---------------------------------------------------------------------------
--- Popup widget which shows current hotkeys and their descriptions.
--
-- @author Yauheni Kirylau <yawghen@gmail.com>
-- @copyright 2014-2015 Yauheni Kirylau
-- @release @AWESOME_VERSION@
-- @module awful.hotkeys_popup.widget
---------------------------------------------------------------------------

local capi = {
    screen = screen,
    client = client,
    keygrabber = keygrabber,
}
local awful = require("awful")
local wibox = require("wibox")
local beautiful = require("beautiful")
local dpi = beautiful.xresources.apply_dpi
local compute_textbox_width = require("menubar").utils.compute_textbox_width


-- Stripped copy of this module https://github.com/copycat-killer/lain/blob/master/util/markup.lua:
local markup = {}
-- Set the font.
function markup.font(font, text)
    return '<span font="'    .. tostring(font)    .. '">' .. tostring(text) ..'</span>'
end
-- Set the foreground.
function markup.fg(color, text)
    return '<span foreground="' .. tostring(color) .. '">' .. tostring(text) .. '</span>'
end
-- Set the background.
function markup.bg(color, text)
    return '<span background="' .. tostring(color) .. '">' .. tostring(text) .. '</span>'
end


local widget = {
    title_font = "Monospace Bold 9",
    description_font = "Monospace 8",
    width = dpi(1200),
    height = dpi(800),
    border_width = beautiful.border_width or dpi(2),
    modifiers_color = beautiful.bg_minimize or "#555555",
    group_margin = dpi(6),
    group_rules = {},
    additional_hotkeys = {},
    labels = {
        Mod4="Super",
        Mod1="Alt",
        Escape="Esc",
        Insert="Ins",
        Delete="Del",
        Backspace="BackSpc",
        Return="Enter",
        Next="PgDn",
        Prior="PgUp",
        ['#108']="Alt Gr",
        Left='←',
        Up='↑',
        Right='→',
        Down='↓',
        ['#67']="F1",
        ['#68']="F2",
        ['#69']="F3",
        ['#70']="F4",
        ['#71']="F5",
        ['#72']="F6",
        ['#73']="F7",
        ['#74']="F8",
        ['#75']="F9",
        ['#76']="F10",
        ['#95']="F11",
        ['#96']="F12",
        ['#10']="1",
        ['#11']="2",
        ['#12']="3",
        ['#13']="4",
        ['#14']="5",
        ['#15']="6",
        ['#16']="7",
        ['#17']="8",
        ['#18']="9",
        ['#19']="0",
        ['#20']="-",
        ['#21']="=",
        Control="Ctrl"
    },
}

--- Don't show hotkeys without descriptions.
widget.hide_without_description = true

--- Merge hotkey records into one if they have the same modifiers and
-- description.
widget.merge_duplicates = true


local cached_wiboxes = {}
local cached_awful_keys = nil
local colors_counter = {}
local colors = beautiful.xresources.get_current_theme()
local group_list = {}


local function get_next_color(id)
    id = id or "default"
    if colors_counter[id] then
        colors_counter[id] = math.fmod(colors_counter[id] + 1, 15) + 1
    else
        colors_counter[id] = 1
    end
    return colors["color"..tostring(colors_counter[id], 15)]
end


local function join_plus_sort(modifiers)
    if #modifiers<1 then return "none" end
    table.sort(modifiers)
    return table.concat(modifiers, '+')
end


local function add_hotkey(key, data, target)
    if widget.hide_without_description and not data.description then return end

    local readable_mods = {}
    for _, mod in ipairs(data.mod) do
        table.insert(readable_mods, widget.labels[mod] or mod)
    end
    local joined_mods = join_plus_sort(readable_mods)

    local group = data.group or "none"
    group_list[group] = true
    if not target[group] then target[group] = {} end
    local new_key = {
        key = (widget.labels[key] or key),
        mod = joined_mods,
        description = data.description
    }
    local index = data.description or "none"  -- or use its hash?
    if not target[group][index] then
        target[group][index] = new_key
    else
        if widget.merge_duplicates and joined_mods == target[group][index].mod then
            target[group][index].key = target[group][index].key .. "/" .. new_key.key
        else
            while target[group][index] do
                index = index .. " "
            end
            target[group][index] = new_key
        end
    end
end


local function sort_hotkeys(target)
    -- @TODO: add sort by 12345qwertyasdf etc
    for group, _ in pairs(group_list) do
        if target[group] then
            local sorted_table = {}
            for _, key in pairs(target[group]) do
                table.insert(sorted_table, key)
            end
            table.sort(
                sorted_table,
                function(a,b) return (a.mod or '')..a.key<(b.mod or '')..b.key end
            )
            target[group] = sorted_table
        end
    end
end


local function import_awful_keys()
    if cached_awful_keys then
        return
    end
    cached_awful_keys = {}
    for _, data in pairs(awful.key.hotkeys) do
        add_hotkey(data.key, data, cached_awful_keys)
    end
    sort_hotkeys(cached_awful_keys)
end


local function group_label(group, color)
    local textbox = wibox.widget.textbox(
        markup.font(widget.title_font,
            markup.bg(
                color or (widget.group_rules[group] and
                    widget.group_rules[group].color or get_next_color("group_title")
                ),
                markup.fg(beautiful.bg_normal or "#000000", " "..group.." ")
            )
        )
    )
    local margin = wibox.layout.margin()
    margin:set_widget(textbox)
    margin:set_top(widget.group_margin)
    return margin
end

local function create_wibox(s, available_groups)
    local wa = capi.screen[s].workarea
    local height = (widget.height < wa.height) and widget.height or
        (wa.height - widget.border_width * 2)
    local width = (widget.width < wa.width) and widget.width or
        (wa.width - widget.border_width * 2)

    -- arrange hotkey groups into columns
    local line_height = beautiful.get_font_height(widget.title_font)
    local group_label_height = line_height + widget.group_margin
    -- -1 for possible pagination:
    local max_height_px = height - group_label_height
    local column_layouts = {}
    for _, group in ipairs(available_groups) do
        local keys = cached_awful_keys[group] or widget.additional_hotkeys[group]
        local joined_descriptions = ""
        for i, key in ipairs(keys) do
            joined_descriptions = joined_descriptions .. key.description .. (i~=#keys and "\n" or "")
        end
        -- +1 for group label:
        local items_height = awful.util.linecount(joined_descriptions) * line_height + group_label_height
        local current_column
        local available_height_px = max_height_px
        local add_new_column = true
        for i, column in ipairs(column_layouts) do
            if ((column.height_px + items_height) < max_height_px) or
                (i == #column_layouts and column.height_px < max_height_px / 2)
            then
                current_column = column
                add_new_column = false
                available_height_px = max_height_px - current_column.height_px
                break
            end
        end
        local overlap_leftovers
        if items_height > available_height_px then
            local new_keys = {}
            overlap_leftovers = {}
            -- +1 for group title and +1 for possible hyphen (v):
            local available_height_items = (available_height_px - group_label_height*2) / line_height
            for i=1,#keys do
                table.insert(((i<available_height_items) and new_keys or overlap_leftovers), keys[i])
            end
            keys = new_keys
            table.insert(keys, {key=markup.fg(widget.modifiers_color, "▽"), description=""})
        end
        if not current_column then
            current_column = {layout=wibox.layout.fixed.vertical()}
        end
        current_column.layout:add(group_label(group))

        local function insert_keys(_keys, _add_new_column)
            local max_label_width = 0
            local max_label_content = ""
            local joined_labels = ""
            for i, key in ipairs(_keys) do
                local length = string.len(key.key or '') + string.len(key.description or '')
                local modifiers = key.mod
                if not modifiers or modifiers == "none" then
                    modifiers = ""
                else
                    length = length + string.len(modifiers) + 1 -- +1 for "+" character
                    modifiers = markup.fg(widget.modifiers_color, modifiers.."+")
                end
                local rendered_hotkey = markup.font(widget.title_font,
                    modifiers .. (key.key or "") .. " "
                ) .. markup.font(widget.description_font,
                    key.description or ""
                )
                if length > max_label_width then
                    max_label_width = length
                    max_label_content = rendered_hotkey
                end
                joined_labels = joined_labels .. rendered_hotkey .. (i~=#_keys and "\n" or "")
                end
            current_column.layout:add(wibox.widget.textbox(joined_labels))
            local max_width = compute_textbox_width(wibox.widget.textbox(max_label_content), s) +
                                                widget.group_margin
            if not current_column.max_width or max_width > current_column.max_width then
                current_column.max_width = max_width
            end
            -- +1 for group label:
            current_column.height_px = (current_column.height_px or 0) +
                awful.util.linecount(joined_labels)*line_height + group_label_height
            if _add_new_column then
                table.insert(column_layouts, current_column)
            end
        end

        insert_keys(keys, add_new_column)
        if overlap_leftovers then
            current_column = {layout=wibox.layout.fixed.vertical()}
            insert_keys(overlap_leftovers, true)
        end
    end

    -- arrange columns into pages
    local available_width_px = width
    local pages = {}
    local columns = wibox.layout.fixed.horizontal()
    for _, item in ipairs(column_layouts) do
        if item.max_width > available_width_px then
            columns.widgets[#columns.widgets]['widget']:add(
                group_label("PgDn - Next Page", beautiful.fg_normal)
            )
            table.insert(pages, columns)
            columns = wibox.layout.fixed.horizontal()
            available_width_px = width - item.max_width
            local old_widgets = item.layout.widgets
            item.layout.widgets = {group_label("PgUp - Prev Page", beautiful.fg_normal)}
            awful.util.table.merge(item.layout.widgets, old_widgets)
        else
            available_width_px = available_width_px - item.max_width
        end
        local column_margin = wibox.layout.margin()
        column_margin:set_widget(item.layout)
        column_margin:set_left(widget.group_margin)
        columns:add(column_margin)
    end
    table.insert(pages, columns)

    local mywibox = wibox({
        ontop = true,
        opacity = beautiful.notification_opacity or 1,
        border_width = widget.border_width,
        border_color = beautiful.fg_normal,
    })
    mywibox:geometry({
        x = wa.x + math.floor((wa.width - width - widget.border_width*2) / 2),
        y = wa.y + math.floor((wa.height - height - widget.border_width*2) / 2),
        width = width,
        height = height,
    })
    mywibox:set_widget(pages[1])
    mywibox:buttons(awful.util.table.join(
            awful.button({ }, 1, function () mywibox.visible=false end),
            awful.button({ }, 3, function () mywibox.visible=false end)
    ))

    local widget_obj = {}
    widget_obj.current_page = 1
    widget_obj.wibox = mywibox
    function widget_obj:page_next()
        if self.current_page == #pages then return end
        self.current_page = self.current_page + 1
        self.wibox:set_widget(pages[self.current_page])
    end
    function widget_obj:page_prev()
        if self.current_page == 1 then return end
        self.current_page = self.current_page - 1
        self.wibox:set_widget(pages[self.current_page])
    end
    function widget_obj:show()
        self.wibox.visible = true
    end
    function widget_obj:hide()
        self.wibox.visible = false
    end

    return widget_obj
end


--- Show popup with hotkeys help.
-- @tparam[opt] client c Client.
-- @tparam[opt] screen s Screen.
function widget.show_help(c, s)
    import_awful_keys()
    c = c or capi.client.focus
    s = s or (c and c.screen or awful.screen.focused())

    local available_groups = {}
    for group, _ in pairs(group_list) do
        local need_match
        for group_name, data in pairs(widget.group_rules) do
            if group_name==group and (
                data.rule or data.rule_any or data.except or data.except_any
            ) then
                if not c or not awful.rules.matches(c, {
                    rule=data.rule,
                    rule_any=data.rule_any,
                    except=data.except,
                    except_any=data.except_any
                }) then
                    need_match = true
                    break
                end
            end
        end
        if not need_match then table.insert(available_groups, group) end
    end

    local joined_groups = join_plus_sort(available_groups)
    if not cached_wiboxes[s] then
        cached_wiboxes[s] = {}
    end
    if not cached_wiboxes[s][joined_groups] then
        cached_wiboxes[s][joined_groups] = create_wibox(s, available_groups)
    end
    local help_wibox = cached_wiboxes[s][joined_groups]
    help_wibox:show()

    return capi.keygrabber.run(function(_, key, event)
        if event == "release" then return end
        if key then
            if key == "Next" then
                help_wibox:page_next()
            elseif key == "Prior" then
                help_wibox:page_prev()
            else
                capi.keygrabber.stop()
                help_wibox:hide()
            end
        end
    end)
end


--- Add hotkey descriptions for third-party applications.
-- @tparam table hotkeys Table with bindings,
-- see `awful.hotkeys_popup.key.vim` as an example.
function widget.add_hotkeys(hotkeys)
    for group, bindings in pairs(hotkeys) do
        for _, binding in ipairs(bindings) do
            local modifiers = binding.modifiers
            local keys = binding.keys
            for key, description in pairs(keys) do
                add_hotkey(key, {
                    mod=modifiers,
                    description=description,
                    group=group},
                widget.additional_hotkeys
            )
            end
        end
    end
    sort_hotkeys(widget.additional_hotkeys)
end


return widget

-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80