From 63ed12fe2225d0de1c1939fe2da33557852fb98f Mon Sep 17 00:00:00 2001
From: BuckarooBanzay <BuckarooBanzay@users.noreply.github.com>
Date: Mon, 12 Aug 2024 07:24:28 +0200
Subject: [PATCH] save / load

---
 data.lua                   | 17 +++++++++--
 integrations/advtrains.lua | 58 ++++++++++++++++++++++++++++----------
 2 files changed, 57 insertions(+), 18 deletions(-)

diff --git a/data.lua b/data.lua
index e75ec8f..13a793a 100644
--- a/data.lua
+++ b/data.lua
@@ -31,16 +31,27 @@ function mapsync.load_data(key)
     return value
 end
 
+-- returns the path of the data file, nil if not available
+function mapsync.get_data_file_path(key)
+    local data_backend_def = mapsync.get_data_backend()
+    if not data_backend_def then
+        -- no data backend defined
+        return
+    end
+
+    return data_backend_def.path .. "/" .. key
+end
+
 -- returns a file to write to in the data-storage, nil if not available
 function mapsync.get_data_file(key, mode)
     -- default to read
     mode = mode or "r"
 
-    local data_backend_def = mapsync.get_data_backend()
-    if not data_backend_def then
+    local path = mapsync.get_data_file_path(key)
+    if not path then
         -- no data backend defined
         return
     end
 
-    return global_env.io.open(data_backend_def.path .. "/" .. key, mode)
+    return global_env.io.open(path, mode)
 end
\ No newline at end of file
diff --git a/integrations/advtrains.lua b/integrations/advtrains.lua
index af8abd7..d5ad79c 100644
--- a/integrations/advtrains.lua
+++ b/integrations/advtrains.lua
@@ -1,3 +1,7 @@
+-- advtrains compat
+-- saves a snapshot of the advtrains-data with the `/mapsync_save_advtrains` command
+-- loads the snapshot if available on startup, defaults to the worldfolder if no snapshot found
+
 -- sanity checks
 assert(type(advtrains.load_version_4) == "function")
 assert(type(advtrains.ndb.save_callback) == "function")
@@ -11,34 +15,36 @@ assert(type(advtrains.fpath) == "string")
 -- local old_advtrains_read_component = advtrains.read_component
 function advtrains.read_component(name)
     assert(name == "version")
+    -- currently supported version
     return 4
 end
 
 -- local old_advtrains_save_component = advtrains.save_component
-function advtrains.save_component()
-    -- no-op
+function advtrains.save_component(name)
+    assert(name == "version")
 end
 
+-- load from data- or world-path
 local old_load_atomic = serialize_lib.load_atomic
 function serialize_lib.load_atomic(filename, load_callback)
+    local relpath = string.sub(filename, #advtrains.fpath + 2)
     print(dump({
         fn = "serialize_lib.load_atomic",
         filename = filename,
         fpath = advtrains.fpath,
-        relpath = string.sub(filename, #advtrains.fpath + 2)
+        relpath = relpath
     }))
-    return old_load_atomic(filename, load_callback)
-end
 
-local old_save_atomic_multiple = serialize_lib.save_atomic_multiple
-function serialize_lib.save_atomic_multiple(parts_table, filename_prefix, callback_table, config)
-    print(dump({
-        fn = "serialize_lib.save_atomic_multiple",
-        parts_table = parts_table,
-        filename_prefix = filename_prefix,
-        config = config
-    }))
-    return old_save_atomic_multiple(parts_table, filename_prefix, callback_table, config)
+    local data_file = mapsync.get_data_file("advtrains_" .. relpath)
+    if data_file then
+        -- data-snapshot available, load it
+        -- TODO: create a timestamp and load only if a newer snapshot if found
+        local data_path = mapsync.get_data_file_path("advtrains_" .. relpath)
+        return old_load_atomic(data_path, load_callback)
+    else
+        -- no data snapshot available, load default from world-folder
+        return old_load_atomic(filename, load_callback)
+    end
 end
 
 local advtrains_parts = {"atlatc.ls", "interlocking.ls", "core.ls", "lines.ls", "ndb4.ls"}
@@ -46,9 +52,31 @@ local advtrains_parts = {"atlatc.ls", "interlocking.ls", "core.ls", "lines.ls",
 minetest.register_chatcommand("mapsync_save_advtrains", {
     privs = { mapsync = true },
     func = function()
+        if not mapsync.get_data_backend() then
+            return false, "no data-backend configured"
+        end
+
+        -- save advtrains data first and remove players from wagons
+        local remove_players_from_wagons = true
+        advtrains.save(remove_players_from_wagons)
+
+        -- copy files to data-directory
+        local count = 0
         for _, part in ipairs(advtrains_parts) do
             local path = advtrains.fpath .. "_" .. part
-            print(path)
+            local src = io.open(path, "rb")
+            if not src then
+                return false, "open failed for '" .. path .. "'"
+            end
+
+            local dst = mapsync.get_data_file("advtrains_" .. part, "wb")
+            local data = src:read("*all")
+            count = count + #data
+            dst:write(data)
+            dst:close()
+            src:close()
         end
+
+        return true, "saved " .. count .. " bytes of advtrains data"
     end
 })
\ No newline at end of file