#!/usr/bin/env bash
# ==============================================================================
#  backup_db.sh — Admin Edu-Space (UniCABA)
#  Generador de backups de PostgreSQL y actualización de classrooms_db.sql
#  Uso:  bash backup_db.sh
# ==============================================================================

set -euo pipefail

RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'
CYAN='\033[0;36m'; BOLD='\033[1m'; RESET='\033[0m'

ok()   { echo -e "${GREEN}  ✔ $*${RESET}"; }
info() { echo -e "${CYAN}  ▸ $*${RESET}"; }
warn() { echo -e "${YELLOW}  ⚠ $*${RESET}"; }
err()  { echo -e "${RED}  ✘ $*${RESET}" >&2; exit 1; }
hdr()  { echo -e "\n${BOLD}${CYAN}══ $* ══${RESET}\n"; }

APP_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
BACKUP_DIR="${APP_DIR}/backups"
TIMESTAMP="$(date +'%Y%m%d_%H%M%S')"
BACKUP_FILE="${BACKUP_DIR}/classrooms_db_${TIMESTAMP}.sql"
ROOT_BACKUP="${APP_DIR}/classrooms_db.sql"
APP_ENV="${APP_DIR}/.env"

mkdir -p "$BACKUP_DIR"

hdr "Iniciando Backup de la Base de Datos"

# 1. Obtener parámetros de conexión
DB_NAME="classrooms_db"
DB_USER="eduspace_user"
DB_HOST="localhost"
DB_PORT="5432"
DB_PASSWORD=""

if [[ -f "$APP_ENV" ]]; then
    set -a
    # shellcheck disable=SC1090
    source <(grep -v '^#' "$APP_ENV" | grep '=')
    set +a
    if [[ -n "${DATABASE_URL:-}" ]]; then
        # Extraer credenciales desde DATABASE_URL si existe
        # Formato: postgresql://usuario:pass@host:port/dbname
        DB_USER=$(echo "$DATABASE_URL" | sed -E 's|.*://([^:]+):?([^@]*)@.*|\1|')
        DB_PASSWORD=$(echo "$DATABASE_URL" | sed -E 's|.*://[^:]+:([^@]*)@.*|\1|')
        DB_HOST=$(echo "$DATABASE_URL" | sed -E 's|.*@([^:/]+):?.*|\1|')
        DB_PORT=$(echo "$DATABASE_URL" | sed -E 's|.*:([0-9]+)/.*|\1|')
        DB_NAME=$(echo "$DATABASE_URL" | sed -E 's|.*/([^?]+).*|\1|')
    fi
fi

DB_USER="${DB_USER:-postgres}"
DB_NAME="${DB_NAME:-classrooms_db}"
DB_HOST="${DB_HOST:-localhost}"
DB_PORT="${DB_PORT:-5432}"

info "Base de datos: ${DB_NAME}"
info "Usuario:       ${DB_USER}"
info "Host:          ${DB_HOST}:${DB_PORT}"

# 2. Ejecutar pg_dump
info "Generando volcado SQL..."

export PGPASSWORD="${DB_PASSWORD:-}"

if command -v pg_dump >/dev/null 2>&1; then
    # Intentar como usuario configurado
    if pg_dump -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
        --no-owner --no-privileges --clean --if-exists > "$BACKUP_FILE" 2>/dev/null; then
        ok "Volcado generado con éxito usando pg_dump"
    elif [[ $EUID -eq 0 ]] || sudo -n true 2>/dev/null; then
        info "Reintentando volcado como superusuario postgres..."
        sudo -u postgres pg_dump -d "$DB_NAME" --no-owner --no-privileges > "$BACKUP_FILE"
        ok "Volcado generado como usuario postgres"
    else
        err "No se pudo realizar el backup. Verifica tus permisos y credenciales."
    fi
else
    err "No se encontró la herramienta 'pg_dump'. Instala postgresql-client."
fi

# 3. Limpiar comandos de versiones específicas (ej: \restrict de PG 18) para máxima compatibilidad
sed -i '/^\\restrict/d' "$BACKUP_FILE" 2>/dev/null || true

# 4. Actualizar copia en raíz para despliegues automáticos
cp "$BACKUP_FILE" "$ROOT_BACKUP"

BACKUP_SIZE=$(du -h "$BACKUP_FILE" | awk '{print $1}')

hdr "Resumen del Backup"
ok "Archivo histórico: ${BACKUP_FILE} (${BACKUP_SIZE})"
ok "Copia para deploy: ${ROOT_BACKUP} (${BACKUP_SIZE})"
info "Para restaurar en otro servidor:"
echo -e "    ${CYAN}sudo -u postgres psql -d ${DB_NAME} < ${ROOT_BACKUP}${RESET}"
echo ""