# import sys module
import pygame
import sys


# pygame.init() will initialize all
# imported module
pygame.init()

clock = pygame.time.Clock()

# it will display on screen
screen = pygame.display.set_mode([600, 500])

# basic font for user typed
base_font = pygame.font.Font(None, 32)
user_text = ''

# create rectangle
input_rect = pygame.Rect(200, 200, 140, 32)

# color_active stores color(lightskyblue3) which
# gets active when input box is clicked by user
color_active = pygame.Color('lightskyblue3')

# color_passive store color(chartreuse4) which is
# color of input box.
color_passive = pygame.Color('chartreuse4')
color = color_passive

active = False

while True:
    for event in pygame.event.get():

      # if user types QUIT then the screen will close
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.MOUSEBUTTONDOWN:
            if input_rect.collidepoint(event.pos):
                active = True
            else:
                active = False

        if event.type == pygame.KEYDOWN:

            # Check for backspace
            if event.key == pygame.K_BACKSPACE:

                # get text input from 0 to -1 i.e. end.
                user_text = user_text[:-1]

            # Unicode standard is used for string
            # formation
            else:
                user_text += event.unicode
    
    # it will set background color of screen
    screen.fill((255, 255, 255))

    if active:
        color = color_active
    else:
        color = color_passive
        
    # draw rectangle and argument passed which should
    # be on screen
    pygame.draw.rect(screen, color, input_rect)

    text_surface = base_font.render(user_text, True, (255, 255, 255))
    
    # render at position stated in arguments
    screen.blit(text_surface, (input_rect.x+5, input_rect.y+5))
    
    # set width of textfield so that text cannot get
    # outside of user's text input
    input_rect.w = max(100, text_surface.get_width()+10)
    
    # display.flip() will update only a portion of the
    # screen to updated, not full area
    pygame.display.flip()
    
    # clock.tick(60) means that for every second at most
    # 60 frames should be passed.
    clock.tick(60)