-- Core functions for corruptions

__corruptions = {}
__corruptions_max = 0
__corruptions_callbacks_max = 0

-- Get the corruption
function player.corruption(c, set)
	if set then
		player.corruptions_aux[c + 1] = set
		player.redraw = bor(player.redraw, PR_BASIC)
		player.update = bor(player.update, PU_BONUS, PU_TORCH, PU_BODY, PU_POWERS)
		if (set == TRUE) and (__corruptions[c].gain) then
			__corruptions[c].gain()
		end
		if (set == FALSE) and (__corruptions[c].lose) then
			__corruptions[c].lose()
		end
	else
		return player.corruptions_aux[c + 1]
	end
end

-- Test if we have that corruption
-- We must:
-- 1) have it or be willing to get it
-- 2) have all its dependancies
-- 3) have none of its opposing corruptions
-- 4) pass the possible tests
function test_depend_corrupt(corrupt, can_gain)
	local i, c

	if not can_gain then can_gain = FALSE end

	if can_gain == TRUE then
		if (player.corruption(corrupt) ~= FALSE) then
			return FALSE
		end
	else
		if (player.corruption(corrupt) ~= TRUE) then
			return FALSE
		end
	end

	for c, i in __corruptions[corrupt].depends do
		if test_depend_corrupt(c) ~= TRUE then
			return FALSE
		end
	end

	for c, i in __corruptions[corrupt].oppose do
		if test_depend_corrupt(c) ~= FALSE then
			return FALSE
		end
	end

	-- are we even allowed to get it?
	return player_can_gain_corruption(corrupt)
end

-- Gain a new corruption
function gain_corruption(group)
	local i, max
	local pos = {}

	-- Get the list of all possible ones
	max = 0
	for i = 0, __corruptions_max - 1 do
		if __corruptions[i].group == group and test_depend_corrupt(i, TRUE) == TRUE and __corruptions[i].random == TRUE and __corruptions[i].allow() then
			pos[max] = i
			max = max + 1
		end
	end

	-- Ok now get one of them
	if (max > 0) then
		local ret = rand_int(max)

		player.corruption(pos[ret], TRUE)
		cmsg_print(TERM_L_RED, __corruptions[pos[ret]].get_text)

		return pos[ret]
	else
		return -1
	end
end

-- Lose an existing corruption
function lose_corruption()
	local i, max
	local pos = {}

	-- Get the list of all possible ones
	max = 0
	for i = 0, __corruptions_max - 1 do
		if test_depend_corrupt(i) == TRUE and __corruptions[i].removable == TRUE then
			pos[max] = i
			max = max + 1
		end
	end

	-- Ok now get one of them
	if (max > 0) then
		local ret = rand_int(max)

		player.corruption(pos[ret], FALSE)
		cmsg_print(TERM_L_RED, __corruptions[pos[ret]].lose_text)

		-- Ok now lets see if it broke some dependancies
		for i = 0, max - 1 do
			if player.corruption(pos[i]) ~= test_depend_corrupt(pos[i]) then
				player.corruption(pos[i], FALSE)
				cmsg_print(TERM_L_RED, __corruptions[pos[i]].lose_text)
			end
		end

		return pos[ret]
	else
		return -1
	end
end

-- Lose all corruptions (for e.g. Potion of New Life)
function lose_all_corruptions()
	local i;
	for i = 0, __corruptions_max - 1 do
		lose_corruption()
	end
	return -1
end

-- Creates a new corruption
function add_corruption(c)
	assert(c.color, "No corruption color")
	assert(c.name, "No corruption name")
	assert(c.get_text, "No corruption get_text")
	assert(c.lose_text, "No corruption lose_text")
	assert(c.desc, "No corruption desc")
	if not c.random then c.random = TRUE end
	if not c.removable then c.removable = TRUE end
	if not c.allow then c.allow = function() return not nil end end

	if c.depends == nil then c.depends = {} end
	if c.oppose == nil then c.oppose = {} end

	-- We must make sure the other ones opposes too
	local o, i
	for o, i in c.oppose do
		__corruptions[o].oppose[__corruptions_max] = TRUE
	end

	local index, h
        if type(c.hooks) == "table" then
		for index, h in c.hooks do
			add_hook_script(index, "__lua__corrupt_callback"..__corruptions_callbacks_max, "__lua__corrupt_callback"..__corruptions_callbacks_max)
			setglobal("__lua__corrupt_callback"..__corruptions_callbacks_max,
				function (...)
					if test_depend_corrupt(%__corruptions_max) == TRUE then
						return call(%h, arg)
					end
				end
			)
			__corruptions_callbacks_max = __corruptions_callbacks_max + 1
		end
	end

	if type(c.desc) == "table" then
		local new_desc = ""
		for index, h in c.desc do
			new_desc = new_desc..h.."\n"
		end
		c.desc = new_desc
	end

	__corruptions[__corruptions_max] = c
	__corruptions_max = __corruptions_max + 1
	return (__corruptions_max - 1)
end