#!/bin/bash
# Script to migrate data from SQLite to PostgreSQL

set -e

echo "🔄 Starting SQLite to PostgreSQL Migration..."

# Check if SQLite database exists
SQLITE_DB="./backEnd/db.sqlite3"
if [ ! -f "$SQLITE_DB" ]; then
    echo "❌ SQLite database not found at $SQLITE_DB"
    exit 1
fi

echo "✅ Found SQLite database"

# Check if PostgreSQL is running
if ! docker-compose ps postgres | grep -q "Up"; then
    echo "❌ PostgreSQL container is not running. Please start it first:"
    echo "   docker-compose up -d postgres"
    exit 1
fi

echo "✅ PostgreSQL container is running"

# Load environment variables
if [ -f .env.production ]; then
    export $(cat .env.production | grep -v '^#' | xargs)
fi

# Check if DATABASE_URL is set for PostgreSQL
if [ -z "$DATABASE_URL" ] || ! echo "$DATABASE_URL" | grep -q "postgresql://"; then
    echo "❌ DATABASE_URL is not set to PostgreSQL"
    echo "   Please update .env.production with PostgreSQL DATABASE_URL"
    exit 1
fi

echo "✅ PostgreSQL DATABASE_URL is configured"

# Create backup directory
BACKUP_DIR="./backups"
mkdir -p "$BACKUP_DIR"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
BACKUP_FILE="$BACKUP_DIR/sqlite_backup_$TIMESTAMP.json"

echo "📦 Exporting data from SQLite..."
echo "   Backup will be saved to: $BACKUP_FILE"

# Export data from SQLite using Django's dumpdata
# First, temporarily switch to SQLite
docker-compose exec -T backend bash -c "
    export DATABASE_URL=sqlite:///db.sqlite3
    python manage.py dumpdata --natural-foreign --natural-primary --exclude auth.permission --exclude contenttypes > /tmp/sqlite_export.json 2>&1 || true
    cat /tmp/sqlite_export.json
" > "$BACKUP_FILE"

# Check if export was successful
if [ ! -s "$BACKUP_FILE" ] || grep -q "Error\|Traceback\|Exception" "$BACKUP_FILE"; then
    echo "⚠️  Warning: Export may have issues, but continuing..."
fi

echo "✅ Data exported to $BACKUP_FILE"
echo "   File size: $(du -h "$BACKUP_FILE" | cut -f1)"

# Wait for PostgreSQL to be ready
echo "⏳ Waiting for PostgreSQL to be ready..."
timeout=30
while [ $timeout -gt 0 ]; do
    if docker-compose exec -T postgres pg_isready -U ${POSTGRES_USER:-gnx} > /dev/null 2>&1; then
        echo "✅ PostgreSQL is ready"
        break
    fi
    echo "   Waiting for PostgreSQL... ($timeout seconds remaining)"
    sleep 2
    timeout=$((timeout - 2))
done

if [ $timeout -le 0 ]; then
    echo "❌ PostgreSQL is not ready. Please check the logs:"
    echo "   docker-compose logs postgres"
    exit 1
fi

# Create database if it doesn't exist
echo "📊 Ensuring PostgreSQL database exists..."
docker-compose exec -T postgres psql -U ${POSTGRES_USER:-gnx} -d postgres -c "SELECT 1 FROM pg_database WHERE datname='${POSTGRES_DB:-gnxdb}'" | grep -q 1 || \
docker-compose exec -T postgres psql -U ${POSTGRES_USER:-gnx} -d postgres -c "CREATE DATABASE ${POSTGRES_DB:-gnxdb};"

echo "✅ Database exists or created"

# Run migrations on PostgreSQL
echo "📦 Running migrations on PostgreSQL..."
docker-compose exec -T backend python manage.py migrate --noinput

echo "✅ Migrations completed"

# Import data into PostgreSQL
echo "📥 Importing data into PostgreSQL..."
if docker-compose exec -T backend bash -c "python manage.py loaddata /tmp/sqlite_export.json" < "$BACKUP_FILE" 2>&1 | tee /tmp/import_log.txt; then
    echo "✅ Data imported successfully"
else
    echo "⚠️  Warning: Some data may not have imported. Check the log above."
    echo "   You can retry the import manually:"
    echo "   docker-compose exec backend python manage.py loaddata /tmp/sqlite_export.json"
fi

# Verify data transfer
echo "🔍 Verifying data transfer..."
SQLITE_COUNT=$(docker-compose exec -T backend bash -c "export DATABASE_URL=sqlite:///db.sqlite3 && python manage.py shell -c \"from django.contrib.auth.models import User; print(User.objects.count())\"" 2>/dev/null | tail -1 || echo "0")
POSTGRES_COUNT=$(docker-compose exec -T backend python manage.py shell -c "from django.contrib.auth.models import User; print(User.objects.count())" 2>/dev/null | tail -1 || echo "0")

echo ""
echo "📊 Migration Summary:"
echo "   SQLite Users: $SQLITE_COUNT"
echo "   PostgreSQL Users: $POSTGRES_COUNT"
echo ""

# Create a flag file to indicate migration is complete
touch .migrated_to_postgres

echo "✅ Migration completed!"
echo ""
echo "📋 Next steps:"
echo "   1. Verify the data in PostgreSQL:"
echo "      docker-compose exec backend python manage.py shell"
echo ""
echo "   2. Test the application with PostgreSQL"
echo ""
echo "   3. Once verified, you can backup and remove SQLite:"
echo "      mv backEnd/db.sqlite3 backEnd/db.sqlite3.backup"
echo ""
echo "   Backup file saved at: $BACKUP_FILE"