feat(tmux): added extra term cmd manipulation functions to tmux module

In the future, these should probably be refactored out into the utils
file beacuse they are the exact same functions as the one in the term
module.

lua/harpoon/tmux.lua

@@ -85,6 +85,16 @@ local function find_terminal(args)
     return window_handle
 end
 
+local function get_first_empty_slot()
+    log.trace("_get_first_empty_slot()")
+    for idx, cmd in pairs(harpoon.get_term_config().cmds) do
+        if cmd == "" then
+            return idx
+        end
+    end
+    return M.get_length() + 1
+end
+
 M.gotoTerminal = function(idx)
     log.trace("tmux: gotoTerminal(): Window:", idx)
     local window_handle = find_terminal(idx)
@@ -139,4 +149,51 @@ M.clear_all = function()
     tmux_windows = {}
 end
 
+M.get_length = function()
+    log.trace("_get_length()")
+    return table.maxn(harpoon.get_term_config().cmds)
+end
+
+M.valid_index = function(idx)
+    if idx == nil or idx > M.get_length() or idx <= 0 then
+        return false
+    end
+    return true
+end
+
+M.emit_changed = function()
+    log.trace("_emit_changed()")
+    if harpoon.get_global_settings().save_on_change then
+        harpoon.save()
+    end
+end
+
+M.add_cmd = function(cmd)
+    log.trace("add_cmd()")
+    local found_idx = get_first_empty_slot()
+    harpoon.get_term_config().cmds[found_idx] = cmd
+    M.emit_changed()
+end
+
+M.rm_cmd = function(idx)
+    log.trace("rm_cmd()")
+    if not M.valid_index(idx) then
+        log.debug("rm_cmd(): no cmd exists for index", idx)
+        return
+    end
+    table.remove(harpoon.get_term_config().cmds, idx)
+    M.emit_changed()
+end
+
+M.set_cmd_list = function(new_list)
+    log.trace("set_cmd_list(): New list:", new_list)
+    for k in pairs(harpoon.get_term_config().cmds) do
+        harpoon.get_term_config().cmds[k] = nil
+    end
+    for k, v in pairs(new_list) do
+        harpoon.get_term_config().cmds[k] = v
+    end
+    M.emit_changed()
+end
+
 return M