#pragma once

#include <dlfcn.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//
#include "common.c"

typedef uint8_t byte;

// contracts

void                               __init_plugin_func(void);
typedef typeof(__init_plugin_func) init_plugin;

struct relay_info;
struct relay_neighbor;
struct data_packet;

// runs when the server wants to respond to a server audit request
void __modify_server_stats_func(struct relay_info *server_stats);
typedef typeof(__modify_server_stats_func) modify_server_stats;

// runs when the server wants to decide whether to add a neighbor by request or not
bool __decide_neighbor_registry_func(struct relay_neighbor new_neighbor);
typedef typeof(__decide_neighbor_registry_func) decide_neighbor_registry;

// runs when the server wants to decide whether to propagate
bool __decide_packet_propogation_func(struct data_packet packet);
typedef typeof(__decide_packet_propogation_func) decide_packet_propogation;

// runs before the paste_server function performs any logic
void __paste_server_start_func(
    char   **ip_addr_ref,
    size_t  *ip_size_ref,
    byte   **in_ref,
    size_t  *in_len_ref,
    byte  ***out_ref,
    size_t **out_len_ref);
typedef typeof(__paste_server_start_func) paste_server_start;

// runs when the server wants to decide whether to save the packet to disk
bool __decide_packet_save_to_disk_func(struct data_packet packet);
typedef typeof(__decide_packet_save_to_disk_func) decide_packet_save_to_disk;

// runs when the server wants a plugin to modify a packet (e.g., keepalive, run PoW, etc)
void                                 __modify_packet_func(struct data_packet *packet);
typedef typeof(__modify_packet_func) modify_packet;

// runs when the server wants to decide whether to wipe a packet
bool __decide_packet_cleanup_func(struct data_packet packet);
typedef typeof(__decide_packet_cleanup_func) decide_packet_cleanup;

// runs when the server logs a message
void                              __custom_log_func(int level, const char *msg);
typedef typeof(__custom_log_func) custom_log;

// runs when the server is shutting down
void                                      __on_server_shutdown_func(void);
typedef typeof(__on_server_shutdown_func) on_server_shutdown;

// data

enum plugin_handler_code_types {
    code_modify_server_stats        = 1,
    code_decide_neighbor_registry   = 2,
    code_decide_packet_propogation  = 3,
    code_paste_server_start         = 4,
    code_decide_packet_save_to_disk = 5,
    code_modify_packet              = 6,
    code_decide_packet_cleanup      = 7,
    code_on_server_shutdown         = 8,
    code_custom_log                 = 9
};

void                       *plugin_handle                   = NULL;
init_plugin                *init_plugin_func                = NULL;
modify_server_stats        *modify_server_stats_func        = NULL;
decide_neighbor_registry   *decide_neighbor_registry_func   = NULL;
decide_packet_propogation  *decide_packet_propogation_func  = NULL;
paste_server_start         *paste_server_start_func         = NULL;
decide_packet_save_to_disk *decide_packet_save_to_disk_func = NULL;
modify_packet              *modify_packet_func              = NULL;
decide_packet_cleanup      *decide_packet_cleanup_func      = NULL;
custom_log                 *custom_log_func                 = NULL;
on_server_shutdown         *on_server_shutdown_func         = NULL; // unused for now

pthread_mutex_t plugin_mutex = PTHREAD_MUTEX_INITIALIZER;

// implementation

void load_plugins(const char *plugin_path) {
    pthread_mutex_lock(&plugin_mutex);
    if (plugin_handle) {
        dlclose(plugin_handle);
        plugin_handle                   = NULL;
        init_plugin_func                = NULL;
        modify_server_stats_func        = NULL;
        decide_neighbor_registry_func   = NULL;
        decide_packet_propogation_func  = NULL;
        paste_server_start_func         = NULL;
        decide_packet_save_to_disk_func = NULL;
        modify_packet_func              = NULL;
        decide_packet_cleanup_func      = NULL;
        custom_log_func                 = NULL;
        on_server_shutdown_func         = NULL;
    }

    plugin_handle = dlopen(plugin_path, RTLD_NOW);
    if (!plugin_handle) {
        fprintf(stderr, "%s\n", dlerror());
        pthread_mutex_unlock(&plugin_mutex);
        return;
    }

    if (init_plugin_func) {
        init_plugin_func();
        log(_info, "loaded %s\n", plugin_path);
    } else {
        log(_error, "%s has no MP_init_plugin", plugin_path);
        dlclose(plugin_handle);
        plugin_handle = NULL;
        pthread_mutex_unlock(&plugin_mutex);
        return;
    }

    init_plugin_func                = dlsym(plugin_handle, "MP_init_plugin");
    modify_server_stats_func        = dlsym(plugin_handle, "MP_modify_server_stats");
    decide_neighbor_registry_func   = dlsym(plugin_handle, "MP_decide_neighbor_registry");
    decide_packet_propogation_func  = dlsym(plugin_handle, "MP_decide_packet_propogation");
    paste_server_start_func         = dlsym(plugin_handle, "MP_paste_server_start");
    decide_packet_save_to_disk_func = dlsym(plugin_handle, "MP_decide_packet_save_to_disk");
    modify_packet_func              = dlsym(plugin_handle, "MP_modify_packet");
    decide_packet_cleanup_func      = dlsym(plugin_handle, "MP_decide_packet_cleanup");
    custom_log_func                 = dlsym(plugin_handle, "MP_custom_log");
    on_server_shutdown_func         = dlsym(plugin_handle, "MP_on_server_shutdown");

    pthread_mutex_unlock(&plugin_mutex);
}

void cleanup_plugins(void) {
    pthread_mutex_lock(&plugin_mutex);
    if (plugin_handle) {
        if (on_server_shutdown_func) { on_server_shutdown_func(); }
        dlclose(plugin_handle);
        plugin_handle                   = NULL;
        init_plugin_func                = NULL;
        modify_server_stats_func        = NULL;
        decide_neighbor_registry_func   = NULL;
        decide_packet_propogation_func  = NULL;
        paste_server_start_func         = NULL;
        decide_packet_save_to_disk_func = NULL;
        modify_packet_func              = NULL;
        decide_packet_cleanup_func      = NULL;
        custom_log_func                 = NULL;
        on_server_shutdown_func         = NULL;
    }
    pthread_mutex_unlock(&plugin_mutex);
}