/*
 * Odissey.
 *
 * Advanced PostgreSQL connection pooler.
*/

#include <stdlib.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <ctype.h>
#include <assert.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <machinarium.h>

#include "sources/macro.h"
#include "sources/version.h"
#include "sources/list.h"
#include "sources/pid.h"
#include "sources/id.h"
#include "sources/syslog.h"
#include "sources/log.h"
#include "sources/daemon.h"
#include "sources/scheme.h"
#include "sources/scheme_mgr.h"
#include "sources/parser.h"
#include "sources/config.h"

enum
{
	OD_LYES,
	OD_LNO,
	OD_LDAEMONIZE,
	OD_LLOG_DEBUG,
	OD_LLOG_CONFIG,
	OD_LLOG_SESSION,
	OD_LLOG_FILE,
	OD_LLOG_STATISTICS,
	OD_LPID_FILE,
	OD_LSYSLOG,
	OD_LSYSLOG_IDENT,
	OD_LSYSLOG_FACILITY,
	OD_LLISTEN,
	OD_LHOST,
	OD_LPORT,
	OD_LBACKLOG,
	OD_LNODELAY,
	OD_LKEEPALIVE,
	OD_LREADAHEAD,
	OD_LPIPELINING,
	OD_LWORKERS,
	OD_LCLIENT_MAX,
	OD_LTLS,
	OD_LTLS_CA_FILE,
	OD_LTLS_KEY_FILE,
	OD_LTLS_CERT_FILE,
	OD_LTLS_PROTOCOLS,
	OD_LSTORAGE,
	OD_LTYPE,
	OD_LDEFAULT,
	OD_LDATABASE,
	OD_LUSER,
	OD_LPASSWORD,
	OD_LPOOL,
	OD_LPOOL_SIZE,
	OD_LPOOL_TIMEOUT,
	OD_LPOOL_TTL,
	OD_LPOOL_CANCEL,
	OD_LPOOL_DISCARD,
	OD_LPOOL_ROLLBACK,
	OD_LSTORAGE_DB,
	OD_LSTORAGE_USER,
	OD_LSTORAGE_PASSWORD,
	OD_LAUTHENTICATION
};

typedef struct
{
	od_parser_t  parser;
	od_scheme_t *scheme;
	od_log_t    *log;
	char        *config_file;
	char        *data;
	int          data_size;
	int          version;
} od_config_t;

#define od_keyword(name, token) { token, name, sizeof(name) - 1 }

static od_keyword_t od_config_keywords[] =
{
	/* main */
	od_keyword("yes",              OD_LYES),
	od_keyword("no",               OD_LNO),
	od_keyword("daemonize",        OD_LDAEMONIZE),
	od_keyword("log_debug",        OD_LLOG_DEBUG),
	od_keyword("log_config",       OD_LLOG_CONFIG),
	od_keyword("log_session",      OD_LLOG_SESSION),
	od_keyword("log_file",         OD_LLOG_FILE),
	od_keyword("log_statistics",   OD_LLOG_STATISTICS),
	od_keyword("pid_file",         OD_LPID_FILE),
	od_keyword("syslog",           OD_LSYSLOG),
	od_keyword("syslog_ident",     OD_LSYSLOG_IDENT),
	od_keyword("syslog_facility",  OD_LSYSLOG_FACILITY),
	/* listen */
	od_keyword("listen",           OD_LLISTEN),
	od_keyword("host",             OD_LHOST),
	od_keyword("port",             OD_LPORT),
	od_keyword("backlog",          OD_LBACKLOG),
	od_keyword("nodelay",          OD_LNODELAY),
	od_keyword("keepalive",        OD_LKEEPALIVE),
	od_keyword("readahead",        OD_LREADAHEAD),
	od_keyword("pipelining",       OD_LPIPELINING),
	od_keyword("workers",          OD_LWORKERS),
	od_keyword("client_max",       OD_LCLIENT_MAX),
	od_keyword("tls",              OD_LTLS),
	od_keyword("tls_ca_file",      OD_LTLS_CA_FILE),
	od_keyword("tls_key_file",     OD_LTLS_KEY_FILE),
	od_keyword("tls_cert_file",    OD_LTLS_CERT_FILE),
	od_keyword("tls_protocols",    OD_LTLS_PROTOCOLS),
	/* storage */
	od_keyword("storage",          OD_LSTORAGE),
	od_keyword("type",             OD_LTYPE),
	od_keyword("default",          OD_LDEFAULT),
	/* database */
	od_keyword("database",         OD_LDATABASE),
	od_keyword("user",             OD_LUSER),
	od_keyword("password",         OD_LPASSWORD),
	od_keyword("pool",             OD_LPOOL),
	od_keyword("pool_size",        OD_LPOOL_SIZE),
	od_keyword("pool_timeout",     OD_LPOOL_TIMEOUT),
	od_keyword("pool_ttl",         OD_LPOOL_TTL),
	od_keyword("pool_cancel",      OD_LPOOL_CANCEL),
	od_keyword("pool_discard",     OD_LPOOL_DISCARD),
	od_keyword("pool_rollback",    OD_LPOOL_ROLLBACK),
	od_keyword("storage_db",       OD_LSTORAGE_DB),
	od_keyword("storage_user",     OD_LSTORAGE_USER),
	od_keyword("storage_password", OD_LSTORAGE_PASSWORD),
	od_keyword("authentication",   OD_LAUTHENTICATION),
	{ 0, 0, 0 }
};

static int
od_config_open(od_config_t *config, char *config_file)
{
	config->config_file = config_file;
	/* read file */
	struct stat st;
	int rc = lstat(config_file, &st);
	if (rc == -1) {
		od_error(config->log, "config", "failed to open config file '%s'",
		         config_file);
		return -1;
	}
	char *config_buf = malloc(st.st_size);
	if (config_buf == NULL) {
		od_error(config->log, "config", "memory allocation error");
		return -1;
	}
	FILE *file = fopen(config_file, "r");
	if (file == NULL) {
		free(config_buf);
		od_error(config->log, "config", "failed to open config file '%s'",
		         config_file);
		return -1;
	}
	rc = fread(config_buf, st.st_size, 1, file);
	fclose(file);
	if (rc != 1) {
		free(config_buf);
		od_error(config->log, "config", "failed to open config file '%s'",
		         config_file);
		return -1;
	}
	config->data = config_buf;
	config->data_size = st.st_size;
	od_parser_init(&config->parser, config->data, config->data_size);
	return 0;
}

static void
od_config_close(od_config_t *config)
{
	free(config->data);
}

static void
od_config_error(od_config_t *config, od_token_t *token, char *fmt, ...)
{
	char msg[256];
	va_list args;
	va_start(args, fmt);
	vsnprintf(msg, sizeof(msg), fmt, args);
	va_end(args);
	int line = config->parser.line;
	if (token)
		line = token->line;
	od_error(config->log, "config", "%s:%d %s", config->config_file,
	         line, msg);
}

static bool
od_config_next_is(od_config_t *config, int id)
{
	od_token_t token;
	int rc;
	rc = od_parser_next(&config->parser, &token);
	od_parser_push(&config->parser, &token);
	if (rc != id)
		return false;
	return true;
}

static bool
od_config_next_keyword(od_config_t *config, od_keyword_t *keyword)
{
	od_token_t token;
	int rc;
	rc = od_parser_next(&config->parser, &token);
	if (rc != OD_PARSER_KEYWORD)
		goto error;
	od_keyword_t *match;
	match = od_keyword_match(od_config_keywords, &token);
	if (keyword == NULL)
		goto error;
	if (keyword != match)
		goto error;
	return true;
error:
	od_parser_push(&config->parser, &token);
	od_config_error(config, &token, "expected '%s'", keyword->name);
	return false;
}

static bool
od_config_next_symbol(od_config_t *config, char symbol)
{
	od_token_t token;
	int rc;
	rc = od_parser_next(&config->parser, &token);
	if (rc != OD_PARSER_SYMBOL)
		goto error;
	if (token.value.num != (uint64_t)symbol)
		goto error;
	return true;
error:
	od_parser_push(&config->parser, &token);
	od_config_error(config, &token, "expected '%c'", symbol);
	return false;
}

static bool
od_config_next_string(od_config_t *config, char **value)
{
	od_token_t token;
	int rc;
	rc = od_parser_next(&config->parser, &token);
	if (rc != OD_PARSER_STRING) {
		od_parser_push(&config->parser, &token);
		od_config_error(config, &token, "expected 'string'");
		return false;
	}
	char *copy = malloc(token.value.string.size + 1);
	if (copy == NULL) {
		od_parser_push(&config->parser, &token);
		od_config_error(config, &token, "memory allocation error");
		return false;
	}
	memcpy(copy, token.value.string.pointer, token.value.string.size);
	copy[token.value.string.size] = 0;
	if (*value)
		free(*value);
	*value = copy;
	return true;
}

static bool
od_config_next_number(od_config_t *config, int *number)
{
	od_token_t token;
	int rc;
	rc = od_parser_next(&config->parser, &token);
	if (rc != OD_PARSER_NUM) {
		od_parser_push(&config->parser, &token);
		od_config_error(config, &token, "expected 'number'");
		return false;
	}
	/* uint64 to int conversion */
	*number = token.value.num;
	return true;
}

static bool
od_config_next_yes_no(od_config_t *config, int *value)
{
	od_token_t token;
	int rc;
	rc = od_parser_next(&config->parser, &token);
	if (rc != OD_PARSER_KEYWORD)
		goto error;
	od_keyword_t *keyword;
	keyword = od_keyword_match(od_config_keywords, &token);
	if (keyword == NULL)
		goto error;
	switch (keyword->id) {
	case OD_LYES:
		*value = 1;
		break;
	case OD_LNO:
		*value = 0;
		break;
	default:
		goto error;
	}
	return true;
error:
	od_parser_push(&config->parser, &token);
	od_config_error(config, &token, "expected 'yes/no'");
	return false;
}

static int
od_config_parse_listen(od_config_t *config)
{
	od_scheme_t *scheme = config->scheme;

	/* { */
	if (! od_config_next_symbol(config, '{'))
		return -1;

	for (;;)
	{
		od_token_t token;
		int rc;
		rc = od_parser_next(&config->parser, &token);
		switch (rc) {
		case OD_PARSER_KEYWORD:
			break;
		case OD_PARSER_EOF:
			od_config_error(config, &token, "unexpected end of config file");
			return -1;
		case OD_PARSER_SYMBOL:
			/* } */
			if (token.value.num == '}')
				return 0;
			/* fall through */
		default:
			od_config_error(config, &token, "incorrect or unexpected parameter");
			return -1;
		}
		od_keyword_t *keyword;
		keyword = od_keyword_match(od_config_keywords, &token);
		if (keyword == NULL) {
			od_config_error(config, &token, "unknown parameter");
			return -1;
		}
		switch (keyword->id) {
		/* host */
		case OD_LHOST:
			if (! od_config_next_string(config, &scheme->host))
				return -1;
			continue;
		/* port */
		case OD_LPORT:
			if (! od_config_next_number(config, &scheme->port))
				return -1;
			continue;
		/* backlog */
		case OD_LBACKLOG:
			if (! od_config_next_number(config, &scheme->backlog))
				return -1;
			continue;
		/* nodelay */
		case OD_LNODELAY:
			if (! od_config_next_yes_no(config, &scheme->nodelay))
				return -1;
			continue;
		/* keepalive */
		case OD_LKEEPALIVE:
			if (! od_config_next_number(config, &scheme->keepalive))
				return -1;
			continue;
		/* tls */
		case OD_LTLS:
			if (! od_config_next_string(config, &scheme->tls))
				return -1;
			continue;
		/* tls_ca_file */
		case OD_LTLS_CA_FILE:
			if (! od_config_next_string(config, &scheme->tls_ca_file))
				return -1;
			continue;
		/* tls_key_file */
		case OD_LTLS_KEY_FILE:
			if (! od_config_next_string(config, &scheme->tls_key_file))
				return -1;
			continue;
		/* tls_cert_file */
		case OD_LTLS_CERT_FILE:
			if (! od_config_next_string(config, &scheme->tls_cert_file))
				return -1;
			continue;
		/* tls_protocols */
		case OD_LTLS_PROTOCOLS:
			if (! od_config_next_string(config, &scheme->tls_protocols))
				return -1;
			continue;
		default:
			od_config_error(config, &token, "unexpected parameter");
			return -1;
		}
	}
	/* unreach */
	return -1;
}

static int
od_config_parse_storage(od_config_t *config)
{
	od_schemestorage_t *storage;
	storage = od_schemestorage_add(config->scheme, config->version);
	if (storage == NULL)
		return -1;
	/* name */
	if (! od_config_next_string(config, &storage->name))
		return -1;
	/* { */
	if (! od_config_next_symbol(config, '{'))
		return -1;

	for (;;)
	{
		od_token_t token;
		int rc;
		rc = od_parser_next(&config->parser, &token);
		switch (rc) {
		case OD_PARSER_KEYWORD:
			break;
		case OD_PARSER_EOF:
			od_config_error(config, &token, "unexpected end of config file");
			return -1;
		case OD_PARSER_SYMBOL:
			/* } */
			if (token.value.num == '}')
				return 0;
			/* fall through */
		default:
			od_config_error(config, &token, "incorrect or unexpected parameter");
			return -1;
		}
		od_keyword_t *keyword;
		keyword = od_keyword_match(od_config_keywords, &token);
		if (keyword == NULL) {
			od_config_error(config, &token, "unknown parameter");
			return -1;
		}
		switch (keyword->id) {
		/* type */
		case OD_LTYPE:
			if (! od_config_next_string(config, &storage->type))
				return -1;
			continue;
		/* host */
		case OD_LHOST:
			if (! od_config_next_string(config, &storage->host))
				return -1;
			continue;
		/* port */
		case OD_LPORT:
			if (! od_config_next_number(config, &storage->port))
				return -1;
			continue;
		/* tls */
		case OD_LTLS:
			if (! od_config_next_string(config, &storage->tls))
				return -1;
			continue;
		/* tls_ca_file */
		case OD_LTLS_CA_FILE:
			if (! od_config_next_string(config, &storage->tls_ca_file))
				return -1;
			continue;
		/* tls_key_file */
		case OD_LTLS_KEY_FILE:
			if (! od_config_next_string(config, &storage->tls_key_file))
				return -1;
			continue;
		/* tls_cert_file */
		case OD_LTLS_CERT_FILE:
			if (! od_config_next_string(config, &storage->tls_cert_file))
				return -1;
			continue;
		/* tls_protocols */
		case OD_LTLS_PROTOCOLS:
			if (! od_config_next_string(config, &storage->tls_protocols))
				return -1;
			continue;
		default:
			od_config_error(config, &token, "unexpected parameter");
			return -1;
		}
	}
	/* unreach */
	return -1;
}

static int
od_config_parse_user(od_config_t *config, od_schemedb_t *db)
{
	od_schemeuser_t *user;
	user = od_schemeuser_add(db);
	if (user == NULL)
		return -1;

	/* name or default */
	if (od_config_next_is(config, OD_PARSER_STRING)) {
		if (! od_config_next_string(config, &user->user))
			return -1;
	} else {
		if (! od_config_next_keyword(config, &od_config_keywords[OD_LDEFAULT]))
			return -1;
		user->is_default = 1;
		user->user = strdup("default");
		if (user->user == NULL)
			return -1;
	}
	user->db = db;
	user->user_len = strlen(user->user);

	/* { */
	if (! od_config_next_symbol(config, '{'))
		return -1;

	for (;;)
	{
		od_token_t token;
		int rc;
		rc = od_parser_next(&config->parser, &token);
		switch (rc) {
		case OD_PARSER_KEYWORD:
			break;
		case OD_PARSER_EOF:
			od_config_error(config, &token, "unexpected end of config file");
			return -1;
		case OD_PARSER_SYMBOL:
			/* } */
			if (token.value.num == '}')
				return 0;
			/* fall through */
		default:
			od_config_error(config, &token, "incorrect or unexpected parameter");
			return -1;
		}
		od_keyword_t *keyword;
		keyword = od_keyword_match(od_config_keywords, &token);
		if (keyword == NULL) {
			od_config_error(config, &token, "unknown parameter");
			return -1;
		}
		switch (keyword->id) {
		/* authentication */
		case OD_LAUTHENTICATION:
			if (! od_config_next_string(config, &user->auth))
				return -1;
			break;
		/* password */
		case OD_LPASSWORD:
			if (! od_config_next_string(config, &user->user_password))
				return -1;
			user->user_password_len = strlen(user->user_password);
			continue;
		/* storage */
		case OD_LSTORAGE:
			if (! od_config_next_string(config, &user->storage_name))
				return -1;
			continue;
		/* client_max */
		case OD_LCLIENT_MAX:
			if (! od_config_next_number(config, &user->client_max))
				return -1;
			user->client_max_set = 1;
			continue;
		/* pool */
		case OD_LPOOL:
			if (! od_config_next_string(config, &user->pool_sz))
				return -1;
			continue;
		/* pool_size */
		case OD_LPOOL_SIZE:
			if (! od_config_next_number(config, &user->pool_size))
				return -1;
			continue;
		/* pool_timeout */
		case OD_LPOOL_TIMEOUT:
			if (! od_config_next_number(config, &user->pool_timeout))
				return -1;
			continue;
		/* pool_ttl */
		case OD_LPOOL_TTL:
			if (! od_config_next_number(config, &user->pool_ttl))
				return -1;
			continue;
		/* storage_database */
		case OD_LSTORAGE_DB:
			if (! od_config_next_string(config, &user->storage_db))
				return -1;
			continue;
		/* storage_user */
		case OD_LSTORAGE_USER:
			if (! od_config_next_string(config, &user->storage_user))
				return -1;
			user->storage_user_len = strlen(user->storage_user);
			continue;
		/* storage_password */
		case OD_LSTORAGE_PASSWORD:
			if (! od_config_next_string(config, &user->storage_password))
				return -1;
			user->storage_password_len = strlen(user->storage_password);
			continue;
		/* pool_cancel */
		case OD_LPOOL_CANCEL:
			if (! od_config_next_yes_no(config, &user->pool_cancel))
				return -1;
			continue;
		/* pool_discard */
		case OD_LPOOL_DISCARD:
			if (! od_config_next_yes_no(config, &user->pool_discard))
				return -1;
			continue;
		/* pool_rollback */
		case OD_LPOOL_ROLLBACK:
			if (! od_config_next_yes_no(config, &user->pool_rollback))
				return -1;
			continue;
		default:
			od_config_error(config, &token, "unexpected parameter");
			return -1;
		}
	}
	/* unreach */
	return -1;
}

static int
od_config_parse_database(od_config_t *config)
{
	od_schemedb_t *db;
	db = od_schemedb_add(config->scheme, config->version);
	if (db == NULL)
		return -1;

	/* name or default */
	if (od_config_next_is(config, OD_PARSER_STRING)) {
		if (! od_config_next_string(config, &db->name))
			return -1;
	} else {
		if (! od_config_next_keyword(config, &od_config_keywords[OD_LDEFAULT]))
			return -1;
		db->is_default = 1;
		db->name = strdup("default");
		if (db->name == NULL)
			return -1;
	}

	/* { */
	if (! od_config_next_symbol(config, '{'))
		return -1;

	for (;;)
	{
		od_token_t token;
		int rc;
		rc = od_parser_next(&config->parser, &token);
		switch (rc) {
		case OD_PARSER_KEYWORD:
			break;
		case OD_PARSER_EOF:
			od_config_error(config, &token, "unexpected end of config file");
			return -1;
		case OD_PARSER_SYMBOL:
			/* } */
			if (token.value.num == '}')
				return 0;
			/* fall through */
		default:
			od_config_error(config, &token, "incorrect or unexpected parameter");
			return -1;
		}
		od_keyword_t *keyword;
		keyword = od_keyword_match(od_config_keywords, &token);
		if (keyword == NULL) {
			od_config_error(config, &token, "unknown parameter");
			return -1;
		}
		switch (keyword->id) {
		/* user */
		case OD_LUSER:
			rc = od_config_parse_user(config, db);
			if (rc == -1)
				return -1;
			continue;
		default:
			od_config_error(config, &token, "unexpected parameter");
			return -1;
		}
	}
	/* unreach */
	return -1;
}

static int
od_config_parse(od_config_t *config)
{
	od_scheme_t *scheme = config->scheme;
	for (;;)
	{
		od_token_t token;
		int rc;
		rc = od_parser_next(&config->parser, &token);
		switch (rc) {
		case OD_PARSER_EOF:
			return 0;
		case OD_PARSER_KEYWORD:
			break;
		default:
			od_config_error(config, &token, "incorrect or unexpected parameter");
			return -1;
		}
		od_keyword_t *keyword;
		keyword = od_keyword_match(od_config_keywords, &token);
		if (keyword == NULL) {
			od_config_error(config, &token, "unknown parameter");
			return -1;
		}
		switch (keyword->id) {
		/* daemonize */
		case OD_LDAEMONIZE:
			if (! od_config_next_yes_no(config, &scheme->daemonize))
				return -1;
			continue;
		/* log_debug */
		case OD_LLOG_DEBUG:
			if (! od_config_next_yes_no(config, &scheme->log_debug))
				return -1;
			continue;
		/* log_config */
		case OD_LLOG_CONFIG:
			if (! od_config_next_yes_no(config, &scheme->log_config))
				return -1;
			continue;
		/* log_session */
		case OD_LLOG_SESSION:
			if (! od_config_next_yes_no(config, &scheme->log_session))
				return -1;
			continue;
		/* log_statistics */
		case OD_LLOG_STATISTICS:
			if (! od_config_next_number(config, &scheme->log_statistics))
				return -1;
			continue;
		/* log_file */
		case OD_LLOG_FILE:
			if (! od_config_next_string(config, &scheme->log_file))
				return -1;
			continue;
		/* pid_file */
		case OD_LPID_FILE:
			if (! od_config_next_string(config, &scheme->pid_file))
				return -1;
			continue;
		/* syslog */
		case OD_LSYSLOG:
			if (! od_config_next_yes_no(config, &scheme->syslog))
				return -1;
			continue;
		/* syslog_ident */
		case OD_LSYSLOG_IDENT:
			if (! od_config_next_string(config, &scheme->syslog_ident))
				return -1;
			continue;
		/* syslog_facility */
		case OD_LSYSLOG_FACILITY:
			if (! od_config_next_string(config, &scheme->syslog_facility))
				return -1;
			continue;
		/* client_max */
		case OD_LCLIENT_MAX:
			if (! od_config_next_number(config, &scheme->client_max))
				return -1;
			scheme->client_max_set = 1;
			continue;
		/* readahead */
		case OD_LREADAHEAD:
			if (! od_config_next_number(config, &scheme->readahead))
				return -1;
			continue;
		/* pipelining */
		case OD_LPIPELINING:
			if (! od_config_next_number(config, &scheme->server_pipelining))
				return -1;
			continue;
		/* workers */
		case OD_LWORKERS:
			if (! od_config_next_number(config, &scheme->workers))
				return -1;
			continue;
		/* listen */
		case OD_LLISTEN:
			rc = od_config_parse_listen(config);
			if (rc == -1)
				return -1;
			continue;
		/* storage */
		case OD_LSTORAGE:
			rc = od_config_parse_storage(config);
			if (rc == -1)
				return -1;
			continue;
		/* database */
		case OD_LDATABASE:
			rc = od_config_parse_database(config);
			if (rc == -1)
				return -1;
			continue;
		default:
			od_config_error(config, &token, "unexpected parameter");
			return -1;
		}
	}
	/* unreach */
	return -1;
}

int od_config_load(od_schememgr_t *mgr, od_scheme_t *scheme, od_log_t *log, char *config_file)
{
	od_config_t config;
	memset(&config, 0, sizeof(config));
	config.log = log;
	config.scheme = scheme;
	config.version = od_schememgr_version_next(mgr);
	int rc;
	rc = od_config_open(&config, config_file);
	if (rc == -1)
		return -1;
	rc = od_config_parse(&config);
	od_config_close(&config);
	return rc;
}