import matplotlib.pyplot as plt

from metro1_data import tas, costs

# Update matplotlib parameters.
params = {'text.usetex': True,
          'figure.dpi': 200,
          'font.size': 14,
          'font.serif': [],
          'font.sans-serif': [],
          'font.monospace': [],
          'axes.labelsize': 16,
          'axes.titlesize': 18,
          'axes.linewidth': .6,
          'legend.fontsize': 14,
          'xtick.labelsize': 12,
          'ytick.labelsize': 12,
          'font.family': 'serif'}
plt.rcParams.update(params)

plt.figure(figsize=(7, 5))

plt.plot(tas, costs, 'o-')

idx = 3
plt.plot([tas[idx], tas[idx+1], tas[idx+1]],
         [costs[idx], costs[idx], costs[idx+1]],
         linestyle='dashed', color='black')
plt.annotate('$b_i$', ((tas[idx]+tas[idx+1])/2, (costs[idx]+costs[idx+1])/2),
             va='top', ha='left')

plt.xlabel('$ta$')
plt.ylabel('$c$')
plt.xlim(tas[0], tas[-1])
# plt.ylim(bottom=0)
plt.tight_layout()
plt.show()