"""
Goal Utilities - Abstraction Layer for Focus Weights & Universal Value Fetcher

This module provides:
1. Abstraction layer between goal modes and focus weights (Phase 1)
2. Universal value fetcher for dynamic goal types (Phase 1.5)

Version History:
- V1 (Phase 1): Maps goal_mode to predefined weights
- V1.5 (Phase 1.5): Universal value fetcher for DB-registry goal types
- V2 (future): Reads from focus_areas table with custom user weights

Part of Phase 1 + Phase 1.5: Flexible Goal System
"""

from typing import Dict, Optional, Any
from datetime import date, timedelta
from decimal import Decimal
import json
from db import get_cursor


def get_focus_weights(conn, profile_id: str) -> Dict[str, float]:
    """
    Get focus area weights for a profile.

    This is an abstraction layer that will evolve:
    - V1 (now): Maps goal_mode → predefined weights
    - V2 (later): Reads from focus_areas table → custom user weights

    Args:
        conn: Database connection
        profile_id: User's profile ID

    Returns:
        Dict with focus weights (sum = 1.0):
        {
            'weight_loss': 0.3,    # Fat loss priority
            'muscle_gain': 0.2,    # Muscle gain priority
            'strength': 0.25,      # Strength training priority
            'endurance': 0.25,     # Cardio/endurance priority
            'flexibility': 0.0,    # Mobility priority
            'health': 0.0          # General health maintenance
        }

    Example Usage in Phase 0b:
        weights = get_focus_weights(conn, profile_id)

        # Score calculation considers user's focus
        overall_score = (
            body_score * weights['weight_loss'] +
            strength_score * weights['strength'] +
            cardio_score * weights['endurance']
        )
    """
    cur = get_cursor(conn)

    # Fetch current goal_mode
    cur.execute(
        "SELECT goal_mode FROM profiles WHERE id = %s",
        (profile_id,)
    )
    row = cur.fetchone()

    if not row:
        # Fallback: balanced health focus
        return {
            'weight_loss': 0.0,
            'muscle_gain': 0.0,
            'strength': 0.0,
            'endurance': 0.0,
            'flexibility': 0.0,
            'health': 1.0
        }

    goal_mode = row['goal_mode'] or 'health'

    # V1: Predefined weight mappings per goal_mode
    # These represent "typical" focus distributions for each mode
    WEIGHT_MAPPINGS = {
        'weight_loss': {
            'weight_loss': 0.60,   # Primary: fat loss
            'endurance': 0.20,     # Support: cardio for calorie burn
            'muscle_gain': 0.0,    # Not compatible
            'strength': 0.10,      # Maintain muscle during deficit
            'flexibility': 0.05,   # Minor: mobility work
            'health': 0.05         # Minor: general wellness
        },
        'strength': {
            'strength': 0.50,      # Primary: strength gains
            'muscle_gain': 0.40,   # Support: hypertrophy
            'endurance': 0.10,     # Minor: work capacity
            'weight_loss': 0.0,    # Not compatible with strength focus
            'flexibility': 0.0,
            'health': 0.0
        },
        'endurance': {
            'endurance': 0.70,     # Primary: aerobic capacity
            'health': 0.20,        # Support: cardiovascular health
            'flexibility': 0.10,   # Support: mobility for running
            'weight_loss': 0.0,
            'muscle_gain': 0.0,
            'strength': 0.0
        },
        'recomposition': {
            'weight_loss': 0.30,   # Equal: lose fat
            'muscle_gain': 0.30,   # Equal: gain muscle
            'strength': 0.25,      # Support: progressive overload
            'endurance': 0.10,     # Minor: conditioning
            'flexibility': 0.05,   # Minor: mobility
            'health': 0.0
        },
        'health': {
            'health': 0.50,        # Primary: general wellness
            'endurance': 0.20,     # Support: cardio health
            'flexibility': 0.15,   # Support: mobility
            'strength': 0.10,      # Support: functional strength
            'weight_loss': 0.05,   # Minor: maintain healthy weight
            'muscle_gain': 0.0
        }
    }

    return WEIGHT_MAPPINGS.get(goal_mode, WEIGHT_MAPPINGS['health'])


def get_primary_focus(conn, profile_id: str) -> str:
    """
    Get the primary focus area for a profile.

    Returns the focus area with the highest weight.
    Useful for UI labels and simple decision logic.

    Args:
        conn: Database connection
        profile_id: User's profile ID

    Returns:
        Primary focus area name (e.g., 'weight_loss', 'strength')
    """
    weights = get_focus_weights(conn, profile_id)
    return max(weights.items(), key=lambda x: x[1])[0]


def get_focus_description(focus_area: str) -> str:
    """
    Get human-readable description for a focus area.

    Args:
        focus_area: Focus area key (e.g., 'weight_loss')

    Returns:
        German description for UI display
    """
    descriptions = {
        'weight_loss': 'Gewichtsreduktion & Fettabbau',
        'muscle_gain': 'Muskelaufbau & Hypertrophie',
        'strength': 'Kraftsteigerung & Performance',
        'endurance': 'Ausdauer & aerobe Kapazität',
        'flexibility': 'Beweglichkeit & Mobilität',
        'health': 'Allgemeine Gesundheit & Erhaltung'
    }
    return descriptions.get(focus_area, focus_area)


# ============================================================================
# Phase 1.5: Universal Value Fetcher for Dynamic Goal Types
# ============================================================================

def get_goal_type_config(conn, type_key: str) -> Optional[Dict[str, Any]]:
    """
    Get goal type configuration from database registry.

    Args:
        conn: Database connection
        type_key: Goal type key (e.g., 'weight', 'meditation_minutes')

    Returns:
        Dict with config or None if not found/inactive
    """
    cur = get_cursor(conn)

    cur.execute("""
        SELECT type_key, source_table, source_column, aggregation_method,
               calculation_formula, label_de, unit, icon, category
        FROM goal_type_definitions
        WHERE type_key = %s AND is_active = true
        LIMIT 1
    """, (type_key,))

    return cur.fetchone()


def get_current_value_for_goal(conn, profile_id: str, goal_type: str) -> Optional[float]:
    """
    Universal value fetcher for any goal type.

    Reads configuration from goal_type_definitions table and executes
    appropriate query based on aggregation_method or calculation_formula.

    Args:
        conn: Database connection
        profile_id: User's profile ID
        goal_type: Goal type key (e.g., 'weight', 'meditation_minutes')

    Returns:
        Current value as float or None if not available
    """
    config = get_goal_type_config(conn, goal_type)

    if not config:
        print(f"[WARNING] Goal type '{goal_type}' not found or inactive")
        return None

    # Complex calculation (e.g., lean_mass)
    if config['calculation_formula']:
        return _execute_calculation_formula(conn, profile_id, config['calculation_formula'])

    # Simple aggregation
    return _fetch_by_aggregation_method(
        conn,
        profile_id,
        config['source_table'],
        config['source_column'],
        config['aggregation_method']
    )


def _fetch_by_aggregation_method(
    conn,
    profile_id: str,
    table: str,
    column: str,
    method: str
) -> Optional[float]:
    """
    Fetch value using specified aggregation method.

    Supported methods:
    - latest: Most recent value
    - avg_7d: 7-day average
    - avg_30d: 30-day average
    - sum_30d: 30-day sum
    - count_7d: Count of entries in last 7 days
    - count_30d: Count of entries in last 30 days
    - min_30d: Minimum value in last 30 days
    - max_30d: Maximum value in last 30 days
    """
    cur = get_cursor(conn)

    if method == 'latest':
        cur.execute(f"""
            SELECT {column} FROM {table}
            WHERE profile_id = %s AND {column} IS NOT NULL
            ORDER BY date DESC LIMIT 1
        """, (profile_id,))
        row = cur.fetchone()
        return float(row[column]) if row else None

    elif method == 'avg_7d':
        days_ago = date.today() - timedelta(days=7)
        cur.execute(f"""
            SELECT AVG({column}) as avg_value FROM {table}
            WHERE profile_id = %s AND date >= %s AND {column} IS NOT NULL
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['avg_value']) if row and row['avg_value'] is not None else None

    elif method == 'avg_30d':
        days_ago = date.today() - timedelta(days=30)
        cur.execute(f"""
            SELECT AVG({column}) as avg_value FROM {table}
            WHERE profile_id = %s AND date >= %s AND {column} IS NOT NULL
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['avg_value']) if row and row['avg_value'] is not None else None

    elif method == 'sum_30d':
        days_ago = date.today() - timedelta(days=30)
        cur.execute(f"""
            SELECT SUM({column}) as sum_value FROM {table}
            WHERE profile_id = %s AND date >= %s AND {column} IS NOT NULL
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['sum_value']) if row and row['sum_value'] is not None else None

    elif method == 'count_7d':
        days_ago = date.today() - timedelta(days=7)
        cur.execute(f"""
            SELECT COUNT(*) as count_value FROM {table}
            WHERE profile_id = %s AND date >= %s
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['count_value']) if row else 0.0

    elif method == 'count_30d':
        days_ago = date.today() - timedelta(days=30)
        cur.execute(f"""
            SELECT COUNT(*) as count_value FROM {table}
            WHERE profile_id = %s AND date >= %s
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['count_value']) if row else 0.0

    elif method == 'min_30d':
        days_ago = date.today() - timedelta(days=30)
        cur.execute(f"""
            SELECT MIN({column}) as min_value FROM {table}
            WHERE profile_id = %s AND date >= %s AND {column} IS NOT NULL
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['min_value']) if row and row['min_value'] is not None else None

    elif method == 'max_30d':
        days_ago = date.today() - timedelta(days=30)
        cur.execute(f"""
            SELECT MAX({column}) as max_value FROM {table}
            WHERE profile_id = %s AND date >= %s AND {column} IS NOT NULL
        """, (profile_id, days_ago))
        row = cur.fetchone()
        return float(row['max_value']) if row and row['max_value'] is not None else None

    else:
        print(f"[WARNING] Unknown aggregation method: {method}")
        return None


def _execute_calculation_formula(conn, profile_id: str, formula_json: str) -> Optional[float]:
    """
    Execute complex calculation formula.

    Currently supports:
    - lean_mass: weight - (weight * body_fat_pct / 100)

    Future: Parse JSON formula and execute dynamically.

    Args:
        conn: Database connection
        profile_id: User's profile ID
        formula_json: JSON string with calculation config

    Returns:
        Calculated value or None
    """
    try:
        formula = json.loads(formula_json)
        calc_type = formula.get('type')

        if calc_type == 'lean_mass':
            # Get dependencies
            cur = get_cursor(conn)

            cur.execute("""
                SELECT weight FROM weight_log
                WHERE profile_id = %s
                ORDER BY date DESC LIMIT 1
            """, (profile_id,))
            weight_row = cur.fetchone()

            cur.execute("""
                SELECT body_fat_pct FROM caliper_log
                WHERE profile_id = %s
                ORDER BY date DESC LIMIT 1
            """, (profile_id,))
            bf_row = cur.fetchone()

            if weight_row and bf_row:
                weight = float(weight_row['weight'])
                bf_pct = float(bf_row['body_fat_pct'])
                lean_mass = weight - (weight * bf_pct / 100.0)
                return round(lean_mass, 2)

            return None

        else:
            print(f"[WARNING] Unknown calculation type: {calc_type}")
            return None

    except (json.JSONDecodeError, KeyError, ValueError, TypeError) as e:
        print(f"[ERROR] Formula execution failed: {e}, formula={formula_json}")
        return None


# Future V2 Implementation (commented out for reference):
"""
def get_focus_weights_v2(conn, profile_id: str) -> Dict[str, float]:
    '''V2: Read from focus_areas table with custom user weights'''
    cur = get_cursor(conn)

    cur.execute('''
        SELECT weight_loss_pct, muscle_gain_pct, endurance_pct,
               strength_pct, flexibility_pct, health_pct
        FROM focus_areas
        WHERE profile_id = %s AND active = true
        LIMIT 1
    ''', (profile_id,))

    row = cur.fetchone()

    if not row:
        # Fallback to V1 behavior
        return get_focus_weights(conn, profile_id)

    # Convert percentages to weights (0-1 range)
    return {
        'weight_loss': row['weight_loss_pct'] / 100.0,
        'muscle_gain': row['muscle_gain_pct'] / 100.0,
        'endurance': row['endurance_pct'] / 100.0,
        'strength': row['strength_pct'] / 100.0,
        'flexibility': row['flexibility_pct'] / 100.0,
        'health': row['health_pct'] / 100.0
    }
"""