# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

# This file is adpated from PyTorch Core
# https://github.com/pytorch/pytorch/blob/master/scripts/release_notes/common.py

import json
import locale
import os
import re
import subprocess
from collections import namedtuple

import requests


topics = [
    "bc_breaking",
    "deprecations",
    "new_features",
    "improvements",
    "bug_fixes",
    "performance",
    "docs",
    "devs",
    "Untopiced",
]


Features = namedtuple(
    "Features",
    [
        "title",
        "body",
        "pr_number",
        "files_changed",
        "labels",
    ],
)


def dict_to_features(dct):
    return Features(
        title=dct["title"],
        body=dct["body"],
        pr_number=dct["pr_number"],
        files_changed=dct["files_changed"],
        labels=dct["labels"],
    )


def features_to_dict(features):
    return dict(features._asdict())


def run(command):
    """Returns (return-code, stdout, stderr)"""
    p = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
    output, err = p.communicate()
    rc = p.returncode
    enc = locale.getpreferredencoding()
    output = output.decode(enc)
    err = err.decode(enc)
    return rc, output.strip(), err.strip()


def commit_body(commit_hash):
    cmd = f"git log -n 1 --pretty=format:%b {commit_hash}"
    ret, out, err = run(cmd)
    return out if ret == 0 else None


def commit_title(commit_hash):
    cmd = f"git log -n 1 --pretty=format:%s {commit_hash}"
    ret, out, err = run(cmd)
    return out if ret == 0 else None


def commit_files_changed(commit_hash):
    cmd = f"git diff-tree --no-commit-id --name-only -r {commit_hash}"
    ret, out, err = run(cmd)
    return out.split("\n") if ret == 0 else None


def parse_pr_number(body, commit_hash, title):
    regex = r"Pull Request resolved: https://github.com/pytorch/data/pull/([0-9]+)"
    matches = re.findall(regex, body)
    if len(matches) == 0:
        if "revert" not in title.lower() and "updating submodules" not in title.lower():
            print(f"[{commit_hash}: {title}] Could not parse PR number, ignoring PR")
        return None
    if len(matches) > 1:
        print(f"[{commit_hash}: {title}] Got two PR numbers, using the first one")
        return matches[0]
    return matches[0]


def get_ghstack_token():
    pattern = "github_oauth = (.*)"
    with open(os.path.expanduser("~/.ghstackrc"), "r+") as f:
        config = f.read()
    matches = re.findall(pattern, config)
    if len(matches) == 0:
        raise RuntimeError("Can't find a github oauth token")
    return matches[0]


token = get_ghstack_token()
headers = {"Authorization": f"token {token}"}


def run_query(query):
    request = requests.post("https://api.github.com/graphql", json={"query": query}, headers=headers)
    if request.status_code == 200:
        return request.json()
    else:
        raise Exception(f"Query failed to run by returning code of {request.status_code}. {query}")


def gh_labels(pr_number):
    query = f"""
    {{
      repository(owner: "pytorch", name: "data") {{
        pullRequest(number: {pr_number}) {{
          labels(first: 10) {{
            edges {{
              node {{
                name
              }}
            }}
          }}
        }}
      }}
    }}
    """
    query = run_query(query)
    edges = query["data"]["repository"]["pullRequest"]["labels"]["edges"]
    return [edge["node"]["name"] for edge in edges]


def get_features(commit_hash, return_dict=False):
    title, body, files_changed = (
        commit_title(commit_hash),
        commit_body(commit_hash),
        commit_files_changed(commit_hash),
    )
    pr_number = parse_pr_number(body, commit_hash, title)
    labels = []
    if pr_number is not None:
        labels = gh_labels(pr_number)
    result = Features(title, body, pr_number, files_changed, labels)
    if return_dict:
        return features_to_dict(result)
    return result


class CommitDataCache:
    def __init__(self, path="results/data.json"):
        self.path = path
        self.data = {}
        if os.path.exists(path):
            self.data = self.read_from_disk()

    def get(self, commit):
        if commit not in self.data.keys():
            # Fetch and cache the data
            self.data[commit] = get_features(commit)
            self.write_to_disk()
        return self.data[commit]

    def read_from_disk(self):
        with open(self.path) as f:
            data = json.load(f)
            data = {commit: dict_to_features(dct) for commit, dct in data.items()}
        return data

    def write_to_disk(self):
        data = {commit: features._asdict() for commit, features in self.data.items()}
        with open(self.path, "w") as f:
            json.dump(data, f)