116 lines
4.7 KiB
Lua
116 lines
4.7 KiB
Lua
-- Gold economy: a price catalog for tradeable goods plus the buy/sell math for
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-- a shopkeeper's wares. Wares seeded on the floor by the builder carry a
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-- `price` and `shopId` tag on the ground entry (not the item), so a purchased
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-- item is indistinguishable from a found one once it reaches the inventory.
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local Items = require("items")
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local Affixes = require("affixes")
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local Factions = require("factions")
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local Mercenaries = require("mercenaries")
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local Shop = {}
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local POTION_PRICE = {
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heal = 15, poison = 6, strength = 45, haste = 25, clarity = 20, cure = 30,
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confuse = 8, blind = 8, levitate = 20,
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}
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local SCROLL_PRICE = { teleport = 25, identify = 18, mapping = 20, fireball = 35 }
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local FLAT_PRICE = { [Items.FOOD] = 5, [Items.TOME] = 55, [Items.PICK] = 40 }
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local AMMO_UNIT_PRICE = 2
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-- Catalog price for any tradeable item. Gear scales with its effective power
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-- or bonuses so a heavily-affixed drop costs more than a plain one.
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function Shop.priceOf(item)
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if item.kind == Items.POTION then
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return POTION_PRICE[item.effect] or 10
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elseif item.kind == Items.SCROLL then
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return SCROLL_PRICE[item.effect] or 10
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elseif item.kind == Items.WEAPON or item.kind == Items.ARMOR then
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return 20 + item.power * 15
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elseif item.kind == Items.BOW then
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return 25 + item.power * 12
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elseif item.kind == Items.RING then
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return 30 + (item.attack + item.defense) * 20
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elseif item.kind == Items.AMMO then
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return AMMO_UNIT_PRICE * (item.count or 1)
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elseif item.kind == Items.CONTRACT then
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return Mercenaries.byKey[item.hireling].hireCost
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else
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return FLAT_PRICE[item.kind] or 10
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end
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end
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function Shop.sellValue(item)
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return math.max(1, Shop.priceOf(item) // 2)
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end
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-- The price a shopkeeper actually charges once the player's standing with
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-- the merchant guild (see factions.lua) has had its say: sour relations mark
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-- goods up, warm ones discount them. `ground.price` (stamped once at
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-- generation - see builder.lua) stays the neutral catalog price throughout,
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-- so it keeps meaning "what a stranger pays" even as this moves the amount
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-- actually charged.
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function Shop.effectivePrice(game, ground)
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return math.max(1, math.floor(ground.price * Factions.priceMultiplier(game.player, Factions.MERCHANT)))
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end
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-- Buys a warded ground item if the player can afford its reputation-adjusted
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-- price: deducts gold and transfers the item into the inventory. Returns the
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-- gold actually spent, or nil without side effects when the player is short.
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function Shop.buy(game, ground)
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if not ground.price then return nil end
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local price = Shop.effectivePrice(game, ground)
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if game.player.gold < price then return nil end
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game.player.gold = game.player.gold - price
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game.player.inventory[#game.player.inventory + 1] = ground.item
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return price
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end
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-- Sells an inventory item at half its catalog price (further scaled by
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-- merchant standing) and removes it.
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function Shop.sell(game, index)
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local item = game.player.inventory[index]
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if not item then return nil end
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local value = math.max(1, math.floor(Shop.sellValue(item) / Factions.priceMultiplier(game.player, Factions.MERCHANT)))
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game.player.gold = game.player.gold + value
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table.remove(game.player.inventory, index)
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return value
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end
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local weaponBases = { { name = "rapier", power = 3 }, { name = "war hammer", power = 5 } }
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local armorBases = { { name = "banded mail", power = 2 } }
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-- Rolls a small selection of wares for a shop room. Weapons and armour may
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-- still carry an affix, so the shop is a genuine alternative to a lucky drop
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-- rather than a strictly worse copy of one.
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function Shop.stock(rng)
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local wares = {}
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local slots = rng:range(3, 5)
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for _ = 1, slots do
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local roll = rng:range(1, 100)
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local item
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if roll <= 30 then
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local effects = { "heal", "strength", "haste", "clarity", "cure" }
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item = Items.potionOf(effects[rng:range(1, #effects)])
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elseif roll <= 45 then
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local effects = { "identify", "mapping", "fireball" }
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item = Items.scroll(effects[rng:range(1, #effects)])
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elseif roll <= 62 then
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local base = weaponBases[rng:range(1, #weaponBases)]
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item = Affixes.decorate(Items.weapon(base.name, base.power), Affixes.rollWeapon(rng))
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elseif roll <= 75 then
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local base = armorBases[rng:range(1, #armorBases)]
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item = Affixes.decorate(Items.armor(base.name, base.power), Affixes.rollArmor(rng))
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elseif roll <= 85 then
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item = Items.ring("ring of the merchant", rng:range(0, 2), rng:range(0, 2))
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else
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local key = Mercenaries.order[rng:range(1, #Mercenaries.order)]
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item = Items.contract(key, "contract: hire the " .. Mercenaries.byKey[key].name)
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end
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wares[#wares + 1] = item
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end
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return wares
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end
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return Shop
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