運送・物流倉庫・3PL向け：
2026年SCS評価制度（★3）取得実践ガイド：WMS（倉庫管理）・EDI配車システムの停止防止と縮退運転BCP

#![forbid(unsafe_code)]

use std::collections::{BTreeMap, BTreeSet};

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct EdiShipmentOrder {
    pub shipper_id: u32,
    pub sequence_no: u64,
    pub ship_to_gln: u64,
    pub sku_code: u64,
    pub quantity: u32,
    pub historical_max_qty: u32,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct OfflinePickEvent {
    pub event_id: u128,
    pub terminal_id: u16,
    pub lamport_ts: u64,
    pub location_id: u32,
    pub sku_code: u64,
    pub picked_qty: i32,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum LogisticsBcpError {
    ReplaySequenceDetected { last_seq: u64, received_seq: u64 },
    UnapprovedShipToDestination { ship_to_gln: u64 },
    AnomalousQuantityRequiresHumanApproval { qty: u32, max_allowed: u32 },
    NegativeInventoryAfterReconcile { location_id: u32, sku_code: u64, resulting_qty: i64 },
}

/// Validates an incoming EDI shipment instruction against replay attacks,
/// unapproved Ship-To redirection scams, and abnormal volume spikes.
pub fn validate_edi_shipment_order(
    order: &EdiShipmentOrder,
    last_committed_seq: u64,
    approved_ship_to_glns: &BTreeSet<u64>,
) -> Result<(), LogisticsBcpError> {
    if order.sequence_no <= last_committed_seq {
        return Err(LogisticsBcpError::ReplaySequenceDetected {
            last_seq: last_committed_seq,
            received_seq: order.sequence_no,
        });
    }

    if !approved_ship_to_glns.contains(&order.ship_to_gln) {
        return Err(LogisticsBcpError::UnapprovedShipToDestination {
            ship_to_gln: order.ship_to_gln,
        });
    }

    if order.quantity > order.historical_max_qty {
        return Err(LogisticsBcpError::AnomalousQuantityRequiresHumanApproval {
            qty: order.quantity,
            max_allowed: order.historical_max_qty,
        });
    }

    Ok(())
}

/// Idempotently merges offline handheld barcode picking events recorded during
/// degraded-mode operation onto a restored ZFS snapshot inventory state.
pub fn reconcile_offline_pick_events(
    snapshot_inventory: &BTreeMap<(u32, u64), i64>,
    already_committed_events: &BTreeSet<u128>,
    offline_batch: &[OfflinePickEvent],
) -> Result<(BTreeMap<(u32, u64), i64>, usize), LogisticsBcpError> {
    let mut updated = snapshot_inventory.clone();
    let mut seen_ids = already_committed_events.clone();
    let mut applied_count = 0usize;

    let mut sorted_events = offline_batch.to_vec();
    sorted_events.sort_by_key(|e| (e.lamport_ts, e.terminal_id, e.event_id));

    for ev in &sorted_events {
        if !seen_ids.insert(ev.event_id) {
            continue; — Idempotent skip: event already committed before or during sync
        }
        let key = (ev.location_id, ev.sku_code);
        let current = updated.entry(key).or_insert(0);
        *current -= i64::from(ev.picked_qty);
        if *current < 0 {
            return Err(LogisticsBcpError::NegativeInventoryAfterReconcile {
                location_id: ev.location_id,
                sku_code: ev.sku_code,
                resulting_qty: *current,
            });
        }
        applied_count += 1;
    }

    Ok((updated, applied_count))
}