#ifndef DBSERVER_H
#define DBSERVER_H
#include <csse2310a3.h>
#include <csse2310a4.h>
#include <ctype.h>
#include <netdb.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stringstore.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#define PORT_MIN 1024
#define PORT_MAX 65535

#define MAX_BACKLOG 10

#define UNAVALIABLE_RESPONSE \
    "HTTP/1.1 503 Service Unavaliable\r\nContent-Length: 0\r\n\r\n"
#define OK_RESPONSE "HTTP/1.1 200 OK\r\nContent-Length: 0\r\n\r\n"
#define ISR_RESPONSE \
    "HTTP/1.1 500 Internal Server Error\r\nContent-Length: 0\r\n\r\n"

#define PROGRAM_USAGE "Usage: dbserver authfile connections [portnum]\n"

#define PUBLIC_PATH "/public/"
#define PRIVATE_PATH "/private/"

// Program exit codes
enum ExitCodes {
    EXIT_OK = 0,
    EXIT_ERR = 1,
    EXIT_FILE_ERR = 2,
    EXIT_PORT_ERR = 3
};

// Server Statistics
struct ServerStatistics {
    int currentConnections;
    int completedConnections;
    int authFails;
    int gets;
    int puts;
    int deletes;
    pthread_mutex_t connectionLock;
};

// Connection information needed for threads
struct ConnectionInfo {
    int fd;
    int connections;
    char *authKey;
    struct ConnectionThread *connectionThread;
    StringStore **stringStores;
};

// Information regarding a client request
struct RequestParams {
    char *method;
    char *path;
    char *key;
    char *value;
    char *authKey;
    HttpHeader **headers;
};

// The server statistic instance, global as needed to be called by SIGHUP
struct ServerStatistics *serverStats;

/* get_nth_char_position()
 * -----------------------
 * Get the character position of the nth occurrence of that character
 *
 * s: the string to search
 * c: the character to look for
 * n: the nth occurance to retrieve the position of
 *
 * Returns: the position of the nth ocurrance of the given character
 */
int get_nth_char_position(const char *s, int c, int n);

/* get_valid_number()
 * ------------------
 * Checks if a given number is an actual number, then returns it as an int
 *
 * rawNumber: the number to check and convert
 *
 * Returns: -1 if the number is not valid, the converted string if it is
 * valid
 */
int get_valid_number(char *rawNumber);

/* get_authkey_from_file()
 * -----------------------
 * Gets the first line from a file
 *
 * filePath: the path to the file
 *
 * Returns: NULL if the file does not exist or the first line does not
 * exist, the first line otherwise
 */
char *get_authkey_from_file(char *filePath);

/* get_address_info()
 * ------------------
 * Gets the required addrinfo for the given port
 *
 * port: the port to assign to
 *
 * Returns: the appropriate addrinfo
 */
struct addrinfo *get_address_info(int port);

/* open_socket()
 * -------------
 * Opens a socket for the given port holding the given connections
 *
 * port: the port to open a socket on
 * connections: the amount of connections to support
 *
 * Returns: -1 if failed to connect to socket, 0 if success
 */
int open_socket(int port);

/* serverstats_init()
 * -----------------------
 * Initializes the server statistics
 *
 * Returns: the newly initialised server stats
 */
void serverstats_init(void);

/* handle_listen()
 * ---------------
 * Opens a socket and deals with connections
 *
 * port: the port to open a socket on
 * connections: the amount of connections to support
 * authKey: the authorization key for the private db
 *
 * Returns: 3 if failed to connect to socket, 0 if success
 */
int handle_listen(int port, int connections, char *authKey);

/* process_response_get()
 * -----------------------
 * Gets the appropriate get response for the request from the client
 *
 * key: the key to get the value of from the db
 * stringStore: the db
 *
 * Returns: the appropriate response (200 with value or 404)
 */
char *process_response_get(char *key, StringStore *stringStore);

/* process_response_put()
 * -----------------------
 * Adds the appropriate value to the db and then gets the appropriate
 * response
 *
 * key: the key to update the value of in the db
 * value: the value to update the key with
 * stringStore: the db
 *
 * Returns: the appropiate response (200 or 500 if failed)
 */
char *process_response_put(char *key, char *value, StringStore *stringStore);

/* process_response_delete()
 * -----------------------
 * Deletes the given key from the db and returns the appropriate response
 *
 * key: the key to delete from the db
 * stringStore: the db
 *
 * Returns: the appropriate response (200 or 404)
 */
char *process_response_delete(char *key, StringStore *stringStore);

/* check_auth_key()
 * ----------------
 * Check the given authentication key with the given headers
 *
 * headers: the headers that may contain the authorization header
 * authKey: the auth key to check against the header
 *
 * Returns: 1 if the key matches, 0 otherwise
 */
int check_auth_key(HttpHeader **headers, char *authKey);

/* construct_response()
 * --------------------
 * Process the request and construct the needed response
 *
 * req: the request parameters
 * stringStores: the db to update keys
 *
 * Returns: the required response
 */
char *construct_response(struct RequestParams req, StringStore **stringStores);

/* get_path_key()
 * --------------
 * Gets the needed path and key from the supplied address
 *
 * address: the address given by the HTTP request
 * path: the pointer to the path variable to update
 * key: the pointer to the key variable to update
 */
int get_path_key(char *address, char **path, char **key);

/* request_params_init()
 * ---------------------
 * Initialise the requestParams struct
 *
 * Returns: the initialised requestParams struct
 */
struct RequestParams request_params_init(void);

/* handle_connection_request()
 * ---------------------------
 * Handles the clients request
 *
 * recv: the connection file to read from
 * send: the connection file to write to
 * authKey: the authorization key for the private db
 * stringStores: the arrays of dbs
 */
int handle_connection_request(
        FILE *recv, FILE *send, char *authKey, StringStore **stringStores);

/* handle_client_connection()
 * ---------------------------
 * Handles the connection through the given fd
 *
 * fd: the fd to send and recieve information for the connection on
 * authKey: the authorization key for the private db
 * stringStores: the array of dbs
 */
void handle_client_connection(
        int fd, char *authKey, StringStore **stringStores);

/* handle_connection()
 * -------------------
 * Thread function for handling connections to the server, if there are too
 * many connections the server will turn away the client
 *
 * ciPtr: the pointer to the connection information
 */
void *handle_connection(void *ciPtr);

/* print_server_stats()
 * --------------------
 * Prints the server statistics. used by SIGHUP handler
 *
 * s: the signal from the signal handler
 */
void print_server_stats(int s);

/* setup_signal_handler()
 * ----------------------
 * Sets up the signal handler for SIGHUP
 */
void setup_signal_handler(void);

#endif