import json
from datetime import date, datetime, time, timedelta, timezone
from typing import Any

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.db.models import (
    BodyMetric,
    FitnessProfile,
    FitnessReminder,
    FoodLog,
    StepLog,
    WaterLog,
    WorkoutLog,
)
from app.fitness.activity_budget import (
    build_base_targets,
    compute_activity_bonus,
    estimate_workout_active_kcal,
    scale_targets,
)
from app.fitness.calculators import compute_targets, one_rep_max
from app.fitness.body_composition import compute_body_composition

DEFAULT_REMINDERS = [
    {"kind": "water", "hour": 9, "minute": 0, "interval_hours": 2},
    {"kind": "meal", "hour": 13, "minute": 0, "interval_hours": None},
    {"kind": "workout", "hour": 18, "minute": 0, "interval_hours": None},
    {"kind": "weigh_in", "hour": 8, "minute": 0, "interval_hours": None},
]


class FitnessService:
    def __init__(self, db: Session, user_id: int):
        self.db = db
        self.user_id = user_id

    def _get_profile_row(self) -> FitnessProfile | None:
        return self.db.scalar(select(FitnessProfile).where(FitnessProfile.user_id == self.user_id).limit(1))

    def get_profile(self) -> dict[str, Any] | None:
        row = self._get_profile_row()
        if not row:
            return None
        return self._profile_to_dict(row)

    def _profile_to_dict(self, row: FitnessProfile) -> dict[str, Any]:
        targets = compute_targets(
            {
                "sex": row.sex,
                "age": row.age,
                "height_cm": row.height_cm,
                "weight_kg": row.weight_kg,
                "activity_level": row.activity_level,
                "goal": row.goal,
            }
        )
        return {
            "sex": row.sex,
            "age": row.age,
            "height_cm": row.height_cm,
            "weight_kg": row.weight_kg,
            "activity_level": row.activity_level,
            "goal": row.goal,
            "target_weight_kg": row.target_weight_kg,
            "weekly_workouts": row.weekly_workouts,
            "baseline_steps": row.baseline_steps,
            "baseline_workout_kcal": row.baseline_workout_kcal,
            "calorie_target": row.calorie_target,
            "protein_g": row.protein_g,
            "fat_g": row.fat_g,
            "carbs_g": row.carbs_g,
            "water_l": row.water_l,
            "computed": targets,
            "updated_at": row.updated_at.isoformat() if row.updated_at else None,
        }

    def set_profile(self, updates: dict[str, Any]) -> dict[str, Any]:
        row = self._get_profile_row()
        is_new = row is None
        if is_new:
            row = FitnessProfile(user_id=self.user_id)
            self.db.add(row)
            self.db.flush()

        for key in (
            "sex", "age", "height_cm", "weight_kg", "activity_level",
            "goal", "target_weight_kg", "weekly_workouts",
            "baseline_steps", "baseline_workout_kcal",
        ):
            if key in updates and updates[key] is not None:
                setattr(row, key, updates[key])

        targets = compute_targets(
            {
                "sex": row.sex,
                "age": row.age,
                "height_cm": row.height_cm,
                "weight_kg": row.weight_kg,
                "activity_level": row.activity_level,
                "goal": row.goal,
            }
        )
        row.calorie_target = targets["calorie_target"]
        row.protein_g = targets["protein_g"]
        row.fat_g = targets["fat_g"]
        row.carbs_g = targets["carbs_g"]
        row.water_l = targets["water_l"]
        row.updated_at = datetime.now(timezone.utc)

        if is_new:
            self._ensure_default_reminders()

        self.db.commit()
        self.db.refresh(row)
        return {"ok": True, "profile": self._profile_to_dict(row)}

    def _ensure_default_reminders(self) -> None:
        existing = self.db.scalars(select(FitnessReminder).where(FitnessReminder.user_id == self.user_id)).all()
        if existing:
            return
        for item in DEFAULT_REMINDERS:
            self.db.add(FitnessReminder(user_id=self.user_id, **item))

    def calc_targets(self, params: dict[str, Any]) -> dict[str, Any]:
        return compute_targets(params)

    def calc_body_composition(self, params: dict[str, Any]) -> dict[str, Any]:
        profile = self.get_profile() or {}
        sex = params.get("sex") or profile.get("sex") or "male"
        height_cm = float(params.get("height_cm") or profile.get("height_cm") or 170)
        weight_kg = float(params.get("weight_kg") or profile.get("weight_kg") or 70)
        return compute_body_composition(
            sex=str(sex),
            height_cm=height_cm,
            weight_kg=weight_kg,
            neck_cm=params.get("neck_cm"),
            waist_cm=params.get("waist_cm"),
            hip_cm=params.get("hip_cm"),
            body_fat_pct=params.get("body_fat_pct"),
        )

    def get_latest_body_composition(self) -> dict[str, Any] | None:
        rows = self.list_body_metrics(limit=1)
        return rows[0] if rows else None

    @staticmethod
    def _body_metric_to_dict(row: BodyMetric) -> dict[str, Any]:
        return {
            "id": row.id,
            "weight_kg": row.weight_kg,
            "body_fat_pct": row.body_fat_pct,
            "body_fat_method": row.body_fat_method,
            "chest_cm": row.chest_cm,
            "waist_cm": row.waist_cm,
            "neck_cm": row.neck_cm,
            "hip_cm": row.hip_cm,
            "whr": row.whr,
            "lbm_kg": row.lbm_kg,
            "ffmi": row.ffmi,
            "notes": row.notes,
            "recorded_at": row.recorded_at.isoformat() if row.recorded_at else None,
        }

    @staticmethod
    def _resolve_logged_at(
        *,
        logged_at: datetime | str | None = None,
        day: date | None = None,
        days_ago: int | None = None,
    ) -> datetime:
        if logged_at is not None:
            if isinstance(logged_at, str):
                dt = datetime.fromisoformat(logged_at.replace("Z", "+00:00"))
                if dt.tzinfo is None:
                    dt = dt.replace(tzinfo=timezone.utc)
                return dt
            if logged_at.tzinfo is None:
                return logged_at.replace(tzinfo=timezone.utc)
            return logged_at

        target_day = day
        if target_day is None and days_ago is not None:
            target_day = datetime.now(timezone.utc).date() - timedelta(days=int(days_ago))

        if target_day is None:
            return datetime.now(timezone.utc)

        return datetime.combine(target_day, time(12, 0), tzinfo=timezone.utc)

    def _profile_for_budget(self, profile: dict[str, Any] | None) -> dict[str, Any]:
        if profile:
            return profile
        return {
            "calorie_target": 2000,
            "protein_g": 140,
            "fat_g": 65,
            "carbs_g": 200,
            "water_l": 2.5,
            "weight_kg": 70,
            "activity_level": "moderate",
            "weekly_workouts": 3,
        }


    def _day_bounds(self, day: date | None = None) -> tuple[datetime, datetime]:
        d = day or datetime.now(timezone.utc).date()
        start = datetime.combine(d, time.min, tzinfo=timezone.utc)
        end = datetime.combine(d, time.max, tzinfo=timezone.utc)
        return start, end

    def get_daily_summary(self, day: date | None = None) -> dict[str, Any]:
        start, end = self._day_bounds(day)
        profile_row = self.get_profile()
        profile = self._profile_for_budget(profile_row)

        foods = self.db.scalars(
            select(FoodLog)
            .where(FoodLog.user_id == self.user_id, FoodLog.logged_at >= start, FoodLog.logged_at <= end)
            .order_by(FoodLog.logged_at)
        ).all()
        waters = self.db.scalars(
            select(WaterLog)
            .where(WaterLog.user_id == self.user_id, WaterLog.logged_at >= start, WaterLog.logged_at <= end)
            .order_by(WaterLog.logged_at)
        ).all()
        workouts_rows = self.db.scalars(
            select(WorkoutLog)
            .where(WorkoutLog.user_id == self.user_id, WorkoutLog.logged_at >= start, WorkoutLog.logged_at <= end)
            .order_by(WorkoutLog.logged_at)
        ).all()
        steps_rows = self.db.scalars(
            select(StepLog)
            .where(StepLog.user_id == self.user_id, StepLog.logged_at >= start, StepLog.logged_at <= end)
            .order_by(StepLog.logged_at)
        ).all()

        workouts = [self._workout_to_dict(w) for w in workouts_rows]
        steps_total = sum(s.steps for s in steps_rows)

        totals = {
            "calories": sum(f.calories for f in foods),
            "protein_g": sum(f.protein_g for f in foods),
            "fat_g": sum(f.fat_g for f in foods),
            "carbs_g": sum(f.carbs_g for f in foods),
            "water_ml": sum(w.amount_ml for w in waters),
            "steps": steps_total,
        }

        base_targets = build_base_targets(profile)
        activity = compute_activity_bonus(
            profile,
            steps_total=steps_total,
            workouts=workouts,
        )
        effective_targets, targets_base = scale_targets(
            base_targets,
            activity.total_bonus_kcal,
        )

        return {
            "date": (day or datetime.now(timezone.utc).date()).isoformat(),
            "profile_configured": profile_row is not None,
            "totals": totals,
            "targets": effective_targets,
            "targets_base": targets_base,
            "activity": activity.to_dict(),
            "meals": [self._food_to_dict(f) for f in foods],
            "water": [self._water_to_dict(w) for w in waters],
            "workouts": workouts,
            "steps": [self._step_to_dict(s) for s in steps_rows],
            "steps_total": steps_total,
        }

    def log_meal(
        self,
        *,
        description: str,
        meal_type: str = "snack",
        calories: float = 0,
        protein_g: float = 0,
        fat_g: float = 0,
        carbs_g: float = 0,
        source: str = "llm",
        estimated: bool = True,
    ) -> dict[str, Any]:
        row = FoodLog(
            user_id=self.user_id,
            meal_type=meal_type[:32],
            description=description[:2000],
            calories=calories,
            protein_g=protein_g,
            fat_g=fat_g,
            carbs_g=carbs_g,
            source=source[:32],
            estimated=estimated,
        )
        self.db.add(row)
        self.db.commit()
        self.db.refresh(row)
        return {"ok": True, "meal": self._food_to_dict(row)}

    def log_water(self, amount_ml: int) -> dict[str, Any]:
        row = WaterLog(user_id=self.user_id, amount_ml=max(0, amount_ml))
        self.db.add(row)
        self.db.commit()
        self.db.refresh(row)
        return {"ok": True, "water": self._water_to_dict(row)}

    def log_steps(
        self,
        steps: int,
        *,
        active_calories: float | None = None,
        logged_at: datetime | str | None = None,
        day: date | None = None,
        days_ago: int | None = None,
        notes: str = "",
        source: str = "manual",
    ) -> dict[str, Any]:
        row = StepLog(
            user_id=self.user_id,
            steps=max(0, int(steps)),
            active_calories=active_calories,
            notes=notes[:2000],
            source=source[:32],
            logged_at=self._resolve_logged_at(
                logged_at=logged_at,
                day=day,
                days_ago=days_ago,
            ),
        )
        self.db.add(row)
        self.db.commit()
        self.db.refresh(row)
        return {"ok": True, "step_log": self._step_to_dict(row)}

    def log_weight(
        self,
        weight_kg: float,
        *,
        body_fat_pct: float | None = None,
        chest_cm: float | None = None,
        waist_cm: float | None = None,
        neck_cm: float | None = None,
        hip_cm: float | None = None,
        notes: str = "",
        recorded_at: datetime | str | None = None,
        day: date | None = None,
        days_ago: int | None = None,
    ) -> dict[str, Any]:
        profile = self.get_profile() or {}
        sex = profile.get("sex") or "male"
        height_cm = float(profile.get("height_cm") or 170)

        computed = compute_body_composition(
            sex=str(sex),
            height_cm=height_cm,
            weight_kg=weight_kg,
            neck_cm=neck_cm,
            waist_cm=waist_cm,
            hip_cm=hip_cm,
            body_fat_pct=body_fat_pct,
        )

        row = BodyMetric(
            user_id=self.user_id,
            weight_kg=weight_kg,
            body_fat_pct=computed.get("body_fat_pct"),
            body_fat_method=computed.get("body_fat_method"),
            chest_cm=chest_cm,
            waist_cm=waist_cm,
            neck_cm=neck_cm,
            hip_cm=hip_cm,
            whr=computed.get("whr"),
            lbm_kg=computed.get("lbm_kg"),
            ffmi=computed.get("ffmi"),
            notes=notes[:1000],
            recorded_at=self._resolve_logged_at(
                logged_at=recorded_at,
                day=day,
                days_ago=days_ago,
            ),
        )
        self.db.add(row)
        profile_row = self._get_profile_row()
        if profile_row:
            profile_row.weight_kg = weight_kg
            targets = compute_targets(
                {
                    "sex": profile_row.sex,
                    "age": profile_row.age,
                    "height_cm": profile_row.height_cm,
                    "weight_kg": weight_kg,
                    "activity_level": profile_row.activity_level,
                    "goal": profile_row.goal,
                }
            )
            profile_row.calorie_target = targets["calorie_target"]
            profile_row.protein_g = targets["protein_g"]
            profile_row.fat_g = targets["fat_g"]
            profile_row.carbs_g = targets["carbs_g"]
            profile_row.water_l = targets["water_l"]
        self.db.commit()
        self.db.refresh(row)
        metric = self._body_metric_to_dict(row)
        return {
            "ok": True,
            "metric": metric,
            "computed": {
                "body_fat_pct": computed.get("body_fat_pct"),
                "body_fat_method": computed.get("body_fat_method"),
                "whr": computed.get("whr"),
                "lbm_kg": computed.get("lbm_kg"),
                "ffmi": computed.get("ffmi"),
                "warnings": computed.get("warnings") or [],
            },
        }

    def log_workout(
        self,
        *,
        title: str,
        notes: str = "",
        duration_min: int | None = None,
        exercises: list[dict[str, Any]] | None = None,
        active_calories: float | None = None,
        total_calories: float | None = None,
        steps: int | None = None,
        logged_at: datetime | str | None = None,
        day: date | None = None,
        days_ago: int | None = None,
    ) -> dict[str, Any]:
        row = WorkoutLog(
            user_id=self.user_id,
            title=title[:255],
            notes=notes[:2000],
            duration_min=duration_min,
            active_calories=active_calories,
            total_calories=total_calories,
            steps=steps,
            exercises_json=json.dumps(exercises or [], ensure_ascii=False),
            logged_at=self._resolve_logged_at(
                logged_at=logged_at,
                day=day,
                days_ago=days_ago,
            ),
        )
        self.db.add(row)
        self.db.commit()
        self.db.refresh(row)
        return {"ok": True, "workout": self._workout_to_dict(row)}

    def get_workout_stats(
        self,
        *,
        days: int = 7,
        end_day: date | None = None,
    ) -> dict[str, Any]:
        days = max(1, min(days, 90))
        end = end_day or datetime.now(timezone.utc).date()
        start = end - timedelta(days=days - 1)
        start_dt, _ = self._day_bounds(start)
        _, end_dt = self._day_bounds(end)

        rows = self.db.scalars(
            select(WorkoutLog)
            .where(WorkoutLog.user_id == self.user_id, WorkoutLog.logged_at >= start_dt, WorkoutLog.logged_at <= end_dt)
            .order_by(WorkoutLog.logged_at)
        ).all()

        profile = self.get_profile() or {}
        weekly_target = int(profile.get("weekly_workouts") or 3)

        count = len(rows)
        duration_min = sum(r.duration_min or 0 for r in rows)
        active_kcal = round(
            sum(estimate_workout_active_kcal(self._workout_to_dict(r)) for r in rows),
            1,
        )

        days_with_workout: set[date] = set()
        for row in rows:
            if row.logged_at:
                days_with_workout.add(row.logged_at.astimezone(timezone.utc).date())

        streak = 0
        cursor = end
        while cursor >= start:
            if cursor in days_with_workout:
                streak += 1
                cursor -= timedelta(days=1)
            else:
                break

        return {
            "days": days,
            "start_date": start.isoformat(),
            "end_date": end.isoformat(),
            "count": count,
            "duration_min": duration_min,
            "active_kcal": active_kcal,
            "weekly_target": weekly_target,
            "streak": streak,
        }


    def list_body_metrics(self, limit: int = 30) -> list[dict[str, Any]]:
        rows = self.db.scalars(
            select(BodyMetric).where(BodyMetric.user_id == self.user_id).order_by(BodyMetric.recorded_at.desc()).limit(limit)
        ).all()
        return [self._body_metric_to_dict(r) for r in rows]

    def delete_food_log(self, log_id: int) -> bool:
        row = self.db.get(FoodLog, log_id)
        if not row or row.user_id != self.user_id:
            return False
        self.db.delete(row)
        self.db.commit()
        return True

    def delete_water_log(self, log_id: int) -> bool:
        row = self.db.get(WaterLog, log_id)
        if not row or row.user_id != self.user_id:
            return False
        self.db.delete(row)
        self.db.commit()
        return True

    def delete_workout_log(self, log_id: int) -> bool:
        row = self.db.get(WorkoutLog, log_id)
        if not row or row.user_id != self.user_id:
            return False
        self.db.delete(row)
        self.db.commit()
        return True

    def delete_step_log(self, log_id: int) -> bool:
        row = self.db.get(StepLog, log_id)
        if not row or row.user_id != self.user_id:
            return False
        self.db.delete(row)
        self.db.commit()
        return True

    def list_reminders(self) -> list[dict[str, Any]]:
        rows = self.db.scalars(select(FitnessReminder).where(FitnessReminder.user_id == self.user_id).order_by(FitnessReminder.kind)).all()
        return [self._reminder_to_dict(r) for r in rows]

    def set_reminder(
        self,
        kind: str,
        *,
        enabled: bool | None = None,
        hour: int | None = None,
        minute: int | None = None,
        interval_hours: int | None = None,
    ) -> dict[str, Any]:
        row = self.db.scalar(
            select(FitnessReminder).where(FitnessReminder.user_id == self.user_id, FitnessReminder.kind == kind)
        )
        if not row:
            row = FitnessReminder(user_id=self.user_id, kind=kind)
            self.db.add(row)
        if enabled is not None:
            row.enabled = enabled
        if hour is not None:
            row.hour = hour
        if minute is not None:
            row.minute = minute
        if interval_hours is not None:
            row.interval_hours = interval_hours
        self.db.commit()
        self.db.refresh(row)
        return {"ok": True, "reminder": self._reminder_to_dict(row)}

    def calc_one_rm(self, weight_kg: float, reps: int) -> dict[str, Any]:
        return {"ok": True, "one_rm_kg": one_rep_max(weight_kg, reps)}

    def get_history(
        self,
        *,
        days: int = 7,
        end_day: date | None = None,
        include_targets_base: bool = True,
    ) -> dict[str, Any]:
        days = max(1, min(days, 90))
        end = end_day or datetime.now(timezone.utc).date()
        start = end - timedelta(days=days - 1)
        summaries: list[dict[str, Any]] = []

        for offset in range(days):
            d = start + timedelta(days=offset)
            full = self.get_daily_summary(d)
            totals = full["totals"]
            has_data = bool(full["meals"] or full["water"] or full["workouts"] or full["steps"])
            item: dict[str, Any] = {
                "date": full["date"],
                "has_data": has_data,
                "totals": totals,
                "targets": full["targets"],
                "meal_count": len(full["meals"]),
                "workout_count": len(full["workouts"]),
            }
            if include_targets_base:
                item["targets_base"] = full.get("targets_base")
            summaries.append(item)

        return {
            "start_date": start.isoformat(),
            "end_date": end.isoformat(),
            "days": days,
            "summaries": summaries,
        }

    def snapshot(self) -> dict[str, Any]:
        today = datetime.now(timezone.utc).date()
        return {
            "profile": self.get_profile(),
            "today": self.get_daily_summary(today),
            "history": self.get_history(days=7, end_day=today),
            "workout_stats": self.get_workout_stats(days=7, end_day=today),
            "body_metrics": self.list_body_metrics(limit=10),
            "reminders": self.list_reminders(),
        }

    def get_charts(
        self,
        *,
        weeks: int = 52,
        trend: bool = True,
        end_day: date | None = None,
    ) -> dict[str, Any]:
        from app.fitness.charts import build_fitness_charts

        return build_fitness_charts(
            self.db,
            self.user_id,
            weeks=weeks,
            trend=trend,
            end_day=end_day,
        )

    @staticmethod
    def _food_to_dict(row: FoodLog) -> dict[str, Any]:
        return {
            "id": row.id,
            "meal_type": row.meal_type,
            "description": row.description,
            "calories": row.calories,
            "protein_g": row.protein_g,
            "fat_g": row.fat_g,
            "carbs_g": row.carbs_g,
            "source": row.source,
            "estimated": row.estimated,
            "logged_at": row.logged_at.isoformat() if row.logged_at else None,
        }

    @staticmethod
    def _water_to_dict(row: WaterLog) -> dict[str, Any]:
        return {
            "id": row.id,
            "amount_ml": row.amount_ml,
            "logged_at": row.logged_at.isoformat() if row.logged_at else None,
        }

    @staticmethod
    def _step_to_dict(row: StepLog) -> dict[str, Any]:
        return {
            "id": row.id,
            "steps": row.steps,
            "active_calories": row.active_calories,
            "source": row.source,
            "notes": row.notes,
            "logged_at": row.logged_at.isoformat() if row.logged_at else None,
        }

    @staticmethod
    def _workout_to_dict(row: WorkoutLog) -> dict[str, Any]:
        try:
            exercises = json.loads(row.exercises_json or "[]")
        except json.JSONDecodeError:
            exercises = []
        return {
            "id": row.id,
            "title": row.title,
            "notes": row.notes,
            "duration_min": row.duration_min,
            "active_calories": row.active_calories,
            "total_calories": row.total_calories,
            "steps": row.steps,
            "exercises": exercises,
            "logged_at": row.logged_at.isoformat() if row.logged_at else None,
        }

    @staticmethod
    def _reminder_to_dict(row: FitnessReminder) -> dict[str, Any]:
        return {
            "id": row.id,
            "kind": row.kind,
            "hour": row.hour,
            "minute": row.minute,
            "interval_hours": row.interval_hours,
            "enabled": row.enabled,
            "last_fired_at": row.last_fired_at.isoformat() if row.last_fired_at else None,
        }