rules.lua

-- ttd_util/rules.lua
return function(ttd_util)
      local core, storage = core, core.get_mod_storage()
      local rules = {}

      -- default rules text... -------------------------------------------------
      local default_rules = [[<center>┏━━━━━━━━━━━━━━━━━━━━━━━━━━━┓</center>
<center>┃                 <style size=18><b>Welcome to the</b></style>                 ┃</center>
<center>┃     <style size=18><b><style color=#ca0000>The Technical Difficulties!</style></b></style>     ┃</center>
<center>┗━━━━━━━━━━━━━━━━━━━━━━━━━━━┛</center>

rules...
]]

      local rules_text = storage:get_string("ttd_util_rules_text")
      if rules_text == "" then
            rules_text = default_rules
            storage:set_string("ttd_util_rules_text", rules_text)
      end

      -- Messages -----------------------------------------------------------
      local no_interact_msg =
            "You must agree to the rules to gain the privilege 'interact'. " ..
            "Use /rules when you reconsider."

      local interact_msg =
            "Thank you for agreeing to the rules. " ..
            "You now have the privilege 'interact'."

      local function set_rules_text(new_text)
            rules_text = new_text
            storage:set_string("ttd_util_rules_text", rules_text)
      end

      -- Layout constants ---------------------------------------------------
      local pad, form_w, form_h, button_h = 0.325, 9, 11, 0.85
      local txt_area_pad = 0.15
      local content_w    = form_w - pad * 2
      local content_h    = form_h - (button_h + pad * 3)

      -- Forms --------------------------------------------------------------
      local function get_rules_formspec(player)
            local accepted =
                  player:get_meta():get_string("ttd_util_accepted_rules") == "true"
            local button_w = (form_w - (pad * 3)) / 2

            local fs = {
                  "formspec_version[6]",
                  "size[" .. form_w .. "," .. form_h .. "]",
                  "box[" .. pad .. "," .. pad .. ";" ..
                        content_w .. "," .. content_h .. ";#000000]",
                  "container[" .. (pad + txt_area_pad) .. "," ..
                        (pad + txt_area_pad) .. "]",
                  "hypertext[0,0;" ..
                        (form_w - (pad + txt_area_pad) * 2) .. "," ..
                        (content_h - txt_area_pad * 2) ..
                        ";ttd_util_rules_ht;" ..
                        core.formspec_escape(rules_text) .. "]",
                  "container_end[]",
            }

            local button_y = form_h - (button_h + pad)

            if accepted then
                  local close_x = (form_w - button_w) / 2
                  fs[#fs + 1] =
                        "button_exit[" .. close_x .. "," .. button_y .. ";" ..
                        button_w .. "," .. button_h ..
                        ";ttd_util_rules_close;Close]"
            else
                  fs[#fs + 1] =
                        "style[ttd_util_rules_disagree;bgcolor=red]"
                  fs[#fs + 1] =
                        "button[" .. pad .. "," .. button_y .. ";" ..
                        button_w .. "," .. button_h ..
                        ";ttd_util_rules_disagree;I do not agree!]"
                  fs[#fs + 1] =
                        "style[ttd_util_rules_agree;bgcolor=green]"
                  fs[#fs + 1] =
                        "button[" .. (pad * 2 + button_w) .. "," .. button_y ..
                        ";" .. button_w .. "," .. button_h ..
                        ";ttd_util_rules_agree;I agree]"
            end

            return table.concat(fs)
      end

      local function get_setrules_formspec(current_text)
            local width     = (content_w * 2) + (pad * 3)
            local content_h = form_h - (button_h + pad * 3)
            local button_w  = 3

            local fs = {
                  "formspec_version[6]",
                  "size[" .. width .. "," .. form_h .. "]",
                  "no_prepend[]",
                  "bgcolor[#00000000]",
                  "background9[0,0;" .. width .. "," .. form_h ..
                        ";gui_formbg.png;true;10]",

                  "container[" .. pad .. "," .. (button_h + pad * 2) .. "]",
                  "textarea[0,0;" .. content_w .. "," .. content_h ..
                        ";ttd_util_edit_rules_input;;" ..
                        core.formspec_escape(current_text) .. "]",

                  "box[" .. (content_w + pad) .. ",0;" ..
                        content_w .. "," .. content_h .. ";#000000]",
                  "container[" .. (content_w + pad + txt_area_pad) ..
                        "," .. txt_area_pad .. "]",
                  "hypertext[0,0;" ..
                        (content_w - txt_area_pad * 2) .. "," ..
                        (content_h - txt_area_pad * 2) ..
                        ";ttd_util_edit_rules_preview;" ..
                        core.formspec_escape(current_text) .. "]",
                  "container_end[]",
                  "container_end[]",

                  "image_button[" ..
                        (width - pad - button_w - pad - button_h) .. "," ..
                        pad .. ";" .. button_h .. "," .. button_h ..
                        ";refresh.png;refresh_rules;]",
                  "style[save_rules;bgcolor=green]",
                  "button[" .. (width - pad - button_w) .. "," .. pad ..
                        ";" .. button_w .. "," .. button_h ..
                        ";save_rules;Save]",
                  "button[" .. pad .. "," .. pad .. ";" ..
                        button_w .. "," .. button_h ..
                        ";cancel_rules;Cancel]",
            }

            return table.concat(fs)
      end

      -- Public API ---------------------------------------------------------
      function rules.show_rules(player)
            core.show_formspec(
                  player:get_player_name(),
                  "ttd_util_rules:main",
                  get_rules_formspec(player)
            )
      end

      -- Hooks --------------------------------------------------------------
      core.register_on_newplayer(function(player)
            local name  = player:get_player_name()
            local meta  = player:get_meta()
            local privs = core.get_player_privs(name)

            privs.interact = nil
            core.set_player_privs(name, privs)

            if meta:get_string("ttd_util_accepted_rules") ~= "true" then
                  core.after(0.75, function()
                        rules.show_rules(player)
                  end)
            end
      end)

      core.register_on_joinplayer(function(player)
            local name = player:get_player_name()
            local meta = player:get_meta()
            if meta:get_string("ttd_util_accepted_rules") ~= "true" then
                  local privs = core.get_player_privs(name)
                  privs.interact = nil
                  core.set_player_privs(name, privs)
                  core.after(0.75, function()
                        rules.show_rules(player)
                  end)
            end
      end)

      -- Commands -----------------------------------------------------------
      core.register_chatcommand("rules", {
            description = "Show the server rules",
            func = function(name)
                  local player = core.get_player_by_name(name)
                  if player then
                        rules.show_rules(player)
                  end
            end
      })

      core.register_chatcommand("set_rules", {
            description = "Edit the server rules (admin only)",
            privs = { server = true },
            func = function(name)
                  core.show_formspec(
                        name,
                        "ttd_util_rules:set",
                        get_setrules_formspec(rules_text)
                  )
            end
      })

      -- Field handling -----------------------------------------------------
      core.register_on_player_receive_fields(function(player, formname, fields)
            local name = player:get_player_name()
            local meta = player:get_meta()

            if formname == "ttd_util_rules:main" then
                  if fields.quit then
                        if meta:get_string("ttd_util_accepted_rules") ~= "true" then
                              core.chat_send_player(name, no_interact_msg)
                        end
                        return
                  end

                  if fields.ttd_util_rules_agree then
                        if meta:get_string("ttd_util_accepted_rules") ~= "true" then
                              meta:set_string("ttd_util_accepted_rules", "true")
                              local privs = core.get_player_privs(name)
                              privs.interact = true
                              core.set_player_privs(name, privs)
                              core.chat_send_player(name, interact_msg)
                              core.close_formspec(name, "ttd_util_rules:main")
                        else
                              core.show_formspec(
                                    name,
                                    "ttd_util_rules:main",
                                    get_rules_formspec(player)
                              )
                        end

                  elseif fields.ttd_util_rules_disagree then
                        if meta:get_string("ttd_util_accepted_rules") == "true" then
                              core.show_formspec(
                                    name,
                                    "ttd_util_rules:main",
                                    get_rules_formspec(player)
                              )
                        else
                              core.close_formspec(name, "ttd_util_rules:main")
                              core.chat_send_player(name, no_interact_msg)
                        end
                  end
                  return
            end
            
            if formname == "ttd_util_rules:set" then
                  -- refresh button: re‑open the formspec with updated preview
                  if fields.refresh_rules and fields.ttd_util_edit_rules_input then
                        core.show_formspec(
                              name,
                              "ttd_util_rules:set",
                              get_setrules_formspec(fields.ttd_util_edit_rules_input)
                        )
                        return
                  end

                  -- save button
                  if fields.save_rules and fields.ttd_util_edit_rules_input then
                        set_rules_text(fields.ttd_util_edit_rules_input)
                        core.chat_send_player(name, "Rules updated successfully.")
                        core.close_formspec(name, "ttd_util_rules:set")
                        return
                  end

                  -- cancel button
                  if fields.cancel_rules then
                        core.chat_send_player(name, "Rules edit cancelled.")
                        core.close_formspec(name, "ttd_util_rules:set")
                        return
                  end
            end

      end)

      return rules
end