#!/usr/bin/env python3
from __future__ import annotations

import json
import re
import sys
from collections import OrderedDict
from pathlib import Path


def uniq(items: list[str]) -> list[str]:
    return list(OrderedDict((item, None) for item in items if item))


def extract_texts(obj) -> list[str]:
    texts: list[str] = []
    if isinstance(obj, dict):
        if obj.get("type") in {"input_text", "output_text"} and isinstance(obj.get("text"), str):
            texts.append(obj["text"])
        for value in obj.values():
            texts.extend(extract_texts(value))
    elif isinstance(obj, list):
        for value in obj:
            texts.extend(extract_texts(value))
    return texts


def main() -> int:
    if len(sys.argv) not in {2, 3}:
        print("usage: session_to_memory.py SESSION_JSONL [OUTPUT_MD]", file=sys.stderr)
        return 2

    session_path = Path(sys.argv[1]).expanduser().resolve()
    output_path = Path(sys.argv[2]).expanduser().resolve() if len(sys.argv) == 3 else session_path.with_suffix(".memory.md")

    user_texts: list[str] = []
    assistant_texts: list[str] = []
    paths: list[str] = []
    session_meta = {}

    path_pattern = re.compile(r"(\/[A-Za-z0-9._ \-\/]+)")

    with session_path.open() as handle:
        for raw_line in handle:
            raw_line = raw_line.strip()
            if not raw_line:
                continue
            event = json.loads(raw_line)
            payload = event.get("payload", {})
            if event.get("type") == "session_meta":
                session_meta = payload
            if event.get("type") == "response_item" and payload.get("type") == "message":
                role = payload.get("role")
                texts = extract_texts(payload.get("content", []))
                if role == "user":
                    user_texts.extend(texts)
                elif role == "assistant":
                    assistant_texts.extend(texts)
                for text in texts:
                    paths.extend(path_pattern.findall(text))

    user_texts = uniq([text.strip() for text in user_texts if text.strip()])
    assistant_texts = uniq([text.strip() for text in assistant_texts if text.strip()])
    paths = uniq([path.strip() for path in paths if path.strip()])

    output = []
    output.append(f"# Session Memory Draft")
    output.append("")
    output.append(f"- Session file: `{session_path}`")
    if session_meta.get("timestamp"):
        output.append(f"- Session timestamp: `{session_meta['timestamp']}`")
    if session_meta.get("cwd"):
        output.append(f"- Working directory: `{session_meta['cwd']}`")
    output.append("")
    output.append("## User Requests")
    output.append("")
    for text in user_texts[:20]:
        output.append(f"- {text.replace(chr(10), ' ')}")
    output.append("")
    output.append("## Candidate Paths Mentioned")
    output.append("")
    for path in paths[:30]:
        output.append(f"- `{path}`")
    output.append("")
    output.append("## Assistant Notes To Distill")
    output.append("")
    output.append("- Copy only stable preferences, project facts, and durable decisions into your memory markdown files.")
    output.append("- Do not copy transient debugging output or large transcript excerpts.")
    output.append("- Summarize in your own words before adding to long-term memory.")
    output.append("")
    output.append("## Sample Durable Summary")
    output.append("")
    output.append("- Project:")
    output.append("- User preference:")
    output.append("- Important decision:")
    output.append("- Follow-up worth remembering:")
    output.append("")
    output.append("## Assistant Messages Snapshot")
    output.append("")
    for text in assistant_texts[:10]:
        output.append(f"- {text.replace(chr(10), ' ')}")

    output_path.write_text("\n".join(output) + "\n")
    print(output_path)
    return 0


if __name__ == "__main__":
    raise SystemExit(main())