import os
import sys
import re
import json
import requests

# Read inputs from environment variables
platform = os.environ.get("PLATFORM", "github").lower()
token = os.environ["TOKEN"]
owner = os.environ.get("REPO_OWNER", os.environ.get("GITHUB_REPOSITORY_OWNER"))
repo = os.environ.get("REPO_NAME", os.environ.get("GITHUB_REPOSITORY"))
pr_index = os.environ["PR_INDEX"]
api_url = os.environ.get("API_URL", os.environ.get("GITHUB_API_URL"))
diff_text = os.environ.get("DIFF")  # optional
comment_template = os.environ.get("COMMENT_TEMPLATE", "Auto-comment: changed line -> {line}")

if not token or not pr_index:
    print("TOKEN and PR_INDEX are required.", file=sys.stderr)
    sys.exit(1)

# If diff_text is empty, just post a general PR comment
if not diff_text:
    body = comment_template.replace("{line}", "").replace("{lines}", "")
    if platform == "github":
        url = f"https://api.github.com/repos/{owner}/{repo}/issues/{pr_index}/comments"
        payload = {"body": body}
    elif platform == "gitea":
        if not api_url:
            print("Gitea API URL required for Gitea platform", file=sys.stderr)
            sys.exit(1)
        url = f"{api_url}/repos/{owner}/{repo}/pulls/{pr_index}/comments"
        payload = {"body": body}
    else:
        print(f"Unsupported platform: {platform}", file=sys.stderr)
        sys.exit(1)

    headers = {"Authorization": f"token {token}", "Content-Type": "application/json"}
    resp = requests.post(url, headers=headers, json=payload)
    if resp.status_code in (200, 201):
        print("General comment posted successfully!")
        sys.exit(0)
    else:
        print(f"Failed to post comment: {resp.status_code}", file=sys.stderr)
        print(resp.text, file=sys.stderr)
        sys.exit(1)

# --- If diff_text exists, parse diff normally ---
diff_files = {}
current_file = None
new_line_num = None

for line in diff_text.splitlines():
    if line.startswith("+++ b/"):
        current_file = line[6:].strip()
        diff_files[current_file] = []
        new_line_num = 0
    elif line.startswith("@@"):
        m = re.match(r"@@ -\d+(?:,\d+)? \+(\d+)(?:,(\d+))? @@", line)
        if m:
            new_line_num = int(m.group(1)) - 1
    elif line.startswith("+") and not line.startswith("+++"):
        new_line_num += 1
        content = line[1:]
        diff_files[current_file].append((new_line_num, content))
    elif not line.startswith("-"):
        new_line_num += 1

# Post comments for each added line
for file_path, lines in diff_files.items():
    if not lines:
        continue
    all_lines_content = "\n".join([line_content for _, line_content in lines])
    for line_number, line_content in lines:
        body = comment_template.replace("{line}", line_content).replace("{lines}", all_lines_content)

        if platform == "github":
            url = f"https://api.github.com/repos/{owner}/{repo}/pulls/{pr_index}/comments"
            payload = {"body": body, "path": file_path, "position": line_number}
        elif platform == "gitea":
            if not api_url:
                print("Gitea API URL required", file=sys.stderr)
                sys.exit(1)
            url = f"{api_url}/repos/{owner}/{repo}/pulls/{pr_index}/comments"
            payload = {"body": body, "path": file_path, "position": line_number}
        else:
            print(f"Unsupported platform: {platform}", file=sys.stderr)
            sys.exit(1)

        headers = {"Authorization": f"token {token}", "Content-Type": "application/json"}
        resp = requests.post(url, headers=headers, json=payload)
        if resp.status_code in (200, 201):
            print(f"Comment posted on {file_path}:{line_number}")
        else:
            print(f"Failed to post comment on {file_path}:{line_number} ({resp.status_code})", file=sys.stderr)
            print(resp.text, file=sys.stderr)