-- lootoverlay.lua — speak what the game's loot highlight shows.
--
-- The tutorial says: "Press 's' to see the contents of containers." For a
-- sighted player that turns on `levelWindow.itemsHighlightEnabled`, which draws
-- the icon of the topmost item of every visible container or pile straight onto
-- the map. By ear it did nothing at all — so the one mechanic the game
-- explicitly teaches for finding reagents was unusable, and alchemy starts with
-- finding reagents.
--
-- This announces the same thing in words, and goes one better: the overlay can
-- only draw ONE icon per tile, so it tells a sighted player "there is something
-- in that chest" but not what. We read the whole `tile.loot` list.
--
--------------------------------------------------------------------------------
-- Why this is polled rather than key-bound
--------------------------------------------------------------------------------
--
-- `s` is a game-claimed scancode, and keybindings.getCommand() dispatches on
-- scancode ignoring modifiers, so binding anything on it in our layer would
-- either eat the game's own command or fire alongside a modifier we don't want.
-- Instead we watch `levelWindow.itemsHighlightEnabled` and speak on its rising
-- edge. That is the single flag both `lootOverlayClick` and its mouse-button
-- twin set, so this covers:
--
--   * the key, in hold mode (config `holdForItemHighlight`) and in toggle mode,
--   * clicking the toolbar icon,
--   * `ingame`, `ingame_observe` and both targeting states, which all share the
--     one levelWindow instance (it is created once in ingame.open and passed on
--     through params).
--
-- No game file is touched, and the player's own key stays whatever they have
-- rebound it to.
--
--------------------------------------------------------------------------------
-- FoV
--------------------------------------------------------------------------------
--
-- Membership matches levelWindow's own test exactly: current `FoV` only (not
-- rememberedFoV), tile not hidden, `visibilityAlpha ~= 0`, loot list non-empty.
-- Nothing is reported that is not being drawn on screen at that moment.

local speech = require("accessibility.speech")
local describe = require("accessibility.describe")
local history = require("accessibility.history")
local menus = require("accessibility.menus")

local lootoverlay = {}

local config = {
	-- Half-width of the scanned box around the player, in tiles. Sight range is
	-- well inside this; the overlay itself only draws within the camera view.
	radius = 20,

	-- Longest utterance worth producing in one go. A warehouse floor covered in
	-- piles would otherwise read for a minute with no way to stop partway.
	maxTiles = 12,
}

lootoverlay.config = config

local wasEnabled = false

--------------------------------------------------------------------------------
-- Reading the level
--------------------------------------------------------------------------------

local function getLevel()
	local ok, world = pcall(require, "models.world")
	if not ok or not world.currentLevel then
		return nil
	end
	return world.currentLevel
end

local function itemTemplates()
	local ok, templates = pcall(require, "modules.item.templates")
	return ok and templates or nil
end

-- Loot entries are item *parameters* ({templateId, quantity}), not constructed
-- items — modules/lootPopup.lua builds real items from them only when the popup
-- opens. So the name comes from the template, and constructing an item here
-- (which allocates canvases) is avoided.
local function itemText(entry, templates)
	if type(entry) ~= "table" then
		return nil
	end

	local template = entry.templateId and templates and templates[entry.templateId]
	local name = (template and template.name) or entry.name or entry.templateId

	if not name then
		return nil
	end

	local quantity = tonumber(entry.quantity) or 1

	-- Quantities can be fractional (distilling yields x0.2), and floatfix leaves
	-- long tails behind. Two decimals is what the game's own quantity label shows.
	quantity = math.floor(quantity * 100 + 0.5) / 100

	if quantity == 1 then
		return tostring(name)
	end

	return tostring(name) .. ", " .. tostring(quantity)
end

-- The tiles the overlay is drawing an icon on, nearest first.
-- Each entry: {x, y, distance, container, items = {text, ...}}
function lootoverlay.scan()
	local level = getLevel()
	local actor = level and level.playerActor

	if not actor or not actor.x or not actor.y then
		return nil
	end

	local templates = itemTemplates()
	local px, py = actor.x, actor.y

	local xMin = math.max(1, px - config.radius)
	local xMax = math.min(level.xMax or 0, px + config.radius)
	local yMin = math.max(1, py - config.radius)
	local yMax = math.min(level.yMax or 0, py + config.radius)

	local found = {}

	for x = xMin, xMax do
		if level.grid[x] then
			for y = yMin, yMax do
				local visible = level.FoV and level.FoV[x] and level.FoV[x][y]
				local stack = visible and level.grid[x][y]

				if stack then
					-- Top down, and stop at the first loot-bearing tile: that is the
					-- one whose icon levelWindow draws.
					for i = #stack, 1, -1 do
						local tile = stack[i]

						if tile and not tile.isHidden and tile.visibilityAlpha ~= 0
							and tile.loot and tile.loot[1]
						then
							local items = {}
							for _, entry in ipairs(tile.loot) do
								local text = itemText(entry, templates)
								if text then
									items[#items + 1] = text
								end
							end

							found[#found + 1] = {
								x = x,
								y = y,
								distance = describe.distance(x - px, y - py),
								container = tile.description or tile.name,
								unlootable = tile.unlootable and true or false,
								items = items,
							}
							break
						end
					end
				end
			end
		end
	end

	table.sort(found, function(a, b)
		if a.distance ~= b.distance then
			return a.distance < b.distance
		end
		if a.x ~= b.x then
			return a.x < b.x
		end
		return a.y < b.y
	end)

	return found, px, py
end

--------------------------------------------------------------------------------
-- Phrasing
--
-- Pure and exposed, so the testbed can assert the wording without capturing
-- speech.
--------------------------------------------------------------------------------

-- One block per container, so the console history can walk them back with [ and ]
-- after the utterance has gone by — a chest with six reagents in it is more than
-- anyone holds in their head on one hearing.
function lootoverlay.blocks(found, px, py)
	if not found then
		return nil
	end

	if #found == 0 then
		return {"No loot in view"}
	end

	local blocks = {}
	local shown = math.min(#found, config.maxTiles)

	for i = 1, shown do
		local entry = found[i]
		local parts = {}

		if entry.container then
			-- Descriptions are sentences ("A wooden chest."); the trailing stop would
			-- land mid-clause once we append the position.
			parts[#parts + 1] = (entry.container:gsub("%.%s*$", ""))
		else
			parts[#parts + 1] = "something"
		end

		parts[#parts + 1] = describe.offset(entry.x - px, entry.y - py)

		if entry.unlootable then
			parts[#parts + 1] = "cannot be taken"
		end

		if #entry.items > 0 then
			parts[#parts + 1] = table.concat(entry.items, ", ")
		else
			parts[#parts + 1] = "contents unknown"
		end

		blocks[#blocks + 1] = table.concat(parts, ", ")
	end

	if #found > shown then
		blocks[#blocks + 1] = string.format("and %d more", #found - shown)
	end

	return blocks
end

function lootoverlay.speak()
	local found, px, py = lootoverlay.scan()

	if not found then
		return
	end

	local blocks = lootoverlay.blocks(found, px, py)

	-- Interrupting: this is a direct answer to a key the player just pressed.
	speech.say(table.concat(blocks, ". "), true)

	if #found > 0 then
		for _, block in ipairs(blocks) do
			pcall(history.append, block, "loot")
		end
	end
end

--------------------------------------------------------------------------------
-- Watching the game's flag
--------------------------------------------------------------------------------

local levelWindow

-- The instance is a file-local of states/ingame, created once in open() and
-- handed to the other ingame states through params. Cached, because
-- getAnyUpvalue walks every function in the state table.
local function getLevelWindow()
	if levelWindow then
		return levelWindow
	end

	local stateTable = menus.getStateTable("ingame")
	levelWindow = menus.getAnyUpvalue(stateTable, "levelWindow")

	return levelWindow
end

-- Only the ingame family draws the overlay, and only there is levelWindow even
-- assigned — so this also keeps getAnyUpvalue from being retried every frame
-- while the player is sitting in the main menu.
local function inGameplay()
	local ok, states = pcall(require, "states")
	if not ok then
		return false
	end
	local current = states.getCurrent()
	return type(current) == "string" and current:sub(1, 6) == "ingame"
end

-- Version-bump canary for the startup self-test. If `levelWindow` is ever
-- renamed in states/ingame.lua this reports it at startup, instead of the loot
-- key going quietly silent halfway through a playthrough.
function lootoverlay.probeStatus()
	local stateTable = menus.getStateTable("ingame")

	if not stateTable then
		return "BROKEN: cannot load states/ingame"
	end

	if not menus.hasUpvalue(stateTable, "levelWindow") then
		return "PROBE BROKEN: no upvalue 'levelWindow' in states/ingame"
	end

	return menus.getAnyUpvalue(stateTable, "levelWindow")
		and "ok" or "ok (unset until gameplay starts)"
end

function lootoverlay.update()
	if not inGameplay() then
		return
	end

	local window = getLevelWindow()

	if not window then
		return
	end

	local enabled = window.itemsHighlightEnabled and true or false

	if enabled and not wasEnabled then
		lootoverlay.speak()
	end

	wasEnabled = enabled
end

return lootoverlay