from collections import defaultdict
import argparse, os, subprocess, docker
from typing import Any, Callable
from github.PullRequest import PullRequest
from github.Repository import Repository
import pandas as pd
from github import Github, GithubException
from tqdm import tqdm
from datetime import datetime

from dataset import Dataset, DatasetEntry, FileData, Metadata
from handlers import HandlerException, get_build_handler
from utils import has_only_1_comment, move_github_logging_to_file, clone


def get_good_projects(csv_file: str) -> pd.DataFrame:
    """
    Extracts the good (the ones that compile and test successfully, and that
    have at least one test) from the given file.

    Parameters:
    csv_file (str): The csv file containing the projects.

    Returns:
    pd.DataFrame: The good projects.
    """
    df = pd.read_csv(csv_file)
    return df.loc[(df['good_repo_for_crab'] == True) & (df['n_tests'] > 0)]


def is_pull_good(pull: PullRequest, verbose: bool = False):
    return (
        has_only_1_comment(pull.get_commits(), pull.get_review_comments(), verbose=verbose)
        and pull.user.type != "Bot"
    )


def run_git_cmd(cmd: list[str], repo_path: str) -> subprocess.CompletedProcess:
    return subprocess.run(
        ["git", "-C", repo_path] + cmd,
        check=True,
        capture_output=True,
        text=True,
    )


def ensure_full_history(repo_path: str) -> None:
    result = run_git_cmd(["rev-parse", "--is-shallow-repository"], repo_path)

    if result.stdout.strip() == "true":
        run_git_cmd(["fetch", "--unshallow"], repo_path)


def reset_repo_to_latest_commit(repo_path: str) -> None:
    current_branch = run_git_cmd(["rev-parse", "--abbrev-ref", "HEAD"], repo_path).stdout.strip()
    run_git_cmd(["reset", "--hard", current_branch], repo_path)


def process_pull(
    repo: Repository,
    pr: PullRequest,
    dataset: Dataset,
    repos_dir: str,
    cache: dict[str, dict[int, DatasetEntry]] = {},
):
    if pr.number in cache.get(repo.full_name, set()):
        dataset.entries.append(cache[repo.full_name][pr.number])
        return

    commits = list(pr.get_commits())
    if not commits:
        return  # No commits, skip processing

    first_commit = commits[0]
    last_commit = commits[-1]

    try:
        diffs_before = {
            file.filename: file.patch for file in repo.compare(pr.base.sha, first_commit.sha).files
        }
    except GithubException as e:
        return

    comments = list(pr.get_review_comments())
    assert len(comments) == 1
    comment = comments[0]
    comment_text = comment.body
    commented_file_path = comment.path

    try:
        diffs_after = {
            file.filename: file.patch
            for file in repo.compare(first_commit.sha, last_commit.sha).files
        }
    except GithubException as e:
        return

    entry = DatasetEntry(
        metadata=Metadata(
            repo.full_name,
            pr.number,
            pr.merge_commit_sha,
            {comment_text: commented_file_path},
            reason_for_failure="Was still being processed",
        ),
        files={file.filename: FileData(file.filename) for file in pr.get_files()},
        diffs_before=diffs_before,
        comments=[comment_text],
        diffs_after=diffs_after,
    )
    dataset.entries.append(entry)

    repo_path = os.path.join(repos_dir, repo.full_name)

    updates = {}
    if not clone(repo.full_name, repos_dir, updates):
        entry.metadata.last_cmd_error_msg = updates["error_msg"]
        entry.metadata.reason_for_failure = "Couldn't clone the repo successfully"
        entry.metadata.successful = False

    def _try_cmd(action: Callable[[], Any], reason_for_failure: str) -> bool:
        """
        Tries a command, and if it fails, it sets the metadata of the entry.
        """
        try:
            # return action()
            action()
        except subprocess.CalledProcessError as e:
            entry.metadata.last_cmd_error_msg = f"{e.stderr}"
            entry.metadata.reason_for_failure = reason_for_failure
            entry.metadata.successful = False
            # raise e
        return entry.metadata.successful

    if not _try_cmd(
        lambda: ensure_full_history(repo_path),
        "Couldn't ensure the full history of the repo (fetch --unshallow)",
    ):
        return

    try:
        run_git_cmd(["checkout", pr.merge_commit_sha], repo_path)
    except subprocess.CalledProcessError:
        if not _try_cmd(
            lambda: run_git_cmd(["fetch", "origin", f"pull/{pr.number}/merge"], repo_path),
            "Couldn't fetch the PR's merge commit",
        ):
            return

        if not _try_cmd(
            lambda: run_git_cmd(["checkout", pr.merge_commit_sha], repo_path),
            "Coudln't checkout the PR's merge commit (even after fetching the pull/<pr_number>/merge)",
        ):
            return

    build_handler = get_build_handler(repos_dir, repo.full_name, updates)
    if build_handler is None:
        entry.metadata.last_cmd_error_msg = updates["error_msg"]
        entry.metadata.reason_for_failure = "Couldn't get the build handler"
        entry.metadata.successful = False
        return
    entry.metadata.build_system = build_handler.get_type()
    build_handler.set_client(docker_client)

    def _check_coverages():
        for coverage_file, coverage in build_handler.check_coverage(commented_file_path):
            entry.metadata.commented_files_coverages[commented_file_path][coverage_file] = coverage

    steps = [
        ("Checking for tests...", build_handler.check_for_tests),
        ("Compiling...", build_handler.compile_repo),
        ("Running tests...", build_handler.test_repo),
        ("Generating coverage...", build_handler.generate_coverage_report),
        ("Checking coverage...", _check_coverages),
    ]

    with build_handler, tqdm(total=len(steps), desc="Processing PR", leave=False) as pbar:
        try:
            for message, action in steps:
                pbar.set_postfix(
                    {
                        "doing": message,
                        "started at": datetime.now().strftime("%d/%m, %H:%M:%S"),
                    }
                )
                action()
                pbar.update(1)
        except HandlerException as e:
            entry.metadata.last_cmd_error_msg = str(e)
            entry.metadata.reason_for_failure = e.reason_for_failure
            entry.metadata.successful = False
        finally:
            build_handler.clean_repo()
            reset_repo_to_latest_commit(repo_path)

    if entry.metadata.successful:
        entry.metadata.reason_for_failure = ""  # was set to 'still processing', since it's done being processed and was successful, there are no reasons for failure


def process_repo(
    repo_name: str,
    dataset: Dataset,
    repos_dir: str,
    cache: dict[str, dict[int, DatasetEntry]] = {},
):
    repo = g.get_repo(repo_name)
    if repo.full_name in cache:
        dataset.entries.extend(cache[repo.full_name].values())
        dataset.to_json(args.output)

    prs = repo.get_pulls(state="closed")

    n_good_prs = 0
    with tqdm(prs, desc="Processing prs", leave=False) as pbar:
        for pr in pbar:
            pbar.set_postfix({"pr": pr.number, "# new good found": n_good_prs})
            if pr.merged_at is None:
                pbar.update(1)
                continue
            if is_pull_good(pr):
                n_good_prs += 1
                process_pull(repo, pr, dataset, repos_dir, cache)
                dataset.to_json(args.output)


def process_repos(
    df: pd.DataFrame,
    dataset: Dataset,
    repos_dir: str,
    cache: dict[str, dict[int, DatasetEntry]] = {},
):
    """
    Processes the repos in the given csv file, extracting the good ones and
    creating the "triplets" for the dataset.

    Parameters:
    csv_file (str): The csv file containing the projects.
    dataset (Dataset): The dataset in which the triplets will be stored.
        Passing it by reference in order have the latest information, in case of an error
    verbose (bool): Whether to be verbose or not
    """
    with tqdm(total=len(df), desc="Processing repos") as pbar:
        for _, row in df.iterrows():
            repo_name = row["name"]
            assert isinstance(repo_name, str)
            pbar.set_postfix(
                {
                    "repo": repo_name,
                    "started at": datetime.now().strftime("%d/%m, %H:%M:%S"),
                    "# triplets": f"{len(dataset)}/{len(dataset.entries)} ({len(dataset)/len(dataset.entries) if len(dataset.entries) > 0 else 0:.2%})",
                }
            )
            process_repo(repo_name, dataset, repos_dir, cache)
            pbar.update(1)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Creates the triplets for the CRAB dataset.')
    parser.add_argument(
        'csv_file',
        type=str,
        help='The csv file containing the projects (the results from clone_repos.py).',
    )
    parser.add_argument(
        '-o',
        '--output',
        type=str,
        default="./dataset.json",
        help='The file in which the dataset will be contained. Default is "./dataset.json"',
    )
    parser.add_argument(
        '-r',
        '--repos',
        type=str,
        default="./results/",
        help='The directory in which the repos were cloned (will be cloned if they aren\'t there already). Default: "./results/"',
    )
    parser.add_argument(
        '-c',
        '--cache',
        type=str,
        help="The name of the output file from another run of this script. This is for when the script unexpectedly got interrupted and you want to resume from where you left off.",
    )
    # parser.add_argument('-v', '--verbose', action='store_true', help='Prints the number of good projects.')
    parser.add_argument(
        "--only-repo",
        type=str,
        help="If this argument is not provided, all the repos in the '--repos' csv will be processed. If instead you want to run the script on a single repo (for testing purposes mainly) provide a string of form 'XXX/YYY' to this argument, where XXX is the owner of the repo and YYY is the name of the repo",
    )

    args = parser.parse_args()
    g = Github(os.environ["GITHUB_AUTH_TOKEN_CRAB"])
    docker_client = docker.from_env()
    move_github_logging_to_file()

    df = get_good_projects(args.csv_file)

    if args.only_repo is not None:
        df = df.loc[df["name"] == args.only_repo]

    cache: dict[str, dict[int, DatasetEntry]] = defaultdict(dict)
    if args.cache is not None:
        cache_dataset = Dataset.from_json(args.cache)
        for cache_entry in cache_dataset.entries:
            cache[cache_entry.metadata.repo][cache_entry.metadata.pr_number] = cache_entry

    dataset = Dataset()
    try:
        # try and finally to save, regardless of an error occuring or the program finished correctly
        process_repos(df, dataset, args.repos, cache)
    finally:
        dataset.to_json(args.output)