import json
import uuid
from datetime import datetime, timedelta, timezone, date as date_type
from decimal import Decimal

from mcp.server.fastmcp import FastMCP
from sqlalchemy import select, and_, text, or_
from sqlalchemy.orm import selectinload

from app.core.database import AsyncSessionLocal
from app.models.todos import TodoItem
from app.models.notes import NoteItem
from app.models.shopping import ShoppingList, ListItem, Product

_VALID_STATUSES = {"pending", "done", "cancelled"}
_VALID_PRIORITIES = {"low", "medium", "high"}

mcp = FastMCP("HomeHub", stateless_http=True)


def _serialize(obj):
    if isinstance(obj, uuid.UUID):
        return str(obj)
    if isinstance(obj, datetime):
        return obj.isoformat()
    if isinstance(obj, date_type):
        return obj.isoformat()
    if isinstance(obj, Decimal):
        return float(obj)
    raise TypeError(f"Type non sérialisable : {type(obj)}")


def _dumps(data) -> str:
    return json.dumps(data, default=_serialize)


def _iso_week_label() -> str:
    now = datetime.now(tz=timezone.utc)
    iso = now.isocalendar()
    return f"S{iso[1]} {iso[0]}"


# ── TODOS ──────────────────────────────────────────────────────────────────────

@mcp.tool()
async def get_todos(
    status: str = "pending",
    domain: str | None = None,
    priority: str | None = None,
) -> str:
    """Liste filtrée des tâches. status: pending/done/cancelled. priority: low/medium/high."""
    async with AsyncSessionLocal() as session:
        conditions = [TodoItem.status == status]
        if domain:
            conditions.append(TodoItem.domains.contains([domain]))
        if priority:
            conditions.append(TodoItem.priority == priority)
        stmt = (
            select(TodoItem)
            .where(and_(*conditions))
            .order_by(TodoItem.due_date.asc().nulls_last(), TodoItem.created_at.desc())
            .limit(100)
        )
        result = await session.execute(stmt)
        items = result.scalars().all()
        return _dumps([{
            "id": item.id,
            "title": item.title,
            "status": item.status,
            "priority": item.priority,
            "domains": item.domains,
            "tags": item.tags,
            "due_date": item.due_date,
            "postponed_count": item.postponed_count,
        } for item in items])


@mcp.tool()
async def create_todo(
    title: str,
    due_date: str | None = None,
    priority: str | None = None,
    domain: str | None = None,
) -> str:
    """Crée une tâche. due_date en ISO 8601 (ex: 2025-06-01T10:00:00Z). priority: low/medium/high."""
    if priority and priority not in _VALID_PRIORITIES:
        return _dumps({"error": f"Priorité invalide : {priority}. Valeurs: low/medium/high"})
    async with AsyncSessionLocal() as session:
        parsed_due = None
        if due_date:
            try:
                parsed_due = datetime.fromisoformat(due_date.replace("Z", "+00:00"))
            except ValueError:
                return _dumps({"error": f"Format de date invalide : {due_date}"})
        item = TodoItem(
            title=title,
            due_date=parsed_due,
            priority=priority or "medium",
            domains=[domain] if domain else [],
        )
        session.add(item)
        await session.commit()
        await session.refresh(item)
        return _dumps({
            "id": item.id,
            "title": item.title,
            "status": item.status,
            "priority": item.priority,
            "domains": item.domains,
            "due_date": item.due_date,
        })


@mcp.tool()
async def update_todo(
    id: str,
    title: str | None = None,
    status: str | None = None,
    priority: str | None = None,
) -> str:
    """Modifie une tâche. status: pending/done/cancelled. priority: low/medium/high."""
    async with AsyncSessionLocal() as session:
        try:
            todo_id = uuid.UUID(id)
        except ValueError:
            return _dumps({"error": f"UUID invalide : {id}"})
        item = await session.get(TodoItem, todo_id)
        if not item:
            return _dumps({"error": f"Tâche introuvable : {id}"})
        if status is not None and status not in _VALID_STATUSES:
            return _dumps({"error": f"Statut invalide : {status}. Valeurs: pending/done/cancelled"})
        if priority is not None and priority not in _VALID_PRIORITIES:
            return _dumps({"error": f"Priorité invalide : {priority}. Valeurs: low/medium/high"})
        if title is not None:
            item.title = title
        if status is not None:
            item.status = status
        if priority is not None:
            item.priority = priority
        item.updated_at = datetime.now(timezone.utc)
        await session.commit()
        await session.refresh(item)
        return _dumps({
            "id": item.id,
            "title": item.title,
            "status": item.status,
            "priority": item.priority,
        })


@mcp.tool()
async def postpone_todo(id: str, days: int) -> str:
    """Reporte une tâche de N jours à partir de sa date d'échéance (ou maintenant si nulle)."""
    async with AsyncSessionLocal() as session:
        try:
            todo_id = uuid.UUID(id)
        except ValueError:
            return _dumps({"error": f"UUID invalide : {id}"})
        item = await session.get(TodoItem, todo_id)
        if not item:
            return _dumps({"error": f"Tâche introuvable : {id}"})
        now = datetime.now(timezone.utc)
        base = item.due_date if item.due_date else now
        item.due_date = base + timedelta(days=days)
        item.postponed_count += 1
        item.updated_at = now
        await session.commit()
        await session.refresh(item)
        return _dumps({
            "id": item.id,
            "title": item.title,
            "due_date": item.due_date,
            "postponed_count": item.postponed_count,
        })


@mcp.tool()
async def delete_todo(id: str) -> str:
    """Supprime une tâche définitivement."""
    async with AsyncSessionLocal() as session:
        try:
            todo_id = uuid.UUID(id)
        except ValueError:
            return _dumps({"error": f"UUID invalide : {id}"})
        item = await session.get(TodoItem, todo_id)
        if not item:
            return _dumps({"error": f"Tâche introuvable : {id}"})
        await session.delete(item)
        await session.commit()
        return _dumps({"deleted": id})


# ── NOTES ──────────────────────────────────────────────────────────────────────

@mcp.tool()
async def search_notes(
    query: str | None = None,
    category: str | None = None,
    tag: str | None = None,
) -> str:
    """Recherche de notes via FTS PostgreSQL (français). query cherche dans titre+contenu."""
    async with AsyncSessionLocal() as session:
        conditions = []
        if category:
            conditions.append(NoteItem.category == category)
        if tag:
            conditions.append(NoteItem.tags.contains([tag]))
        if query:
            conditions.append(
                text(
                    "to_tsvector('french', coalesce(title,'') || ' ' || content)"
                    " @@ plainto_tsquery('french', :q)"
                ).bindparams(q=query)
            )
        stmt = (
            select(NoteItem)
            .options(selectinload(NoteItem.attachments))
            .order_by(NoteItem.created_at.desc())
            .limit(20)
        )
        if conditions:
            stmt = stmt.where(and_(*conditions))
        result = await session.execute(stmt)
        notes = result.scalars().all()
        return _dumps([{
            "id": n.id,
            "title": n.title,
            "category": n.category,
            "tags": n.tags,
            "content_preview": n.content[:200] if n.content else "",
            "created_at": n.created_at,
            "attachment_count": len(n.attachments),
        } for n in notes])


@mcp.tool()
async def get_note(id: str) -> str:
    """Retourne une note complète avec ses pièces jointes."""
    async with AsyncSessionLocal() as session:
        try:
            note_id = uuid.UUID(id)
        except ValueError:
            return _dumps({"error": f"UUID invalide : {id}"})
        stmt = (
            select(NoteItem)
            .where(NoteItem.id == note_id)
            .options(selectinload(NoteItem.attachments))
        )
        result = await session.execute(stmt)
        note = result.scalar_one_or_none()
        if not note:
            return _dumps({"error": f"Note introuvable : {id}"})
        return _dumps({
            "id": note.id,
            "title": note.title,
            "content": note.content,
            "category": note.category,
            "tags": note.tags,
            "created_at": note.created_at,
            "attachments": [{
                "id": a.id,
                "file_type": a.file_type,
                "original_name": a.original_name,
            } for a in note.attachments],
        })


@mcp.tool()
async def create_note(
    title: str,
    content: str,
    category: str | None = None,
    tags: list[str] | None = None,
) -> str:
    """Crée une note avec titre, contenu markdown, catégorie optionnelle et tags."""
    async with AsyncSessionLocal() as session:
        note = NoteItem(
            title=title,
            content=content,
            category=category,
            tags=tags or [],
        )
        session.add(note)
        await session.commit()
        await session.refresh(note)
        return _dumps({
            "id": note.id,
            "title": note.title,
            "category": note.category,
            "tags": note.tags,
            "created_at": note.created_at,
        })


@mcp.tool()
async def update_note(
    id: str,
    title: str | None = None,
    content: str | None = None,
    tags: list[str] | None = None,
) -> str:
    """Modifie le titre, le contenu ou les tags d'une note."""
    async with AsyncSessionLocal() as session:
        try:
            note_id = uuid.UUID(id)
        except ValueError:
            return _dumps({"error": f"UUID invalide : {id}"})
        note = await session.get(NoteItem, note_id)
        if not note:
            return _dumps({"error": f"Note introuvable : {id}"})
        if title is not None:
            note.title = title
        if content is not None:
            note.content = content
        if tags is not None:
            note.tags = tags
        await session.commit()
        await session.refresh(note)
        return _dumps({"id": note.id, "title": note.title, "tags": note.tags})


@mcp.tool()
async def delete_note(id: str) -> str:
    """Supprime une note et toutes ses pièces jointes (cascade)."""
    async with AsyncSessionLocal() as session:
        try:
            note_id = uuid.UUID(id)
        except ValueError:
            return _dumps({"error": f"UUID invalide : {id}"})
        note = await session.get(NoteItem, note_id)
        if not note:
            return _dumps({"error": f"Note introuvable : {id}"})
        await session.delete(note)
        await session.commit()
        return _dumps({"deleted": id})


# ── SHOPPING ────────────────────────────────────────────────────────────────────

@mcp.tool()
async def get_shopping_lists() -> str:
    """Retourne toutes les listes de courses avec compteurs d'articles cochés/total."""
    async with AsyncSessionLocal() as session:
        stmt = (
            select(ShoppingList)
            .options(selectinload(ShoppingList.items))
            .order_by(ShoppingList.created_at.desc())
        )
        result = await session.execute(stmt)
        lists = result.scalars().all()
        return _dumps([{
            "id": lst.id,
            "name": lst.name,
            "status": lst.status,
            "week_date": lst.week_date,
            "created_at": lst.created_at,
            "item_count": len(lst.items),
            "checked_count": sum(1 for i in lst.items if i.is_checked),
        } for lst in lists])


@mcp.tool()
async def get_active_shopping_list() -> str:
    """Retourne la première liste en statut 'draft' ou 'active' avec tous ses articles triés."""
    async with AsyncSessionLocal() as session:
        stmt = (
            select(ShoppingList)
            .where(ShoppingList.status.in_(["draft", "active"]))
            .options(selectinload(ShoppingList.items).selectinload(ListItem.product))
            .order_by(ShoppingList.status.asc(), ShoppingList.created_at.desc())
            .limit(1)
        )
        result = await session.execute(stmt)
        lst = result.scalar_one_or_none()
        if not lst:
            return _dumps({"error": "Aucune liste active (statut draft ou active)"})
        sorted_items = sorted(lst.items, key=lambda i: (i.sort_order or 999, str(i.id)))
        return _dumps({
            "id": lst.id,
            "name": lst.name,
            "status": lst.status,
            "item_count": len(lst.items),
            "checked_count": sum(1 for i in lst.items if i.is_checked),
            "items": [{
                "id": item.id,
                "name": item.custom_name or (item.product.name if item.product else "Article inconnu"),
                "quantity": item.quantity,
                "unit": item.unit,
                "is_checked": item.is_checked,
            } for item in sorted_items],
        })


@mcp.tool()
async def search_products(q: str) -> str:
    """Recherche dans le catalogue produits par nom, description ou catégorie."""
    if not q or not q.strip():
        return _dumps({"error": "Paramètre q requis"})
    async with AsyncSessionLocal() as session:
        stmt = (
            select(Product)
            .where(
                or_(
                    Product.name.ilike(f"%{q}%"),
                    Product.description.ilike(f"%{q}%"),
                    Product.category.ilike(f"%{q}%"),
                )
            )
            .order_by(Product.frequency_score.desc())
            .limit(20)
        )
        result = await session.execute(stmt)
        products = result.scalars().all()
        return _dumps([{
            "id": p.id,
            "name": p.name,
            "brand": p.brand,
            "category": p.category,
            "default_unit": p.default_unit,
            "frequency_score": p.frequency_score,
            "last_purchased_at": p.last_purchased_at,
        } for p in products])


@mcp.tool()
async def create_shopping_list(name: str | None = None) -> str:
    """Crée une liste de courses. name auto = semaine ISO courante si absent (ex: 'S22 2026')."""
    async with AsyncSessionLocal() as session:
        lst = ShoppingList(name=name or _iso_week_label())
        session.add(lst)
        await session.commit()
        await session.refresh(lst)
        return _dumps({
            "id": lst.id,
            "name": lst.name,
            "status": lst.status,
            "created_at": lst.created_at,
        })


@mcp.tool()
async def add_shopping_item(
    list_id: str,
    name: str,
    quantity: float | None = 1.0,
    unit: str | None = None,
) -> str:
    """Ajoute un article à une liste de courses."""
    async with AsyncSessionLocal() as session:
        try:
            lid = uuid.UUID(list_id)
        except ValueError:
            return _dumps({"error": f"UUID de liste invalide : {list_id}"})
        lst = await session.get(ShoppingList, lid)
        if not lst:
            return _dumps({"error": f"Liste introuvable : {list_id}"})
        item = ListItem(
            list_id=lid,
            custom_name=name,
            quantity=Decimal(str(quantity)) if quantity is not None else None,
            unit=unit,
        )
        session.add(item)
        await session.commit()
        await session.refresh(item)
        return _dumps({
            "id": item.id,
            "name": item.custom_name,
            "quantity": item.quantity,
            "unit": item.unit,
            "is_checked": item.is_checked,
        })


@mcp.tool()
async def check_shopping_item(list_id: str, item_id: str) -> str:
    """Coche un article (marque comme acheté). Met à jour les stats du produit lié si présent."""
    async with AsyncSessionLocal() as session:
        try:
            lid = uuid.UUID(list_id)
            iid = uuid.UUID(item_id)
        except ValueError:
            return _dumps({"error": "UUID invalide (list_id ou item_id)"})
        stmt = (
            select(ListItem)
            .where(ListItem.id == iid, ListItem.list_id == lid)
            .options(selectinload(ListItem.product))
        )
        result = await session.execute(stmt)
        item = result.scalar_one_or_none()
        if not item:
            return _dumps({"error": f"Article introuvable : {item_id} dans liste {list_id}"})
        was_checked = item.is_checked
        item.is_checked = True
        if not was_checked and item.product:
            product = item.product
            today = date_type.today()
            if product.last_purchased_at and product.last_purchased_at < today:
                days = (today - product.last_purchased_at).days
                if product.avg_interval_days is None:
                    product.avg_interval_days = Decimal(str(days))
                else:
                    product.avg_interval_days = Decimal(str(
                        round(float(product.avg_interval_days) * 0.7 + days * 0.3, 1)
                    ))
            product.last_purchased_at = today
            product.frequency_score += 1
        await session.commit()
        return _dumps({"id": item.id, "is_checked": item.is_checked})