-------------------------------------------------
-- @author Gregor Best <farhaven@googlemail.com>, Lukas Hrazky <lukkash@email.cz>
-- @copyright 2009 Gregor Best, Lukas Hrazky
-- @release @AWESOME_VERSION@
-------------------------------------------------

local setmetatable = setmetatable
local require = require
local ipairs = ipairs
local type = type
local insert = table.insert
local min = math.min
local max = math.max
local floor = math.floor
local util = require("awful.util")
local clone = util.table.clone

local margins = awful.widget.layout.margins
local layout = awful.widget.layout

local linear_common = {}

-- Calculates geometries for fixed layouts.
-- This generic function is used for all layouts exept flex.
-- It is written for horizontal layouts, but by using a special index 'idx' to access
-- all the geometry attributes, it is used for vertical layouts too. In that case, 'idx'
-- returns 'y' for 'x', 'width' for 'height', etc.
-- @param idx An index table that defines whether horzintal or vertical arrangement will be
-- calculated. See regular_index and switched_index tables.
-- @param bounds The geometry of the bounds for the layout.
-- @param widgets The table of the widgets to layout, can be nested.
-- @param screen The screen of the wibox.
-- @return A table of geometries of all the widgets.
function linear_common.fixed(idx, bounds, widgets, screen)
    -- set bounds width and height to what is preset in the widgets table (if there is something)
    -- we don't need to use idx here since we're treating both directions the same way
    if widgets.width and widgets.width < bounds.width then
        bounds.width = widgets.width
    end
    if widgets.height and widgets.height < bounds.height then
        bounds.height = widgets.height
    end

    -- the table for the geometries which will be returned
    -- we clone the bounds to the 'total' attribute. bounds are used to keep the free space
    -- throughout this function. at the end, 'total' is modified to represent the space taken
    -- by all widgets
    local geometries = {total = clone(bounds)}
    -- the height of the heighest widget, will be the height of the total space taken
    local maxh = 0

    for _, v in ipairs(widgets) do
        if type(v) == "table" or type(v) == "widget" then
            local m = margins[v]
            -- we can shrink the bounds by the horizontal margins right now, they affect our free
            -- space directly (vertical don't, they are different for every item in 'widgets')
            bounds[idx.width] = bounds[idx.width] - m[idx.left] - m[idx.right]
            bounds[idx.x] = bounds[idx.x] + m[idx.left]

            if type(v) == "table" then
                -- create new bounds for the table and shrink it by the vertical margins
                local t_bounds = clone(bounds)
                t_bounds[idx.height] = t_bounds[idx.height] - m[idx.top] - m[idx.bottom]
                t_bounds[idx.y] = t_bounds[idx.y] + m[idx.top]

                -- backup the width and height of the table so we can restore it
                local t_width = v.width
                local t_height = v.height

                -- if the 'widgets' table has height set and the table itself doesn't, we set it
                v[idx.height] = v[idx.height] or widgets[idx.height]

                -- call the layout function recursively on this table
                local layout = v.layout or layout.default
                local g = layout(t_bounds, v, screen)

                -- restore the table's original width and height
                v.width = t_width
                v.height = t_height

                -- subtract the space taken by the table from our bounds
                bounds[idx.width] = bounds[idx.width] - g.total[idx.width]
                -- we only move the 'x' coord if the taken space is on the left side of our bounds
                if g.total[idx.x] == bounds[idx.x] then
                    bounds[idx.x] = bounds[idx.x] + g.total[idx.width] + m[idx.right]
                end

                -- update the maximum height with this new table
                maxh = max(maxh, g.total[idx.height] + m[idx.top] + m[idx.bottom])

                -- insert all geometries from the table to our geometries
                for _, w in ipairs(g) do
                    insert(geometries, w)
                end

            elseif type(v) == "widget" then
                local g = {x = 0, y = 0, width = 0, height = 0}

                if v.visible then
                    -- get the geometry of the widget
                    g = v:extents(screen)

                    -- resize to fit the height available if requested
                    if v.resize and g.width > 0 and g.height > 0 then
                        local ratio = g[idx.width] / g[idx.height]
                        g[idx.width] = floor(bounds[idx.height] * ratio)
                        g[idx.height] = bounds[idx.height]
                    end

                    -- set the coords, apply the top margin
                    g[idx.y] = bounds[idx.y] + m[idx.top]
                    g[idx.x] = bounds[idx.x]

                    -- limit the width of the widget to what's available
                    g[idx.width] = min(g[idx.width], bounds[idx.width])

                    -- if the 'widgets' table has height set, we set it to the widget
                    g[idx.height] = widgets[idx.height] and
                        (widgets[idx.height] - m[idx.top] - m[idx.bottom]) or g[idx.height]

                    -- limit the height of the widget to what's available
                    g[idx.height] = min(g[idx.height], bounds[idx.height] - m[idx.top] - m[idx.bottom])

                    -- subtract the space taken by the widget from our bounds
                    bounds[idx.width] = bounds[idx.width] - g[idx.width]
                    -- move bounds right by the widget's width
                    bounds[idx.x] = bounds[idx.x] + g[idx.width] + m[idx.right]

                    -- update the maximum height with height of this widget
                    maxh = max(maxh, g[idx.height] + m[idx.top] + m[idx.bottom])
                end

                insert(geometries, g)
            end
        end
    end

    -- calculate the total space taken by the widgets
    geometries.total[idx.width] = geometries.total[idx.width] - bounds[idx.width]
    geometries.total[idx.height] = widgets[idx.height] or maxh
    -- if the bounds are on the left of what was empty in the beginning of this function,
    -- we move the total to the right. this, however, most probably happened cos of rightleft layout
    -- inside 'widgets', and only if there was nothing aligned to the left
    if geometries.total[idx.x] == bounds[idx.x] then
        geometries.total[idx.x] = geometries.total[idx.x] + bounds[idx.width]
    end

    return geometries
end


-- Calculates geometries for flex layouts.
-- This generic function is used for all flex layouts.
-- It is written for horizontal layouts, but by using special index 'idx' to access
-- all the geometry attributes, it is used for vertical layouts too. In that case, 'idx'
-- returns 'y' for 'x', 'width' for 'height', etc.
-- @param idx An index table that defines whether horzintal or vertical arrangement will be
-- calculated. See regular_index and switched_index tables.
-- @param bounds The geometry of the bounds for the layout.
-- @param widgets The table of the widgets to layout, can be nested.
-- @param screen The screen of the wibox.
-- @return A table of geometries of all the widgets.
function linear_common.flex(idx, bounds, widgets, screen)
    -- set bounds width and height to what is preset in the widgets table (if there is something)
    -- we don't need to use idx here since we're treating both directions the same way
    if widgets.width and widgets.width < bounds.width then
        bounds.width = widgets.width
    end
    if widgets.height and widgets.height < bounds.height then
        bounds.height = widgets.height
    end

    -- the table for the geometries which will be returned
    -- we clone the bounds to the 'total' attribute. bounds are used to keep the free space
    -- throughout this function. at the end, 'total' is modified to represent the space taken
    -- by all widgets
    local geometries = {total = clone(bounds)}
    -- the height of the heighest widget, will be the height of the total space taken
    local maxh = 0
    -- the number of widgets/tables in 'widgets' argument
    local n = 0
    -- get the gap or set to 0
    local gap = widgets.gap or 0

    -- count the widgets/tables
    for _, v in ipairs(widgets) do
        if type(v) == "table" or (type(v) == "widget" and v.visible) then
            n = n + 1
        end
    end

    -- calculate the width. these vars keep the floating numbers, while bounds keep the
    -- rounded ones and are set from these on each iteration to ensure proper rounding
    local width = (n > 0) and ((widgets[idx.width] or bounds[idx.width]) - gap * (n - 1)) / n or 0
    local x = bounds[idx.x]

    -- if max_size is set and it is lower than the calculated width, use it
    width = (widgets.max_size and widgets.max_size < width) and widgets.max_size or width

    for _, v in ipairs(widgets) do
        -- someone give me freaking continue
        if type(v) == "widget" and not v.visible then
            insert(geometries, {x = 0, y = 0, width = 0, height = 0})
        elseif type(v) == "widget" or type(v) == "table" then
            -- do the floating magic, calculate real_width which will be set to the geometries
            x = x + width
            local real_width = floor(x - bounds[idx.x] + 0.5)

            local m = margins[v]

            if type(v) == "table" then
                -- create new bounds for the table and shrink it by the margins
                local t_bounds = {}
                t_bounds[idx.x] = bounds[idx.x] + m[idx.left]
                t_bounds[idx.y] = bounds[idx.y] + m[idx.top]
                t_bounds[idx.width] = real_width - m[idx.left] - m[idx.right]
                t_bounds[idx.height] = bounds[idx.height] - m[idx.top] - m[idx.bottom]

                -- backup the width and height of the table so we can restore it
                local t_width = v.width
                local t_height = v.height

                -- set the table's width so it can flex what's inside it
                v[idx.width] = real_width

                -- if the 'widgets' table has height set and the table itself doesn't, we set it
                v[idx.height] = v[idx.height] or widgets[idx.height]

                -- call the layout function recursively on this table
                local layout = v.layout or layout.default
                local g = layout(t_bounds, v, screen)

                -- restore the table's original width and height
                v.width = t_width
                v.height = t_height

                -- update the maximum height with this new table
                maxh = max(maxh, g.total[idx.height] + m[idx.top] + m[idx.bottom])

                for _, v in ipairs(g) do
                    insert(geometries, v)
                end
            elseif type(v) == "widget" then
                local g = v:extents(screen)

                -- resize to fit the width available if requested
                if v.resize and g.width > 0 and g.height > 0 then
                    local ratio = g[idx.height] / g[idx.width]
                    g[idx.height] = real_width * ratio
                end

                -- set the widget geometry
                g[idx.x] = bounds[idx.x] + m[idx.left]
                g[idx.width] = real_width - m[idx.left] - m[idx.right]
                g[idx.y] = bounds[idx.y] + m[idx.top]

                -- if the 'widgets' table has height set, we set it to the widget
                g[idx.height] = widgets[idx.height] and
                    (widgets[idx.height] - m[idx.top] - m[idx.bottom]) or g[idx.height]

                -- limit the height of the widget to what's available
                g[idx.height] = min(g[idx.height], bounds[idx.height] - m[idx.top] - m[idx.bottom])

                -- update the maximum height with height of this widget
                maxh = max(maxh, g[idx.height] + m[idx.top] + m[idx.bottom])

                insert(geometries, g)
            end

            -- update the bounds (move it to the right by the widget's width)
            bounds[idx.width] = bounds[idx.width] - real_width - gap
            x = x + gap
            bounds[idx.x] = floor(x + 0.5)
        end
    end

    -- we have total already from the cloned bounds, just set the height to what we got
    geometries.total[idx.width] = geometries.total[idx.width] - bounds[idx.width]
    geometries.total[idx.height] = widgets[idx.height] or maxh

    return geometries
end

return linear_common

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