--[[
# Clock Rings by Linux Mint (2012) reEdited by Altin.
#
# https://github.com/altinukshini/conky_blue
#
# This script draws percentage meters as rings, and also draws clock hands if you want!
# It is fully customisable; all options are described in the script.
# This script is based off a combination of my clock.lua script and my rings.lua script.
#
# IMPORTANT: If you are using the 'cpu' function, it will cause a segmentation fault if it tries to draw a ring straight away.
#                     The if statement on line 324 uses a delay to make sure that this doesn't happen.
#                     It calculates the length of the delay by the number of updates since Conky started.
#                     Generally, a value of 5s is long enough, so if you update Conky every 1s,
#                     use update_num>5 in that if statement (the default).
#                     If you only update Conky every 2s, you should change it to update_num>3;
#                     conversely if you update Conky every 0.5s, you should use update_num>10.
#                     ALSO, if you change your Conky, is it best to use "killall conky; conky" to update it,
#                     otherwise the update_num will not be reset and you will get an error.
#
# To call this script in Conky, use the following in your conkyrc:
#
#   lua_load ~/.conky/clock01_rings.lua
#   lua_draw_hook_pre clock_rings
#
# Changelog:
#   * v1.0 -->  Original release (30.09.2009)
#   * v1.1p -->   Jpope edit londonali1010 (05.10.2009)
#   * vX 2011mint --> reEdit despot77 (18.02.2011)
#   * vX 2012 --> Altin reEdit (22.07.2012)
#   * Added weather function (Accu Weather)
#   * Added battery monitoring
#   * Syslog monitoring
#   * Running processes monitoring
#   * Rearanged rings
#   * Exctra network functions/monitoring
#   * Changed Fonts
]]

settings_table = {
    {
        -- Edit this table to customise your rings.
        -- You can create more rings simply by adding more elements to settings_table.
        -- "name" is the type of stat to display; you can choose from 'cpu', 'memperc', 'fs_used_perc', 'battery_used_perc'.
        name='time',
        -- "arg" is the argument to the stat type, e.g. if in Conky you would write ${cpu cpu0}, 'cpu0' would be the argument. If you would not use an argument in the Conky variable, use ''.
        arg='%I.%M',
        -- "max" is the maximum value of the ring. If the Conky variable outputs a percentage, use 100.
        max=12,
        -- "bg_colour" is the colour of the base ring.
        bg_colour=0xffffff,
        -- "bg_alpha" is the alpha value of the base ring.
        bg_alpha=0.15,
        -- "fg_colour" is the colour of the indicator part of the ring.
        fg_colour=0xB90004,
        -- "fg_alpha" is the alpha value of the indicator part of the ring.
        fg_alpha=0.3,
        -- "x" and "y" are the x and y coordinates of the centre of the ring, relative to the top left corner of the Conky window.
        x=100, y=175,
        -- "radius" is the radius of the ring.
        radius=50,
        -- "thickness" is the thickness of the ring, centred around the radius.
        thickness=5,
        -- "start_angle" is the starting angle of the ring, in degrees, clockwise from top. Value can be either positive or negative.
        start_angle=0,
        -- "end_angle" is the ending angle of the ring, in degrees, clockwise from top. Value can be either positive or negative, but must be larger than start_angle.
        end_angle=360
    },
    {
        name='battery_percent',
        arg='',
        max=100,
        bg_colour=0xffffff,
        bg_alpha=0.2,
        fg_colour=0xB90004,
        fg_alpha=0.8,
        x=222, y=110,
        radius=27,
        thickness=5,
        start_angle=-90,
        end_angle=270
    },
    {
        name='time',
        arg='%M.%S',
        max=60,
        bg_colour=0xffffff,
        bg_alpha=0.1,
        fg_colour=0xB90004,
        fg_alpha=0.4,
        x=100, y=175,
        radius=66,
        thickness=5,
        start_angle=0,
        end_angle=360
    },
    {
        name='time',
        arg='%S',
        max=60,
        bg_colour=0xffffff,
        bg_alpha=0.1,
        fg_colour=0xB90004,
        fg_alpha=0.6,
        x=100, y=175,
        radius=72,
        thickness=5,
        start_angle=0,
        end_angle=360
    },
    {
        name='time',
        arg='%d',
        max=31,
        bg_colour=0xffffff,
        bg_alpha=0.1,
        fg_colour=0xB90004,
        fg_alpha=0.8,
        x=100, y=175,
        radius=80,
        thickness=5,
        start_angle=-90,
        end_angle=90
    },
    {
        name='time',
        arg='%m',
        max=12,
        bg_colour=0xffffff,
        bg_alpha=0.1,
        fg_colour=0xB90004,
        fg_alpha=1,
        x=100, y=175,
        radius=86,
        thickness=5,
        start_angle=-90,
        end_angle=90
    },
}

-- Use these settings to define the origin and extent of your clock.

clock_r=65

-- "clock_x" and "clock_y" are the coordinates of the centre of the clock, in pixels, from the top left of the Conky window.

clock_x=100
clock_y=175

show_seconds=false -- Change to true if you want the seconds hand

require 'cairo'

function rgb_to_r_g_b(colour, alpha)
    return ((colour / 0x10000) % 0x100) / 255., ((colour / 0x100) % 0x100) / 255., (colour % 0x100) / 255., alpha
end

function window_background(colour, alpha)
    return ((colour / 0x10000) % 0x100) / 255., ((colour / 0x100) % 0x100) / 255., (colour % 0x100) / 255., alpha
end

function draw_ring(cr, t, pt)
    local w, h=conky_window.width, conky_window.height

    local xc, yc, ring_r, ring_w, sa, ea=pt['x'], pt['y'], pt['radius'], pt['thickness'], pt['start_angle'], pt['end_angle']
    local bgc, bga, fgc, fga=pt['bg_colour'], pt['bg_alpha'], pt['fg_colour'], pt['fg_alpha']

    local angle_0=sa*(2*math.pi/360)-math.pi/2
    local angle_f=ea*(2*math.pi/360)-math.pi/2
    local t_arc=t*(angle_f-angle_0)

    -- Draw background ring

    cairo_arc(cr, xc, yc, ring_r, angle_0, angle_f)
    cairo_set_source_rgba(cr, rgb_to_r_g_b(bgc, bga))
    cairo_set_line_width(cr, ring_w)
    cairo_stroke(cr)

    -- Draw indicator ring

    cairo_arc(cr, xc, yc, ring_r, angle_0, angle_0+t_arc)
    cairo_set_source_rgba(cr, rgb_to_r_g_b(fgc, fga))
    cairo_stroke(cr)
end

function draw_clock_hands(cr, xc, yc)
    local secs, mins, hours, secs_arc, mins_arc, hours_arc
    local xh, yh, xm, ym, xs, ys

    secs=os.date("%S")
    mins=os.date("%M")
    hours=os.date("%I")

    secs_arc=(2*math.pi/60)*secs
    mins_arc=(2*math.pi/60)*mins+secs_arc/60
    hours_arc=(2*math.pi/12)*hours+mins_arc/12

    -- Draw hour hand

    xh=xc+0.76*clock_r*math.sin(hours_arc)
    yh=yc-0.72*clock_r*math.cos(hours_arc)
    cairo_move_to(cr, xc, yc)
    cairo_line_to(cr, xh, yh)

    cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND)
    cairo_set_line_width(cr, 5)
    cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 1.0)
    cairo_stroke(cr)

    -- Draw minute hand

    xm=xc+0.98*clock_r*math.sin(mins_arc)
    ym=yc-1.02*clock_r*math.cos(mins_arc)
    cairo_move_to(cr, xc, yc)
    cairo_line_to(cr, xm, ym)

    cairo_set_line_width(cr, 3)
    cairo_stroke(cr)

    -- Draw seconds hand

    if show_seconds then
        xs=xc+1.1*clock_r*math.sin(secs_arc)
        ys=yc-clock_r*math.cos(secs_arc)
        cairo_move_to(cr, xc, yc)
        cairo_line_to(cr, xs, ys)

        cairo_set_line_width(cr, 1)
        cairo_stroke(cr)
    end
end

function conky_clock_rings()
    local function setup_rings(cr, pt)
        local str=''
        local value=0

        str=string.format('${%s %s}', pt['name'], pt['arg'])
        str=conky_parse(str)

        value=tonumber(str)
        if value == 0 and pt['name'] == 'battery_percent' then
            pt['bg_alpha'] = 0
        end
        pct=value/pt['max']

        draw_ring(cr, pct, pt)
    end

    -- Check that Conky has been running for at least 5s

    if conky_window==nil then return end
    local cs=cairo_xlib_surface_create(conky_window.display, conky_window.drawable, conky_window.visual, conky_window.width, conky_window.height)

    local cr=cairo_create(cs)

    local updates=conky_parse('${updates}')
    update_num=tonumber(updates)

    if update_num>5 then
        for i in pairs(settings_table) do

            setup_rings(cr, settings_table[i])
        end
    end

    draw_clock_hands(cr, clock_x, clock_y)
end