#include "kvstore.h"
#include "kvs_rw_tools.h"
#include "mem_pool/mem_pool.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include <unistd.h>
#include <arpa/inet.h>

#if ENABLE_ARRAY
extern kvs_array_t global_array;
#endif

#if ENABLE_RBTREE
extern kvs_rbtree_t global_rbtree;
#endif

#if ENABLE_HASH
extern kvs_hash_t global_hash;
#endif

#if MEMORY_SELECT_MALLOC == MEMORY_USE_MYMALLOC
extern mp_pool_t global_mempool;
#endif

#define KVS_SERVER_NOT_INIT	0
#define KVS_SERVER_MASETER 	1
#define KVS_SERVER_SLAVE	2
int kvs_server_role = KVS_SERVER_NOT_INIT;

int global_cmd_log_fd = -1;

const char *command[] = {
	"SET", "GET", "DEL", "MOD", "EXIST",
	"RSET", "RGET", "RDEL", "RMOD", "REXIST",
	"HSET", "HGET", "HDEL", "HMOD", "HEXIST"
};

const char *response[] = {

};

// return: -1 fail, 0 half, >0 consumed
int kvs_parse_one_cmd(const uint8_t *request, int request_length, kvs_req_t *req_out){
	if (!request || request_length <= 0 || !req_out) return -1;
	
	req_out->op = KVS_CMD_COUNT;
    req_out->argc = 0;
    req_out->args = NULL;

	const uint8_t *p = request;
    const uint8_t *end = request + (size_t)request_length;

	// OP + ARGC 
    if (kvs_need(p, end, 2)) {
        return 0; // NEED_MORE
    }

	uint8_t op = 0, argc = 0;
	if (kvs_read_u8(&p, end, &op) < 0) return -1;
	if (kvs_read_u8(&p, end, &argc) < 0) return -1;

	if (argc > KVS_MAX_ARGC) return -1;

	// 先扫描一遍确认整条命令数据都在 buffer 里
	const uint8_t *scan = p;
	uint32_t lens[KVS_MAX_ARGC];
	if (argc > 0) {
		for (uint8_t i = 0; i < argc; i++) {
			if (kvs_need(scan, end, 4)) {
				return 0; // NEED_MORE
			}
			uint32_t alen = 0;
			if (kvs_read_u32(&scan, end, &alen) < 0) return -1;

			// 防御：单个参数长度限制
			if (alen > KVS_MAX_ARGLEN) return -1;

			// 防御：scan + alen 越界 / 半包
			if (kvs_need(scan, end, (size_t)alen)) {
				return 0; // NEED_MORE
			}
			lens[i] = alen;
			scan += alen;
        }
	}

	size_t total_len = (size_t)(scan - request);
    if (total_len > KVS_MAX_CMD_BYTES) return -1;

	req_out->op = op;
    req_out->argc = argc;

	if (argc == 0) {
        return (int)total_len;
    }

	kvs_arg_t *args = (kvs_arg_t *)kvs_malloc((size_t)argc * sizeof(kvs_arg_t));
    if (!args) {
        kvs_free_request(req_out);
        return -1;
    }
	memset(args, 0, (size_t)argc * sizeof(kvs_arg_t));

	for (uint8_t i = 0; i < argc; i++) {
        uint32_t alen = 0;
        if (kvs_read_u32(&p, end, &alen) < 0) {
            kvs_free(args);
            kvs_free_request(req_out);
            return -1;
        }

        // alen 与 lens[i] 应当一致（扫描时读过），不一致说明解析器/输入异常
        if (alen != lens[i]) {
            kvs_free(args);
            kvs_free_request(req_out);
            return -1;
        }

        args[i].len = alen;
        args[i].data = p;     // 直接指向输入 buffer（零拷贝）
        p += alen;
    }

	
    req_out->args = args;

    return (int)(p - request);
}

void kvs_free_request(kvs_req_t *req) {
    if (!req) return;
    if (req->args) {
        kvs_free(req->args);
        req->args = NULL;
    }
    req->op = KVS_CMD_COUNT;
    req->argc = 0;
}

/**
 * 输入：req
 * 输出：rsp
 * 返回：-1 失败，参数错误，0 成功
 */
 int kvs_execute_one_cmd(const kvs_req_t *req, kvs_rsp_t *rsp_out) {
	if(!req || !rsp_out) return -1;
	rsp_out->op = req->op;
	rsp_out->status = KVS_STATUS_ERROR;
	rsp_out->data = NULL;
	rsp_out->dlen = 0;

	int argc = req->argc;
	kvs_cmd_t op = req->op;
	kvs_arg_t *argv = req->args;

	uint32_t key_len = 0;
	const void *key = NULL;
	uint32_t value_len = 0;
	const void *val = NULL;

	if(argc == 1){
		key_len = argv[0].len;
		key = argv[0].data;
	}else if(argc == 2){
		key_len = argv[0].len;
		key = argv[0].data;
		value_len = argv[1].len;
		val = argv[1].data;
	}

	// 基本参数校验（按你原有命令语义）
	switch (op) {
	case KVS_CMD_SET:
	case KVS_CMD_MOD:
	case KVS_CMD_RSET:
	case KVS_CMD_RMOD:
	case KVS_CMD_HSET:
	case KVS_CMD_HMOD:
		if (argc != 2 || !key || !val) { rsp_out->status = KVS_STATUS_BADREQ; return -1; }
		break;
	case KVS_CMD_GET:
	case KVS_CMD_DEL:
	case KVS_CMD_EXIST:
	case KVS_CMD_RGET:
	case KVS_CMD_RDEL:
	case KVS_CMD_REXIST:
	case KVS_CMD_HGET:
	case KVS_CMD_HDEL:
	case KVS_CMD_HEXIST:
	case KVS_CMD_PSYNC:
		if (argc != 1 || !key) { rsp_out->status = KVS_STATUS_BADREQ; return -1; }
		break;
	case KVS_CMD_SAVE:
		if(argc != 0) { rsp_out->status = KVS_STATUS_BADREQ; return -1; }
		break;
	default:
		rsp_out->status = KVS_STATUS_BADREQ;
		return -1;
	}

	int ret = 0;
	const char *result = NULL;

	switch (op) {
#if ENABLE_ARRAY
	case KVS_CMD_SET:
		ret = kvs_array_set_bin(&global_array, key, key_len, val, value_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_EXIST;
		return 0;

	case KVS_CMD_GET:
		result = kvs_array_get_bin(&global_array, key, key_len, &value_len);
		if (!result) { rsp_out->status = KVS_STATUS_NO_EXIST; return 0; }
		rsp_out->status = KVS_STATUS_OK;
		rsp_out->data = (uint8_t*)result;
		rsp_out->dlen = (uint32_t)value_len;
		return 0;

	case KVS_CMD_DEL:
		ret = kvs_array_del_bin(&global_array, key, key_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_NO_EXIST;
		return 0;

	case KVS_CMD_MOD:
		ret = kvs_array_mod_bin(&global_array, key, key_len, val, value_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_NO_EXIST;
		return 0;

	case KVS_CMD_EXIST:
		ret = kvs_array_exist_bin(&global_array, key, key_len);
		rsp_out->status = (ret == 0) ? KVS_STATUS_EXIST : KVS_STATUS_NO_EXIST;
		return 0;
#endif

#if ENABLE_RBTREE
	case KVS_CMD_RSET:
		ret = kvs_rbtree_set(&global_rbtree, key, key_len, val, value_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_EXIST;
		return 0;

	case KVS_CMD_RGET:
		result = kvs_rbtree_get(&global_rbtree, key, key_len, &value_len);
		if (!result) { rsp_out->status = KVS_STATUS_NO_EXIST; return 0; }
		rsp_out->status = KVS_STATUS_OK;
		rsp_out->data = (uint8_t*)result;
		rsp_out->dlen = (uint32_t)value_len;
		return 0;

	case KVS_CMD_RDEL:
		ret = kvs_rbtree_del(&global_rbtree, key, key_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_NO_EXIST;
		return 0;

	case KVS_CMD_RMOD:
		ret = kvs_rbtree_mod(&global_rbtree, key, key_len, val, value_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_NO_EXIST;
		return 0;

	case KVS_CMD_REXIST:
		ret = kvs_rbtree_exist(&global_rbtree, key, key_len);
		rsp_out->status = (ret == 0) ? KVS_STATUS_EXIST : KVS_STATUS_NO_EXIST;
		return 0;
#endif

#if ENABLE_HASH
	case KVS_CMD_HSET:
		ret = kvs_hash_set_bin(&global_hash, key, key_len, val, value_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_EXIST;
		return 0;

	case KVS_CMD_HGET:
		result = kvs_hash_get_bin(&global_hash, key, key_len, &value_len);
		if (!result) { rsp_out->status = KVS_STATUS_NO_EXIST; return 0; }
		rsp_out->status = KVS_STATUS_OK;
		rsp_out->data = (uint8_t*)result;
		rsp_out->dlen = (uint32_t)value_len;
		return 0;

	case KVS_CMD_HDEL:
		ret = kvs_hash_del_bin(&global_hash, key, key_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_NO_EXIST;
		return 0;

	case KVS_CMD_HMOD:
		ret = kvs_hash_mod_bin(&global_hash, key, key_len, val, value_len);
		if (ret < 0) rsp_out->status = KVS_STATUS_ERROR;
		else if (ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_NO_EXIST;
		return 0;

	case KVS_CMD_HEXIST:
		ret = kvs_hash_exist_bin(&global_hash, key, key_len);
		rsp_out->status = (ret == 0) ? KVS_STATUS_EXIST : KVS_STATUS_NO_EXIST;
		return 0;
#endif
	case KVS_CMD_SAVE:
		ret = kvs_save_to_file();
		if(ret == 0) rsp_out->status = KVS_STATUS_OK;
		else rsp_out->status = KVS_STATUS_ERROR;
		return 0;
	case KVS_CMD_PSYNC:
		rsp_out->op = req->op;
		rsp_out->status = KVS_STATUS_OK;
		return 0;
	default:
		rsp_out->status = KVS_STATUS_BADREQ;
		return -1;
	}

	return -1;
}

/**
 * 构建单条响应
 * 返回：-1 失败，>=0 响应长度
 */
int kvs_build_one_rsp(const kvs_rsp_t *results, uint8_t *response, size_t response_cap){
	if (!results || !response) return -1;

	const uint8_t *end = response + response_cap;
    uint8_t *p = response;

    // 计算所需长度：1 + 1 + 4 + dlen
    // 注意防止 size_t 溢出
    size_t need = 1u + 1u + 4u + (size_t)results->dlen;
    if (need > response_cap) return -1;

    if (kvs_write_u8(&p, end, (uint8_t)results->op) < 0) return -1;
    if (kvs_write_u8(&p, end, results->status) < 0) return -1;
    if (kvs_write_u32(&p, end, results->dlen) < 0) return -1;

    if (results->dlen > 0) {
        if (!results->data) return -1; // 有长度却没指针，视为错误
        if (kvs_need(p, end, (size_t)results->dlen) < 0) return -1;
        memcpy(p, results->data, results->dlen);
        p += results->dlen;
    }

    return (int)(p - response);
}

int kvs_save_to_file(){
	int ret = 0;
	int rc = 0;
	#if ENABLE_ARRAY
	rc = kvs_array_save(&global_array, KVS_ARRAY_FILE);
	if(rc < 0){
		printf("kvs_engine_array save error\n");
		ret = -1;
	}
	#endif

	#if ENABLE_RBTREE
	rc = kvs_rbtree_save(&global_rbtree, KVS_RBTREE_FILE);
	if(rc < 0){
		printf("kvs_engine_rbtree save error\n");
		ret = -1;
	}
	#endif

	#if ENABLE_HASH
	rc = kvs_hash_save(&global_hash, KVS_HASH_FILE);
	if(rc < 0){
		printf("kvs_engine_hash save error\n");
		ret = -1;
	}
	#endif

	ksv_clear_log(global_cmd_log_fd);

	return ret;
}

int is_update_cmd(kvs_cmd_t op){
	if(op == KVS_CMD_SET || op == KVS_CMD_RSET || op == KVS_CMD_HSET
		|| op == KVS_CMD_MOD || op == KVS_CMD_RMOD || op == KVS_CMD_HMOD
		|| op == KVS_CMD_DEL || op == KVS_CMD_RDEL || op == KVS_CMD_HDEL){
		return 1;
	}
	return 0;
}

/**
 * input 	: request request_length
 * output	: response response_length
 * return	: -1 error, =0 半包, 1 成功
 */


// int kvs_protocol(char *request, int request_length, char *response, int *response_length){
int kvs_protocol(struct conn* conn){
	if (!conn) return -1;
	char *request = conn->rbuffer;
	int request_length = conn->rlength;
	char *response = conn->wbuffer;
	int *response_length = &conn->wlength;

	if (!request || request_length <= 0 || !response || !response_length) return -1;
	int consumed = 0;
	int out_len = 0;

	static int i = 0;
	while(consumed < request_length ){
		if(i > 33){
			i = i+1;
			i = i-1;
		}
		if(i == 47) i = 0;
		++i;

		kvs_req_t req;
		memset(&req, 0, sizeof(kvs_req_t));

		const uint8_t *p = request+consumed;
		int remain = request_length - consumed;

		int len = kvs_parse_one_cmd(p, remain, &req);
		if(len < 0){
		// 解析失败
			kvs_free_request(&req);
			*response_length = out_len;
			return -1;
		}
		else if(len == 0){
		// 半包
			kvs_free_request(&req);
			break;
		}
		
		kvs_rsp_t rsp;
		memset(&rsp, 0, sizeof(kvs_rsp_t));

		// 执行失败
		if (kvs_execute_one_cmd(&req, &rsp) < 0){
			kvs_free_request(&req);
            *response_length = out_len;
			return -1;
		}else{
// 执行成功，在这里保存到日志中。
			if(rsp.status == KVS_STATUS_OK){
				if(is_update_cmd(req.op)){
					kvs_save_cmd_to_logfile(p, len, global_cmd_log_fd);
				}
			}
		}

		if(req.op == KVS_CMD_PSYNC){
			build_thread_to_sync(req.args->data, conn);
		}

		int resp_len = kvs_build_one_rsp(&rsp, (uint8_t *)response+out_len, KVS_MAX_RESPONSE-out_len);
		// 构建响应 <0 构建失败
		kvs_free_request(&req);
		if (resp_len < 0) {
            *response_length = out_len;
			return -1;
		}

		out_len += resp_len;
		consumed += len;
	}

	// slave 暂时不需要回报，或者回一个new_offset
	if(conn->is_from_master){
		conn->wlength = 0;
		return consumed;
	}
    *response_length = out_len;
	return consumed;
}

extern void sync_wakeup(int fd);
static int g_slavefd = -1;
static uint64_t g_offset = 0;

static void *sync_thread_main(void *arg) {
    struct conn *conn = (struct conn*) arg;

	int logfd = open(KVS_CMD_LOG_FILE, O_RDONLY);
    if (logfd < 0) {
        printf("open replaylog failed: %s\n", strerror(errno));
        return NULL;
    }

	pthread_mutex_lock(&conn->g_sync_lock);
    uint64_t off = g_offset;
    pthread_mutex_unlock(&conn->g_sync_lock);

	 while (1) {

        // 单槽位：等 reactor 发完再填
        pthread_mutex_lock(&conn->g_sync_lock);
        int busy = (conn->wlength > 0);
        pthread_mutex_unlock(&conn->g_sync_lock);
        if (busy) { usleep(10 * 1000); continue; }

        size_t filled = 0;
        int records = 0;

        // 试图攒一批
        while (filled < (size_t)KVS_MAX_RESPONSE && records < 128) {

            // 读 len 头
            uint32_t nlen = 0;
            ssize_t r = pread(logfd, &nlen, sizeof(nlen), (off_t)off);

            if (r == 0) {
                // EOF：文件当前没更多数据
                break;
            }
            if (r < 0) {
                if (errno == EINTR) continue;
                printf("pread len error: %s\n", strerror(errno));
                close(logfd);
                return NULL;
            }
            if (r < (ssize_t)sizeof(nlen)) {
                // 半截 len：writer 还没写完头
                break;
            }

            uint32_t len = ntohl(nlen);
			if(len <= 0) {
				printf("sync error\n");
			}

            // 这一条放不进本批次，就先发已有的
            if (filled + len > (size_t)KVS_MAX_RESPONSE) {
                break;
            }

            // 读 payload(cmd)
            ssize_t pr = pread(logfd, conn->wbuffer + filled, len,
                               (off_t)(off + sizeof(nlen)));

            if (pr == 0) {
                // payload 还没写到
                break;
            }
            if (pr < 0) {
                if (errno == EINTR) continue;
                printf("pread payload error: %s\n", strerror(errno));
                close(logfd);
                return NULL;
            }
            if (pr < (ssize_t)len) {
                // 半截 payload：writer 还没写完这一条
                break;
            }

            // 成功拿到一条完整记录：推进
            off += sizeof(nlen) + (uint64_t)len;
            filled += (size_t)len;
            records++;

        }

        if (filled > 0) {
            // 提交给 reactor 发送
            pthread_mutex_lock(&conn->g_sync_lock);
            conn->wlength = (int)filled;
            g_offset = off; 
            pthread_mutex_unlock(&conn->g_sync_lock);

            // 唤醒 reactor 发
            sync_wakeup(conn->fd); // 或 g_slavefd
            continue;
        }

        // 没攒到任何完整记录：说明真到末尾/半条记录，等一会儿
        usleep(10*1000);
    }

    close(logfd);
    return NULL;
}

void build_thread_to_sync(const uint8_t *offset, struct conn* conn){
	uint64_t off64 = 0;
    memcpy(&off64, offset, 8);
	
	pthread_mutex_lock(&conn->g_sync_lock);
	g_slavefd = conn->fd;
	g_offset = (uint64_t)off64;

	conn->wlength = 0;
	pthread_mutex_unlock(&conn->g_sync_lock);

	pthread_t tid;

	int rc = pthread_create(&tid, NULL, sync_thread_main, conn);
    if (rc != 0) {
        printf("pthread_create failed: %s\n", strerror(rc));
        return;
    }

    pthread_detach(tid);
}

int init_kvengine(void) {

#if ENABLE_ARRAY
	memset(&global_array, 0, sizeof(kvs_array_t));
	kvs_array_create(&global_array);

	kvs_array_load(&global_array, KVS_ARRAY_FILE);
#endif

#if ENABLE_RBTREE
	memset(&global_rbtree, 0, sizeof(kvs_rbtree_t));
	kvs_rbtree_create(&global_rbtree);

	kvs_rbtree_load(&global_rbtree, KVS_RBTREE_FILE);
#endif

#if ENABLE_HASH
	memset(&global_hash, 0, sizeof(kvs_hash_t));
	kvs_hash_create(&global_hash);
	
	kvs_hash_load(&global_hash, KVS_HASH_FILE);
#endif

	init_cmd_log(KVS_CMD_LOG_FILE, &global_cmd_log_fd);
	kvs_replay_log(KVS_CMD_LOG_FILE, global_cmd_log_fd);

	return 0;
}

void dest_kvengine(void) {
#if ENABLE_ARRAY
	kvs_array_destroy(&global_array);
#endif
#if ENABLE_RBTREE
	kvs_rbtree_destroy(&global_rbtree);
#endif
#if ENABLE_HASH
	kvs_hash_destroy(&global_hash);
#endif

	destroy_cmd_log(global_cmd_log_fd);
}

void init_memory_pool(void){
#if MEMORY_SELECT_MALLOC == MEMORY_USE_MYMALLOC
	mp_init(&global_mempool);
#endif
}

void dest_memory_pool(void){
#if MEMORY_SELECT_MALLOC == MEMORY_USE_MYMALLOC
	mp_destroy(&global_mempool);
#endif 
}

/** 
 * ./ksvtore [role] [port]
 * ./kvstore master 8888 
 * 
 * ./ksvtore [role] [port] [masterip] [masterport]
 * ./kvstore slave  7000 192.168.10.129 8888
 */ 
int main(int argc, char *argv[]) {

	if (argc < 3) return -1;
	
	char *role = argv[1];
	int port = atoi(argv[2]);
	
	char *master_ip = NULL;
	int master_port = -1;

	if(strcmp(role, "master") == 0){
		kvs_server_role = KVS_SERVER_SLAVE;
	}else if(strcmp(role, "slave") == 0){
		kvs_server_role = KVS_SERVER_MASETER;
		if(argc < 5) return -1;
		master_ip = argv[3];
		master_port = atoi(argv[4]);

	}

	init_memory_pool();
	init_kvengine();
	
	
#if (NETWORK_SELECT == NETWORK_REACTOR)
	reactor_start(port, kvs_protocol, master_ip, master_port);  //
#elif (NETWORK_SELECT == NETWORK_PROACTOR)
	proactor_start(port, kvs_protocol);
#elif (NETWORK_SELECT == NETWORK_NTYCO)
	ntyco_start(port, kvs_protocol);
#endif

	dest_kvengine();
	dest_memory_pool();
}