#include <bshell/command/command.h>
#include <bshell/command/native-command.h>
#include <bshell/format.h>
#include <bshell/runtime/pipeline.h>
#include <bshell/status.h>
#include <fx/diagnostics/process.h>
#include <fx/reflection/function.h>
#include <fx/string.h>
#include <fx/vector.h>

enum {
	F_REDIRECT_STDIN = 0x01u,
	F_REDIRECT_STDOUT = 0x02u,
};

struct bshell_native_command_p {
	int cmd_flags;
	fx_string *cmd_path;
	fx_stringstream *cmd_tmp;
	fx_process *cmd_proc;
	struct bshell_value_writer cmd_writer;
	bool cmd_writer_init;
};

static void init(fx_object *obj, void *priv)
{
	struct bshell_native_command_p *cmd_p = priv;
	cmd_p->cmd_tmp = fx_stringstream_create();
}

static void fini(fx_object *obj, void *priv)
{
	struct bshell_native_command_p *cmd_p = priv;
	fx_stringstream_unref(cmd_p->cmd_tmp);
	fx_string_unref(cmd_p->cmd_path);
}

static enum bshell_status start_process(bshell_native_command *cmd, int flags)
{
	struct bshell_native_command_p *cmd_p
		= fx_object_get_private(cmd, BSHELL_TYPE_NATIVE_COMMAND);
	fx_stringstream *tmp = fx_stringstream_create();
	size_t argc = bshell_command_get_arg_count(cmd);
	char **argv = calloc(argc, sizeof *argv);

	for (size_t i = 0; i < argc; i++) {
		const fx_value *arg = bshell_command_get_arg(cmd, i);

		fx_stringstream_reset(tmp);
		fx_value_to_string(arg, tmp, NULL);
		argv[i] = fx_stringstream_steal(tmp);
	}
	fx_stringstream_unref(tmp);

	fx_process *self = fx_process_get_self();

	fx_process_start_info info = {
		.proc_args = (const char **)argv,
		.proc_args_count = argc,
		.proc_file_name = fx_string_get_cstr(cmd_p->cmd_path),
		.proc_environment = fx_process_get_environment(self),
	};

	if (flags & F_REDIRECT_STDIN) {
		info.proc_redirect_stdin = true;
	}

	if (flags & F_REDIRECT_STDOUT) {
		info.proc_redirect_stdout = true;
	}

	cmd_p->cmd_flags = flags;
	cmd_p->cmd_proc = fx_process_create(&info);

	fx_status status = fx_process_start(cmd_p->cmd_proc);
	for (size_t i = 0; i < argc; i++) {
		free(argv[i]);
	}
	free(argv);

	if (!FX_OK(status)) {
		return BSHELL_ERR_NO_MEMORY;
	}

	return BSHELL_SUCCESS;
}

static enum bshell_status begin_processing(
	bshell_command *cmd,
	enum bshell_command_position position)
{
	struct bshell_native_command_p *cmd_p
		= fx_object_get_private(cmd, BSHELL_TYPE_NATIVE_COMMAND);
	int flags = 0;
	switch (position) {
	case BSHELL_COMMAND_POSITION_BEGINNING:
		flags = F_REDIRECT_STDOUT;
		break;
	case BSHELL_COMMAND_POSITION_MIDDLE:
		flags = F_REDIRECT_STDIN | F_REDIRECT_STDOUT;
		break;
	case BSHELL_COMMAND_POSITION_END:
		flags = F_REDIRECT_STDIN;
		break;
	default:
		break;
	}

	return start_process(cmd, flags);
}

static enum bshell_status process_record(
	bshell_command *cmd,
	bshell_pipeline *pipeline,
	struct bshell_runtime *rt)
{
	struct bshell_native_command_p *cmd_p
		= fx_object_get_private(cmd, BSHELL_TYPE_NATIVE_COMMAND);

	if (cmd_p->cmd_flags & F_REDIRECT_STDIN) {
		fx_value in = bshell_pipeline_read_value(pipeline);
		if (!fx_value_is_set(&in)) {
			return BSHELL_SUCCESS;
		}

		fx_stream *in_stream = fx_process_get_stdin(cmd_p->cmd_proc);
		if (!cmd_p->cmd_writer_init) {
			bshell_value_writer_init(&cmd_p->cmd_writer, in_stream);
			cmd_p->cmd_writer_init = true;
		}

		bshell_value_writer_write(&cmd_p->cmd_writer, &in);
		fx_value_unset(&in);
	}

	if (cmd_p->cmd_flags & F_REDIRECT_STDOUT) {
		fx_stream *out_stream = fx_process_get_stdout(cmd_p->cmd_proc);
		fx_stringstream_reset(cmd_p->cmd_tmp);
		fx_status status
			= fx_stream_read_line_s(out_stream, cmd_p->cmd_tmp);
		if (!FX_OK(status)) {
			/* no more data available */
			return BSHELL_SUCCESS;
		}

		fx_string *record = fx_string_create_from_cstr(
			fx_stringstream_get_cstr(cmd_p->cmd_tmp));
		bshell_pipeline_write_value(
			pipeline,
			FX_VALUE_OBJECT(record),
			false);
		fx_string_unref(record);
	}

	return BSHELL_SUCCESS;
}

static enum bshell_status end_processing(bshell_command *cmd)
{
	struct bshell_native_command_p *cmd_p
		= fx_object_get_private(cmd, BSHELL_TYPE_NATIVE_COMMAND);
	if (cmd_p->cmd_writer_init) {
		bshell_value_writer_cleanup(&cmd_p->cmd_writer);
		cmd_p->cmd_writer_init = false;
	}

	if (cmd_p->cmd_proc) {
		fx_process_close_stdin(cmd_p->cmd_proc);
		fx_process_close_stdout(cmd_p->cmd_proc);
		fx_process_close_stderr(cmd_p->cmd_proc);

		int result = 0;
		fx_process_wait(cmd_p->cmd_proc, &result);
		fx_process_unref(cmd_p->cmd_proc);
		cmd_p->cmd_proc = NULL;
	}

	return BSHELL_SUCCESS;
}

static enum bshell_status get_callable_name(
	const bshell_native_command *cmd,
	fx_string *out)
{
	struct bshell_native_command_p *cmd_p
		= fx_object_get_private(cmd, BSHELL_TYPE_NATIVE_COMMAND);
	fx_string_append_s(out, cmd_p->cmd_path);
	return BSHELL_SUCCESS;
}

bshell_native_command *bshell_native_command_create(const char *path)
{
	bshell_native_command *out
		= fx_object_create(BSHELL_TYPE_NATIVE_COMMAND);
	if (!out) {
		return NULL;
	}

	struct bshell_native_command_p *cmd
		= fx_object_get_private(out, BSHELL_TYPE_NATIVE_COMMAND);
	cmd->cmd_path = fx_string_create_from_cstr(path);

	return out;
}

FX_TYPE_CLASS_BEGIN(bshell_native_command)
	FX_TYPE_VTABLE_INTERFACE_BEGIN(fx_object, FX_TYPE_OBJECT)
		FX_INTERFACE_ENTRY(to_string) = NULL;
	FX_TYPE_VTABLE_INTERFACE_END(fx_object, FX_TYPE_OBJECT)

	FX_TYPE_VTABLE_INTERFACE_BEGIN(bshell_command, BSHELL_TYPE_COMMAND)
		FX_INTERFACE_ENTRY(c_command_type) = "Native-Command";
		FX_INTERFACE_ENTRY(c_get_callable_name) = get_callable_name;
		FX_INTERFACE_ENTRY(c_begin_processing) = begin_processing;
		FX_INTERFACE_ENTRY(c_process_record) = process_record;
		FX_INTERFACE_ENTRY(c_end_processing) = end_processing;
	FX_TYPE_VTABLE_INTERFACE_END(bshell_command, BSHELL_TYPE_COMMAND)
FX_TYPE_CLASS_END(bshell_native_command)

FX_TYPE_DEFINITION_BEGIN(bshell_native_command)
	FX_TYPE_ID(0x720ede87, 0xe586, 0x495a, 0xa229, 0x1505c01b5714);
	FX_TYPE_FLAGS(FX_TYPE_F_ABSTRACT);
	FX_TYPE_NAME("bshell.runtime.native_command");
	FX_TYPE_EXTENDS(BSHELL_TYPE_COMMAND);
	FX_TYPE_CLASS(bshell_native_command_class);
	FX_TYPE_INSTANCE_INIT(init);
	FX_TYPE_INSTANCE_FINI(fini);
	FX_TYPE_INSTANCE_PRIVATE(struct bshell_native_command_p);
FX_TYPE_DEFINITION_END(bshell_native_command)