local Chrono_table = require 'maps.chronosphere.table'
local Balance = require 'maps.chronosphere.balance'
local Difficulty = require 'modules.difficulty_vote'
local Public = {}

local math_floor = math.floor
local math_min = math.min
local math_max = math.max
local math_abs = math.abs
local math_ceil = math.ceil

Public.tokens = {
  ["biters"] = {name = "token_biters", sprite = "virtual-signal/signal-B", tooltip = {"chronosphere.token_info_biters"}, enabled = false},
  ["ammo"] = {name = "token_ammo", sprite = "virtual-signal/signal-A", tooltip = {"chronosphere.token_info_ammo"}, enabled = true},
  ["tech"] = {name = "token_tech", sprite = "virtual-signal/signal-T", tooltip = {"chronosphere.token_info_tech"}, enabled = false},
  ["ecology"] = {name = "token_ecology", sprite = "virtual-signal/signal-E", tooltip = {"chronosphere.token_info_ecology"}, enabled = false},
  ["weapons"] = {name = "token_weapons", sprite = "virtual-signal/signal-W", tooltip = {"chronosphere.token_info_weapons"}, enabled = false}
}

function Public.add_ammo_tokens(player)
  local objective = Chrono_table.get_table()
  local inventory = player.get_inventory(defines.inventory.character_main)
  if not inventory or not inventory.valid then return end
  local count = inventory.remove({name = "pistol", count = 5})
  objective.research_tokens.ammo = objective.research_tokens.ammo + count
end

function Public.upgrade_count()
  --override the number here after adding new upgrades! Otherwise it won't work
  --(during reset it needs static number, at that point the list of upgrades isn't built yet!)
  return 25
end

function Public.upgrades()
  local objective = Chrono_table.get_table()
  local difficulty = Difficulty.get().difficulty_vote_value
  if not objective.upgrades then
    objective.upgrades = {}
    for i = 1, Public.upgrade_count(), 1 do
      objective.upgrades[i] = 0
    end
  end

  --Each upgrade is automatically added into gui.
  --name : visible name in gui (best if localized)
  --sprite: visible icon
  --cost/item/tt = the first part of localized string, for example coin is in item-name.coin. Can be even scenario's key.
  --Second part of localized string is taken from item's name.
  --First additional parameter for tooltip should match the max_level
  --still need to map upgrade effects in upgrades.lua / process_upgrade() if it should do more than increase level of upgrade
  --virtual token types need to match the names of chronotable.research_tokens[]
  local upgrades = {
    [1] = {
      name = {"chronosphere.upgrade_train_armor"},
      sprite = "recipe/locomotive",
      max_level = 36,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_train_armor_message"},
      tooltip = {"chronosphere.upgrade_train_armor_tooltip", 36, objective.max_health},
      jump_limit = objective.upgrades[1],
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 500 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + 2 * objective.upgrades[1])},
        item2 = {name = "copper-plate", tt = "item-name", sprite = "item/copper-plate", count = 1500},
      },
      virtual_cost = {
        virtual1 = {type = "biters", name = Public.tokens.biters.name, tt = "chronosphere", sprite = Public.tokens.biters.sprite, count = 100 * (1 + objective.upgrades[1]^2) * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) }
      }
    },
    [2] = {
      name = {"chronosphere.upgrade_filter"},
      sprite = "recipe/effectivity-module",
      max_level = 9,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_filter_message"},
      tooltip = {"chronosphere.upgrade_filter_tooltip", math_floor(100 * Balance.machine_pollution_transfer_from_inside_factor(Difficulty.get().difficulty_vote_value, objective.upgrades[2]))},
      jump_limit = (1 + objective.upgrades[2]) * 3 or 0,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 5000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "electronic-circuit", tt = "item-name", sprite = "item/electronic-circuit", count = math_min(1 + objective.upgrades[2], 3) * 500 + 500},
        item3 = {name = "advanced-circuit", tt = "item-name", sprite = "item/advanced-circuit", count = math_max(math_min(1 + objective.upgrades[2], 6) - 3, 0) * 500},
        item4 = {name = "processing-unit", tt = "item-name", sprite = "item/processing-unit", count = math_max(math_min(1 + objective.upgrades[2], 9) - 6, 0) * 500}
      },
      virtual_cost = {
        virtual1 = {type = "ecology", name = Public.tokens.ecology.name, tt = "chronosphere", sprite = Public.tokens.ecology.sprite, count = 200 * (1 + objective.upgrades[2] ^ 2)}
      }
    },
    [3] = {
      name = {"chronosphere.upgrade_accumulators"},
      sprite = "recipe/accumulator",
      max_level = 24,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_accumulators_message"},
      tooltip = {"chronosphere.upgrade_accumulators_tooltip"},
      jump_limit = objective.upgrades[3],
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 3000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[3] / 4)},
        item2 = {name = "battery", tt = "item-name", sprite = "item/battery", count = 100 * (1 + objective.upgrades[3])}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 6 * (1 + objective.upgrades[3] / 2)}
      }
    },
    [4] = {
      name = {"chronosphere.upgrade_loot_pickup"},
      sprite = "recipe/long-handed-inserter",
      max_level = 4,
      type = "player",
      enabled = true,
      message = {"chronosphere.upgrade_loot_pickup_message"},
      tooltip = {"chronosphere.upgrade_loot_pickup_tooltip", objective.upgrades[4]},
      jump_limit = 0,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 1000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[4])},
        item2 = {name = "long-handed-inserter", tt = "entity-name", sprite = "recipe/long-handed-inserter", count = 400}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 10 * (1 + objective.upgrades[4])}
      }
    },
    [5] = {
      name = {"chronosphere.upgrade_inventory_size"},
      sprite = "entity/character",
      max_level = 4,
      type = "player",
      enabled = true,
      message = {"chronosphere.upgrade_inventory_size_message"},
      tooltip = {"chronosphere.upgrade_inventory_size_tooltip"},
      jump_limit = (1 + objective.upgrades[5]) * 5,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 2500 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[5])},
        item2 = {name = "wooden-chest", tt = "entity-name", sprite = "item/wooden-chest", count = math_max(0, 250 - math_abs(objective.upgrades[5]) * 250)},
        item3 = {name = "iron-chest", tt = "entity-name", sprite = "item/iron-chest", count = math_max(0, 250 - math_abs(objective.upgrades[5] - 1) * 250)},
        item4 = {name = "steel-chest", tt = "entity-name", sprite = "item/steel-chest", count = math_max(0, 250 - math_abs(objective.upgrades[5] - 2) * 250)},
        item5 = {name = "logistic-chest-storage", tt = "entity-name", sprite = "item/logistic-chest-storage", count = math_max(0, 250 - math_abs(objective.upgrades[5] - 3) * 250)}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 10 * (1 + objective.upgrades[5])}
      }
    },
    [6] = {
      name = {"chronosphere.upgrade_repair"},
      sprite = "recipe/repair-pack",
      max_level = 4,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_repair_message"},
      tooltip = {"chronosphere.upgrade_repair_tooltip", objective.upgrades[6]},
      jump_limit = 0,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 1000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[6])},
        item2 = {name = "repair-pack", tt = "item-name", sprite = "recipe/repair-pack", count = 200 * (1 + objective.upgrades[6])}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 10 * (1 + objective.upgrades[6])}
      }
    },
    [7] = {
      name = {"chronosphere.upgrade_water"},
      sprite = "fluid/water",
      max_level = 1,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_water_message"},
      tooltip = {"chronosphere.upgrade_water_tooltip"},
      jump_limit = 0,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 2000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "pipe", tt = "entity-name", sprite = "item/pipe", count = 500},
        item3 = {name = "pump", tt = "entity-name", sprite = "item/pump", count = 10}
      },
      virtual_cost = {
      }
    },
    [8] = {
      name = {"chronosphere.upgrade_output"},
      sprite = "recipe/cargo-wagon",
      max_level = 2,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_output_message"},
      tooltip = {"chronosphere.upgrade_output_tooltip"},
      jump_limit = 0,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 2000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "fast-inserter", tt = "entity-name", sprite = "recipe/fast-inserter", count = (1 - objective.upgrades[8]) * 200},
        item3 = {name = "constant-combinator", tt = "entity-name", sprite = "recipe/constant-combinator", count = objective.upgrades[8] * 200}
      },
      virtual_cost = {
      }
    },
    [9] = {
      name = {"chronosphere.upgrade_storage"},
      sprite = "item/logistic-chest-storage",
      max_level = 4,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_storage_message"},
      tooltip = {"chronosphere.upgrade_storage_tooltip"},
      jump_limit = (1 + objective.upgrades[9]) * 5,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 3000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[9])},
        item2 = {name = "wooden-chest", tt = "entity-name", sprite = "item/wooden-chest", count = math_max(0, 250 - math_abs(objective.upgrades[9]) * 250)},
        item3 = {name = "iron-chest", tt = "entity-name", sprite = "item/iron-chest", count = math_max(0, 250 - math_abs(objective.upgrades[9] - 1) * 250)},
        item4 = {name = "steel-chest", tt = "entity-name", sprite = "item/steel-chest", count = math_max(0, 250 - math_abs(objective.upgrades[9] - 2) * 250)},
        item5 = {name = "logistic-chest-storage", tt = "entity-name", sprite = "item/logistic-chest-storage", count = math_max(0, 250 - math_abs(objective.upgrades[9] - 3) * 250)}
      },
      virtual_cost = {
      }
    },
    [10] = {
      name = {"chronosphere.upgrade_poison"},
      sprite = "recipe/poison-capsule",
      max_level = 4,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_poison_message"},
      tooltip = {"chronosphere.upgrade_poison_tooltip", math_ceil(objective.poisontimeout/6)},
      jump_limit = 0,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 1000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "poison-capsule", tt = "item-name", sprite = "recipe/poison-capsule", count = 50}
      },
      virtual_cost = {
        virtual1 = {type = "ammo", name = Public.tokens.ammo.name, tt = "chronosphere", sprite = Public.tokens.ammo.sprite, count = 10}
      }
    },
    [11] = {
      name = {"chronosphere.upgrade_fusion"},
      sprite = "recipe/fusion-reactor-equipment",
      max_level = 999,
      type = "player",
      enabled = true,
      message = {"chronosphere.upgrade_fusion_message"},
      tooltip = {"chronosphere.upgrade_fusion_tooltip"},
      jump_limit = 24,
      cost = {
        item1 = {name = "low-density-structure", tt = "item-name", sprite = "item/low-density-structure", count = 70},
        item2 = {name = "processing-unit", tt = "item-name", sprite = "item/processing-unit", count = 50},
        item3 = {name = "solar-panel-equipment", tt = "equipment-name", sprite = "item/solar-panel-equipment", count = 16}
      },
      virtual_cost = {
        virtual1 = {type = "weapons", name = Public.tokens.weapons.name, tt = "chronosphere", sprite = Public.tokens.weapons.sprite, count = 160}
      }
    },
    [12] = {
      name = {"chronosphere.upgrade_mk2"},
      sprite = "recipe/power-armor-mk2",
      max_level = 999,
      type = "player",
      enabled = true,
      message = {"chronosphere.upgrade_mk2_message"},
      tooltip = {"chronosphere.upgrade_mk2_tooltip"},
      jump_limit = 28,
      cost = {
        item1 = {name = "low-density-structure", tt = "item-name", sprite = "item/low-density-structure", count = 100},
        item3 = {name = "power-armor", tt = "item-name", sprite = "item/power-armor", count = 1}
      },
      virtual_cost = {
        virtual1 = {type = "weapons", name = Public.tokens.weapons.name, tt = "chronosphere", sprite = Public.tokens.weapons.sprite, count = 300}
      }
    },
    [13] = {
      name = {"chronosphere.upgrade_computer1"},
      sprite = "item/advanced-circuit",
      max_level = 1,
      type = "quest",
      enabled = true,
      message = {"chronosphere.upgrade_computer1_message"},
      tooltip = {"chronosphere.upgrade_computer1_tooltip"},
      jump_limit = 15,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 5000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "advanced-circuit", tt = "item-name", sprite = "item/advanced-circuit", count = 1000},
        item3 = {name = "copper-plate", tt = "item-name", sprite = "item/copper-plate", count = 2000}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 100}
      }
    },
    [14] = {
      name = {"chronosphere.upgrade_computer2"},
      sprite = "item/processing-unit",
      max_level = 1,
      type = "quest",
      enabled = objective.upgrades[13] == 1,
      message = {"chronosphere.upgrade_computer2_message"},
      tooltip = {"chronosphere.upgrade_computer2_tooltip"},
      jump_limit = 20,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 10000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "processing-unit", tt = "item-name", sprite = "item/processing-unit", count = 1000},
        item3 = {name = "nuclear-reactor", tt = "entity-name", sprite = "item/nuclear-reactor", count = 1}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 200}
      }
    },
    [15] = {
      name = {"chronosphere.upgrade_computer3"},
      sprite = "item/rocket-control-unit",
      max_level = 10,
      type = "quest",
      enabled = objective.upgrades[14] == 1,
      message = {"chronosphere.upgrade_computer3_message", objective.upgrades[15] + 1},
      tooltip = {"chronosphere.upgrade_computer3_tooltip"},
      jump_limit = 25,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 2000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "low-density-structure", tt = "item-name", sprite = "item/low-density-structure", count = 100},
        item3 = {name = "rocket-control-unit", tt = "item-name", sprite = "item/rocket-control-unit", count = 100},
        item4 = {name = "uranium-fuel-cell", tt = "item-name", sprite = "item/uranium-fuel-cell", count = 50}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 30}
      }
    },
    [16] = {
      name = {"chronosphere.upgrade_computer4"},
      sprite = "item/satellite",
      max_level = 1,
      type = "quest",
      enabled = objective.upgrades[15] == 10,
      message = {"chronosphere.upgrade_computer4_message"},
      tooltip = {"chronosphere.upgrade_computer4_tooltip"},
      jump_limit = 25,
      cost = {
        item1 = {name = "rocket-silo", tt = "entity-name", sprite = "item/rocket-silo", count = 1},
        item2 = {name = "satellite", tt = "item-name", sprite = "item/satellite", count = 1},
        item3 = {name = "spidertron", tt = "entity-name", sprite = "item/spidertron", count = 2}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 400}
      }
    },
    [17] = {
      name = {"chronosphere.upgrade_nukeshied"},
      sprite = "item/rocket",
      max_level = 1,
      type = "quest",
      enabled = objective.upgrades[17] == 1 or (objective.world.id == 2 and objective.world.variant.id == 2),
      message = {"chronosphere.upgrade_nukeshield_message"},
      tooltip = {"chronosphere.upgrade_nukeshield_tooltip"},
      jump_limit = 0,
      cost = {
        item1 = {name = "rocket", tt = "item-name", sprite = "item/rocket", count = 1000},
        item2 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 10000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)}
      },
      virtual_cost = {
        virtual1 = {type = "ammo", name = Public.tokens.ammo.name, tt = "chronosphere", sprite = Public.tokens.ammo.sprite, count = 200},
        virtual2 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 40},

      }
    },
    [18] = {
      name = {"chronosphere.upgrade_researchspeed"},
      sprite = "item/lab",
      max_level = 4,
      type = "quest",
      enabled = objective.chronojumps >= 7,
      message = {"chronosphere.upgrade_researchspeed_message"},
      tooltip = {"chronosphere.upgrade_researchspeed_tooltip"},
      jump_limit = (1 + objective.upgrades[18]) * 6,
      cost = {
        item1 = {name = "lab", tt = "item-name", sprite = "item/lab", count = 50 * (1 + objective.upgrades[18])},
        item2 = {name = "speed-module", tt = "item-name", sprite = "item/speed-module", count = 20 * (1 + objective.upgrades[18])},
        item3 = {name = "productivity-module", tt = "item-name", sprite = "item/productivity-module", count = 20 * (1 + objective.upgrades[18])},
        item4 = {name = "speed-module-2", tt = "item-name", sprite = "item/speed-module-2", count = 20 * (objective.upgrades[18] / 2)}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 200},
      }
    },
    [19] = {
      name = {"chronosphere.upgrade_craftingspeed"},
      sprite = "item/assembling-machine-1",
      max_level = 4,
      type = "player",
      enabled = true,
      message = {"chronosphere.upgrade_craftingspeed_message"},
      tooltip = {"chronosphere.upgrade_craftingspeed_tooltip"},
      jump_limit = (1 + objective.upgrades[19]) * 5,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 1000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[19])},
        item2 = {name = "assembling-machine-1", tt = "entity-name", sprite = "item/assembling-machine-1", count = 50 * (1 + objective.upgrades[19])},
        item3 = {name = "assembling-machine-2", tt = "entity-name", sprite = "item/assembling-machine-2", count = 50 * (objective.upgrades[19])}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 10 * (1 + objective.upgrades[19])},
      }
    },
    [20] = {
      name = {"chronosphere.upgrade_discharge"},
      sprite = "item/discharge-defense-equipment",
      max_level = 5,
      type = "player",
      enabled = true,
      message = {"chronosphere.upgrade_discharge_message"},
      tooltip = {"chronosphere.upgrade_discharge_tooltip"},
      jump_limit = 5 + (1 + objective.upgrades[20]) * 8,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 5000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[20])},
        item2 = {name = "discharge-defense-equipment", tt = "equipment-name", sprite = "item/discharge-defense-equipment", count = 2 * (1 + objective.upgrades[20])},
      },
      virtual_cost = {
        virtual1 = {type = "ammo", name = Public.tokens.ammo.name, tt = "chronosphere", sprite = Public.tokens.ammo.sprite, count = 50 * (1 + objective.upgrades[20])},
        virtual2 = {type = "biters", name = Public.tokens.biters.name, tt = "chronosphere", sprite = Public.tokens.biters.sprite, count = 8000 * (1 + objective.upgrades[20])^2},
      }
    },
    [21] = {
      name = {"chronosphere.upgrade_spidertron"},
      sprite = "recipe/spidertron",
      max_level = 2,
      type = "quest",
      enabled = objective.upgrades[15] == 10 and Difficulty.get().difficulty_vote_value >= 1,
      message = {"chronosphere.upgrade_spidertron_message", objective.upgrades[21] + 1},
      tooltip = {"chronosphere.upgrade_spidertron_tooltip"},
      jump_limit = 20,
      cost = {
        item1 = {name = "automation-science-pack", tt = "item-name", sprite = "item/automation-science-pack", count = (1 - objective.upgrades[21]) * 3000},
        item2 = {name = "logistic-science-pack", tt = "item-name", sprite = "item/logistic-science-pack", count = (1 - objective.upgrades[21]) * 3000},
        item3 = {name = "military-science-pack", tt = "item-name", sprite = "item/military-science-pack", count = (1 - objective.upgrades[21]) * 2400},
        item4 = {name = "chemical-science-pack", tt = "item-name", sprite = "item/chemical-science-pack", count = objective.upgrades[21] * 1250},
        item5 = {name = "production-science-pack", tt = "item-name", sprite = "item/production-science-pack", count = objective.upgrades[21] * 1250},
        item6 = {name = "utility-science-pack", tt = "item-name", sprite = "item/utility-science-pack", count = objective.upgrades[21] * 1250},
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 100},
      }
    },
    [22] = {
      name = {"chronosphere.upgrade_train_lasers"},
      sprite = "item/personal-laser-defense-equipment",
      max_level = 4,
      type = "train",
      enabled = true,
      message = {"chronosphere.upgrade_train_lasers_message"},
      tooltip = {"chronosphere.upgrade_train_lasers_tooltip"},
      jump_limit = (2 + objective.upgrades[22]) * 5,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 5000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty) * (1 + objective.upgrades[22])},
        item2 = {name = "laser-turret", tt = "item-name", sprite = "item/laser-turret", count = 25 * (1 + objective.upgrades[22])},
        item3 = {name = "accumulator", tt = "entity-name", sprite = "item/accumulator", count = 25 * (1 + objective.upgrades[22])},
      },
      virtual_cost = {
        virtual1 = {type = "ammo", name = Public.tokens.ammo.name, tt = "chronosphere", sprite = Public.tokens.ammo.sprite, count = 20 * (1 + objective.upgrades[22])},
        virtual2 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 10 * (1 + objective.upgrades[22])},
      }
    },
    [23] = {
      name = {"chronosphere.upgrade_nuclear_artillery"},
      sprite = "recipe/artillery-turret",
      max_level = 1,
      type = "quest",
      enabled = objective.upgrades[15] == 10 and game.forces.player.technologies["artillery"].researched == true,
      message = {"chronosphere.upgrade_nuclear_artillery_message"},
      tooltip = {"chronosphere.upgrade_nuclear_artillery_tooltip"},
      jump_limit = 20,
      cost = {
        item1 = {name = "coin", tt = "item-name", sprite = "item/coin", count = 10000 * Balance.upgrades_coin_cost_difficulty_scaling(difficulty)},
        item2 = {name = "artillery-turret", tt = "entity-name", sprite = "item/artillery-turret", count = 10},
        item3 = {name = "military-science-pack", tt = "item-name", sprite = "item/military-science-pack", count = 1000},
        item4 = {name = "atomic-bomb", tt = "item-name", sprite = "item/atomic-bomb", count = 20},
        item5 = {name = "rocket-control-unit", tt = "item-name", sprite = "item/rocket-control-unit", count = 50},
        item6 = {name = "satellite", tt = "item-name", sprite = "item/satellite", count = 1}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 200}
      }
    },
    [24] = {
      name = {"chronosphere.upgrade_nuclear_artillery_ammo"},
      sprite = "item/atomic-bomb",
      max_level = 100,
      type = "quest",
      enabled = objective.upgrades[23] == 1,
      message = {"chronosphere.upgrade_nuclear_artillery_ammo_message"},
      tooltip = {"chronosphere.upgrade_nuclear_artillery_ammo_tooltip"},
      jump_limit = 20,
      cost = {
        item1 = {name = "atomic-bomb", tt = "item-name", sprite = "item/atomic-bomb", count = 10},
      },
      virtual_cost = {
        virtual1 = {type = "biters", name = Public.tokens.biters.name, tt = "chronosphere", sprite = Public.tokens.biters.sprite, count = 500}
      }
    },
    [25] = {
      name = {"chronosphere.upgrade_poison_mastery"},
      sprite = "item/heavy-armor",
      max_level = 4,
      type = "quest",
      enabled = objective.poison_mastery_unlocked >= 10,
      message = {"chronosphere.upgrade_poison_mastery_message"},
      tooltip = {"chronosphere.upgrade_poison_mastery_tooltip"},
      jump_limit = 0,
      cost = {
        item1 = {name = "heavy-armor", tt = "item-name", sprite = "item/heavy-armor", count = 10},
        item2 = {name = "power-armor", tt = "item-name", sprite = "item/power-armor", count = (1 + objective.upgrades[25])},
        item3 = {name = "poison-capsule", tt = "item-name", sprite = "recipe/poison-capsule", count = 50 * (1 + objective.upgrades[25])},
        item4 = {name = "military-science-pack", tt = "item-name", sprite = "item/military-science-pack", count = (1 + objective.upgrades[25]) * 100},
        item5 = {name = "chemical-science-pack", tt = "item-name", sprite = "item/chemical-science-pack", count = objective.upgrades[25] * 100}
      },
      virtual_cost = {
        virtual1 = {type = "tech", name = Public.tokens.tech.name, tt = "chronosphere", sprite = Public.tokens.tech.sprite, count = 20 * (1 + objective.upgrades[25])},
        virtual2 = {type = "ammo", name = Public.tokens.ammo.name, tt = "chronosphere", sprite = Public.tokens.ammo.sprite, count = 10 * (1 + objective.upgrades[25])}
      }
    }

    --don't forget to change the count in count function on top after adding more upgrades!

  }
  return upgrades
end

return Public