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import gym
import pandas as pd
import numpy as np
import random
from gym.spaces import Box

random.seed(42)
np.random.seed(42)

class SolarSys(gym.Env):
    """
    Flat (non-hierarchical) OpenAI Gym Environment for Multi-Agent energy management 
    in a residential cluster, featuring complex P2P pricing and reward structures 
    similar to the low-level agents in the Hierarchical model.
    """

    def __init__(
        self,
        data_path: str = "./data/training/simulated_data.csv",
        state: str = "region_a",  # Generalized: region_a, region_b, region_c
        time_freq: str = "15T", 
    ):
        
        super().__init__()
        self.data_path = data_path
        self.time_freq = time_freq
        self.state = state.lower()

        # --- Generalized Pricing Configuration ---
        self._pricing_info = {
            "region_a": {
                "max_grid_price": 0.2112,
                "feed_in_tariff": 0.04,
                "price_function": self._get_region_a_price
            },
            "region_b": {
                "max_grid_price": 0.32,
                "feed_in_tariff": 0.055,
                "price_function": self._get_region_b_price
            },
            "region_c": {
                "max_grid_price": 0.12505,
                "feed_in_tariff": 0.06,
                "price_function": self._get_region_c_price
            }
        }

        if self.state not in self._pricing_info:
            raise ValueError(f"State '{self.state}' is not supported. Available states: {list(self._pricing_info.keys())}")
        
        state_config = self._pricing_info[self.state]
        self.max_grid_price = state_config["max_grid_price"]
        self.feed_in_tariff = state_config["feed_in_tariff"]
        self._get_price_function = state_config["price_function"]

        # --- Data Loading ---
        try:
            all_data = pd.read_csv(data_path)
            all_data["local_15min"] = pd.to_datetime(all_data["local_15min"], utc=True)
            all_data.set_index("local_15min", inplace=True)
            all_data = all_data.resample(time_freq).mean() 

        except FileNotFoundError:
            raise FileNotFoundError(f"Data file {data_path} not found.")
        except pd.errors.EmptyDataError:
            raise ValueError(f"Data file {data_path} is empty.")
        except Exception as e:
            raise ValueError(f"Error loading data: {e}")

        # Compute global maxima for normalization
        grid_cols = [c for c in all_data.columns if c.startswith("grid_")]
        solar_cols = [c for c in all_data.columns if c.startswith("total_solar_")]
        all_grid = all_data[grid_cols].values
        all_solar = all_data[solar_cols].values

        self.global_max_demand = float((all_grid + all_solar).max()) + 1e-8
        self.global_max_solar = float(all_solar.max()) + 1e-8

        self.all_data = all_data
        
        # Calculate time steps
        freq_offset = pd.tseries.frequencies.to_offset(time_freq)
        minutes_per_step = freq_offset.nanos / 1e9 / 60.0
        self.steps_per_day = int(24 * 60 // minutes_per_step)

        total_rows = len(self.all_data)
        self.total_days = total_rows // self.steps_per_day
        if self.total_days < 1:
            raise ValueError("Dataset has less than a single day of data.")

        self.house_ids = [
            col.split("_")[1] for col in self.all_data.columns
            if col.startswith("grid_")
        ]
        self.num_agents = len(self.house_ids)
        self.original_no_p2p_import = {}
        for hid in self.house_ids:
            col_grid = f"grid_{hid}"
            self.original_no_p2p_import[hid] = self.all_data[col_grid].clip(lower=0.0).values
        
        # Determine population groups and battery assignments
        solar_sums = self.all_data[solar_cols].sum(axis=0).to_dict()
        self.agent_groups = [
            1 if solar_sums[f"total_solar_{hid}"] > 0 else 0 for hid in self.house_ids
        ]
        self.solar_houses = [
            hid for hid in self.house_ids if self.agent_groups[self.house_ids.index(hid)] == 1
        ]

        self.battery_options = {
            "teslapowerwall": {"max_capacity": 13.5, "charge_efficiency": 0.95, "discharge_efficiency": 0.90, "max_charge_rate": 5.0, "max_discharge_rate": 5.0, "degradation_cost_per_kwh": 0.005},
            "enphase":         {"max_capacity": 5.0,  "charge_efficiency": 0.95, "discharge_efficiency": 0.90, "max_charge_rate": 2.0, "max_discharge_rate": 2.0, "degradation_cost_per_kwh": 0.005},
            "franklin":        {"max_capacity": 15.0, "charge_efficiency": 0.95, "discharge_efficiency": 0.90, "max_charge_rate": 6.0, "max_discharge_rate": 6.0, "degradation_cost_per_kwh": 0.005},
        }
        
        # Initialize battery specs as vectorized arrays (Crucial for speed)
        self.batteries = {}
        self.has_battery = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_max_capacity = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_charge_efficiency = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_discharge_efficiency = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_max_charge_rate = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_max_discharge_rate = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_degradation_cost = np.zeros(self.num_agents, dtype=np.float32)
        self.battery_soc = np.zeros(self.num_agents, dtype=np.float32)
        
        for i, hid in enumerate(self.house_ids):
            if hid in self.solar_houses:
                choice = random.choice(list(self.battery_options))
                specs = self.battery_options[choice]
                self.batteries[hid] = specs 
                
                self.has_battery[i] = 1.0
                self.battery_max_capacity[i] = specs["max_capacity"]
                self.battery_charge_efficiency[i] = specs["charge_efficiency"]
                self.battery_discharge_efficiency[i] = specs["discharge_efficiency"]
                self.battery_max_charge_rate[i] = specs["max_charge_rate"]
                self.battery_max_discharge_rate[i] = specs["max_discharge_rate"]
                self.battery_degradation_cost[i] = specs["degradation_cost_per_kwh"]

        # Observation & Action Spaces
        # [demand, solar, SOC_frac, grid_price, peer_price, total_demand_others, total_solar_others, hour]
        self.observation_space = Box(
            low=-np.inf, high=np.inf,
            shape=(self.num_agents, 8),
            dtype=np.float32
        )
        
        # Action: [sell_grid, buy_grid, sell_peers, buy_peers, charge_batt, discharge_batt]
        self.action_space = Box(
            low=0.0,
            high=1.0,
            shape=(self.num_agents, 6),
            dtype=np.float32
        )
        
        self.episode_metrics = {}
        self._initialize_episode_metrics()
        
        # Initialize episode variables
        self.data = None
        self.demands_day = None
        self.solars_day = None
        self.hours_day = None
        self.current_step = 0
        self.num_steps = self.steps_per_day  
        self.previous_actions = np.zeros((self.num_agents, 6), dtype=np.float32)


    def _initialize_episode_metrics(self):
        """Initialize or reset all metrics tracked over a single episode."""
        self.cumulative_grid_reduction = 0.0
        self.cumulative_grid_reduction_peak = 0.0
        self.cumulative_degradation_cost = 0.0
        self.agent_cost_savings = np.zeros(self.num_agents, dtype=np.float32)
        self.degradation_cost_timeseries = []
        self.cost_savings_timeseries = []
        self.grid_reduction_timeseries = []


    # --- Price Functions (Generalized) ---
    def get_grid_price(self, step_idx):
        """Return grid price for the current step."""
        return self._get_price_function(step_idx)

    def _get_region_a_price(self, step_idx):
        minutes_per_step = 24 * 60 / self.steps_per_day
        hour = int((step_idx * minutes_per_step) // 60) % 24
        if 14 <= hour < 19:
            return 0.2112
        else:
            return 0.0434

    def _get_region_b_price(self, step_idx):
        minutes_per_step = 24 * 60 / self.steps_per_day
        hour = int((step_idx * minutes_per_step) // 60) % 24
        if 15 <= hour < 19:
            return 0.32
        elif 13 <= hour < 15:
            return 0.22
        else:
            return 0.12

    def _get_region_c_price(self, step_idx):
        minutes_per_step = 24 * 60 / self.steps_per_day
        hour = int((step_idx * minutes_per_step) // 60) % 24
        if 13 <= hour < 21:
            return 0.125048
        elif hour >= 23 or hour < 6:
            return 0.057014
        else:
            return 0.079085

    def get_peer_price(self, step_idx, total_surplus, total_shortfall):
        """
        Calculates P2P price based on supply/demand ratio (Arctangent-log approach).
        This matches the logic used in the Hierarchical model's coordination layer.
        """
        grid_price = self.get_grid_price(step_idx)
        feed_in_tariff = self.feed_in_tariff
        
        # Parameters for arctangent-log pricing
        p_balance = (grid_price * 0.80) + (feed_in_tariff * 0.20)
        p_con = (grid_price - feed_in_tariff) / (1.5 * np.pi)
        k = 1.5 
        epsilon = 1e-6
        supply = total_surplus + epsilon
        demand = total_shortfall + epsilon
        
        ratio = demand / supply
        log_ratio = np.log(ratio)
        if log_ratio < 0:
            power_term = - (np.abs(log_ratio) ** k)
        else:
            power_term = log_ratio ** k
        
        price_offset = 2 * np.pi * p_con * np.arctan(power_term)
        
        peer_price = p_balance + price_offset
        
        final_price = float(np.clip(peer_price, feed_in_tariff, grid_price))
        
        return final_price


    def reset(self):
        # 1. Store metrics from completed episode
        if self.current_step > 0:
            positive_savings = self.agent_cost_savings[self.agent_cost_savings > 0]
            fairness_on_savings = self._compute_jains_index(positive_savings) if len(positive_savings) > 1 else 0.0
            self.episode_metrics = {
                "total_cost_savings": np.sum(self.agent_cost_savings),
                "fairness_on_cost_savings": fairness_on_savings,
                "battery_degradation_cost_total": self.cumulative_degradation_cost,
                # ... other metrics ...
            }
        
        # 2. Select random day and load data
        self.day_index = np.random.randint(0, self.total_days)
        start_row = self.day_index * self.steps_per_day
        end_row = start_row + self.steps_per_day
        day_data = self.all_data.iloc[start_row:end_row].copy()
        self.data = day_data  

        # 3. Process Demand and Solar into Vectorized Arrays
        demand_list = []
        solar_list = []
        for hid in self.house_ids:
            col_grid = f"grid_{hid}"
            col_solar = f"total_solar_{hid}"
            grid_series = day_data[col_grid].fillna(0.0)
            solar_series = day_data[col_solar].fillna(0.0).clip(lower=0.0)
            demand_array = grid_series.values + solar_series.values
            demand_array = np.clip(demand_array, 0.0, None)
            demand_list.append(demand_array)
            solar_list.append(solar_series.values)

        self.demands_day = np.stack(demand_list, axis=1).astype(np.float32)
        self.solars_day = np.stack(solar_list, axis=1).astype(np.float32)
        self.hours_day = (self.data.index.hour + self.data.index.minute / 60.0).values
        
        self.no_p2p_import_day = np.stack(
            [self.original_no_p2p_import[hid][start_row:end_row] for hid in self.house_ids], axis=1
        )

        # 4. Reset episode metrics and step counter
        self.current_step = 0
        self._initialize_episode_metrics()
        self.previous_actions = np.zeros((self.num_agents, 6), dtype=np.float32)
        
        # 5. Randomize battery SOC (30%–70%)
        lows = 0.30 * self.battery_max_capacity
        highs = 0.70 * self.battery_max_capacity
        self.battery_soc = np.random.uniform(low=lows, high=highs)
        self.battery_soc *= self.has_battery # Ensure non-battery homes remain zero

        # 6. Return initial observation
        obs = self._get_obs()
        return obs, {}


    def step(self, actions):
        actions = np.clip(np.array(actions, dtype=np.float32), 0.0, 1.0)
        
        a_sellGrid, a_buyGrid, a_sellPeers, a_buyPeers, a_chargeBatt, a_dischargeBatt = actions.T
        
        demands = self.demands_day[self.current_step]
        solars  = self.solars_day[self.current_step]

        # 1. Pricing
        total_surplus   = np.maximum(solars  - demands, 0.0).sum()
        total_shortfall = np.maximum(demands - solars,  0.0).sum()
        peer_price      = self.get_peer_price(self.current_step, total_surplus, total_shortfall)
        grid_price      = self.get_grid_price(self.current_step)
        feed_in_tariff  = self.feed_in_tariff
        
        # Initial balances (self-use enforced first)
        final_shortfall = np.maximum(demands - solars, 0.0)
        final_surplus   = np.maximum(solars  - demands, 0.0)
        
        # --- 2. VECTORIZED BATTERY DISCHARGE ---
        available_from_batt = self.battery_soc * self.battery_discharge_efficiency
        desired_discharge = a_dischargeBatt * self.battery_max_discharge_rate
        discharge_amount = np.minimum.reduce([desired_discharge, available_from_batt, final_shortfall])
        discharge_amount *= self.has_battery 

        # Update SOC and shortfall
        self.battery_soc -= (discharge_amount / (self.battery_discharge_efficiency + 1e-9)) * self.has_battery
        self.battery_soc = np.maximum(0.0, self.battery_soc)
        final_shortfall -= discharge_amount

        # --- 3. VECTORIZED BATTERY CHARGE ---
        cap_left = self.battery_max_capacity - self.battery_soc
        desired_charge = a_chargeBatt * self.battery_max_charge_rate
        charge_limit = cap_left / (self.battery_charge_efficiency + 1e-9)
        charge_amount = np.minimum.reduce([desired_charge, charge_limit, final_surplus])
        charge_amount *= self.has_battery 

        # Update SOC and surplus
        self.battery_soc += charge_amount * self.battery_charge_efficiency
        final_surplus -= charge_amount

        # --- 4. VECTORIZED P2P TRADING ---
        battery_offer = (self.battery_soc * self.battery_discharge_efficiency) * self.has_battery
        effective_surplus = final_surplus + battery_offer

        netPeer = a_buyPeers - a_sellPeers
        p2p_buy_request = np.maximum(0, netPeer) * final_shortfall
        p2p_sell_offer = np.maximum(0, -netPeer) * effective_surplus

        total_sell = np.sum(p2p_sell_offer)
        total_buy  = np.sum(p2p_buy_request)
        matched    = min(total_sell, total_buy)

        if matched > 1e-9:
            sell_fraction = p2p_sell_offer / (total_sell + 1e-12)
            buy_fraction  = p2p_buy_request / (total_buy + 1e-12)
            actual_sold   = matched * sell_fraction
            actual_bought = matched * buy_fraction
        else:
            actual_sold   = np.zeros(self.num_agents, dtype=np.float32)
            actual_bought = np.zeros(self.num_agents, dtype=np.float32)
        
        # Track energy source for sale
        from_batt_p2p = np.minimum(actual_sold, battery_offer)
        from_solar_p2p = actual_sold - from_batt_p2p

        # Update balances
        final_surplus -= from_solar_p2p
        final_shortfall -= actual_bought
        
        # Deduct peer battery sales from SOC
        soc_reduction_p2p = (from_batt_p2p / (self.battery_discharge_efficiency + 1e-9)) * self.has_battery
        self.battery_soc -= soc_reduction_p2p
        self.battery_soc = np.maximum(0.0, self.battery_soc) 
                
        # --- 5. GRID TRADES ---
        netGrid = a_buyGrid - a_sellGrid
        grid_import = np.maximum(0, netGrid) * final_shortfall
        grid_export = np.maximum(0, -netGrid) * final_surplus
        
        # Any remaining shortfall must be imported (uncontrolled import)
        forced_import = np.maximum(final_shortfall - grid_import, 0.0)
        grid_import += forced_import
        
        # --- 6. COSTS AND REWARDS ---
        costs = (
            (grid_import * grid_price)
            - (grid_export * feed_in_tariff)
            + (actual_bought * peer_price)
            - (actual_sold * peer_price)
        )
       
        final_rewards = self._compute_rewards(
            grid_import, grid_export, actual_sold, actual_bought,
            charge_amount, discharge_amount, costs, grid_price, peer_price
        )

        # --- 7. Metric Logging ---
        no_p2p_import_this_step = self.no_p2p_import_day[self.current_step]
        
        step_grid_reduction = np.sum(no_p2p_import_this_step - grid_import)
        self.cumulative_grid_reduction += step_grid_reduction
        self.grid_reduction_timeseries.append(step_grid_reduction)
        if grid_price >= self.max_grid_price * 0.99:
            self.cumulative_grid_reduction_peak += step_grid_reduction

        cost_no_p2p = no_p2p_import_this_step * grid_price
        step_cost_savings_per_agent = cost_no_p2p - costs
        self.agent_cost_savings += step_cost_savings_per_agent
        self.cost_savings_timeseries.append(np.sum(step_cost_savings_per_agent))

        degradation_cost_agent = (charge_amount + discharge_amount) * self.battery_degradation_cost
        step_degradation_cost = np.sum(degradation_cost_agent)
        self.cumulative_degradation_cost += step_degradation_cost
        self.degradation_cost_timeseries.append(step_degradation_cost)
        
        info = {
            "p2p_buy": actual_bought, "p2p_sell": actual_sold,
            "grid_import_with_p2p": grid_import, "grid_import_no_p2p": no_p2p_import_this_step,
            "grid_export": grid_export, "costs": costs,
            "charge_amount": charge_amount, "discharge_amount": discharge_amount,
            "step": self.current_step, "agent_rewards": final_rewards,
        }

        # --- 8. Finalize Step ---
        self.current_step += 1
        done = (self.current_step >= self.num_steps)
        obs_next = self._get_obs()

        # Output required format for gym multi-agent environment
        rewards_list = list(final_rewards)
        return obs_next, rewards_list, done, info
    

    def _get_obs(self):
        step = min(self.current_step, self.num_steps - 1)
        demands = self.demands_day[step]
        solars  = self.solars_day[step]
        
        # Compute market aggregates
        total_surplus = float(np.maximum(solars - demands, 0.0).sum())
        total_shortfall = float(np.maximum(demands - solars, 0.0).sum())

        grid_price = self.get_grid_price(step)
        peer_price = self.get_peer_price(step, total_surplus, total_shortfall)
        hour = self.hours_day[step]
        
        # Compute SOC fraction for all agents (-1 for non-battery agents)
        soc_frac = self.battery_soc / (self.battery_max_capacity + 1e-9)
        soc_frac = np.where(self.has_battery == 1, soc_frac, -1.0)
        
        # Vectorized Observation Construction
        obs = np.stack([
            demands,
            solars,
            soc_frac,
            np.full(self.num_agents, grid_price),
            np.full(self.num_agents, peer_price),
            demands.sum() - demands, # Total demand of others
            solars.sum() - solars,   # Total solar of others
            np.full(self.num_agents, hour)
        ], axis=1).astype(np.float32)

        return obs


    def _compute_jains_index(self, usage_array):
        """Simple Jain's Fairness Index."""
        x = np.array(usage_array, dtype=np.float32)
        numerator = (np.sum(x))**2
        denominator = len(x) * np.sum(x**2) + 1e-8
        return numerator / denominator


    def _compute_rewards(
        self, grid_import, grid_export, actual_sold, actual_bought,
        charge_amount, discharge_amount, costs, grid_price, peer_price
    ):
        """Calculates the weighted, combined reward for all agents (vectorized)."""
        
        # Weights (must match the hierarchical model's weights)
        w1 = 0.3; w2 = 0.5; w3 = 0.5; w4 = 0.1; w5 = 0.05; w6 = 0.4; w7 = 1.0

        # Jain's index on total P2P volume
        jfi = self._compute_jains_index(actual_bought + actual_sold)

        # Normalize prices
        p_grid_norm = grid_price / self.max_grid_price
        p_peer_norm = peer_price / self.max_grid_price

        # Base reward: Negative costs (minimize expenditure)
        rewards = -costs * w7

        # 1. Grid import penalty (w1)
        rewards -= w1 * grid_import * p_grid_norm

        # 2. P2P sell bonus (w2)
        rewards += w2 * actual_sold * p_peer_norm

        # 3. P2P buy bonus (w3): only if peer price is better than grid price
        buy_bonus_factor = (grid_price - peer_price) / self.max_grid_price
        buy_bonus = w3 * actual_bought * buy_bonus_factor
        rewards += np.where(peer_price < grid_price, buy_bonus, 0.0)

        # 4. SOC deviation penalty (w4): only for agents with batteries
        soc_frac = self.battery_soc / (self.battery_max_capacity + 1e-9)
        soc_penalties = w4 * ((soc_frac - 0.5) ** 2) * self.has_battery
        rewards -= soc_penalties

        # 5. Battery degradation penalty (w5)
        degrad_penalties = w5 * (charge_amount + discharge_amount) * self.battery_degradation_cost
        rewards -= degrad_penalties

        # 6. Fairness bonus (w6): applied equally to all agents in the cluster
        rewards += w6 * jfi
        
        return rewards


    def get_episode_metrics(self):
        """Return performance metrics for the last completed episode."""
        return self.episode_metrics