#!/bin/bash
# Wrapper script that auto-restarts uvicorn on crash
# Usage: ./run-with-restart.sh [port] [log_file]

# Get script directory and activate venv
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/venv/bin/activate"

PORT=${1:-8000}
LOG_FILE=${2:-/tmp/unified_backend.log}
MAX_RESTARTS=10
RESTART_COUNT=0
RESTART_DELAY=3
UVICORN_PID=""

# On SIGTERM or SIGINT: kill uvicorn child and exit cleanly (no restart)
cleanup_and_exit() {
    echo "[Backend Runner] Received termination signal, stopping..." | tee -a "$LOG_FILE"
    if [ -n "$UVICORN_PID" ] && kill -0 "$UVICORN_PID" 2>/dev/null; then
        kill "$UVICORN_PID" 2>/dev/null
        wait "$UVICORN_PID" 2>/dev/null
    fi
    exit 0
}
trap cleanup_and_exit SIGTERM SIGINT

echo "[Backend Runner] Starting uvicorn with auto-restart (max $MAX_RESTARTS restarts)" | tee -a "$LOG_FILE"
echo "[Backend Runner] Port: $PORT, Log: $LOG_FILE" | tee -a "$LOG_FILE"

while [ $RESTART_COUNT -lt $MAX_RESTARTS ]; do
    START_TIME=$(date +%s)
    echo "" | tee -a "$LOG_FILE"
    echo "[Backend Runner] $(date '+%Y-%m-%d %H:%M:%S') - Starting uvicorn (attempt $((RESTART_COUNT + 1))/$MAX_RESTARTS)..." | tee -a "$LOG_FILE"

    # Run uvicorn in background so we can track its PID and trap signals properly
    uvicorn main:app --host 0.0.0.0 --port "$PORT" >> "$LOG_FILE" 2>&1 &
    UVICORN_PID=$!

    # Wait for uvicorn to exit
    wait "$UVICORN_PID"
    EXIT_CODE=$?
    UVICORN_PID=""

    END_TIME=$(date +%s)
    RUNTIME=$((END_TIME - START_TIME))

    echo "[Backend Runner] $(date '+%Y-%m-%d %H:%M:%S') - uvicorn exited with code $EXIT_CODE after ${RUNTIME}s" | tee -a "$LOG_FILE"

    # Exit if trap already fired (cleanup_and_exit sets UVICORN_PID="")
    # or if uvicorn exited due to a signal (130=SIGINT, 143=SIGTERM, 137=SIGKILL)
    if [ $EXIT_CODE -eq 130 ] || [ $EXIT_CODE -eq 143 ] || [ $EXIT_CODE -eq 137 ]; then
        echo "[Backend Runner] Received termination signal (code $EXIT_CODE), exiting..." | tee -a "$LOG_FILE"
        exit 0
    fi

    # If it ran for more than 60 seconds, reset restart counter (was stable)
    if [ $RUNTIME -gt 60 ]; then
        RESTART_COUNT=0
        echo "[Backend Runner] Process was stable (>${RUNTIME}s), resetting restart counter" | tee -a "$LOG_FILE"
    else
        RESTART_COUNT=$((RESTART_COUNT + 1))
        echo "[Backend Runner] Quick crash detected, restart count: $RESTART_COUNT/$MAX_RESTARTS" | tee -a "$LOG_FILE"
    fi

    # Wait before restart
    if [ $RESTART_COUNT -lt $MAX_RESTARTS ]; then
        echo "[Backend Runner] Restarting in ${RESTART_DELAY}s..." | tee -a "$LOG_FILE"
        sleep $RESTART_DELAY
    fi
done

echo "[Backend Runner] Max restarts ($MAX_RESTARTS) reached. Giving up." | tee -a "$LOG_FILE"
exit 1