#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>

#define MAX_SIZE 1024
#define HISTORY_SIZE 10

// Global variable for termios
struct termios orig_termios;

// Terminal input helpers
void EnableRawMode(struct termios* orig_termios) {
    struct termios raw = *orig_termios;
    raw.c_lflag &= ~(ECHO | ICANON); // Disable echo and canonical mode
    tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
}

void DisableRawMode(struct termios* orig_termios) {
    tcsetattr(STDIN_FILENO, TCSAFLUSH, orig_termios);
}

// Wrapper function to pass DisableRawMode with argument
void DisableRawModeWrapper() {
    DisableRawMode(&orig_termios);
}

int LogCommandHistory(char* buf, char** command_log, int* n) {
    int index = *n % HISTORY_SIZE;
    int prev_index = (*n == 0) ? HISTORY_SIZE - 1 : (*n - 1) % HISTORY_SIZE;

    if (command_log[prev_index] != NULL && strcmp(buf, command_log[prev_index]) == 0) {
        return 0;
    }
    if (command_log[index] != NULL) {
        free(command_log[index]);
    }

    command_log[index] = strdup(buf);
    (*n)++;

    return 0;
}


void FreeCommandHistory(char** command_log, int n) {
    for (int i = 0; i < n; i++) {
        free(command_log[i]);
    }
}

// Get input with arrow key navigation
void GetInputWithHistory(char* buf, char** command_log, int n) {
    int index = n % HISTORY_SIZE;
    int history_counter = 0;
    int pos = 0;
    char c;

    while (1) {
        c = getchar();


        if (c == '\n') { // Enter key
            buf[pos] = '\0';
            printf("\n");
            return;
        } else if (c == 127 || c == '\b') { // Backspace
            if (pos > 0) {
                pos--;
                buf[pos] = '\0';
                printf("\b \b");
            }
        } else if (c == '\033') { // Inputting arrow keys
            getchar();           // Skipping the first '[' character
            char arrow = getchar();
            if (arrow == 'A' && history_counter < HISTORY_SIZE) { // Up arrow
                int prev_index = (index == 0) ? HISTORY_SIZE - 1 : (index - 1) % HISTORY_SIZE;
                if (command_log[prev_index] != NULL) {
                    index = (index == 0) ? HISTORY_SIZE - 1 : index - 1; // Decrease the index
                    history_counter++;

                    strcpy(buf, command_log[index]);
                    printf("\33[2K\r"); // Clear line
                    printf("[%s] $ %s", getcwd(NULL, 0), buf);
                    pos = strlen(buf);
                }
            } else if (arrow == 'B') { // Down arrow
                if (history_counter > 1) {
                    index = (index + 1) % HISTORY_SIZE;
                    history_counter--;

                    strcpy(buf, command_log[index]);
                    printf("\33[2K\r"); // Clear line
                    printf("[%s] $ %s", getcwd(NULL, 0), buf);
                    pos = strlen(buf);
                } else if (history_counter == 1) {
                    history_counter--;
                    index++;

                    buf[0] = '\0'; // Clear buffer
                    printf("\33[2K\r"); // Clear line
                    printf("[%s] $ ", getcwd(NULL, 0));
                    pos = 0;
                }
            }
        } else { // Regular character
            if (pos < MAX_SIZE - 1) {
                buf[pos++] = c;
                buf[pos] = '\0';
                printf("%c", c);
            }
        }
    }
}

int main() {
    char buf[MAX_SIZE];
    char* command_log[HISTORY_SIZE] = {NULL};
    int n = 0;

    tcgetattr(STDIN_FILENO, &orig_termios);

    // Register atexit to call DisableRawModeWrapper when the program exits
    atexit(DisableRawModeWrapper);

    while (1) {
        printf("[%s] $ ", getcwd(NULL, 0));

        // Enable raw mode for manual input handling
        EnableRawMode(&orig_termios);
        GetInputWithHistory(buf, command_log, n);
        DisableRawMode(&orig_termios);

        if (strcmp(buf, "exit") == 0) {
            break;
        }

        LogCommandHistory(buf, command_log, &n);
        printf("Executed: %s\n", buf); // For testing, replace with actual command handling
    }

    FreeCommandHistory(command_log, n);
    return 0;
}