#!/usr/bin/env python3
import subprocess
import os
import re
import argparse

# --- Configuration ---
INPUT_FILE = "issues-to-create.md"
DEFAULT_PROJECT_TITLE = None
DEFAULT_MILESTONE = "Milestone 4"
# ---

def parse_issues(content):
    """Parse issue blocks from markdown content.
    
    Each issue block starts with a '# Title' line, followed by an optional
    'Labels:' metadata line, then the body. Milestone is set globally, not per-issue.
    """
    issue_blocks = re.split(r'\n(?=#\s)', content)
    issues = []

    for block in issue_blocks:
        if not block.strip():
            continue

        lines = block.strip().split('\n')

        # Title: strip leading '#' characters and whitespace
        title = re.sub(r'^#+\s*', '', lines[0]).strip()

        labels_line = ""
        body_start_index = len(lines)  # default: no body

        # Only 'Labels:' is parsed from the markdown; milestone is global
        for i, line in enumerate(lines[1:], start=1):
            stripped = line.strip()
            if stripped.lower().startswith('labels:'):
                labels_line = stripped.split(':', 1)[1].strip()
            elif stripped == "":
                continue  # skip blank separator lines in the header
            else:
                body_start_index = i
                break

        body = "\n".join(lines[body_start_index:]).strip()
        labels = [label.strip() for label in labels_line.split(',') if label.strip()]

        if not title:
            print("⚠️  Skipping block with no title.")
            continue

        issues.append({
            "title": title,
            "body": body,
            "labels": labels,
        })

    return issues


def main():
    parser = argparse.ArgumentParser(
        description="Bulk create GitHub issues from a markdown file.",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Input file format (issues-to-create.md):
-----------------------------------------
# Issue Title One
Labels: bug, enhancement

This is the body of the first issue.
It can span multiple lines.

# Issue Title Two
Labels: documentation

Body of the second issue.
-----------------------------------------
All issues share the same project and milestone, configured at the top of this script
or passed via --project and --milestone flags.
        """
    )
    parser.add_argument(
        "--file", "-f",
        default=INPUT_FILE,
        help=f"Path to the markdown input file (default: {INPUT_FILE})"
    )
    parser.add_argument(
        "--project", "-p",
        default=DEFAULT_PROJECT_TITLE,
        help=f"GitHub Project title for all issues (default: {DEFAULT_PROJECT_TITLE})"
    )
    parser.add_argument(
        "--milestone", "-m",
        default=DEFAULT_MILESTONE,
        help=f"Milestone to assign to all issues (default: {DEFAULT_MILESTONE})"
    )
    parser.add_argument(
        "--no-project",
        action="store_true",
        help="Do not add issues to any project."
    )
    parser.add_argument(
        "--no-milestone",
        action="store_true",
        help="Do not assign a milestone to any issue."
    )
    parser.add_argument(
        "--repo", "-r",
        default=None,
        help="Target GitHub repo in OWNER/REPO format (uses gh default if not set)."
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Parse the file and print issues without creating them."
    )
    args = parser.parse_args()

    input_file = args.file
    project_title = args.project if not args.no_project else None
    milestone = args.milestone if not args.no_milestone else None

    print("🚀 Bulk GitHub Issue Creator")
    print("=" * 40)
    print(f"   Input file:     {input_file}")
    print(f"   Project:        {project_title or '(none)'}")
    print(f"   Milestone:      {milestone or '(none)'}")
    if args.repo:
        print(f"   Repo:           {args.repo}")
    if args.dry_run:
        print("   Mode:           DRY RUN (no issues will be created)")
    print("=" * 40)

    # --- Preflight checks ---
    if subprocess.run(["which", "gh"], capture_output=True).returncode != 0:
        print("❌ ERROR: GitHub CLI ('gh') is not installed or not in PATH.")
        print("   Install it from: https://cli.github.com/")
        exit(1)

    if not os.path.exists(input_file):
        print(f"❌ ERROR: Input file '{input_file}' not found.")
        exit(1)

    print("✅ Preflight checks passed.\n")

    # --- Parse ---
    print(f"📄 Parsing '{input_file}'...")
    with open(input_file, 'r') as f:
        content = f.read()

    issues = parse_issues(content)

    if not issues:
        print("⚠️  No issues found in the input file. Check the format.")
        exit(0)

    print(f"   Found {len(issues)} issue(s) to create.\n")

    # --- Create ---
    success_count = 0
    fail_count = 0

    for idx, issue in enumerate(issues, start=1):
        print(f"[{idx}/{len(issues)}] {issue['title']}")
        if issue['labels']:
            print(f"       Labels:    {', '.join(issue['labels'])}")
        print(f"       Milestone: {milestone or '(none)'}")
        print(f"       Project:   {project_title or '(none)'}")

        if args.dry_run:
            print("       (dry-run — skipping creation)\n")
            continue

        command = ["gh", "issue", "create"]
        if args.repo:
            command.extend(["--repo", args.repo])
        command.extend(["--title", issue["title"]])
        command.extend(["--body", issue["body"] or " "])  # gh requires non-empty body

        if project_title:
            command.extend(["--project", project_title])
        if milestone:
            command.extend(["--milestone", milestone])
        for label in issue["labels"]:
            command.extend(["--label", label])

        try:
            result = subprocess.run(command, check=True, text=True, capture_output=True)
            print(f"       ✅ Created: {result.stdout.strip()}")
            success_count += 1
        except subprocess.CalledProcessError as e:
            print(f"       ❌ Failed:  {e.stderr.strip()}")
            fail_count += 1

        print()

    # --- Summary ---
    print("=" * 40)
    if args.dry_run:
        print(f"🔍 Dry run complete. {len(issues)} issue(s) parsed, none created.")
    else:
        print(f"🎉 Done! {success_count} created, {fail_count} failed.")


if __name__ == "__main__":
    main()