id,
            vk_owner_id=owner_id,
            url=url,
        )

    except VkApiError as e:
        publication.status = "error"
        publication.error_message = str(e)
        await db.flush()
        return PublishResponse(
            success=False,
            publication_id=publication.id,
            error=str(e),
        )
    finally:
        await vk.close()


@router.post("/convert", response_model=ConvertResponse)
async def convert(req: ConvertRequest):
    """Конвертировать Markdown в VK format_data (без публикации)."""
    chunks = markdown_to_vk(req.message_md)
    if not chunks:
        return ConvertResponse(text="", format_data={"version": 1, "items": []})

    chunk = chunks[0]
    items = []
    for i in chunk.items:
        items.append({"type": i.type, "offset": i.offset, "length": i.length, "url": i.url})

    return ConvertResponse(
        text=chunk.text,
        format_data={"version": 1, "items": items},
    )


# ─── Архив публикаций ──────────────────────────────────────────────────────


@router.post("/publications", response_model=PublicationListResponse)
async def list_publications(
    req: PublicationFilterRequest,
    db: AsyncSession = Depends(get_db),
):
    """Архив публикаций с фильтрацией."""
    user = await get_user_by_api_key(req.api_key, db)

    # Базовый запрос — только публикации пользователя
    base_filter = VkAccount.user_id == user.id

    query = (
        select(Publication)
        .join(VkAccount)
        .where(base_filter)
    )
    count_query = (
        select(func.count(Publication.id))
        .join(VkAccount)
        .where(base_filter)
    )

    if req.vk_account_id is not None:
        query = query.where(Publication.vk_account_id == req.vk_account_id)
        count_query = count_query.where(Publication.vk_account_id == req.vk_account_id)
    if req.status is not None:
        query = query.where(Publication.status == req.status)
        count_query = count_query.where(Publication.status == req.status)

    total_result = await db.execute(count_query)
    total = total_result.scalar() or 0

    query = query.order_by(Publication.created_at.desc()).offset(req.offset).limit(req.limit)
    result = await db.execute(query)
    publications = result.scalars().all()

    return PublicationListResponse(
        publications=[
            PublicationItem(
                id=p.id,
                vk_account_id=p.vk_account_id,
                status=p.status,
                markdown_original=p.markdown_original,
                vk_post_id=p.vk_post_id,
                vk_owner_id=p.vk_owner_id,
                scheduled_at=p.scheduled_at,
                published_at=p.published_at,
                error_message=p.error_message,
                created_at=p.created_at,
            )
            for p in publications
        ],
        total=total,
    )