#!/usr/bin/env python3
"""
Browse and analyze session history.
Usage: python3 history-browser.py [--list|--show <id>|--stats|--unsummarized]
"""

import argparse
import json
import sys
from datetime import datetime
from pathlib import Path
from typing import Dict, List, Optional

CLAUDE_DIR = Path.home() / ".claude"
HISTORY_DIR = CLAUDE_DIR / "state" / "personal-assistant" / "history"


def load_index() -> Optional[Dict]:
    """Load history index."""
    index_path = HISTORY_DIR / "index.json"
    try:
        with open(index_path) as f:
            return json.load(f)
    except (FileNotFoundError, json.JSONDecodeError):
        return None


def list_sessions(limit: int = 20, show_all: bool = False):
    """List recent sessions."""
    index = load_index()
    if not index or "sessions" not in index:
        print("No sessions found.")
        return

    sessions = index["sessions"]
    if not show_all:
        sessions = sessions[-limit:]

    print(f"\n📜 Session History ({len(sessions)} of {len(index['sessions'])} total)\n")
    print(f"{'ID':<12} {'Date':<12} {'Summarized':<12} {'Topics'}")
    print("-" * 70)

    for session in reversed(sessions):
        sid = session.get("id", "unknown")[:10]
        date = session.get("date", "unknown")[:10]
        summarized = "✓" if session.get("summarized", False) else "○"
        topics = ", ".join(session.get("topics", [])[:3])
        if len(session.get("topics", [])) > 3:
            topics += "..."

        print(f"{sid:<12} {date:<12} {summarized:<12} {topics}")

    print("")


def show_session(session_id: str):
    """Show details for a specific session."""
    index = load_index()
    if not index or "sessions" not in index:
        print("No sessions found.")
        return

    # Find session by ID prefix
    session = None
    for s in index["sessions"]:
        if s.get("id", "").startswith(session_id):
            session = s
            break

    if not session:
        print(f"Session '{session_id}' not found.")
        return

    print(f"\n📜 Session: {session.get('id', 'unknown')}")
    print(f"   Date: {session.get('date', 'unknown')}")
    print(f"   Summarized: {'Yes' if session.get('summarized') else 'No'}")
    print(f"\n   Topics:")
    for topic in session.get("topics", []):
        print(f"     - {topic}")
    print(f"\n   Summary:")
    print(f"     {session.get('summary', 'No summary available')}")

    # Check for associated JSONL file
    jsonl_path = HISTORY_DIR / f"{session.get('id', '')}.jsonl"
    if jsonl_path.exists():
        print(f"\n   Log file: {jsonl_path}")
        try:
            with open(jsonl_path) as f:
                lines = f.readlines()
                print(f"   Log entries: {len(lines)}")
        except Exception:
            pass
    print("")


def show_stats():
    """Show session statistics."""
    index = load_index()
    if not index or "sessions" not in index:
        print("No sessions found.")
        return

    sessions = index["sessions"]
    total = len(sessions)
    summarized = sum(1 for s in sessions if s.get("summarized", False))
    unsummarized = total - summarized

    # Topic frequency
    topic_counts: Dict[str, int] = {}
    for s in sessions:
        for topic in s.get("topics", []):
            topic_counts[topic] = topic_counts.get(topic, 0) + 1

    top_topics = sorted(topic_counts.items(), key=lambda x: x[1], reverse=True)[:10]

    # Date range
    dates = [s.get("date", "") for s in sessions if s.get("date")]
    oldest = min(dates)[:10] if dates else "N/A"
    newest = max(dates)[:10] if dates else "N/A"

    print(f"\n📊 Session Statistics\n")
    print(f"   Total sessions: {total}")
    print(f"   Summarized: {summarized}")
    print(f"   Pending summary: {unsummarized}")
    print(f"   Date range: {oldest} to {newest}")
    print(f"\n   Top Topics:")
    for topic, count in top_topics:
        bar = "█" * min(count, 20)
        print(f"     {topic:<30} {bar} ({count})")
    print("")


def list_unsummarized():
    """List sessions that need summarization."""
    index = load_index()
    if not index or "sessions" not in index:
        print("No sessions found.")
        return

    unsummarized = [s for s in index["sessions"] if not s.get("summarized", False)]

    if not unsummarized:
        print("\n✓ All sessions are summarized!\n")
        return

    print(f"\n⚠ Unsummarized Sessions ({len(unsummarized)})\n")
    print(f"{'ID':<12} {'Date':<12} {'Topics'}")
    print("-" * 60)

    for session in unsummarized:
        sid = session.get("id", "unknown")[:10]
        date = session.get("date", "unknown")[:10]
        topics = ", ".join(session.get("topics", [])[:3]) or "No topics"

        print(f"{sid:<12} {date:<12} {topics}")

    print(f"\nRun /summarize to process these sessions.\n")


def main():
    parser = argparse.ArgumentParser(description="Browse session history")
    parser.add_argument("--list", "-l", action="store_true", help="List recent sessions")
    parser.add_argument("--all", "-a", action="store_true", help="Show all sessions (with --list)")
    parser.add_argument("--show", "-s", type=str, help="Show session details by ID")
    parser.add_argument("--stats", action="store_true", help="Show statistics")
    parser.add_argument("--unsummarized", "-u", action="store_true",
                       help="List unsummarized sessions")
    parser.add_argument("--limit", "-n", type=int, default=20,
                       help="Number of sessions to show (default: 20)")

    args = parser.parse_args()

    if args.show:
        show_session(args.show)
    elif args.stats:
        show_stats()
    elif args.unsummarized:
        list_unsummarized()
    elif args.list or not any([args.show, args.stats, args.unsummarized]):
        list_sessions(limit=args.limit, show_all=args.all)


if __name__ == "__main__":
    main()