CCGUI text

--[[

    ComputerCraft GUI
    Text element

--]]

ccgui = ccgui or {}

local TextElement = common.newClass({
    -- Text
    text = "",
    -- Text alignment
    align = ccgui.Align.Left,
    valign = ccgui.VAlign.Top,
    -- Private: lines to draw
    lines = nil,
    lineCount = 0
}, ccgui.Element)
ccgui.TextElement = TextElement

function TextElement:init()
    ccgui.Element.init(self)

    self:setText(self.text)

    self:on("paint", self.drawText, self)
end

function TextElement:setText(text)
    self.text = text or ""
    self.lines = {}
    --self:markRepaint()
end

local function wrapLine(str, limit)
    -- Wrap in words
    str = string.gsub(str, "(%S+)",
        function(word)
            local length, lastBreak = #word, 0
            while length - lastBreak > limit do
                lastBreak = lastBreak + limit
                word = string.sub(word, 1, lastBreak) .. "\n" .. string.sub(word, lastBreak+1)
            end
            return word
        end
    )
    -- Wrap on word boundaries
    local lastBreak = 1
    return string.gsub(str, "(%s+)()(%S+)()",
        function(spaces, start, word, finish)
            if finish - lastBreak > limit then
                lastBreak = start
                return "\n"..word
            end
        end
    )
end

local function splitLines(str)
    local t = {}
    local function helper(line)
        table.insert(t, line)
        return ""
    end
    helper((string.gsub(str, "(.-)\n", helper)))
    return t
end

function TextElement.wordwrap(str, limit)
    -- Clean leading spaces after newlines
    --str = string.gsub(str, "%s*\n%s+", "\n")
    -- Clean subsequent spaces
    --str = string.gsub(str, "%s%s+", " ")
    -- Wrap every single line
    str = string.gsub(str, "[^\n]+",
        function(line)
            return wrapLine(line, limit)
        end
    )
    return str
end

function TextElement:calcSize(size)
    -- Get inner bounding box
    local bbox = self:inner(size)

    -- Wrap text to fit bounding box width
    local text = self.wordwrap(self.text, bbox.w)

    -- Split in lines
    self.lines = splitLines(text)

    -- Get longest line length
    local nw = 0
    for i,line in ipairs(self.lines) do
        local len = #line
        if(len > nw) then nw = len end
    end

    -- Draw less lines if height limited
    local nh = math.min(bbox.h, #self.lines)
    self.lineCount = nh

    -- Get inner bounding box with new size
    bbox = ccgui.newRectangle(bbox.x, bbox.y, nw, nh)
    -- Use outer size box
    self.size = self:outer(bbox)
end

function TextElement:drawText()
    -- Get inner bounding box
    local bbox = self:inner(self.bbox)

    -- Vertical align
    local firstLine, y = 1, bbox.y
    local nLines, nLinesToPaint = #self.lines, self.lineCount
    if self.valign == ccgui.VAlign.Center then
        y = y + math.floor((bbox.h - nLinesToPaint)/2)
        if nLines > nLinesToPaint then
            firstLine = math.floor((nLines - nLinesToPaint)/2) + 1
        end
    elseif self.valign == ccgui.VAlign.Bottom then
        y = y + bbox.h - nLinesToPaint
        if nLines > nLinesToPaint then
            firstLine = nLines - nLinesToPaint + 1
        end
    end

    local lastLine = firstLine + nLinesToPaint - 1
    for i=firstLine,lastLine do
        local line = self.lines[i]
        -- Horizontal align
        local x = bbox.x
        local len = #(line)
        if self.align == ccgui.Align.Center then
            x = x + math.floor((bbox.w - len)/2)
        elseif self.align == ccgui.Align.Right then
            x = x + bbox.w - len
        end
        -- Write text
        self:draw(x, y, line, self.foreground, self.background, bbox)
        y = y + 1
    end
end