from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, desc
from pydantic import BaseModel
from typing import Optional, List
from datetime import datetime, date, timezone

from app.core.database import get_db
from app.core.security import get_current_user, hash_password, verify_password
from app.models.user import User, WeightLog

router = APIRouter()


# ── Profile ────────────────────────────────────────────────────────────────

class ProfileUpdate(BaseModel):
    max_heart_rate: Optional[int] = None
    resting_heart_rate: Optional[int] = None
    birth_year: Optional[int] = None
    height_cm: Optional[float] = None
    biological_sex: Optional[str] = None


class ProfileOut(BaseModel):
    id: int
    username: str
    email: Optional[str]
    max_heart_rate: Optional[int]
    resting_heart_rate: Optional[int]
    birth_year: Optional[int]
    height_cm: Optional[float]
    biological_sex: Optional[str]
    estimated_max_hr: Optional[int]
    is_admin: bool

    class Config:
        from_attributes = True


def _estimated_max_hr(user: User) -> Optional[int]:
    if user.birth_year:
        return 220 - (datetime.now().year - user.birth_year)
    return None


@router.get("/", response_model=ProfileOut)
async def get_profile(current_user: User = Depends(get_current_user)):
    return {**{c.name: getattr(current_user, c.name)
               for c in User.__table__.columns},
            "estimated_max_hr": _estimated_max_hr(current_user)}


@router.patch("/", response_model=ProfileOut)
async def update_profile(
    body: ProfileUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    old_max_hr = current_user.max_heart_rate
    if body.max_heart_rate is not None:
        if not (100 <= body.max_heart_rate <= 250):
            raise HTTPException(400, "Max HR must be 100–250")
        current_user.max_heart_rate = body.max_heart_rate
    if body.resting_heart_rate is not None:
        if not (20 <= body.resting_heart_rate <= 120):
            raise HTTPException(400, "Resting HR must be 20–120")
        current_user.resting_heart_rate = body.resting_heart_rate
    if body.birth_year is not None:
        if not (1920 <= body.birth_year <= 2010):
            raise HTTPException(400, "Invalid birth year")
        current_user.birth_year = body.birth_year
    if body.height_cm is not None:
        if not (50 <= body.height_cm <= 300):
            raise HTTPException(400, "Height must be 50–300 cm")
        current_user.height_cm = body.height_cm
    if body.biological_sex is not None:
        if body.biological_sex not in ('male', 'female', ''):
            raise HTTPException(400, "biological_sex must be 'male' or 'female'")
        current_user.biological_sex = body.biological_sex or None

    await db.commit()
    await db.refresh(current_user)

    if body.max_heart_rate is not None and body.max_heart_rate != old_max_hr:
        from app.workers.tasks import recalculate_hr_zones_for_user
        recalculate_hr_zones_for_user.delay(current_user.id, body.max_heart_rate)

    return {**{c.name: getattr(current_user, c.name)
               for c in User.__table__.columns},
            "estimated_max_hr": _estimated_max_hr(current_user)}


# ── Password change ────────────────────────────────────────────────────────

class PasswordChange(BaseModel):
    current_password: str
    new_password: str


@router.post("/change-password")
async def change_password(
    body: PasswordChange,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    if not current_user.hashed_password:
        raise HTTPException(400, "Account uses passkey login — no password to change")
    if not verify_password(body.current_password, current_user.hashed_password):
        raise HTTPException(400, "Current password is incorrect")
    if len(body.new_password) < 8:
        raise HTTPException(400, "New password must be at least 8 characters")
    current_user.hashed_password = hash_password(body.new_password)
    await db.commit()
    return {"status": "ok"}


# ── PocketID configuration (admin only) ────────────────────────────────────

class PocketIDConfig(BaseModel):
    issuer: Optional[str] = None
    client_id: Optional[str] = None
    client_secret: Optional[str] = None
    allowed_group: Optional[str] = None


@router.get("/pocketid-config")
async def get_pocketid_config(current_user: User = Depends(get_current_user)):
    if not current_user.is_admin:
        raise HTTPException(403, "Admin only")
    from app.core.config import settings
    # Show DB config if set, fall back to env
    issuer = current_user.pocketid_issuer or settings.pocketid_issuer
    client_id = current_user.pocketid_client_id or settings.pocketid_client_id
    allowed_group = current_user.pocketid_allowed_group or settings.pocketid_allowed_group
    return {
        "issuer": issuer or "",
        "client_id": client_id or "",
        "client_secret_set": bool(current_user.pocketid_client_secret or settings.pocketid_client_secret),
        "allowed_group": allowed_group or "",
        "enabled": bool(issuer and client_id),
    }


@router.post("/pocketid-config")
async def save_pocketid_config(
    body: PocketIDConfig,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    if not current_user.is_admin:
        raise HTTPException(403, "Admin only")
    if body.issuer is not None:
        current_user.pocketid_issuer = body.issuer.rstrip("/") if body.issuer else None
    if body.client_id is not None:
        current_user.pocketid_client_id = body.client_id or None
    # Only overwrite the secret when a non-empty value is supplied; a blank
    # field means "keep the existing secret" (matches the UI hint).
    if body.client_secret:
        current_user.pocketid_client_secret = body.client_secret
    if body.allowed_group is not None:
        current_user.pocketid_allowed_group = body.allowed_group.strip() or None
    await db.commit()
    return {"status": "ok"}


# ── Weight log ─────────────────────────────────────────────────────────────

class WeightEntry(BaseModel):
    date: datetime
    weight_kg: float
    body_fat_pct: Optional[float] = None
    note: Optional[str] = None


class WeightOut(BaseModel):
    id: int
    date: datetime
    weight_kg: float
    body_fat_pct: Optional[float]
    note: Optional[str]

    class Config:
        from_attributes = True


@router.get("/weight", response_model=List[WeightOut])
async def list_weight(
    limit: int = 365,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(
        select(WeightLog)
        .where(WeightLog.user_id == current_user.id)
        .order_by(desc(WeightLog.date))
        .limit(limit)
    )
    return result.scalars().all()


@router.post("/weight", response_model=WeightOut)
async def log_weight(
    body: WeightEntry,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    if not (20 <= body.weight_kg <= 500):
        raise HTTPException(400, "Weight must be 20–500 kg")
    entry = WeightLog(
        user_id=current_user.id,
        date=body.date,
        weight_kg=body.weight_kg,
        body_fat_pct=body.body_fat_pct,
        note=body.note,
    )
    db.add(entry)
    await db.commit()
    await db.refresh(entry)
    return entry


@router.delete("/weight/{entry_id}", status_code=204)
async def delete_weight(
    entry_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(
        select(WeightLog).where(
            WeightLog.id == entry_id,
            WeightLog.user_id == current_user.id,
        )
    )
    entry = result.scalar_one_or_none()
    if not entry:
        raise HTTPException(404, "Not found")
    await db.delete(entry)
    await db.commit()