3 files changed, 252 insertions, 0 deletions
diff --git a/codegen/lib/code/packet.py b/codegen/lib/code/packet.py
new file mode 100644
index 00000000..0d3ad138
--- /dev/null
+++ b/codegen/lib/code/packet.py
@@ -0,0 +1,148 @@
+from .utils import burger_type_to_rust_type, write_packet_file
+from ..utils import padded_hex, to_snake_case, to_camel_case
+from ..mappings import Mappings
+
+
+def make_packet_mod_rs_line(packet_id: int, packet_class_name: str):
+    return f'        {padded_hex(packet_id)}: {to_snake_case(packet_class_name)}::{to_camel_case(packet_class_name)},'
+
+
+def generate(burger_packets, mappings: Mappings, target_packet_id, target_packet_direction, target_packet_state):
+    for packet in burger_packets.values():
+        if packet['id'] != target_packet_id:
+            continue
+
+        direction = packet['direction'].lower()  # serverbound or clientbound
+        state = {'PLAY': 'game'}.get(packet['state'], packet['state'].lower())
+
+        if state != target_packet_state or direction != target_packet_direction:
+            continue
+
+        generated_packet_code = []
+        uses = set()
+        generated_packet_code.append(
+            f'#[derive(Clone, Debug, McBuf, {to_camel_case(state)}Packet)]')
+        uses.add(f'packet_macros::{{{to_camel_case(state)}Packet, McBuf}}')
+
+        obfuscated_class_name = packet['class'].split('.')[0].split('$')[0]
+        class_name = mappings.get_class(
+            obfuscated_class_name).split('.')[-1].split('$')[0]
+
+        generated_packet_code.append(
+            f'pub struct {to_camel_case(class_name)} {{')
+
+        for instruction in packet.get('instructions', []):
+            if instruction['operation'] == 'write':
+                obfuscated_field_name = instruction['field']
+                if '.' in obfuscated_field_name or ' ' in obfuscated_field_name or '(' in obfuscated_field_name:
+                    generated_packet_code.append(f'// TODO: {instruction}')
+                    continue
+                field_name = mappings.get_field(
+                    obfuscated_class_name, obfuscated_field_name)
+                if not field_name:
+                    generated_packet_code.append(
+                        f'// TODO: unknown field {instruction}')
+                    continue
+
+                field_type = instruction['type']
+                field_type_rs, is_var, instruction_uses = burger_type_to_rust_type(
+                    field_type)
+                if is_var:
+                    generated_packet_code.append('#[var]')
+                generated_packet_code.append(
+                    f'pub {to_snake_case(field_name)}: {field_type_rs},')
+                uses.update(instruction_uses)
+            else:
+                generated_packet_code.append(f'// TODO: {instruction}')
+                continue
+
+        generated_packet_code.append('}')
+
+        if uses:
+            # empty line before the `use` statements
+            generated_packet_code.insert(0, '')
+        for use in uses:
+            generated_packet_code.insert(0, f'use {use};')
+
+        print(generated_packet_code)
+        write_packet_file(state, to_snake_case(class_name),
+                          '\n'.join(generated_packet_code))
+        print()
+
+        mod_rs_dir = f'../azalea-protocol/src/packets/{state}/mod.rs'
+        with open(mod_rs_dir, 'r') as f:
+            mod_rs = f.read().splitlines()
+
+        pub_mod_line = f'pub mod {to_snake_case(class_name)};'
+        if pub_mod_line not in mod_rs:
+            mod_rs.insert(0, pub_mod_line)
+            packet_mod_rs_line = make_packet_mod_rs_line(
+                packet['id'], class_name)
+
+            in_serverbound = False
+            in_clientbound = False
+            for i, line in enumerate(mod_rs):
+                if line.strip() == 'Serverbound => {':
+                    in_serverbound = True
+                    continue
+                elif line.strip() == 'Clientbound => {':
+                    in_clientbound = True
+                    continue
+                elif line.strip() in ('}', '},'):
+                    if (in_serverbound and direction == 'serverbound') or (in_clientbound and direction == 'clientbound'):
+                        mod_rs.insert(i, packet_mod_rs_line)
+                        break
+                    in_serverbound = in_clientbound = False
+                    continue
+
+                if line.strip() == '' or line.strip().startswith('//') or (not in_serverbound and direction == 'serverbound') or (not in_clientbound and direction == 'clientbound'):
+                    continue
+
+                line_packet_id_hex = line.strip().split(':')[0]
+                assert line_packet_id_hex.startswith('0x')
+                line_packet_id = int(line_packet_id_hex[2:], 16)
+                if line_packet_id > packet['id']:
+                    mod_rs.insert(i, packet_mod_rs_line)
+                    break
+
+            with open(mod_rs_dir, 'w') as f:
+                f.write('\n'.join(mod_rs))
+
+
+def set_packet_ids(packet_ids: list, packet_class_names: list, direction: str, state: str):
+    assert len(packet_ids) == len(packet_class_names)
+
+    mod_rs_dir = f'../azalea-protocol/src/packets/{state}/mod.rs'
+    with open(mod_rs_dir, 'r') as f:
+        mod_rs = f.read().splitlines()
+    new_mod_rs = []
+
+    ignore_lines = False
+
+    for line in mod_rs:
+        if line.strip() == 'Serverbound => {':
+            if direction == 'serverbound':
+                ignore_lines = True
+                for packet_id, packet_class_name in zip(packet_ids, packet_class_names):
+                    new_mod_rs.append(
+                        make_packet_mod_rs_line(packet_id, packet_class_name)
+                    )
+            else:
+                ignore_lines = False
+        elif line.strip() == 'Clientbound => {':
+            if direction == 'serverbound':
+                ignore_lines = True
+                for packet_id, packet_class_name in zip(packet_ids, packet_class_names):
+                    new_mod_rs.append(
+                        make_packet_mod_rs_line(packet_id, packet_class_name)
+                    )
+            else:
+                ignore_lines = False
+        elif line.strip() in ('}', '},'):
+            ignore_lines = False
+
+        if not ignore_lines:
+            new_mod_rs.append(line)
+
+    with open(mod_rs_dir, 'w') as f:
+        f.write('\n'.join(new_mod_rs))
diff --git a/codegen/lib/code/utils.py b/codegen/lib/code/utils.py
new file mode 100644
index 00000000..92d1a9e9
--- /dev/null
+++ b/codegen/lib/code/utils.py
@@ -0,0 +1,73 @@
+
+import os
+
+
+def burger_type_to_rust_type(burger_type):
+    is_var = False
+    uses = set()
+
+    if burger_type == 'byte':
+        field_type_rs = 'i8'
+    elif burger_type == 'short':
+        field_type_rs = 'i16'
+    elif burger_type == 'int':
+        field_type_rs = 'i32'
+    elif burger_type == 'long':
+        field_type_rs = 'i64'
+    elif burger_type == 'float':
+        field_type_rs = 'f32'
+    elif burger_type == 'double':
+        field_type_rs = 'f64'
+
+    elif burger_type == 'varint':
+        is_var = True
+        field_type_rs = 'i32'
+    elif burger_type == 'varlong':
+        is_var = True
+        field_type_rs = 'i64'
+
+    elif burger_type == 'boolean':
+        field_type_rs = 'bool'
+    elif burger_type == 'string':
+        field_type_rs = 'String'
+
+    elif burger_type == 'chatcomponent':
+        field_type_rs = 'Component'
+        uses.add('azalea_chat::component::Component')
+    elif burger_type == 'identifier':
+        field_type_rs = 'ResourceLocation'
+        uses.add('azalea_core::resource_location::ResourceLocation')
+    elif burger_type == 'uuid':
+        field_type_rs = 'Uuid'
+        uses.add('uuid::Uuid')
+    elif burger_type == 'position':
+        field_type_rs = 'BlockPos'
+        uses.add('azalea_core::BlockPos')
+    elif burger_type == 'nbtcompound':
+        field_type_rs = 'azalea_nbt::Tag'
+    elif burger_type == 'itemstack':
+        field_type_rs = 'Slot'
+        uses.add('azalea_core::Slot')
+    elif burger_type == 'metadata':
+        field_type_rs = 'EntityMetadata'
+        uses.add('crate::mc_buf::EntityMetadata')
+    elif burger_type == 'enum':
+        # enums are too complicated, leave those to the user
+        field_type_rs = 'todo!()'
+    elif burger_type.endswith('[]'):
+        field_type_rs, is_var, uses = burger_type_to_rust_type(
+            burger_type[:-2])
+        field_type_rs = f'Vec<{field_type_rs}>'
+    else:
+        print('Unknown field type:', burger_type)
+        exit()
+    return field_type_rs, is_var, uses
+
+
+def write_packet_file(state, packet_name_snake_case, code):
+    with open(f'../azalea-protocol/src/packets/{state}/{packet_name_snake_case}.rs', 'w') as f:
+        f.write(code)
+
+
+def fmt():
+    os.system('cd .. && cargo fmt')
diff --git a/codegen/lib/code/version.py b/codegen/lib/code/version.py
new file mode 100644
index 00000000..b7e5cbcc
--- /dev/null
+++ b/codegen/lib/code/version.py
@@ -0,0 +1,31 @@
+import re
+
+README_DIR = '../README.md'
+VERSION_REGEX = r'\*Currently supported Minecraft version: `(.*)`.\*'
+
+
+def get_version_id() -> str:
+    with open(README_DIR, 'r') as f:
+        readme_text = f.read()
+
+    version_line_match = re.search(VERSION_REGEX, readme_text)
+    if version_line_match:
+        version_id = version_line_match.group(1)
+        return version_id
+    else:
+        raise Exception('Could not find version id in README.md')
+
+
+def set_version_id(version_id: str) -> None:
+    with open(README_DIR, 'r') as f:
+        readme_text = f.read()
+
+    version_line_match = re.search(VERSION_REGEX, readme_text)
+    if version_line_match:
+        readme_text = readme_text.replace(
+            version_line_match.group(1), version_id)
+    else:
+        raise Exception('Could not find version id in README.md')
+
+    with open(README_DIR, 'w') as f:
+        f.write(readme_text)