term = require("term")
local component = require("component")
local event = require("event")
local unicode = require("unicode")
gpu = term.gpu()

function newForm(gpu, textBoxes)
    local self = {}
    self.gpu = gpu
    self.textBoxes = textBoxes
    local firstBox = nil
    local previousBox = nil
    for index,box in ipairs(self.textBoxes) do
        if firstBox == nil then
            firstBox = box
        end
        if previousBox ~= nil then
            previousBox.nextBox = box
        end
        box.gpu = gpu
        box:fullRender()
        box.form = self
        previousBox = box
    end
    if previousBox ~= nil and previousBox ~= firstBox then
        previousBox.nextBox = firstBox
    end

    function self:changeColors(background, border, value, hint)
        for index,box in ipairs(self.textBoxes) do
            box:changeColors(background, border, value, hint)
        end
    end

    function self:changeBackgoundColor(color)
        for index,box in ipairs(self.textBoxes) do
            box:changeBackgroundColor(color)
        end
    end
    function self:changeBorderColor(color)
        for index,box in ipairs(self.textBoxes) do
            box:changeBorderColor(color)
        end
    end
    function self:changeValueColor(color)
        for index,box in ipairs(self.textBoxes) do
            box:changeValueColor(color)
        end
    end
    function self:changeHintTextColor(color)
        for index,box in ipairs(self.textBoxes) do
            box:changeHintTextColor(color)
        end
    end

    function self:checkForFocus(x, y)
        for index,box in ipairs(self.textBoxes) do
            if box:isClickInRange(x,y) then
                box:onFocus(x)
            end
        end
    end
    return self
end

function newTextbox(x,y,width,onValueChanged,initialValue,hintText)
    local self = {}
    self.hintText = hintText or ""
    self.value = initialValue or ""
    self.previousValue = self.value
    self.gpu = nil
    self.scrollPosition = 1
    self.x = x
    self.y = y
    self.cursor = 1
    self.width = width
    self.form = nil

    --default cruddy colors
    self.backgroundColor = 0x0000FF
    self.borderColor = 0x0000FF
    self.valueColor = 0x0000FF
    self.hintTextColor = 0x0000FF

    function self:changeColors(background, border, value, hint)
        self.backgroundColor, self.borderColor, self.valueColor, self.hintTextColor =
            background or self.backgroundColor, border or self.borderColor,
            value or self.valueColor, hint or self.hintTextColor
        self:fullRender()
    end

    function self:changeBackgoundColor(color) self.backgroundColor = color self:fullRender() end
    function self:changeBorderColor(color) self.borderColor = color self:fullRender() end
    function self:changeValueColor(color) self.valueColor = color self:fullRender() end
    function self:changeHintTextColor(color) self.hintTextColor = color self:fullRender() end

    self.active = false
    self.onValueChanged = onValueChanged or function(newValue) end
    self.nextBox = nil
    function self:setValue(val)
        self.value = val
        self.cursor = 1
        self.scrollPosition = 1
        self:render()
    end
    function self:clear()
        self:setValue("")
    end
    function self:fullRender()
        self.gpu.setBackground(self.backgroundColor)
        self.gpu.setForeground(self.borderColor)
        local topLine = unicode.char(0x2554)
        local bottomLine = unicode.char(0x255A)
        for i=1,self.width,1 do
            topLine = topLine..unicode.char(0x2550)
            bottomLine = bottomLine..unicode.char(0x2550)
        end
        topLine = topLine..unicode.char(0x2557)
        bottomLine = bottomLine..unicode.char(0x255D)
        self.gpu.set(self.x-1,self.y-1,topLine)
        self.gpu.set(self.x-1,self.y+1,bottomLine)
        self.gpu.set(self.x-1,self.y,unicode.char(0x2551))
        self.gpu.set(self.x+self.width,self.y,unicode.char(0x2551))
        self:render()
    end
    function self:render()
        if self.cursor - self.scrollPosition >= self.width then
            self.scrollPosition = self.cursor - self.width + 1
        end
        self.gpu.setBackground(self.backgroundColor)
        self.gpu.setForeground(self.valueColor)
        self.gpu.fill(self.x,self.y,self.width,1," ")
        if string.len(self.value) > 0 then
            self.gpu.set(self.x,self.y,string.sub(self.value,self.scrollPosition,self.scrollPosition+self.width-1))
        elseif string.len(self.hintText) > 0 then
            self.gpu.setForeground(self.hintTextColor)
            self.gpu.set(self.x,self.y,self.hintText)
            self.gpu.setForeground(self.valueColor)
        end
        self:moveCursor()
    end
    function self:moveCursor()
        if self.cursor > string.len(self.value) then
            self.cursor = string.len(self.value)+1
        end
        term.setCursor(self.x+self.cursor-self.scrollPosition,self.y)
    end
    function self:isClickInRange(mouseX,mouseY)
        return mouseY == self.y and mouseX >= self.x and mouseX <= self.x + self.width - 1
    end
    function self:onFocus(mouseX)
        mouseX = mouseX or self.x+string.len(self.value)
        self.cursor = mouseX-self.x+self.scrollPosition
        self:render()
        term.setCursorBlink(true)
        self.active = true
        self.previousValue = self.value
        local goToNext = false
        local lastX,lastY = nil,nil
        while self.active do
            local eventType, p1, p2, p3, p4, p5 = term.pull()
            if eventType == "touch" then
                local screenAddress, x, y, button, player = p1, p2, p3, p4, p5
                if self:isClickInRange(x,y) then
                    self.cursor = x-self.x+self.scrollPosition
                    self:moveCursor()
                else
                    self.active = false
                    lastX,lastY = x,y
                end
            elseif eventType == "key_down" then
                lastX, lastY = nil,nil
                local keyboardAddress, chr, code, player = p1, p2, p3, p4
                -- code 15 = tab
                -- printable char range = 32-126
                if chr >= 32 and chr <= 126 then
                    self.value = string.sub(self.value,1,self.cursor-1)..unicode.char(chr)..string.sub(self.value,self.cursor)
                    self.cursor = self.cursor+1
                    if self.cursor - self.scrollPosition > self.width then
                        self.scrollPosition = self.scrollPosition + 1
                    end
                    self:render()
                elseif code == 14 then --backspace
                    if string.len(self.value) > 0 and self.cursor > 1 then
                        self.value = string.sub(self.value,1,self.cursor-2)..string.sub(self.value,self.cursor)
                        self.cursor = self.cursor-1
                        if self.cursor - self.scrollPosition < 2  and self.scrollPosition > 1 then
                            self.scrollPosition = self.cursor - 1
                        end
                        self:render()
                    end
                elseif code == 203 then --left
                    if self.cursor > 1 then
                        self.cursor = self.cursor-1
                        if self.scrollPosition > 1 and self.cursor - self.scrollPosition < 1 then
                            self.scrollPosition = self.cursor
                        end
                        self:render()
                    end
                elseif code == 205 then --right
                    if self.cursor <= string.len(self.value) then
                        self.cursor = self.cursor+1
                        self:render()
                    end
                elseif code == 28 then --enter
                    self.active = false
                elseif code == 211 then --delete
                    if string.len(self.value) > 0 and self.cursor <= string.len(self.value) then
                        self.value = string.sub(self.value,1,self.cursor-1)..string.sub(self.value,self.cursor+1)
                        self:render()
                    end
                elseif code == 199 then --home
                    if self.cursor > 1 then
                        self.cursor = 1
                        self.scrollPosition = 1
                        self:render()
                    end
                elseif code == 207 then --end
                    if self.cursor <= string.len(self.value) then
                        self.cursor = string.len(self.value) + 1
                        self:render()
                    end
                elseif code == 15 then
                    if self.nextBox ~= nil then
                        goToNext = true
                        self.active = false
                    end
                end
            end
        end
        --blur control
        self.cursor = 1
        self.scrollPosition = 1
        self:render()
        if self.value ~= self.previousValue then
            self.onValueChanged(self.value)
        end
        if goToNext then
            self.nextBox:onFocus()
        end
        if self.form ~= nil and lastX ~= nil and lastY ~= nil then
            self.form:checkForFocus(lastX,lastY)
        end
    end
    return self
end


----------------------------------------------------------------


backgroundColor = 0x333333
textColor = 0x00FF00
hintTextColor = 0xCCCCCC

gpu.setBackground(backgroundColor)
term.clear()

local form = newForm(gpu,{
    newTextbox(5,5,15), newTextbox(22,5,15), newTextbox(39,5,15),
    newTextbox(5,8,15), newTextbox(22,8,15), newTextbox(39,8,15),
    newTextbox(5,11,15), newTextbox(22,11,15), newTextbox(39,11,15),
    newTextbox(20,20,15,function(newValue) term.setCursor(4,30) term.write("you entered "..newValue) end)
})

form:changeColors(backgroundColor, 0xFFFFFF, textColor, hintTextColor)

local cont = true
while cont do
    local eventType, p1, p2, p3, p4, p5 = event.pull()
    if eventType == "touch" then
        local x,y = p2,p3
        for index,box in ipairs(form.textBoxes) do
            if box:isClickInRange(x,y) then
                box:onFocus(x)
            end
        end
    elseif eventType == "key_down" then
        if p3 == 14 then --self is backspace probably
            for k,v in ipairs(form.textBoxes) do
                v:clear()
            end
            cont = false
            gpu.setBackground(0x000000)
            gpu.setForeground(0xFFFFFF)
            term.clear()
            term.setCursor(1,1)
        end
    end
end