#include <arpa/inet.h>
#include <json-c/json.h>
#include <signal.h>
#include <sqlite3.h>
#include <string.h>
#include <threads.h>

#include "logger.c"
#include "sql.c"

#define BACKLOG 10

struct Socket {
    int fd;
    struct sockaddr_in addr;
};

struct json_object *g_response_header;

// ----------------------------------------------------------------------------
// SQL callbacks
// ----------------------------------------------------------------------------
void sql_callback_add_column_name(sqlite3_stmt *sql_stmt, void *data) {
    assert(sql_stmt);
    assert(data);
    assert(sqlite3_column_type(sql_stmt, 0) == SQLITE_TEXT);
    assert(!strcmp(sqlite3_column_name(sql_stmt, 0), "name"));

    const char *col_name = (const char *)sqlite3_column_text(sql_stmt, 0);
    struct json_object *response = (struct json_object *)data;

    if (!json_object_object_get_ex(response, col_name, NULL)) {
        json_object_object_add(response, col_name, json_object_new_array());
    }
}

void sql_callback_add_data(sqlite3_stmt *sql_stmt, void *data) {
    assert(sql_stmt);
    assert(data);

    struct json_object *response = (struct json_object *)data;

    for (int i = 0; i < sqlite3_column_count(sql_stmt); i++) {
        const char *col_name = sqlite3_column_name(sql_stmt, i);
        struct json_object *col_data = json_object_object_get(response, col_name);

        if (col_data) {
            if (sqlite3_column_type(sql_stmt, i) == SQLITE_BLOB) {
                // TODO: render blobs in parallel
            } else {
                json_object_array_add(col_data, json_object_new_int64(sqlite3_column_int64(sql_stmt, i)));
            }
        }
    }
}

// ----------------------------------------------------------------------------
// Main functions
// ----------------------------------------------------------------------------
void sig_handler(int signo) {
    (void)signo;
    log_warn("Signal received, will stop SALIS data server");
    json_object_put(g_response_header);
    sql_close();
    exit(0);
}

void respond_name(int socket_fd) {
    log_info("Client requested simulation name");

    struct json_object *sim_name = json_object_new_object();
    json_object_object_add(sim_name, "name", json_object_new_string(NAME));
    json_object_to_fd(socket_fd, sim_name, 0);
    json_object_put(sim_name);
}

void respond_opts(int socket_fd) {
    log_info("Client requested simulation options");

    struct json_object *sim_opts = json_object_from_file(SIM_OPTS);
    json_object_to_fd(socket_fd, sim_opts, 0);
    json_object_put(sim_opts);
}

void respond_hash(int socket_fd) {
    log_info("Client requested git hash");

    char buff[41] = { 0 };
    FILE *pipe = popen("git rev-parse HEAD", "r");
    fread(buff, sizeof(char), 40, pipe);
    pclose(pipe);

    struct json_object *git_hash = json_object_new_object();
    json_object_object_add(git_hash, "hash", json_object_new_string(buff));
    json_object_to_fd(socket_fd, git_hash, 0);
    json_object_put(git_hash);
}

void respond_data(int socket_fd, struct json_object *request) {
    assert(request);

    const char *request_str = json_object_to_json_string(request);
    log_info("Client requested simulation data with the following parameters: %s", request_str);
    const char *x_axis = json_object_get_string(json_object_object_get(request, "x-axis"));
    int64_t x_current = json_object_get_int64(json_object_object_get(request, "x-current"));
    int64_t x_high = json_object_get_int64(json_object_object_get(request, "x-high"));
    int64_t nth = json_object_get_int64(json_object_object_get(request, "nth"));
    int64_t entries = json_object_get_int64(json_object_object_get(request, "entries"));

    const char *x_axis_pref = (!strcmp(x_axis, "rowid") || !strcmp(x_axis, "step")) ? "core." : "";

    struct json_object *response = NULL;
    json_object_deep_copy(g_response_header, &response, NULL);

    sql_exec(
        0, NULL, NULL,
        sql_callback_add_data,
        response,
        "select * from ("
            "select core.rowid, core.step, * from core inner join arch "
            "where core.rowid = arch.rowid and %s%s > %ld and %s%s <= %ld and core.rowid %% %ld == 0 "
            "order by %s%s desc limit %ld"
        ") order by %s asc;",
        x_axis_pref,
        x_axis,
        x_current,
        x_axis_pref,
        x_axis,
        x_high,
        nth,
        x_axis_pref,
        x_axis,
        entries,
        x_axis
    );

    const char *response_str = json_object_to_json_string(response);
    log_info("Responding to client with: %s", response_str);
    json_object_to_fd(socket_fd, response, 0);
    json_object_put(response);

    shutdown(socket_fd, SHUT_WR);
}

int handle_client(struct Socket *socket) {
    assert(socket);

    char socket_ip[INET_ADDRSTRLEN];
    inet_ntop(AF_INET, &socket->addr.sin_addr, socket_ip, INET_ADDRSTRLEN);
    log_info("Client connected: %s:%d", socket_ip, ntohs(socket->addr.sin_port));

    struct json_object *request_json = json_object_from_fd(socket->fd);
    struct json_object *request_str = NULL;

    if (!json_object_object_get_ex(request_json, "request", &request_str)) assert(false);

    const char *request = json_object_get_string(request_str);
    assert(request);

    if (!strcmp(request, "name")) {
        respond_name(socket->fd);
    } else if (!strcmp(request, "opts")) {
        respond_opts(socket->fd);
    } else if (!strcmp(request, "hash")) {
        respond_hash(socket->fd);
    } else if (!strcmp(request, "data")) {
        respond_data(socket->fd, request_json);
    } else {
        assert(false);
    }

    json_object_put(request_json);

    log_info("Client disconnected: %s:%d", socket_ip, ntohs(socket->addr.sin_port));
    close(socket->fd);

    free(socket);
    return 0;
}

int main(void) {
    log_info("Initializing salis data server");
    log_info("Connecting to database in: %s", DATA_PUSH_PATH);
    sql_open();

    signal(SIGINT, sig_handler);
    signal(SIGTERM, sig_handler);

    log_info("Creating response header");
    g_response_header = json_object_new_object();
    json_object_object_add(g_response_header, "rowid", json_object_new_array());
    sql_exec(
        0, NULL, NULL,
        sql_callback_add_column_name,
        g_response_header,
        "select name from pragma_table_info('core') union "
        "select name from pragma_table_info('arch');"
    );

    log_info("Binding to port: %d", PORT);
    int opt = 1;
    int socket_fd = socket(AF_INET, SOCK_STREAM, 0);
    setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
    struct sockaddr_in socket_addr = { 0 };
    socket_addr.sin_family = AF_INET;
    socket_addr.sin_addr.s_addr = INADDR_ANY;
    socket_addr.sin_port = htons(PORT);
    bind(socket_fd, (struct sockaddr *)&socket_addr, sizeof(struct sockaddr_in));

    listen(socket_fd, BACKLOG);
    log_info("Listening...");

    while (true) {
        struct Socket *socket = calloc(1, sizeof(struct Socket));
        socklen_t socket_len = sizeof(struct sockaddr_in);
        socket->fd = accept(socket_fd, (struct sockaddr *)&socket->addr, &socket_len);

        thrd_t thrd;
        thrd_create(&thrd, (thrd_start_t)handle_client, socket);
        thrd_detach(thrd);
    }

    return 0;
}