#!/usr/bin/env python3
"""
PR Triage Automation — Categorize, deduplicate, and report on open PRs.

Usage:
    python scripts/pr_triage.py                    # Generate report
    python scripts/pr_triage.py --json             # JSON output
    python scripts/pr_triage.py --auto-merge       # Auto-merge safe PRs
    python scripts/pr_triage.py --repo timmy-home  # Single repo
"""

import json
import os
import re
import sys
from collections import Counter
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Optional

try:
    import urllib.request
except ImportError:
    print("Error: urllib not available")
    sys.exit(1)

# ---------------------------------------------------------------------------
# Config
# ---------------------------------------------------------------------------

GITEA_BASE = os.environ.get("GITEA_API_BASE", "https://forge.alexanderwhitestone.com/api/v1")
TOKEN_PATH = os.environ.get("GITEA_TOKEN_PATH", str(Path.home() / ".config/gitea/token"))
ORG = "Timmy_Foundation"

DEFAULT_REPOS = [
    "timmy-home",
    "hermes-agent",
    "timmy-config",
    "the-nexus",
    "the-door",
    "burn-fleet",
    "second-son-of-timmy",
]

# ---------------------------------------------------------------------------
# Categories
# ---------------------------------------------------------------------------

CATEGORY_RULES = {
    "training-data": [
        r"training[- ]?data", r"scene[- ]?description", r"dpo", r"training",
        r"batch[- ]?\d+", r"training[- ]?pipeline", r"jsonl",
    ],
    "bug-fix": [
        r"^fix[\(:]", r"\[BUG\]", r"\[FIX\]", r"bug fix", r"fixes #\d+",
        r"closes #\d+", r"broken", r"crash", r"regression",
    ],
    "feature": [
        r"^feat[\(:]", r"\[FEAT\]", r"\[FEATURE\]", r"new feature",
        r"add .+ support", r"implement",
    ],
    "docs": [
        r"^docs[\(:]", r"documentation", r"readme", r"genome",
    ],
    "security": [
        r"\[SECURITY\]", r"\[VITALIK\]", r"shield", r"injection",
        r"vulnerability", r"hardening",
    ],
    "infra": [
        r"\[INFRA\]", r"deploy", r"ansible", r"docker", r"ci[/ ]cd",
        r"cron", r"watchdog", r"systemd",
    ],
    "research": [
        r"research", r"benchmark", r"evaluation", r"analysis",
        r"\[BIG-BRAIN\]", r"investigate",
    ],
    "other": [],  # fallback
}


def categorize_pr(title: str, body: str) -> str:
    """Categorize a PR by its title and body."""
    text = f"{title} {body}".lower()
    for category, patterns in CATEGORY_RULES.items():
        if category == "other":
            continue
        for pattern in patterns:
            if re.search(pattern, text, re.IGNORECASE):
                return category
    return "other"


# ---------------------------------------------------------------------------
# Gitea API
# ---------------------------------------------------------------------------

def _load_token() -> str:
    try:
        return open(TOKEN_PATH).read().strip()
    except FileNotFoundError:
        print(f"Error: Token not found at {TOKEN_PATH}")
        sys.exit(1)


def api_get(path: str, token: str) -> Any:
    req = urllib.request.Request(f"{GITEA_BASE}{path}")
    req.add_header("Authorization", f"token {token}")
    resp = urllib.request.urlopen(req, timeout=30)
    return json.loads(resp.read())


def get_open_prs(repo: str, token: str) -> list[dict]:
    """Fetch all open PRs for a repo."""
    prs = []
    page = 1
    while True:
        try:
            batch = api_get(f"/repos/{ORG}/{repo}/pulls?state=open&limit=50&page={page}", token)
            if not batch:
                break
            prs.extend(batch)
            if len(batch) < 50:
                break
            page += 1
        except Exception:
            break
    return prs


def get_issue_state(repo: str, issue_num: int, token: str) -> Optional[str]:
    """Check if a referenced issue is still open."""
    try:
        issue = api_get(f"/repos/{ORG}/{repo}/issues/{issue_num}", token)
        return issue.get("state", "unknown")
    except Exception:
        return None


def find_referenced_issues(pr_body: str, pr_title: str) -> list[int]:
    """Extract issue numbers referenced in PR body/title."""
    text = f"{pr_title} {pr_body}"
    return [int(m) for m in re.findall(r'#(\d+)', text)]


def find_duplicates(prs: list[dict]) -> list[tuple[dict, dict]]:
    """Find PRs that reference the same issue."""
    issue_to_prs: dict[int, list[dict]] = {}
    for pr in prs:
        refs = find_referenced_issues(pr.get("body", ""), pr.get("title", ""))
        for issue_num in refs:
            issue_to_prs.setdefault(issue_num, []).append(pr)

    duplicates = []
    for issue_num, pr_list in issue_to_prs.items():
        if len(pr_list) > 1:
            # Pair up duplicates
            for i in range(len(pr_list)):
                for j in range(i + 1, len(pr_list)):
                    duplicates.append((pr_list[i], pr_list[j]))

    return duplicates


# ---------------------------------------------------------------------------
# Triage
# ---------------------------------------------------------------------------

def triage_repo(repo: str, token: str) -> dict:
    """Triage all open PRs for a repo."""
    prs = get_open_prs(repo, token)

    categorized: dict[str, list[dict]] = {}
    stale_issues = []
    duplicates = find_duplicates(prs)

    for pr in prs:
        category = categorize_pr(pr.get("title", ""), pr.get("body", ""))
        categorized.setdefault(category, []).append(pr)

        # Check referenced issues
        refs = find_referenced_issues(pr.get("body", ""), pr.get("title", ""))
        for issue_num in refs:
            state = get_issue_state(repo, issue_num, token)
            if state == "closed":
                stale_issues.append({"pr": pr["number"], "issue": issue_num, "repo": repo})

    return {
        "repo": repo,
        "total_prs": len(prs),
        "by_category": {k: len(v) for k, v in categorized.items()},
        "categorized": categorized,
        "duplicates": [(a["number"], b["number"]) for a, b in duplicates],
        "stale_issues": stale_issues,
    }


def triage_all(repos: list[str], token: str) -> list[dict]:
    """Triage all repos."""
    results = []
    for repo in repos:
        print(f"  Triaging {repo}...", file=sys.stderr)
        try:
            result = triage_repo(repo, token)
            results.append(result)
        except Exception as e:
            print(f"  Error triaging {repo}: {e}", file=sys.stderr)
            results.append({"repo": repo, "error": str(e)})
    return results


# ---------------------------------------------------------------------------
# Report
# ---------------------------------------------------------------------------

def generate_markdown_report(results: list[dict]) -> str:
    """Generate a markdown triage report."""
    total_prs = sum(r.get("total_prs", 0) for r in results)
    all_categories: Counter = Counter()
    all_duplicates = []
    all_stale = []

    for r in results:
        for cat, count in r.get("by_category", {}).items():
            all_categories[cat] += count
        all_duplicates.extend(r.get("duplicates", []))
        all_stale.extend(r.get("stale_issues", []))

    lines = [
        "# PR Triage Report",
        "",
        f"Generated: {datetime.now(timezone.utc).strftime('%Y-%m-%d %H:%M UTC')}",
        "",
        "## Summary",
        "",
        f"| Metric | Count |",
        f"|--------|-------|",
        f"| Total open PRs | {total_prs} |",
        f"| Repos scanned | {len(results)} |",
        f"| Duplicates found | {len(all_duplicates)} |",
        f"| Stale (issue closed) | {len(all_stale)} |",
        "",
        "## By Category",
        "",
        "| Category | Count |",
        "|----------|-------|",
    ]

    for cat, count in all_categories.most_common():
        lines.append(f"| {cat} | {count} |")

    if all_duplicates:
        lines.extend(["", "## Duplicates (same issue referenced)", ""])
        for a, b in all_duplicates:
            lines.append(f"- PR #{a} and PR #{b}")

    if all_stale:
        lines.extend(["", "## Stale PRs (referenced issue is closed)", ""])
        for s in all_stale:
            lines.append(f"- {s['repo']} PR #{s['pr']} → issue #{s['issue']} (closed)")

    # Per-repo detail
    for r in results:
        if r.get("error"):
            lines.extend(["", f"## {r['repo']} — ERROR", "", f"```{r['error']}```"])
            continue

        lines.extend([f"", f"## {r['repo']} ({r.get('total_prs', 0)} open PRs)", ""])
        for cat, prs in r.get("categorized", {}).items():
            if not prs:
                continue
            lines.append(f"