-- DESCRIPTION: Guess the five-letter word in six tries

local WORDS_PATH = "/.apps/Wordle/words.txt"
local WORD_LENGTH = 5
local MAX_GUESSES = 6

local keyboard = {
    { "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P" },
    { "A", "S", "D", "F", "G", "H", "J", "K", "L" },
    { "OK", "Z", "X", "C", "V", "B", "N", "M", "DEL" }
}

local answer = nil
local current = ""
local guesses = {}
local results = {}
local keyStates = {}
local cursorRow = 1
local cursorColumn = 1
local message = ""
local gameOver = false
local firstDraw = true
local needsDraw = true

-- Word Source - Replace only this function to fetch answers from another source.
local function getRandomWord()
    local size = fs.fileSize(WORDS_PATH)
    if not size then return nil, "Missing " .. WORDS_PATH end
    if size == 0 then return nil, "Word list is empty" end

    for _ = 1, 8 do
        local word = fs.readLineAt(WORDS_PATH, math.random(0, size - 1)) or fs.readLineAt(WORDS_PATH, 0)
        if word then
            word = word:match("^%s*(.-)%s*$")
            if #word == WORD_LENGTH and word:match("^%a+$") then return word:upper() end
        end
    end

    return nil, "Word list has no five-letter words"
end

local function startGame()
    local errorMessage
    answer, errorMessage = getRandomWord()
    current = ""
    guesses = {}
    results = {}
    keyStates = {}
    cursorRow = 1
    cursorColumn = 1
    gameOver = not answer
    message = errorMessage or "Pick a letter"
    firstDraw = true
    needsDraw = true
end

local function evaluateGuess(guess)
    local status = {}
    local remaining = {}

    for index = 1, WORD_LENGTH do
        local letter = answer:sub(index, index)
        if guess:sub(index, index) == letter then
            status[index] = 2
        else
            remaining[letter] = (remaining[letter] or 0) + 1
        end
    end

    for index = 1, WORD_LENGTH do
        if not status[index] then
            local letter = guess:sub(index, index)
            if (remaining[letter] or 0) > 0 then
                status[index] = 1
                remaining[letter] = remaining[letter] - 1
            else
                status[index] = 0
            end
        end
    end

    return status
end

local function submitGuess()
    if #current ~= WORD_LENGTH then
        message = "Enter five letters"
        return
    end

    local status = evaluateGuess(current)
    guesses[#guesses + 1] = current
    results[#results + 1] = status

    for index = 1, WORD_LENGTH do
        local letter = current:sub(index, index)
        keyStates[letter] = math.max(keyStates[letter] or 0, status[index])
    end

    if current == answer then
        message = "Solved! Press OK for a new word"
        gameOver = true
    elseif #guesses == MAX_GUESSES then
        message = answer .. " - Press OK for a new word"
        gameOver = true
    else
        message = tostring(MAX_GUESSES - #guesses) .. " guesses left"
    end
    current = ""
end

local function useKey(key)
    if key == "OK" then
        submitGuess()
    elseif key == "DEL" then
        current = current:sub(1, -2)
        message = "Pick a letter"
    elseif #current < WORD_LENGTH then
        current = current .. key
        message = "Pick a letter"
    end
    needsDraw = true
end

local function centeredText(font, x, y, width, text, color, style)
    local textWidth = gui.getTextWidth(font, text, style)
    gui.drawText(font, x + math.floor((width - textWidth) / 2), y, text, color, style)
end

local function drawTile(letter, status, x, y, size)
    local fill = COLOR_WHITE
    local textColor = COLOR_BLACK

    if status == 2 then
        fill = COLOR_BLACK
        textColor = COLOR_WHITE
    elseif status == 1 then
        fill = COLOR_LIGHT_GRAY
    elseif status == 0 then
        fill = COLOR_DARK_GRAY
        textColor = COLOR_WHITE
    end

    if status ~= nil then gui.fillRoundedRect(x, y, size, size, 5, fill) end
    gui.drawRoundedRect(x, y, size, size, 2, 5, COLOR_BLACK)
    -- Present Marker - Gray shades alone are hard to tell apart on e-ink, so "in word, wrong spot" also gets an inset ring.
    if status == 1 then gui.drawRoundedRect(x + 5, y + 5, size - 10, size - 10, 2, 3, COLOR_BLACK) end
    if letter ~= "" then
        centeredText(FONT_NOTOSANS_16, x, y + math.floor(size / 2) - 10, size, letter, textColor, STYLE_BOLD)
    end
end

local function drawGrid(width, height)
    local gap = 5
    local size = math.min(62, math.floor((width - 60 - gap * (WORD_LENGTH - 1)) / WORD_LENGTH),
        math.floor((height * 0.53 - gap * (MAX_GUESSES - 1)) / MAX_GUESSES))
    local gridWidth = size * WORD_LENGTH + gap * (WORD_LENGTH - 1)
    local startX = math.floor((width - gridWidth) / 2)
    local startY = 72

    for row = 1, MAX_GUESSES do
        local word = guesses[row] or (row == #guesses + 1 and current or "")
        local status = results[row]
        for column = 1, WORD_LENGTH do
            drawTile(word:sub(column, column), status and status[column] or nil,
                startX + (column - 1) * (size + gap), startY + (row - 1) * (size + gap), size)
        end
    end

    return startY + MAX_GUESSES * size + (MAX_GUESSES - 1) * gap
end

local function drawKeyboard(width, height, top)
    local gap = 4
    local margin = 12
    local keyWidth = math.floor((width - margin * 2 - gap * 9) / 10)
    local keyHeight = math.min(48, math.floor((height - top - 70 - gap * 2) / 3))

    for rowIndex, row in ipairs(keyboard) do
        local rowWidth = #row * keyWidth + (#row - 1) * gap
        local startX = math.floor((width - rowWidth) / 2)
        local y = top + (rowIndex - 1) * (keyHeight + gap)

        for columnIndex, key in ipairs(row) do
            local x = startX + (columnIndex - 1) * (keyWidth + gap)
            local status = keyStates[key]
            local fill = status == 2 and COLOR_BLACK or status == 1 and COLOR_LIGHT_GRAY or
                status == 0 and COLOR_DARK_GRAY or COLOR_WHITE
            local textColor = (status == 2 or status == 0) and COLOR_WHITE or COLOR_BLACK

            gui.fillRoundedRect(x, y, keyWidth, keyHeight, 4, fill)
            gui.drawRoundedRect(x, y, keyWidth, keyHeight, 1, 4, COLOR_BLACK)
            if status == 1 then gui.drawRoundedRect(x + 4, y + 4, keyWidth - 8, keyHeight - 8, 1, 3, COLOR_BLACK) end
            if rowIndex == cursorRow and columnIndex == cursorColumn then
                gui.drawRoundedRect(x + 2, y + 2, keyWidth - 4, keyHeight - 4, 3, 3, textColor)
            end
            centeredText(FONT_SMALL, x, y + math.floor(keyHeight / 2) - 7, keyWidth, key, textColor, STYLE_BOLD)
        end
    end
end

local function render()
    local width, height = gui.width(), gui.height()
    gui.clear()
    gui.drawCenteredText(FONT_NOTOSANS_16, 16, "WORDLE", COLOR_BLACK, STYLE_BOLD)
    gui.drawCenteredText(FONT_SMALL, 48, message, COLOR_BLACK, STYLE_REGULAR)

    if answer then
        local gridBottom = drawGrid(width, height)
        drawKeyboard(width, height, gridBottom + 14)
    end

    gui.drawButtonHints("<<", "Select", "<", ">")
    gui.refresh(firstDraw and REFRESH_HALF or REFRESH_FAST)
    firstDraw = false
    needsDraw = false
end

function init()
    startGame()
end

function draw()
    if input.wasPressed("back") then
        sys.exit()
        return
    end

    if gameOver and answer then
        if input.wasPressed("confirm") then startGame() end
    elseif answer then
        if input.wasPressed("left") then
            cursorColumn = cursorColumn == 1 and #keyboard[cursorRow] or cursorColumn - 1
            needsDraw = true
        elseif input.wasPressed("right") then
            cursorColumn = cursorColumn == #keyboard[cursorRow] and 1 or cursorColumn + 1
            needsDraw = true
        elseif input.wasPressed("up") then
            cursorRow = cursorRow == 1 and #keyboard or cursorRow - 1
            cursorColumn = math.min(cursorColumn, #keyboard[cursorRow])
            needsDraw = true
        elseif input.wasPressed("down") then
            cursorRow = cursorRow == #keyboard and 1 or cursorRow + 1
            cursorColumn = math.min(cursorColumn, #keyboard[cursorRow])
            needsDraw = true
        elseif input.wasPressed("confirm") then
            useKey(keyboard[cursorRow][cursorColumn])
        end
    end

    if needsDraw then render() end
end