#!/usr/bin/env bash
# gniza4linux/lib/backup.sh — Backup orchestration per target

[[ -n "${_GNIZA4LINUX_BACKUP_LOADED:-}" ]] && return 0
_GNIZA4LINUX_BACKUP_LOADED=1

# Backup a single target to a remote.
# Usage: backup_target <target_name> [remote_name]
backup_target() {
    local target_name="$1"
    local remote_name="${2:-}"

    # 1. Load and validate target
    load_target "$target_name" || {
        log_error "Failed to load target: $target_name"
        return 1
    }

    if [[ "${TARGET_ENABLED:-yes}" != "yes" ]]; then
        log_info "Target '$target_name' is disabled, skipping"
        return 0
    fi

    # 2. Determine which remote to use
    if [[ -z "$remote_name" ]]; then
        if [[ -n "${TARGET_REMOTE:-}" ]]; then
            remote_name="$TARGET_REMOTE"
        else
            remote_name=$(list_remotes | head -1)
        fi
    fi

    if [[ -z "$remote_name" ]]; then
        log_error "No remote specified and none configured"
        return 1
    fi

    # 3. Save/load remote context
    _save_remote_globals
    load_remote "$remote_name" || {
        log_error "Failed to load remote: $remote_name"
        _restore_remote_globals
        return 1
    }

    local rc=0
    _backup_target_impl "$target_name" "$remote_name" || rc=$?

    # 15. Restore remote globals
    _restore_remote_globals
    return "$rc"
}

# Internal implementation after remote context is loaded.
_backup_target_impl() {
    local target_name="$1"
    local remote_name="$2"

    # 4. Test remote connectivity
    case "${REMOTE_TYPE:-ssh}" in
        ssh)
            test_ssh_connection || {
                log_error "Cannot connect to remote '$remote_name'"
                return 1
            }
            ;;
        local)
            if [[ ! -d "$REMOTE_BASE" ]]; then
                log_error "Remote base directory does not exist: $REMOTE_BASE"
                return 1
            fi
            ;;
        s3|gdrive)
            test_rclone_connection || {
                log_error "Cannot connect to remote '$remote_name' (${REMOTE_TYPE})"
                return 1
            }
            ;;
    esac

    local start_time; start_time=$(date +%s)

    # 5. Get timestamp
    local ts; ts=$(timestamp)

    # 6. Get previous snapshot for --link-dest
    local prev; prev=$(get_latest_snapshot "$target_name") || prev=""
    if [[ -n "$prev" ]]; then
        log_debug "Previous snapshot for $target_name: $prev"
    fi

    # 7. Clean partial snapshots
    clean_partial_snapshots "$target_name"

    # 8. Run pre-hook
    if [[ -n "${TARGET_PRE_HOOK:-}" ]]; then
        log_info "Running pre-hook for $target_name..."
        if ! bash -c "$TARGET_PRE_HOOK"; then
            log_error "Pre-hook failed for $target_name"
            return 1
        fi
    fi

    # 8.5. Dump MySQL databases (if enabled)
    local mysql_dump_dir=""
    if [[ "${TARGET_MYSQL_ENABLED:-no}" == "yes" ]]; then
        log_info "Dumping MySQL databases for $target_name..."
        if mysql_dump_databases; then
            mysql_dump_dir="${MYSQL_DUMP_DIR:-}"
        else
            log_error "MySQL dump failed for $target_name"
            mysql_cleanup_dump
            return 1
        fi
    fi

    # 9. Transfer each folder
    local folder
    local transfer_failed=false
    while IFS= read -r folder; do
        [[ -z "$folder" ]] && continue
        if ! transfer_folder "$target_name" "$folder" "$ts" "$prev"; then
            log_error "Transfer failed for folder: $folder"
            transfer_failed=true
        fi
    done < <(get_target_folders)

    # 9.5. Transfer MySQL dumps
    if [[ -n "$mysql_dump_dir" && -d "$mysql_dump_dir/_mysql" ]]; then
        log_info "Transferring MySQL dumps for $target_name..."
        if ! transfer_folder "$target_name" "$mysql_dump_dir/_mysql" "$ts" "$prev"; then
            log_error "Transfer failed for MySQL dumps"
            transfer_failed=true
        fi
    fi

    # Cleanup MySQL temp dir
    mysql_cleanup_dump

    if [[ "$transfer_failed" == "true" ]]; then
        log_error "One or more folder transfers failed for $target_name"
        return 1
    fi

    # 10. Generate meta.json
    local end_time; end_time=$(date +%s)
    local duration=$(( end_time - start_time ))
    local hostname; hostname=$(hostname -f)
    local snap_dir; snap_dir=$(get_snapshot_dir "$target_name")
    local total_size=0

    local meta_json
    meta_json=$(cat <<METAEOF
{
  "target": "$target_name",
  "hostname": "$hostname",
  "timestamp": "$ts",
  "duration": $duration,
  "folders": "$(echo "$TARGET_FOLDERS" | sed 's/"/\\"/g')",
  "mysql_dumps": $([ "${TARGET_MYSQL_ENABLED:-no}" = "yes" ] && echo "true" || echo "false"),
  "total_size": $total_size,
  "mode": "${BACKUP_MODE:-$DEFAULT_BACKUP_MODE}",
  "pinned": false
}
METAEOF
)

    if _is_rclone_mode; then
        local meta_subpath="targets/${target_name}/snapshots/${ts}/meta.json"
        rclone_rcat "$meta_subpath" "$meta_json" || log_warn "Failed to write meta.json"
    elif [[ "${REMOTE_TYPE:-ssh}" == "local" ]]; then
        echo "$meta_json" > "$snap_dir/${ts}.partial/meta.json" || log_warn "Failed to write meta.json"
    else
        echo "$meta_json" | remote_exec "cat > '$snap_dir/${ts}.partial/meta.json'" || log_warn "Failed to write meta.json"
    fi

    # 11. Generate manifest.txt
    if _is_rclone_mode; then
        local manifest; manifest=$(rclone_list_files "targets/${target_name}/snapshots/${ts}" 2>/dev/null) || manifest=""
        if [[ -n "$manifest" ]]; then
            rclone_rcat "targets/${target_name}/snapshots/${ts}/manifest.txt" "$manifest" || log_warn "Failed to write manifest.txt"
        fi
    elif [[ "${REMOTE_TYPE:-ssh}" == "local" ]]; then
        find "$snap_dir/${ts}.partial" -type f 2>/dev/null > "$snap_dir/${ts}.partial/manifest.txt" || log_warn "Failed to write manifest.txt"
    else
        remote_exec "find '$snap_dir/${ts}.partial' -type f > '$snap_dir/${ts}.partial/manifest.txt'" 2>/dev/null || log_warn "Failed to write manifest.txt"
    fi

    # 12. Finalize snapshot
    if ! finalize_snapshot "$target_name" "$ts"; then
        log_error "Failed to finalize snapshot for $target_name"
        return 1
    fi

    # Calculate total_size after finalization for accurate reporting
    if _is_rclone_mode; then
        local size_json; size_json=$(rclone_size "targets/${target_name}/snapshots/${ts}" 2>/dev/null) || true
        if [[ -n "$size_json" ]]; then
            total_size=$(echo "$size_json" | grep -oP '"bytes":\s*\K[0-9]+' || echo 0)
        fi
    elif [[ "${REMOTE_TYPE:-ssh}" == "local" ]]; then
        total_size=$(du -sb "$snap_dir/$ts" 2>/dev/null | cut -f1) || total_size=0
    else
        total_size=$(remote_exec "du -sb '$snap_dir/$ts' 2>/dev/null | cut -f1" 2>/dev/null) || total_size=0
    fi

    log_info "Backup completed for $target_name: $ts ($(human_size "${total_size:-0}") in $(human_duration "$duration"))"

    # 13. Run post-hook
    if [[ -n "${TARGET_POST_HOOK:-}" ]]; then
        log_info "Running post-hook for $target_name..."
        bash -c "$TARGET_POST_HOOK" || log_warn "Post-hook failed for $target_name"
    fi

    # 14. Enforce retention
    enforce_retention "$target_name"

    return 0
}

# Backup all enabled targets.
# Usage: backup_all_targets [remote_flag]
backup_all_targets() {
    local remote_flag="${1:-}"

    local targets; targets=$(list_targets)
    if [[ -z "$targets" ]]; then
        log_error "No targets configured"
        return 1
    fi

    # Resolve remotes
    local remotes=""
    remotes=$(get_target_remotes "$remote_flag") || {
        log_error "Invalid remote specification"
        return 1
    }

    local start_time; start_time=$(date +%s)
    local total=0 succeeded=0 failed=0
    local failed_targets=""

    while IFS= read -r target_name; do
        [[ -z "$target_name" ]] && continue

        load_target "$target_name" || { log_warn "Cannot load target: $target_name"; continue; }
        if [[ "${TARGET_ENABLED:-yes}" != "yes" ]]; then
            log_debug "Target '$target_name' is disabled, skipping"
            continue
        fi

        ((total++)) || true
        log_info "=== Backing up target: $target_name ($total) ==="

        local target_failed=false
        while IFS= read -r rname; do
            [[ -z "$rname" ]] && continue
            log_info "--- Transferring $target_name to remote '$rname' ---"
            if ! backup_target "$target_name" "$rname"; then
                log_error "Backup to remote '$rname' failed for $target_name"
                failed_targets+="  - $target_name ($rname: failed)"$'\n'
                target_failed=true
            fi
        done <<< "$remotes"

        if [[ "$target_failed" == "true" ]]; then
            ((failed++)) || true
        else
            ((succeeded++)) || true
            log_info "Backup completed for $target_name (all remotes)"
        fi
    done <<< "$targets"

    local end_time; end_time=$(date +%s)
    local duration=$(( end_time - start_time ))

    # Print summary
    echo ""
    echo "============================================"
    echo "Backup Summary"
    echo "============================================"
    echo "Timestamp:   $(timestamp)"
    echo "Duration:    $(human_duration $duration)"
    echo "Remotes:     $(echo "$remotes" | tr '\n' ' ')"
    echo "Total:       $total"
    echo "Succeeded:   ${C_GREEN}${succeeded}${C_RESET}"
    if (( failed > 0 )); then
        echo "Failed:      ${C_RED}${failed}${C_RESET}"
        echo ""
        echo "Failed targets:"
        echo "$failed_targets"
    else
        echo "Failed:      0"
    fi
    echo "============================================"

    # Send notification
    send_backup_report "$total" "$succeeded" "$failed" "$duration" "$failed_targets"

    if (( failed > 0 && succeeded > 0 )); then
        return "$EXIT_PARTIAL"
    elif (( failed > 0 )); then
        return 1
    fi
    return 0
}