/*******************************************************************************************
*
*   raylib [shapes] example - lines drawing
*
*   Example complexity rating: [★☆☆☆] 1/4
*
*   Example originally created with raylib 5.6-dev, last time updated with raylib 5.6
*
*   Example contributed by Robin (@RobinsAviary) and reviewed by Ramon Santamaria (@raysan5)
*
*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
*   BSD-like license that allows static linking with closed source software
*
*   Copyright (c) 2025-2025 Robin (@RobinsAviary)
*
********************************************************************************************/

#include "raylib.h"
#include "raymath.h"

//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
	// Initialization
	//--------------------------------------------------------------------------------------
	const int screenWidth = 800;
	const int screenHeight = 450;

	InitWindow(screenWidth, screenHeight, "raylib [shapes] example - lines drawing");

	// Hint text that shows before you click the screen
	bool startText = true;

	// The mouse's position on the previous frame
	Vector2 mousePositionPrevious = GetMousePosition();

	// The canvas to draw lines on
	RenderTexture canvas = LoadRenderTexture(screenWidth, screenHeight);

	// The background color of the canvas
	const Color backgroundColor = RAYWHITE;

	// The line's thickness
	float lineThickness = 8.0f;
	// The lines hue (in HSV, from 0-360)
	float lineHue = 0.0f;

	// Clear the canvas to the background color
	BeginTextureMode(canvas);
		ClearBackground(backgroundColor);
	EndTextureMode();
	//--------------------------------------------------------------------------------------

	// Main game loop
	while (!WindowShouldClose())    // Detect window close button or ESC key
	{
		// Update
		//----------------------------------------------------------------------------------
		// Disable the hint text once the user clicks
		if (IsMouseButtonPressed(MOUSE_BUTTON_LEFT) && startText)
		{
			startText = false;
		}

		// Clear the canvas when the user middle-clicks
		if (IsMouseButtonPressed(MOUSE_BUTTON_MIDDLE))
		{
			BeginTextureMode(canvas);
				ClearBackground(backgroundColor);
			EndTextureMode();
		}

		// Store whether the left and right buttons are down
		bool leftButtonDown = IsMouseButtonDown(MOUSE_BUTTON_LEFT);
		bool rightButtonDown = IsMouseButtonDown(MOUSE_BUTTON_RIGHT);

		if (leftButtonDown || rightButtonDown)
		{
			// The color for the line
			Color drawColor;

			if (leftButtonDown)
			{
				// Increase the hue value by the distance our cursor has moved since the last frame (divided by 3)
				lineHue += Vector2Distance(mousePositionPrevious, GetMousePosition())/3.0f;

				// While the hue is >=360, subtract it to bring it down into the range 0-360
				// This is more visually accurate than resetting to zero
				while (lineHue >= 360.0f)
				{
					lineHue -= 360.0f;
				}

				// Create the final color
				drawColor = ColorFromHSV(lineHue, 1.0f, 1.0f);
			}
			else if (rightButtonDown) 
			{
				// Use the background color as an "eraser"
				drawColor = backgroundColor;
			}

			// Draw the line onto the canvas
			BeginTextureMode(canvas);
				// Circles act as "caps", smoothing corners
				DrawCircleV(mousePositionPrevious, lineThickness/2.0f, drawColor);
				DrawCircleV(GetMousePosition(), lineThickness/2.0f, drawColor);
				DrawLineEx(mousePositionPrevious, GetMousePosition(), lineThickness, drawColor);
			EndTextureMode();
		}

		// Update line thickness based on mousewheel
		lineThickness += GetMouseWheelMove();
		lineThickness = Clamp(lineThickness, 1.0, 500.0f);

		// Update mouse's previous position
		mousePositionPrevious = GetMousePosition();
		//----------------------------------------------------------------------------------

		// Draw
		//----------------------------------------------------------------------------------
		BeginDrawing();
			// Draw the render texture to the screen, flipped vertically to make it appear top-side up
			DrawTextureRec(canvas.texture, (Rectangle){ 0.0f, 0.0f, (float)canvas.texture.width,(float)-canvas.texture.height }, Vector2Zero(), WHITE);

			// Draw the preview circle
			if (!leftButtonDown) DrawCircleLinesV(GetMousePosition(), lineThickness/2.0f, (Color){ 127, 127, 127, 127 });

			// Draw the hint text
			if (startText) DrawText("try clicking and dragging!", 275, 215, 20, LIGHTGRAY);
		EndDrawing();
		//----------------------------------------------------------------------------------
	}

	// De-Initialization
	//--------------------------------------------------------------------------------------
	// Unload the canvas render texture
	UnloadRenderTexture(canvas);

	CloseWindow();        // Close window and OpenGL context
	//--------------------------------------------------------------------------------------

	return 0;
}