-- TE4 - T-Engine 4
-- Copyright (C) 2009 - 2018 Nicolas Casalini
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program.  If not, see <http://www.gnu.org/licenses/>.
--
-- Nicolas Casalini "DarkGod"
-- darkgod@te4.org

require "engine.class"
local Entity = require "engine.Entity"
local Dialog = require "engine.ui.Dialog"
local Inventory = require "engine.interface.ActorInventory"
local ShowStore = require_first("mod.dialogs.ShowStore", "engine.dialogs.ShowStore")
local GetQuantity = require "engine.dialogs.GetQuantity"

--- Store
-- @classmod engine.Store
module(..., package.seeall, class.inherit(Entity, Inventory))

function _M:init(t, no_default)
	self.allow_sell = true
	self.allow_buy = true
	t = t or {}

	t.body = {INVEN=10000}

	Entity.init(self, t, no_default)
	Inventory.init(self, t, no_default)
end

--- Default restock checking method
-- Checks based on turns elapsed, you may overload it to do your own checks
function _M:canRestock()
	local s = self.store
	if self.last_filled and game.turn and self.last_filled >= game.turn - s.restock_after then
		print("[STORE] not restocking yet", game.turn, s.restock_after, self.last_filled)
		return false
	end
	return true
end

--- Checks if the given entity is allowed
function _M:allowStockObject(e)
	return true
end

--- Fill the store with goods
-- @param level the level to generate for (instance of type engine.Level)
-- @param zone the zone to generate for
-- @param force_nb[opt] make it generate a specific number of items
function _M:loadup(level, zone, force_nb)
	local s = self.store
	if not s then error("Store without a store field") end
	if not self:canRestock() then return end
	local inven = self:getInven("INVEN")

	for i = #inven, 1, -1 do
		local e = inven[i]
		if (s.empty_before_restock and not e.__store_forget) or (e.__force_store_forget) then
			table.remove(inven, i)
			e:removed()
		end
	end

	local i = 1
	local rngfill = force_nb or (rng.range(s.min_fill, s.max_fill) - #inven)
	while i <= rngfill do
		local filter = util.getval(s.filters)
		if not filter then break end
		filter = table.clone(filter)
		local e
		if not filter.defined then e = zone:makeEntity(level, "object", filter, nil, true)
		else e = zone:makeEntityByName(level, "object", filter.defined) end
		if e and not e.not_in_stores and self:allowStockObject(e) then
			if s.post_filter and not s.post_filter(e) then
			else
				if filter.id then e:identify(filter.id) end
				self:addObject(inven, e)
				zone:addEntity(level, e, "object")
				self:check("stocked_object", e)
				print("[STORE] stocking up: ", e.name)
				i = i + 1
			end
		elseif not e then
			i = i + 1
		end
	end

	for i = 1, #(s.fixed or {}) do
		local filter = table.clone(s.fixed[i])
		local e
		if not filter.defined then e = zone:makeEntity(level, "object", filter, nil, true)
		else e = zone:makeEntityByName(level, "object", filter.defined) end
		if e and not e.not_in_stores and self:allowStockObject(e) then
			if filter.id then e:identify(filter.id) end
			self:addObject(inven, e)
			zone:addEntity(level, e, "object")
			self:check("stocked_object", e)
			print("[STORE] stocking up: ", e.name)
		end
	end

	self:sortInven(inven)
	self.last_filled = game.turn
	return true
end

--- Actor interacts with the store
-- @param who the actor who interacts
-- @param[opt] name display name of the store
function _M:interact(who, name)
	local store, inven = self:getInven("INVEN"), who:getInven("INVEN")
	local d; d = ShowStore.new("Store: "..(name or self.name), store, inven, self.store.store_filter, self.store.actor_filter, function(what, o, item)
		if what == "buy" then
			if o:getNumber() > 1 then
				local q = GetQuantity.new(nil, nil, o:getNumber(), o:getNumber(), function(qty) self:doBuy(who, o, item, qty, d) end)
				game:registerDialog(q)
			else
				self:doBuy(who, o, item, 1, d)
			end
		else
			if o:getNumber() > 1 then
				local q
				q = GetQuantity.new(nil, nil, o:getNumber(), o:getNumber(), function(qty) self:doSell(who, o, item, qty, d) end)
				game:registerDialog(q)
			else
				self:doSell(who, o, item, 1, d)
			end
		end
	end, function(what, o)
		return self:descObject(who, what, o)
	end, function(what, o)
		return self:descObjectPrice(who, what, o)
	end, self.allow_sell, self.allow_buy, function(item) end, self, who)
	game:registerDialog(d)
end

function _M:transfer(src, dest, item, nb)
	local src_inven, dest_inven = src:getInven("INVEN"), dest:getInven("INVEN")
	for i = 1, nb do
		local o = src:removeObject(src_inven, item)
		dest:addObject(dest_inven, o)
	end
	src:sortInven(src_inven)
	dest:sortInven(dest_inven)
end

--- assumes buyer has room
function _M:doBuy(who, o, item, nb, store_dialog)
	nb = math.min(nb, o:getNumber())
	nb = self:tryBuy(who, o, item, nb)
	if nb then
		Dialog:yesnoPopup("Buy", ("Buy %d %s"):format(nb, o:getName{do_color=true, no_count=true}), function(ok) if ok then
			self:onBuy(who, o, item, nb, true)
			self:transfer(self, who, item, nb)
			self:onBuy(who, o, item, nb, false)
			if store_dialog then store_dialog:updateStore() end
		end end, "Buy", "Cancel")
	end
end

function _M:doSell(who, o, item, nb, store_dialog)
	nb = math.min(nb, o:getNumber())
	nb = self:trySell(who, o, item, nb)
	if nb then
		Dialog:yesnoPopup("Sell", ("Sell %d %s"):format(nb, o:getName{do_color=true, no_count=true}), function(ok) if ok then
			self:onSell(who, o, item, nb, true)
			self:transfer(who, self, item, nb)
			self:onSell(who, o, item, nb, false)
			if store_dialog then store_dialog:updateStore() end
		end end, "Sell", "Cancel")
	end
end

--- Called on object purchase try
-- @param who the actor buying
-- @param o the object trying to be purchased
-- @param item the index in the inventory
-- @param nb number of items (if stacked) to buy
-- @return a number (or nil) if allowed to buy, giving the number of objects to buy
function _M:tryBuy(who, o, item, nb)
	return nb
end

--- Called on object sale try
-- @param who the actor selling
-- @param o the object trying to be sold
-- @param item the index in the inventory
-- @param nb number of items (if stacked) to sell
-- @return a number (or nil) if allowed to sell, giving the number of objects to sell
function _M:trySell(who, o, item, nb)
	return nb
end


--- Called on object purchase
-- @param who the actor buying
-- @param o the object trying to be purchased
-- @param item the index in the inventory
-- @param nb number of items (if stacked) to buy
-- @param before true if this happens before removing the item
function _M:onBuy(who, o, item, nb, before)
end

--- Called on object sale
-- @param who the actor selling
-- @param o the object trying to be sold
-- @param item the index in the inventory
-- @param nb number of items (if stacked) to sell
-- @param before true if this happens before removing the item
function _M:onSell(who, o, item, nb, before)
end

--- Called to describe an object, being to sell or to buy
-- @param who the actor
-- @param what either "sell" or "buy"
-- @param o the object
-- @return a string (possibly multiline) describing the object
function _M:descObject(who, what, o)
	return o:getDesc()
end

--- Called to describe an object's price, being to sell or to buy
-- @param who the actor
-- @param what either "sell" or "buy"
-- @param o the object
-- @return a string describing the price
function _M:descObjectPrice(who, what, o)
	return ""
end