/*
 *  Guacamole - Clientless Remote Desktop
 *  Copyright (C) 2010  Michael Jumper
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <uuid/uuid.h>

#include "guacio.h"
#include "protocol.h"
#include "client.h"



guac_client_registry_node* guac_create_client_registry() {

    guac_client_registry_node* registry = malloc(sizeof(guac_client_registry_node));

    registry->used = 0;
    memset(registry->next, 0, sizeof(registry->next));

    return registry;

}

void guac_register_client(guac_client_registry_node* registry, guac_client* client) {

    guac_client_registry_node* current = registry;
    int i;
    unsigned char index;

    for (i=0; i<sizeof(uuid_t)-1; i++) {

        guac_client_registry_node* next;

        /* Get next registry node */
        index = ((unsigned char*) client->uuid)[i];
        next = ((guac_client_registry_node**) current->next)[index];

        /* If no node, allocate one */
        if (next == NULL) {
            current->used++;
            next = guac_create_client_registry();
            ((guac_client_registry_node**) current->next)[index] = next;
        }

        current = next;
    }

    /* Register client */
    index = ((unsigned char*) client->uuid)[i];
    ((guac_client**) current->next)[index] = client;

}

guac_client* guac_find_client(guac_client_registry_node* registry, uuid_t uuid) {

    guac_client_registry_node* current = registry;
    int i;
    unsigned char index;

    for (i=0; i<sizeof(uuid_t)-1; i++) {

        /* Get next registry node */
        index = ((unsigned char*) uuid)[i];
        current = ((guac_client_registry_node**) current->next)[index];

        /* If no node, client not registered */
        if (current == NULL)
            return NULL;

    }

    /* Return client found (if any) */
    index = ((unsigned char*) uuid)[i];
    return ((guac_client**) current->next)[index];

}

void guac_remove_client(guac_client_registry_node* registry, guac_client* client) {

    guac_client_registry_node* current = registry;
    int i;
    unsigned char index;

    for (i=0; i<sizeof(uuid_t)-1; i++) {

        /* Get next registry node */
        index = ((unsigned char*) client->uuid)[i];
        current = ((guac_client_registry_node**) current->next)[index];

        /* If no node, client not registered */
        if (current == NULL)
            return;

    }

    /* Remove client, if registered */
    if (((guac_client**) current->next)[index]) {
        ((guac_client**) current->next)[index] = NULL;
        current->used--;

        /* FIXME: If no more clients at this node, clean up */
        if (current->used == 0) {
            /* STUB */
        }

    }

}

void guac_cleanup_client_registry(guac_client_registry_node* registry) {

    int i;
    for (i=0; i<sizeof(registry->next); i++) {

        if (registry->next[i] != NULL) {
            guac_cleanup_client_registry(registry->next[i]);
            registry->next[i] = NULL;
        }

    }

    free(registry);

}



png_byte** guac_alloc_png_buffer(int w, int h, int bpp) {

    png_byte** png_buffer;
    png_byte* row;
    int y;

    /* Allocate rows for PNG */
    png_buffer = (png_byte**) malloc(h * sizeof(png_byte*));
    for (y=0; y<h; y++) {
        row = (png_byte*) malloc(sizeof(png_byte) * bpp * w);
        png_buffer[y] = row;
    }

    return png_buffer;
}

void guac_free_png_buffer(png_byte** png_buffer, int h) {

    int y;

    /* Free PNG data */
    for (y = 0; y<h; y++)
        free(png_buffer[y]);
    free(png_buffer);

}

guac_client* __guac_alloc_client(GUACIO* io) {

    /* Allocate new client (not handoff) */
    guac_client* client = malloc(sizeof(guac_client));

    /* Init new client */
    client->io = io;
    uuid_generate(client->uuid);
    strncpy((char*) client->uuid, "0123456789ABCDEF", 16);

    return client;
}


guac_client* guac_get_client(int client_fd, guac_client_registry_node* registry, guac_client_init_handler* client_init, int argc, char** argv) {

    guac_client* client;
    GUACIO* io = guac_open(client_fd);
    guac_instruction instruction;

    /* Make copies of arguments */
    char** safe_argv = malloc(argc * sizeof(char*));
    char** scratch_argv = malloc(argc * sizeof(char*));

    int i;
    for (i=0; i<argc; i++)
        scratch_argv[i] = safe_argv[i] = strdup(argv[i]);

    /* Wait for handshaking messages */
    for (;;) {

        int retval;
        retval = guac_read_instruction(io, &instruction); /* 0 if no instructions finished yet, <0 if error or EOF */

        if (retval > 0) {
           
            /* connect -> create new client connection */
            if (strcmp(instruction.opcode, "connect") == 0) {
                
                /* Create new client */
                client = __guac_alloc_client(io);

                /* Register client */
                if (registry) {
                    guac_register_client(registry, client);

                    /* Send UUID to web-client */
                    guac_send_uuid(io, client->uuid);
                    guac_flush(client->io);
                }

                client_init(client, argc, scratch_argv);
                break;
            }

            if (strcmp(instruction.opcode, "handoff") == 0) {
                
                fprintf(stderr, "HANDOFF!\n");

                /* Get UUID from instruction */
                guac_decode_base64_inplace(instruction.argv[0]);

                fprintf(stderr, "Decoded.\n");

                /* Find client associated with UUID*/
                if (registry) {
                    fprintf(stderr, "Locating.\n");
                    client = guac_find_client(registry, (unsigned char*) "0123456789ABCDEF" /*instruction.argv[0]*/);
                    fprintf(stderr, "@%p\n", (void*) client);

                    /* Transfer client I/O to new connection, if client exists */
                    if (client) {

                        int fd = client->io->fd;
                        guac_close(client->io);
                        close(fd);

                        client->io = io;
                        break;
                    }
                    /* TODO: Send error if client not found */

                    fprintf(stderr, "OK\n");
                }
                
                /* TODO: Send error if handoff sent to client without registry */

            }

        }

        if (retval < 0)
            return NULL; /* EOF or error */

        /* Otherwise, retval == 0 implies unfinished instruction */

    }

    /* Free memory used for arg copy */
    for (i=0; i<argc; i++)
        free(safe_argv[i]);
    
    free(safe_argv);
    free(scratch_argv);

    return client;

}


void guac_free_client(guac_client* client, guac_client_registry_node* registry) {

    if (client->free_handler)
        client->free_handler(client);

    guac_close(client->io);

    guac_remove_client(registry, client);

    free(client);
}


void guac_start_client(guac_client* client) {

    guac_instruction instruction;
    GUACIO* io = client->io;
    int wait_result;

    /* VNC Client Loop */
    for (;;) {

        /* Handle server messages */
        if (client->handle_messages) {
            client->handle_messages(client);
            guac_flush(client->io);
        }

        wait_result = guac_instructions_waiting(io);
        if (wait_result > 0) {

            int retval;
            retval = guac_read_instruction(io, &instruction); /* 0 if no instructions finished yet, <0 if error or EOF */

            if (retval > 0) {
           
                do {

                    if (strcmp(instruction.opcode, "mouse") == 0) {
                        if (client->mouse_handler)
                            client->mouse_handler(
                                client,
                                atoi(instruction.argv[0]), /* x */
                                atoi(instruction.argv[1]), /* y */
                                atoi(instruction.argv[2])  /* mask */
                            );
                    }

                    else if (strcmp(instruction.opcode, "key") == 0) {
                        if (client->key_handler)
                            client->key_handler(
                                client,
                                atoi(instruction.argv[0]), /* keysym */
                                atoi(instruction.argv[1])  /* pressed */
                            );
                    }

                    else if (strcmp(instruction.opcode, "clipboard") == 0) {
                        if (client->clipboard_handler)
                            client->clipboard_handler(
                                client,
                                guac_unescape_string_inplace(instruction.argv[0]) /* data */
                            );
                    }

                    else if (strcmp(instruction.opcode, "disconnect") == 0) {
                        return;
                    }

                } while ((retval = guac_read_instruction(io, &instruction)) > 0);

                if (retval < 0)
                    return;
            }

            if (retval < 0)
                return; /* EOF or error */

            /* Otherwise, retval == 0 implies unfinished instruction */

        }
        else if (wait_result < 0)
            return;

    }

}