/*
 * fec_manager.h
 *
 *  Created on: Sep 27, 2017
 *      Author: root
 */

#ifndef FEC_MANAGER_H_
#define FEC_MANAGER_H_

#include "common.h"
#include "log.h"
#include "lib/rs.h"

const int max_blob_packet_num = 30000;      // how many packet can be contain in a blob_t ,can be set very large
const u32_t anti_replay_buff_size = 30000;  // can be set very large

const int max_fec_packet_num = 255;  // this is the limitation of the rs lib
extern u32_t fec_buff_num;

const int rs_str_len = max_fec_packet_num * 10 + 100;
extern int header_overhead;
extern int debug_fec_enc;
extern int debug_fec_dec;

struct fec_parameter_t {
    int version = 0;
    int mtu = default_mtu;
    int queue_len = 200;
    int timeout = 8 * 1000;
    int mode = 0;

    int rs_cnt = 0;
    struct rs_parameter_t  // parameters for reed solomon
    {
        unsigned char x;  // AKA fec_data_num  (x should be same as <index of rs_par>+1 at the moment)
        unsigned char y;  // fec_redundant_num
    } rs_par[max_fec_packet_num + 10];

    int rs_from_str(char *s)  // todo inefficient
    {
        vector<string> str_vec = string_to_vec(s, ",");
        if (str_vec.size() < 1) {
            mylog(log_warn, "failed to parse [%s]\n", s);
            return -1;
        }
        vector<rs_parameter_t> par_vec;
        for (int i = 0; i < (int)str_vec.size(); i++) {
            rs_parameter_t tmp_par;
            string &tmp_str = str_vec[i];
            int x, y;
            if (sscanf((char *)tmp_str.c_str(), "%d:%d", &x, &y) != 2) {
                mylog(log_warn, "failed to parse [%s]\n", tmp_str.c_str());
                return -1;
            }
            if (x < 1 || y < 0 || x + y > max_fec_packet_num) {
                mylog(log_warn, "invaild value x=%d y=%d, x should >=1, y should >=0, x +y should <%d\n", x, y, max_fec_packet_num);
                return -1;
            }
            tmp_par.x = x;
            tmp_par.y = y;
            par_vec.push_back(tmp_par);
        }
        assert(par_vec.size() == str_vec.size());

        int found_problem = 0;
        for (int i = 1; i < (int)par_vec.size(); i++) {
            if (par_vec[i].x <= par_vec[i - 1].x) {
                mylog(log_warn, "error in [%s], x in x:y should be in ascend order\n", s);
                return -1;
            }
            int now_x = par_vec[i].x;
            int now_y = par_vec[i].y;
            int pre_x = par_vec[i - 1].x;
            int pre_y = par_vec[i - 1].y;

            double now_ratio = double(par_vec[i].y) / par_vec[i].x;
            double pre_ratio = double(par_vec[i - 1].y) / par_vec[i - 1].x;

            if (pre_ratio + 0.0001 < now_ratio) {
                if (found_problem == 0) {
                    mylog(log_warn, "possible problems: %d/%d<%d/%d", pre_y, pre_x, now_y, now_x);
                    found_problem = 1;
                } else {
                    log_bare(log_warn, ", %d/%d<%d/%d", pre_y, pre_x, now_y, now_x);
                }
            }
        }
        if (found_problem) {
            log_bare(log_warn, " in %s\n", s);
        }

        {  // special treatment for first parameter
            int x = par_vec[0].x;
            int y = par_vec[0].y;
            for (int i = 1; i <= x; i++) {
                rs_par[i - 1].x = i;
                rs_par[i - 1].y = y;
            }
        }

        for (int i = 1; i < (int)par_vec.size(); i++) {
            int now_x = par_vec[i].x;
            int now_y = par_vec[i].y;
            int pre_x = par_vec[i - 1].x;
            int pre_y = par_vec[i - 1].y;
            rs_par[now_x - 1].x = now_x;
            rs_par[now_x - 1].y = now_y;

            double now_ratio = double(par_vec[i].y) / par_vec[i].x;
            double pre_ratio = double(par_vec[i - 1].y) / par_vec[i - 1].x;

            // double k= double(now_y-pre_y)/double(now_x-pre_x);
            for (int j = pre_x + 1; j <= now_x - 1; j++) {
                int in_x = j;

                ////////	int in_y= double(pre_y) + double(in_x-pre_x)*k+ 0.9999;// round to upper

                double distance = now_x - pre_x;
                ///////	double in_ratio=pre_ratio*(1.0-(in_x-pre_x)/distance)   +   now_ratio *(1.0- (now_x-in_x)/distance);
                //////	int in_y= in_x*in_ratio + 0.9999;
                int in_y = pre_y + (now_y - pre_y) * (in_x - pre_x) / distance + 0.9999;

                if (in_x + in_y > max_fec_packet_num) {
                    in_y = max_fec_packet_num - in_x;
                    assert(in_y >= 0 && in_y <= max_fec_packet_num);
                }

                rs_par[in_x - 1].x = in_x;
                rs_par[in_x - 1].y = in_y;
            }
        }
        rs_cnt = par_vec[par_vec.size() - 1].x;

        return 0;
    }

    char *rs_to_str()  // todo inefficient
    {
        static char res[rs_str_len];
        string tmp_string;
        char tmp_buf[100];
        assert(rs_cnt >= 1);
        for (int i = 0; i < rs_cnt; i++) {
            sprintf(tmp_buf, "%d:%d", int(rs_par[i].x), int(rs_par[i].y));
            if (i != 0)
                tmp_string += ",";
            tmp_string += tmp_buf;
        }
        strcpy(res, tmp_string.c_str());
        return res;
    }

    rs_parameter_t get_tail() {
        assert(rs_cnt >= 1);
        return rs_par[rs_cnt - 1];
    }

    int clone(fec_parameter_t &other) {
        version = other.version;
        mtu = other.mtu;
        queue_len = other.queue_len;
        timeout = other.timeout;
        mode = other.mode;

        assert(other.rs_cnt >= 1);
        rs_cnt = other.rs_cnt;
        memcpy(rs_par, other.rs_par, sizeof(rs_parameter_t) * rs_cnt);

        return 0;
    }

    int copy_fec(fec_parameter_t &other) {
        assert(other.rs_cnt >= 1);
        rs_cnt = other.rs_cnt;
        memcpy(rs_par, other.rs_par, sizeof(rs_parameter_t) * rs_cnt);

        return 0;
    }
};

extern fec_parameter_t g_fec_par;
// extern int dynamic_update_fec;

const int anti_replay_timeout = 120 * 1000;  // 120s

struct anti_replay_t {
    struct info_t {
        my_time_t my_time;
        int index;
    };

    u64_t replay_buffer[anti_replay_buff_size];
    unordered_map<u32_t, info_t> mp;
    int index;
    anti_replay_t() {
        clear();
    }
    int clear() {
        memset(replay_buffer, -1, sizeof(replay_buffer));
        mp.clear();
        mp.rehash(anti_replay_buff_size * 3);
        index = 0;
        return 0;
    }
    void set_invaild(u32_t seq) {
        if (is_vaild(seq) == 0) {
            mylog(log_trace, "seq %u exist\n", seq);
            // assert(mp.find(seq)!=mp.end());
            // mp[seq].my_time=get_current_time_rough();
            return;
        }
        if (replay_buffer[index] != u64_t(i64_t(-1))) {
            assert(mp.find(replay_buffer[index]) != mp.end());
            mp.erase(replay_buffer[index]);
        }
        replay_buffer[index] = seq;
        assert(mp.find(seq) == mp.end());
        mp[seq].my_time = get_current_time();
        mp[seq].index = index;
        index++;
        if (index == int(anti_replay_buff_size)) index = 0;
    }
    int is_vaild(u32_t seq) {
        if (mp.find(seq) == mp.end()) return 1;

        if (get_current_time() - mp[seq].my_time > anti_replay_timeout) {
            replay_buffer[mp[seq].index] = u64_t(i64_t(-1));
            mp.erase(seq);
            return 1;
        }

        return 0;
    }
};

struct blob_encode_t {
    char input_buf[(max_fec_packet_num + 5) * buf_len];
    int current_len;
    int counter;

    char *output_buf[max_fec_packet_num + 100];

    blob_encode_t();

    int clear();

    int get_num();
    int get_shard_len(int n);
    int get_shard_len(int n, int next_packet_len);

    int input(char *s, int len);  // len=use len=0 for second and following packet
    int output(int n, char **&s_arr, int &len);
};

struct blob_decode_t {
    char input_buf[(max_fec_packet_num + 5) * buf_len];
    int current_len;
    int last_len;
    int counter;

    char *output_buf[max_blob_packet_num + 100];
    int output_len[max_blob_packet_num + 100];

    blob_decode_t();
    int clear();
    int input(char *input, int len);
    int output(int &n, char **&output, int *&len_arr);
};

class fec_encode_manager_t : not_copy_able_t {
   private:
    u32_t seq;

    // int fec_mode;
    // int fec_data_num,fec_redundant_num;
    // int fec_mtu;
    // int fec_queue_len;
    // int fec_timeout;
    fec_parameter_t fec_par;

    my_time_t first_packet_time;
    my_time_t first_packet_time_for_output;

    blob_encode_t blob_encode;
    char input_buf[max_fec_packet_num + 5][buf_len];
    int input_len[max_fec_packet_num + 100];

    char *output_buf[max_fec_packet_num + 100];
    int output_len[max_fec_packet_num + 100];

    int counter;
    // int timer_fd;
    // u64_t timer_fd64;

    int ready_for_output;
    u32_t output_n;

    int append(char *s, int len);

    ev_timer timer;
    struct ev_loop *loop = 0;
    void (*cb)(struct ev_loop *loop, struct ev_timer *watcher, int revents) = 0;

   public:
    fec_encode_manager_t();
    ~fec_encode_manager_t();

    fec_parameter_t &get_fec_par() {
        return fec_par;
    }
    void set_data(void *data) {
        timer.data = data;
    }

    void set_loop_and_cb(struct ev_loop *loop, void (*cb)(struct ev_loop *loop, struct ev_timer *watcher, int revents)) {
        this->loop = loop;
        this->cb = cb;
        ev_init(&timer, cb);
    }

    int clear_data() {
        counter = 0;
        blob_encode.clear();
        ready_for_output = 0;

        seq = (u32_t)get_fake_random_number();  // TODO temp solution for a bug.

        if (loop) {
            ev_timer_stop(loop, &timer);
        }
        return 0;
    }
    int clear_all() {
        // itimerspec zero_its;
        // memset(&zero_its, 0, sizeof(zero_its));
        // timerfd_settime(timer_fd, TFD_TIMER_ABSTIME, &zero_its, 0);

        if (loop) {
            ev_timer_stop(loop, &timer);
            loop = 0;
            cb = 0;
        }

        clear_data();

        return 0;
    }

    my_time_t get_first_packet_time() {
        return first_packet_time_for_output;
    }

    int get_pending_time() {
        return fec_par.timeout;
    }

    int get_type() {
        return fec_par.mode;
    }
    // u64_t get_timer_fd64();
    int reset_fec_parameter(int data_num, int redundant_num, int mtu, int pending_num, int pending_time, int type);
    int input(char *s, int len /*,int &is_first_packet*/);
    int output(int &n, char **&s_arr, int *&len);
};
struct fec_data_t {
    int used;
    u32_t seq;
    int type;
    int data_num;
    int redundant_num;
    int idx;
    char buf[buf_len];
    int len;
};
struct fec_group_t {
    int type = -1;
    int data_num = -1;
    int redundant_num = -1;
    int len = -1;
    int fec_done = 0;
    // int data_counter=0;
    map<int, int> group_mp;
};
class fec_decode_manager_t : not_copy_able_t {
    anti_replay_t anti_replay;
    fec_data_t *fec_data = 0;
    unordered_map<u32_t, fec_group_t> mp;
    blob_decode_t blob_decode;

    int index;

    int output_n;
    char **output_s_arr;
    int *output_len_arr;
    int ready_for_output;

    char *output_s_arr_buf[max_fec_packet_num + 100];  // only for type=1,for type=0 the buf inside blot_t is used
    int output_len_arr_buf[max_fec_packet_num + 100];  // same

   public:
    fec_decode_manager_t() {
        fec_data = new fec_data_t[fec_buff_num + 5];
        assert(fec_data != 0);
        clear();
    }
    /*
    fec_decode_manager_t(const fec_decode_manager_t &b)
    {
            assert(0==1);//not allowed to copy
    }*/
    ~fec_decode_manager_t() {
        mylog(log_debug, "fec_decode_manager destroyed\n");
        if (fec_data != 0) {
            mylog(log_debug, "fec_data freed\n");
            delete[] fec_data;
        }
    }
    int clear() {
        anti_replay.clear();
        mp.clear();
        mp.rehash(fec_buff_num * 3);

        for (int i = 0; i < (int)fec_buff_num; i++)
            fec_data[i].used = 0;
        ready_for_output = 0;
        index = 0;

        return 0;
    }

    // int re_init();
    int input(char *s, int len);
    int output(int &n, char **&s_arr, int *&len_arr);
};

#endif /* FEC_MANAGER_H_ */