"""
Vitals Router - Resting HR + HRV Tracking
v9d Phase 2: Vitals Module

Endpoints:
- GET    /api/vitals              List vitals (with limit)
- GET    /api/vitals/by-date/{date}  Get vitals for specific date
- POST   /api/vitals              Create/update vitals (upsert)
- PUT    /api/vitals/{id}         Update vitals
- DELETE /api/vitals/{id}         Delete vitals
- GET    /api/vitals/stats        Get vitals statistics
"""
from fastapi import APIRouter, HTTPException, Depends, Header
from pydantic import BaseModel
from typing import Optional
from datetime import datetime, timedelta
import logging

from db import get_db, get_cursor, r2d
from auth import require_auth

router = APIRouter(prefix="/api/vitals", tags=["vitals"])
logger = logging.getLogger(__name__)


class VitalsEntry(BaseModel):
    date: str
    resting_hr: Optional[int] = None
    hrv: Optional[int] = None
    blood_pressure_systolic: Optional[int] = None
    blood_pressure_diastolic: Optional[int] = None
    pulse: Optional[int] = None
    vo2_max: Optional[float] = None
    spo2: Optional[int] = None
    respiratory_rate: Optional[float] = None
    irregular_heartbeat: Optional[bool] = None
    possible_afib: Optional[bool] = None
    note: Optional[str] = None


class VitalsUpdate(BaseModel):
    date: Optional[str] = None
    resting_hr: Optional[int] = None
    hrv: Optional[int] = None
    blood_pressure_systolic: Optional[int] = None
    blood_pressure_diastolic: Optional[int] = None
    pulse: Optional[int] = None
    vo2_max: Optional[float] = None
    spo2: Optional[int] = None
    respiratory_rate: Optional[float] = None
    irregular_heartbeat: Optional[bool] = None
    possible_afib: Optional[bool] = None
    note: Optional[str] = None


def get_pid(x_profile_id: Optional[str], session: dict) -> str:
    """Extract profile_id from session (never from header for security)."""
    return session['profile_id']


@router.get("")
def list_vitals(
    limit: int = 90,
    x_profile_id: Optional[str] = Header(default=None),
    session: dict = Depends(require_auth)
):
    """Get vitals entries for current profile."""
    pid = get_pid(x_profile_id, session)
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute(
            """
            SELECT id, profile_id, date, resting_hr, hrv,
                   blood_pressure_systolic, blood_pressure_diastolic, pulse,
                   vo2_max, spo2, respiratory_rate,
                   irregular_heartbeat, possible_afib,
                   note, source, created_at, updated_at
            FROM vitals_log
            WHERE profile_id = %s
            ORDER BY date DESC
            LIMIT %s
            """,
            (pid, limit)
        )
        return [r2d(r) for r in cur.fetchall()]


@router.get("/by-date/{date}")
def get_vitals_by_date(
    date: str,
    x_profile_id: Optional[str] = Header(default=None),
    session: dict = Depends(require_auth)
):
    """Get vitals entry for a specific date."""
    pid = get_pid(x_profile_id, session)
    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute(
            """
            SELECT id, profile_id, date, resting_hr, hrv,
                   blood_pressure_systolic, blood_pressure_diastolic, pulse,
                   vo2_max, spo2, respiratory_rate,
                   irregular_heartbeat, possible_afib,
                   note, source, created_at, updated_at
            FROM vitals_log
            WHERE profile_id = %s AND date = %s
            """,
            (pid, date)
        )
        row = cur.fetchone()
        if not row:
            raise HTTPException(404, "Keine Vitalwerte für dieses Datum gefunden")
        return r2d(row)


@router.post("")
def create_vitals(
    entry: VitalsEntry,
    x_profile_id: Optional[str] = Header(default=None),
    session: dict = Depends(require_auth)
):
    """Create or update vitals entry (upsert)."""
    pid = get_pid(x_profile_id, session)

    # Validation: at least one vital must be provided
    has_data = any([
        entry.resting_hr, entry.hrv, entry.blood_pressure_systolic,
        entry.blood_pressure_diastolic, entry.vo2_max, entry.spo2,
        entry.respiratory_rate
    ])
    if not has_data:
        raise HTTPException(400, "Mindestens ein Vitalwert muss angegeben werden")

    with get_db() as conn:
        cur = get_cursor(conn)

        # Upsert: insert or update if date already exists
        cur.execute(
            """
            INSERT INTO vitals_log (
                profile_id, date, resting_hr, hrv,
                blood_pressure_systolic, blood_pressure_diastolic, pulse,
                vo2_max, spo2, respiratory_rate,
                irregular_heartbeat, possible_afib,
                note, source
            )
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, 'manual')
            ON CONFLICT (profile_id, date)
            DO UPDATE SET
                resting_hr = COALESCE(EXCLUDED.resting_hr, vitals_log.resting_hr),
                hrv = COALESCE(EXCLUDED.hrv, vitals_log.hrv),
                blood_pressure_systolic = COALESCE(EXCLUDED.blood_pressure_systolic, vitals_log.blood_pressure_systolic),
                blood_pressure_diastolic = COALESCE(EXCLUDED.blood_pressure_diastolic, vitals_log.blood_pressure_diastolic),
                pulse = COALESCE(EXCLUDED.pulse, vitals_log.pulse),
                vo2_max = COALESCE(EXCLUDED.vo2_max, vitals_log.vo2_max),
                spo2 = COALESCE(EXCLUDED.spo2, vitals_log.spo2),
                respiratory_rate = COALESCE(EXCLUDED.respiratory_rate, vitals_log.respiratory_rate),
                irregular_heartbeat = COALESCE(EXCLUDED.irregular_heartbeat, vitals_log.irregular_heartbeat),
                possible_afib = COALESCE(EXCLUDED.possible_afib, vitals_log.possible_afib),
                note = COALESCE(EXCLUDED.note, vitals_log.note),
                updated_at = CURRENT_TIMESTAMP
            RETURNING id, profile_id, date, resting_hr, hrv,
                      blood_pressure_systolic, blood_pressure_diastolic, pulse,
                      vo2_max, spo2, respiratory_rate,
                      irregular_heartbeat, possible_afib,
                      note, source, created_at, updated_at
            """,
            (pid, entry.date, entry.resting_hr, entry.hrv,
             entry.blood_pressure_systolic, entry.blood_pressure_diastolic, entry.pulse,
             entry.vo2_max, entry.spo2, entry.respiratory_rate,
             entry.irregular_heartbeat, entry.possible_afib,
             entry.note)
        )
        row = cur.fetchone()
        conn.commit()

        logger.info(f"[VITALS] Upserted vitals for {pid} on {entry.date}")
        return r2d(row)


@router.put("/{vitals_id}")
def update_vitals(
    vitals_id: int,
    updates: VitalsUpdate,
    x_profile_id: Optional[str] = Header(default=None),
    session: dict = Depends(require_auth)
):
    """Update existing vitals entry."""
    pid = get_pid(x_profile_id, session)

    with get_db() as conn:
        cur = get_cursor(conn)

        # Check ownership
        cur.execute(
            "SELECT id FROM vitals_log WHERE id = %s AND profile_id = %s",
            (vitals_id, pid)
        )
        if not cur.fetchone():
            raise HTTPException(404, "Eintrag nicht gefunden")

        # Build update query dynamically
        fields = []
        values = []

        if updates.date is not None:
            fields.append("date = %s")
            values.append(updates.date)
        if updates.resting_hr is not None:
            fields.append("resting_hr = %s")
            values.append(updates.resting_hr)
        if updates.hrv is not None:
            fields.append("hrv = %s")
            values.append(updates.hrv)
        if updates.blood_pressure_systolic is not None:
            fields.append("blood_pressure_systolic = %s")
            values.append(updates.blood_pressure_systolic)
        if updates.blood_pressure_diastolic is not None:
            fields.append("blood_pressure_diastolic = %s")
            values.append(updates.blood_pressure_diastolic)
        if updates.pulse is not None:
            fields.append("pulse = %s")
            values.append(updates.pulse)
        if updates.vo2_max is not None:
            fields.append("vo2_max = %s")
            values.append(updates.vo2_max)
        if updates.spo2 is not None:
            fields.append("spo2 = %s")
            values.append(updates.spo2)
        if updates.respiratory_rate is not None:
            fields.append("respiratory_rate = %s")
            values.append(updates.respiratory_rate)
        if updates.irregular_heartbeat is not None:
            fields.append("irregular_heartbeat = %s")
            values.append(updates.irregular_heartbeat)
        if updates.possible_afib is not None:
            fields.append("possible_afib = %s")
            values.append(updates.possible_afib)
        if updates.note is not None:
            fields.append("note = %s")
            values.append(updates.note)

        if not fields:
            raise HTTPException(400, "Keine Änderungen angegeben")

        fields.append("updated_at = CURRENT_TIMESTAMP")
        values.append(vitals_id)

        query = f"""
            UPDATE vitals_log
            SET {', '.join(fields)}
            WHERE id = %s
            RETURNING id, profile_id, date, resting_hr, hrv,
                      blood_pressure_systolic, blood_pressure_diastolic, pulse,
                      vo2_max, spo2, respiratory_rate,
                      irregular_heartbeat, possible_afib,
                      note, source, created_at, updated_at
        """

        cur.execute(query, values)
        row = cur.fetchone()
        conn.commit()

        return r2d(row)


@router.delete("/{vitals_id}")
def delete_vitals(
    vitals_id: int,
    x_profile_id: Optional[str] = Header(default=None),
    session: dict = Depends(require_auth)
):
    """Delete vitals entry."""
    pid = get_pid(x_profile_id, session)

    with get_db() as conn:
        cur = get_cursor(conn)

        # Check ownership and delete
        cur.execute(
            "DELETE FROM vitals_log WHERE id = %s AND profile_id = %s RETURNING id",
            (vitals_id, pid)
        )
        if not cur.fetchone():
            raise HTTPException(404, "Eintrag nicht gefunden")

        conn.commit()
        logger.info(f"[VITALS] Deleted vitals {vitals_id} for {pid}")
        return {"message": "Eintrag gelöscht"}


@router.get("/stats")
def get_vitals_stats(
    days: int = 30,
    x_profile_id: Optional[str] = Header(default=None),
    session: dict = Depends(require_auth)
):
    """
    Get vitals statistics over the last N days.

    Returns:
    - avg_resting_hr (7d and 30d)
    - avg_hrv (7d and 30d)
    - trend (increasing/decreasing/stable)
    - latest values
    """
    pid = get_pid(x_profile_id, session)

    with get_db() as conn:
        cur = get_cursor(conn)

        # Get latest entry
        cur.execute(
            """
            SELECT date, resting_hr, hrv
            FROM vitals_log
            WHERE profile_id = %s AND date >= CURRENT_DATE - INTERVAL '%s days'
            ORDER BY date DESC
            LIMIT 1
            """,
            (pid, days)
        )
        latest = cur.fetchone()

        # Get averages (7d and 30d)
        cur.execute(
            """
            SELECT
                AVG(CASE WHEN date >= CURRENT_DATE - INTERVAL '7 days' THEN resting_hr END) as avg_hr_7d,
                AVG(CASE WHEN date >= CURRENT_DATE - INTERVAL '30 days' THEN resting_hr END) as avg_hr_30d,
                AVG(CASE WHEN date >= CURRENT_DATE - INTERVAL '7 days' THEN hrv END) as avg_hrv_7d,
                AVG(CASE WHEN date >= CURRENT_DATE - INTERVAL '30 days' THEN hrv END) as avg_hrv_30d,
                COUNT(*) as total_entries
            FROM vitals_log
            WHERE profile_id = %s AND date >= CURRENT_DATE - INTERVAL '%s days'
            """,
            (pid, max(days, 30))
        )
        stats_row = cur.fetchone()

        # Get entries for trend calculation (last 14 days)
        cur.execute(
            """
            SELECT date, resting_hr, hrv
            FROM vitals_log
            WHERE profile_id = %s AND date >= CURRENT_DATE - INTERVAL '14 days'
            ORDER BY date ASC
            """,
            (pid,)
        )
        entries = [r2d(r) for r in cur.fetchall()]

        # Simple trend calculation (compare first half vs second half)
        trend_hr = "stable"
        trend_hrv = "stable"

        if len(entries) >= 4:
            mid = len(entries) // 2
            first_half_hr = [e['resting_hr'] for e in entries[:mid] if e['resting_hr']]
            second_half_hr = [e['resting_hr'] for e in entries[mid:] if e['resting_hr']]

            if first_half_hr and second_half_hr:
                avg_first = sum(first_half_hr) / len(first_half_hr)
                avg_second = sum(second_half_hr) / len(second_half_hr)
                diff = avg_second - avg_first

                if diff > 2:
                    trend_hr = "increasing"
                elif diff < -2:
                    trend_hr = "decreasing"

            first_half_hrv = [e['hrv'] for e in entries[:mid] if e['hrv']]
            second_half_hrv = [e['hrv'] for e in entries[mid:] if e['hrv']]

            if first_half_hrv and second_half_hrv:
                avg_first_hrv = sum(first_half_hrv) / len(first_half_hrv)
                avg_second_hrv = sum(second_half_hrv) / len(second_half_hrv)
                diff_hrv = avg_second_hrv - avg_first_hrv

                if diff_hrv > 5:
                    trend_hrv = "increasing"
                elif diff_hrv < -5:
                    trend_hrv = "decreasing"

        return {
            "latest": r2d(latest) if latest else None,
            "avg_resting_hr_7d": round(stats_row['avg_hr_7d'], 1) if stats_row['avg_hr_7d'] else None,
            "avg_resting_hr_30d": round(stats_row['avg_hr_30d'], 1) if stats_row['avg_hr_30d'] else None,
            "avg_hrv_7d": round(stats_row['avg_hrv_7d'], 1) if stats_row['avg_hrv_7d'] else None,
            "avg_hrv_30d": round(stats_row['avg_hrv_30d'], 1) if stats_row['avg_hrv_30d'] else None,
            "total_entries": stats_row['total_entries'],
            "trend_resting_hr": trend_hr,
            "trend_hrv": trend_hrv,
            "period_days": days
        }