//! 背包领域错误。
//!
//! 错误保持可测试的业务语义，例如数量不足、槽位冲突和物品不存在。

use std::{error::Error, fmt};

#[derive(Clone, Debug, PartialEq, Eq)]
pub enum InventoryMutationFieldError {
    MissingMutationId,
    MissingRuntimeSessionId,
    MissingActorUserId,
    MissingSlotId,
    MissingItemId,
    MissingCategory,
    MissingName,
    InvalidQuantity,
    MissingStackKey,
    NonStackableItemMustStaySingleQuantity,
    EquipmentItemCannotStack,
    SlotScopeMismatch,
    ItemNotFound,
    ItemNotInBackpack,
    ItemNotEquipped,
    InsufficientQuantity,
    ItemNotEquippable,
}

impl fmt::Display for InventoryMutationFieldError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::MissingMutationId => f.write_str("inventory_mutation.mutation_id 不能为空"),
            Self::MissingRuntimeSessionId => {
                f.write_str("inventory_mutation.runtime_session_id 不能为空")
            }
            Self::MissingActorUserId => f.write_str("inventory_mutation.actor_user_id 不能为空"),
            Self::MissingSlotId => f.write_str("inventory_slot.slot_id 不能为空"),
            Self::MissingItemId => f.write_str("inventory_item.item_id 不能为空"),
            Self::MissingCategory => f.write_str("inventory_item.category 不能为空"),
            Self::MissingName => f.write_str("inventory_item.name 不能为空"),
            Self::InvalidQuantity => f.write_str("inventory_item.quantity 必须大于 0"),
            Self::MissingStackKey => f.write_str("可堆叠物品必须提供 stack_key"),
            Self::NonStackableItemMustStaySingleQuantity => {
                f.write_str("不可堆叠物品必须固定为单槽位单数量")
            }
            Self::EquipmentItemCannotStack => f.write_str("可装备物品不能标记为 stackable"),
            Self::SlotScopeMismatch => {
                f.write_str("当前 inventory_slot 不属于本次 mutation 作用域")
            }
            Self::ItemNotFound => f.write_str("目标 inventory_slot 不存在"),
            Self::ItemNotInBackpack => f.write_str("目标物品当前不在背包中"),
            Self::ItemNotEquipped => f.write_str("目标物品当前不在装备位上"),
            Self::InsufficientQuantity => f.write_str("当前背包数量不足，无法完成扣减"),
            Self::ItemNotEquippable => f.write_str("目标物品当前不可装备"),
        }
    }
}

impl Error for InventoryMutationFieldError {}