Module:Sandbox/Combat

Documentation for this module may be created at Module:Sandbox/Combat/doc

-- **
-- Damage calculations are based on http://kancollecalc.web.fc2.com/damage_formula.html and WikiWiki combat page.
-- NB CI rate formula is from WikiWiki combat page (also, 検証、仮説スレ18).
-- 

local Combat = {}

-- * Experimental values.

Combat.modifier = {

	comined_firepower = {
		ctf_first = 0,
		ctf_second = 10,
		stf_first = 10,
		stf_second = -5,
	},

	comined_torpedo = -5,

	night_contact = 5,

	formation = {
		line_ahead = 1.0,
		double_line = 0.8,
		diamond = 0.7,
		echelon = 0.6,
		line_abreast = 0.6,
		combined = {
			line_ahead = 1.1,
			diamond = 0.7,
			double_line = 1.0,
			line_abreast = 0.8,
		},
	},

	engagement = {
		green_t = 1.2,
		parallel = 1.0,
		head_on = 0.8,
		red_t = 0.6,
	},

	health = {
		normal = 1.0,
		chuuha = 0.7,
		taiha = 0.4,
	},

	anti_ground = 2.5,
	wg_bonus = 75,

	cap = {
		day = 150,
		night = 300,
	},

	spotting = {
		cut_in = {
			main_main = 1.5,
			main_ap = 1.3,
			main_radar = 1.2,
			main_second = 1.1,
		},
		double = 1.2,
	},

	night_attack = {
		cut_in = {
			main = 2,
			main_misc = 1.75,
			torpedo = 1.5,
			mixed = 1.3,
		},
		double = 1.2,
		normal = 1,
	},

	critical = 1.5,

	ap = {
		main_ap = 1.08,
		main_ap_radar = 1.1,
		main_second_ap = 1.15,
		main_second_ap_radar = 1.15,
	},

}

function Combat.ammo_modifier(ammo_bars)
	return ammo_bars >= 5 and 1 or ammo_bars / 5
end

-- * Combat object with ship-independent values as fields.
--   Ship and enemy values are passed via arguments.

function Combat:new(is_night_battle)
	local stage = {
		combined_firepower = 0,
		combined_torpedo = 0,
		formation = self.modifier.formation.line_ahead,
		engagement = self.modifier.engagement.parallel,
		night_contact = 0,
		is_night_battle = is_night_battle,
		cap = is_night_battle and self.modifier.cap.night or self.modifier.cap.day,
		contact = 1, -- TODO
		expert = 1, -- TODO
	}
	setmetatable(stage, self)
	self.__index = self
	return stage
end

function Combat:damage_pre_cap(ship)
	return self.engagement * self.formation * ship.health * ship.anti_ground * ship.anti_sub * ship.night_attack * ship.attack_power
end

function Combat:damage_cap(attack_power)
	if attack_power > self.cap then
		attack_power = self.cap + math.sqrt(attack_power - self.cap)
	end
	return math.floor(attack_power)
end

function Combat:damage_post_cap(attack_power, ship, enemy_armor)
	attack_power = ship.spotting * self.contact * math.floor(self.expert * ship.critical * math.floor(ship.ap * attack_power))
	-- Use a note on a caller side instead
	--if ship.night_attack_x2 then
	--	attack_power = 2 * attack_power
	--end
	if enemy_armor then
		local min_armor = enemy_armor * 0.7
		local max_armor = enemy_armor * 0.7 + math.max(enemy_armor - 1, 0) * 0.6
		local min = math.floor((attack_power - max_armor) * ship.ammo)
		local max = math.floor((attack_power - min_armor) * ship.ammo)
		return { min, max }
	else
		return math.floor(attack_power * ship.ammo)
	end
end

-- TODO: pass enemy table, do additional detection (e.g. torpedo = 0 vs. ground type enemies
-- or attack_power = 0 when BB vs. enemy submarines, etc.)
function Combat:damage(ship, enemy_armor)
	return self:damage_post_cap(self:damage_cap(self:damage_pre_cap(ship)), ship, enemy_armor)
end

-- TODO: carrier shelling, aerial, ASW, support expedition.

Combat.nb_cut_in_types = {
	torpedo = { k = 70, luck_cap = 60 },
	mixed = { k = 70, luck_cap = 70 },
	main = { k = 50, luck_cap = 55 },
}

function Combat.nb_cut_in_rate(ship, modifier)
	if ship._luck <= modifier.luck_cap then
		return math.floor(math.sqrt(modifier.k * ship._luck))
	else
		return Combat.nb_cut_in_rate(modifier.luck_cap, modifier)
	end
end

function Combat:shelling(ship)
	ship.attack_power = 5 + ship._firepower_max + ship.equipment_bonus.firepower + self.combined_firepower + ship.anti_ground_bonus
	return ship
end

function Combat:torpedo(ship)
	ship.attack_power = 5 + ship._torpedo_max + ship.equipment_bonus.torpedo + self.combined_torpedo
	return ship
end

function Combat:night_battle(ship)
	if ship.health == self.modifier.health.taiha then
		ship.attack_power = 0
	else
		ship.attack_power = self.night_contact + ship._firepower_max + ship._torpedo_max + ship.equipment_bonus.firepower + ship.equipment_bonus.torpedo
	end
	return ship
end

-- * Ship object with extra fields related to combat.

local Ship = {}

function Ship:new(ship, equip, night_attack, spotting)

	self._firepower_max = ship._firepower_max or 0
	self._torpedo_max = ship._torpedo_max or 0
	self._luck = ship._luck or 0

	self.equipment = equip or {}
	self.equipment_bonus = { firepower = 0, torpedo = 0 }
	for _, eq in pairs(self.equipment) do
		if eq.firepower then
			self.equipment_bonus.firepower = self.equipment_bonus.firepower + eq.firepower + (eq.k and eq.rank and eq.k * math.sqrt(eq.rank) or 0)
		end
		if eq.torpedo then
			self.equipment_bonus.torpedo = self.equipment_bonus.torpedo + eq.torpedo + (eq.k and eq.rank and eq.k * math.sqrt(eq.rank) or 0)
		end
	end
	self.equipment_bonus.firepower = math.floor(self.equipment_bonus.firepower)
	self.equipment_bonus.torpedo = math.floor(self.equipment_bonus.torpedo)

	self.health = ship.health or Combat.modifier.health.normal
	self.anti_ground = ship.anti_ground and Combat.modifier.anti_ground or 1
	self.anti_ground_bonus = ship.wg and Combat.modifier.wg_bonus or 0
	self.anti_sub = ship.anti_sub or 1
	self.night_attack = night_attack or 1
	self.night_attack_x2 = night_attack == Combat.modifier.night_attack.cut_in.torpedo or
						   night_attack == Combat.modifier.night_attack.cut_in.mixed
	self.spotting = spotting or 1
	self.critical = ship.critical or 1
	self.ap = ship.ap or 1
	self.ammo = ship.ammo or 1
	return self

end