local TextBox = {}
TextBox.__index = TextBox

function TextBox.new(x, y, w, h, delay, linePadding)
    local this = {
        x = x,
        y = y,
        width = w,
        height = h,
        padding = {
            x = 8,
            y = 16
        },
        lineSpacing = linePadding,
        typingTimer = 0,
        delayTimer = 0,
        typeDelay = delay,
        isTyping = false,
        isDelaying = false,
        text = "",
        currentIndex = 0,

        colourChanges = {},
        delays = {},
        speedChanges = {},
        clearTexts = {},
    }
    setmetatable(this, TextBox)
    return this
end

function TextBox:getRect()
    return self.x, self.y, self.width, self.height
end

function TextBox:begin()
    self.isTyping = true
end

local function rollBackChanges(tbl, currentIndex)
    local newTable = {}
    for index, value in pairs(tbl) do
        if index - currentIndex >= 0 then
            newTable[index - currentIndex] = value
        end
    end
    return newTable
end

function TextBox:reset()
    self.colourChanges = rollBackChanges(self.colourChanges, self.currentIndex)
    self.delays        = rollBackChanges(self.delays,        self.currentIndex)
    self.speedChanges  = rollBackChanges(self.speedChanges,  self.currentIndex)
    self.clearTexts    = rollBackChanges(self.clearTexts,    self.currentIndex)

    text = text:sub(currentIndex)
    currentIndex = 0
end

function TextBox:addText(newText)
    self.text = self.text .. newText
end

function TextBox:addLine(newText)
    self:addText(newText)
    self:addText("\n")
end

function TextBox:clear()
    self.clearTexts[self.text:len()] = true
end

function TextBox:setColour(r, g, b, a)
    local a = a or 255
    self.colourChanges[self.text:len()] = {r, g, b, a}
end

function TextBox:delay(delayDuration)
    self.delays[self.text:len()] = delayDuration
end

function TextBox:setSpeed(newDelay)
    self.speedChanges[self.text:len()] = newDelay
end

function TextBox:update(dt)
    if self.isDelaying and self.delayTimer <= 0 then
        self.isDelaying = false
    elseif self.isDelaying then
        self.delayTimer = math.max(0, self.delayTimer - dt)
        return
    end
    if self.currentIndex == self.text:len() then
        self.isTyping = false
    end

    if not self.isTyping then return end

    self.typingTimer = self.typingTimer + dt

    while self.typingTimer >= self.typeDelay do
        self.typingTimer = self.typingTimer - self.typeDelay
        self.currentIndex = self.currentIndex + 1

        local shouldReturn = false

        if self.speedChanges[self.currentIndex] then
            self.typeDelay = self.speedChanges[self.currentIndex]
        end

        if self.delays[self.currentIndex] then
            self.delayTimer = self.delays[self.currentIndex]
            self.isDelaying = true
            shouldReturn = true
        end

        if self.clearTexts[self.currentIndex] then
            self:reset()
            shouldReturn = true
        end

        if shouldReturn then return end

        if self.currentIndex >= self.text:len() then
            self.currentIndex = self.text:len()
            self.isTyping = false
        end
    end

end

function TextBox:draw()
    local charX = self.padding.x
    local charY = self.padding.y
    for i = 0, self.currentIndex do
        if self.colourChanges[i] then
            love.graphics.setColor(self.colourChanges[i])
        end
        local letter = self.text:sub(i, i)
        if letter == "\n" then
            charY = charY + self.lineSpacing
            charX = self.padding.x
        else
            local word = ""
            for n = i, self.text:len() do
                if self.text:sub(n, n) == " " then break end
                word = word .. self.text:sub(n, n)
            end
            if charX + love.graphics.getFont():getWidth(word) >= self.width + self.padding.x then
                charY = charY + self.lineSpacing
                charX = self.padding.x
            end
            love.graphics.print(self.text:sub(i,i), self.x + charX, self.y + charY)
            charX = charX + love.graphics.getFont():getWidth(self.text:sub(i,i))
        end
    end
end

return TextBox