---------------------------------------------------------------------------
-- @author Julien Danjou <julien@danjou.info>
-- @copyright 2008 Julien Danjou
-- @release @AWESOME_VERSION@
---------------------------------------------------------------------------

-- Grab environment we need
local hooks = require("awful.hooks")
local util = require("awful.util")
local pairs = pairs
local ipairs = ipairs
local capi =
{
    screen = screen,
    mouse = mouse
}

--- Tag module for awful
module("awful.tag")

-- Private data
local data = {}
data.history = {}
data.history.past = {}
data.history.current = {}

-- History functions
history = {}

--- Compare 2 tables of tags.
-- @param a The first table.
-- @param b The second table of tags.
-- @return True if the tables are identical, false otherwise.
local function compare_select(a, b)
    if not a or not b then
        return false
    end
    -- Quick size comparison
    if #a ~= #b then
        return false
    end
    for ka, va in pairs(a) do
        if b[ka] ~= va.selected then
            return false
        end
    end
    for kb, vb in pairs(b) do
        if a[kb].selected ~= vb then
            return false
        end
    end
    return true
end

--- Update the tag history.
-- @param screen The screen number.
function history.update(screen)
    local curtags = capi.screen[screen]:tags()
    if not compare_select(curtags, data.history.current[screen]) then
        data.history.past[screen] = data.history.current[screen]
        data.history.current[screen] = {}
        for k, v in ipairs(curtags) do
            data.history.current[screen][k] = v.selected
        end
    end
end

-- Revert tag history.
-- @param screen The screen number.
function history.restore(screen)
    local s = screen or capi.mouse.screen
    local tags = capi.screen[s]:tags()
    for k, t in pairs(tags) do
        t.selected = data.history.past[s][k]
    end
end

--- Return a table with all visible tags
-- @param s Screen number.
-- @return A table with all selected tags.
function selectedlist(s)
    local screen = s or capi.mouse.screen
    local tags = capi.screen[screen]:tags()
    local vtags = {}
    for i, t in pairs(tags) do
        if t.selected then
            vtags[#vtags + 1] = t
        end
    end
    return vtags
end

--- Return only the first visible tag.
-- @param s Screen number.
function selected(s)
    return selectedlist(s)[1]
end

--- Set master width factor.
-- @param mwfact Master width factor.
-- @param screen Optional screen number.
function setmwfact(mwfact, screen)
    local t = selected(screen)
    if t then
        t.mwfact = mwfact
    end
end

--- Increase master width factor.
-- @param add Value to add to master width factor.
function incmwfact(add)
    local t = selected()
    if t then
        t.mwfact = t.mwfact + add
    end
end

--- Set the number of master windows.
-- @param nmaster The number of master windows.
function setnmaster(nmaster)
    local t = selected()
    if t then
        t.nmaster = nmaster
    end
end

--- Increase the number of master windows.
-- @param add Value to add to number of master windows.
function incnmaster(add)
    local t = selected()
    if t then
        t.nmaster = t.nmaster + add
    end
end

--- Set number of column windows.
-- @param ncol The number of column.
function setncol(ncol)
    local t = selected()
    if t then
        t.ncol = ncol
    end
end

--- Increase number of column windows.
-- @param add Value to add to number of column windows.
function incncol(add)
    local t = selected()
    if t then
        t.ncol = t.ncol + add
    end
end

--- View no tag.
-- @param Optional screen number.
function viewnone(screen)
    local tags = capi.screen[screen or capi.mouse.screen]:tags()
    for i, t in pairs(tags) do
        t.selected = false
    end
end

--- View a tag by its index.
-- @param i The relative index to see.
-- @param screen Optional screen number.
function viewidx(i, screen)
    local tags = capi.screen[screen or capi.mouse.screen]:tags()
    local sel = selected()
    viewnone()
    for k, t in ipairs(tags) do
        if t == sel then
            tags[util.cycle(#tags, k + i)].selected = true
        end
    end
end

--- View next tag. This is the same as tag.viewidx(1).
function viewnext()
    return viewidx(1)
end

--- View previous tag. This is the same a tag.viewidx(-1).
function viewprev()
    return viewidx(-1)
end

--- View only a tag.
-- @param t The tag object.
function viewonly(t)
    viewnone(t.screen)
    t.selected = true
end

--- View only a set of tags.
-- @param tags A table with tags to view only.
-- @param screen Optional screen number of the tags.
function viewmore(tags, screen)
    viewnone(screen)
    for i, t in pairs(tags) do
        t.selected = true
    end
end

-- Register standards hooks
hooks.arrange.register(history.update)

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