#include <string.h>
#include "global.h"
#include "fileio.h"

#define MAX_ASM_LINE_LENGTH 300

int isValidFileFormat(char filename[], char expectedExtension[]){
    char *pointLoc = strrchr(filename, '.');

    if(pointLoc != NULL){
        if(strcmp(pointLoc, expectedExtension)==0){
            return(1);
        }
    }
    return(0);
}

void writeBinaryFile(word instrs[], char outputFile[], int numInstrs) {
    FILE *fp = fopen(outputFile, "wb");
    if (fp == NULL) {
        fprintf(stderr, "Error: Could not open file %s\n", outputFile);
        exit(EXIT_FAILURE);
    }
    
    fwrite(instrs, sizeof(word), numInstrs, fp);
    fclose(fp);
}

int countLines(char *filename) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        fprintf(stderr, "Error: Could not read file %s\n", filename);
        exit(EXIT_FAILURE);
    }

    int count = 0;
    char c;
    char prevC = '\n';

    while ((c = fgetc(file)) != EOF) {
        if (c == '\n' && prevC != '\n') {
            count++;
        }
        prevC = c;
    }

    return count;
}

char **readAssemblyFile(char filename[], int lineCount) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        fprintf(stderr, "Error: Could not read file %s\n", filename);
        exit(EXIT_FAILURE);
    }

    char **lines = malloc(sizeof(char *) * lineCount + 1);
    if (lines == NULL) {
        fprintf(stderr, "Error: Could not allocate memory to store the assembly lines");
        exit(EXIT_FAILURE);
    }

    rewind(fp); // Back to the beginning of the file.

    char buffer[MAX_ASM_LINE_LENGTH];
    int currentLine = 0;
    
    while (fgets(buffer, MAX_ASM_LINE_LENGTH, fp) != NULL) {
        if (buffer[strlen(buffer) - 1] != '\n') {
            // It was actually longer than the maximum.
            // NOTE: I believe this must mean that this is a malformed line, so throw an error.
            fprintf(stderr, "Error: Line %d in the file %s is too long\n", currentLine, filename);
            exit(EXIT_FAILURE);
        }

        if (*buffer == '\n') {
            // Skip empty lines.
            continue;
        }

        lines[currentLine] = malloc(strlen(buffer) + 1);
        if (lines[currentLine] == NULL) {
            fprintf(stderr, "Error: Could not allocate memory to store the assembly line");
            exit(EXIT_FAILURE);
        }

        strcpy(lines[currentLine], buffer);
        currentLine++;
    }
    
    if (ferror(fp)) {
        fprintf(stderr, "Error: Could not read file %s", filename);
        exit(EXIT_FAILURE);
    }

    return lines;
}