1 files changed, 91 insertions, 0 deletions
diff --git a/Tools/BlockTypePaletteGenerator/Generator.lua b/Tools/BlockTypePaletteGenerator/Generator.lua
new file mode 100644
index 000000000..f33f2b789
--- /dev/null
+++ b/Tools/BlockTypePaletteGenerator/Generator.lua
@@ -0,0 +1,91 @@
+-- lib/lunajson/src/ is not in default Lua package paths
+package.path = 'lib/lunajson/src/?.lua;' .. package.path;
+
+
+--- Prints usage instructions to stdout.
+-- If the optional `message` is passed, output is prepended by message _and_
+-- redirected to stderr.
+function usage(message)
+	if message then
+		io.output(io.stderr);
+		io.write(message, "\n\n");
+	end
+	io.write(
+		"Usage: lua Generator.lua INPUTFILE OUTPUTFILE\n"..
+		"Converts the Minecraft blocks.json report format to the cuberite "..
+		"block type palette format.\n"..
+		"\n"..
+		"INPUTFILE and OUTPUTFILE must point to a valid path. INPUTFILE must "..
+		"be readable and OUTPUTFILE must be writable. Either can be replaced "..
+		"with `-` (dash character) to point to standard-input or -output.\n");
+	os.exit(message and 1 or 0);
+end
+
+
+-- Test whether the script is run in a path where it can load it's libraries
+if not pcall(function() require("lunajson.decoder") end) then
+	usage("Could not load required libraries, please run `Generator.lua` "..
+		"within its directory and make sure to run `git submodule update`.");
+end
+
+
+-- Check/Prepare CLI arguments
+local inpath, outpath = ...;
+io.input(io.stdin);
+io.output(io.stdout);
+
+if select("#", ...) ~= 2 then
+	usage("Incorrect number of arguments.");
+end
+
+if inpath ~= "-" then
+	local handle, err = io.open(inpath, "r");
+	io.input(handle or usage(err));
+end
+
+if outpath ~= "-" then
+	local handle, err = io.open(outpath, "w");
+	io.output(handle or usage(err));
+end
+
+
+-- Main program starts here
+local decode = (require("lunajson.decoder"))();
+local encode = (require("lunajson.encoder"))();
+
+local input = decode(io.input():read("*a"));
+local registry = {};
+local max_id = -1;
+
+
+for blockname, blockdata in pairs(input) do
+	for i = 1, #(blockdata.states or {}) do
+		local state = blockdata.states[i];
+		assert(registry[state.id + 1] == nil, "Ensure no duplicate IDs");
+
+		-- needed in the end to verify we got no holes in the array:
+		max_id = math.max(max_id, state.id);
+
+		registry[state.id + 1] = {
+			id = assert(state.id, "id is required."),
+			name = assert(blockname, "Block type name is required."),
+			-- default = state.default or nil,  -- may need this later
+			props = state.properties,
+		};
+	end
+end
+
+
+-- The following assertion is not necessary by the current spec, but is required
+-- by how lunajson distinguishes objects from arrays. Also if this fails, it is
+-- _very_ likely that the input file is faulty.
+assert(#registry == max_id + 1, "Ensure that registry has contiguous keys");
+
+local out = {
+	Metadata = {
+		ProtocolBlockTypePaletteVersion = 1
+	},
+	Palette = registry
+};
+
+io.write(encode(out), "\n");