#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>

#ifndef CTURTLE_H
#define CTURTLE_H

//////////////////////////////////////////////////////////////////////////////
////////////////////////// BASIC STRUCTURES AND TYPEDEFS /////////////////////
//////////////////////////////////////////////////////////////////////////////

#pragma pack(push, 1) // force compiler to not use padding in laying out this struct in memory
/**
 * Represents a color with red, green, and blue components.
 */
struct Color {
    uint8_t r;
    uint8_t g;
    uint8_t b;
};
typedef struct Color Color; // The Color type by itself refers to the struct as a whole.
#pragma pack(pop) // undo the previous pack directive

/**
 * Represents an image in memory, in addition to the current state of the turtle associated with it.
 */
struct Image {
    struct Color* pixels; // an heap-allocated array of Color structs, each representing
                          // 3 channels of color -- number of elements is width*height
    int width;  // width of the image, in pixels
    int height; // height of the image, in pixels
    
    // turtle settings:
    int turtle_x; // current x coordinate
    int turtle_y; // current y coordiante
    int turtle_angle; // current angle, in degrees
    bool turtle_pen_down; // true if the drawing pen is "down" (enabled)
    Color turtle_color; // current color of the turtle
    
};
typedef struct Image* Image; // The Image type by itself refers to a _pointer_ to a struct Image!

//////////////////////////////////////////////////////////////////////////////
////////////////////////// IMAGE CREATE/READ ROUTINES ////////////////////////
//////////////////////////////////////////////////////////////////////////////

/**
 * Create a new image of the given dimensions, all pixels defaulting to black.
 * The default settings for the turtle are:
 *   Position: center of image
 *   Direction: north
 *   Pen: down
 *   Color: white
 */
Image create_image(int width, int height);

/**
 * Reads the given file and returns a new Image struct representing it.
 * If there is an error, return NULL, and the error encountered is available via get_last_error().
 * The default settings for the turtle are:
 *   Position: center of image
 *   Direction: north
 *   Pen: down
 *   Color: white
 */
Image read_tga(const char* filename);

/**
 * Reads the given file and returns a new Image struct representing it.
 * Automatically distinguishes between ASCII ("P3") and binary ("P6") formats.
 * If there is an error, return NULL, and the error encountered is available via get_last_error().
 * The default settings for the turtle are:
 *   Position: center of image
 *   Direction: north
 *   Pen: down
 *   Color: white
 */
Image read_ppm(const char* filename);

//////////////////////////////////////////////////////////////////////////////
////////////////////////// IMAGE DESTRUCTOR //////////////////////////////////
//////////////////////////////////////////////////////////////////////////////

/**
 * Free memory associated with the given image.
 */
void destroy_image(Image image);

//////////////////////////////////////////////////////////////////////////////
////////////////////////// IMAGE WRITING ROUTINES ////////////////////////////
//////////////////////////////////////////////////////////////////////////////

/**
 * Write the image to a Targa (TGA) file.  See the assignment description for file
 * format limitations.
 */
bool write_tga(const char* filename, Image image);

/**
 * Write the image to a Portable Pixel Map (PPM) file.  See the assignment
 * description for file format limitations.
 * If ascii is true, then the human-readable "P3" ASCII file format will be used.
 * If ascii is false, then the binary "P6" file format will be used.
 */
bool write_ppm(const char* filename, Image image, bool ascii);

//////////////////////////////////////////////////////////////////////////////
////////////////////////// DIRECT GRAPHICS ROUTINES //////////////////////////
//////////////////////////////////////////////////////////////////////////////

/**
 * Set the given pixel to the given color.
 */
void do_pixel(Image image, int x, int y, Color color);

/**
 * Draw a line from (x0,y0) to (x1,y1) using the given color.
 */
void do_line(Image image, int x0, int y0, int x1, int y1, Color color);

/**
 * Blank the entire canvas with the given color.
 */
void do_clear(Image image, Color color);

/**
 * Invert all pixels of the image, giving the "negative" image.
 * This is equivalent to doing "v = 255 - v" or "v = ~v" on all the color components.
 */
void do_invert(Image image);

/**
 * Switch red and blue channels in the image.
 * This is needed internally to write out a TGA file, but it's also a neat looking
 * effect in general when applied to photographs.
 */
void do_reverse_rgb(Image image);

//////////////////////////////////////////////////////////////////////////////
////////////////////////// TURTLE GRAPHICS ROUTINES //////////////////////////
//////////////////////////////////////////////////////////////////////////////

/**
 * Move the turtle to the given position without drawing anything.
 * Returns false if the destination it outside the image bounds.
 */
bool turtle_set_xy(Image image, int x, int y);

/**
 * Move the turtle to the given position, drawing a line as it goes if the pen is down
 * Returns false if the destination it outside the image bounds.
 */
bool turtle_move(Image image, int x, int y);

/**
 * Move the turtle int he current direction by d pixels, drawing as it goes if the pen is down
 * Returns false if the destination it outside the image bounds.
 */
bool turtle_forward(Image image, int d);

/**
 * Reset the angle of the turtle to north
 */
void turtle_face_north(Image image);

/**
 * Turn left by the number of degrees given.
 */
void turtle_left(Image image, int delta);

/**
 * Turn right by the number of degrees given.
 */
void turtle_right(Image image, int delta);

/**
 * Lift the "pen", causing turtle move and forward to not draw anything.
 */
void turtle_pen_up(Image image);

/**
 * Put the "pen" down, causing turtle move and forward to draw lines.
 */
void turtle_pen_down(Image image);

/**
 * Change the current turtle color.
 */
void turtle_set_color(Image image, Color color);

//////////////////////////////////////////////////////////////////////////////
////////////////////////// ERROR HANDLING ROUTINES ///////////////////////////
//////////////////////////////////////////////////////////////////////////////

/**
 * Return a string representing the last error encountered by the library.
 */
const char* get_last_error();

//////////////////////////////////////////////////////////////////////////////
////////////////////////// OPTIONAL EXTENDED FUNCTIONS ///////////////////////
//////////////////////////////////////////////////////////////////////////////

// (you may add extra functions here to add new capabilities to your library)

#endif