load overlay widget configuration

plugins/lua/overlay.lua

@@ -1,17 +1,105 @@
 local _ENV = mkmodule('plugins.overlay')
 
+local json = require('json')
+local utils = require('utils')
 local widgets = require('gui.widgets')
 
+local WIDGETS_ENABLED_FILE = 'dfhack-config/overlay/widgets.json'
+local WIDGETS_STATE_DIR = 'dfhack-config/overlay/widgets/'
+
 local widget_db = {} -- map of widget name to state
 local active_hotspot_widgets = {} -- map of widget names to the db entry
 local active_viewscreen_widgets = {} -- map of vs_name to map of w.names -> db
 local active_triggered_screen = nil
 
+local function instantiate_widget(name, config)
+    local provider = config.provider
+    local ok, provider_env = pcall(require, provider)
+    if not ok then
+        ok, provider_env = pcall(require, 'plugins.'..provider)
+    end
+    if not ok then
+        ok, provider_env = pcall(reqscript, provider)
+    end
+    if not ok then
+        dfhack.printerr(
+                ('error loading overlay widget "%s": could not find provider' ..
+                    ' environment "%s"')
+                :format(name, provider))
+        return nil
+    end
+
+    local classname = config.class
+    if not provider_env[classname] then
+        dfhack.printerr(
+                ('error loading overlay widget "%s": could not find class "%s"')
+                :format(name, classname))
+        return nil
+    end
+
+    local frame = {}
+    local pos = utils.assign({x=-1, y=20}, config.pos or {})
+    if pos.x < 0 then frame.r = math.abs(pos.x) - 1 else frame.l = pos.x - 1 end
+    if pos.y < 0 then frame.b = math.abs(pos.y) - 1 else frame.t = pos.y - 1 end
+
+    return provider_env[classname]{frame=frame}
+end
+
+local function normalize_list(element_or_list)
+    if type(element_or_list) == 'table' then return element_or_list end
+    return {element_or_list}
+end
+
+-- allow "short form" to be specified, but use "long form"
+local function normalize_viewscreen_name(vs_name)
+    if vs_name:match('viewscreen_.*st') then return vs_name end
+    return 'viewscreen_' .. vs_name .. 'st'
+end
+
+local function load_widget(name, config, enabled)
+    local widget = instantiate_widget(name, config)
+    if not widget then return end
+    local db_entry = {
+        widget=widget,
+        next_update_ms=widget.overlay_onupdate and 0 or math.huge,
+    }
+    widget_db[name] = db_entry
+    if not enabled then return end
+    if config.hotspot then
+        active_hotspot_widgets[name] = db_entry
+    end
+    for vs_name in ipairs(normalize_list(config.viewscreens)) do
+        vs_name = normalize_viewscreen_name(vs_name)
+        ensure_key(active_viewscreen_widgets, vs_name)[name] = db_entry
+    end
+end
+
+local function load_config(fname)
+    local ok, config = pcall(json.decode_file, fname)
+    return ok and config or {}
+end
+
 function reload()
     widget_db = {}
     active_hotspot_widgets = {}
     active_viewscreen_widgets = {}
     active_triggered_screen = nil
+
+    local enabled_map = load_config(WIDGETS_ENABLED_FILE)
+    for _,fname in ipairs(dfhack.filesystem.listdir(WIDGETS_STATE_DIR)) do
+        local _,_,name = fname:find('^(.*)%.json$')
+        if not name then goto continue end
+        local widget_config = load_config(WIDGETS_STATE_DIR..fname)
+        if not widget_config.provider or not widget_config.class then
+            dfhack.printerr(
+                    ('error loading overlay widget "%s": "provider" and' ..
+                     ' "class" must be specified in %s%s')
+                    :format(name, WIDGETS_STATE_DIR, fname))
+            goto continue
+        end
+        load_widget(name, widget_config, not not enabled_map[name])
+        ::continue::
+    end
 end
 
 -- reduces the next call by a small random amount to introduce jitter into the