feat: show daily forecast

Each day is also including hourly forecast, but this PR lays the
groundwork by talking to the right endpoint.

Instead of day and night values (like in the old weather-widget) I'm
showing min and max temperature as forecasted here.

Signed-off-by: André Jaenisch <andre.jaenisch@posteo.de>

weather-api-widget/README.md

@@ -18,6 +18,7 @@ following config parameters:
 | units | `metric` | `metric` for celsius, `imperial` for fahrenheit |
 | icon_pack_name | `weather-underground-icons` | Name of the icon pack, could be `weather-underground-icon` or `VitalyGorbachev` or create your own, more details below |
 | icons_extension | `.png` | File extension of icons in the pack |
+| show_forecast | false | Show forecast for next three days |
 | timeout | 120 | How often in seconds the widget refreshes |
 
 ### Icons:

weather-api-widget/weather.lua

@@ -174,13 +174,16 @@ local function worker(user_args)
     local both_units_widget = args.both_units_widget or false
     local icon_pack_name = args.icons or 'weather-underground-icons'
     local icons_extension = args.icons_extension or '.png'
+    local show_forecast = args.show_forecast or false
     local timeout = args.timeout or 120
 
     local ICONS_DIR = WIDGET_DIR .. '/icons/' .. icon_pack_name .. '/'
-        local weather_api =
+    -- Forecast endpoint includes current. I could map show_forecast to days here.
-        ('https://api.weatherapi.com/v1/current.json' ..
+    -- Currently overfetching but only showing when opting in.
+    local weather_api =
+        ('https://api.weatherapi.com/v1/forecast.json' ..
             '?q=' .. coordinates[1] .. ',' .. coordinates[2] .. '&key=' .. api_key ..
-            '&units=' .. units .. '&lang=' .. LANG)
+            '&units=' .. units .. '&lang=' .. LANG .. '&days=3')
 
     weather_widget = wibox.widget {
         {
@@ -301,6 +304,66 @@ local function worker(user_args)
         end
     }
 
+    local forecast_widget = {
+        forced_width = 300,
+        layout = wibox.layout.flex.horizontal,
+        update = function(self, forecast)
+            local count = #self
+            for i = 0, count do self[i] = nil end
+            for i, day in ipairs(forecast) do
+                -- Free plan allows forecast for up to three days, each with hours
+                if i > 3 then break end
+                local day_forecast = wibox.widget {
+                    {
+                        text = os.date('%a', tonumber(day.date_epoch)),
+                        align = 'center',
+                        font = font_name .. ' 9',
+                        widget = wibox.widget.textbox
+                    },
+                    {
+                        {
+                            {
+                                image = ICONS_DIR .. icon_map[day.day.condition.code] .. icons_extension,
+                                resize = true,
+                                forced_width = 48,
+                                forced_height = 48,
+                                widget = wibox.widget.imagebox
+                            },
+                            align = 'center',
+                            layout = wibox.container.place
+                        },
+                        {
+                            text = day.day.condition.text,
+                            font = font_name .. ' 8',
+                            align = 'center',
+                            forced_height = 50,
+                            widget = wibox.widget.textbox
+                        },
+                        layout = wibox.layout.fixed.vertical
+                    },
+                    {
+                        {
+                            text = gen_temperature_str(day.day.mintemp_c, '%.0f', false, units),
+                            align = 'center',
+                            font = font_name .. ' 9',
+                            widget = wibox.widget.textbox
+                        },
+                        {
+                            text = gen_temperature_str(day.day.maxtemp_c, '%.0f', false, units),
+                            align = 'center',
+                            font = font_name .. ' 9',
+                            widget = wibox.widget.textbox
+                        },
+                        layout = wibox.layout.fixed.vertical
+                    },
+                    spacing = 8,
+                    layout = wibox.layout.fixed.vertical
+                }
+                table.insert(self, day_forecast)
+            end
+        end
+    }
+
     local function update_widget(widget, stdout, stderr)
         if stderr ~= '' then
             if not warning_shown then
@@ -347,6 +410,12 @@ local function worker(user_args)
             layout = wibox.layout.fixed.vertical
         }
 
+
+        if show_forecast then
+            forecast_widget:update(result.forecast.forecastday)
+            table.insert(final_widget, forecast_widget)
+        end
+
         weather_popup:setup({
             {
                 final_widget,