global_func/optimize_lineup.py

import pandas as pd
import numpy as np
from ortools.linear_solver import pywraplp

from global_func.exposure_spread import check_position_eligibility


def get_effective_salary(player_name: str, column_name: str, map_dict: dict, type_var: str) -> float:
    """Calculate the effective salary for a player in a specific column (handles CPT multiplier)"""
    base_salary = map_dict['salary_map'].get(player_name, 0)
    if type_var != 'Classic' and column_name == 'CPT':
        return base_salary * 1.5
    return base_salary


def optimize_single_lineup(
    row: pd.Series,
    player_columns: list,
    player_pool: pd.DataFrame,
    map_dict: dict,
    lock_teams: list,
    type_var: str,
    sport_var: str,
    salary_max: int,
    optimize_by: str = 'median'
) -> pd.Series:
    """
    Optimize a single lineup row using linear programming.
    
    Players from lock_teams are kept (locked), all other positions are cleared
    and re-optimized using OR-Tools linear solver.
    
    Args:
        row: A single lineup row from the DataFrame
        player_columns: List of column names containing player positions
        player_pool: DataFrame of available players (projections_df)
        map_dict: Dictionary containing player mappings
        lock_teams: List of team names whose players should be KEPT (locked)
        type_var: 'Classic' or 'Showdown'
        sport_var: Sport identifier (NFL, NBA, MLB, etc.)
        salary_max: Maximum salary cap for the lineup
        optimize_by: 'median' or 'ownership' - which metric to optimize for
        
    Returns:
        Optimized row with potentially upgraded players
    """
    # Create a copy of the row to modify
    optimized_row = row.copy()
    
    # Identify locked players (from lock_teams) and open positions
    locked_players = {}  # {column: player_name}
    open_columns = []
    locked_salary = 0
    locked_player_names = set()
    
    for col in player_columns:
        player_name = row[col]
        player_team = map_dict['team_map'].get(player_name, '')
        
        if player_team in lock_teams:
            # Keep this player locked
            locked_players[col] = player_name
            locked_salary += get_effective_salary(player_name, col, map_dict, type_var)
            locked_player_names.add(player_name)
        else:
            # This position is open for optimization
            open_columns.append(col)
    
    # If no open columns, nothing to optimize
    if not open_columns:
        return optimized_row
    
    # Calculate remaining salary budget
    remaining_salary = salary_max - locked_salary
    
    # Filter player pool: exclude locked teams and already-locked players
    available_players = player_pool[
        (~player_pool['team'].isin(lock_teams)) & 
        (~player_pool['player_names'].isin(locked_player_names))
    ].copy()
    
    if available_players.empty:
        return optimized_row
    
    # Build the optimization model
    solver = pywraplp.Solver.CreateSolver('CBC')
    if not solver:
        # Fallback if solver not available
        return optimized_row
    
    # Create decision variables: x[player_idx, col_idx] = 1 if player is assigned to column
    player_list = available_players.to_dict('records')
    num_players = len(player_list)
    num_open_cols = len(open_columns)
    
    # x[i][j] = 1 if player i is assigned to open column j
    x = {}
    for i in range(num_players):
        for j in range(num_open_cols):
            x[i, j] = solver.BoolVar(f'x_{i}_{j}')
    
    # Constraint 1: Each open column gets exactly one player
    for j in range(num_open_cols):
        solver.Add(sum(x[i, j] for i in range(num_players)) == 1)
    
    # Constraint 2: Each player can only be used once across all open columns
    for i in range(num_players):
        solver.Add(sum(x[i, j] for j in range(num_open_cols)) <= 1)
    
    # Constraint 3: Position eligibility
    for i, player in enumerate(player_list):
        player_positions = player['position'].split('/')
        for j, col in enumerate(open_columns):
            if type_var == 'Classic':
                if not check_position_eligibility(sport_var, col, player_positions):
                    solver.Add(x[i, j] == 0)
            else:
                # For Showdown, CPT and FLEX can take any player
                pass
    
    # Constraint 4: Total salary of selected players <= remaining_salary
    salary_constraint = []
    for i, player in enumerate(player_list):
        for j, col in enumerate(open_columns):
            effective_salary = get_effective_salary(player['player_names'], col, map_dict, type_var)
            salary_constraint.append(x[i, j] * effective_salary)
    solver.Add(sum(salary_constraint) <= remaining_salary)
    
    # Objective: Maximize the sum of the optimization metric
    objective_terms = []
    for i, player in enumerate(player_list):
        metric_value = player.get(optimize_by, player.get('median', 0))
        for j in range(num_open_cols):
            objective_terms.append(x[i, j] * metric_value)
    
    solver.Maximize(sum(objective_terms))
    
    # Solve
    status = solver.Solve()
    
    if status == pywraplp.Solver.OPTIMAL or status == pywraplp.Solver.FEASIBLE:
        # Extract solution
        for j, col in enumerate(open_columns):
            for i, player in enumerate(player_list):
                if x[i, j].solution_value() > 0.5:
                    optimized_row[col] = player['player_names']
                    break
    
    return optimized_row


def optimize_lineup(
    working_frame: pd.DataFrame,
    projections_df: pd.DataFrame,
    player_columns: list,
    map_dict: dict,
    lock_teams: list,
    site_var: str,
    type_var: str,
    sport_var: str,
    salary_max: int,
    optimize_by: str = 'median'
) -> pd.DataFrame:
    """
    Optimize all lineups in a portfolio using linear programming.
    
    Players from lock_teams are kept (locked), all other positions are cleared
    and re-optimized to find the best combination that fits the salary cap.
    
    Args:
        working_frame: DataFrame containing lineups to optimize
        projections_df: DataFrame with player projections (must have columns: 
                       player_names, team, position, salary, median, ownership)
        player_columns: List of column names containing player positions
        map_dict: Dictionary containing player mappings
        lock_teams: List of team names whose players should be KEPT (locked).
                   All other players will be cleared and re-optimized.
        site_var: 'Draftkings' or 'Fanduel'
        type_var: 'Classic' or 'Showdown'
        sport_var: Sport identifier (NFL, NBA, MLB, etc.)
        salary_max: Maximum salary cap for lineups
        optimize_by: 'median' or 'ownership' - which metric to optimize for (higher is better)
        
    Returns:
        DataFrame with optimized lineups
    """
    # Create a copy to avoid modifying the original
    optimized_frame = working_frame.copy()
    
    # Optimize each row
    for idx in optimized_frame.index:
        row = optimized_frame.loc[idx]
        optimized_row = optimize_single_lineup(
            row=row,
            player_columns=player_columns,
            player_pool=projections_df,
            map_dict=map_dict,
            lock_teams=lock_teams if lock_teams else [],
            type_var=type_var,
            sport_var=sport_var,
            salary_max=salary_max,
            optimize_by=optimize_by
        )
        optimized_frame.loc[idx] = optimized_row
    
    return optimized_frame