-- https://stackoverflow.com/questions/64087640/prevent-content-shrinking-in-awesomewm
-- twily sourced 2024

local base = require("wibox.widget.base")

local layout = {}

-- Calculate the layout.
-- @param context The context in which we are drawn.
-- @param width The available width.
-- @param height The available height.
function layout:layout(context, width, height)
    local result = {}

    local prepend_width, prepend_height = 0, 0
    if self._private.prepend then
        prepend_width, prepend_height = base.fit_widget(self, context, self._private.prepend, width, height)
    end

    local append_width, append_height = 0, 0
    if self._private.append then
        append_width, append_height = base.fit_widget(self, context, self._private.append, width, height)
    end

    local width_remains = self._private.dir == "x" and (width - prepend_width - append_width) or width
    local height_remains = self._private.dir == "y" and (height - prepend_height - append_height) or height

    local main_width, main_height = base.fit_widget(self, context, self._private.main, width_remains, height_remains)

    if self._private.prepend then
        local x, y, w, h = 0, 0, width, height
        if self._private.dir == "x" then
            w = prepend_width
        elseif self._private.dir == "y" then
            h = prepend_height
        end
        table.insert(result, base.place_widget_at(self._private.prepend, x, y, w, h))
    end

    if self._private.main then
        local x, y, w, h = 0, 0, width, height
        if self._private.dir == "x" then
            x = prepend_width
            w = main_width
        elseif self._private.dir == "y" then
            y = prepend_height
            h = main_height
        end
        table.insert(result, base.place_widget_at(self._private.main, x, y, w, h))
    end

    if self._private.append then
        local x, y, w, h = 0, 0, width, height
        if self._private.dir == "x" then
            x = prepend_width + main_width
            w = append_width
        elseif self._private.dir == "y" then
            y = prepend_height + main_height
            h = append_height
        end
        table.insert(result, base.place_widget_at(self._private.append, x, y, w, h))
    end

    return result
end

--- Set the layout's prepend widget.
-- This is the widget which is before the main widget
-- @property prepend
-- @tparam widget prepend
-- @propemits true false

function layout:set_prepend(widget)
    if self._private.prepend == widget then
        return
    end
    self._private.prepend = widget
    self:emit_signal("widget::layout_changed")
    self:emit_signal("property::prepend", widget)
end

--- Set the layout's main widget. This is the centered one.
-- @property main
-- @tparam widget main
-- @propemits true false

function layout:set_main(widget)
    if self._private.main == widget then
        return
    end
    self._private.main = widget
    self:emit_signal("widget::layout_changed")
    self:emit_signal("property::main", widget)
end

--- Set the layout's append widget.
-- This is the widget which is after the main widget
-- @property append
-- @tparam widget append
-- @propemits true false

function layout:set_append(widget)
    if self._private.append == widget then
        return
    end
    self._private.append = widget
    self:emit_signal("widget::layout_changed")
    self:emit_signal("property::append", widget)
end

for _, prop in ipairs {"prepend", "main", "append" } do
    layout["get_"..prop] = function(self)
        return self._private[prop]
    end
end

function layout:get_children()
    return gears.table.from_sparse {self._private.prepend, self._private.main, self._private.append}
end

function layout:set_children(children)
    self:set_prepend(children[1])
    self:set_main(children[2])
    self:set_append(children[3])
end

-- Fit the layout into the given space. The layout will
-- ask for the sum of the sizes of its sub-widgets in its direction
-- and the largest sized sub widget in the other direction.
-- @param context The context in which we are fit.
-- @param orig_width The available width.
-- @param orig_height The available height.
function layout:fit(context, orig_width, orig_height)
    local used_in_dir = 0
    local used_in_other = 0

    for _, v in pairs{self._private.prepend, self._private.main, self._private.append} do
        local w, h = base.fit_widget(self, context, v, orig_width, orig_height)

        local max = self._private.dir == "y" and w or h
        if max > used_in_other then
            used_in_other = max
        end

        used_in_dir = used_in_dir + (self._private.dir == "y" and h or w)
    end

    if self._private.dir == "y" then
        return used_in_other, used_in_dir
    end
    return used_in_dir, used_in_other
end

function layout:reset()
    for _, v in pairs({ "prepend", "main", "append" }) do
        self[v] = nil
    end
    self:emit_signal("widget::layout_changed")
end

local function get_layout(dir, prepend, main, append)
    local ret = base.make_widget(nil, nil, {enable_properties = true})
    ret._private.dir = dir

    for k, v in pairs(layout) do
        if type(v) == "function" then
            rawset(ret, k, v)
        end
    end

    ret:set_prepend(prepend)
    ret:set_main(main)
    ret:set_append(append)

    -- The layout allow set_children to have empty entries
    ret.allow_empty_widget = true

    return ret
end

--- Returns a new horizontal layout. This layout can display up to three widgets.
-- :set_prepend() sets a widget with a fixed size at the beginning.
-- :set_append() sets a widget with a fixed size at the end.
-- :set_main() sets a widget which shrink if their is not enough space.
-- @tparam[opt] widget prepend Widget to be put to the beginning.
-- @tparam[opt] widget main Widget to be put to the middle.
-- @tparam[opt] widget append Widget to be put to the end.
function layout.horizontal(prepend, main, append)
    local ret = get_layout("x", prepend, main, append)
    return ret
end

--- Returns a new vertical layout. This layout can display up to three widgets.
-- :set_prepend() sets a widget with a fixed size at the beginning.
-- :set_append() sets a widget with a fixed size at the end.
-- :set_main() sets a widget which shrink if their is not enough space.
-- @tparam[opt] widget prepend Widget to be put to the beginning.
-- @tparam[opt] widget main Widget to be put to the middle.
-- @tparam[opt] widget append Widget to be put to the end.
function layout.vertical(prepend, main, append)
    local ret = get_layout("y", prepend, main, append)
    return ret
end

return layout