#!/usr/bin/env bash
set -euo pipefail

# EveryTab Postgres Setup — for dedicated i3 database instance
# Run on the i3.large EC2 instance (475GB local NVMe).
# Configures Postgres to use the NVMe for data storage.
# Optimized for write-heavy bulk loads — fsync disabled, large buffers.
# Data is ephemeral — back up with pg_dump before terminating the instance.

echo "=== EveryTab Postgres Setup (i3 NVMe) ==="

# --- Format and mount the NVMe drive ---
echo "--- Setting up NVMe storage ---"
NVME_DEV="/dev/nvme1n1"
NVME_MOUNT="/data"

if [ ! -d "$NVME_MOUNT" ]; then
    # Find the NVMe instance store (not the root EBS)
    # i3.large has one 475GB NVMe at /dev/nvme1n1 or similar
    if [ ! -b "$NVME_DEV" ]; then
        # Try finding it
        NVME_DEV=$(lsblk -dpno NAME,SIZE | grep -v "$(lsblk -dpno NAME /)" | head -1 | awk '{print $1}')
        if [ -z "$NVME_DEV" ]; then
            echo "ERROR: Could not find NVMe instance store device"
            echo "Run 'lsblk' and set NVME_DEV manually"
            exit 1
        fi
    fi
    echo "Using NVMe device: $NVME_DEV"
    sudo mkfs.xfs -f "$NVME_DEV"
    sudo mkdir -p "$NVME_MOUNT"
    sudo mount "$NVME_DEV" "$NVME_MOUNT"
    sudo chown ec2-user:ec2-user "$NVME_MOUNT"
    echo "Mounted $NVME_DEV at $NVME_MOUNT"
else
    echo "NVMe already mounted at $NVME_MOUNT"
fi

# --- Install Postgres ---
echo "--- Installing PostgreSQL 16 ---"
if ! command -v pg_isready &>/dev/null; then
    sudo dnf install -y postgresql16-server
fi

# --- Init database on NVMe ---
echo "--- Initializing database on NVMe ---"
PG_DATA="$NVME_MOUNT/pgdata"
if [ ! -d "$PG_DATA" ]; then
    sudo mkdir -p "$PG_DATA"
    sudo chown postgres:postgres "$PG_DATA"
    sudo -u postgres /usr/bin/initdb -D "$PG_DATA"
fi

# --- Configure for pipeline workload ---
echo "--- Configuring for bulk load performance ---"
PRIVATE_IP=$(hostname -I | awk '{print $1}')

sudo tee "$PG_DATA/postgresql.conf" > /dev/null <<EOF
# Connection — listen on private IP for compute instance
listen_addresses = 'localhost,$PRIVATE_IP'
port = 5432
max_connections = 100

# Memory — i3.large has 15.25GB RAM, Postgres gets most of it
shared_buffers = 8GB
work_mem = 512MB
maintenance_work_mem = 2GB
effective_cache_size = 12GB

# Write performance — data is reproducible, maximize speed over durability
fsync = off
synchronous_commit = off
full_page_writes = off

# WAL — minimal logging since no replication needed
wal_level = minimal
max_wal_senders = 0
max_wal_size = 8GB
checkpoint_timeout = 30min
checkpoint_completion_target = 0.9

# Autovacuum
autovacuum = on
autovacuum_naptime = 60s
EOF

# Allow connections from VPC (10.0.0.0/8 and 172.16.0.0/12 cover most VPC CIDRs)
sudo tee "$PG_DATA/pg_hba.conf" > /dev/null <<'EOF'
# Local connections
local   all   all                 trust
host    all   all   127.0.0.1/32  trust
host    all   all   ::1/128       trust
# VPC connections (from compute instance)
host    all   all   10.0.0.0/8    trust
host    all   all   172.16.0.0/12 trust
EOF

# --- Start with custom data directory ---
echo "--- Starting PostgreSQL ---"
sudo tee /etc/systemd/system/postgresql-everytab.service > /dev/null <<EOF
[Unit]
Description=PostgreSQL for EveryTab (NVMe)
After=network.target

[Service]
Type=forking
User=postgres
ExecStart=/usr/bin/pg_ctl start -D $PG_DATA -l $PG_DATA/pg.log
ExecStop=/usr/bin/pg_ctl stop -D $PG_DATA
ExecReload=/usr/bin/pg_ctl reload -D $PG_DATA

[Install]
WantedBy=multi-user.target
EOF

sudo systemctl daemon-reload
sudo systemctl enable postgresql-everytab
sudo systemctl restart postgresql-everytab

# --- Create database ---
echo "--- Creating everytab database ---"
sudo -u postgres psql -p 5432 -c "CREATE USER everytab;" 2>/dev/null || true
sudo -u postgres psql -p 5432 -c "CREATE DATABASE everytab OWNER everytab;" 2>/dev/null || true

# --- Apply schema ---
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
SCHEMA="$SCRIPT_DIR/../pipeline/01_cc_index/schema.sql"
if [ -f "$SCHEMA" ]; then
    echo "--- Applying schema ---"
    psql -U everytab -h localhost -d everytab -f "$SCHEMA"
else
    echo "Warning: schema.sql not found at $SCHEMA"
    echo "Copy it over and run: psql -U everytab -h localhost -d everytab -f schema.sql"
fi

# --- Validate ---
echo ""
echo "=== Validation ==="
pg_isready -h localhost
psql -U everytab -h localhost -d everytab -c "SELECT 'Postgres OK';" -t -A
echo "NVMe disk usage:"
df -h "$NVME_MOUNT"

echo ""
echo "=== Setup Complete ==="
echo ""
echo "Private IP: $PRIVATE_IP"
echo ""
echo "Connection string (from compute instance):"
echo "  export DATABASE_URL='postgres://everytab@${PRIVATE_IP}:5432/everytab'"
echo ""
echo "Connection string (local):"
echo "  export DATABASE_URL='postgres://everytab@localhost:5432/everytab'"
echo ""
echo "IMPORTANT: Ensure the compute instance's security group allows"
echo "outbound traffic to this instance on port 5432, and this instance's"
echo "security group allows inbound on 5432 from the compute instance."