# First, let us import the library we need.
import matplotlib.pyplot as plt

# Let us plot a simple line.
x = [1, 2, 3, 4, 5]
y = [1, 4, 9, 16, 25]

plt.plot(x, y)
plt.show()

# Let us add color and line style.
plt.plot(x, y, color='red', linestyle='--')
plt.show()

# Now we will add markers at each data point.
plt.plot(x, y, marker='o', color='blue', linestyle='-')
plt.show()

# Let us add a title and axis labels.
plt.plot(x, y, color='green', marker='s', linestyle='--')
plt.title('Simple Square Numbers Plot')
plt.xlabel('Input Value')
plt.ylabel('Square of Value')
plt.show()

# Let us add a legend to explain our data.
plt.plot(x, y, color='purple', marker='o', label='y is x squared')
plt.legend()
plt.title('Plot with Legend')
plt.xlabel('x')
plt.ylabel('y')
plt.show()

# Let us change the font size and style of labels.
plt.plot(x, y, color='orange', marker='^', label='x squared')
plt.title('Big Title', fontsize=20, fontname='Comic Sans MS')
plt.xlabel('Value', fontsize=14)
plt.ylabel('Squared Value', fontsize=14)
plt.legend(fontsize=12)
plt.show()

# Let us style the background and grid.
plt.style.use('ggplot')
plt.plot(x, y, color='blue', label='Nice Style')
plt.title('Styled with ggplot')
plt.grid(True)
plt.legend()
plt.show()

# Let us annotate the highest point.
plt.plot(x, y, marker='o')
plt.title('With Annotation')
plt.xlabel('x')
plt.ylabel('y')
plt.annotate('Biggest value', xy=(x[-1], y[-1]), xytext=(3, 20),
             arrowprops={'arrowstyle':'->', 'color':'red'}, color='red')
plt.show()

# Let us annotate multiple points with loops.
plt.plot(x, y, marker='*', color='brown')
for i, val in enumerate(x):
    plt.annotate(f'{val},{y[i]}', xy=(val, y[i]), xytext=(val+0.1, y[i]+0.5))
plt.title('Labeling All Points')
plt.show()

# Let us save our plot as an image file.
plt.plot(x, y, color='magenta')
plt.title('Save This Plot!')
plt.xlabel('Input')
plt.ylabel('Output')
plt.savefig('my_first_plot.png')
plt.show()

# Let us ask the user for a filename to save to.
filename = input('Enter a filename for your plot (for example: plot2.png): ')
plt.plot(x, y, color='teal')
plt.title('Custom Filename Example')
plt.savefig(filename)
plt.show()

# Let us save a plot without showing it, useful for scripts.
plt.plot(x, y, color='navy')
plt.title('Saved, Not Shown')
plt.savefig('no_show_plot.png')
plt.close()

# Sample data for temperatures over a week.
days = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
temps = [22, 21, 23, 25, 24, 20, 19]

plt.figure(figsize=(8,5))
plt.plot(days, temps, marker='o', color='tomato', linestyle='-', label='Temperature (C)')
plt.title('Daily High Temperatures', fontsize=16)
plt.xlabel('Day of Week')
plt.ylabel('Temperature (C)')
plt.grid(True)
plt.legend()
plt.annotate('Warmest', xy=('Thu',25), xytext=('Wed',26.5),
             arrowprops={'arrowstyle':'->', 'color':'red'}, color='red')
plt.savefig('weekly_temps.png')
plt.show()

# Challenge: Label days colder than 21 degrees with a note.
plt.plot(days, temps, marker='o', color='navy', label='Temp')
for i, val in enumerate(temps):
    if val < 21:
        plt.annotate('Cold', xy=(days[i], val), xytext=(days[i], val-1))
plt.title('Colder Days Labeled')
plt.xlabel('Day')
plt.ylabel('Temp (C)')
plt.grid(True)
plt.legend()
plt.show()

# Let us check our knowledge: Can you add an annotation, customize style, and save?
# Try using a different dataset or styling option!