#include "test_client.h"
#include <stdio.h>
#include <errno.h>
#include <unistd.h>

int kvs_need(const uint8_t *p, const uint8_t *end, size_t n) {
	return (p + n <= end) ? 0 : -1;
}

// 注意u8类型不需要ntoh或者hton
int kvs_read_u8(const uint8_t **pp, const uint8_t *end, uint8_t *out) {
	const uint8_t *p = *pp;
	if (kvs_need(p, end, 1) < 0) return -1;
	*out = *p;
	*pp = p + 1;
	return 0;
}

int kvs_read_u16(const uint8_t **pp, const uint8_t *end, uint16_t *out) {
	const uint8_t *p = *pp;
	if (kvs_need(p, end, 2) < 0) return -1;
	uint16_t v;
	memcpy(&v, p, 2);
	*out = ntohs(v);
	*pp = p + 2;
	return 0;
}

int kvs_read_u32(const uint8_t **pp, const uint8_t *end, uint32_t *out) {
	const uint8_t *p = *pp;
	if (kvs_need(p, end, 4) < 0) return -1;
	uint32_t v;
	memcpy(&v, p, 4);
	*out = ntohl(v);
	*pp = p + 4;
	return 0;
}

int kvs_write_u8(uint8_t **pp, const uint8_t *end, uint8_t v) {
	uint8_t *p = *pp;
	if (kvs_need(p, end, 1) < 0) return -1;
	*p = v;
	*pp = p + 1;
	return 0;
}

int kvs_write_u16(uint8_t **pp, const uint8_t *end, uint16_t v) {
	uint8_t *p = *pp;
	if (kvs_need(p, end, 2) < 0) return -1;
	uint16_t be = htons(v);
	memcpy(p, &be, 2);
	*pp = p + 2;
	return 0;
}

int kvs_write_u32(uint8_t **pp, const uint8_t *end, uint32_t v) {
	uint8_t *p = *pp;
	if (kvs_need(p, end, 4) < 0) return -1;
	uint32_t be = htonl(v);
	memcpy(p, &be, 4);
	*pp = p + 4;
	return 0;
}



int getcmd(uint8_t op, const char *key, const char *value, uint8_t *buf){
	if(!buf) return -1;
	uint8_t *end = buf + CMD_SIZE;
	uint8_t *p = buf;
	uint8_t argc = (key == NULL)?0:1;
	argc += (value == NULL)?0:1;


	if (kvs_write_u8(&p, end, op) < 0) return -1;
	if (kvs_write_u8(&p, end, argc) < 0) return -1;
	

	// 写入 key
	if(key){
		int keylen = strlen(key);
		if (kvs_write_u32(&p, end, keylen) < 0) return -1;
		if (kvs_need(p, end, keylen) < 0) return -1;
		if (keylen > 0) {
			memcpy(p, key, keylen);
			p += keylen;
		}
	}

	if(value){
		int vallen = strlen(value);
		if (kvs_write_u32(&p, end, vallen) < 0) return -1;
		if (kvs_need(p, end, vallen) < 0) return -1;
		if (vallen > 0) {
			memcpy(p, value, vallen);
			p += vallen;
		}
	}

	return (p - buf);
}

int parse_response(const uint8_t *buf, int buflen, kvs_response_t *rsp) {
	const uint8_t *p = buf;
	const uint8_t *end = buf + buflen;
	
	// 读取 OP
	if (kvs_read_u8(&p, end, &rsp->op) < 0) {
		fprintf(stderr, "Failed to read op\n");
		return -1;
	}
	
	// 读取 status
	if (kvs_read_u8(&p, end, &rsp->status) < 0) {
		fprintf(stderr, "Failed to read status\n");
		return -1;
	}
	
	// 读取 datalen
	if (kvs_read_u32(&p, end, &rsp->datalen) < 0) {
		fprintf(stderr, "Failed to read datalen\n");
		return -1;
	}
	
	// 检查数据长度
	if (kvs_need(p, end, rsp->datalen) < 0) {
		fprintf(stderr, "Data length mismatch: expected %u bytes, but only %ld available\n", 
				rsp->datalen, end - p);
		return -1;
	}
	
	// 指向数据部分
	rsp->data = (uint8_t *)p;
	
	return (p - buf) + rsp->datalen;
}


void print_response(const char *cmd_name, const kvs_response_t *rsp) {
	printf("\n=== %s Response ===\n", cmd_name);
	printf("OP: %u\n", rsp->op);
	printf("Status: %u ", rsp->status);
	
	switch (rsp->status) {
		case KVS_STATUS_OK:
			printf("(OK)\n");
			break;
		case KVS_STATUS_ERROR:
			printf("(ERROR)\n");
			break;
		case KVS_STATUS_NO_EXIST:
			printf("(NO_EXIST)\n");
			break;
		case KVS_STATUS_EXIST:
			printf("(EXISTS)\n");
			break;
		default:
			printf("(UNKNOWN)\n");
			break;
	}
	
	printf("Data Length: %u\n", rsp->datalen);
	
	if (rsp->datalen > 0 && rsp->data != NULL) {
		printf("Data: ");
		// 尝试以字符串形式打印（如果是可打印字符）
		int is_printable = 1;
		for (uint32_t i = 0; i < rsp->datalen; i++) {
			if (rsp->data[i] < 32 || rsp->data[i] > 126) {
				is_printable = 0;
				break;
			}
		}
		
		if (is_printable) {
			printf("\"");
			for (uint32_t i = 0; i < rsp->datalen; i++) {
				printf("%c", rsp->data[i]);
			}
			printf("\"\n");
		} else {
			// 以十六进制打印
			printf("0x");
			for (uint32_t i = 0; i < rsp->datalen; i++) {
				printf("%02x", rsp->data[i]);
			}
			printf("\n");
		}
	} else {
		printf("Data: (empty)\n");
	}
	printf("==================\n");
}

int verify_response(const kvs_response_t *rsp, uint8_t expected_op, 
                    uint8_t expected_status, const char *expected_data) {
	if (rsp->op != expected_op) {
		printf("❌ OP mismatch: expected %u, got %u\n", expected_op, rsp->op);
		return 0;
	}
	
	if (rsp->status != expected_status) {
		printf("❌ Status mismatch: expected %u, got %u\n", expected_status, rsp->status);
		return 0;
	}
	
	if (expected_data != NULL) {
		uint32_t expected_len = strlen(expected_data);
		if (rsp->datalen != expected_len) {
			printf("❌ Data length mismatch: expected %u, got %u\n", expected_len, rsp->datalen);
			return 0;
		}
		
		if (memcmp(rsp->data, expected_data, expected_len) != 0) {
			printf("❌ Data content mismatch\n");
			return 0;
		}
	}
	
	return 1;
}