#ifndef __cosmopolitan
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#ifdef _WIN32
	#include <windows.h>
#else
	#include <sys/mman.h>
#endif
#endif
#include "base14.h"

#ifdef __cosmopolitan
#define get_file_size(filepath) ((off_t)GetFileSize(filepath))
#else
static off_t get_file_size(const char* filepath) {
    struct stat statbuf;
    return stat(filepath, &statbuf)?-1:statbuf.st_size;
}
#endif

char encbuf[BUFSIZ*1024/7*7];
char decbuf[BUFSIZ*1024/8*8+2];

void encode_file(const char* input, const char* output) {
	off_t inputsize = get_file_size(input);
	if(inputsize <= 0) {
		perror("Get file size error: ");
		return;
	}
	if(inputsize > (1u<<31)-1) {
		puts("Input file too big!");
		return;
	}
	FILE* fpo = NULL;
	fpo = fopen(output, "wb");
	if(!fpo) {
		perror("Fopen output file error: ");
		return;
	}
	if(inputsize > BUFSIZ*1024) { // big file, use encbuf & fread
		inputsize = BUFSIZ*1024/7*7;
		#ifdef _WIN32
	}
		#endif
		FILE* fp = NULL;
		fp = fopen(input, "rb");
		if(!fp) {
			perror("Fopen input file error: ");
			return;
		}
		
		int outputsize = encode_len(inputsize)+16;
		size_t cnt = 0;
		fputc(0xFE, fpo);
		fputc(0xFF, fpo);
		while((cnt = fread(encbuf, sizeof(char), inputsize, fp))) {
			int n = encode(encbuf, cnt, decbuf, outputsize);
			if(fwrite(decbuf, n, 1, fpo) <= 0) {
				perror("Write file error: ");
				return;
			}
		}
		/* 由操作系统负责释放资源
			fclose(fpo);
			fclose(fp);
		以缩短程序运行时间 */
	#ifndef _WIN32
	} else { // small file, use mmap & fwrite
		int fd = open(input, O_RDONLY);
		if(fd <= 0) {
			perror("Open input file error: ");
			return;
		}
		char *input_file = mmap(NULL, (size_t)inputsize, PROT_READ, MAP_PRIVATE, fd, 0);
		if(input_file == MAP_FAILED) {
			perror("Map input file error: ");
			return;
		}
		int outputsize = encode_len(inputsize)+16;
		fputc(0xFE, fpo);
		fputc(0xFF, fpo);
		int n = encode(input_file, (int)inputsize, decbuf, outputsize);
		if(fwrite(decbuf, n, 1, fpo) <= 0) {
			perror("Write file error: ");
			return;
		}
		munmap(input_file, (size_t)inputsize);
		/* 由操作系统负责释放资源
			fclose(fpo);
			close(fd);
		以缩短程序运行时间 */	
	}
	#endif
}

#define rm_head(fp) {\
	int ch = fgetc(fp);\
	if(ch == 0xFE) fgetc(fp);\
	else rewind(fp);\
}

#define skip_offset(input_file) ((input_file[0]==(char)0xFE)?2:0)

static int is_next_end(FILE* fp) {
	int ch = fgetc(fp);
	if(ch == '=') return fgetc(fp);
	ungetc(ch, fp);
	return 0;
}

void decode_file(const char* input, const char* output) {
	off_t inputsize = get_file_size(input);
	if(inputsize <= 0) {
		perror("Get file size error: ");
		return;
	}
	if(inputsize > (1u<<31)-1) {
		puts("Input file too big!");
		return;
	}
	FILE* fpo = NULL;
	fpo = fopen(output, "wb");
	if(!fpo) {
		perror("Fopen output file error: ");
		return;
	}
	if(inputsize > BUFSIZ*1024) { // big file, use decbuf & fread
		inputsize = BUFSIZ*1024/8*8;
		#ifdef _WIN32
	}
		#endif
		FILE* fp = NULL;
		fp = fopen(input, "rb");
		if(!fp) {
			perror("Fopen input file error: ");
			return;
		}
		int outputsize = decode_len(inputsize, 0)+16;
		int cnt = 0;
		int end = 0;
		rm_head(fp);
		while((cnt = fread(decbuf, sizeof(char), inputsize, fp))) {
			if((end = is_next_end(fp))) {
				decbuf[cnt++] = '=';
				decbuf[cnt++] = end;
			}
			if(fwrite(encbuf, decode(decbuf, cnt, encbuf, outputsize), 1, fpo) <= 0) {
				perror("Write file error: ");
				return;
			}
		}
		/* 由操作系统负责释放资源
			fclose(fpo);
			fclose(fp);
		以缩短程序运行时间 */
	#ifndef _WIN32
	} else { // small file, use mmap & fwrite
		int fd = open(input, O_RDONLY);
		if(fd <= 0) {
			perror("Open input file error: ");
			return;
		}
		char *input_file = mmap(NULL, (size_t)inputsize, PROT_READ, MAP_PRIVATE, fd, 0);
		if(input_file == MAP_FAILED) {
			perror("Map input file error: ");
			return;
		}
		int outputsize = decode_len(inputsize, 0)+16;
		int off = skip_offset(input_file);
		if(fwrite(encbuf, decode(input_file+off, inputsize-off, encbuf, outputsize), 1, fpo) <= 0) {
			perror("Write file error: ");
			return;
		}
		munmap(input_file, (size_t)inputsize);
		/* 由操作系统负责释放资源
			fclose(fpo);
			close(fd);
		以缩短程序运行时间 */	
	}
	#endif
}

#ifndef _WIN32
unsigned long get_start_ms() {
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    return (ts.tv_sec * 1000 + ts.tv_nsec / 1000000);
}
#endif

#define CHOICE argv[1][1]
int main(int argc, char** argv) {
	if(argc != 4) {
        fputs("Usage: -[e|d] <inputfile> <outputfile>\n", stderr);
        fputs("\t-e encode\n", stderr);
        fputs("\t-d decode\n", stderr);
        exit(EXIT_FAILURE);
    }
	#ifdef _WIN32
		clock_t t = clock();
	#else
		unsigned long t = get_start_ms();
	#endif
	switch(CHOICE) {
		case 'e': encode_file(argv[2], argv[3]); break;
		case 'd': decode_file(argv[2], argv[3]); break;
		default: break;
	}
	#ifdef _WIN32
		printf("spend time: %lums\n", clock() - t);
	#else
		printf("spend time: %lums\n", get_start_ms() - t);
	#endif
    return 0;
}