CCGUI flow

--[[

    ComputerCraft GUI
    Flow container

--]]

ccgui = ccgui or {}

local FlowContainer = common.newClass({
    -- Orientation
    horizontal = false,
    -- Spacing between children
    spacing = 0
}, ccgui.Container)
ccgui.FlowContainer = FlowContainer

function FlowContainer:init()
    ccgui.Container.init(self)

    -- Orientation
    self.horizontal = not not self.horizontal
end

function FlowContainer:calcSize(size)
    -- Get inner box
    local cbox = self:inner(size)

    -- Flow dimension
    local flowDim = (self.horizontal and "w") or "h"
    -- Fixed dimension
    local fixedDim = (self.horizontal and "h") or "w"

    -- Flow size
    local flowSize = 0
    -- Remaining flow size
    local remaining = cbox[flowDim]
    -- Fixed size
    local fixedSize = cbox[fixedDim]
    -- Maximum fixed size
    local maxFixed = 0

    -- Children to be stretched
    local stretchChildren = {}

    -- Update sizes of children
    self:eachVisible(function(child, i, isLast)
        -- No spacing on last child
        local spacing = (not isLast and self.spacing) or 0
        -- Handle stretched children later
        if child.stretch then
            -- Remove spacing from remaining
            -- and add to flow size
            flowSize = flowSize + spacing
            remaining = remaining - spacing
            -- Add to stretched children
            table.insert(stretchChildren, child)
            return
        end
        -- Get child size
        child:calcSize(ccgui.Rectangle:new{
            [flowDim] = remaining,
            [fixedDim] = fixedSize
        })
        -- Remove child size and spacing from remaining
        -- and add to flow size
        local childSize = child.size[flowDim] + spacing
        flowSize = flowSize + childSize
        remaining = remaining - childSize
        -- Update maximum fixed size
        maxFixed = math.max(maxFixed, child.size[fixedDim])
    end)

    -- Divide remaining size over stretched children
    local stretchSize = math.floor(remaining / #stretchChildren)
    local firstStretch = stretchSize + (remaining % #stretchChildren)
    for i,child in ipairs(stretchChildren) do
        local childSize = (i == 1 and firstStretch) or stretchSize
        -- Get child size
        child:calcSize(ccgui.Rectangle:new{
            [flowDim] = childSize,
            [fixedDim] = fixedSize
        })
        -- Force flow size
        child.size[flowDim] = childSize
        -- Add child size to flow size
        flowSize = flowSize + childSize
        -- Update maximum fixed size
        maxFixed = math.max(maxFixed, child.size[fixedDim])
    end

    -- Enforce fixed size
    self:eachVisible(function(child, i)
        child.size[fixedDim] = maxFixed
    end)

    -- Get children size box
    local bbox = ccgui.Rectangle:new{
        [flowDim] = flowSize,
        [fixedDim] = maxFixed
    }
    -- Use outer size box
    self.size = self:outer(bbox)
end

function FlowContainer:calcLayout(bbox)
    -- Get inner box for children bounding box
    local cbox = self:inner(bbox)

    -- Collect old child bounding boxes
    local childBboxes = {}
    self:eachVisible(function(child, i)
        childBboxes[i] = child.bbox
    end)

    -- Flow coordinate
    local flowCoord = (self.horizontal and "x") or "y"
    -- Fixed coordinate
    local fixedCoord = (self.horizontal and "y") or "x"
    -- Flow dimension
    local flowDim = (self.horizontal and "w") or "h"
    -- Fixed dimension
    local fixedDim = (self.horizontal and "h") or "w"

    -- Flow position
    local flowPos = cbox[flowCoord]
    -- Fixed size
    local fixedPos, fixedSize = cbox[fixedCoord], cbox[fixedDim]

    -- Update layout of children
    self:eachVisible(function(child, i, isLast)
        local spacing = (not isLast and self.spacing) or 0
        -- Get child bounding box
        child:calcLayout(ccgui.Rectangle:new{
            [flowCoord] = flowPos,
            [fixedCoord] = fixedPos,
            [flowDim] = child.size[flowDim],
            [fixedDim] = fixedSize
        })
        -- Force size
        child.bbox[flowDim] = child.size[flowDim]
        child.bbox[fixedDim] = fixedSize
        -- Add child size and spacing to flow position
        local childSize = child.bbox[flowDim] + spacing
        flowPos = flowPos + childSize
    end)

    -- Check for child bounding box changes
    --[[local childBboxChanged = false
    self:eachVisible(function(child, i)
        local oldBbox = childBboxes[i]
        if oldBbox == nil or oldBbox ~= child.bbox then
            -- Bounding box changed, repaint child and container
            child:markRepaint()
            childBboxChanged = true
        end
    end)
    if childBboxChanged then
        self:markRepaint()
    end]]--

    -- Use given bounding box
    self.bbox = bbox
end