#include "../../backend.h"

#include "../../interface.h"
#include "../../msg.h"
#include "../../type.h"

#include <blue/core/hash.h>
#include <blue/io/file.h>
#include <blue/io/path.h>
#include <stdarg.h>
#include <stddef.h>

struct emit_ctx {
	b_stream *ctx_out;
	size_t ctx_max_handle_params;
};

static void emit(struct emit_ctx *ctx, const char *format, ...)
{
	va_list arg;
	va_start(arg, format);
	b_stream_write_vfmt(ctx->ctx_out, NULL, format, arg);
	va_end(arg);
}

static void emit_indent(struct emit_ctx *ctx)
{
	b_stream_push_indent(ctx->ctx_out, 4);
}

static void emit_indent_zero(struct emit_ctx *ctx)
{
	b_stream_push_indent(ctx->ctx_out, -100);
}

static void emit_unindent(struct emit_ctx *ctx)
{
	b_stream_pop_indent(ctx->ctx_out);
}

static int emit_include(struct emit_ctx *ctx, const char *path, bool system)
{
	if (system) {
		emit(ctx, "#include <%s>\n", path);
	} else {
		emit(ctx, "#include \"%s\"\n", path);
	}

	return 0;
}

static int emit_header_guard_start(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	b_string *header_guard = b_string_create();
	b_string_append_cstrf(header_guard, "%s_H_", iface->if_name);
	b_string_toupper(header_guard);

	emit(ctx,
	     "#ifndef %s\n#define %s\n\n",
	     b_string_ptr(header_guard),
	     b_string_ptr(header_guard));
	b_string_unref(header_guard);
	return 0;
}

static int emit_header_guard_end(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	emit(ctx, "\n#endif");
	return 0;
}

static size_t get_msg_handle_params(const struct msg_definition *msg)
{
	size_t count = 0;
	b_queue_entry *entry = b_queue_first(&msg->msg_params);
	while (entry) {
		const struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		if (param->p_type->ty_id == TYPE_HANDLE) {
			count++;
		}

		entry = b_queue_next(entry);
	}

	return count;
}

static size_t get_max_handle_params(const struct interface_definition *iface)
{
	size_t count = 0;
	b_queue_entry *entry = b_queue_first(&iface->if_msg);
	while (entry) {
		const struct msg_definition *msg
			= b_unbox(struct msg_definition, entry, msg_entry);
		size_t msg_count = get_msg_handle_params(msg);

		if (msg_count > count) {
			count = msg_count;
		}

		entry = b_queue_next(entry);
	}

	return count;
}

static int emit_interface_id_macros(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	b_string *iface_define_name = b_string_create();
	b_string_append_cstr(iface_define_name, iface->if_name);
	b_string_toupper(iface_define_name);

	uint32_t protocol_id = iface->if_id;

	emit(ctx,
	     "/* %s protocol ID */\n#define INTERFACE_%s 0x%08xU\n\n",
	     iface->if_name,
	     b_string_ptr(iface_define_name),
	     protocol_id);
	b_string_unref(iface_define_name);

	b_string *msg_name = b_string_create();
	b_queue_entry *entry = b_queue_first(&iface->if_msg);
	while (entry) {
		const struct msg_definition *msg
			= b_unbox(struct msg_definition, entry, msg_entry);
		b_string_clear(msg_name);
		b_string_append_cstrf(
			msg_name,
			"%s.%s",
			iface->if_name,
			msg->msg_name);

		emit(ctx, "/* %s message ID */\n", b_string_ptr(msg_name));
		uint16_t msg_id = msg->msg_id;

		b_string_clear(msg_name);
		b_string_append_cstrf(
			msg_name,
			"%s_%s",
			iface->if_name,
			msg->msg_name);
		b_string_toupper(msg_name);
		emit(ctx,
		     "#define MSG_%s 0x%04xU\n",
		     b_string_ptr(msg_name),
		     msg_id);

		entry = b_queue_next(entry);
	}

	emit(ctx, "\n");
	b_string_unref(msg_name);

	return 0;
}

static int emit_msg_struct_member(
	struct emit_ctx *ctx,
	const struct msg_parameter *param)
{
	switch (param->p_type->ty_id) {
	case TYPE_INT:
		emit(ctx, "uint32_t %s;\n", param->p_name);
		break;
	case TYPE_HANDLE:
		emit(ctx, "kern_handle_t %s;\n", param->p_name);
		break;
	case TYPE_SIZE:
		emit(ctx, "uint64_t %s;\n", param->p_name);
		break;
	case TYPE_STRING:
	case TYPE_BUFFER:
		emit(ctx, "uint16_t %s_offset;\n", param->p_name);
		emit(ctx, "uint16_t %s_len;\n", param->p_name);
		break;
	default:
		break;
	}

	return 0;
}

static int emit_msg_struct_params(
	struct emit_ctx *ctx,
	const struct msg_definition *msg)
{
	b_queue_entry *entry = b_queue_first(&msg->msg_params);
	while (entry) {
		const struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit_msg_struct_member(ctx, param);
		entry = b_queue_next(entry);
	}

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		const struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);

		switch (param->p_type->ty_id) {
		case TYPE_STRING:
			emit(ctx, "uint16_t %s_offset;\n", param->p_name);
			emit(ctx, "uint16_t %s_max;\n", param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx, "uint16_t %s_offset;\n", param->p_name);
			emit(ctx, "uint32_t %s_max;\n", param->p_name);
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	return 0;
}

static int emit_msg_struct_results(
	struct emit_ctx *ctx,
	const struct msg_definition *msg)
{
	b_queue_entry *entry = b_queue_first(&msg->msg_results);
	while (entry) {
		const struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit_msg_struct_member(ctx, param);
		entry = b_queue_next(entry);
	}

	return 0;
}

static int emit_interface_msg_struct(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	const struct msg_definition *msg)
{
	b_string *tmp = b_string_create();

	emit(ctx, "struct %s_%s_msg {\n", iface->if_name, msg->msg_name);
	emit_indent(ctx);

	emit(ctx, "xpc_msg_header_t msg_header;\n");
	emit(ctx, "union {\n");
	emit_indent(ctx);

	/* msg_request inner struct */
	emit(ctx, "struct {\n");
	emit_indent(ctx);

	emit_msg_struct_params(ctx, msg);

	emit_unindent(ctx);
	emit(ctx, "} msg_request;\n");

	/* msg_response inner struct */
	emit(ctx, "struct {\n");
	emit_indent(ctx);

	emit_msg_struct_results(ctx, msg);

	emit_unindent(ctx);
	emit(ctx, "} msg_response;\n");

	emit_unindent(ctx);
	emit(ctx, "};\n");

	emit_unindent(ctx);
	emit(ctx, "};\n");

	b_string_unref(tmp);
	return 0;
}

static int emit_interface_msg_structs(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	b_queue_entry *entry = b_queue_first(&iface->if_msg);
	while (entry) {
		const struct msg_definition *msg
			= b_unbox(struct msg_definition, entry, msg_entry);

		emit_interface_msg_struct(ctx, iface, msg);

		entry = b_queue_next(entry);
	}

	emit(ctx, "\n");
	return 0;
}

static int emit_interface_msg_function_send_impl(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	const struct msg_definition *msg)
{
	b_string *iface_ucase = b_string_create_from_cstr(iface->if_name);
	b_string_toupper(iface_ucase);
	b_string *msg_ucase = b_string_create_from_cstr(msg->msg_name);
	b_string_toupper(msg_ucase);

	emit(ctx,
	     "struct %s_%s_msg msg_data = {0};\n",
	     iface->if_name,
	     msg->msg_name);
	emit(ctx,
	     "xpc_msg_header_init(&msg_data.msg_header, INTERFACE_%s, "
	     "MSG_%s_%s);\n",
	     b_string_ptr(iface_ucase),
	     b_string_ptr(iface_ucase),
	     b_string_ptr(msg_ucase));

	b_string_unref(iface_ucase);
	b_string_unref(msg_ucase);

	emit(ctx, "uint32_t in_offset = sizeof msg_data;\n\n");
	emit(ctx, "uint32_t out_offset = sizeof msg_data;\n\n");

	size_t nr_req_handles = 0;
	size_t nr_resp_handles = 0;

	b_queue_entry *entry = b_queue_first(&msg->msg_params);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_INT:
		case TYPE_SIZE:
			emit(ctx,
			     "msg_data.msg_request.%s = %s;\n\n",
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx,
			     "msg_data.msg_request.%s = %zu;\n",
			     param->p_name,
			     nr_req_handles);
			nr_req_handles++;
			break;
		case TYPE_STRING:
			emit(ctx,
			     "msg_data.msg_request.%s_offset = in_offset;\n",
			     param->p_name);
			emit(ctx,
			     "msg_data.msg_request.%s_len = strlen(%s);\n",
			     param->p_name,
			     param->p_name);
			emit(ctx,
			     "in_offset += msg_data.msg_request.%s_len;\n",
			     param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx,
			     "msg_data.msg_request.%s_offset = offset;\n",
			     param->p_name);
			emit(ctx,
			     "msg_data.msg_request.%s_len = %s_len;\n",
			     param->p_name,
			     param->p_name);
			emit(ctx,
			     "in_offset += msg_data.msg_request.%s_len;\n",
			     param->p_name);
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_STRING:
		case TYPE_BUFFER:
			emit(ctx,
			     "msg_data.msg_request.%s_offset = out_offset;\n",
			     param->p_name,
			     param->p_name);
			emit(ctx,
			     "msg_data.msg_request.%s_max = out_%s_max;\n",
			     param->p_name,
			     param->p_name);
			emit(ctx, "out_offset += out_%s_max;\n", param->p_name);
			break;
		case TYPE_HANDLE:
			nr_resp_handles++;
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	emit(ctx, "kern_iovec_t req_iov[] = {\n");
	emit_indent(ctx);
	emit(ctx, "IOVEC(&msg_data, sizeof msg_data),\n");
	size_t nr_req_iov = 1;

	entry = b_queue_first(&msg->msg_params);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);

		switch (param->p_type->ty_id) {
		case TYPE_STRING:
		case TYPE_BUFFER:
			emit(ctx,
			     "IOVEC(%s, msg_data.msg_request.%s_len),\n",
			     param->p_name,
			     param->p_name);
			nr_req_iov++;
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	emit_unindent(ctx);
	emit(ctx, "};\n\n");

	if (nr_req_handles) {
		emit(ctx,
		     "kern_msg_handle_t req_handles[%zu] = {0};\n",
		     nr_req_handles);
	}

	emit(ctx, "kern_iovec_t resp_iov[] = {\n");
	emit_indent(ctx);
	emit(ctx, "IOVEC(&msg_data, sizeof msg_data),\n");
	size_t nr_resp_iov = 1;

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);

		switch (param->p_type->ty_id) {
		case TYPE_STRING:
		case TYPE_BUFFER:
			emit(ctx,
			     "IOVEC(out_%s, out_%s_max),\n",
			     param->p_name,
			     param->p_name);
			nr_resp_iov++;
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	emit_unindent(ctx);
	emit(ctx, "};\n\n");

	if (nr_resp_handles) {
		emit(ctx,
		     "kern_msg_handle_t resp_handles[%zu] = {0};\n",
		     nr_resp_handles);
	}

	emit(ctx, "kern_msg_t msg = {\n");
	emit_indent(ctx);
	emit(ctx, ".msg_data = req_iov,\n.msg_data_count = %zu,\n", nr_req_iov);

	if (nr_req_handles) {
		emit(ctx,
		     ".msg_handles = req_handles,\n.msg_handles_count = %zu,",
		     nr_req_handles);
	}

	emit_unindent(ctx);
	emit(ctx, "};\n\n");

	emit(ctx, "kern_msg_t reply = {\n");
	emit_indent(ctx);
	emit(ctx,
	     ".msg_data = resp_iov,\n.msg_data_count = %zu,\n",
	     nr_resp_iov);

	if (nr_resp_handles) {
		emit(ctx,
		     ".msg_handles = resp_handles,\n.msg_handles_count = "
		     "%zu,\n",
		     nr_resp_handles);
	}

	emit_unindent(ctx);
	emit(ctx, "};\n\n");

	emit(ctx, "kern_status_t status = msg_send(port, &msg, &reply);\n");
	emit(ctx, "if (status != KERN_OK) return status;\n\n");
	emit(ctx,
	     "if (msg_data.msg_header.hdr_status != KERN_OK) return "
	     "msg_data.msg_header.hdr_status;\n\n");

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_HANDLE:
			emit(ctx, "*out_%s = ", param->p_name);
			emit(ctx,
			     "msg_data.msg_response.%s < %zu ",
			     param->p_name,
			     nr_resp_handles);
			emit(ctx,
			     "? "
			     "resp_handles[msg_data.msg_response.%s].hnd_"
			     "value ",
			     param->p_name);
			emit(ctx, ": KERN_HANDLE_INVALID;\n");
			break;
		case TYPE_BUFFER:
		case TYPE_STRING:
			break;
		default:
			emit(ctx,
			     "*out_%s = msg_data.msg_response.%s;\n",
			     param->p_name,
			     param->p_name);
			break;
		}

		entry = b_queue_next(entry);
	}

	emit(ctx, "return status;\n");
	return 0;
}

static int emit_interface_msg_function_send(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	const struct msg_definition *msg,
	bool prototype_only)
{
	if (prototype_only) {
		emit(ctx, "extern ");
	}

	emit(ctx, "kern_status_t %s_%s(\n", iface->if_name, msg->msg_name);

	emit_indent(ctx);

	emit(ctx, "kern_handle_t port");

	b_queue_entry *entry = b_queue_first(&msg->msg_params);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit(ctx, ",\n");
		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx, "int %s", param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx, "kern_handle_t %s", param->p_name);
			break;
		case TYPE_SIZE:
			emit(ctx, "size_t %s", param->p_name);
			break;
		case TYPE_STRING:
			emit(ctx, "const char *%s", param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx,
			     "const void *%s, size_t %s_len",
			     param->p_name,
			     param->p_name);
		default:
			break;
		}
		entry = b_queue_next(entry);
	}

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit(ctx, ",\n");
		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx, "int *out_%s", param->p_name);
			break;
		case TYPE_SIZE:
			emit(ctx, "size_t *out_%s", param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx, "kern_handle_t *out_%s", param->p_name);
			break;
		case TYPE_STRING:
			emit(ctx,
			     "char *out_%s,\nsize_t out_%s_max",
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx,
			     "void *out_%s,\nsize_t out_%s_max",
			     param->p_name,
			     param->p_name);
			break;
		default:
			break;
		}
		entry = b_queue_next(entry);
	}

	emit(ctx, ")");
	emit_unindent(ctx);

	if (prototype_only) {
		emit(ctx, ";\n");
		return 0;
	}

	emit(ctx, "\n{\n");
	emit_indent(ctx);

	emit_interface_msg_function_send_impl(ctx, iface, msg);

	emit_unindent(ctx);
	emit(ctx, "}\n\n");

	return 0;
}

static int emit_interface_dispatcher_impl_msg(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	const struct msg_definition *msg)
{
#define MSG_STRUCT_NAME        "__data"
#define MSG_STRUCT_OFFSET_NAME "__data_offset"
	emit(ctx,
	     "if (!vtable->%s) return xpc_msg_reply_error(msg, "
	     "KERN_UNIMPLEMENTED);\n",
	     msg->msg_name);
	emit(ctx,
	     "struct %s_%s_msg " MSG_STRUCT_NAME " = {0};\n",
	     iface->if_name,
	     msg->msg_name);
	emit(ctx,
	     "status = xpc_msg_read(msg, 0, &" MSG_STRUCT_NAME
	     ", sizeof " MSG_STRUCT_NAME ");\n");

	b_queue_entry *entry = b_queue_first(&msg->msg_params);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx,
			     "int %s = " MSG_STRUCT_NAME ".msg_request.%s;\n",
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_SIZE:
			emit(ctx,
			     "size_t %s = " MSG_STRUCT_NAME
			     ".msg_request.%s;\n",
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_STRING:
			emit(ctx,
			     "xpc_string_t %s = "
			     "XPC_STRING_IN(msg, " MSG_STRUCT_NAME
			     ".msg_request.%s_offset, " MSG_STRUCT_NAME
			     ".msg_request.%s_len);\n",
			     param->p_name,
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx,
			     "xpc_string_t %s = "
			     "XPC_BUFFER_IN(msg, " MSG_STRUCT_NAME
			     ".msg_request.%s_offset, " MSG_STRUCT_NAME
			     ".msg_request.%s_len);\n",
			     param->p_name,
			     param->p_name,
			     param->p_name);
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx, "int %s = 0;\n", param->p_name);
			break;
		case TYPE_SIZE:
			emit(ctx, "size_t %s = 0;\n", param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx,
			     "kern_handle_t %s = KERN_HANDLE_INVALID;\n",
			     param->p_name);
			break;
		case TYPE_STRING:
			emit(ctx,
			     "xpc_string_t %s = "
			     "XPC_STRING_OUT(msg, " MSG_STRUCT_NAME
			     ".msg_request.%s_offset, " MSG_STRUCT_NAME
			     ".msg_request.%s_max);\n",
			     param->p_name,
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx,
			     "xpc_buffer_t %s = "
			     "XPC_BUFFER_OUT(msg, " MSG_STRUCT_NAME
			     ".msg_request.%s_offset, " MSG_STRUCT_NAME
			     ".msg_request.%s_max);\n",
			     param->p_name,
			     param->p_name,
			     param->p_name);
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	emit(ctx, "status = vtable->%s(\n", msg->msg_name);
	emit_indent(ctx);
	emit(ctx, "ctx,\n&msg->msg_sender");
	entry = b_queue_first(&msg->msg_params);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);

		switch (param->p_type->ty_id) {
		case TYPE_STRING:
		case TYPE_BUFFER:
			emit(ctx, ",\n&%s", param->p_name);
			break;
		default:
			emit(ctx, ",\n%s", param->p_name);
			break;
		}

		entry = b_queue_next(entry);
	}
	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit(ctx, ",\n&%s", param->p_name);

		entry = b_queue_next(entry);
	}

	emit(ctx, ",\narg);\n");
	emit_unindent(ctx);

	emit(ctx,
	     "if (status != KERN_OK) return xpc_msg_reply_error(msg, "
	     "status);\n");

	emit(ctx, MSG_STRUCT_NAME ".msg_header.hdr_status = 0;\n");
	size_t handle_index = 0;
	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx,
			     MSG_STRUCT_NAME ".msg_response.%s = %s;\n",
			     param->p_name,
			     param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx,
			     MSG_STRUCT_NAME ".msg_response.%s = %zu;\n",
			     param->p_name,
			     handle_index);
			handle_index++;
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}

	emit(ctx,
	     "kern_iovec_t iov = IOVEC(&" MSG_STRUCT_NAME
	     ", sizeof " MSG_STRUCT_NAME ");\n");

	emit(ctx, "kern_msg_handle_t out_handles[] = {\n");
	emit_indent(ctx);
	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		switch (param->p_type->ty_id) {
		case TYPE_HANDLE:
			emit(ctx,
			     "MSG_HANDLE(KERN_MSG_HANDLE_MOVE, %s),\n",
			     param->p_name);
			break;
		default:
			break;
		}

		entry = b_queue_next(entry);
	}
	emit_unindent(ctx);
	emit(ctx, "};\n");

	emit(ctx,
	     "status = xpc_msg_reply(msg, &iov, 1, out_handles, sizeof "
	     "out_handles / sizeof out_handles[0]);\n");

	return 0;
}

static int emit_interface_dispatcher_impl(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	b_string *iface_ucase = b_string_create_from_cstr(iface->if_name);
	b_string_toupper(iface_ucase);
	b_string *msg_ucase = b_string_create();

	emit(ctx,
	     "if (msg->msg_header.hdr_interface != INTERFACE_%s) return "
	     "KERN_INVALID_ARGUMENT;\n\n",
	     b_string_ptr(iface_ucase));

	emit(ctx, "kern_status_t status = KERN_OK;\n");
	emit(ctx, "switch (msg->msg_header.hdr_func) {\n");

	b_queue_entry *entry = b_queue_first(&iface->if_msg);
	while (entry) {
		const struct msg_definition *msg
			= b_unbox(struct msg_definition, entry, msg_entry);

		b_string_clear(msg_ucase);
		b_string_append_cstr(msg_ucase, msg->msg_name);
		b_string_toupper(msg_ucase);

		emit(ctx,
		     "case MSG_%s_%s: {\n",
		     b_string_ptr(iface_ucase),
		     b_string_ptr(msg_ucase));
		emit_indent(ctx);
		emit_interface_dispatcher_impl_msg(ctx, iface, msg);
		emit(ctx, "break;\n");
		emit_unindent(ctx);
		emit(ctx, "}\n");

		entry = b_queue_next(entry);
	}

	b_string_unref(iface_ucase);

	emit(ctx, "default:\n");
	emit_indent(ctx);
	emit(ctx, "status = KERN_INVALID_ARGUMENT;\nbreak;\n");
	emit_unindent(ctx);
	emit(ctx, "}\n\nreturn status;\n");

	return 0;
}

static int emit_interface_dispatcher(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	bool prototype_only)
{
	if (prototype_only) {
		emit(ctx, "extern ");
	}

	emit(ctx, "kern_status_t %s_dispatch(\n", iface->if_name);
	emit_indent(ctx);
	emit(ctx, "xpc_context_t *ctx,\n");
	emit(ctx, "const xpc_msg_t *msg,\n");
	emit(ctx, "const struct %s_vtable *vtable,\n", iface->if_name);
	emit(ctx, "void *arg)");
	emit_unindent(ctx);

	if (prototype_only) {
		emit(ctx, ";\n");
		return 0;
	}

	emit(ctx, "\n{\n");
	emit_indent(ctx);

	emit_interface_dispatcher_impl(ctx, iface);

	emit_unindent(ctx);
	emit(ctx, "}\n\n");

	return 0;
}

static int emit_interface_functions(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	bool prototype_only)
{
	b_queue_entry *entry = b_queue_first(&iface->if_msg);
	while (entry) {
		const struct msg_definition *msg
			= b_unbox(struct msg_definition, entry, msg_entry);

		emit_interface_msg_function_send(
			ctx,
			iface,
			msg,
			prototype_only);

		entry = b_queue_next(entry);
	}

	emit_interface_dispatcher(ctx, iface, prototype_only);

	return 0;
}

static int emit_interface_vtable_entry(
	struct emit_ctx *ctx,
	const struct interface_definition *iface,
	const struct msg_definition *msg)
{
	emit(ctx, "kern_status_t(*%s)(\n", msg->msg_name);
	emit_indent(ctx);
	emit(ctx, "xpc_context_t *ctx,\n");
	emit(ctx, "const xpc_endpoint_t *sender");

	size_t i = 0;
	b_queue_entry *entry = b_queue_first(&msg->msg_params);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit(ctx, ",\n");

		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx, "int %s", param->p_name);
			break;
		case TYPE_SIZE:
			emit(ctx, "size_t %s", param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx, "const xpc_buffer_t *%s", param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx, "kern_handle_t %s", param->p_name);
			break;
		case TYPE_STRING:
			emit(ctx, "const xpc_string_t *%s", param->p_name);
			break;
		default:
			break;
		}

		i++;
		entry = b_queue_next(entry);
	}

	entry = b_queue_first(&msg->msg_results);
	while (entry) {
		struct msg_parameter *param
			= b_unbox(struct msg_parameter, entry, p_entry);
		emit(ctx, ",\n");

		switch (param->p_type->ty_id) {
		case TYPE_INT:
			emit(ctx, "int *out_%s", param->p_name);
			break;
		case TYPE_HANDLE:
			emit(ctx, "kern_handle_t *out_%s", param->p_name);
			break;
		case TYPE_STRING:
			emit(ctx, "xpc_string_t *out_%s", param->p_name);
			break;
		case TYPE_SIZE:
			emit(ctx, "size_t *out_%s", param->p_name);
			break;
		case TYPE_BUFFER:
			emit(ctx, "xpc_buffer_t *out_%s", param->p_name);
			break;
		default:
			break;
		}

		i++;
		entry = b_queue_next(entry);
	}

	if (i > 0) {
		emit(ctx, ",\n");
	}

	emit(ctx, "void *");

	emit(ctx, ");\n", msg->msg_name);
	emit_unindent(ctx);

	return 0;
}

static int emit_interface_vtable(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	emit(ctx, "struct %s_vtable {\n", iface->if_name);
	emit_indent(ctx);

	b_queue_entry *entry = b_queue_first(&iface->if_msg);
	while (entry) {
		const struct msg_definition *msg
			= b_unbox(struct msg_definition, entry, msg_entry);

		emit_interface_vtable_entry(ctx, iface, msg);

		entry = b_queue_next(entry);
	}

	emit_unindent(ctx);
	emit(ctx, "};\n\n");
	return 0;
}

static int emit_header(
	struct emit_ctx *ctx,
	const struct interface_definition *iface)
{
	emit_header_guard_start(ctx, iface);
	emit_include(ctx, "stdint.h", true);
	emit_include(ctx, "stddef.h", true);
	emit_include(ctx, "string.h", true);
	emit_include(ctx, "xpc/endpoint.h", true);
	emit_include(ctx, "xpc/msg.h", true);
	emit_include(ctx, "xpc/string.h", true);
	emit_include(ctx, "xpc/buffer.h", true);
	emit_include(ctx, "xpc/context.h", true);
	emit_include(ctx, "mango/msg.h", true);
	emit_include(ctx, "mango/types.h", true);
	emit(ctx, "\n");

	emit_interface_id_macros(ctx, iface);
	emit_interface_vtable(ctx, iface);
	emit_interface_msg_structs(ctx, iface);
	emit_interface_functions(ctx, iface, true);

	emit(ctx, "\n#if defined(MSG_IMPLEMENTATION)\n");

	emit_interface_functions(ctx, iface, false);

	emit(ctx, "#endif\n");

	emit_header_guard_end(ctx, iface);
	return 0;
}

static int emit_interface(const struct interface_definition *iface)
{
	char path[4096];
	b_file *file = NULL;

	snprintf(path, sizeof path, "%s.h", iface->if_name);
	b_result result = b_file_open(
		NULL,
		B_RV_PATH(path),
		B_FILE_WRITE_ONLY | B_FILE_CREATE,
		&file);
	if (b_result_is_error(result)) {
		b_throw(result);
		fprintf(stderr, "cannot create C header file %s\n", path);
		return -1;
	}

	struct emit_ctx ctx = {
		.ctx_out = file,
		.ctx_max_handle_params = get_max_handle_params(iface),
	};

	int err = emit_header(&ctx, iface);
	b_file_unref(file);

	return err;
}

static struct backend backend = {
	.b_name = "c-mpc",
	.b_emit = emit_interface,
};

const struct backend *c_mpc_backend(void)
{
	return &backend;
}