#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

#include <node/node_api.h>
#include <sqlite3.h>


static napi_value ffi_open(napi_env env, napi_callback_info info);
static napi_value ffi_exec(napi_env env, napi_callback_info info);
static napi_value ffi_all (napi_env env, napi_callback_info info);
static napi_value ffi_run (napi_env env, napi_callback_info info);


struct NAPIContext {
	napi_env env;
	napi_value value;
	uint32_t index;
};

struct Fn {
	const char *const label;
	napi_value(*const handle)(napi_env env, napi_callback_info info);
};

static const struct Fn fns[] = {
	{ .label = "open", .handle = ffi_open, },
	{ NULL, NULL },
};

struct Fn methods[] = {
	{ .label = "exec", .handle = ffi_exec, },
	{ .label = "all",  .handle = ffi_all,  },
	{ .label = "run",  .handle = ffi_run,  },
	{ NULL, NULL },
};

static const napi_type_tag SQLITE_DB_TYPE_TAG = {
	0x0e9614d459f746cc, 0x88b814a5dc5c4cf7
};

static const int
SQLITE_OPEN_FLAGS =
	/*
	   From https://www.sqlite.org/c3ref/open.html:

	   > The database is opened for reading and writing, and is created if
	   > it does not already exist.  This is the behavior that is always
	   > used for sqlite3_open() and sqlite3_open16().
	*/
	SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |

	/*
	   From https://www.sqlite.org/c3ref/open.html:

	   > The new database connection will use the "serialized" threading
	   > mode.  This means the multiple threads can safely attempt to use
	   > the same database connection at the same time.  (Mutexes will block
	   > any actual concurrency, but in this mode there is no harm in
	   > trying.)
	*/
	SQLITE_OPEN_FULLMUTEX |

	/*
	   From https://www.sqlite.org/c3ref/open.html:

	   > The database connection comes up in "extended result code mode".
	   > In other words, the database behaves has if
	   > sqlite3_extended_result_codes(db,1) where called on the database
	   > connection as soon as the connection is created.  In addition to
	   > setting the extended result code mode, this flag also causes
	   > sqlite3_open_v2() to return an extended result code.

	   From https://www.sqlite.org/c3ref/extended_result_codes.html:

	   > The sqlite3_extended_result_codes() routine enables or disables the
	   > extended result codes feature of SQLite.  The extended result codes
	   > are disabled by default for historical compatibility.
	*/
	SQLITE_OPEN_EXRESCODE;


static const char *const
FIX_SQLITE_PRAGMAS =
	/*
	   From https://research.cs.wisc.edu/adsl/Publications/alice-osdi14.pdf:

	   > Similarly, SQLite does not provide durability under the default
	   > journal-mode (we became aware of this only after interacting with
	   > developers), but its documentation seems misleading.
	   >
	   > (...)
	   >
	   > The developers suggest the SQLite vulnerability is actually not a
	   > behavior guaranteed by SQLite (specifically, that durability cannot
	   > be achieved under rollback journaling); we believe the
	   > documentation is misleading.
	   >
	   > (...)
	   >
	   > Unclear documentation of application guarantees contributes to the
	   > confusion about crash vulnerabilities. During discussions with
	   > developers about durability vulnerabilities, we found that SQLite,
	   > which proclaims itself as fully ACID-complaint, does not provide
	   > durability (even optionally) with the default storage engine,
	   > though the documentation suggests it does.
	*/
	"PRAGMA journal_mode = WAL;\n"
	"PRAGMA synchronous  = EXTRA;\n"

	/*
	   From https://www.sqlite.org/foreignkeys.html:

	   > Foreign key constraints are disabled by default (for backwards
	   > compatibility), so must be enabled separately for each database
	   > connection.
	*/
	"PRAGMA foreign_keys = ON;\n"
	;


// FIXME: make this async
static napi_value
ffi_exec(napi_env env, napi_callback_info info) {
	size_t argc = 1;
	napi_value argv[1];
	int sqlite_rc;
	napi_status napi_rc;
	char *sql = NULL;
	size_t sql_size1;
	size_t sql_size2;
	sqlite3 *db_handle = NULL;
	char *error_msg = NULL;

	napi_rc = napi_get_cb_info(
		env,
		info,
		&argc,
		argv,
		NULL,
		(void *)&db_handle
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"111TODO ERRCODE",
			"Failed to parse arguments TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(env, argv[0], NULL, 0, &sql_size1);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"222TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}

	if (sql_size1 == SIZE_MAX) {
		napi_throw_error(
			env,
			"SQLITE_EOVERFLOW",
			"TODO "
		);
		goto out;
	}
	sql_size1++;  // include the NULL-terminator in size measurement

	sql = malloc(sql_size1);
	if (!sql) {
		napi_throw_error(
			env,
			"SQLITE_ENOMEM",
			"TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(
		env,
		argv[0],
		sql,
		sql_size1,
		&sql_size2
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}
	assert(sql_size1 == sql_size2 + 1 &&
		"Unstable behaviour from Node-API");
	assert(sql);

	sqlite_rc = sqlite3_exec(
		db_handle,
		sql,
		NULL,
		NULL,
		&error_msg
	);
	if (sqlite_rc != SQLITE_OK) {
		napi_throw_error(
			env,
			"3iii33TODO ERRCODE",
			sqlite3_errstr(sqlite_rc)
		);
		goto out;
	}

out:
	if (error_msg) {
		sqlite3_free(error_msg);
	}
	if (sql) {
		free(sql);
	}
	return NULL;
}


static int
accumulate_all_results(
	void *ctxptr,
	int argc,
	char **argv,
	char **column_names
) {
	int rc = 0;

	napi_status napi_rc;
	napi_value row = NULL;

	struct NAPIContext *ctx = ctxptr;
	napi_env   env     = ctx->env;
	napi_value results = ctx->value;
	uint32_t   index   = ctx->index;

	napi_rc = napi_create_object(env, &row);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"TODO  i18n"
		);
		rc = -1;
		goto out;
	}

	for (int i = 0; i < argc; i++) {
		const char *const column_name  = column_names[i];
		const char *const column_value = argv[i];

		// printf("column_name:  %s\n", column_name);
		// printf("column_value: %s\n", column_value);

		napi_value str; // FIXME: dispatch on the type
		napi_rc = napi_create_string_utf8(
			env,
			column_value,
			NAPI_AUTO_LENGTH,
			&str
		);
		if (napi_rc != napi_ok) {
			napi_throw_error(
				env,
				"SQLITE_MiiiETHOD_CREATE",
				"TODO  i18n"
			);
			rc = -1;
			goto out;
		}

		napi_rc = napi_set_named_property(
			env,
			row,
			column_name,
			str
		);
		if (napi_rc != napi_ok) {
			napi_throw_error(
				env,
				"iSQLITE_MiETHOD_CREATE",
				"TODO  i18n"
			);
			rc = -1;
			goto out;
		}
	}

	napi_rc = napi_set_element(
		env,
		results,
		index,
		row
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"TODO  i18n"
		);
		rc = -1;
		goto out;
	}

	ctx->index++;

out:
	return rc;
}

static napi_value
ffi_all(napi_env env, napi_callback_info info) {
	napi_value ret = NULL;

	size_t argc = 1;
	napi_value argv[1];
	int sqlite_rc;
	napi_status napi_rc;
	char *sql = NULL;
	size_t sql_size1;
	size_t sql_size2;
	sqlite3 *db_handle = NULL;
	char *error_msg = NULL;
	napi_value results_array = NULL;

	napi_rc = napi_get_cb_info(
		env,
		info,
		&argc,
		argv,
		NULL,
		(void *)&db_handle
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"111TODO ERRCODE",
			"Failed to parse arguments TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(env, argv[0], NULL, 0, &sql_size1);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"222TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}

	if (sql_size1 == SIZE_MAX) {
		napi_throw_error(
			env,
			"SQLITE_EOVERFLOW",
			"TODO "
		);
		goto out;
	}
	sql_size1++;  // include the NULL-terminator in size measurement

	sql = malloc(sql_size1);
	if (!sql) {
		napi_throw_error(
			env,
			"SQLITE_ENOMEM",
			"TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(
		env,
		argv[0],
		sql,
		sql_size1,
		&sql_size2
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}
	assert(sql_size1 == sql_size2 + 1 &&
		"Unstable behaviour from Node-API");
	assert(sql);

	napi_rc = napi_create_array(env, &results_array);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}

	struct NAPIContext ctx = {
		.env   = env,
		.value = results_array,
		.index = 0,
	};
	sqlite_rc = sqlite3_exec(
		db_handle,
		sql,
		accumulate_all_results,
		&ctx,
		&error_msg
	);
	if (sqlite_rc != SQLITE_OK) {
		napi_throw_error(
			env,
			"i3iiii33TODO ERRCODE",
			sqlite3_errstr(sqlite_rc)
		);
		goto out;
	}

	ret = results_array;

out:
	if (error_msg) {
		sqlite3_free(error_msg);
	}
	if (sql) {
		free(sql);
	}
	return ret;
}

static napi_value
ffi_run(napi_env env, napi_callback_info info) {
	napi_value ret = NULL;

	size_t argc = 1;
	napi_value argv[1];
	int sqlite_rc;
	napi_status napi_rc;
	char *sql = NULL;
	size_t sql_size1;
	size_t sql_size2;
	sqlite3 *db_handle = NULL;
	char *error_msg = NULL;
	napi_value results_array = NULL;

	napi_rc = napi_get_cb_info(
		env,
		info,
		&argc,
		argv,
		NULL,
		(void *)&db_handle
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"111TODO ERRCODE",
			"Failed to parse arguments TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(env, argv[0], NULL, 0, &sql_size1);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"222TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}

	if (sql_size1 == SIZE_MAX) {
		napi_throw_error(
			env,
			"SQLITE_EOVERFLOW",
			"TODO "
		);
		goto out;
	}
	sql_size1++;  // include the NULL-terminator in size measurement

	sql = malloc(sql_size1);
	if (!sql) {
		napi_throw_error(
			env,
			"SQLITE_ENOMEM",
			"TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(
		env,
		argv[0],
		sql,
		sql_size1,
		&sql_size2
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}
	assert(sql_size1 == sql_size2 + 1 &&
		"Unstable behaviour from Node-API");
	assert(sql);

	napi_rc = napi_create_array(env, &results_array);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}

	struct NAPIContext ctx = {
		.env   = env,
		.value = results_array,
		.index = 0,
	};
	sqlite_rc = sqlite3_exec(
		db_handle,
		sql,
		accumulate_all_results,
		&ctx,
		&error_msg
	);
	if (sqlite_rc != SQLITE_OK) {
		napi_throw_error(
			env,
			"i3iiii33TODO ERRCODE",
			sqlite3_errstr(sqlite_rc)
		);
		goto out;
	}

	ret = results_array;

out:
	if (error_msg) {
		sqlite3_free(error_msg);
	}
	if (sql) {
		free(sql);
	}
	return ret;
}

static void
finalize_db_handle(napi_env env, void *finalize_data, void *finalize_hint) {
	(void)finalize_hint;
	sqlite3 *db_handle = finalize_data;
	int sqlite_rc;

	sqlite_rc = sqlite3_close(db_handle);
	if (sqlite_rc != SQLITE_OK) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			sqlite3_errstr(sqlite_rc)
		);
		goto out;
	}

out:
	return;
}

static napi_value
ffi_open(napi_env env, napi_callback_info info) {
	napi_value ret = NULL;

	size_t argc = 1;
	napi_value argv[1];
	int sqlite_rc;
	napi_status napi_rc;
	char *filename = NULL;
	size_t filename_size1;
	size_t filename_size2;
	sqlite3 *db_handle = NULL;
	napi_value wrapped_db_handle = NULL;
	char *error_msg = NULL;

	napi_rc = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Failed to parse arguments TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(
		env,
		argv[0],
		NULL, // FIXME: what is this?
		0, // FIXME: what is this?
		&filename_size1
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}

	if (filename_size1 == SIZE_MAX) {
		napi_throw_error(
			env,
			"SQLITE_EOVERFLOW",
			"TODO "
		);
		goto out;
	}
	filename_size1++;  // include the NULL-terminator in size measurement

	filename = malloc(filename_size1);
	if (!filename) {
		napi_throw_error(
			env,
			"SQLITE_ENOMEM",
			"TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_get_value_string_utf8(
		env,
		argv[0],
		filename,
		filename_size1,
		&filename_size2
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"Invalid number was passed as argument TODO  i18n"
		);
		goto out;
	}
	assert(filename_size1 == filename_size2 + 1 &&
		"Unstable behaviour from Node-API");
	assert(filename);

	sqlite_rc = sqlite3_open_v2(
		filename,
		&db_handle,
		SQLITE_OPEN_FLAGS,
		NULL
	);
	if (sqlite_rc != SQLITE_OK) {
		napi_throw_error(
			env,
			"3i33TODO ERRCODE",
			sqlite3_errstr(sqlite_rc)
		);
		goto out;
	}

	sqlite_rc = sqlite3_exec(
		db_handle,
		FIX_SQLITE_PRAGMAS,
		NULL,
		NULL,
		&error_msg
	);
	if (sqlite_rc != SQLITE_OK) {
		napi_throw_error(
			env,
			"3ii33TODO ERRCODE",
			sqlite3_errstr(sqlite_rc)
		);
		goto out;
	}


	// FIXME: setup the global error log:
	// https://www.sqlite.org/errlog.html

	napi_rc = napi_create_object(env, &wrapped_db_handle);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_type_tag_object(
		env,
		wrapped_db_handle,
		&SQLITE_DB_TYPE_TAG
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"TODO  i18n"
		);
		goto out;
	}

	napi_rc = napi_wrap(
		env,
		wrapped_db_handle,
		db_handle,
		finalize_db_handle,
		NULL,
		NULL
	);
	if (napi_rc != napi_ok) {
		napi_throw_error(
			env,
			"TODO ERRCODE",
			"TODO  i18n"
		);
		goto out;
	}

	for (size_t i = 0; methods[i].label && methods[i].handle; i++) {
		napi_value fn;
		napi_rc = napi_create_function(
			env,
			methods[i].label,
			NAPI_AUTO_LENGTH,
			methods[i].handle,
			db_handle,
			&fn
		);
		if (napi_rc != napi_ok) {
			napi_throw_error(
				env,
				"SQLITE_MiiETHOD_CREATE",
				"TODO  i18n"
			);
			goto out;
		}

		napi_rc = napi_set_named_property(
			env,
			wrapped_db_handle,
			methods[i].label,
			fn
		);
		if (napi_rc != napi_ok) {
			napi_throw_error(
				env,
				"SQLITE_METHOD_SETNAME",
				"TODO  i18n"
			);
			goto out;
		}
	}
	ret = wrapped_db_handle;

out:
	if (error_msg) {
		sqlite3_free(error_msg);
	}
	if (filename) {
		free(filename);
	}
	if (!ret) {
		if (db_handle) {
			if (sqlite3_close(db_handle)) {
				// logerr();
			}
		}
	}
	return ret;
}


static napi_value
ffi_init(napi_env env, napi_value exports) {
	napi_value ret = exports;

	napi_status status;

	for (size_t i = 0; fns[i].label && fns[i].handle; i++) {
		napi_value fn;
		status = napi_create_function(
			env,
			fns[i].label,
			NAPI_AUTO_LENGTH,
			fns[i].handle,
			NULL,
			&fn
		);
		if (status != napi_ok) {
			ret = NULL;
			napi_throw_error(
				env,
				"SQLITE_FN_CREATE",
				"Unable to wrap native function TODO  i18n"
			);
			goto out;
		}

		status = napi_set_named_property(
			env,
			exports,
			fns[i].label,
			fn
		);
		if (status != napi_ok) {
			ret = NULL;
			napi_throw_error(
				env,
				"SQLITE_FN_SETNAME",
				"Unable to populate exports TODO  i18n"
			);
			goto out;
		}
	}

out:
	return ret;
}


NAPI_MODULE_INIT() {
	return ffi_init(env, exports);
}