/*
 * Source file for entry point and initialization.
 * 
 * CAR (Cool ARM Ripoff) copyright (c) 2026 David J Goeke. All rights reserved.
 * Unauthorized (re)distribution is prohibited.
*/

#include <stdio.h>
#include <stdlib.h>

#include "include/defs.h"

static long get_file_size(FILE *fp)
{
    long current = ftell(fp);

    fseek(fp, 0, SEEK_END);
    long size = ftell(fp);

    fseek(fp, current, SEEK_SET);

    return size;
}

int main(int argc, char** argv)
{
	printf("CAR (Cool ARM Ripoff) copyright (c) 2026 David J Goeke. All rights reserved.\n\n");
	
	pstate_t* state = malloc(sizeof(pstate_t));
	
	if (!state)
	{
		printf("Error: malloc failed.\n");
		return -1;
	}
	
	if (argc < 1)
	{
		printf("Error: no input file specified.\n");
		return -1;
	}
	
	FILE* f = fopen(argv[1], "rb");
	
	if (!f)
	{
		printf("Error: failed to open file %s.\n", argv[1]);
		return -1;
	}
	
	uint8_t* data = malloc(get_file_size(f));
	
	if (!data)
	{
		printf("Error: malloc failed.\n");
		free(state);
		return -1;
	}
	
	size_t read = fread(data, 1, get_file_size(f), f);
	
	size_t words = read / sizeof(uint32_t);
	
	if (read % sizeof(uint32_t) != 0)
	{
		fprintf(stderr, "Error: file size (%zu bytes) is not a multiple of 4.\n", read);
		free(data);
		free(state);
		fclose(f);
		return -1;
	}
	
	
	state->memory_size = words; // Just to be safe, use the number of bytes read instead of what get_file_size told us
	state->memory = (uint32_t*) data;
	
	state->flags = 0;
	state->pc = 0; // TODO: we should load ELF files or some other format so we can start somewhere other than address 0 (and so we can have bss)
	// We could set sp, but let's let software do that
	
	for (int k = 0; k < words; k++)
	{
		state->memory[k] = __builtin_bswap32(state->memory[k]);
	}
	
	int j = processor_start(state);
	
	if (j != 0)
	{
		// An error occured, though a message already has been printed, so for now do nothing.
	}
	
	free(data); // or would could do free(state->memory), shouldn't matter
	free(state);
	
	return 0;
}