-- states/journal.lua — quests, lore, bestiary, components, recipes, tutorials.
--
-- Visually the screen is three things at once:
--
--   * a row of TABS across the top (Quests / Lore / Bestiary / Components /
--     Recipes / Tutorials), changed with tabLeft / tabRight;
--   * a scrolling LIST of entries down the left, each an icon plus a title,
--     changed with up / down;
--   * the selected entry's TEXT filling the right-hand page, paginated, with a
--     "< 2 / 3 >" counter under it and left / right flipping pages.
--
-- Only the first two were ever announced, so selecting an entry read its title
-- and then nothing — the page holding the actual content was silent, and page
-- flipping was silent too. That is the whole point of the screen.
--
-- The page is `options[selectedOption].pages[selectedPageId]`, a list of text
-- blocks (`{text = ..., color = ..., icon = ...}`). Its length is bounded by
-- what fits on screen, so a page is safe to speak in one go; it is also pushed
-- into the console history so [ and ] can walk it back, the same trick
-- _textscreen.lua uses for the manual.
--
-- Uses getAnyUpvalue because activeTabIndex, options, selectedOption and
-- selectedPageId are touched by different functions here (gotoTab,
-- prepareOptions, selectPage, keypressed).

local history = require("accessibility.history")

local lastTab
local lastEntry
local lastPushedPage
local lastKey
local lastText

-- The page splitter concatenates the game's own wrapped lines with "\n", so a
-- block's text carries hard newlines that are pure layout. Flatten them, or the
-- screen reader pauses mid-sentence at every wrap point.
local function flatten(text)
	return (tostring(text):gsub("%s*\n%s*", " "):gsub("^%s+", ""):gsub("%s+$", ""))
end

local function pageBlocks(page)
	local blocks = {}

	for _, textBlock in ipairs(page) do
		if type(textBlock) == "table" and type(textBlock.text) == "string" then
			local text = flatten(textBlock.text)
			if text ~= "" then
				blocks[#blocks + 1] = text
			end
		end
	end

	return blocks
end

return {
	-- Called by menus.announceScreen each time the journal is opened, so the tab
	-- and title lead again rather than being suppressed as "unchanged" from the
	-- last visit.
	reset = function()
		lastTab = nil
		lastEntry = nil
		lastPushedPage = nil
		lastKey = nil
		lastText = nil
	end,

	read = function(stateTable, menus)
		local tabIndex = menus.getAnyUpvalue(stateTable, "activeTabIndex")
		local tabsList = menus.getAnyUpvalue(stateTable, "tabsList")
		local options = menus.getAnyUpvalue(stateTable, "options")
		local selected = menus.getAnyUpvalue(stateTable, "selectedOption")
		local pageId = menus.getAnyUpvalue(stateTable, "selectedPageId")

		if type(tabIndex) ~= "number" or type(tabsList) ~= "table" then
			return nil, nil
		end

		local optionCount = type(options) == "table" and #options or -1
		local entry = type(options) == "table" and type(selected) == "number"
			and options[selected] or nil

		local key = table.concat({
			tostring(tabIndex), tostring(selected), tostring(pageId), tostring(optionCount)
		}, ":")

		-- read() is called from several places for the same focus: the per-frame
		-- poll, the post-keypress announce, the "repeat what's focused" key, and
		-- the testbed's before/after probes. Only the FIRST read of a given focus
		-- may advance the suppression state below -- otherwise a poll would
		-- consume the "tab changed" flag and the announcement that follows would
		-- come out without its heading. So later reads of the same key replay the
		-- text verbatim, which also makes the repeat key say the full thing.
		if key == lastKey then
			return lastText, key
		end

		local tab = tabsList[tabIndex]
		local tabName = tab and tab.header or ("tab " .. tabIndex)

		local parts = {}

		-- Lead with the tab only when it just changed, so stepping through a long
		-- quest list doesn't repeat "Quests" on every line.
		if tabIndex ~= lastTab then
			parts[#parts + 1] = tabName
		end

		if optionCount == 0 then
			parts[#parts + 1] = "empty"
		elseif entry then
			-- Repeating the title on every page flip would bury the page you just
			-- turned to, so the title leads only when the entry itself changed.
			local entryKey = tostring(tabIndex) .. ":" .. tostring(selected)

			if entryKey ~= lastEntry then
				parts[#parts + 1] = entry.title or entry.header or entry.name or "?"
				parts[#parts + 1] = selected .. " of " .. optionCount
			end

			local pages = entry.pages
			local page = type(pages) == "table" and type(pageId) == "number" and pages[pageId]

			if page then
				-- Only worth saying which page you are on when there is more than one.
				if #pages > 1 then
					parts[#parts + 1] = "page " .. pageId .. " of " .. #pages
				end

				local blocks = pageBlocks(page)

				for _, block in ipairs(blocks) do
					parts[#parts + 1] = block
				end

				if #blocks == 0 then
					parts[#parts + 1] = "no text"
				end

				-- Mirror the page into the review buffer so [ and ] can walk it
				-- block by block after the utterance has gone by.
				local pageKey = entryKey .. ":" .. tostring(pageId)
				if pageKey ~= lastPushedPage then
					lastPushedPage = pageKey
					for _, block in ipairs(blocks) do
						pcall(history.append, block, "journal")
					end
				end
			end

			lastEntry = entryKey
		end

		lastTab = tabIndex
		lastKey = key
		lastText = #parts > 0 and table.concat(parts, ", ") or nil

		return lastText, key
	end,
}