-- states/worldmap.lua — travel destinations.
--
-- The screen is a painted map of Rimesia with area icons at real coordinates,
-- plus a description window carrying the area's blurb and the travel time. The
-- list on the side is only half of it: the icon says what KIND of place each area
-- is, the position says where it lies, and the description window says how long
-- getting there costs. All three were silent.
--
-- Why read() rather than probe/render: travel time needs the screen's
-- `currentAreaId`, and render(entry, index, total) is handed no state table.
-- `options`, `selectedOption` and `currentAreaId` are all file-locals in the same
-- chunk (states/worldmap.lua) and all are upvalues of exported functions, so
-- menus.getAnyUpvalue reaches them. `currentAreaId` is nil until the screen has
-- been opened once -- treat that as "omit the travel time", never as an error.
--
-- The blurb goes through details() on `=` rather than the focus line: it runs to
-- several sentences, and arrowing through nine areas would be unbearable.

local describe = require("accessibility.describe")
local worldmapModel = require("models.worldmap")

-- The 20 icon ids (models/interface/mapIcons.lua) are already readable words once
-- the underscores go: town, ruined_house, pirate_grave, witchwood... so this is a
-- transform rather than a lookup table, which also means a new id in a future
-- game version reads sensibly instead of vanishing.
--
-- Deliberately NOT an addition to mapIcons: icons.preprocess iterates that table
-- with pairs() and would try to treat any new table in it as an image.
local function areaType(iconId)
	if type(iconId) ~= "string" then
		return nil
	end
	return (iconId:gsub("_", " "))
end

-- The model area behind a list entry, or nil. worldmap.areas holds `false` in the
-- slots of erased areas (models/worldmap.lua:173), hence the type check.
local function modelArea(areaId)
	if type(areaId) ~= "number" then
		return nil
	end
	local area = worldmapModel.areas and worldmapModel.areas[areaId]
	if type(area) ~= "table" then
		return nil
	end
	return area
end

-- Compass bearing from one area to another in 0..1 map space.
--
-- describe.direction only tests the sign of each delta, so on floating-point
-- coordinates it would call almost everything diagonal. The deadzone below
-- suppresses a component that is small next to the other one, so a place almost
-- due north reads as "north" rather than "north-east". The 4/3 on x matches the
-- aspect correction the game's own distance maths uses
-- (models/worldmap.lua:64) so the bearing agrees with the travel time.
local DEADZONE = 0.25

local function bearing(fromArea, toArea)
	local dx = (toArea.x - fromArea.x) * 4 / 3
	local dy = toArea.y - fromArea.y

	local ax, ay = math.abs(dx), math.abs(dy)

	if ax < ay * DEADZONE then
		dx = 0
	elseif ay < ax * DEADZONE then
		dy = 0
	end

	if dx == 0 and dy == 0 then
		return nil
	end

	return describe.direction(dx, dy)
end

-- The focused list entry, plus the id of the area the player is standing in.
local function focus(stateTable, menus)
	local options = menus.getAnyUpvalue(stateTable, "options")
	local selected = menus.getAnyUpvalue(stateTable, "selectedOption")

	if type(options) ~= "table" or type(selected) ~= "number" then
		return nil
	end

	local entry = options[selected]
	if type(entry) ~= "table" then
		return nil
	end

	return entry, selected, #options, menus.getAnyUpvalue(stateTable, "currentAreaId")
end

return {
	-- Checked by menus.selfTest at startup: a game version that renames any of
	-- these says so on the console instead of going quiet on the travel screen.
	probeNames = {"options", "selectedOption", "currentAreaId"},

	read = function(stateTable, menus)
		local entry, index, total, currentAreaId = focus(stateTable, menus)
		if not entry then
			return nil, nil
		end

		local parts = {entry.name or "Unknown area"}

		-- entry.icon is already an image object (states/worldmap.lua:240); the id
		-- string lives on the model area.
		local area = modelArea(entry.id)
		local kind = area and areaType(area.icon)
		if kind then
			parts[#parts + 1] = kind
		end

		parts[#parts + 1] = index .. " of " .. total

		local here = modelArea(currentAreaId)
		if here and area and entry.id ~= currentAreaId then
			local which = bearing(here, area)
			if which then
				parts[#parts + 1] = which
			end
		end

		-- The game's own string, already finished English, including "You are
		-- currently here." Same call the screen makes at states/worldmap.lua:360.
		local travel
		if currentAreaId and entry.id then
			local ok, message = pcall(worldmapModel.getDistanceMessage, currentAreaId, entry.id)
			if ok and message and message ~= "" then
				travel = message
				parts[#parts + 1] = travel
			end
		end

		-- "Visited 3 days ago": on a map of similar-sounding place names this is
		-- the main way to tell where you have been.
		--
		-- Skipped when it duplicates the travel line. For the area you are
		-- standing in, getDistanceMessage and getLastVisitedMessage return the
		-- SAME sentence -- "You are currently here." (models/worldmap.lua:75-77
		-- and :106-107) -- which the screen gets away with because they are drawn
		-- in different panels, and which by ear is just said twice.
		if entry.visitedMessage and entry.visitedMessage ~= ""
			and entry.visitedMessage ~= travel
		then
			parts[#parts + 1] = entry.visitedMessage
		end

		if entry.isCompleted then
			parts[#parts + 1] = "completed"
		end
		if entry.isFavourite then
			parts[#parts + 1] = "favourite"
		end

		return table.concat(parts, ", "), index .. "/" .. total .. ":" .. tostring(entry.id)
	end,

	details = function(stateTable, menus, verbose)
		local entry = focus(stateTable, menus)
		if not entry then
			return nil
		end

		local blocks = {}

		if verbose then
			blocks[#blocks + 1] = entry.name or "Unknown area"
		end

		if entry.description and entry.description ~= "" then
			blocks[#blocks + 1] = entry.description
		end

		if #blocks == 0 then
			return nil
		end

		return blocks
	end,
}