defmodule PestControl do
  @moduledoc """
  Pest Control Cost Calculator — Elixir Engine

  Built by Treebark Termite and Pest Control
  https://treebarktermiteandpestcontrol.com
  """

  @pest_base_rates %{
    "subterranean_termite" => 0.55,
    "drywood_termite" => 0.65,
    "dampwood_termite" => 0.50,
    "ants" => 0.12,
    "cockroaches" => 0.14,
    "spiders" => 0.10,
    "rodents" => 0.20,
    "fleas" => 0.15,
    "general_pest" => 0.12,
    "multi_pest" => 0.22
  }

  @treatment_multipliers %{
    "liquid_barrier" => 1.0,
    "bait_stations" => 0.6,
    "fumigation" => 2.2,
    "heat_treatment" => 1.8,
    "spot_treatment" => 0.4,
    "ipm" => 0.9,
    "organic" => 1.1
  }

  @severity_multipliers %{
    "preventive" => 0.6,
    "light" => 0.85,
    "moderate" => 1.0,
    "severe" => 1.5
  }

  @frequency_factors %{
    "one_time" => 1.0,
    "annual" => 0.95,
    "quarterly" => 0.85,
    "bimonthly" => 0.80,
    "monthly" => 0.70
  }

  @treatments_per_year %{
    "one_time" => 1,
    "annual" => 1,
    "quarterly" => 4,
    "bimonthly" => 6,
    "monthly" => 12
  }

  @access_multipliers %{
    "standard" => 1.0,
    "crawl_space" => 1.25,
    "attic" => 1.20,
    "multi_story" => 1.35,
    "slab_drill" => 1.50
  }

  @property_minimums %{
    "single_family" => 150,
    "multi_family" => 250,
    "condo" => 120,
    "commercial_office" => 350,
    "restaurant" => 300,
    "warehouse" => 400
  }

  @regional_multipliers %{
    "orange_county" => 1.10,
    "los_angeles_county" => 1.05,
    "riverside_county" => 0.90
  }

  @seasonal_adjustments %{
    "Q1" => 0.95,
    "Q2" => 1.15,
    "Q3" => 1.05,
    "Q4" => 1.00
  }

  @addon_costs %{
    "wdi_wdo_inspection" => 150,
    "exclusion_sealing" => 350,
    "attic_insulation_treatment" => 500,
    "termite_damage_repair_estimate" => 0
  }

  @labor_ratio 0.65
  @default_margin 0.25
  @termite_types ["subterranean_termite", "drywood_termite", "dampwood_termite"]

  def calculate(params) do
    pest_type = params.pest_type
    property_sqft = params.property_sqft
    profit_margin = Map.get(params, :profit_margin, @default_margin)
    quarter = Map.get(params, :quarter, "Q2")
    addons = Map.get(params, :addons, [])

    base_rate = Map.get(@pest_base_rates, pest_type, 0.12)
    minimum = Map.get(@property_minimums, params.property_type, 150)
    raw_cost = max(base_rate * property_sqft, minimum)

    treat_mult = Map.get(@treatment_multipliers, params.treatment_method, 1.0)
    sev_mult = Map.get(@severity_multipliers, params.infestation_severity, 1.0)
    acc_mult = Map.get(@access_multipliers, params.access_difficulty, 1.0)
    reg_mult = Map.get(@regional_multipliers, params.region, 1.0)
    sea_mult = Map.get(@seasonal_adjustments, quarter, 1.0)

    adjusted = raw_cost * treat_mult * sev_mult * acc_mult * reg_mult * sea_mult

    labor = Float.round(adjusted * @labor_ratio, 2)
    materials = Float.round(adjusted * (1 - @labor_ratio), 2)
    subtotal = Float.round(labor + materials, 2)

    margin_amount = Float.round(subtotal * profit_margin, 2)
    per_treatment = Float.round(subtotal + margin_amount, 2)

    addon_total = Enum.reduce(addons, 0, fn a, acc -> acc + Map.get(@addon_costs, a, 0) end)
    per_treatment_total = Float.round(per_treatment + addon_total, 2)

    freq_factor = Map.get(@frequency_factors, params.service_frequency, 1.0)
    treats_year = Map.get(@treatments_per_year, params.service_frequency, 1)
    annual_per = Float.round(per_treatment_total * freq_factor, 2)
    annual_total = Float.round(annual_per * treats_year, 2)

    cost_per_sqft =
      if property_sqft > 0,
        do: Float.round(per_treatment_total / property_sqft, 4),
        else: 0

    {fumigation, savings} =
      if pest_type in @termite_types do
        fum_adj = raw_cost * 2.2 * sev_mult * acc_mult * reg_mult * sea_mult
        fum = Float.round(fum_adj * (1.0 + profit_margin), 2)
        {fum, Float.round(fum - per_treatment_total, 2)}
      else
        {nil, nil}
      end

    %{
      per_treatment_cost: per_treatment_total,
      cost_per_sqft: cost_per_sqft,
      annual_total: annual_total,
      fumigation_comparison: fumigation,
      savings_vs_fumigation: savings
    }
  end
end