/**
 * Request
 * Cmd: 	| OP(1) | argc(1) | repeat { arglen(4) | arg } |
 * 
 * Response
 * Rsp:		| OP(1) | status(1) | datalen(4) | data | 
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#define CMD_SIZE (1024)
#define BATCH_SIZE (65536)
#define KVS_BATCH_MAX 128
#define TIME_SUB_MS(tv1, tv2)  ((tv1.tv_sec - tv2.tv_sec) * 1000 + (tv1.tv_usec - tv2.tv_usec) / 1000)

// #define PRESP  print_response
#define PRESP


typedef enum {
	KVS_STATUS_OK = 0,
	KVS_STATUS_ERROR = 1,
	KVS_STATUS_NO_EXIST = 2,
	KVS_STATUS_EXIST = 3,
	KVS_STATUS_BADREQ = 4
}rsp_ret_status_e;

enum {
	KVS_CMD_START = 0,
	// array
	KVS_CMD_SET = KVS_CMD_START,
	KVS_CMD_GET,
	KVS_CMD_DEL,
	KVS_CMD_MOD,
	KVS_CMD_EXIST,
	// rbtree
	KVS_CMD_RSET,
	KVS_CMD_RGET,
	KVS_CMD_RDEL,
	KVS_CMD_RMOD,
	KVS_CMD_REXIST,
	// hash
	KVS_CMD_HSET,
	KVS_CMD_HGET,
	KVS_CMD_HDEL,
	KVS_CMD_HMOD,
	KVS_CMD_HEXIST,

	KVS_CMD_PSYNC,
	KVS_CMD_SAVE,
    
	KVS_CMD_COUNT,
};

typedef struct {
	uint8_t op;
	uint8_t status;
	uint32_t datalen;
	uint8_t *data;
} kvs_response_t;

int kvs_need(const uint8_t *p, const uint8_t *end, size_t n);
int kvs_read_u8(const uint8_t **pp, const uint8_t *end, uint8_t *out);
int kvs_read_u16(const uint8_t **pp, const uint8_t *end, uint16_t *out);
int kvs_read_u32(const uint8_t **pp, const uint8_t *end, uint32_t *out);

int kvs_write_u8(uint8_t **pp, const uint8_t *end, uint8_t v);
int kvs_write_u16(uint8_t **pp, const uint8_t *end, uint16_t v);
int kvs_write_u32(uint8_t **pp, const uint8_t *end, uint32_t v);

int getcmd(uint8_t op, const char *key, uint32_t key_len, const char *value, uint32_t value_len, uint8_t *buf);

int parse_response(const uint8_t *buf, int buflen, kvs_response_t *rsp);
void print_response(const char *cmd_name, const kvs_response_t *rsp);
int verify_response(const kvs_response_t *rsp, uint8_t expected_op, 
                    uint8_t expected_status, const char *expected_data, uint32_t expected_len);
                




typedef struct {
    uint8_t  buf[BATCH_SIZE];
    int      len;                 // 当前已写入的 batch 字节数
    int      cnt;                 // 当前 batch 里命令条数
    int      cmd_len[KVS_BATCH_MAX];
} kvs_batch_t;

static void kvs_batch_init(kvs_batch_t *b)
{
    b->len = 0;
    b->cnt = 0;
    memset(b->cmd_len, 0, sizeof(b->cmd_len));
}

/**
 * 用 getcmd() 生成单条命令，然后 append 到 batch buffer
 * 返回：0 成功，-1 失败（太多条 or buffer 不够）
 */
static int kvs_batch_add(kvs_batch_t *b, uint8_t op, const char *key, uint32_t key_len, const char *value, uint32_t value_len){
    if (b->cnt >= KVS_BATCH_MAX) return -1;
    uint8_t tmp[CMD_SIZE];
    int n = getcmd(op, key, key_len, value, value_len, tmp);   // 你提供的函数
    if (n <= 0) return -1;

    if (b->len + n > (int)sizeof(b->buf)) return -1;

    memcpy(b->buf + b->len, tmp, n);
    b->cmd_len[b->cnt] = n;
    b->cnt++;
    b->len += n;
    return 0;
}

/**
 * 一次性发送 batch
 * 返回：发送字节数，<0 表示失败
 */
static int kvs_batch_send(int fd, const kvs_batch_t *b)
{
    // printf("send : %d\n", b->len);
    return (int)send(fd, b->buf, b->len, 0);
}

/**
 * 一次 recv 收回所有响应，然后批量解析为 rsp 数组
 *
 * 返回：成功解析出的响应条数（期望是 b->cnt）
 */
static int kvs_batch_recv_parse(int fd,
                                const kvs_batch_t *b,
                                kvs_response_t *rsps,   // 输出数组，长度 >= b->cnt
                                uint8_t *recvbuf,
                                int recvbuf_cap)
{
    int parsed = 0;
    int used = 0;

    while(parsed < b->cnt){
        int nrecv = (int)recv(fd, recvbuf+used, recvbuf_cap, 0);
        if (nrecv <= 0) return -1;

        int off = 0;

        while (parsed < b->cnt) {
            int consumed = parse_response(recvbuf + used, nrecv - off, &rsps[parsed]);
            if (consumed <= 0) break;  // 不够解析/失败，简单处理：直接退出

            off += consumed;
            used+= consumed;
            parsed++;
        }
    }
    return parsed;
}