# coding=utf-8
# Copyright 2024 The Google Research Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Example script for generating plots like Figures 3 and 4 of the paper."""

import dataclasses
import os
import pathlib
from typing import List

from absl import app
from absl import flags
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
from tensorboard.backend.event_processing import event_accumulator

_PLOT_DIR = flags.DEFINE_string(
    "plot_dir",
    "/tmp/xirl/plots",
    "Directory wherein to store plots.")
_MATPLOTLIB_SIZE = flags.DEFINE_integer(
    "size",
    15,
    "Size multiplier for matplotlib figure.")
_STD_DEV_FRAC = flags.DEFINE_float(
    "std_dev_frac",
    0.5,
    "+/- standard deviation fraction.")
_MATPLOTLIB_DPI = flags.DEFINE_integer(
    "dpi",
    100,
    "Dots per inch for PNG plots.")


def update_plotting_params(size):
  plt.rcParams.update({
      "legend.fontsize": "large",
      "axes.titlesize": size,
      "axes.labelsize": size,
      "xtick.labelsize": size,
      "ytick.labelsize": size,
  })


def minimum_truncate_array_list(arrs):
  min_len = arrs[0].shape[0]
  for arr in arrs[1:]:
    if arr.shape[0] < min_len:
      min_len = arr.shape[0]
  return [arr[:min_len] for arr in arrs]


@dataclasses.dataclass
class Experiment:
  """Parses experiment data and computes statistics across seeds."""
  path: str
  name: str
  color: str
  linestyle: str

  def __post_init__(self):
    self.path = pathlib.Path(self.path)
    if not self.path.exists():
      raise ValueError(f"{self.path} does not exist.")
    # Find seed directories.
    subdirs = [f for f in self.path.iterdir() if f.is_dir()]
    # cd into their respective log subdirs.
    logdirs = [subdir / "tb" for subdir in subdirs]
    # Read Tensorboard logs.
    logfiles = [list(logdir.iterdir())[0] for logdir in logdirs]
    data = []
    for logfile in logfiles:
      ea = event_accumulator.EventAccumulator(str(logfile))
      ea.Reload()
      df = pd.DataFrame(ea.Scalars("evaluation/average_eval_scores"))
      arr = df[["step", "value"]].to_numpy()
      data.append(arr)
    self.data = minimum_truncate_array_list(data)

  @property
  def mean(self):
    return np.mean(self.data, axis=0)

  @property
  def std_dev(self):
    return np.std(self.data, axis=0)


def cross_shortstick(savename):
  """Aggregates returns across experiment seeds and generates a figure."""
  # Note: Append baselines or other methods to this list.
  experiments = [
      Experiment(
          # Note: replace with an actual experiment path.
          path="/PATH/TO/AN/EXPERIMENT/HERE/",
          # Note: You can customize the below attributes to your liking.
          name="XIRL",
          color="tab:red",
          linestyle="dashdot",
      ),
  ]

  _, ax = plt.subplots(1, constrained_layout=True)
  for experiment in experiments:
    return_mean = experiment.mean
    return_stddev = experiment.std_dev

    return_mean_x = return_mean[:, 0] / 1_000
    return_mean_y = return_mean[:, 1]

    ax.plot(
        return_mean_x,
        return_mean_y,
        lw=2,
        label=experiment.name,
        color=experiment.color,
        linestyle=experiment.linestyle,
    )
    ax.fill_between(
        return_mean_x,
        return_mean_y + _STD_DEV_FRAC.value * return_stddev[:, 1],
        return_mean_y - _STD_DEV_FRAC.value * return_stddev[:, 1],
        alpha=0.2,
        color=experiment.color,
    )

  ax.set_xlabel("Steps (thousands)")
  ax.set_ylabel("Success Rate")
  ax.set_title("short-stick")

  ax.legend(loc="lower right")
  ax.grid(linestyle="--", linewidth=0.5)

  plt.savefig(f"{_PLOT_DIR.value}/{savename}.pdf", format="pdf")
  plt.savefig(
      f"{_PLOT_DIR.value}/{savename}.png",
      format="png",
      dpi=_MATPLOTLIB_DPI.value,
  )
  plt.close()


def main(_):
  os.makedirs(_PLOT_DIR.value, exist_ok=True)
  update_plotting_params(_MATPLOTLIB_SIZE.value)
  cross_shortstick("cross_embodiment_shortstick")


if __name__ == "__main__":
  app.run(main)