lua submenus add a way to dynamically add items

updated example script and renamed some functions as well

fixed bug in printtable cursor position if greater than maxlines for the
screen would reset to item 1

now we move the list start and select it
(and try to center it on the screen)

fixed a few bugs in the add_menu code

Change-Id: I01dead0481ef2e925af8b4cc6c14e36c2859dbba

3 files changed, 139 insertions, 50 deletions

diff --git a/apps/plugins/lua/include_lua/printsubmenu.lua b/apps/plugins/lua/include_lua/printsubmenu.lua
index 3c61b5fda8..f4b93db98d 100644
--- a/apps/plugins/lua/include_lua/printsubmenu.lua
+++ b/apps/plugins/lua/include_lua/printsubmenu.lua
@@ -21,15 +21,31 @@
  ****************************************************************************/
 ]]
 if not rb.lcd_framebuffer then rb.splash(rb.HZ, "No Support!") return nil end
+--GLOBALS
 menu_ctx = {}
+submenu_insert = table.insert
+submenu_remove = table.remove
+
 local last_ctx = false
 local p_settings
+local function empty_fn() end
 
 --[[root menu tables
 expanded menus get inserted / removed
-and context menus replace them but never overwritten
-unless you want a new root menu
+and context menus replace them but unless you
+want a new root menu they are never overwritten
+func_t functions get 3 variables passed by the menu_system
+func_t[i] =function sample(i, menu_t, func_t]
+this function gets run on user selection
+for every function in func_t:
+'i' is the selected item
+'menu_t' is the current strings table
+'func_t' is the current function table
+
+menu_t[i] will returnm the text of the item user selected and
+func_t[i] will return the function we are currently in
 ]]
+
 menu_t = {}
 func_t = {}
 
@@ -110,16 +126,9 @@ local function dpad(x, xi, xir, y, yi, yir, timeout, overflow, selected)
     return cancel, select, x_chg, x, y_chg, y, 0xffff
 end -- dpad
 
-
-
-local function menu_set_defaults(settings, ctx)
-    p_settings = settings or {wrap = true, hasheader = true, justify = "left", dpad_fn = dpad}
-    menu_ctx = ctx or {collapse_fn = {}, lv = 0, update = false, start = 1}
-end
-
 local function ctx_loop()
     local loopfn = ctx_loop
-    ctx_loop = function() end --prevent another execution
+    ctx_loop = empty_fn() --prevent another execution
     local mt, ft = get_menu()
     local i
     repeat
@@ -130,25 +139,23 @@ local function ctx_loop()
     ctx_loop = loopfn --restore for another run
 end
 
-function get_menu()
-    return menu_t, func_t
-end
-
+--[[ push_ctx() save surrent menu and load another ]]
 local function push_ctx(new_getmenu)
     last_ctx = last_ctx or {}
-    table.insert(last_ctx, menu_ctx)
+    submenu_insert(last_ctx, menu_ctx)
     menu_ctx.getmenu = get_menu
     menu_ctx.settings = p_settings
     --menu_ctx is a new variable after this point
-    menu_set_defaults()
+    submenu_set_defaults()
     menu_ctx.update = true
     if type(new_getmenu) == 'function' then
         get_menu = new_getmenu
     end
 end
 
+--[[ pop_ctx() restore last menu ]]
 local function pop_ctx()
-    menu_ctx = table.remove(last_ctx)
+    menu_ctx = submenu_remove(last_ctx)
     if menu_ctx then
         get_menu = menu_ctx.getmenu
         p_settings = menu_ctx.settings
@@ -163,13 +170,17 @@ local function pop_ctx()
     end
 end
 
+--[[ display_context_menu_internal() supplies a new get_menu function that returns
+     the context menu 'user_context_fn' supplied by set_menu()
+     this menu is immediately displayed and when finished will
+     automatically restore the last menu
+]]
 local function display_context_menu_internal(sel)
-
         if sel <= 0 or not menu_ctx.user_context_fn then return false end
-        local parent = get_parent() or 0
+        local parent = submenu_get_parent() or 0
         local user_context_fn = menu_ctx.user_context_fn
-        local function display_context_menu(i, menu_t, func_t)
 
+        local function display_context_menu(i, menu_t, func_t)
             local function new_getmenu()
                 local mt, ft = user_context_fn(parent, i, menu_t, func_t)
                 ft[0] = pop_ctx --set back fn
@@ -179,6 +190,7 @@ local function display_context_menu_internal(sel)
             return true
         end
 
+        --save the current function in closure restore_fn for later
         local funct = func_t[sel]
         local function restore_fn(mt, ft)
             ft[sel] = funct
@@ -192,30 +204,43 @@ local function display_context_menu_internal(sel)
         return true
 end
 
-function get_parent(lv)
-    lv = lv or #menu_ctx.collapse_fn
+--[[ submenu_get_parent() gets the parent of the top most level
+     if lv is supplied it instead gets the parent of that level ]]
+function submenu_get_parent(lv)
+    lv = lv or #menu_ctx.collapse_fn or 1
     collectgarbage("step")
     local t = menu_ctx.collapse_fn[lv] or {}
-    return t[2] or -1
+    return t[2] or -1, lv
 end
 
-function set_menu(mt, ft, user_context_fn, settings)
-    local function empty_fn() end
-    menu_set_defaults(settings)
-    if type(user_context_fn) == 'function' then
-        display_context_menu = display_context_menu_internal
-        menu_ctx.user_context_fn = user_context_fn
-    else
-        display_context_menu = empty_fn
-        menu_ctx.user_context_fn = false
+--[[ submenu_collapse() collapses submenu till level or ROOT is reached ]]
+function submenu_collapse(parent, lv)
+    local lv_out, menu_sz = 0, 0
+    local item_out = -1
+    local items_removed = 0
+    if lv <= #menu_ctx.collapse_fn then
+        repeat
+            local collapse_fn = submenu_remove(menu_ctx.collapse_fn)
+            if collapse_fn then
+                lv_out, item_out, menu_sz = collapse_fn[1](parent, menu_t, func_t)
+                items_removed = items_removed + menu_sz
+            end
+
+        until not collapse_fn or lv >= lv_out
     end
-    p_settings = settings or p_settings
-    menu_t, func_t = mt, ft
-    ctx_loop()
+    return lv_out, item_out, items_removed
 end
 
-function create_sub_menu(lv, mt, ft)
+--[[ submenu_create() supply level of submenu > 0, ROOT is lv 0
+    supply menu strings table and function table
+    closure returned run this function to expand the menu
+]]
+function submenu_create(lv, mt, ft)
     if lv < 1 then error("Level < 1") end
+    if type(mt) ~= 'table' or type(ft) ~= 'table' then
+        error("mt and ft must be tables")
+    end
+
     -- everything in lua is 1 based menu level is no exception
     local lv_tab = string.rep ("\t", lv)
     local function submenu_closure(i, m, f)
@@ -224,7 +249,7 @@ function create_sub_menu(lv, mt, ft)
         local item_in, item_out = i, i
         if lv <= #menu_ctx.collapse_fn then --something else expanded??
             repeat
-                local collapse_fn = table.remove(menu_ctx.collapse_fn)
+                local collapse_fn = submenu_remove(menu_ctx.collapse_fn)
                 if collapse_fn then
                     lv_out, item_out, menusz_out = collapse_fn[1](i, m, f)
                     -- if the item i is below this menu, it needs to shift too
@@ -241,23 +266,49 @@ function create_sub_menu(lv, mt, ft)
         menu_ctx.update = true
         for item, _ in ipairs(mt) do
             i = i + 1
-            table.insert(m, i, lv_tab .. mt[item])
-            table.insert(f, i, ft[item])
+            submenu_insert(m, i, lv_tab .. mt[item])
+            submenu_insert(f, i, ft[item])
         end
 
         local function collapse_closure(i, m, f)
             --creates a closure around lv, start_item and menu_sz
             for j = 1, menu_sz, 1 do
-                table.remove(m, start_item + 1)
-                table.remove(f, start_item + 1)
+                submenu_remove(m, start_item + 1)
+                submenu_remove(f, start_item + 1)
             end
             return lv, start_item, menu_sz
         end
 
-        table.insert(menu_ctx.collapse_fn, lv, {collapse_closure, start_item})
+        submenu_insert(menu_ctx.collapse_fn, lv, {collapse_closure, start_item})
         return true
     end
 
     return submenu_closure
 end
 
+--
+function submenu_set_defaults(settings, ctx)
+    p_settings = settings or {wrap = true, hasheader = true, justify = "left", dpad_fn = dpad}
+    menu_ctx = ctx or {collapse_fn = {}, lv = 0, update = false, start = 1}
+end
+
+--[[ get_menu() returns the ROOT string and fn tables]]
+function get_menu()
+    return menu_t, func_t
+end
+
+--[[ set_menu() set your menu and the menu has now been entered ]]
+function set_menu(mt, ft, user_context_fn, settings)
+
+    submenu_set_defaults(settings)
+    if type(user_context_fn) == 'function' then
+        display_context_menu = display_context_menu_internal
+        menu_ctx.user_context_fn = user_context_fn
+    else
+        display_context_menu = empty_fn
+        menu_ctx.user_context_fn = false
+    end
+    p_settings = settings or p_settings
+    menu_t, func_t = mt, ft
+    ctx_loop()
+end
diff --git a/apps/plugins/lua/include_lua/printtable.lua b/apps/plugins/lua/include_lua/printtable.lua
index bf81c7b060..7a883367b7 100644
--- a/apps/plugins/lua/include_lua/printtable.lua
+++ b/apps/plugins/lua/include_lua/printtable.lua
@@ -336,6 +336,16 @@ function print_table(t, t_count, settings)
 
     table_p = init_position(15, 5)
     line, maxline = _print.opt.area(5, 1, rb.LCD_WIDTH - 10 - sb_width, rb.LCD_HEIGHT - 2)
+
+    if curpos > maxline then
+        local c = maxline / 2
+        start = (start or 1) + curpos - maxline
+        curpos = maxline
+        while start + maxline <= t_count and curpos > c do
+            curpos = curpos - 1
+            start = start + 1
+        end
+    end
     maxline = math.min(maxline, t_count)
 
     -- allow user to start at a position other than the beginning
diff --git a/apps/plugins/lua_scripts/submenu_demo.lua b/apps/plugins/lua_scripts/submenu_demo.lua
index 75fec11979..8eac825474 100644
--- a/apps/plugins/lua_scripts/submenu_demo.lua
+++ b/apps/plugins/lua_scripts/submenu_demo.lua
@@ -13,17 +13,17 @@ end
 local function ITEM_MENU()
 
     local function flung(i, menu_t, func_t)
-        local parent = get_parent() or 0
+        local parent = submenu_get_parent() or 0
         rb.splash(100, "flung " .. (menu_t[parent] or "?"))
     end
 
     local function foo(i, menu_t, func_t)
-        local parent = get_parent() or 0
+        local parent = submenu_get_parent() or 0
         rb.splash(100, "FOO " .. menu_t[parent])
     end
 
     local function far(i, menu_t, func_t)
-        local parent = get_parent() or 0
+        local parent = submenu_get_parent() or 0
         rb.splash(100, "far" .. menu_t[parent])
     end
 
@@ -32,16 +32,44 @@ local function ITEM_MENU()
 end
 
 local function USERITEMS()
+    local lv = 2
+    local mt = {"Item_1", "Item_2", "Item_3"}
+    local ft = {}
 
-        return {"Item_1", "Item_2", "Item_3"},
-               {create_sub_menu(2, ITEM_MENU()), create_sub_menu(2, ITEM_MENU()),
-                create_sub_menu(2, ITEM_MENU()), function() end}
+    local function insert_item(i, name, func) --closure
+        submenu_insert(mt, i, name)
+        submenu_insert(ft, i, func)
+    end
+
+    for i = 1, #mt, 1 do
+        ft[i] = submenu_create(lv, ITEM_MENU())
+    end
+
+    local function add_new(i, menu_t, func_t)
+        local parent, lv = submenu_get_parent(lv - 1)
+        local last = #mt
+        local name = "Item_" .. tostring(last)
+        local func = submenu_create(lv + 1, ITEM_MENU())
+
+        local lv_out, item_out, removed  = submenu_collapse(parent, lv + 1)-- collapse others
+        submenu_collapse(parent, lv) -- collapse the parent
+
+        insert_item(last, name, func)
+
+        func_t[parent](parent, menu_t, func_t) -- reopen parent
+        menu_ctx.start = i - removed
+        return true
+    end
+
+    local next = #mt + 1
+    insert_item(next, "Add New", add_new)
+    return mt, ft
 end
 
 local function MAIN_MENU()
 
     local function go_back(i, m, f)
-        local parent = get_parent() or 0
+        local parent = submenu_get_parent() or 0
         if parent > 0 then
             f[parent](parent, m, f)
         else
@@ -60,7 +88,7 @@ local function MAIN_MENU()
     local ft =  {
         [0]  = go_back, --if user cancels do this function
         [1]  = false, -- shouldn't happen title occupies this slot
-        [2]  = create_sub_menu(1, USERITEMS()),
+        [2]  = submenu_create(1, USERITEMS()),
         [3]  = go_back,
         }
     return mt, ft, get_ctx_menu