#include <stdio.h>
#include <stdbool.h>

bool CheckArgumentSet(int argc, char* argv[]);
void EchoBox();
void FileHandler(int argc, char* argv[]);
bool IsFileReadable(FILE* currentFile, char* fileName);
void PrintChosenFile(FILE* currentFile);
void PrintChosenFileNumbered(FILE* currentFile);
int lineNumber = 1;

int main(int argc, char* argv[])
{
    if (argc == 1)
        EchoBox();
    if (argc > 1)
        FileHandler(argc, argv);
    return 0;
}

// Check if line number argument is set
bool CheckArgumentSet(int argc, char* argv[])
{
    char argumentHyphen = '-';
    char argumentLetter = 'b';
    for (int i = 1; i < argc; i++)
    {
        if ((*(argv[i]) == argumentHyphen) && (*(argv[i]+1) == argumentLetter))
        {
            return 1;
        }
    }
    return 0;
}

// Handling Cat without arguments
void EchoBox()
{
    char inputText[100];
    while (true)
    {
        scanf("%s", inputText);
        printf("%s\n", inputText);    
    }
}

// Base function for passing work to other functions
void FileHandler(int argc, char* argv[])
{
    FILE* currentFile;
    bool argumentEnabled = CheckArgumentSet(argc, argv);
    for (int i = 1; i < argc; i++)
    {
        if ((currentFile = fopen(argv[i], "r")) == NULL)
        {
            if (!argumentEnabled)
                fprintf(stderr, "cat: %s: No such file or directory\n", argv[i]);
            continue;
        }
        if (argumentEnabled)
            PrintChosenFileNumbered(currentFile);
        if (!argumentEnabled)
            PrintChosenFile(currentFile);
        fclose(currentFile);
    }
}

// Print text of a chosen file without line numbers
void PrintChosenFile(FILE* currentFile)
{
    char buffer[4];
    while (fgets(buffer, sizeof(buffer), currentFile))
    {
        printf("%s", buffer);
    }
}

// Print text of a chosen file with line numbers
void PrintChosenFileNumbered(FILE* currentFile)
{
    bool isNewLine = 0;
    char buffer[2];
    printf("    %2d ", lineNumber);
    lineNumber = lineNumber + 1;
    while (fgets(buffer, sizeof(buffer), currentFile))
    {
        if (isNewLine && (buffer[0] == '\n'))
        {
            printf("%s", buffer);
            continue;
        }
        if (isNewLine && (buffer[0] != '\n'))
        {
            printf("    %2d %s", lineNumber, buffer);
            lineNumber = lineNumber + 1;
            isNewLine = 0;
            continue;
        }
        if (!isNewLine && (buffer[0] == '\n'))
        {
            isNewLine = 1;
            printf("%s", buffer);
            continue;
        }
        printf("%s",  buffer);
    }
}

// Check if file is readable
// Return true if readable, and false if not readable
// Todo: Fix function, breaks code if used
bool IsFileReadable(FILE* currentFile, char* fileName)
{
    if((currentFile = fopen(fileName, "r")) == NULL)
    {
        fprintf(stderr, "cat: %s: No such file or directory\n", fileName);
        return 0;
    }
    return 1;
}