defmodule DaProductApp.RiskManagement.Seeds do
  @moduledoc """
  Seeds for Risk Management - creates default risk rules for all merchant categories.
  """
  
  alias DaProductApp.Repo
  alias DaProductApp.RiskManagement.RiskRule

  def seed_risk_rules do
    categories = ["Cat A", "Cat B", "Cat C", "Cat D"]
    
    rules_definitions = [
      %{
        name: "Suspicious International transactions",
        description: "International card transactions with value ≥ AED 10,000",
        rule_type: "hold",
        execution_order: 1,
        mcc_codes: [],
        parameters: %{
          "threshold" => 10000,
          "card_types" => ["international"],
          "currency" => "AED"
        }
      },
      %{
        name: "Multiple Int'l card, low value",
        description: "2+ international transactions, same terminal, 2,000–5,000 AED within 30 minutes",
        rule_type: "hold",
        execution_order: 2,
        mcc_codes: [],
        parameters: %{
          "min_amount" => 2000,
          "max_amount" => 5000,
          "min_count" => 2,
          "time_window_minutes" => 30,
          "card_types" => ["international"]
        }
      },
      %{
        name: "Abnormal Time transaction",
        description: "Transactions between 12AM–7AM, except certain MCCs",
        rule_type: "hold",
        execution_order: 3,
        mcc_codes: [],
        parameters: %{
          "start_hour" => 0,
          "end_hour" => 7,
          "excluded_mccs" => ["8062", "7011", "5542", "5812"]
        }
      },
      %{
        name: "Split transaction",
        description: "Same card+terminal+city, ≤10 minutes, sum ≥ AED 10,000",
        rule_type: "hold",
        execution_order: 4,
        mcc_codes: [],
        parameters: %{
          "time_window_minutes" => 10,
          "sum_threshold" => 10000,
          "grouping_fields" => ["card_number", "terminal_id", "location"]
        }
      },
      %{
        name: "Duplicate transaction",
        description: "Same card+terminal+amount, ≤10 minutes, sum ≥ AED 10,000",
        rule_type: "hold",
        execution_order: 5,
        mcc_codes: [],
        parameters: %{
          "time_window_minutes" => 10,
          "sum_threshold" => 10000,
          "grouping_fields" => ["card_number", "terminal_id", "amount"]
        }
      },
      %{
        name: "High Velocity transaction",
        description: "Same terminal, ≤2 minutes, value ≥ AED 500",
        rule_type: "hold",
        execution_order: 6,
        mcc_codes: [],
        parameters: %{
          "time_window_minutes" => 2,
          "amount_threshold" => 500,
          "grouping_fields" => ["terminal_id"]
        }
      },
      %{
        name: "Above-average ticket size",
        description: "≥4x average ticket size on specific MCCs",
        rule_type: "hold",
        execution_order: 7,
        mcc_codes: ["4812", "5732", "5733", "5541"],
        parameters: %{
          "multiplier" => 4.0,
          "rolling_days" => 30,
          "target_mccs" => ["4812", "5732", "5733", "5541"]
        }
      },
      %{
        name: "Dormant Merchant",
        description: "Transaction after 30 days of inactivity",
        rule_type: "hold",
        execution_order: 8,
        mcc_codes: [],
        parameters: %{
          "inactivity_days" => 30
        }
      },
      %{
        name: "High Value Transaction",
        description: "Single transaction value ≥ AED 10,000",
        rule_type: "hold",
        execution_order: 9,
        mcc_codes: [],
        parameters: %{
          "threshold" => 10000,
          "currency" => "AED"
        }
      },
      %{
        name: "High Frequency Chargeback Merchant",
        description: "Merchant with 2+ chargebacks in 30 days",
        rule_type: "hold",
        execution_order: 10,
        mcc_codes: [],
        parameters: %{
          "chargeback_count" => 2,
          "period_days" => 30
        }
      },
      %{
        name: "Excessive Refunds/Reversals",
        description: "Refund/reversal rate >10% in 30 days",
        rule_type: "alert",
        execution_order: 11,
        mcc_codes: [],
        parameters: %{
          "refund_rate_threshold" => 0.10,
          "period_days" => 30
        }
      },
      %{
        name: "Out-of-Profile Geographic",
        description: "Unusual card geography pattern",
        rule_type: "hold",
        execution_order: 12,
        mcc_codes: [],
        parameters: %{
          "analysis_window_days" => 30,
          "deviation_threshold" => 3.0
        }
      },
      %{
        name: "Round Figure Transaction on same Terminal",
        description: "High frequency of round figure transactions (multiples of 100) - >25% in last 90 days",
        rule_type: "hold",
        execution_order: 13,
        mcc_codes: [],
        parameters: %{
          "round_figure_threshold_percent" => 0.25,
          "period_days" => 90,
          "round_multiples" => [100, 1000]
        }
      },
      %{
        name: "Transaction followed by Fraud-Suspect declined (Same Card)",
        description: "Transaction followed by fraud-suspect declined transaction with same card",
        rule_type: "hold",
        execution_order: 14,
        mcc_codes: [],
        parameters: %{
          "fraud_response_codes" => ["04", "07", "41", "43", "59", "63", "65", "67", "69"],
          "time_window_minutes" => 60
        }
      },
      %{
        name: "Transaction followed by Fraud-Suspect declined (Different Card)",
        description: "Transaction followed by fraud-suspect declined with different card but same amount",
        rule_type: "hold",
        execution_order: 15,
        mcc_codes: [],
        parameters: %{
          "fraud_response_codes" => ["04", "07", "41", "43", "59", "63", "65", "67", "69"],
          "time_window_minutes" => 60
        }
      },
      %{
        name: "Transaction followed by Wrong PIN Entry Attempts",
        description: "Transaction followed by wrong PIN entry attempts (4+ attempts)",
        rule_type: "hold",
        execution_order: 16,
        mcc_codes: [],
        parameters: %{
          "wrong_pin_codes" => ["55", "75"],
          "attempt_threshold" => 4,
          "time_window_minutes" => 60
        }
      },
      %{
        name: "Daily Volume Above Average (4x)",
        description: "Daily transaction volume >= 4x average daily volume of last 90 days",
        rule_type: "hold",
        execution_order: 17,
        mcc_codes: [],
        parameters: %{
          "multiplier" => 4.0,
          "rolling_days" => 90
        }
      },
      %{
        name: "Multiple Transactions with Same Amount",
        description: "Multiple transactions (>5) with same amount at same terminal using different cards in 24hrs, sum >50,000 AED",
        rule_type: "hold",
        execution_order: 18,
        mcc_codes: [],
        parameters: %{
          "transaction_count_threshold" => 5,
          "time_window_hours" => 24,
          "sum_threshold" => 50_000
        }
      },
      %{
        name: "Self Card Transactions by Merchant",
        description: "Merchant using own card on own terminal, sum >2,000 AED in a day",
        rule_type: "hold",
        execution_order: 19,
        mcc_codes: [],
        parameters: %{
          "daily_threshold" => 2_000
        }
      },
      %{
        name: "Out-of-Profile Geographic Shift (Domestic to International)",
        description: "Merchant suddenly receives transactions from new international geographies",
        rule_type: "hold",
        execution_order: 20,
        mcc_codes: [],
        parameters: %{
          "analysis_window_days" => 30,
          "new_geography_threshold" => 0.20
        }
      },
      %{
        name: "High Chargeback Rate (>1%)",
        description: "Merchants with chargeback rate >1% in 30-day period",
        rule_type: "alert",
        execution_order: 21,
        mcc_codes: [],
        parameters: %{
          "chargeback_rate_threshold" => 0.01,
          "period_days" => 30
        }
      },
      %{
        name: "High Fraud Rate (>0.5%)",
        description: "Merchants with fraud rate >0.5% of total transactions in a calendar month",
        rule_type: "alert",
        execution_order: 22,
        mcc_codes: [],
        parameters: %{
          "fraud_rate_threshold" => 0.005,
          "period_days" => 30
        }
      },
      %{
        name: "Round or Unusual Amount Patterns (Alert)",
        description: "High proportion (>25%) of round figure transactions in 90-day window",
        rule_type: "alert",
        execution_order: 23,
        mcc_codes: [],
        parameters: %{
          "round_figure_threshold_percent" => 0.25,
          "period_days" => 90,
          "round_multiples" => [100, 1000]
        }
      },
      %{
        name: "High Decline/Authorization Failure Rate (>20%)",
        description: "Merchants where >20% of transaction attempts are declined",
        rule_type: "alert",
        execution_order: 24,
        mcc_codes: [],
        parameters: %{
          "decline_rate_threshold" => 0.20,
          "period_days" => 30
        }
      },
      %{
        name: "Sudden Drop in Daily Transaction Volume",
        description: "Daily volume drops >50% compared to 30-day average for 3 consecutive days",
        rule_type: "alert",
        execution_order: 25,
        mcc_codes: [],
        parameters: %{
          "drop_threshold_percent" => 0.50,
          "rolling_days" => 30,
          "consecutive_days" => 3
        }
      }
    ]

    # Create rules for each category with category-specific parameters
    for category <- categories do
      for rule_def <- rules_definitions do
        # Adjust parameters based on category
        adjusted_params = adjust_parameters_for_category(rule_def.parameters, category)
        
        attrs = %{
          name: rule_def.name,
          description: rule_def.description,
          category: category,
          rule_type: rule_def.rule_type,
          execution_order: rule_def.execution_order,
          mcc_codes: rule_def.mcc_codes,
          parameters: adjusted_params,
          enabled: true
        }
        
        case Repo.get_by(RiskRule, name: rule_def.name, category: category) do
          nil -> 
            %RiskRule{}
            |> RiskRule.changeset(attrs)
            |> Repo.insert!()
          existing -> 
            existing
            |> RiskRule.changeset(attrs)
            |> Repo.update!()
        end
      end
    end
    
    IO.puts("✅ Risk rules seeded successfully for all categories")
  end

  # Adjust rule parameters based on merchant category/risk tier
  defp adjust_parameters_for_category(base_params, category) do
    case category do
      "Cat A" -> # Enterprise Merchant - Lower thresholds, stricter rules
        base_params
        |> Map.put("threshold", Map.get(base_params, "threshold", 10000) * 0.8)
        |> Map.put("multiplier", Map.get(base_params, "multiplier", 4.0) * 0.8)
        
      "Cat B" -> # Mid-Market Merchant - Standard thresholds
        base_params
        
      "Cat C" -> # Known Entity - Slightly higher thresholds
        base_params
        |> Map.put("threshold", Map.get(base_params, "threshold", 10000) * 1.2)
        |> Map.put("multiplier", Map.get(base_params, "multiplier", 4.0) * 1.2)
        
      "Cat D" -> # SME/SMB - Higher thresholds, more lenient
        base_params
        |> Map.put("threshold", Map.get(base_params, "threshold", 10000) * 1.5)
        |> Map.put("multiplier", Map.get(base_params, "multiplier", 4.0) * 1.5)
        |> Map.put("time_window_minutes", Map.get(base_params, "time_window_minutes", 10) * 2)
        
      _ -> base_params
    end
  end
end