---------------------------------------------------------------------------
-- @author Uli Schlachter
-- @author dodo
-- @copyright 2010, 2011 Uli Schlachter, dodo
-- @release @AWESOME_VERSION@
---------------------------------------------------------------------------

local oopango = require("oopango")
local oocairo = require("oocairo")
local base = require("wibox.widget.base")
local beautiful = require("beautiful")
local type = type
local unpack = unpack
local setmetatable = setmetatable
local pairs = pairs

module("wibox.widget.textbox")

local function layout_create(cr)
    if oopango.cairo_layout_create then
        return oopango.cairo_layout_create(cr)
    end
    return oopango.cairo.layout_create(cr)
end

local function layout_update(cr, layout)
    if oopango.cairo_update_layout then
        oopango.cairo_update_layout(cr, layout)
    else
        oopango.cairo.update_layout(cr, layout)
    end
end

local function layout_show(cr, layout)
    if oopango.cairo_show_layout then
        oopango.cairo_show_layout(cr, layout)
    else
        oopango.cairo.show_layout(cr, layout)
    end
end

-- Setup a pango layout for the given textbox and cairo context
local function setup_layout(box, width, height)
    local layout = box._layout
    layout:set_width(oopango.units_from_number(width))
    layout:set_height(oopango.units_from_number(height))
end

--- Draw the given textbox on the given cairo context in the given geometry
function draw(box, wibox, cr, width, height)
    layout_update(cr, box._layout)
    setup_layout(box, width, height)
    local ink, logical = box._layout:get_pixel_extents()
    local offset = 0
    if box._valign == "center" then
        offset = (height - logical.height) / 2
    elseif box._valign == "bottom" then
        offset = height - logical.height
    end
    cr:move_to(0, offset)
    layout_show(cr, box._layout)
end

--- Fit the given textbox
function fit(box, width, height)
    setup_layout(box, width, height)
    local ink, logical = box._layout:get_pixel_extents()
    return logical.width, logical.height
end

-- Return a pango layout which can be used if no cairo context is available
local function get_temp_layout()
    local surface = oocairo.image_surface_create("argb32", 0, 0)
    local cr = oocairo.context_create(surface)
    return layout_create(cr)
end

local temp_layout
-- Test if a text is valid for a textbox. If it isn't, a lua error will be thrown.
local function check_text(text, markup)
    if not temp_layout then
        temp_layout = get_temp_layout()
    end

    if markup then
        temp_layout:set_markup(text)
    else
        temp_layout:set_text(text)
    end
end

--- Set a textbox' text.
-- @param text The text to set. This can contain pango markup (e.g. <b>bold</b>)
function set_markup(box, text)
    check_text(text, true)
    box._layout:set_markup(text)
    box:emit_signal("widget::updated")
end

--- Set a textbox' text.
-- @param text The text to display. Pango markup is ignored and shown as-is.
function set_text(box, text)
    check_text(text, false)
    box._layout:set_text(text)
    box:emit_signal("widget::updated")
end

--- Set a textbox' ellipsize mode.
-- @param mode Where should long lines be shortened? "start", "middle" or "end"
function set_ellipsize(box, mode)
    local allowed = { none = true, start = true, middle = true, ["end"] = true }
    if allowed[mode] then
        box._layout:set_ellipsize(mode)
        box:emit_signal("widget::updated")
    end
end

--- Set a textbox' wrap mode.
-- @param mode Where to wrap? After "word", "char" or "word_char"
function set_wrap(box, mode)
    local allowed = { word = true, char = true, word_char = true }
    if allowed[mode] then
        box._layout:set_wrap(mode)
        box:emit_signal("widget::updated")
    end
end

--- Set a textbox' vertical alignment
-- @param mode Where should the textbox be drawn? "top", "center" or "bottom"
function set_valign(box, mode)
    local allowed = { top = true, center = true, bottom = true }
    if allowed[mode] then
        box._valign = mode
        box:emit_signal("widget::updated")
    end
end

--- Set a textbox' horizontal alignment
-- @param mode Where should the textbox be drawn? "left", "center" or "right"
function set_align(box, mode)
    local allowed = { left = true, center = true, right = true }
    if allowed[mode] then
        box._layout:set_alignment(mode)
        box:emit_signal("widget::updated")
    end
end

--- Set a textbox' font
-- @param font The font description as string
function set_font(box, font)
    box._layout:set_font_description(beautiful.get_font(font))
end

-- Returns a new textbox
local function new()
    local ret = base.make_widget()

    for k, v in pairs(_M) do
        if type(v) == "function" then
            ret[k] = v
        end
    end

    -- Spot the hack: Temporary surface to make pango happy
    ret._layout = get_temp_layout()
    ret:set_ellipsize("end")
    ret:set_wrap("word_char")
    ret:set_valign("center")
    ret:set_align("left")
    ret:set_font()

    return ret
end

setmetatable(_M, { __call = function (_, ...) return new(...) end })

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