#!/usr/bin/python3
"""Load settings definitions and generates C++ and Rust code to handle them."""
# 1/ Loads the settings definitions from
# - dnsdist-settings-definitions.yml
# and generates Rust structures and functions that are used to parse the
# YAML settings and populate the Rust structures (via Serde):
# rust/src/lib.rs
# Note that some existing structures and functions present in
# - rust-pre-in.rs
# - rust-middle-in.rs
# - rust-post-in.rs
# are also included into the final rust/src/lib.rs file
# Note that during the compilation of the Rust code to create the static
# dnsdist_rust library, the cxx module also creates corresponding C++ structures
# for interoperability
# 2/ Creates methods to fill DNSdist's internal configuration structures
# from the YAML parameters for all trivial values:
# - dnsdist-configuration-yaml-items-generated.cc
# 3/ Loads the action definitions from:
# - dnsdist-actions-definitions.yml
# - dnsdist-response-actions-definitions.yml
# and generates C++ headers and code to create the wrappers
# for these actions from the Rust structures:
# - dnsdist-rust-bridge-actions-generated.hh
# - dnsdist-rust-bridge-actions-generated-body.hh
# 2/ Loads the selector definitions from:
# - dnsdist-selectors-definitions.yml
# - dnsdist-rust-bridge-selectors-generated.hh
# - dnsdist-rust-bridge-selectors-generated-body.hh
# and generates C++ headers and code to create the wrappers
# for these selectors from the Rust structures:
# The format of the definitions, in YAML, is a simple list of items.
# Each item has a name and an optional list of parameters.
# Parameters have a name, a type, and optionally a default value
# Types are the Rust ones, converted to the C++ equivalent when needed
# Default values are written as quoted strings, with the exception of the
# special unquoted true value which means to use the default value for the
# object type, which needs to exist.
# Items can optionally have the following properties:
# - 'skip-cpp' is not used by this script but is used by the dnsdist-rules-generator.py one, where it means that the corresponding C++ factory and Lua bindinds will not be generated, which is useful for objects taking parameters that cannot be directly mapped
# - 'skip-rust' means that the C++ code to create the Rust-side version of an action or selector will not generated
# - 'skip-serde' means that the Rust structure representing that action or selector in the YAML setting will not be directly created by Serde. It is used for selectors that reference another selector themselves, or actions referencing another action.
# - 'lua-name' name of the Lua directive for this setting
# - 'internal-field-name' name of the corresponding field in DNSdist's internal configuration structures, which is used to generate 'dnsdist-configuration-yaml-items-generated.cc'
# - 'runtime-configurable' whether this setting can be set at runtime or can only be set at configuration time

import os
import re
import sys
import tempfile
import yaml

def quote(arg):
    """Return a quoted string"""
    return '"' + arg + '"'

def get_vector_sub_type(rust_type):
    return rust_type[4:-1]

def is_vector_of(rust_type):
    return rust_type.startswith('Vec<')

def is_type_native(rust_type):
    if is_vector_of(rust_type):
        sub_type = get_vector_sub_type(rust_type)
        return is_type_native(sub_type)
    return rust_type in ['bool', 'u8', 'u16', 'u32', 'u64', 'f64', 'String']

def is_value_rust_default(rust_type, value):
    """Is a value the same as its corresponding Rust default?"""
    if rust_type == 'bool':
        return value == 'false'
    if rust_type  in ('u8', 'u16', 'u32', 'u64'):
        return value in (0, '0', '')
    if rust_type == 'f64':
        return value in ('0.0', 0.0)
    if rust_type == 'String':
        return value == ''
    if rust_type == 'Vec<String>':
        return value == '' or value == '[]'
    if is_vector_of(rust_type):
        return value == '[]'
    return False

def get_rust_field_name(name):
    return name.replace('-', '_').lower()

def get_rust_object_name(name):
    object_name = ''
    capitalize = True
    for char in name:
        if char in ['-', '_']:
            capitalize = True
            continue
        if capitalize:
            char = char.upper()
            capitalize = False
        object_name += char

    return object_name

def gen_rust_vec_default_functions(name, type_name, def_value):
    """Generate Rust code for the default handling of a vector for type_name"""
    ret = f'// DEFAULT HANDLING for {name}\n'
    ret += f'fn default_value_{name}() -> Vec<dnsdistsettings::{type_name}> {{\n'
    ret += f'    let msg = "default value defined for `{name}\' should be valid YAML";'
    ret += f'    let deserialized: Vec<dnsdistsettings::{type_name}> = serde_yaml::from_str({quote(def_value)}).expect(&msg);\n'
    ret += '    deserialized\n'
    ret += '}\n'
    ret += f'fn default_value_equal_{name}(value: &Vec<dnsdistsettings::{type_name}>)'
    ret += '-> bool {\n'
    ret += f'    let def = default_value_{name}();\n'
    ret += '    &def == value\n'
    ret += '}\n\n'
    return ret

# Example snippet generated
# fn default_value_general_query_local_address() -> Vec<String> {
#    vec![String::from("0.0.0.0"), ]
#}
#fn default_value_equal_general_query_local_address(value: &Vec<String>) -> bool {
#    let def = default_value_general_query_local_address();
#    &def == value
#}
def gen_rust_stringvec_default_functions(default, name):
    """Generate Rust code for the default handling of a vector for Strings"""
    ret = f'// DEFAULT HANDLING for {name}\n'
    ret += f'fn default_value_{name}() -> Vec<String> {{\n'
    parts = re.split('[ \t,]+', default)
    if len(parts) > 0:
        ret += '    vec![\n'
        for part in parts:
            if part == '':
                continue
            ret += f'        String::from({quote(part)}),\n'
        ret += '    ]\n'
    else:
        ret  += '    vec![]\n'
    ret += '}\n'
    ret += f'fn default_value_equal_{name}(value: &Vec<String>) -> bool {{\n'
    ret += f'    let def = default_value_{name}();\n'
    ret += '    &def == value\n'
    ret += '}\n\n'
    return ret

def gen_rust_default_functions(rust_type, default, name):
    """Generate Rust code for the default handling"""
    if rust_type in ['Vec<String>']:
        return gen_rust_stringvec_default_functions(default, name)
    ret = f'// DEFAULT HANDLING for {name}\n'
    ret += f'fn default_value_{name}() -> {rust_type} {{\n'
    rustdef = quote(default)
    ret += f"    String::from({rustdef})\n"
    ret += '}\n'
    if rust_type == 'String':
        rust_type = 'str'
    ret += f'fn default_value_equal_{name}(value: &{rust_type})'
    ret += '-> bool {\n'
    ret += f'    value == default_value_{name}()\n'
    ret += '}\n\n'
    return ret

def write_rust_default_trait_impl(struct, skip_namespace=False):
    """Generate Rust code for the default Trait for a structure"""
    namespace = 'dnsdistsettings::' if not skip_namespace else ''
    result = ''
    result += f'impl Default for {namespace}{struct} {{\n'
    result += '    fn default() -> Self {\n'
    result += f'        let deserialized: {namespace}{struct} = serde_yaml::from_str("").unwrap();\n'
    result += '        deserialized\n'
    result += '    }\n'
    result += '}\n\n'
    return result

def get_rust_serde_annotations(rust_type, default, rename, obj, field, default_functions):
    rename_value = f'rename = "{rename}", ' if rename else ''
    if default is None:
        if not rename_value:
            return ''
        return f'#[serde({rename_value})]'
    if default is True or is_value_rust_default(rust_type, default):
        return f'#[serde({rename_value}default, skip_serializing_if = "crate::is_default")]'
    type_upper = rust_type.capitalize()
    if rust_type == 'bool':
        return f'''#[serde({rename_value}default = "crate::{type_upper}::<{default}>::value", skip_serializing_if = "crate::if_true")]'''
    if rust_type in ['String', 'Vec<String>']:
        basename = obj + '_' + field
        default_functions.append(gen_rust_default_functions(rust_type, default, basename))
        return f'''#[serde({rename_value}default = "crate::default_value_{basename}", skip_serializing_if = "crate::default_value_equal_{basename}")]'''
    return f'''#[serde({rename_value}default = "crate::{type_upper}::<{default}>::value", skip_serializing_if = "crate::{type_upper}::<{default}>::is_equal")]'''

def get_converted_serde_type(rust_type):
    if is_type_native(rust_type):
        return rust_type

    if is_vector_of(rust_type):
        sub_type = get_vector_sub_type(rust_type)
        if sub_type in ['Action', 'Selector']:
            return rust_type
        if sub_type in ['QueryRuleConfiguration', 'ResponseRuleConfiguration']:
            return f'Vec<{sub_type}Serde>'
        return f'Vec<dnsdistsettings::{sub_type}>'

    return f'dnsdistsettings::{rust_type}'

def get_rust_struct_fields_from_definition(name, keys, default_functions, indent_spaces, special_serde_object=False):
    if not 'parameters' in keys:
        return ''
    output = ''
    indent = ' '*indent_spaces
    for parameter in keys['parameters']:
        parameter_name = get_rust_field_name(parameter['name']) if not 'rename' in parameter else parameter['rename']
        rust_type = parameter['type']
        if 'rust-type' in parameter:
            rust_type = parameter['rust-type']
        if special_serde_object:
            rust_type = get_converted_serde_type(rust_type)
        else:
            # cxx does not support Enums, so we have to convert them to opaque types
            if rust_type == 'Action':
                rust_type = 'SharedDNSAction'
            elif rust_type == 'ResponseAction':
                rust_type = 'SharedDNSResponseAction'
            elif rust_type == 'Selector':
                rust_type = 'SharedDNSSelector'
            elif rust_type == 'Vec<Selector>':
                rust_type = 'Vec<SharedDNSSelector>'
        rename = parameter['name'] if parameter_name != parameter['name'] else None
        if special_serde_object or not 'skip-serde' in keys or not keys['skip-serde']:
            default_str = get_rust_serde_annotations(rust_type, parameter['default'] if 'default' in parameter else None, rename, get_rust_field_name(name), parameter_name, default_functions)
            if default_str:
                output += indent + default_str + '\n'
        output += f'{indent}{parameter_name}: {rust_type},\n'

    return output

def get_rust_struct_from_definition(name, keys, default_functions, indent_spaces=4, special_serde_object=False):
    if not 'parameters' in keys:
        return ''
    obj_name = get_rust_object_name(name)
    indent = ' '*indent_spaces
    output = ''
    if special_serde_object or not 'skip-serde' in keys or not keys['skip-serde']:
        output += f'''{indent}#[derive(Deserialize, Serialize, Debug, PartialEq)]
{indent}#[serde(deny_unknown_fields)]
'''
    elif name == 'global':
        output += f'{indent}#[derive(Default)]\n'

    name_suffix = 'Serde' if name == 'global' and special_serde_object else ''
    output += f'''{indent}struct {obj_name}Configuration{name_suffix} {{
'''
    indent_spaces += 4
    indent = ' '*indent_spaces
    output += get_rust_struct_fields_from_definition(name, keys, default_functions, indent_spaces, special_serde_object=special_serde_object)
    output += '    }\n'
    if special_serde_object or not 'skip-serde' in keys or not keys['skip-serde']:
        default_functions.append(write_rust_default_trait_impl(f'{obj_name}Configuration{name_suffix}', special_serde_object))
    return output

def should_validate_type(rust_type):
    if is_vector_of(rust_type):
        sub_type = get_vector_sub_type(rust_type)
        return should_validate_type(sub_type)
    if rust_type in ['bool', 'u8', 'u16', 'u32', 'u64', 'f64', 'String']:
        return False
    if rust_type in ['Action', 'Selector', 'dnsdistsettings::SelectorsConfiguration']:
        return False
    return True

def get_validation_for_field(field_name, rust_type):
    if not should_validate_type(rust_type):
        return ''
    if not is_vector_of(rust_type):
        return f'        self.{field_name}.validate()?;\n'

    return f'''        for sub_type in &self.{field_name} {{
        sub_type.validate()?;
    }}
'''

def get_struct_validation_function_from_definition(name, parameters, special_serde_object=False):
    if len(parameters) == 0:
        return ''
    namespace = 'dnsdistsettings::' if not special_serde_object else ''
    suffix = 'Serde' if special_serde_object else ''
    struct_name = get_rust_object_name(name)
    output = f'''impl {namespace}{struct_name}Configuration{suffix} {{
    fn validate(&self) -> Result<(), ValidationError> {{
'''
    for parameter in parameters:
        field_name = get_rust_field_name(parameter['name']) if parameter['name'] != 'namespace' else 'name_space'
        rust_type = parameter['type']
        output += get_validation_for_field(field_name, rust_type)
    output += '''        Ok(())
    }
}'''
    return output

def get_definitions_from_file(def_file):
    with open(def_file, 'rt', encoding="utf-8") as fd:
        definitions = yaml.safe_load(fd.read())
        return definitions

def include_file(out_fp, include_file_name):
    with open(include_file_name, mode='r', encoding='utf-8') as in_fp:
        basename = os.path.basename(include_file_name)
        out_fp.write(f'// START INCLUDE {basename}\n')
        out_fp.write(in_fp.read())
        out_fp.write(f'// END INCLUDE {basename}\n')

def generate_flat_settings_for_cxx(definitions, src_dir, out_file_path):
    cxx_flat_settings_fp = get_temporary_file_for_generated_code(out_file_path)

    include_file(cxx_flat_settings_fp, src_dir + '/dnsdist-configuration-yaml-items-pre-in.cc')

    # first we do runtime-settable settings
    cxx_flat_settings_fp.write('''#if defined(HAVE_YAML_CONFIGURATION)
#include "rust/cxx.h"
#include "rust/lib.rs.h"
#include "dnsdist-configuration-yaml-internal.hh"

namespace dnsdist::configuration::yaml
{
void convertRuntimeFlatSettingsFromRust(const dnsdist::rust::settings::GlobalConfiguration& yamlConfig, dnsdist::configuration::RuntimeConfiguration& config)
{\n''')
    for category_name, keys in definitions.items():
        if not 'parameters' in keys:
            continue

        if 'category' in keys:
            category_name = keys['category']
        else:
            category_name = get_rust_field_name(category_name)

        for parameter in keys['parameters']:
            if not 'internal-field-name' in parameter or not 'runtime-configurable' in parameter or not parameter['runtime-configurable']:
                continue
            internal_field_name = parameter['internal-field-name']
            rust_field_name = get_rust_field_name(parameter['name']) if not 'rename' in parameter else parameter['rename']
            default = parameter['default'] if parameter['type'] != 'String' else '"' + parameter['default'] + '"'
            cxx_flat_settings_fp.write(f'  if (config.{internal_field_name} == {default}) {{\n')
            if parameter['type'] != 'String':
                cxx_flat_settings_fp.write(f'    config.{internal_field_name} = yamlConfig.{category_name}.{rust_field_name};\n')
            else:
                cxx_flat_settings_fp.write(f'    config.{internal_field_name} = std::string(yamlConfig.{category_name}.{rust_field_name});\n')
            cxx_flat_settings_fp.write('  }\n')

    cxx_flat_settings_fp.write('''}\n''')

    # then immutable ones
    cxx_flat_settings_fp.write('''void convertImmutableFlatSettingsFromRust(const dnsdist::rust::settings::GlobalConfiguration& yamlConfig, dnsdist::configuration::ImmutableConfiguration& config)
{\n''')
    for category_name, keys in definitions.items():
        if not 'parameters' in keys:
            continue

        if 'category' in keys:
            category_name = keys['category']
        else:
            category_name = get_rust_field_name(category_name)

        for parameter in keys['parameters']:
            if not 'internal-field-name' in parameter or not 'runtime-configurable' in parameter or parameter['runtime-configurable']:
                continue
            internal_field_name = parameter['internal-field-name']
            rust_field_name = get_rust_field_name(parameter['name']) if not 'rename' in parameter else parameter['rename']
            default = parameter['default'] if parameter['type'] != 'String' else '"' + parameter['default'] + '"'
            cxx_flat_settings_fp.write(f'  if (config.{internal_field_name} == {default}) {{\n')
            if parameter['type'] != 'String':
                cxx_flat_settings_fp.write(f'    config.{internal_field_name} = yamlConfig.{category_name}.{rust_field_name};\n')
            else:
                cxx_flat_settings_fp.write(f'    config.{internal_field_name} = std::string(yamlConfig.{category_name}.{rust_field_name});\n')
            cxx_flat_settings_fp.write('  }\n')

    cxx_flat_settings_fp.write('''}\n
}
#endif /* defined(HAVE_YAML_CONFIGURATION) */
''')

    os.rename(cxx_flat_settings_fp.name, out_file_path + '/dnsdist-configuration-yaml-items-generated.cc')

def generate_actions_config(output, def_dir, response, default_functions):
    suffix = 'ResponseAction' if response else 'Action'
    actions_definitions = get_actions_definitions(def_dir, response)
    action_buffer = ''
    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        struct_name = f'{name}{suffix}Configuration'
        indent = ' ' * 4
        if not 'skip-serde' in action or not action['skip-serde']:
            action_buffer += f'''{indent}#[derive(Deserialize, Serialize, Debug, PartialEq)]
{indent}#[serde(deny_unknown_fields)]\n'''
        else:
            action_buffer += f'{indent}#[derive(Default)]\n'

        action_buffer += f'{indent}struct {struct_name} {{\n'

        indent = ' ' * 8
        if not 'skip-serde' in action or not action['skip-serde']:
            action_buffer += f'{indent}#[serde(default, skip_serializing_if = "crate::is_default")]\n'
        action_buffer += f'{indent}name: String,\n'

        action_buffer += get_rust_struct_fields_from_definition(struct_name, action, default_functions, 8)

        action_buffer += '    }\n\n'

    output.write(action_buffer)

def generate_selectors_config(output, def_dir, default_functions):
    suffix = 'Selector'
    selectors_definitions = get_selectors_definitions(def_dir)
    selector_buffer = ''
    for selector in selectors_definitions:
        name = get_rust_object_name(selector['name'])
        struct_name = f'{name}{suffix}Configuration'
        indent = ' ' * 4
        if not 'skip-serde' in selector or not selector['skip-serde']:
            selector_buffer += f'''{indent}#[derive(Deserialize, Serialize, Debug, PartialEq)]
{indent}#[serde(deny_unknown_fields)]\n'''
        else:
            selector_buffer += f'{indent}#[derive(Default)]\n'

        selector_buffer += f'{indent}struct {struct_name} {{\n'

        indent = ' ' * 8
        if not 'skip-serde' in selector or not selector['skip-serde']:
            selector_buffer += f'{indent}#[serde(default, skip_serializing_if = "crate::is_default")]\n'
        selector_buffer += f'{indent}name: String,\n'

        selector_buffer += get_rust_struct_fields_from_definition(struct_name, selector, default_functions, 8)

        selector_buffer += '    }\n\n'

    output.write(selector_buffer)

def generate_cpp_action_headers(def_dir, cxx_dest_dir):
    cpp_action_headers_fp = get_temporary_file_for_generated_code(cxx_dest_dir)
    header_buffer = ''

    # query actions
    actions_definitions = get_actions_definitions(def_dir, False)
    suffix = 'Action'
    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        struct_name = f'{name}{suffix}Configuration'
        header_buffer += f'struct {struct_name};\n'
        header_buffer += f'std::shared_ptr<DNS{suffix}Wrapper> get{name}{suffix}(const {struct_name}& config);\n'

    # response actions
    actions_definitions = get_actions_definitions(def_dir, True)
    suffix = 'ResponseAction'
    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        struct_name = f'{name}{suffix}Configuration'
        header_buffer += f'struct {struct_name};\n'
        header_buffer += f'std::shared_ptr<DNS{suffix}Wrapper> get{name}{suffix}(const {struct_name}& config);\n'

    cpp_action_headers_fp.write(header_buffer)
    os.rename(cpp_action_headers_fp.name, f'{cxx_dest_dir}/dnsdist-rust-bridge-actions-generated.hh')

def generate_cpp_selector_headers(def_dir, cxx_dest_dir):
    cpp_selector_headers_fp = get_temporary_file_for_generated_code(cxx_dest_dir)
    header_buffer = ''

    selectors_definitions = get_selectors_definitions(def_dir)
    suffix = 'Selector'
    for selector in selectors_definitions:
        name = get_rust_object_name(selector['name'])
        struct_name = f'{name}{suffix}Configuration'
        header_buffer += f'struct {struct_name};\n'
        header_buffer += f'std::shared_ptr<DNS{suffix}> get{name}{suffix}(const {struct_name}& config);\n'
    cpp_selector_headers_fp.write(header_buffer)
    os.rename(cpp_selector_headers_fp.name, f'{cxx_dest_dir}/dnsdist-rust-bridge-selectors-generated.hh')

def get_cpp_parameters(struct_name, parameters, skip_name):
    output = ''
    for parameter in parameters:
        name = parameter['name']
        ptype = parameter['type']
        if name == 'name' and skip_name:
            continue
        pname = get_rust_field_name(name)
        if len(output) > 0:
            output += ', '
        field = f'{struct_name}.{pname}'
        if ptype == 'PacketBuffer':
            field = f'PacketBuffer({field}.data(), {field}.data() + {field}.size())'
        elif ptype == 'DNSName':
            field = f'DNSName(std::string({field}))'
        elif ptype == 'ComboAddress':
            field = f'ComboAddress(std::string({field}))'
        elif ptype == 'String':
            field = f'std::string({field})'
        elif ptype == 'ResponseConfig':
            field = f'convertResponseConfig({field})'
        elif ptype == 'Vec<SVCRecordParameters>':
            field = f'convertSVCRecordParameters({field})'
        elif ptype == 'SOAParams':
            field = f'convertSOAParams({field})'
        elif ptype == 'RCode':
            field = f'dnsdist::configuration::yaml::strToRCode("{struct_name}", "{name}", {field})'
        elif ptype == 'Opcode':
            field = f'dnsdist::configuration::yaml::strToOpcode("{struct_name}", "{name}", {field})'
        output += field
    return output

def generate_cpp_action_wrappers(def_dir, cxx_dest_dir):
    cpp_action_wrappers_fp = get_temporary_file_for_generated_code(cxx_dest_dir)
    wrappers_buffer = ''

    # query actions
    actions_definitions = get_actions_definitions(def_dir, False)
    suffix = 'Action'
    for action in actions_definitions:
        if 'skip-rust' in action and action['skip-rust']:
            continue
        name = get_rust_object_name(action['name'])
        struct_name = f'{name}{suffix}Configuration'
        parameters = get_cpp_parameters('config', action['parameters'], True) if 'parameters' in action else ''
        wrappers_buffer += f'''std::shared_ptr<DNS{suffix}Wrapper> get{name}{suffix}(const {struct_name}& config)
{{
  auto action = dnsdist::actions::get{name}{suffix}({parameters});
  return newDNSActionWrapper(std::move(action), config.name);
}}
'''

    # response actions
    actions_definitions = get_actions_definitions(def_dir, True)
    suffix = 'ResponseAction'
    for action in actions_definitions:
        if 'skip-rust' in action and action['skip-rust']:
            continue
        name = get_rust_object_name(action['name'])
        struct_name = f'{name}{suffix}Configuration'
        parameters = get_cpp_parameters('config', action['parameters'], True) if 'parameters' in action else ''
        wrappers_buffer += f'''std::shared_ptr<DNS{suffix}Wrapper> get{name}{suffix}(const {struct_name}& config)
{{
  auto action = dnsdist::actions::get{name}{suffix}({parameters});
  return newDNSResponseActionWrapper(std::move(action), config.name);
}}
'''

    cpp_action_wrappers_fp.write(wrappers_buffer)
    os.rename(cpp_action_wrappers_fp.name, f'{cxx_dest_dir}/dnsdist-rust-bridge-actions-generated-body.hh')

def generate_cpp_selector_wrappers(def_dir, cxx_dest_dir):
    cpp_selector_wrappers_fp = get_temporary_file_for_generated_code(cxx_dest_dir)
    wrappers_buffer = ''

    selectors_definitions = get_selectors_definitions(def_dir)
    suffix = 'Selector'
    for selector in selectors_definitions:
        if 'skip-rust' in selector and selector['skip-rust']:
            continue
        name = get_rust_object_name(selector['name'])
        struct_name = f'{name}{suffix}Configuration'
        parameters = get_cpp_parameters('config', selector['parameters'], True) if 'parameters' in selector else ''
        wrappers_buffer += f'''std::shared_ptr<DNS{suffix}> get{name}{suffix}(const {struct_name}& config)
{{
  auto selector = dnsdist::selectors::get{name}{suffix}({parameters});
  return newDNSSelector(std::move(selector), config.name);
}}
'''

    cpp_selector_wrappers_fp.write(wrappers_buffer)
    os.rename(cpp_selector_wrappers_fp.name, f'{cxx_dest_dir}/dnsdist-rust-bridge-selectors-generated-body.hh')

def generate_rust_actions_enum(output, def_dir, response):
    suffix = 'ResponseAction' if response else 'Action'
    actions_definitions = get_actions_definitions(def_dir, response)
    enum_buffer = f'''#[derive(Default, Serialize, Deserialize, Debug, PartialEq)]
#[serde(tag = "type")]
enum {suffix} {{
    #[default]
    Default,
'''

    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        struct_name = f'{name}{suffix}Configuration'
        if struct_name in ['ContinueActionConfiguration']:
            # special version for Serde
            enum_buffer += f'    {name}({struct_name}Serde),\n'
        else:
            enum_buffer += f'    {name}(dnsdistsettings::{struct_name}),\n'

    enum_buffer += '}\n\n'

    output.write(enum_buffer)

def generate_rust_selectors_enum(output, def_dir):
    suffix = 'Selector'
    selectors_definitions = get_selectors_definitions(def_dir)
    enum_buffer = f'''#[derive(Default, Serialize, Deserialize, Debug, PartialEq)]
#[serde(tag = "type")]
enum {suffix} {{
    #[default]
    Default,
'''

    for selector in selectors_definitions:
        name = get_rust_object_name(selector['name'])
        struct_name = f'{name}{suffix}Configuration'
        if struct_name in ['AndSelectorConfiguration', 'OrSelectorConfiguration', 'NotSelectorConfiguration']:
            # special version for Serde
            enum_buffer += f'    {name}({struct_name}Serde),\n'
        else:
            enum_buffer += f'    {name}(dnsdistsettings::{struct_name}),\n'

    enum_buffer += '}\n\n'

    output.write(enum_buffer)

def get_actions_definitions(def_dir, response):
    def_file = f'{def_dir}/dnsdist-response-actions-definitions.yml' if response else f'{def_dir}/dnsdist-actions-definitions.yml'
    return get_definitions_from_file(def_file)

def get_selectors_definitions(def_dir):
    def_file = f'{def_dir}/dnsdist-selectors-definitions.yml'
    return get_definitions_from_file(def_file)

def generate_cpp_action_selector_functions_callable_from_rust(output, def_dir):
    output_buffer = '''
    /*
     * Functions callable from Rust (actions and selectors)
     */
    unsafe extern "C++" {
'''
    # first query actions
    actions_definitions = get_actions_definitions(def_dir, False)
    suffix = 'Action'
    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        output_buffer += f'        fn get{name}{suffix}(config: &{name}{suffix}Configuration) -> Result<SharedPtr<DNS{suffix}Wrapper>>;\n'

    # then response actions
    actions_definitions = get_actions_definitions(def_dir, True)
    suffix = 'ResponseAction'
    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        output_buffer += f'        fn get{name}{suffix}(config: &{name}{suffix}Configuration) -> Result<SharedPtr<DNS{suffix}Wrapper>>;\n'

    # then selectors
    selectors_definitions = get_selectors_definitions(def_dir)
    suffix = 'Selector'
    for selector in selectors_definitions:
        name = get_rust_object_name(selector['name'])
        output_buffer += f'        fn get{name}{suffix}(config: &{name}{suffix}Configuration) -> Result<SharedPtr<DNS{suffix}>>;\n'

    output_buffer += '    }\n'
    output.write(output_buffer)

def generate_rust_action_to_config(output, def_dir, response):
    suffix = 'ResponseAction' if response else 'Action'
    actions_definitions = get_actions_definitions(def_dir, response)
    function_name = 'get_one_action_from_serde' if not response else 'get_one_response_action_from_serde'
    enum_buffer = f'''fn {function_name}(action: &{suffix}) -> Result<dnsdistsettings::SharedDNS{suffix}, cxx::Exception> {{
    match action {{
        {suffix}::Default => {{}}
'''

    for action in actions_definitions:
        name = get_rust_object_name(action['name'])
        if name in ['Continue']:
            enum_buffer += f'''        {suffix}::{name}(cont) => {{
             let mut config: dnsdistsettings::{name}{suffix}Configuration = Default::default();
             config.action = get_one_action_from_serde(&*cont.action)?;
             return Ok(dnsdistsettings::SharedDNS{suffix} {{
                 action: dnsdistsettings::get{name}{suffix}(&config)?,
             }});
        }}
'''
        else:
            enum_buffer += f'''        {suffix}::{name}(config) => {{
                return Ok(dnsdistsettings::SharedDNS{suffix} {{
                    action: dnsdistsettings::get{name}{suffix}(&config)?,
                }});
            }}
'''

    enum_buffer += '''    }
    panic!("no action")
}
'''

    output.write(enum_buffer)

def generate_rust_selector_to_config(output, def_dir):
    suffix = 'Selector'
    selectors_definitions = get_selectors_definitions(def_dir)
    function_name = 'get_one_selector_from_serde'
    enum_buffer = f'''fn {function_name}(selector: &{suffix}) -> Result<dnsdistsettings::SharedDNS{suffix}, cxx::Exception> {{
    match selector {{
        {suffix}::Default => {{}}
'''

    for selector in selectors_definitions:
        name = get_rust_object_name(selector['name'])
        var = name.lower()
        if name in ['And', 'Or']:
            enum_buffer += f'''        {suffix}::{name}({var}) => {{
             let mut config: dnsdistsettings::{name}{suffix}Configuration = Default::default();
             for sub_selector in &{var}.selectors {{
                 config.selectors.push(get_one_selector_from_serde(&sub_selector)?)
             }}
             return Ok(dnsdistsettings::SharedDNS{suffix} {{
                       selector: dnsdistsettings::get{name}{suffix}(&config)?
             }})
        }}
'''
        elif name in ['Not']:
            enum_buffer += f'''        {suffix}::{name}({var}) => {{
             let mut config: dnsdistsettings::{name}{suffix}Configuration = Default::default();
             match get_one_selector_from_serde(&*{var}.selector) {{
                 Ok(sel) => config.selector = sel,
                 Err(e) => return Err(e),
             }}
             match dnsdistsettings::get{name}{suffix}(&config) {{
                 Ok(sel) => return Ok(dnsdistsettings::SharedDNS{suffix} {{
                                   selector: sel,
                            }}),
                 Err(e) => return Err(e),
             }}
        }}
'''
        else:
            enum_buffer += f'''        {suffix}::{name}({var}) => {{
            match dnsdistsettings::get{name}{suffix}(&{var}) {{
                Ok(sel) => return Ok(dnsdistsettings::SharedDNS{suffix} {{
                                  selector: sel,
                           }}),
                Err(e) => return Err(e),
            }}
        }}
'''

    enum_buffer += '''    }
    panic!("No selector")
}
'''

    output.write(enum_buffer)

def handle_structures(generated_fp, definitions, default_functions, validation_functions):
    for definition_name, keys in definitions.items():
        generated_fp.write(get_rust_struct_from_definition(definition_name, keys, default_functions) + '\n')
        if definition_name not in ['global', 'proto_buf_meta', 'proxy_protocol_value', 'query_rule', 'response_rule']:
            validation_functions.append(get_struct_validation_function_from_definition(definition_name, keys['parameters'] if 'parameters' in keys else []))

def get_temporary_file_for_generated_code(directory):
    generated_fp = tempfile.NamedTemporaryFile(mode='w+t', encoding='utf-8', dir=directory, delete=False)
    generated_fp.write('// !! This file has been generated by dnsdist-settings-generator.py, do not edit by hand!!\n')
    return generated_fp

def main():
    if len(sys.argv) != 4:
        print(f'Usage: {sys.argv[0]} <path/to/definitions/files> <rust/output/dir> <cxx/build/root/dir>')
        sys.exit(1)

    definitions_dir = sys.argv[1]
    rust_dir = sys.argv[2]
    cxx_build_dir = sys.argv[3]
    definitions = get_definitions_from_file(definitions_dir + '/dnsdist-settings-definitions.yml')
    default_functions = []
    validation_functions = []

    generate_cpp_action_headers(definitions_dir, cxx_build_dir)
    generate_cpp_action_wrappers(definitions_dir, cxx_build_dir)
    generate_cpp_selector_headers(definitions_dir, cxx_build_dir)
    generate_cpp_selector_wrappers(definitions_dir, cxx_build_dir)

    generated_fp = get_temporary_file_for_generated_code(f'{rust_dir}/rust/src/')
    include_file(generated_fp, f'{rust_dir}/rust-pre-in.rs')

    generate_actions_config(generated_fp, definitions_dir, False, default_functions)
    generate_actions_config(generated_fp, definitions_dir, True, default_functions)
    generate_selectors_config(generated_fp, definitions_dir, default_functions)

    handle_structures(generated_fp, definitions, default_functions, validation_functions)

    generate_cpp_action_selector_functions_callable_from_rust(generated_fp, definitions_dir)

    include_file(generated_fp, f'{rust_dir}/rust-middle-in.rs')
    # we are now outside of the dnsdistsettings namespace

    # generate the special global configuration Serde structure
    for definition_name, keys in definitions.items():
        if definition_name == 'global':
            generated_fp.write(get_rust_struct_from_definition(definition_name, keys, default_functions, special_serde_object=True) + '\n')
            validation_functions.append(get_struct_validation_function_from_definition(definition_name, keys['parameters'] if 'parameters' in keys else [], True))

    generate_rust_actions_enum(generated_fp, definitions_dir, False)
    generate_rust_actions_enum(generated_fp, definitions_dir, True)
    generate_rust_selectors_enum(generated_fp, definitions_dir)

    # the generated functions for the default values and validation
    for function_def in default_functions:
        generated_fp.write(function_def + '\n')

    for function_def in validation_functions:
        generated_fp.write(function_def + '\n')

    generate_rust_action_to_config(generated_fp, definitions_dir, False)
    generate_rust_action_to_config(generated_fp, definitions_dir, True)
    generate_rust_selector_to_config(generated_fp, definitions_dir)

    include_file(generated_fp, rust_dir + '/rust-post-in.rs')

    os.rename(generated_fp.name, rust_dir + '/rust/src/lib.rs')

    generate_flat_settings_for_cxx(definitions, rust_dir, f'{cxx_build_dir}')

if __name__ == '__main__':
    main()
