#include "kvs_dump.h"
#include "kvs_rw_tools.h"
#include "memory/alloc_dispatch.h"
#include "kvs_protocol_resp.h"
#include "diskuring/diskuring.h"
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>

int global_oplog_fd = -1;
static off_t g_log_off = -1;

int init_cmd_log(const char *file, int *logfd){
	if(!file) return -1;
	int fd = open(file, O_RDWR | O_CREAT , 0644);
	if(fd < 0) return -2;


    g_log_off = lseek(fd, 0, SEEK_END);
	*logfd = fd;
	return 0;
}

int destroy_cmd_log(int logfd){
    fsync(logfd);
	close(logfd);
    global_oplog_fd = -1;
	return 0;
}

int kvs_oplog_append(const uint8_t *cmd, size_t len, int logfd){
	if (logfd < 0 || !cmd || len == 0) return -1;
    if (len > UINT32_MAX) return -2;


    uint32_t nlen = htonl((uint32_t)len);

    void *bufs[2];
    size_t lens[2];

    bufs[0] = (void *)&nlen;
    lens[0] = sizeof(nlen);

    bufs[1] = (void *)cmd;
    lens[1] = len;

    size_t total = sizeof(nlen) + len;

    off_t myoff = g_log_off;
    g_log_off += (off_t)total;

    task_t *t = submit_write(&global_uring_ctx, logfd, bufs, lens, 2, myoff);
    if (!t) {
        return -4;
    }

    // task_wait(t);
    // task_destroy(t);

	return 0;
}

int	kvs_replay_log(int logfd){
	if (logfd < 0) return -1;

    if (lseek(logfd, 0, SEEK_SET) < 0) {
        return -1;
    }

    for (;;) {
        uint32_t nlen = 0;

        int hr = read_full(logfd, &nlen, sizeof(nlen));
        if (hr == 0) break;             /* EOF：正常结束 */
        if (hr < 0) { return -2; }      /* 半截头 */

        uint32_t len = ntohl(nlen);
        if (len == 0) { return -3; }

        uint8_t *cmd_bytes = (uint8_t *)kvs_malloc(len);
        if (!cmd_bytes ) { return -5; }

        int pr = read_full(logfd, cmd_bytes, len);
        if (pr <= 0) {                  /* 半截 payload */
            kvs_free(cmd_bytes );
            return -6;
        }

        /* -------- RESP parse -------- */
        resp_cmd_t cmd;
        memset(&cmd, 0, sizeof(cmd));

        int clen = resp_parse_one_cmd(cmd_bytes, (int)len, &cmd);

        if (clen <= 0 || clen != (int)len) {
            /* clen==0: need more data，但日志记录必须是一条完整命令，所以视为坏日志 */
            kvs_free(cmd_bytes);
            return -7;
        }

        /* -------- execute -------- */
        resp_value_t outvalue;
        memset(&outvalue, 0, sizeof(outvalue));

        int dr = resp_dispatch(&cmd, &outvalue);
        if (dr < 0) {
            kvs_free(cmd_bytes);
            return -8;
        }

        /* 注意：
         * outv 可能引用存储内存，但我们不 build response，因此无需处理。
         * cmd_bytes 可以释放，因为 cmd slice 指向 cmd_bytes，仅在 dispatch 期间使用。 
         * */
        kvs_free(cmd_bytes);
    }

    g_log_off = lseek(logfd, 0, SEEK_CUR);

    return 0;
}

/**
 * clear log file not close
 */
int ksv_clear_log(int logfd){
	if(logfd < 0) return -1;
	ftruncate(logfd, 0);
	lseek(logfd, 0, SEEK_SET);
    g_log_off = 0;
	return 0;
}