#!/bin/bash
#
# Install and configure Redis server for WordPress on LLSMP/AlmaLinux
# - Installs redis via dnf
# - Configures Unix socket at /var/run/redis/redis.sock
# - Sets litespeed user as member of redis group for socket access
# - Enables and starts redis service
# - Configures LiteSpeed Cache Plugin Object Cache via WP-CLI
#

set -euo pipefail

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

info()      { printf "${BLUE}[INFO] %s${NC}\n" "$@"; }
success()   { printf "${GREEN}[SUCCESS] %s${NC}\n" "$@"; }
warning()   { printf "${YELLOW}[WARNING] %s${NC}\n" "$@"; }
error_exit(){ printf "${RED}[ERROR] %s${NC}\n" "$@" >&2; exit 1; }

REDIS_SOCKET="/var/run/redis/redis.sock"
REDIS_CONF="/etc/redis/redis.conf"
REDIS_CONF_ALT="/etc/redis.conf"
WP_ROOT="/var/www/webroot/ROOT"
WEB_USER="litespeed"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# ── 1. Detect active Redis conf path ────────────────────────────────────────
get_redis_conf() {
    if [[ -f "$REDIS_CONF" ]]; then
        echo "$REDIS_CONF"
    elif [[ -f "$REDIS_CONF_ALT" ]]; then
        echo "$REDIS_CONF_ALT"
    else
        echo ""
    fi
}

# ── 2. Install Redis if not present ─────────────────────────────────────────
install_redis() {
    if command -v redis-server >/dev/null 2>&1; then
        info "Redis server binary already present at $(which redis-server)"
        return 0
    fi

    info "Installing Redis via dnf..."
    dnf install -y redis || error_exit "Failed to install Redis. Check dnf connectivity."
    success "Redis installed successfully."
}

# ── 3. Configure Redis for Unix socket ──────────────────────────────────────
configure_redis() {
    local conf
    conf=$(get_redis_conf)

    if [[ -z "$conf" ]]; then
        error_exit "Redis config file not found at $REDIS_CONF or $REDIS_CONF_ALT"
    fi

    info "Configuring Redis at $conf..."

    # Backup original config (idempotent - only once)
    if [[ ! -f "${conf}.orig" ]]; then
        cp "$conf" "${conf}.orig"
        info "Original config backed up to ${conf}.orig"
    fi

    # Disable TCP listener (bind to 127.0.0.1 only, no external exposure)
    sed -i 's/^bind .*/bind 127.0.0.1/' "$conf"

    # Enable Unix socket
    if grep -q '^unixsocket ' "$conf"; then
        sed -i "s|^unixsocket .*|unixsocket $REDIS_SOCKET|" "$conf"
    else
        echo "unixsocket $REDIS_SOCKET" >> "$conf"
    fi

    # Set socket permissions so litespeed group can access it
    if grep -q '^unixsocketperm ' "$conf"; then
        sed -i 's/^unixsocketperm .*/unixsocketperm 775/' "$conf"
    else
        echo "unixsocketperm 775" >> "$conf"
    fi

    # Sensible memory limit (256MB default, adjustable)
    if ! grep -q '^maxmemory ' "$conf"; then
        echo "maxmemory 256mb" >> "$conf"
        echo "maxmemory-policy allkeys-lru" >> "$conf"
    fi

    # Ensure socket directory exists with correct ownership
    mkdir -p "$(dirname "$REDIS_SOCKET")"
    chown redis:redis "$(dirname "$REDIS_SOCKET")"

    success "Redis configuration applied."
}

# ── 4. Grant litespeed user access to redis socket ──────────────────────────
configure_socket_access() {
    info "Granting $WEB_USER user access to Redis socket group..."
    if id "$WEB_USER" >/dev/null 2>&1; then
        usermod -aG redis "$WEB_USER" || warning "Could not add $WEB_USER to redis group"
        success "$WEB_USER added to redis group."
    else
        warning "User $WEB_USER not found, skipping group membership."
    fi
}

# ── 5. Enable and start Redis service ───────────────────────────────────────
start_redis() {
    # Detect actual service name (redis, redis6, redis7, etc.)
    local svc
    svc=$(systemctl list-unit-files --type=service | grep -oP '[\w@-]*redis[\w@-]*\.service' | head -1 | sed 's/\.service//')

    if [[ -z "$svc" ]]; then
        error_exit "No Redis systemd service unit found after installation. Something went wrong."
    fi

    info "Enabling and starting $svc..."
    systemctl enable "$svc"
    systemctl restart "$svc"

    # Wait up to 10s for socket to appear
    local retries=10
    while [[ $retries -gt 0 ]]; do
        if [[ -S "$REDIS_SOCKET" ]]; then
            break
        fi
        sleep 1
        retries=$((retries - 1))
    done

    if [[ ! -S "$REDIS_SOCKET" ]]; then
        error_exit "Redis started but socket not found at $REDIS_SOCKET after 10 seconds. Check Redis logs: journalctl -u $svc"
    fi

    # Verify connectivity
    local ping_result
    ping_result=$(redis-cli -s "$REDIS_SOCKET" ping 2>/dev/null || echo "FAILED")
    if [[ "$ping_result" != "PONG" ]]; then
        error_exit "Redis socket exists but PING failed. Check Redis logs: journalctl -u $svc"
    fi

    success "Redis is running and responding on $REDIS_SOCKET"
}

# ── 6. Configure LiteSpeed Cache Plugin Object Cache ────────────────────────
configure_wp_object_cache() {
    local plugin_script="$SCRIPT_DIR/configure_litespeed_plugin_object_cache.sh"

    if [[ ! -f "$plugin_script" ]]; then
        warning "configure_litespeed_plugin_object_cache.sh not found at $plugin_script - skipping WP object cache config."
        return 0
    fi

    if [[ ! -f "$WP_ROOT/wp-config.php" ]]; then
        warning "WordPress not found at $WP_ROOT - skipping WP object cache config."
        return 0
    fi

    info "Configuring LiteSpeed Cache Plugin Object Cache with Redis socket..."
    if bash "$plugin_script" --enable --connection-type=socket --redis-socket="$REDIS_SOCKET" --wp-root="$WP_ROOT"; then
        success "WordPress LiteSpeed Cache Plugin Object Cache configured successfully."
    else
        warning "Failed to configure WordPress Object Cache. You can run it manually: bash $plugin_script --enable --wp-root=$WP_ROOT"
    fi
}

# ── Main ─────────────────────────────────────────────────────────────────────
info "======== Redis Install & Configure for WordPress (LLSMP) ========"

install_redis
configure_redis
configure_socket_access
start_redis
configure_wp_object_cache

success "======== Redis setup complete ========"
info "Socket:  $REDIS_SOCKET"
info "Config:  $(get_redis_conf)"
info "Test:    redis-cli -s $REDIS_SOCKET ping"