#!/bin/bash
# Vault Snapshot Backup to Cloudflare R2
# Usage: ./vault-backup-r2.sh [snapshot-name]

set -euo pipefail

# ============================================
# Configuration
# ============================================
VAULT_ADDR="${VAULT_ADDR:-https://vault.anvil.it.com}"
VAULT_TOKEN="${VAULT_TOKEN:?VAULT_TOKEN is required}"

# R2 Configuration
R2_ACCOUNT_ID="${R2_ACCOUNT_ID:?R2_ACCOUNT_ID is required}"
R2_ACCESS_KEY="${R2_ACCESS_KEY:?R2_ACCESS_KEY is required}"
R2_SECRET_KEY="${R2_SECRET_KEY:?R2_SECRET_KEY is required}"
R2_BUCKET="${R2_BUCKET:-vault-backup}"
R2_ENDPOINT="https://${R2_ACCOUNT_ID}.r2.cloudflarestorage.com"

# Backup settings
BACKUP_DIR="${BACKUP_DIR:-/tmp/vault-backups}"
RETENTION_DAYS="${RETENTION_DAYS:-30}"
TIMESTAMP=$(date +%Y%m%d-%H%M%S)
SNAPSHOT_NAME="${1:-vault-snapshot-${TIMESTAMP}}"

# ============================================
# Functions
# ============================================

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

error() {
    log "ERROR: $*" >&2
    exit 1
}

check_dependencies() {
    for cmd in curl aws jq; do
        if ! command -v "$cmd" &>/dev/null; then
            error "$cmd is required but not installed"
        fi
    done
}

create_snapshot() {
    log "Creating Vault snapshot..."

    mkdir -p "$BACKUP_DIR"
    local snapshot_file="${BACKUP_DIR}/${SNAPSHOT_NAME}.snap"

    # Vault Raft snapshot (requires Raft storage backend)
    curl -s -X POST \
        -H "X-Vault-Token: ${VAULT_TOKEN}" \
        "${VAULT_ADDR}/v1/sys/storage/raft/snapshot" \
        -o "$snapshot_file" \
        --fail || {
            # Fallback: Export secrets as JSON (for non-Raft backends)
            log "Raft snapshot failed, trying secrets export..."
            export_secrets "$snapshot_file"
        }

    echo "$snapshot_file"
}

export_secrets() {
    local output_file="$1"
    local secrets_file="${output_file%.snap}.json"

    log "Exporting secrets to JSON..."

    # Get list of secret paths (requires list permission)
    local paths=$(curl -s -X LIST \
        -H "X-Vault-Token: ${VAULT_TOKEN}" \
        "${VAULT_ADDR}/v1/secret/metadata" | jq -r '.data.keys[]?' 2>/dev/null || echo "")

    if [[ -z "$paths" ]]; then
        log "No secrets found or no list permission"
        echo '{"secrets": [], "timestamp": "'$(date -Iseconds)'", "note": "empty or no permission"}' > "$secrets_file"
    else
        echo '{"secrets": [' > "$secrets_file"
        local first=true

        for path in $paths; do
            local secret=$(curl -s \
                -H "X-Vault-Token: ${VAULT_TOKEN}" \
                "${VAULT_ADDR}/v1/secret/data/${path}" | jq '.data' 2>/dev/null)

            if [[ -n "$secret" && "$secret" != "null" ]]; then
                if [[ "$first" == "true" ]]; then
                    first=false
                else
                    echo "," >> "$secrets_file"
                fi
                echo "{\"path\": \"${path}\", \"data\": ${secret}}" >> "$secrets_file"
            fi
        done

        echo '], "timestamp": "'$(date -Iseconds)'"}' >> "$secrets_file"
    fi

    # Compress and encrypt (optional)
    gzip -c "$secrets_file" > "$output_file"
    rm -f "$secrets_file"
}

upload_to_r2() {
    local file="$1"
    local filename=$(basename "$file")

    log "Uploading to R2: ${R2_BUCKET}/${filename}"

    # Configure AWS CLI for R2
    export AWS_ACCESS_KEY_ID="$R2_ACCESS_KEY"
    export AWS_SECRET_ACCESS_KEY="$R2_SECRET_KEY"

    aws s3 cp "$file" "s3://${R2_BUCKET}/${filename}" \
        --endpoint-url "$R2_ENDPOINT" \
        --quiet

    log "Upload complete: s3://${R2_BUCKET}/${filename}"
}

cleanup_old_backups() {
    log "Cleaning up backups older than ${RETENTION_DAYS} days..."

    export AWS_ACCESS_KEY_ID="$R2_ACCESS_KEY"
    export AWS_SECRET_ACCESS_KEY="$R2_SECRET_KEY"

    local cutoff_date=$(date -v-${RETENTION_DAYS}d +%Y-%m-%d 2>/dev/null || date -d "${RETENTION_DAYS} days ago" +%Y-%m-%d)

    aws s3 ls "s3://${R2_BUCKET}/" --endpoint-url "$R2_ENDPOINT" 2>/dev/null | \
    while read -r line; do
        local file_date=$(echo "$line" | awk '{print $1}')
        local file_name=$(echo "$line" | awk '{print $4}')

        if [[ "$file_date" < "$cutoff_date" && -n "$file_name" ]]; then
            log "Deleting old backup: $file_name"
            aws s3 rm "s3://${R2_BUCKET}/${file_name}" --endpoint-url "$R2_ENDPOINT" --quiet
        fi
    done
}

cleanup_local() {
    log "Cleaning up local backup files..."
    find "$BACKUP_DIR" -name "vault-snapshot-*.snap" -mtime +1 -delete 2>/dev/null || true
    find "$BACKUP_DIR" -name "vault-snapshot-*.gz" -mtime +1 -delete 2>/dev/null || true
}

# ============================================
# Main
# ============================================

main() {
    log "=== Vault Backup to R2 Started ==="
    log "Vault: $VAULT_ADDR"
    log "R2 Bucket: $R2_BUCKET"

    check_dependencies

    local snapshot_file
    snapshot_file=$(create_snapshot)

    if [[ -f "$snapshot_file" ]]; then
        upload_to_r2 "$snapshot_file"
        cleanup_old_backups
        cleanup_local
        log "=== Backup Complete ==="
    else
        error "Snapshot file not created"
    fi
}

main "$@"