#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>

#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/parserInternals.h>

#ifdef _WIN32

#include <mysql.h>

#else

#include <mysql/mysql.h>

#endif

#include "hashtable.h"
#include "string_buf.h"

#define X(type, name) type,
#define Y(type, name) X(type, name)

enum field_type {
#include "field_types.c"
};

const enum field_type field_type_ids[] = {
#include "field_types.c"
};

#undef X
#undef Y

#define X(type, name) [type] = #type,
#define Y(type, name) X(type, name)

static const char *const field_enum_names[] = {
#include "field_types.c"
};

#undef X
#undef Y

#define X(type, name) [type] = name,
#define Y(type, name) X(type, name)

static const char *const field_names[] = {
#include "field_types.c"
};

#undef X
#undef Y

static inline bool is_rel_type(enum field_type type)
{
	return type == ONE_TO_ONE_REL || type == MANY_TO_ONE_REL ||
		type == MANY_TO_MANY_REL || type == BROKEN_TO_ONE_REL ||
		type == BROKEN_TO_MANY_REL;
}

static inline bool is_text_type(enum field_type type)
{
	return type == CHAR_FIELD || type == FILE_FIELD || type == TEXT_FIELD;
}

/* All keys and values are static, ht_destroy() is enough to free this. */
static int make_field_names_ht(hashtable_t *ht)
{
	int ret;
	int i;

	ret = ht_string_init(ht);
	if (ret)
		return ret;

	for (i = 0; i < sizeof(field_type_ids) / sizeof(*field_type_ids); i++) {
		ret = ht_add(ht, field_names[i], &field_type_ids[i]);
		if (ret) {
			ht_destroy(ht);
			break;
		}
	}

	return ret;
}

inline static void *create_struct_with_string(size_t minimum_size,
					      size_t char_field_offset,
					      const char *string)
{
	size_t string_size = strlen(string) + 1;
	size_t dynamic_size = char_field_offset + string_size;
	char *mem;

	mem = malloc(dynamic_size > minimum_size ? dynamic_size : minimum_size);
	if (mem)
		memcpy(mem + char_field_offset, string, string_size);

	return mem;
}

#define STRUCT_WITH_STRING_CREATOR(fun_name, type, char_field)	\
	static type *fun_name(const char *string)		\
	{							\
		return (type*) create_struct_with_string	\
			(sizeof(type),				\
			 (size_t) ((type*) 0)->char_field,	\
			 string);				\
	}

struct field {
	struct field *next;
	union field_data {
		size_t max_length;
		char *target_table; /* NULL means mtm table creation failure */
		bool array_has_data;
	} spec_data;
	uint8_t type;
	char name[1];
};

STRUCT_WITH_STRING_CREATOR(create_field, struct field, name)

struct table {
	struct field *fields;
	size_t all_rows;
	size_t inserted_rows;
	size_t insertion_errors;
	bool creation_error;
	char name[1];
};

STRUCT_WITH_STRING_CREATOR(create_table, struct table, name)

struct restore {
	size_t errors_count;
	enum {
		PASS_1 = 1,
		PASS_2 = 2
	} pass;
	int nesting;
	bool fatal_error;
	bool creating_table;
	struct table *current_table;
	struct field *current_field;

	char *characters_buf;
	size_t characters_size;
	size_t characters_count; /* in PASS_1 used without _buf and _size */

	char *pk_buf;
	size_t pk_size;
	size_t pk_filled;

	char *stmt_buf;
	size_t stmt_size;
	size_t stmt_filled;

	hashtable_t field_names;

	hashtable_t tables;

	MYSQL *mysql;

	FILE *raport_stream;
};

/*
 * I'm not sure how I should interpret the 'bigger' and 'smaller' when it comes
 * to chars, that may or may not be signed. Anyways, no need to be coherent with
 * the original version because in practice this function is only ever used
 * to check equality.
 */
static int strcmp_replacing_dot(const char *s1, const char *s2)
{
	size_t i = 0;
	int c1, c2;

	while (true) {
		c1 = (int) (unsigned char) s1[i];
		c2 = (int) (unsigned char) s2[i];

		if (c1 == '.')
			c1 = '_';
		if (c2 == '.')
			c2 = '_';

		if (c1 != c2)
			return c1 - c2;

		if (!c1)
			return 0;

		i++;
	}
}

static size_t string_hash_replacing_dot(const void *key_)
{
	size_t i = 0, hash = (size_t) 0xa1bad2dead3beef4;
	char c, shift;
	const char *key = key_;

	do {
		c = key[i++];

		if (c == '.')
			c = '_';

		shift = ((unsigned char) c) % sizeof(size_t);
		hash += ((hash >> shift) |
			 (hash << (sizeof(size_t) - shift))) ^ c;
	} while (c);

	return hash;
}

static void replace_dot(char *s)
{
	do {
		if (*s == '.')
			*s = '_';
	} while (*(s++));
}

static int init_restore_data(struct restore *data, const char *raport_path)
{
	data->errors_count = 0;
	data->pass = PASS_1;
	data->nesting = 0;
	data->fatal_error = false;
	data->creating_table = false;
	data->current_table = NULL;
	data->current_field = NULL;

	data->characters_buf = NULL;
	data->characters_size = 0;
	data->characters_count = 0;

	data->stmt_buf = NULL;
	data->stmt_size = 0;
	data->stmt_filled = 0;

	data->pk_buf = NULL;
	data->pk_size = 0;
	data->pk_filled = 0;

	if (make_field_names_ht(&data->field_names))
		return -1;

	if (ht_init(&data->tables, string_hash_replacing_dot,
		    (int (*)(const void*, const void*)) strcmp_replacing_dot)) {
		ht_destroy(&data->field_names);
		return -1;
	}

	data->raport_stream = raport_path ? fopen(raport_path, "w+") : NULL;

	if (!data->raport_stream) {
		if (raport_path) {
			fprintf(stderr,
				"Nie udalo sie utworzyc pliku raportu\n\n");
		}
		data->raport_stream = stdout;
	}

	data->mysql = NULL;

	return 0;
}

static void free_field(struct field *field)
{
	if (!field)
		return;

	if (is_rel_type(field->type))
		free(field->spec_data.target_table);
	free(field);
}

static void free_table(struct table *table)
{
	struct field *field, *tmp;

	if (!table)
		return;

	field = table->fields;
	while (field) {
		tmp = field->next;
		free_field(field);
		field = tmp;
	}

	free(table);
}

static void free_table_entry(void *key, void *val, void *dummy_arg)
{
	free_table(val);
}

static void destroy_restore_data(struct restore *data)
{
	ht_destroy(&data->field_names);
	ht_map_destroy(&data->tables, NULL, free_table_entry);
	free(data->characters_buf);
	free(data->stmt_buf);
	free(data->pk_buf);
	if (data->raport_stream != stderr)
		fclose(data->raport_stream);
}

static void out_of_memory_error(struct restore *data)
{
	/*
	 * TODO: dodac informacje na jakim etapie dzialania stanelo
	 * i wypisać jakies informacje o dotychczas zrobionych rzeczach.
	 */
	data->fatal_error = true;

	fprintf(data->raport_stream, "Brak pamieci.\n");
}

static void semantic_error(struct restore *data, const char *msg, ...)
{
	va_list ap;

	data->fatal_error = true;

	fprintf(data->raport_stream, "Blad semantyczny xml: ");
	va_start(ap, msg);
	vfprintf(data->raport_stream, msg, ap);
	va_end(ap);
	fputc('\n', data->raport_stream);
}

struct sb_mysql_arg {
	MYSQL *mysql;
	const char *string;
};

static int sb_mysql_escape(char **buf, size_t *buf_len, size_t *buf_filled,
			   void *arg_)
{
	struct sb_mysql_arg *arg = arg_;
	size_t len = strlen(arg->string);

	if (extend_buf(buf, buf_len, buf_filled, len * 2))
		return -1;

	*buf_filled += mysql_real_escape_string(arg->mysql, *buf + *buf_filled,
						arg->string, len);

	return 0;
}

static int sb_name_escape(char **buf, size_t *buf_len, size_t *buf_filled,
			  void *name_)
{
	const unsigned char *name = name_;
	size_t i;

	for (i = 0; name[i]; i++) {
		if (name[i] == '`') {
			if (sb_bytes(buf, buf_len, buf_filled, name, i + 1))
				return -1;
			name += i;
			i = 0;
		}
	}

	return sb_bytes(buf, buf_len, buf_filled, name, i);
}

static bool is_field_compatible(struct restore *data, const char *name,
				enum field_type type, const char *target_table)
{
	struct field *previous = data->current_field;

	return
		!strcmp(previous->name, (const char*) name) &&
		previous->type == type &&
		(!is_rel_type(type) ||
		 !strcmp_replacing_dot(target_table,
				       previous->spec_data.target_table));
}

static void new_field(struct restore *data, const char *name,
		      enum field_type type, const char *target_table)
{
	struct field *field = NULL, **dst;
	size_t table_name_size;

	field = create_field(name);
	if (!field)
		goto fail;

	field->next = NULL;
	field->type = type;
	if (is_rel_type(type)) {
		table_name_size = strlen(target_table) + 1;
		field->spec_data.target_table = malloc(table_name_size);
		if (!field->spec_data.target_table)
			goto fail;
		memcpy(field->spec_data.target_table,
		       target_table, table_name_size);
		replace_dot(field->spec_data.target_table);
	} else if (type == ARRAY_FIELD) {
		field->spec_data.array_has_data = false;
	} else {
		field->spec_data.max_length = 0;
	}

	dst = data->current_field ? &data->current_field->next :
		&data->current_table->fields;
	*dst = field;

	data->current_field = field;
	return;

fail:
	free_field(field);
	out_of_memory_error(data);
}

static void new_table(struct restore *data, const char *table_name)
{
	struct table *table = NULL;

	table = create_table(table_name);
	if (!table)
		goto fail;
	replace_dot(table->name);

	table->creation_error = false;
	table->all_rows = 0;
	table->inserted_rows = 0;
	table->insertion_errors = 0;
	table->fields = NULL;

	if (ht_add(&data->tables, table->name, table))
		goto fail;

	data->creating_table = true;
	data->current_table = table;
	data->current_field = NULL;
	return;

fail:
	free_table(table);
	out_of_memory_error(data);
}

static int find_attrs(const char **attrs, int to_find,
		      const char *const *searched, const char **found)
{
	int i, j; /* `i' iterates through attrs[], `j' through searched */
	int found_count = 0;

	if (!attrs)
		return to_find;

	for (j = 0; j < to_find; j++)
		found[j] = NULL;

	for (i = 0; attrs[i]; i += 2) {
		for (j = 0; j < to_find; j++) {
			if (!found[j] && !strcmp(attrs[i], searched[j])) {
				found_count++;
				found[j] = attrs[i + 1];
				if (to_find == found_count)
					return 0;
			}
		}
	}

	return to_find - found_count;
}

/*
 * TODO: change handle_field(), handle_entry() and other functions below and
 * above not to call exit(), but rather let control return to main().
 */

static void handle_field(struct restore *data, const char *name,
			 const char **attrs)
{
	const char *searched[4] = {"name", "type", "rel", "to"};
	const char *found[4];
	const char *type_name;
	const enum field_type *type;

	data->characters_count = 0;

	if (data->pass == PASS_2)
		return;

	if (strcmp(name, "field")) {
		semantic_error(data, "tag '%s' zamiast 'field' na poziomie 2",
			       name);
		return;
	}

	find_attrs(attrs, 4, searched, found);

	if (!found[0]) {
		semantic_error(data, "brak atrybutu 'name' w polu modelu `%s`",
			       data->current_table->name);
		return;
	}

	type_name = found[2] ? found[2] : found[1] ? found[1] : NULL;
	if (!type_name) {
		semantic_error(data,
			       "brak atrybutu 'type' w polu `%s` modelu `%s`",
			       found[0], data->current_table->name);
		return;
	}

	if (ht_get(&data->field_names, type_name, NULL, (void**) &type)) {
		fprintf(data->raport_stream,
			"nieznany typ '%s' kolumny `%s` tabeli `%s`.\n",
			type_name, found[0], data->current_table->name);
		type = &field_type_ids[UNKNOWN_FIELD];
	}

	if (is_rel_type(*type) && !found[3]) {
		semantic_error(data,
			       "brak atrybutu 'to' w polu `%s` modelu `%s`",
			       found[0], data->current_table->name);
		return;
	}

	if (data->creating_table) {
		new_field(data, found[0], *type, found[3]);
	} else if (!data->current_field) {
		semantic_error(data,
			       "zmienna liczba pol w rekordach modelu `%s`",
			       data->current_table->name);
		return;
	} else if (!is_field_compatible(data, found[0], *type, found[3])){
		semantic_error(data, "niekompatybilne rekordy modelu `%s`",
			       data->current_table->name);
		return;
	}

	return;
}

static void handle_entry(struct restore *data, const char *name,
			 const char **attrs)
{
	const char *searched[2] = {"model", "pk"};
	const char *found[2];
	struct table *table;
	struct sb_mysql_arg sb_arg;
	int ret;

	if (strcmp(name, "object")) {
		semantic_error(data, "tag '%s' zamiast 'object' na poziomie 1",
			       name);
		return;
	}

	find_attrs(attrs, 2, searched, found);

	if (!found[0]) {
		semantic_error(data, "brak atrybutu 'model' w obiekcie");
		return;
	}
	if (!found[1]) {
		semantic_error(data, "brak atrybutu 'pk' w obiekcie");
		return;
	}

	ret = ht_get(&data->tables, found[0], NULL, (void**) &table);

	if (ret == HT_KEY_ABSENT) {
		switch (data->pass) {
		case PASS_1:
			new_table(data, found[0]);
			break;
		case PASS_2:
			goto fail;
		}
	} else {
		data->creating_table = false;
		if (data->pass == PASS_2 && data->current_table != table)
			printf("Wypelnianie tabeli `%s`\n", table->name);
		data->current_table = table; /* not really needed in PASS_1 */
		data->current_field = table->fields;
	}

	if (data->pass != PASS_2)
		return;

	data->pk_filled = 0;
	if (sb_string(&data->pk_buf, &data->pk_size,
		      &data->pk_filled, found[1]))
		goto fail;

	data->stmt_filled = 0;
	sb_arg = (struct sb_mysql_arg) {data->mysql, found[1]};
	if (sb_sprintf(&data->stmt_buf, &data->stmt_size,
		       &data->stmt_filled,
		       "INSERT INTO `%_` VALUES(\n"
		       "'%_'",
		       sb_name_escape, table->name, sb_mysql_escape, &sb_arg))
		goto fail;

	return;

fail:
	data->fatal_error = true;
}

static int insert_to_connector_table(struct restore *data, const char **attrs)
{
	int res = -1;
	struct field *field = data->current_field;
	const char *tab1 = data->current_table->name;
	const char *tab2 = field->spec_data.target_table;
	const char *pk_attr = "pk";
	const char *pk;
	char *stmt_buf = NULL;
	size_t stmt_size = 0, stmt_filled = 0;
	struct sb_mysql_arg sb_arg1, sb_arg2;

	if (!tab2) /* Means error during creation of conenctor table */
		return 0;

	find_attrs(attrs, 1, &pk_attr, &pk);
	if (!pk) {
		semantic_error(data,
			       "Brak atrybutu 'pk' w tagu w relacji wiele-do-wielu.\n");
		goto fail;
	}

	sb_arg1 = (struct sb_mysql_arg) {data->mysql, data->pk_buf};
	sb_arg2 = (struct sb_mysql_arg) {data->mysql, pk};
	if (sb_sprintf(&stmt_buf, &stmt_size, &stmt_filled,
		       "INSERT INTO `%__mtm_%_` VALUES(\n"
		       "'%_',\n"
		       "'%_');",
		       sb_name_escape, tab1, sb_name_escape, tab2,
		       sb_mysql_escape, &sb_arg1,
		       sb_mysql_escape, &sb_arg2))
		goto fail;

	if (mysql_real_query(data->mysql, stmt_buf, stmt_filled)) {
		data->errors_count++;
		if (!data->current_table->insertion_errors++) {
			fprintf(data->raport_stream,
				"Nie udalo sie wstawic elementu do tabeli lacznikowej:\n"
				"Blad %u (%s): %s\n",
				mysql_errno(data->mysql),
				mysql_sqlstate(data->mysql),
				mysql_error(data->mysql));
		}
	}

	res = 0;

fail:
	free(stmt_buf);
	return res;
}

static void startElement_callback(void *user_data, const xmlChar *name_,
				  const xmlChar **attrs_)
{
	const char *name = (const char*) name_;
	const char **attrs = (const char**) attrs_;
	struct restore *data = user_data;

	if (data->fatal_error)
		return;

	switch(data->nesting++) {
	case 0:
		/* We have no interest in the root element */
		return;
	case 1:
		handle_entry(data, name, attrs);
		break;
	case 2:
		handle_field(data, name, attrs);
		break;
	case 3:
		if (data->pass == PASS_2 &&
		    (data->current_field->type == MANY_TO_MANY_REL ||
		     data->current_field->type == BROKEN_TO_MANY_REL) &&
		    insert_to_connector_table(data, attrs))
			goto fail;
	default:
		break;
	}

	return;

fail:
	data->fatal_error = true;
}

static int insert_CHAR_FIELD(struct restore *data)
{
	struct sb_mysql_arg sb_arg;

	if (!data->characters_count &&
	    sb_string(&data->stmt_buf, &data->stmt_size,
		      &data->stmt_filled, ",\nNULL"))
		return -1;

	sb_arg = (struct sb_mysql_arg)
		{data->mysql, data->characters_buf};
	if (data->characters_count &&
	    sb_sprintf(&data->stmt_buf, &data->stmt_size,
		       &data->stmt_filled,
		       ",\n'%_'",
		       sb_mysql_escape, &sb_arg))
		return -1;

	return 0;
}

#define insert_FILE_FIELD         insert_CHAR_FIELD
#define insert_TEXT_FIELD         insert_CHAR_FIELD
#define insert_FILE_FIELD         insert_CHAR_FIELD
#define insert_INT_FIELD          insert_CHAR_FIELD
#define insert_SMALL_INT_FIELD    insert_CHAR_FIELD
#define insert_POSITIVE_INT_FIELD insert_CHAR_FIELD
#define insert_BIG_INT_FIELD      insert_CHAR_FIELD
#define insert_DECIMAL_FIELD      insert_CHAR_FIELD
#define insert_TIME_FIELD         insert_CHAR_FIELD
#define insert_DATETIME_FIELD     insert_CHAR_FIELD
#define insert_DATE_FIELD         insert_CHAR_FIELD
#define insert_JSON_FIELD         insert_CHAR_FIELD
#define insert_ONE_TO_ONE_REL     insert_CHAR_FIELD
#define insert_MANY_TO_ONE_REL    insert_CHAR_FIELD
#define insert_BROKEN_TO_ONE_REL  insert_CHAR_FIELD
#define insert_UNKNOWN_FIELD      insert_CHAR_FIELD

static int insert_BOOL_FIELD(struct restore *data)
{
	const char *value;

	if (data->characters_count && strstr(data->characters_buf, "False"))
		value = ",\nFALSE";
	else if (data->characters_count && strstr(data->characters_buf, "True"))
		value = ",\nTRUE";
	else
		value = ",\nNULL";

	if (sb_string(&data->stmt_buf, &data->stmt_size,
		      &data->stmt_filled, value))
		return -1;

	return 0;
}

static int insert_array_element(struct restore *data, const char *element,
				int *current_id)
{
	int res = -1;
	char *stmt_buf = NULL;
	size_t stmt_size = 0, stmt_filled = 0;
	struct sb_mysql_arg sb_arg1, sb_arg2;

	sb_arg1 = (struct sb_mysql_arg) {data->mysql, data->pk_buf};
	sb_arg2 = (struct sb_mysql_arg) {data->mysql, element};
	if (sb_sprintf(&stmt_buf, &stmt_size, &stmt_filled,
		       "INSERT INTO `%__array_%_` VALUES(\n"
		       "%d,\n"
		       "'%_',\n"
		       "'%_');",
		       sb_name_escape, data->current_table->name,
		       sb_name_escape, data->current_field->name,
		       (*current_id)++,
		       sb_mysql_escape, &sb_arg1,
		       sb_mysql_escape, &sb_arg2))
		goto fail;

	if (mysql_real_query(data->mysql, stmt_buf, stmt_filled)) {
		data->errors_count++;
		if (!data->current_table->insertion_errors++) {
			fprintf(data->raport_stream,
				"Nie udalo sie wstawic elementu danej ARRAY:\n"
				"Blad %u (%s): %s\n",
				mysql_errno(data->mysql),
				mysql_sqlstate(data->mysql),
				mysql_error(data->mysql));
		}
	}

	res = 0;

fail:
	free(stmt_buf);
	return res;
}

static int insert_ARRAY_FIELD(struct restore *data)
{
	char *pos, *string_start;
	unsigned char c;
	int current_id = 0;
	enum {
		NOT_STARTED,
		BEFORE_FIRST_STRING,
		BEFORE_STRING,
		IN_STRING,
		AFTER_STRING,
		FINISHED
	} state = NOT_STARTED;

	for (pos = data->characters_buf; *pos; pos++) {
		c = *pos;

		switch (state) {
		case NOT_STARTED:
			if (isspace(c))
				break;
			if (c == '[') {
				state = BEFORE_FIRST_STRING;
				break;
			}
			goto syntax_fail;
		case BEFORE_FIRST_STRING:
		case BEFORE_STRING:
			if (isspace(c))
				break;
			if (c == '"') {
				state = IN_STRING;
				string_start = pos + 1;
				break;
			}
			if (c == ']' && state == BEFORE_FIRST_STRING) {
				state = FINISHED;
				break;
			}
			goto syntax_fail;
		case IN_STRING:
			if (c != '"' || pos[-1] == '\\')
				break;
			*pos = '\0';
			if (insert_array_element(data, string_start,
						 &current_id))
				goto fail;
			state = AFTER_STRING;
			break;
		case AFTER_STRING:
			if (isspace(c))
				break;
			if (c == ',') {
				state = BEFORE_STRING;
				break;
			}
			if (c == ']') {
				state = FINISHED;
				break;
			}
			goto syntax_fail;
		case FINISHED:
			if (!isspace(c))
				goto syntax_fail;
		}
	}

	if (state != FINISHED)
		goto fail;

	return 0;

syntax_fail:
	fprintf(data->raport_stream,
		"Blad syntaktyczny w danej typu array:\n%s\n",
		data->characters_buf);
fail:
	return -1;
}

static int no_insert_field(struct restore *data)
{
	return 0;
}

/* Deliberately omitted */
#define insert_EMPTY_ARRAY_FIELD no_insert_field

/* Inserts to connector tables happen elsewhere */
#define insert_MANY_TO_MANY_REL    no_insert_field
#define insert_BROKEN_TO_MANY_REL  no_insert_field

#define X(type, name) [type] = insert_##type,
#define Y(type, name) X(type, name)

static int (*field_inserters[])(struct restore *) = {
#include "field_types.c"
};

#undef X
#undef Y

static int finalize_insert(struct restore *data)
{
	if (sb_string(&data->stmt_buf, &data->stmt_size,
		      &data->stmt_filled, ");"))
		return -1;

	data->current_table->all_rows++;
	if (mysql_real_query(data->mysql, data->stmt_buf, data->stmt_filled)) {
		data->errors_count++;
		if (!data->current_table->insertion_errors++) {
			fprintf(data->raport_stream,
				"Nie udalo sie wstawic rekordu do bazy:\n"
				"Blad %u (%s): %s\n"
				"Zapytanie:\n"
				"%s\n",
				mysql_errno(data->mysql),
				mysql_sqlstate(data->mysql),
				mysql_error(data->mysql),
				data->stmt_buf);
		}
	} else {
		data->current_table->inserted_rows++;
	}

	return 0;
}

static void endElement_callback(void *user_data, const xmlChar *name)
{
	struct restore *data = user_data;
	struct field *field = data->current_field;

	if (data->fatal_error)
		return;

	switch (data->nesting--) {
	case 3:
		break;
	case 2:
		if (data->pass == PASS_2 &&
		    !data->current_table->creation_error &&
		    finalize_insert(data))
			goto fail;
	default:
		return;
	}

	switch (data->pass) {
	case PASS_1:
		if (!field)
			goto out;

		if (is_text_type(field->type) &&
		    field->spec_data.max_length < data->characters_count)
			field->spec_data.max_length = data->characters_count;

		if (field->type == ARRAY_FIELD &&
		    strchr(data->characters_buf, '"'))
			field->spec_data.array_has_data = true;

		break;
	case PASS_2:
		if (!field)
			goto fail;

		if (field_inserters[field->type](data))
			goto fail;
	}

	if (!data->creating_table)
		data->current_field = field->next;

out:
	return;

fail:
	data->fatal_error = true;
}

static void characters_callback(void *user_data, const xmlChar *characters,
				int len)
{
	struct restore *data = user_data;

	if (data->fatal_error)
		return;

	/* Should not happen, but... */
	if (!data->current_field) {
		if (data->pass == PASS_1)
			fprintf(data->raport_stream,
				"Znaki poza tagiem 'field': '%.*s'\n",
				len, characters);
		return;
	}

	switch (data->pass) {
	case PASS_1:
		if (data->current_field->type != ARRAY_FIELD) {
			data->characters_count += len;
			break;
		}
	case PASS_2:
		if (sb_bytes(&data->characters_buf, &data->characters_size,
			     &data->characters_count, characters, len))
			data->fatal_error = true;
	}
}

static void error_callback(void *user_data, const char *msg, ...)
{
	struct restore *data = user_data;
	va_list ap;
	int c;

	if (data->fatal_error)
		return;

	fprintf(data->raport_stream, "Blad xml: ");
	va_start(ap, msg);
	vfprintf(data->raport_stream, msg, ap);
	va_end(ap);
	if (!data->errors_count++) {
		fprintf(stderr, "Blad syntaktyczny xml, kontynuowac? y/N: ");
		fflush(stderr);
		c = getchar();
		if (c != 'y' && c != 'Y')
			data->fatal_error = true;
	}
}

static int clear_database(struct restore *data, const char *dbname)
{
	int res = -1;
	char *stmt_buf = NULL;
	size_t buf_len = 0, buf_filled = 0;
	struct sb_mysql_arg sb_arg;
	MYSQL_RES *query_res = NULL;
	size_t i;
	my_ulonglong rows;
	MYSQL_ROW *rows_array = NULL;

	sb_arg = (struct sb_mysql_arg) {data->mysql, dbname};
	if (sb_sprintf(&stmt_buf, &buf_len, &buf_filled,
		       "SELECT table_name "
		       "FROM information_schema.tables "
		       "WHERE table_schema = '%_';",
		       sb_mysql_escape, &sb_arg))
		goto fail;

	if (mysql_real_query(data->mysql, stmt_buf, buf_filled)) {
		fprintf(data->raport_stream,
			"Nie udalo sie pobrac nazw istniejacych tabel:\n"
			"Blad %u (%s): %s\n"
			"Zapytanie:\n"
			"%s\n",
			mysql_errno(data->mysql),
			mysql_sqlstate(data->mysql),
			mysql_error(data->mysql), stmt_buf);
		goto fail;
	}

	query_res = mysql_store_result(data->mysql);
	if (!query_res)
		goto fail;

	rows = mysql_num_rows(query_res);

	rows_array = malloc(sizeof(MYSQL_ROW) * rows);
	if (!rows_array)
		goto fail;

	for (i = 0; i < rows; i++) {
		rows_array[i] = mysql_fetch_row(query_res);
		if (!rows_array[i])
			goto fail;
	}

	for (i = 0; i < rows; i++) {
		printf("Usuwanie tabeli `%s`.\n", rows_array[i][0]);

		buf_filled = 0;

		/* Assume fetched table names are not malicious */
		if (sb_sprintf(&stmt_buf, &buf_len, &buf_filled,
			       "DROP TABLE IF EXISTS `%_`;",
			       sb_name_escape, rows_array[i][0]))
			goto fail;

		if (mysql_real_query(data->mysql, stmt_buf, buf_filled)) {
			fprintf(data->raport_stream,
				"Nie udalo sie usunac instniejacej tabeli:\n"
				"Blad %u (%s): %s\n",
				mysql_errno(data->mysql),
				mysql_sqlstate(data->mysql),
				mysql_error(data->mysql));
			goto fail;
		}
	}

	putchar('\n');
	res = 0;

fail:
	free(rows_array);
	if (query_res)
		mysql_free_result(query_res);
	free(stmt_buf);
	return res;
}

static int sb_field_name(char **stmt_buf, size_t *buf_len,
			 size_t *buf_filled, struct field *field)
{
	if (sb_sprintf(stmt_buf, buf_len, buf_filled,
		       ",\n"
		       "`%_` ",
		       sb_name_escape, field->name))
		return -1;

	return 0;
}

#define SIMPLE_FIELD_DECLARATOR(type, sql_name)				\
	static int sb_##type(char **stmt_buf, size_t *buf_len,		\
			     size_t *buf_filled, struct field *field)	\
	{								\
		if (sb_field_name(stmt_buf, buf_len,			\
				  buf_filled, field) ||			\
		    sb_string(stmt_buf, buf_len, buf_filled, sql_name)) \
			return -1;					\
									\
		return 0;						\
	}

SIMPLE_FIELD_DECLARATOR(TEXT_FIELD,         "TEXT")
SIMPLE_FIELD_DECLARATOR(INT_FIELD,          "INT")
SIMPLE_FIELD_DECLARATOR(SMALL_INT_FIELD,    "SMALLINT")
SIMPLE_FIELD_DECLARATOR(POSITIVE_INT_FIELD, "INT UNSIGNED")
SIMPLE_FIELD_DECLARATOR(BIG_INT_FIELD,      "BIGINT")
SIMPLE_FIELD_DECLARATOR(DECIMAL_FIELD,      "DECIMAL")
SIMPLE_FIELD_DECLARATOR(BOOL_FIELD,         "BOOL")
SIMPLE_FIELD_DECLARATOR(TIME_FIELD,         "TIME")
SIMPLE_FIELD_DECLARATOR(DATETIME_FIELD,     "DATETIME")
SIMPLE_FIELD_DECLARATOR(DATE_FIELD,         "DATE")
SIMPLE_FIELD_DECLARATOR(JSON_FIELD,         "TEXT")
/* We do foreign key constraints later, now we just create an int column */
SIMPLE_FIELD_DECLARATOR(ONE_TO_ONE_REL,     "INT")
SIMPLE_FIELD_DECLARATOR(MANY_TO_ONE_REL,    "INT")
SIMPLE_FIELD_DECLARATOR(BROKEN_TO_ONE_REL,  "INT")
SIMPLE_FIELD_DECLARATOR(UNKNOWN_FIELD,      "TEXT")

static int sb_CHAR_FIELD(char **stmt_buf, size_t *buf_len,
			 size_t *buf_filled, struct field *field)
{
	if (sb_field_name(stmt_buf, buf_len, buf_filled, field) ||
	    sb_sprintf(stmt_buf, buf_len, buf_filled, "VARCHAR(%u)",
		       (unsigned) field->spec_data.max_length))
		return -1;

	return 0;
}

#define sb_FILE_FIELD sb_CHAR_FIELD

static int no_sb_field(char **stmt_buf, size_t *buf_len,
		       size_t *buf_filled, struct field *field)
{
	return 0;
}

/* Deliberately omitted */
#define sb_EMPTY_ARRAY_FIELD no_sb_field

/* Realized in terms of separate tables */
#define sb_ARRAY_FIELD         no_sb_field
#define sb_MANY_TO_MANY_REL    no_sb_field
#define sb_BROKEN_TO_MANY_REL  no_sb_field

#define X(type, name) [type] = sb_##type,
#define Y(type, name) X(type, name)

static int (*field_declarators[])(char**, size_t*, size_t*, struct field*) = {
#include "field_types.c"
};

#undef X
#undef Y

static void create_mysql_table(const void *key, void *val, void *data_)
{
	bool fatal_error = true;
	struct table *table = val;
	struct field *field;
	struct restore *data = data_;
	char *stmt_buf = NULL;
	size_t buf_len = 0, buf_filled = 0;

	if (data->fatal_error)
		return;

	printf("Tworzenie tabeli `%s`.\n", table->name);

	if (sb_sprintf(&stmt_buf, &buf_len, &buf_filled,
		       "CREATE TABLE `%_` (\n"
		       "ID INT PRIMARY KEY",
		       sb_name_escape, table->name))
		goto fail;

	for (field = table->fields; field; field = field->next) {
		if (field_declarators[field->type](&stmt_buf, &buf_len,
						   &buf_filled, field))
			goto fail;
	}

	if (sb_string(&stmt_buf, &buf_len, &buf_filled, ");"))
		goto fail;

	if (mysql_real_query(data->mysql, stmt_buf, buf_filled)) {
		data->errors_count++;
		fprintf(data->raport_stream,
			"Nie udalo sie utworzyc tabeli `%s`:\n"
			"Blad %u (%s): %s\n"
			"Zapytanie:\n"
			"%s\n",
			table->name,
			mysql_errno(data->mysql),
			mysql_sqlstate(data->mysql),
			mysql_error(data->mysql),
			stmt_buf);
		table->creation_error = true;
	}

	fatal_error = false;

fail:
	free(stmt_buf);
	if (fatal_error)
		data->fatal_error = true;
}

static int create_mysql_tables(struct restore *data)
{
	ht_map(&data->tables, data, create_mysql_table);
	if (data->fatal_error)
		return -1;
	putchar('\n');
	return 0;
}

static void check_table_relations_correctness(const void *key, void *val,
					      void *data_)
{
	struct restore *data = data_;
	struct table *table = val, *target_table;
	struct field *field;

	for (field = table->fields; field; field = field->next) {
		if (field->type == ARRAY_FIELD &&
		    !field->spec_data.array_has_data) {
			fprintf(data->raport_stream,
				"Pole `%s` typu ARRAY tabeli `%s` nie zawiera danych, bedzie ono pominiete w odtworzonej bazie.\n",
				field->name, table->name);
			field->type = EMPTY_ARRAY_FIELD;
		}

		if (!is_rel_type(field->type))
			continue;

		target_table = NULL;

		/*
		 * I wrote that hashtable. I can assume certain ht api functions
		 * are re-entrant... Can I?
		 */
		if (!ht_get(&data->tables, field->spec_data.target_table,
			    NULL, (void**) &target_table) &&
		    !target_table->creation_error)
			continue;

		fprintf(data->raport_stream,
			"Relacja %s z tabeli `%s` (pole `%s`) do nie%s tabeli `%s`\n",
			field_enum_names[field->type],
			table->name, field->name,
			target_table ? "dodanej" : "istniejacej",
			field->spec_data.target_table);

		field->type = field->type == MANY_TO_MANY_REL ?
			BROKEN_TO_MANY_REL : BROKEN_TO_ONE_REL;
	}
}

static void check_tables_relations(struct restore *data)
{
	/* It's a bit of a cheat - assuming I can call ht_get() while mapping */
	ht_map(&data->tables, data, check_table_relations_correctness);
	fputc('\n', data->raport_stream);
}

static void fprint_field(FILE *os, const struct field *field)
{
	fprintf(os, "   `%s` %s", field->name, field_enum_names[field->type]);

	if (is_rel_type(field->type))
		fprintf(os, " to `%s`", field->spec_data.target_table);

	if (is_text_type(field->type)) {
		fprintf(os, " max %lu",
			(unsigned long) field->spec_data.max_length);
	}

	fputc('\n', os);
}

static void fprint_table(FILE *os, const struct table *table)
{
	struct field *field;

	fprintf(os, "Tabela `%s`\n", table->name);
	for (field = table->fields; field; field = field->next)
		fprint_field(os, field);

	putc('\n', os);
}

static void fprint_table_entry(const void *key, void *val, void *os)
{
	fprint_table(os, val);
}

static void fprint_all_tables(FILE *os, hashtable_t *tables)
{
	ht_map(tables, os, fprint_table_entry);
}

static int add_fk_constraint(struct restore *data, struct table *table,
			     struct field *field)
{
	int res = -1;
	char *stmt_buf = NULL;
	size_t buf_len = 0, buf_filled = 0;

	printf("Nakladanie ograniczenia na klucz obcy `%s` w tabeli `%s`.\n",
	       field->name, table->name);

	if (sb_sprintf(&stmt_buf, &buf_len, &buf_filled,
		       "ALTER TABLE `%_`\n"
		       "ADD CONSTRAINT `%__%__FK` FOREIGN KEY (`%_`)\n"
		       "REFERENCES `%_`(id);",
		       sb_name_escape, table->name, sb_name_escape, table->name,
		       sb_name_escape, field->name, sb_name_escape, field->name,
		       sb_name_escape, field->spec_data.target_table))
		goto out;

	if (mysql_real_query(data->mysql, stmt_buf, buf_filled)) {
		data->errors_count++;
		fprintf(data->raport_stream,
			"Nie udalo sie dodac ograniczenia klucza obcego na kolumne `%s` tabeli `%s`:\n"
			"Blad %u (%s): %s\n",
			field->name, table->name,
			mysql_errno(data->mysql),
			mysql_sqlstate(data->mysql),
			mysql_error(data->mysql));
	}

	res = 0;

out:
	free(stmt_buf);
	return res;
}

static int sb_maybe_references(char **buf, size_t *buf_len,
			       size_t *buf_filled, void *table_name)
{
	if (!table_name)
		return 0;

	return sb_sprintf(buf, buf_len, buf_filled,
			  " REFERENCES `%_`(id)", sb_name_escape, table_name);
}

static int create_mysql_mtm_table(struct restore *data, struct table *table,
				  struct field *field)
{
	int res = -1;
	char *stmt_buf = NULL;
	size_t buf_len = 0, buf_filled = 0;
	char *tab1 = table->name, *tab2 = field->spec_data.target_table;

	printf("Tworzenie tabeli lacznikowej `%s_mtm_%s`.\n", tab1, tab2);

	if (sb_sprintf(&stmt_buf, &buf_len, &buf_filled,
		       "CREATE TABLE `%__mtm_%_` (\n"
		       "`%__id` INT%_,\n"
		       "`%__%__id` INT%_,\n"
		       "PRIMARY KEY(`%__id`, `%__%__id`));",
		       sb_name_escape, tab1, sb_name_escape, tab2,
		       sb_name_escape, tab1,
		       sb_maybe_references,
		       table->creation_error ? NULL : tab1,
		       sb_name_escape, field->name, sb_name_escape, tab2,
		       sb_maybe_references,
		       field->type == BROKEN_TO_MANY_REL ? NULL : tab2,
		       sb_name_escape, tab1,
		       sb_name_escape, field->name, sb_name_escape, tab2))
		goto fail;

	if (mysql_real_query(data->mysql, stmt_buf, buf_filled)) {
		data->errors_count++;
		fprintf(data->raport_stream,
			"Nie udalo sie utworzyc tabeli lacznikowej `%s_mtm_%s`:\n"
			"Blad %u (%s): %s\n"
			"Zapytanie:\n"
			"%s\n",
			tab1, tab2,
			mysql_errno(data->mysql),
			mysql_sqlstate(data->mysql),
			mysql_error(data->mysql),
			stmt_buf);
		field->spec_data.target_table = NULL;
	}

	res = 0;

fail:
	free(stmt_buf);
	return res;
}

static int create_mysql_array(struct restore *data, struct table *table,
			      struct field *field)
{
	int res = -1;
	char *stmt_buf = NULL;
	size_t buf_len = 0, buf_filled = 0;

	printf("Tworzenie tabeli `%s_array_%s` do zrealizowania pola ARRAY.\n",
	       table->name, field->name);

	if (sb_sprintf(&stmt_buf, &buf_len, &buf_filled,
		       "CREATE TABLE `%__array_%_` (\n"
		       "id_of_element INT,\n"
		       "`%__id` INT%_,\n"
		       "element VARCHAR(255),\n"
		       "PRIMARY KEY(`%__id`, id_of_element));",
		       sb_name_escape, table->name, sb_name_escape, field->name,
		       sb_name_escape, table->name,
		       sb_maybe_references,
		       table->creation_error ? NULL : table->name,
		       sb_name_escape, table->name))
		goto fail;

	if (mysql_real_query(data->mysql, stmt_buf, buf_filled)) {
		data->errors_count++;
		fprintf(data->raport_stream,
			"Nie udalo sie utworzyc tabeli `%s_array%s` realizujacej pole typu ARRAY:\n"
			"Blad %u (%s): %s\n"
			"Zapytanie:\n"
			"%s\n",
			table->name, field->name,
			mysql_errno(data->mysql),
			mysql_sqlstate(data->mysql),
			mysql_error(data->mysql),
			stmt_buf);
		field->type = EMPTY_ARRAY_FIELD;
	}

	res = 0;

fail:
	free(stmt_buf);
	return res;
}

static void create_mysql_table_relations(const void *key, void *val,
					 void *data_)
{
	struct table *table = val;
	struct field *field;
	struct restore *data = data_;

	if (data->fatal_error)
		return;

	for (field = table->fields; field; field = field->next) {
		if ((field->type == MANY_TO_MANY_REL ||
		     field->type == BROKEN_TO_MANY_REL) &&
		    create_mysql_mtm_table(data, table, field))
			goto fail;

		if (field->type == ARRAY_FIELD &&
		    create_mysql_array(data, table, field))
			goto fail;

		if (table->creation_error)
			continue;

		if ((field->type == ONE_TO_ONE_REL ||
		     field->type == MANY_TO_ONE_REL) &&
		    add_fk_constraint(data, table, field))
			goto fail;
	}

	return;

fail:
	data->fatal_error = true;
}

static int complete_mysql_tables(struct restore *data)
{
	ht_map(&data->tables, data, create_mysql_table_relations);
	if (data->fatal_error)
		return -1;
	putchar('\n');
	return 0;
}

static void print_table_summary(const void *key, void *val, void *data_)
{
	struct table *table = val;
	struct restore *data = data_;

	if (!table->all_rows) {
		fprintf(data->raport_stream,
			"Nie wstawiono zadnych rekordow do tabeli `table->name`.\n");
		return;
	}

	fprintf(data->raport_stream,
		"Rekordy wstawione do tabeli `%s`: %ld/%ld\n",
		table->name, (long) table->inserted_rows,
		(long) table->all_rows);

	if (!table->insertion_errors)
		return;

	fprintf(data->raport_stream,
		"Bledy przy wypelnianiu tabeli `%s`: %ld\n",
		table->name, (long) table->insertion_errors);
}

static void print_entire_summary(struct restore *data)
{
	ht_map(&data->tables, data, print_table_summary);
	fputc('\n', data->raport_stream);
}

static inline void error_exit(const char *msg, ...)
{
	va_list ap;

	va_start(ap, msg);
	vfprintf(stderr, msg, ap);
	va_end(ap);
	fputc('\n', stderr);

	exit(-1);
}

const char foreign_checks_off[] = "SET FOREIGN_KEY_CHECKS = 0;";
const char foreign_checks_on[]  = "SET FOREIGN_KEY_CHECKS = 1;";
const char set_utf8[]           = "SET NAMES 'utf8';";

int main(int argc, char **argv)
{
	const char *xml_path, *db_host, *db_user, *db_password, *db_name,
		*raport_path = NULL;
	int db_port;
	xmlSAXHandler sax1, sax2;
	struct restore data;
	int i;

	if (argc < 7) {
		error_exit("Zbyt malo argumentów. Oczekiwane:\n"
			   "restore SCIEZKA_PLIKU_XML ADRES_BAZY PORT UZYTKOWNIK HASLO NAZWA_BAZY [SCIEZKA_PLIKU_RAPORTU]");
	}

	xml_path    = argv[1];
	db_host     = argv[2];
	db_port     = atoi(argv[3]);
	db_user     = argv[4];
	db_password = argv[5];
	db_name     = argv[6];

	if (argc >= 8)
		raport_path = argv[7];

	memset(&sax1, 0, sizeof(sax1));
	if (init_restore_data(&data, raport_path))
		error_exit("Blad inicjalizacji wewnetrznych struktur.");

	sax1.initialized = XML_SAX2_MAGIC;
	sax1.startElement = startElement_callback;
	sax1.endElement = endElement_callback;
	sax1.characters = characters_callback;

	sax2 = sax1;

	sax1.error = error_callback;

	data.pass = PASS_1;
	xmlSAXUserParseFile(&sax1, &data, xml_path);
	if (data.fatal_error || !data.tables.entries)
		error_exit("Nie udalo sie ustalic schematu bazy.");
	if (data.errors_count) {
		fprintf(data.raport_stream,
			"Byly bledy podczas czytania pliku xml (%ld).\n",
			(long) data.errors_count);
	}

	putc('\n', data.raport_stream);

	/* initialize connection handler */
	data.mysql = mysql_init(NULL);
	if (!data.mysql)
		error_exit("Blad inicializacji libmysql (prawdopodobnie brak pamieci).");

	/* connect to server */
	if (!mysql_real_connect(data.mysql,
				db_host, db_user, db_password, db_name, db_port,
				NULL, 0)) {
		fprintf(data.raport_stream,
			"Nie udalo sie polaczyc z baza.\n"
			"Blad %u (%s): %s\n",
			mysql_errno(data.mysql),
			mysql_sqlstate(data.mysql),
			mysql_error(data.mysql));
		mysql_close(data.mysql);
		return -1;
	}

	printf("Polaczono z baza\n\n");

	/* Re-enabling foreign checks later is not needed. */
	if (mysql_real_query(data.mysql, foreign_checks_off,
			     sizeof(foreign_checks_off) - 1)) {
		fprintf(data.raport_stream,
			"Nie udalo sie wylaczyc sprawdzania spojnosci relacji.\n"
			"Blad %u (%s): %s\n",
			mysql_errno(data.mysql),
			mysql_sqlstate(data.mysql),
			mysql_error(data.mysql));
		error_exit("Blad podczas wylaczania sprawdzania spojnosci relacji.");
	}

	/* Setting utf-8 for communication between database and the client. */
	if (mysql_real_query(data.mysql, set_utf8, sizeof(set_utf8) - 1)) {
		data.errors_count++;
		fprintf(data.raport_stream,
			"Nie udalo sie ustawic kodowania utf8.\n"
			"Blad %u (%s): %s\n",
			mysql_errno(data.mysql),
			mysql_sqlstate(data.mysql),
			mysql_error(data.mysql));
	}

	if (clear_database(&data, "nowabaze")) {
		error_exit("Blad podczas usuwania starej zawartosci bazy.");
	}

	if (create_mysql_tables(&data))
		error_exit("Blad podczas tworzenia tabel.");

	check_tables_relations(&data);
	fprint_all_tables(data.raport_stream, &data.tables);

	if (complete_mysql_tables(&data))
		error_exit("Blad podczas uzupelniania utworzonych tabel.");

	data.pass = 2;
	xmlSAXUserParseFile(&sax2, &data, xml_path);
	putchar('\n');
	fputc('\n', data.raport_stream);
	print_entire_summary(&data);
	if (data.fatal_error)
		error_exit("Fatalny blad podczas umieszczania danych w bazie.");

#define OS(n) ((n) == 0 ? data.raport_stream : stdout)
	for (i = data.raport_stream == stdout ? 0 : 1; i >= 0; i--) {
		fprintf(OS(i), "Operacja zakonczona");
		if (data.errors_count) {
			fprintf(OS(i), "; bledow lacznie: %ld\n",
				(long) data.errors_count);
		} else {
			fprintf(OS(i), " bez bledow.\n");
		}
	}

	mysql_close(data.mysql);

	destroy_restore_data(&data);

	return 0;
}