#include "naut/naut_plugin.h"

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

typedef struct {
    uint8_t *data;
    size_t capacity;
} memory_storage;

static unsigned finished_events;

static void *memory_open(const char *root, naut_err *error) {
    (void)root;
    memory_storage *storage = calloc(1, sizeof(*storage));
    if (!storage) {
        *error = NAUT_ERR_NOMEM;
        return NULL;
    }
    storage->capacity = 1u << 20;
    storage->data = calloc(1, storage->capacity);
    if (!storage->data) {
        free(storage);
        *error = NAUT_ERR_NOMEM;
        return NULL;
    }
    *error = NAUT_OK;
    return storage;
}

static void memory_close(void *opaque) {
    memory_storage *storage = opaque;
    free(storage->data);
    free(storage);
}

static naut_err memory_read(void *opaque, int64_t offset,
                            void *buffer, size_t length) {
    memory_storage *storage = opaque;
    if (offset < 0 || (uint64_t)offset + length > storage->capacity)
        return NAUT_ERR_RANGE;
    memcpy(buffer, storage->data + offset, length);
    return NAUT_OK;
}

static naut_err memory_write(void *opaque, int64_t offset,
                             const void *buffer, size_t length) {
    memory_storage *storage = opaque;
    if (offset < 0 || (uint64_t)offset + length > storage->capacity)
        return NAUT_ERR_RANGE;
    memcpy(storage->data + offset, buffer, length);
    return NAUT_OK;
}

static naut_err example_events(void *context, const char *request,
                               char **response) {
    (void)context;
    (void)request;
    char buffer[64];
    snprintf(buffer, sizeof buffer, "{\"finished\":%u}", finished_events);
    *response = strdup(buffer);
    return *response ? NAUT_OK : NAUT_ERR_NOMEM;
}

static void on_event(void *context, const naut_event *event) {
    (void)context;
    if (event->type == NAUT_EVENT_TORRENT_FINISHED) finished_events++;
}

naut_err naut_plugin_register(const naut_host_api *host) {
    if (!host || host->abi_version != NAUT_PLUGIN_ABI_VERSION ||
        host->struct_size < sizeof(*host))
        return NAUT_ERR_INVAL;
    static const naut_storage_backend_v1 storage = {
        .abi_version = NAUT_PLUGIN_ABI_VERSION,
        .struct_size = sizeof(storage),
        .name = "memory",
        .open = memory_open,
        .close = memory_close,
        .read = memory_read,
        .write = memory_write,
    };
    naut_err error = host->set_plugin_name(host->host_context, "example");
    if (error == NAUT_OK)
        error = host->register_storage_backend(host->host_context, &storage);
    if (error == NAUT_OK)
        error = host->register_rpc(host->host_context, "example.events",
                                   example_events, NULL);
    if (error == NAUT_OK)
        error = host->subscribe_event(host->host_context, on_event, NULL);
    return error;
}