mitai-jinkendo/backend/data_layer/body_metrics.py

"""
Body Metrics Data Layer

Provides structured data for body composition and measurements.

Functions:
    - get_weight_trend_data(): Weight trend with slope and direction
    - get_body_composition_data(): Body fat percentage and lean mass
    - get_circumference_summary_data(): Latest circumference measurements

All functions return structured data (dict) without formatting.
Use placeholder_resolver.py for formatted strings for AI.

Phase 0c: Multi-Layer Architecture
Version: 1.0
"""

from typing import Dict, List, Optional, Tuple
from datetime import datetime, timedelta, date
from db import get_db, get_cursor, r2d
from data_layer.utils import calculate_confidence, safe_float


def get_weight_trend_data(
    profile_id: str,
    days: int = 28
) -> Dict:
    """
    Calculate weight trend with slope and direction.

    Args:
        profile_id: User profile ID
        days: Analysis window (default 28)

    Returns:
        {
            "first_value": float,
            "last_value": float,
            "delta": float,           # kg change
            "direction": str,         # "increasing" | "decreasing" | "stable"
            "data_points": int,
            "confidence": str,
            "days_analyzed": int,
            "first_date": date,
            "last_date": date
        }

    Confidence Rules:
        - high: >= 18 points (28d) or >= 4 points (7d)
        - medium: >= 12 points (28d) or >= 3 points (7d)
        - low: >= 8 points (28d) or >= 2 points (7d)
        - insufficient: < thresholds

    Migration from Phase 0b:
        OLD: get_weight_trend() returned formatted string
        NEW: Returns structured data for reuse in charts + AI
    """
    with get_db() as conn:
        cur = get_cursor(conn)
        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
        cur.execute(
            """SELECT weight, date FROM weight_log
               WHERE profile_id=%s AND date >= %s
               ORDER BY date""",
            (profile_id, cutoff)
        )
        rows = [r2d(r) for r in cur.fetchall()]

        # Calculate confidence
        confidence = calculate_confidence(len(rows), days, "general")

        # Early return if insufficient
        if confidence == 'insufficient' or len(rows) < 2:
            return {
                "confidence": "insufficient",
                "data_points": len(rows),
                "days_analyzed": days,
                "first_value": 0.0,
                "last_value": 0.0,
                "delta": 0.0,
                "direction": "unknown",
                "first_date": None,
                "last_date": None
            }

        # Extract values
        first_value = safe_float(rows[0]['weight'])
        last_value = safe_float(rows[-1]['weight'])
        delta = last_value - first_value

        # Determine direction
        if abs(delta) < 0.3:
            direction = "stable"
        elif delta > 0:
            direction = "increasing"
        else:
            direction = "decreasing"

        return {
            "first_value": first_value,
            "last_value": last_value,
            "delta": delta,
            "direction": direction,
            "data_points": len(rows),
            "confidence": confidence,
            "days_analyzed": days,
            "first_date": rows[0]['date'],
            "last_date": rows[-1]['date']
        }


def get_body_composition_data(
    profile_id: str,
    days: int = 90
) -> Dict:
    """
    Get latest body composition data (body fat, lean mass).

    Args:
        profile_id: User profile ID
        days: Lookback window (default 90)

    Returns:
        {
            "body_fat_pct": float,
            "method": str,            # "jackson_pollock" | "durnin_womersley" | etc.
            "date": date,
            "confidence": str,
            "data_points": int
        }

    Migration from Phase 0b:
        OLD: get_latest_bf() returned formatted string "15.2%"
        NEW: Returns structured data {"body_fat_pct": 15.2, ...}
    """
    with get_db() as conn:
        cur = get_cursor(conn)
        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')

        cur.execute(
            """SELECT body_fat_pct, sf_method, date
               FROM caliper_log
               WHERE profile_id=%s
                 AND body_fat_pct IS NOT NULL
                 AND date >= %s
               ORDER BY date DESC
               LIMIT 1""",
            (profile_id, cutoff)
        )
        row = r2d(cur.fetchone()) if cur.rowcount > 0 else None

        if not row:
            return {
                "confidence": "insufficient",
                "data_points": 0,
                "body_fat_pct": 0.0,
                "method": None,
                "date": None
            }

        return {
            "body_fat_pct": safe_float(row['body_fat_pct']),
            "method": row.get('sf_method', 'unknown'),
            "date": row['date'],
            "confidence": "high",  # Latest measurement is always high confidence
            "data_points": 1
        }


def get_circumference_summary_data(
    profile_id: str,
    max_age_days: int = 90
) -> Dict:
    """
    Get latest circumference measurements for all body points.

    For each measurement point, fetches the most recent value (even if from different dates).
    Returns measurements with age in days for each point.

    Args:
        profile_id: User profile ID
        max_age_days: Maximum age of measurements to include (default 90)

    Returns:
        {
            "measurements": [
                {
                    "point": str,        # "Nacken", "Brust", etc.
                    "field": str,        # "c_neck", "c_chest", etc.
                    "value": float,      # cm
                    "date": date,
                    "age_days": int
                },
                ...
            ],
            "confidence": str,
            "data_points": int,
            "newest_date": date,
            "oldest_date": date
        }

    Migration from Phase 0b:
        OLD: get_circ_summary() returned formatted string "Nacken 38.0cm (vor 2 Tagen), ..."
        NEW: Returns structured array for charts + AI formatting
    """
    with get_db() as conn:
        cur = get_cursor(conn)

        # Define all circumference points
        fields = [
            ('c_neck', 'Nacken'),
            ('c_chest', 'Brust'),
            ('c_waist', 'Taille'),
            ('c_belly', 'Bauch'),
            ('c_hip', 'Hüfte'),
            ('c_thigh', 'Oberschenkel'),
            ('c_calf', 'Wade'),
            ('c_arm', 'Arm')
        ]

        measurements = []
        today = datetime.now().date()

        # Get latest value for each field individually
        for field_name, label in fields:
            cur.execute(
                f"""SELECT {field_name}, date,
                           CURRENT_DATE - date AS age_days
                    FROM circumference_log
                    WHERE profile_id=%s
                      AND {field_name} IS NOT NULL
                      AND date >= %s
                    ORDER BY date DESC
                    LIMIT 1""",
                (profile_id, (today - timedelta(days=max_age_days)).isoformat())
            )
            row = r2d(cur.fetchone()) if cur.rowcount > 0 else None

            if row:
                measurements.append({
                    "point": label,
                    "field": field_name,
                    "value": safe_float(row[field_name]),
                    "date": row['date'],
                    "age_days": row['age_days']
                })

        # Calculate confidence based on how many points we have
        confidence = calculate_confidence(len(measurements), 8, "general")

        if not measurements:
            return {
                "measurements": [],
                "confidence": "insufficient",
                "data_points": 0,
                "newest_date": None,
                "oldest_date": None
            }

        # Find newest and oldest dates
        dates = [m['date'] for m in measurements]
        newest_date = max(dates)
        oldest_date = min(dates)

        return {
            "measurements": measurements,
            "confidence": confidence,
            "data_points": len(measurements),
            "newest_date": newest_date,
            "oldest_date": oldest_date
        }