#!/usr/bin/env bash
# scripts/backup.sh — Automated PostgreSQL backup for Orion and Gitea
#
# Usage:
#   bash scripts/backup.sh              # Local backup only
#   bash scripts/backup.sh --upload     # Local backup + sync to Cloudflare R2
#
# Cron / systemd timer: runs daily at 03:00
# On Sundays: copies daily backup to weekly/
# Retention: 7 daily, 4 weekly

set -euo pipefail

# =============================================================================
# Configuration
# =============================================================================
BACKUP_ROOT="${HOME}/backups"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
DAY_OF_WEEK=$(date +%u)  # 1=Monday, 7=Sunday

# Orion DB settings (from docker-compose.yml)
ORION_CONTAINER="orion-db-1"
ORION_DB="orion_db"
ORION_USER="orion_user"

# Gitea DB settings (from ~/gitea/docker-compose.yml)
GITEA_CONTAINER="gitea-db"
GITEA_DB="gitea"
GITEA_USER="gitea"

# R2 settings (loaded from .env if available)
ORION_APP_DIR="${HOME}/apps/orion"
if [ -f "${ORION_APP_DIR}/.env" ]; then
    R2_ACCOUNT_ID=$(grep -s '^R2_ACCOUNT_ID=' "${ORION_APP_DIR}/.env" | cut -d= -f2- || true)
    R2_BACKUP_BUCKET=$(grep -s '^R2_BACKUP_BUCKET=' "${ORION_APP_DIR}/.env" | cut -d= -f2- || true)
fi
R2_BACKUP_BUCKET="${R2_BACKUP_BUCKET:-orion-backups}"
R2_ENDPOINT="https://${R2_ACCOUNT_ID}.r2.cloudflarestorage.com"

# Retention
DAILY_KEEP=7
WEEKLY_KEEP=4

# =============================================================================
# Functions
# =============================================================================
log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*"
}

backup_database() {
    local container="$1"
    local db_name="$2"
    local db_user="$3"
    local target_dir="$4"
    local filename="$5"

    mkdir -p "${target_dir}"

    log "Backing up ${db_name} from ${container}..."
    if docker exec "${container}" pg_dump -U "${db_user}" "${db_name}" | gzip > "${target_dir}/${filename}"; then
        local size
        size=$(du -h "${target_dir}/${filename}" | cut -f1)
        log "  OK: ${filename} (${size})"
    else
        log "  FAILED: ${db_name} backup"
        return 1
    fi
}

rotate_backups() {
    local dir="$1"
    local keep_days="$2"

    if [ -d "${dir}" ]; then
        local count
        count=$(find "${dir}" -name "*.sql.gz" -mtime +"${keep_days}" 2>/dev/null | wc -l)
        if [ "${count}" -gt 0 ]; then
            find "${dir}" -name "*.sql.gz" -mtime +"${keep_days}" -delete
            log "  Rotated: removed ${count} old backups from ${dir}"
        fi
    fi
}

upload_to_r2() {
    if [ -z "${R2_ACCOUNT_ID:-}" ]; then
        log "ERROR: R2_ACCOUNT_ID not set. Cannot upload."
        return 1
    fi

    log "Syncing backups to R2 bucket: ${R2_BACKUP_BUCKET}..."
    aws s3 sync "${BACKUP_ROOT}/" "s3://${R2_BACKUP_BUCKET}/" \
        --endpoint-url "${R2_ENDPOINT}" \
        --profile r2 \
        --delete \
        --exclude "*.tmp"
    log "  OK: R2 sync complete"
}

# =============================================================================
# Main
# =============================================================================
UPLOAD=false
if [ "${1:-}" = "--upload" ]; then
    UPLOAD=true
fi

log "=== Orion Backup Started ==="

# Ensure backup directories exist
mkdir -p "${BACKUP_ROOT}/orion/"{daily,weekly}
mkdir -p "${BACKUP_ROOT}/gitea/"{daily,weekly}

# --- Daily backups ---
ERRORS=0

backup_database "${ORION_CONTAINER}" "${ORION_DB}" "${ORION_USER}" \
    "${BACKUP_ROOT}/orion/daily" "orion_${TIMESTAMP}.sql.gz" || ERRORS=$((ERRORS + 1))

backup_database "${GITEA_CONTAINER}" "${GITEA_DB}" "${GITEA_USER}" \
    "${BACKUP_ROOT}/gitea/daily" "gitea_${TIMESTAMP}.sql.gz" || ERRORS=$((ERRORS + 1))

# --- Weekly copies (Sunday) ---
if [ "${DAY_OF_WEEK}" -eq 7 ]; then
    log "Sunday: copying to weekly/"
    cp -f "${BACKUP_ROOT}/orion/daily/orion_${TIMESTAMP}.sql.gz" \
          "${BACKUP_ROOT}/orion/weekly/" 2>/dev/null || true
    cp -f "${BACKUP_ROOT}/gitea/daily/gitea_${TIMESTAMP}.sql.gz" \
          "${BACKUP_ROOT}/gitea/weekly/" 2>/dev/null || true
fi

# --- Rotation ---
log "Rotating old backups..."
rotate_backups "${BACKUP_ROOT}/orion/daily" "${DAILY_KEEP}"
rotate_backups "${BACKUP_ROOT}/gitea/daily" "${DAILY_KEEP}"
rotate_backups "${BACKUP_ROOT}/orion/weekly" $((WEEKLY_KEEP * 7))
rotate_backups "${BACKUP_ROOT}/gitea/weekly" $((WEEKLY_KEEP * 7))

# --- Optional R2 upload ---
if [ "${UPLOAD}" = true ]; then
    upload_to_r2 || ERRORS=$((ERRORS + 1))
fi

# --- Summary ---
if [ "${ERRORS}" -eq 0 ]; then
    log "=== Backup completed successfully ==="
else
    log "=== Backup completed with ${ERRORS} error(s) ==="
    exit 1
fi