#!/usr/bin/env python3
"""
Pull Request Review Script
Reviews all pull requests and creates a comprehensive summary
"""

import subprocess
import sys
import json
from pathlib import Path
from datetime import datetime
from collections import defaultdict

REPO_ROOT = Path(__file__).resolve().parents[1]


def run_command(cmd, capture_output=True, silent=False):
    """Run a command and return the result."""
    try:
        result = subprocess.run(
            cmd,
            cwd=REPO_ROOT,
            capture_output=capture_output,
            text=True,
            timeout=30,
            encoding='utf-8',
            errors='replace'
        )
        return result
    except FileNotFoundError:
        # Silently handle missing executables if requested
        if not silent:
            print(f"Error: Command not found: {cmd[0]}", file=sys.stderr)
        return None
    except Exception as e:
        if not silent:
            print(f"Error running command: {e}", file=sys.stderr)
        return None


# --- ⚡ Bolt: Global cache for branch metadata to avoid redundant git calls.
BRANCH_METADATA = {}


def get_all_branch_metadata():
    """⚡ Bolt: Fetch metadata for all remote branches in a single git call."""
    # Format: branch|ahead-behind|date|subject
    # ahead-behind gives "ahead behind" relative to main
    fmt = "%(refname:short)|%(ahead-behind:main)|%(committerdate:iso8601)|%(subject)"
    result = run_command(["git", "for-each-ref", f"--format={fmt}", "refs/remotes/origin"])

    if not result or result.returncode != 0:
        return {}

    metadata = {}
    for line in result.stdout.strip().split('\n'):
        if not line:
            continue
        try:
            # Handle potential pipes in subjects by splitting only on the first 3 pipes
            parts = line.split('|', 3)
            if len(parts) < 3:
                continue

            branch = parts[0]
            # Filter out HEAD and origin/main
            if branch in ["origin/HEAD", "origin/main", "origin"]:
                continue

            ab = parts[1].split()
            ahead = int(ab[0]) if len(ab) >= 1 and ab[0].isdigit() else 0
            behind = int(ab[1]) if len(ab) >= 2 and ab[1].isdigit() else 0

            metadata[branch] = {
                "ahead": ahead,
                "behind": behind,
                "date": parts[2] if len(parts) > 2 else "Unknown",
                "subject": parts[3] if len(parts) > 3 else "No subject"
            }
        except Exception:
            continue

    return metadata


def get_prs_via_gh_cli():
    """Get PRs using GitHub CLI."""
    # ⚡ Bolt: Run gh silently as it might not be installed.
    result = run_command(["gh", "pr", "list", "--state", "all", "--json", "number,title,state,author,createdAt,updatedAt,headRefName,baseRefName,isDraft,labels"], silent=True)
    if result and result.returncode == 0:
        try:
            return json.loads(result.stdout)
        except json.JSONDecodeError:
            return []
    return None


def get_prs_via_git():
    """Get PR information via git branches."""
    # ⚡ Bolt: Populate global metadata cache once.
    global BRANCH_METADATA
    BRANCH_METADATA = get_all_branch_metadata()
    
    # ⚡ Bolt: Identify open and merged branches using the pre-fetched metadata.
    # A branch is "open" if it has commits not in main (ahead > 0).
    # A branch is "merged" if it has no commits ahead of main (ahead == 0).
    branches = []
    merged_branches = []
    
    for branch, data in BRANCH_METADATA.items():
        if data["ahead"] > 0:
            branches.append(branch)
        else:
            merged_branches.append(branch)

    return {
        "open": sorted(branches),
        "merged": sorted(merged_branches)
    }


def analyze_branch_name(branch_name):
    """Analyze branch name to extract PR information."""
    branch = branch_name.replace("origin/", "")
    
    info = {
        "type": "unknown",
        "category": "other",
        "description": branch
    }
    
    # Categorize branches
    if branch.startswith("Cursor/"):
        info["type"] = "cursor"
        info["category"] = "ai-generated"
        info["description"] = branch.replace("Cursor/A6-9V/", "")
    elif branch.startswith("copilot/"):
        info["type"] = "copilot"
        info["category"] = "ai-generated"
        info["description"] = branch.replace("copilot/", "")
    elif branch.startswith("bolt-"):
        info["type"] = "bolt"
        info["category"] = "optimization"
        info["description"] = branch.replace("bolt-", "")
    elif branch.startswith("feat/"):
        info["type"] = "feature"
        info["category"] = "feature"
        info["description"] = branch.replace("feat/", "")
    elif branch.startswith("feature/"):
        info["type"] = "feature"
        info["category"] = "feature"
        info["description"] = branch.replace("feature/", "")
    
    return info


def get_branch_info(branch_name):
    """Get detailed information about a branch."""
    branch = branch_name.replace("origin/", "")
    
    # ⚡ Bolt: Use pre-fetched metadata instead of calling git log.
    data = BRANCH_METADATA.get(branch_name, {})
    
    commit_count = data.get("ahead", 0)
    last_commit = data.get("date")
    subject = data.get("subject", "No subject")
    
    return {
        "branch": branch,
        "full_name": branch_name,
        "commit_count": commit_count,
        "commits": [f"N/A {subject}"], # Only the latest subject is available in this optimized path
        "last_commit_date": last_commit
    }


def main():
    """Main review function."""
    print("=" * 80)
    print("PULL REQUEST REVIEW")
    print(f"Generated: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}")
    print("=" * 80)
    print()
    
    # Try GitHub CLI first
    prs = get_prs_via_gh_cli()
    
    if prs is not None:
        print(f"Found {len(prs)} pull requests via GitHub CLI")
        print()
        
        # Group by state
        by_state = defaultdict(list)
        for pr in prs:
            by_state[pr.get("state", "unknown")].append(pr)
        
        print("Pull Requests by State:")
        for state, pr_list in sorted(by_state.items()):
            print(f"  {state.upper()}: {len(pr_list)}")
        print()
        
        # Show open PRs
        open_prs = by_state.get("OPEN", [])
        if open_prs:
            print("=" * 80)
            print("OPEN PULL REQUESTS")
            print("=" * 80)
            for pr in open_prs:
                print(f"\nPR #{pr.get('number', 'N/A')}: {pr.get('title', 'No title')}")
                print(f"  Author: {pr.get('author', {}).get('login', 'Unknown')}")
                print(f"  Branch: {pr.get('headRefName', 'N/A')} -> {pr.get('baseRefName', 'main')}")
                print(f"  Created: {pr.get('createdAt', 'N/A')}")
                print(f"  Updated: {pr.get('updatedAt', 'N/A')}")
                print(f"  Draft: {'Yes' if pr.get('isDraft') else 'No'}")
                labels = [l.get('name') for l in pr.get('labels', [])]
                if labels:
                    print(f"  Labels: {', '.join(labels)}")
        
        # Show merged PRs
        merged_prs = by_state.get("MERGED", [])
        if merged_prs:
            print("\n" + "=" * 80)
            print(f"MERGED PULL REQUESTS ({len(merged_prs)} total)")
            print("=" * 80)
            print(f"\nShowing last 10 merged PRs:")
            for pr in merged_prs[-10:]:
                print(f"  PR #{pr.get('number', 'N/A')}: {pr.get('title', 'No title')}")
    
    else:
        # Fallback to git branch analysis
        print("GitHub CLI not available, analyzing branches...")
        print()
        
        branch_info = get_prs_via_git()
        
        open_branches = branch_info["open"]
        merged_branches = branch_info["merged"]
        
        print(f"Open branches (potential PRs): {len(open_branches)}")
        print(f"Merged branches (completed PRs): {len(merged_branches)}")
        print()
        
        # Categorize open branches
        categories = defaultdict(list)
        for branch in open_branches:
            info = analyze_branch_name(branch)
            categories[info["category"]].append((branch, info))
        
        print("=" * 80)
        print("OPEN BRANCHES (Potential Pull Requests)")
        print("=" * 80)
        print()
        
        for category, branches in sorted(categories.items()):
            print(f"{category.upper()}: {len(branches)} branches")
            for branch, info in branches[:10]:  # Show first 10
                branch_details = get_branch_info(branch)
                print(f"  - {info['description']}")
                print(f"    Branch: {branch_details['branch']}")
                print(f"    Commits: {branch_details['commit_count']}")
                if branch_details['last_commit_date']:
                    print(f"    Last commit: {branch_details['last_commit_date']}")
            if len(branches) > 10:
                print(f"    ... and {len(branches) - 10} more")
            print()
        
        print("=" * 80)
        print("MERGED BRANCHES (Completed Pull Requests)")
        print("=" * 80)
        print(f"\nTotal merged: {len(merged_branches)}")
        print("\nRecent merged branches:")
        for branch in merged_branches[:20]:
            info = analyze_branch_name(branch)
            print(f"  - {info['description']}")
    
    print("\n" + "=" * 80)
    print("REVIEW COMPLETE")
    print("=" * 80)
    print("\nNote: GitHub doesn't support 'pinning' pull requests directly.")
    print("Consider:")
    print("1. Creating a tracking issue for important PRs")
    print("2. Using labels to categorize PRs")
    print("3. Adding PRs to project boards")
    print("4. Creating a PR summary document")


if __name__ == "__main__":
    main()