import os, requests, re
from datetime import datetime
from typing import Optional

COMMON_HEADERS = {
    'Accept': 'application/vnd.github+json',
    'Authorization': f'Bearer {os.environ["GITHUB_AUTH_TOKEN_CRAB"]}',
    'X-Github-Api-Version': '2022-11-28',
}

def github_call(url):
    return requests.get(url, headers=COMMON_HEADERS)

def get_comments(repo_url: str, pr_number: str) -> list[dict]:
    response = github_call(f'{repo_url}/pulls/{pr_number}/comments')
    return response.json()

def get_commits(repo_url: str, pr_number: str) -> list[dict]:
    response = github_call(f'{repo_url}/pulls/{pr_number}/commits')
    return response.json()

def parse_date(date: str) -> datetime:
    return datetime.strptime(date, "%Y-%m-%dT%H:%M:%SZ")

def get_first_comment_date(comments: list[dict]) -> datetime:
    return min([parse_date(comment['created_at']) for comment in comments])

def get_useful_commits(commits: list[dict], first_comment_date: datetime) -> list[dict]:
    ret = []
    for commit in commits:
        if ("commit" not in commit 
                and "author" not in commit["author"] 
                and "date" not in commit['commit']['author']):
            continue
        commit_date = parse_date(commit['commit']['author']['date'])
        if commit_date > first_comment_date:
            ret.append(commit)
    return ret

def parse_hunk_header(hunk_header) -> Optional[dict]:
    """Extracts line ranges from a diff hunk header."""
    match = re.match(r'@@ -(\d+),?(\d*) \+(\d+),?(\d*) @@', hunk_header)
    if match:
        old_start = int(match.group(1))
        old_count = int(match.group(2)) if match.group(2) else 1
        new_start = int(match.group(3))
        new_count = int(match.group(4)) if match.group(4) else 1
        return {
            "old_range": {
                "start" : old_start,
                "end" : old_start + old_count - 1
            },
            "new_range": {
                "start" : new_start,
                "end" : new_start + new_count - 1
            },
        }
    return None

def augment_comments(comments: list[dict]) -> list[dict]:
    ret = []
    for comment in comments:
        new_comment = comment.copy()
        if "diff_hunk" not in comment:
            continue
        new_comment["hunk_range"] = parse_hunk_header(comment["diff_hunk"])
        ret.append(new_comment)
    return ret


def process_pull_request(repo_url: str, pr_number: str) -> bool:
    comments = augment_comments(get_comments(repo_url, pr_number))

    if len(comments) == 0:
        # No comments, can't extract triplet
        return False


    first_comment_date = get_first_comment_date(comments)
    commits = get_commits(repo_url, pr_number)

    if len(commits) == 0:
        # No commits, can't extract triplet
        return False

    # filter out the commits that are older than the first comment, since they are the commits relevant for the PR
    actual_commits = get_useful_commits(commits, first_comment_date)

    if len(actual_commits) == 0:
        # No commits after the first comment, there were no revision from the contributor, so no triplet
        return False


    for commit in actual_commits:
        print(f"Commit: {commit['sha']}")
        print(f"Author: {commit['author']['login']}")
        print(f"Date: {commit['commit']['author']['date']}")
        print(f"Message: {commit['commit']['message']}")
        print("")

    return True




if __name__ == "__main__":
    response  = github_call('https://api.github.com/repos/cdk/cdk/pulls/1140/commits')
    response  = github_call('https://api.github.com/repos/cdk/cdk/pulls/1140/commits')
    process_pull_request('https://api.github.com/repos/cdk/cdk', '1140')