#!./venv/bin/python3
import pandas as pd
import json
import matplotlib.pyplot as plt
import os
from datetime import timedelta

## Read the measurements data file ##
DATA_MEAS_DIR = 'data/measurements'
# Always plot latest datafile - replace [-1] with another index if you want to plot a specific file.
MEAS_LOG_FILE = sorted(os.listdir(DATA_MEAS_DIR))[-1]

# Store each dictionary of the measurements json in a list
with open(os.path.join(DATA_MEAS_DIR, MEAS_LOG_FILE)) as f:
    meas_data = [json.loads(line) for line in f]

# Use setpoint logger (only necessary for part two of the exercise "collecting fresh data")
use_setpoint_log = False


## Read the setpoints data file ##
if use_setpoint_log:
    DATA_SP_DIR = 'data/setpoints'
    # Always plot latest datafile
    SP_LOG_FILE = sorted(os.listdir(DATA_SP_DIR))[-1]

    # Store each dictionary of the setpoints json in a list
    with open(os.path.join(DATA_SP_DIR, SP_LOG_FILE)) as f:
        sp_data = [json.loads(line) for line in f]

    # Merge measurements and setpoints in one list
    data = meas_data + sp_data

else:
    data = meas_data


################################################################################
################## Question 3 ##################################################
################################################################################

# Construct a dataframe and pivot it to obtain a dataframe with a column per unit, and a row per timestamp.
df = pd.DataFrame.from_records(data)
df['time'] = pd.to_datetime(df['time'], unit='s')
df_pivot = df.pivot_table(values='value', columns='unit', index='time')
df_resampled = df_pivot.resample('s').mean()
df_resampled.interpolate(method='linear', inplace=True)
df_resampled = pd.DataFrame(df_resampled)
df_gaia = df_resampled['gaia_p']
df_gaia_diffs = df_gaia.diff()
gaia_min, gaia_max = df_gaia.min(), df_gaia.max()
diff_min, diff_max = df_gaia_diffs.min(), df_gaia_diffs.max()

print(f'{gaia_min=}, {gaia_max=}')
print(f'{diff_min=}, {diff_max=}')

# Plot the data. Note, that the data will mostly not be plotted with lines.
plt.ion()  # Turn interactive mode on
plt.figure()
ax1, ax2 = plt.subplot(211), plt.subplot(212)
df_gaia.plot(marker='.', ax=ax1, linewidth=3)
ax1.hlines([gaia_min, gaia_max], df_gaia.index.min(), df_gaia.index.max(), color='r')
df_gaia_diffs.plot(marker='.', ax=ax2, linewidth=3)
plt.show(block=True)

## gaia_min=0.62, gaia_max=7.085
## diff_min=-1.963, diff_max=1.3210000000000002