#!/bin/bash
set -euo pipefail

# Phase 6, Plan 1: Standalone Server Start Script
# Usage: ./start_server.sh
# Purpose: Start backend and frontend servers without Docker
# Requirements: Python 3.12+, Node.js 20+, and dependencies installed

# Color output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

log_info() { echo -e "${BLUE}[INFO]${NC} $1"; }
log_success() { echo -e "${GREEN}[SUCCESS]${NC} $1"; }
log_warn() { echo -e "${YELLOW}[WARN]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; exit 1; }

log_info "=== TFM aInventory Standalone Server Start ==="

# ============================================================================
# STEP 1: Pre-flight checks
# ============================================================================
log_info "Step 1/7: Running pre-flight checks..."

# Check Python version
command -v python3 &> /dev/null || log_error "Python 3 not installed"
PYTHON_VERSION=$(python3 --version 2>&1 | awk '{print $2}')
log_success "  ✓ Python $PYTHON_VERSION found"

# Check Node.js version
command -v node &> /dev/null || log_error "Node.js not installed"
NODE_VERSION=$(node --version)
log_success "  ✓ Node.js $NODE_VERSION found"

# Check required files
[[ -f "inventory.env" ]] || log_error "inventory.env not found. Copy from inventory.env.template"
log_success "  ✓ inventory.env found"

[[ -d "backend" ]] || log_error "backend/ directory not found"
log_success "  ✓ backend/ directory found"

[[ -d "frontend" ]] || log_error "frontend/ directory not found"
log_success "  ✓ frontend/ directory found"

# ============================================================================
# STEP 2: Load environment
# ============================================================================
log_info "Step 2/7: Loading environment configuration..."

source inventory.env

BACKEND_PORT=${BACKEND_PORT:-8000}
FRONTEND_PORT=${FRONTEND_PORT:-3000}
DATA_DIR=${DATA_DIR:-./data}
LOGS_DIR=${LOGS_DIR:-./logs}
LOG_LEVEL=${LOG_LEVEL:-INFO}

log_success "  ✓ Environment loaded (Backend: $BACKEND_PORT, Frontend: $FRONTEND_PORT)"

# ============================================================================
# STEP 3: Prepare directories
# ============================================================================
log_info "Step 3/7: Preparing data and log directories..."

mkdir -p "$DATA_DIR" "$LOGS_DIR"
mkdir -p "$DATA_DIR/temp"
chmod -R 755 "$DATA_DIR" "$LOGS_DIR"

log_success "  ✓ Directories ready"

# ============================================================================
# STEP 4: Check port availability
# ============================================================================
log_info "Step 4/7: Checking port availability..."

for port in $BACKEND_PORT $FRONTEND_PORT; do
  if command -v netstat &> /dev/null; then
    if netstat -tuln 2>/dev/null | grep -q ":$port "; then
      log_error "Port $port is already in use. Stop the application using it or change the port."
    fi
  else
    log_warn "  netstat not available; skipping port check"
  fi
done

log_success "  ✓ Required ports are available"

# ============================================================================
# STEP 5: Start backend server
# ============================================================================
log_info "Step 5/7: Starting backend API server..."

# Create backend log file
BACKEND_LOG="$LOGS_DIR/backend.log"
touch "$BACKEND_LOG"

# Start backend in background
cd backend || log_error "Failed to enter backend directory"

if [[ ! -f "requirements.txt" ]]; then
  log_error "backend/requirements.txt not found"
fi

# Create and use Python virtual environment in project root
VENV_DIR=".venv"
if [[ ! -d "$VENV_DIR" ]]; then
  log_info "  Creating Python virtual environment..."
  cd - > /dev/null || true  # Return to project root
  python3 -m venv "$VENV_DIR" || log_error "Failed to create virtual environment"
  cd backend || log_error "Failed to enter backend directory"
fi

# Activate virtual environment (from project root)
source "../$VENV_DIR/bin/activate"

# Install dependencies if needed
if ! python3 -c "import fastapi" &> /dev/null; then
  log_info "  Installing Python dependencies..."
  pip install -q -r requirements.txt || log_error "Failed to install backend dependencies"
fi

# Initialize database if needed
if [[ ! -f "../$DATA_DIR/inventory.db" ]]; then
  log_info "  Initializing database..."
  python3 -c "from db_manager import init_db; init_db()" || true
fi

# Start uvicorn in background (with proper working directory)
log_info "  Starting uvicorn server..."
(cd "$(pwd)" && python3 -m uvicorn main:app --host 0.0.0.0 --port "$BACKEND_PORT" --log-level "${LOG_LEVEL,,}" >> "$BACKEND_LOG" 2>&1) &
BACKEND_PID=$!

log_success "  ✓ Backend started (PID: $BACKEND_PID, Port: $BACKEND_PORT)"

cd - > /dev/null || true

# ============================================================================
# STEP 6: Start frontend server
# ============================================================================
log_info "Step 6/7: Starting frontend web server..."

FRONTEND_LOG="$LOGS_DIR/frontend.log"
touch "$FRONTEND_LOG"

cd frontend || log_error "Failed to enter frontend directory"

if [[ ! -f "package.json" ]]; then
  log_error "frontend/package.json not found"
fi

# Install dependencies if needed
if [[ ! -d "node_modules" ]]; then
  log_info "  Installing npm dependencies..."
  npm ci --silent || log_error "Failed to install frontend dependencies"
fi

# Build Next.js if not already built
if [[ ! -d ".next" ]]; then
  log_info "  Building Next.js application..."
  npm run build || log_error "Failed to build frontend"
fi

# Start Next.js in production mode (with proper working directory)
log_info "  Starting Next.js server..."
FRONTEND_DIR="$(pwd)"
(cd "$FRONTEND_DIR" && PORT="$FRONTEND_PORT" node .next/standalone/server.js >> "$FRONTEND_LOG" 2>&1) &
FRONTEND_PID=$!

log_success "  ✓ Frontend started (PID: $FRONTEND_PID, Port: $FRONTEND_PORT)"

cd - > /dev/null || true

# ============================================================================
# STEP 7: Verify services
# ============================================================================
log_info "Step 7/7: Verifying services..."

# Wait a few seconds for services to start
sleep 3

# Check backend
if curl -sf "http://localhost:${BACKEND_PORT}/health" &> /dev/null; then
  log_success "  ✓ Backend API responding at http://localhost:${BACKEND_PORT}/health"
else
  log_warn "  Backend not responding yet; it may still be initializing"
fi

# Check frontend
if curl -sf "http://localhost:${FRONTEND_PORT}/" &> /dev/null; then
  log_success "  ✓ Frontend responding at http://localhost:${FRONTEND_PORT}"
else
  log_warn "  Frontend not responding yet; it may still be initializing"
fi

# ============================================================================
# Summary and instructions
# ============================================================================
echo ""
echo -e "${GREEN}╔════════════════════════════════════════════════════════════╗${NC}"
echo -e "${GREEN}║${NC}  Standalone servers started successfully!               ${GREEN}║${NC}"
echo -e "${GREEN}╚════════════════════════════════════════════════════════════╝${NC}"
echo ""
echo "Access points:"
echo "  Frontend:   http://localhost:${FRONTEND_PORT}"
echo "  Backend:    http://localhost:${BACKEND_PORT}"
echo "  API Docs:   http://localhost:${BACKEND_PORT}/docs"
echo ""
echo "Process IDs:"
echo "  Backend:    $BACKEND_PID"
echo "  Frontend:   $FRONTEND_PID"
echo ""
echo "Log files:"
echo "  Backend:    $BACKEND_LOG"
echo "  Frontend:   $FRONTEND_LOG"
echo ""
echo "Monitoring:"
echo "  Backend:    tail -f $BACKEND_LOG"
echo "  Frontend:   tail -f $FRONTEND_LOG"
echo "  All logs:   tail -f $LOGS_DIR/*.log"
echo ""
echo "To stop servers:"
echo "  kill $BACKEND_PID $FRONTEND_PID"
echo ""
log_success "Servers are running!"

# Keep script running indefinitely and handle signals
trap "log_info 'Received interrupt signal'; kill $BACKEND_PID $FRONTEND_PID 2>/dev/null || true; exit 0" SIGINT SIGTERM

# Monitor processes - restart if they crash
while true; do
  if ! kill -0 $BACKEND_PID 2>/dev/null; then
    log_warn "Backend process died (PID $BACKEND_PID), monitoring stopped"
  fi
  if ! kill -0 $FRONTEND_PID 2>/dev/null; then
    log_warn "Frontend process died (PID $FRONTEND_PID), monitoring stopped"
  fi
  sleep 5
done