"""
Replay API — start/step/seek/reset replay sessions against the timeline journal.
"""

from fastapi import APIRouter
from pydantic import BaseModel
from typing import Optional, Any, Dict

from backend.analysis.timeline_store import STORE as TIMELINE_STORE
from backend.session.db import SessionDB

router = APIRouter(prefix="/replay", tags=["replay"])

# Process-wide session DB (now SQLite-backed)
SESSION_DB = SessionDB()


class StartReplayBody(BaseModel):
    journal: Optional[str] = None  # session id or "latest"
    session_id: Optional[str] = None


# -------------------------
# START REPLAY SESSION
# -------------------------
@router.post("/start")
def start_replay(body: StartReplayBody):
    """Start a new replay session. Snapshots the current live timeline
    into a new session id, so the session has its own immutable event list."""

    import uuid

    # Create the session first with a placeholder, then patch the source
    sid = SESSION_DB.create_session(body.journal or "live")

    # Snapshot the current live timeline into the session
    events = TIMELINE_STORE.all()

    # Log each event into the session so SESSION_DB.get_replay_stream(sid)
    # returns them (and the autopsy endpoint can find them)
    for event in events:
        # Don't double-store — just create a reference event
        SESSION_DB.log_event(sid, event.get("type", "event"), event)

    return {
        "session_id": sid,
        "event_count": len(events),
        "events_available": len(events),
    }


# -------------------------
# GET EVENTS (full journal snapshot)
# -------------------------
@router.get("/events")
def get_events():
    """Return the full current journal. Used by the replay UI on load."""
    return {"events": TIMELINE_STORE.all()}


# -------------------------
# GET EVENTS FOR A SPECIFIC SESSION
# -------------------------
@router.get("/events/{session_id}")
def get_session_events(session_id: str):
    return {"session_id": session_id, "events": SESSION_DB.get_replay_stream(session_id)}


# -------------------------
# STEP FORWARD
# -------------------------
@router.post("/step")
def replay_step(session_id: str):
    events = SESSION_DB.get_replay_stream(session_id)
    return {
        "session_id": session_id,
        "event_count": len(events),
        "events": events[:1],
    }


# -------------------------
# SEEK
# -------------------------
@router.post("/seek")
def replay_seek(session_id: str, timestamp: float):
    events = SESSION_DB.get_replay_stream(session_id)
    best = None
    for e in events:
        ts = e.get("ts") or e.get("timestamp") or 0
        if ts <= timestamp:
            best = e
        else:
            break
    return {"event": best, "session_id": session_id}


# -------------------------
# RESET
# -------------------------
@router.post("/reset")
def replay_reset(session_id: str):
    events = SESSION_DB.get_replay_stream(session_id)
    return {
        "session_id": session_id,
        "event": events[0] if events else None,
        "event_count": len(events),
    }


# -------------------------
# Convenience: replay_endpoint wrapper for api.py facade
# -------------------------
def replay_endpoint(session_id, registry=None):
    """Legacy wrapper — returns the session events for a given id."""
    return {
        "session_id": session_id,
        "events": SESSION_DB.get_replay_stream(session_id),
    }