"""BAN YARO — Ausgaben-Tracker Routes"""

import logging
from datetime import date, timedelta
from dateutil.relativedelta import relativedelta
from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from typing import Optional
from database import db
from auth import get_current_user

router = APIRouter()
logger = logging.getLogger(__name__)

KATEGORIEN = {"tierarzt", "futter", "zubehoer", "versicherung", "sitter", "sonstiges"}


# ------------------------------------------------------------------
# Schemas
# ------------------------------------------------------------------
class ExpenseCreate(BaseModel):
    dog_id:    Optional[int]  = None
    kategorie: str
    betrag:    float
    datum:     str
    notiz:     Optional[str]  = None


class ExpenseUpdate(BaseModel):
    dog_id:    Optional[int]   = None
    kategorie: Optional[str]   = None
    betrag:    Optional[float] = None
    datum:     Optional[str]   = None
    notiz:     Optional[str]   = None


class RecurringCreate(BaseModel):
    dog_id:      Optional[int]  = None
    kategorie:   str
    betrag:      float
    haeufigkeit: str            # monatlich | quartalsweise | jaehrlich
    startdatum:  str            # ISO date
    notiz:       Optional[str]  = None

class RecurringUpdate(BaseModel):
    dog_id:      Optional[int]   = None
    kategorie:   Optional[str]   = None
    betrag:      Optional[float] = None
    haeufigkeit: Optional[str]   = None
    startdatum:  Optional[str]   = None
    notiz:       Optional[str]   = None
    aktiv:       Optional[bool]  = None


HAEUFIGKEITEN = {"monatlich", "quartalsweise", "jaehrlich"}


def _next_due(startdatum: str, haeufigkeit: str, after: date) -> date:
    """Berechnet das nächste Fälligkeitsdatum nach `after`."""
    d = date.fromisoformat(startdatum)
    if d > after:
        return d
    if haeufigkeit == "monatlich":
        delta = relativedelta(months=1)
    elif haeufigkeit == "quartalsweise":
        delta = relativedelta(months=3)
    else:
        delta = relativedelta(years=1)
    while d <= after:
        d += delta
    return d


def _serialize(row) -> dict:
    return dict(row)


# ------------------------------------------------------------------
# GET /api/expenses/summary — Monats- und Jahressummen
# WICHTIG: Diese Route muss VOR /{id} stehen!
# ------------------------------------------------------------------
@router.get("/summary")
async def get_summary(
    dog_id: Optional[int] = Query(default=None),
    user=Depends(get_current_user),
):
    today = date.today()
    monat_prefix = today.strftime("%Y-%m")
    jahr_prefix  = today.strftime("%Y")

    extra_cond = ""
    extra_params: list = []
    if dog_id is not None:
        extra_cond = " AND dog_id=?"
        extra_params = [dog_id]

    with db() as conn:
        # Monats-Summen pro Kategorie
        rows_monat = conn.execute(
            f"""SELECT kategorie, COALESCE(SUM(betrag),0) AS summe
                FROM expenses
                WHERE user_id=? AND datum LIKE ?{extra_cond}
                GROUP BY kategorie""",
            [user["id"], f"{monat_prefix}%"] + extra_params,
        ).fetchall()

        # Jahres-Summen pro Kategorie
        rows_jahr = conn.execute(
            f"""SELECT kategorie, COALESCE(SUM(betrag),0) AS summe
                FROM expenses
                WHERE user_id=? AND datum LIKE ?{extra_cond}
                GROUP BY kategorie""",
            [user["id"], f"{jahr_prefix}%"] + extra_params,
        ).fetchall()

    monat = {r["kategorie"]: round(r["summe"], 2) for r in rows_monat}
    jahr  = {r["kategorie"]: round(r["summe"], 2) for r in rows_jahr}

    gesamt_monat = round(sum(monat.values()), 2)
    gesamt_jahr  = round(sum(jahr.values()), 2)

    return {
        "monat":        monat,
        "jahr":         jahr,
        "gesamt_monat": gesamt_monat,
        "gesamt_jahr":  gesamt_jahr,
    }


# ------------------------------------------------------------------
# GET /api/expenses — Liste mit optionalen Filtern
# ------------------------------------------------------------------
@router.get("")
async def list_expenses(
    dog_id:  Optional[int] = Query(default=None),
    von:     Optional[str] = Query(default=None),
    bis:     Optional[str] = Query(default=None),
    limit:   int           = Query(default=100, le=500),
    offset:  int           = Query(default=0),
    user=Depends(get_current_user),
):
    conditions = ["e.user_id=?"]
    params: list = [user["id"]]

    if dog_id is not None:
        conditions.append("e.dog_id=?")
        params.append(dog_id)
    if von:
        conditions.append("e.datum >= ?")
        params.append(von)
    if bis:
        conditions.append("e.datum <= ?")
        params.append(bis)

    where = " AND ".join(conditions)
    params += [limit, offset]

    with db() as conn:
        rows = conn.execute(
            f"""SELECT e.*, d.name AS dog_name
                FROM expenses e
                LEFT JOIN dogs d ON d.id = e.dog_id
                WHERE {where}
                ORDER BY e.datum DESC, e.id DESC
                LIMIT ? OFFSET ?""",
            params,
        ).fetchall()

    return [_serialize(r) for r in rows]


# ------------------------------------------------------------------
# POST /api/expenses — neuer Eintrag
# ------------------------------------------------------------------
@router.post("", status_code=201)
async def create_expense(data: ExpenseCreate, user=Depends(get_current_user)):
    if data.kategorie not in KATEGORIEN:
        raise HTTPException(400, f"Ungültige Kategorie: {data.kategorie}")
    if data.betrag <= 0:
        raise HTTPException(400, "Betrag muss größer als 0 sein.")

    with db() as conn:
        # dog_id prüfen — muss dem User gehören
        if data.dog_id is not None:
            dog = conn.execute(
                "SELECT id FROM dogs WHERE id=? AND user_id=?",
                (data.dog_id, user["id"]),
            ).fetchone()
            if not dog:
                raise HTTPException(404, "Hund nicht gefunden.")

        conn.execute(
            """INSERT INTO expenses (user_id, dog_id, kategorie, betrag, datum, notiz)
               VALUES (?, ?, ?, ?, ?, ?)""",
            (user["id"], data.dog_id, data.kategorie, data.betrag, data.datum, data.notiz),
        )
        row = conn.execute(
            "SELECT * FROM expenses WHERE user_id=? ORDER BY id DESC LIMIT 1",
            (user["id"],),
        ).fetchone()

    return _serialize(row)


# ------------------------------------------------------------------
# PATCH /api/expenses/{id} — bearbeiten
# ------------------------------------------------------------------
@router.patch("/{expense_id}")
async def update_expense(
    expense_id: int, data: ExpenseUpdate, user=Depends(get_current_user)
):
    with db() as conn:
        row = conn.execute(
            "SELECT * FROM expenses WHERE id=? AND user_id=?",
            (expense_id, user["id"]),
        ).fetchone()
        if not row:
            raise HTTPException(404, "Eintrag nicht gefunden.")

        updates = {}
        if data.kategorie is not None:
            if data.kategorie not in KATEGORIEN:
                raise HTTPException(400, f"Ungültige Kategorie: {data.kategorie}")
            updates["kategorie"] = data.kategorie
        if data.betrag is not None:
            if data.betrag <= 0:
                raise HTTPException(400, "Betrag muss größer als 0 sein.")
            updates["betrag"] = data.betrag
        if data.datum is not None:
            updates["datum"] = data.datum
        if data.notiz is not None:
            updates["notiz"] = data.notiz
        if data.dog_id is not None:
            dog = conn.execute(
                "SELECT id FROM dogs WHERE id=? AND user_id=?",
                (data.dog_id, user["id"]),
            ).fetchone()
            if not dog:
                raise HTTPException(404, "Hund nicht gefunden.")
            updates["dog_id"] = data.dog_id

        if not updates:
            return _serialize(row)

        set_clause = ", ".join(f"{k}=?" for k in updates)
        values = list(updates.values()) + [expense_id]
        conn.execute(f"UPDATE expenses SET {set_clause} WHERE id=?", values)
        row = conn.execute("SELECT * FROM expenses WHERE id=?", (expense_id,)).fetchone()

    return _serialize(row)


# ------------------------------------------------------------------
# DELETE /api/expenses/{id} — löschen
# ------------------------------------------------------------------
@router.delete("/{expense_id}", status_code=204)
async def delete_expense(expense_id: int, user=Depends(get_current_user)):
    with db() as conn:
        row = conn.execute(
            "SELECT id FROM expenses WHERE id=? AND user_id=?",
            (expense_id, user["id"]),
        ).fetchone()
        if not row:
            raise HTTPException(404, "Eintrag nicht gefunden.")
        conn.execute("DELETE FROM expenses WHERE id=?", (expense_id,))
    return None


# ------------------------------------------------------------------
# Wiederkehrende Ausgaben
# ------------------------------------------------------------------
@router.get("/recurring")
async def list_recurring(user=Depends(get_current_user)):
    with db() as conn:
        rows = conn.execute(
            """SELECT r.*, d.name AS dog_name
               FROM recurring_expenses r
               LEFT JOIN dogs d ON d.id = r.dog_id
               WHERE r.user_id=? ORDER BY r.startdatum DESC""",
            (user["id"],),
        ).fetchall()
    return [dict(r) for r in rows]


@router.post("/recurring", status_code=201)
async def create_recurring(data: RecurringCreate, user=Depends(get_current_user)):
    if data.kategorie not in KATEGORIEN:
        raise HTTPException(400, f"Ungültige Kategorie: {data.kategorie}")
    if data.haeufigkeit not in HAEUFIGKEITEN:
        raise HTTPException(400, f"Ungültige Häufigkeit: {data.haeufigkeit}")
    if data.betrag <= 0:
        raise HTTPException(400, "Betrag muss größer als 0 sein.")

    today = date.today()
    naechste = _next_due(data.startdatum, data.haeufigkeit, today - timedelta(days=1))

    with db() as conn:
        if data.dog_id:
            if not conn.execute("SELECT 1 FROM dogs WHERE id=? AND user_id=?",
                                (data.dog_id, user["id"])).fetchone():
                raise HTTPException(404, "Hund nicht gefunden.")
        conn.execute(
            """INSERT INTO recurring_expenses
               (user_id, dog_id, kategorie, betrag, haeufigkeit, startdatum, naechste_faelligkeit, notiz)
               VALUES (?,?,?,?,?,?,?,?)""",
            (user["id"], data.dog_id, data.kategorie, data.betrag,
             data.haeufigkeit, data.startdatum, str(naechste), data.notiz),
        )
        row = conn.execute(
            "SELECT * FROM recurring_expenses WHERE user_id=? ORDER BY id DESC LIMIT 1",
            (user["id"],),
        ).fetchone()
    return dict(row)


@router.patch("/recurring/{rid}")
async def update_recurring(rid: int, data: RecurringUpdate, user=Depends(get_current_user)):
    with db() as conn:
        row = conn.execute(
            "SELECT * FROM recurring_expenses WHERE id=? AND user_id=?", (rid, user["id"])
        ).fetchone()
        if not row:
            raise HTTPException(404, "Dauerauftrag nicht gefunden.")
        updates: dict = {}
        if data.kategorie is not None:
            if data.kategorie not in KATEGORIEN:
                raise HTTPException(400, f"Ungültige Kategorie.")
            updates["kategorie"] = data.kategorie
        if data.betrag is not None:
            updates["betrag"] = data.betrag
        if data.haeufigkeit is not None:
            if data.haeufigkeit not in HAEUFIGKEITEN:
                raise HTTPException(400, "Ungültige Häufigkeit.")
            updates["haeufigkeit"] = data.haeufigkeit
        if data.startdatum is not None:
            updates["startdatum"] = data.startdatum
        if data.notiz is not None:
            updates["notiz"] = data.notiz
        if data.aktiv is not None:
            updates["aktiv"] = 1 if data.aktiv else 0
        if updates:
            # naechste_faelligkeit neu berechnen wenn relevante Felder geändert
            startdatum   = updates.get("startdatum",   row["startdatum"])
            haeufigkeit  = updates.get("haeufigkeit",  row["haeufigkeit"])
            today        = date.today()
            updates["naechste_faelligkeit"] = str(
                _next_due(startdatum, haeufigkeit, today - timedelta(days=1))
            )
            set_clause = ", ".join(f"{k}=?" for k in updates)
            conn.execute(f"UPDATE recurring_expenses SET {set_clause} WHERE id=?",
                         [*updates.values(), rid])
        row = conn.execute("SELECT * FROM recurring_expenses WHERE id=?", (rid,)).fetchone()
    return dict(row)


@router.delete("/recurring/{rid}", status_code=204)
async def delete_recurring(rid: int, user=Depends(get_current_user)):
    with db() as conn:
        if not conn.execute("SELECT 1 FROM recurring_expenses WHERE id=? AND user_id=?",
                            (rid, user["id"])).fetchone():
            raise HTTPException(404, "Dauerauftrag nicht gefunden.")
        conn.execute("DELETE FROM recurring_expenses WHERE id=?", (rid,))
    return None


def process_due_recurring(user_id: int | None = None):
    """Legt fällige Daueraufträge als Einträge an. Wird vom Scheduler aufgerufen."""
    today = date.today()
    today_str = str(today)
    with db() as conn:
        where = "aktiv=1 AND naechste_faelligkeit <= ?"
        params: list = [today_str]
        if user_id:
            where += " AND user_id=?"
            params.append(user_id)
        rows = conn.execute(
            f"SELECT * FROM recurring_expenses WHERE {where}", params
        ).fetchall()

        for r in rows:
            # Eintrag anlegen
            conn.execute(
                """INSERT INTO expenses (user_id, dog_id, kategorie, betrag, datum, notiz)
                   VALUES (?,?,?,?,?,?)""",
                (r["user_id"], r["dog_id"], r["kategorie"], r["betrag"],
                 r["naechste_faelligkeit"],
                 f"[Dauerauftrag] {r['notiz'] or r['kategorie']}"),
            )
            # Nächste Fälligkeit berechnen
            naechste = _next_due(r["startdatum"], r["haeufigkeit"],
                                 date.fromisoformat(r["naechste_faelligkeit"]))
            conn.execute(
                "UPDATE recurring_expenses SET naechste_faelligkeit=? WHERE id=?",
                (str(naechste), r["id"]),
            )
    return len(rows) if rows else 0