p52: 玩家交易通道——买/卖经 Sim.quotePrice→Occupation.biasedQuote，背包侧车/钱财增减 + v3 round-trip + HUD 短反馈(design §2.4-2)

1 files changed, 230 insertions, 0 deletions

diff --git a/src/LivingVillage.Desktop/PlayerTrade.fs b/src/LivingVillage.Desktop/PlayerTrade.fs
new file mode 100644
index 0000000..e1ea53e
--- /dev/null
+++ b/src/LivingVillage.Desktop/PlayerTrade.fs
@@ -0,0 +1,230 @@
+namespace LivingVillage.Desktop
+
+open LivingVillage.Kernel
+open LivingVillage.Kernel.Sim
+
+/// P52 职业切片二：把 P51 落盘的职业背包侧车变成玩家在世界里可用的物品
+/// （docs/design-professions.md §2.4-2）。
+///
+/// 口径：
+/// - 定价仍走既有 `Sim.quotePrice`，再经 `Occupation.biasedQuote`；无职业恒等 1.0。
+/// - 钱写 `world.Avatar.Mind.Needs.Money`，物品写 `Occupation.State.Backpack`（侧车）。
+/// - 交易像 `Sim.trade` 一样追加 `TradeEvent` + `TradeAnnal` 并写双方记忆，
+///   但**不动** `Sim.step` / 地图 / seed，也不给 Avatar 加 Inventory 字段。
+///
+/// 玩家不是 `world.Npcs` 成员（`playerId = NpcId -1`），而 `Sim.quotePrice` 只认
+/// `Npcs`。这里把玩家侧（Avatar 需求/人格 + 背包）镜像成一个临时 `Npc` 追加进
+/// 「报价世界副本」再调用 `Sim.quotePrice`；副本只用于报价，不写回真实世界。
+module PlayerTrade =
+
+    type Outcome =
+        { World: World
+          Occupation: Occupation.State option
+          Succeeded: bool
+          /// 成交时的职业偏置后单位价（失败为 None）。
+          UnitPrice: float32 option
+          /// 面向 HUD 的短中文反馈。
+          Message: string }
+
+    let private itemName (item: ItemKind) : string =
+        match item with
+        | Food -> "食物"
+        | Fish -> "鱼"
+        | Spice -> "香料"
+        | Scroll -> "卷轴"
+
+    let private quantityOf (item: ItemKind) (inventory: Map<ItemKind, int>) : int =
+        inventory |> Map.tryFind item |> Option.defaultValue 0
+
+    let private changeItem (item: ItemKind) (delta: int) (inventory: Map<ItemKind, int>) : Map<ItemKind, int> =
+        let next = quantityOf item inventory + delta
+        if next <= 0 then Map.remove item inventory else Map.add item next inventory
+
+    let private backpackMap (backpack: (ItemKind * int) list) : Map<ItemKind, int> =
+        backpack
+        |> List.fold (fun acc (item, quantity) -> Map.add item (quantityOf item acc + quantity) acc) Map.empty
+
+    /// 背包增减，保持声明顺序；归零移除，新物品追加到尾部。
+    let private changeBackpack (item: ItemKind) (delta: int) (backpack: (ItemKind * int) list) : (ItemKind * int) list =
+        let mutable found = false
+        let updated =
+            backpack
+            |> List.choose (fun (kind, quantity) ->
+                if kind = item then
+                    found <- true
+                    let next = quantity + delta
+                    if next <= 0 then None else Some(kind, next)
+                else
+                    Some(kind, quantity))
+        if not found && delta > 0 then updated @ [ item, delta ] else updated
+
+    let private quoteWorld (world: World) (state: Occupation.State option) : World =
+        let backpack = state |> Option.map (fun s -> s.Backpack) |> Option.defaultValue []
+        let playerNpc =
+            { Id = playerId
+              Pos = world.Avatar.Pos
+              Inventory = backpackMap backpack
+              Mind = world.Avatar.Mind }
+        { world with Npcs = Array.append world.Npcs [| playerNpc |] }
+
+    let private requestFor (playerIsBuyer: bool) (counterparty: NpcId) (item: ItemKind) (quantity: int) : TradeRequest =
+        if playerIsBuyer then
+            { Buyer = playerId; Seller = counterparty; Item = item; Quantity = quantity }
+        else
+            { Buyer = counterparty; Seller = playerId; Item = item; Quantity = quantity }
+
+    /// 未偏置的 `Sim.quotePrice` 结果（玩家侧镜像为临时参与者）。
+    let quoteBase
+        (state: Occupation.State option)
+        (playerIsBuyer: bool)
+        (counterparty: NpcId)
+        (item: ItemKind)
+        (quantity: int)
+        (world: World)
+        : float32 option =
+        Sim.quotePrice (requestFor playerIsBuyer counterparty item quantity) (quoteWorld world state)
+
+    /// 最终成交单价 = `Sim.quotePrice` → `Occupation.biasedQuote`。
+    let quote
+        (state: Occupation.State option)
+        (playerIsBuyer: bool)
+        (counterparty: NpcId)
+        (item: ItemKind)
+        (quantity: int)
+        (world: World)
+        : float32 option =
+        let kind = state |> Option.map (fun s -> s.Profile.Kind)
+        quoteBase state playerIsBuyer counterparty item quantity world
+        |> Occupation.biasedQuote kind playerIsBuyer
+
+    let private replaceNpc (npc: Npc) (world: World) : World =
+        { world with Npcs = world.Npcs |> Array.map (fun current -> if current.Id = npc.Id then npc else current) }
+
+    let private recordTrade
+        (buyer: NpcId)
+        (seller: NpcId)
+        (item: ItemKind)
+        (quantity: int)
+        (unitPrice: float32)
+        (world: World)
+        : World =
+        let event =
+            { Tick = world.Tick
+              Kind = TradeEvent(buyer, seller, item, quantity, unitPrice) }
+        let entry =
+            { Tick = world.Tick
+              Kind = TradeAnnal event
+              Summary =
+                sprintf "trade tick=%d buyer=%A seller=%A item=%A quantity=%d price=%.2f"
+                    world.Tick buyer seller item quantity unitPrice }
+        Sim.appendAnnal entry { world with Events = world.Events @ [ event ] }
+
+    let private failure (state: Occupation.State option) (world: World) (message: string) : Outcome =
+        { World = world; Occupation = state; Succeeded = false; UnitPrice = None; Message = message }
+
+    /// 玩家向 `counterparty` 买入 `quantity` 件 `item`。
+    let buy
+        (state: Occupation.State option)
+        (counterparty: NpcId)
+        (item: ItemKind)
+        (quantity: int)
+        (world: World)
+        : Outcome =
+        match state with
+        | None -> failure state world "未选择职业"
+        | Some occupation ->
+            match world.Npcs |> Array.tryFind (fun npc -> npc.Id = counterparty) with
+            | None -> failure state world "找不到对方"
+            | Some seller when quantity <= 0 -> failure state world "数量必须大于零"
+            | Some seller ->
+                if quantityOf item seller.Inventory < quantity then
+                    failure state world "库存不足"
+                else
+                    match quote (Some occupation) true counterparty item quantity world with
+                    | None -> failure state world "无法报价"
+                    | Some unitPrice ->
+                        let total = unitPrice * float32 quantity
+                        if world.Avatar.Mind.Needs.Money < total then
+                            failure state world "资金不足"
+                        else
+                            let avatarMind =
+                                { world.Avatar.Mind with
+                                    Needs = { world.Avatar.Mind.Needs with Money = world.Avatar.Mind.Needs.Money - total }
+                                    Memory = recordMemory world.Tick (Bought(counterparty, item, quantity, unitPrice)) world.Avatar.Mind.Memory }
+                            let updatedSeller =
+                                { seller with
+                                    Inventory = changeItem item -quantity seller.Inventory
+                                    Mind =
+                                        { seller.Mind with
+                                            Needs = { seller.Mind.Needs with Money = seller.Mind.Needs.Money + total }
+                                            Memory = recordMemory world.Tick (Sold(playerId, item, quantity, unitPrice)) seller.Mind.Memory } }
+                            let nextWorld =
+                                world
+                                |> (fun w -> { w with Avatar = { w.Avatar with Mind = avatarMind } })
+                                |> replaceNpc updatedSeller
+                                |> recordTrade playerId counterparty item quantity unitPrice
+                            { World = nextWorld
+                              Occupation = Some { occupation with Backpack = changeBackpack item quantity occupation.Backpack }
+                              Succeeded = true
+                              UnitPrice = Some unitPrice
+                              Message = sprintf "买入%s ×%d，单价 %.2f" (itemName item) quantity unitPrice }
+
+    /// 玩家向 `counterparty` 卖出 `quantity` 件 `item`（须在背包内）。
+    let sell
+        (state: Occupation.State option)
+        (counterparty: NpcId)
+        (item: ItemKind)
+        (quantity: int)
+        (world: World)
+        : Outcome =
+        match state with
+        | None -> failure state world "未选择职业"
+        | Some occupation ->
+            match world.Npcs |> Array.tryFind (fun npc -> npc.Id = counterparty) with
+            | None -> failure state world "找不到对方"
+            | Some buyer when quantity <= 0 -> failure state world "数量必须大于零"
+            | Some buyer ->
+                if Occupation.backpackQuantity item occupation < quantity then
+                    failure state world "背包不足"
+                else
+                    match quote (Some occupation) false counterparty item quantity world with
+                    | None -> failure state world "无法报价"
+                    | Some unitPrice ->
+                        let total = unitPrice * float32 quantity
+                        if buyer.Mind.Needs.Money < total then
+                            failure state world "对方资金不足"
+                        else
+                            let avatarMind =
+                                { world.Avatar.Mind with
+                                    Needs = { world.Avatar.Mind.Needs with Money = world.Avatar.Mind.Needs.Money + total }
+                                    Memory = recordMemory world.Tick (Sold(counterparty, item, quantity, unitPrice)) world.Avatar.Mind.Memory }
+                            let updatedBuyer =
+                                { buyer with
+                                    Inventory = changeItem item quantity buyer.Inventory
+                                    Mind =
+                                        { buyer.Mind with
+                                            Needs = { buyer.Mind.Needs with Money = buyer.Mind.Needs.Money - total }
+                                            Memory = recordMemory world.Tick (Bought(playerId, item, quantity, unitPrice)) buyer.Mind.Memory } }
+                            let nextWorld =
+                                world
+                                |> (fun w -> { w with Avatar = { w.Avatar with Mind = avatarMind } })
+                                |> replaceNpc updatedBuyer
+                                |> recordTrade counterparty playerId item quantity unitPrice
+                            { World = nextWorld
+                              Occupation = Some { occupation with Backpack = changeBackpack item -quantity occupation.Backpack }
+                              Succeeded = true
+                              UnitPrice = Some unitPrice
+                              Message = sprintf "卖出%s ×%d，单价 %.2f" (itemName item) quantity unitPrice }
+
+    /// HUD 入口：向 `counterparty` 买 1 件食物。
+    let buyFood (state: Occupation.State option) (counterparty: NpcId) (world: World) : Outcome =
+        buy state counterparty Food 1 world
+
+    /// HUD 入口：卖出背包里第一件有货的物品 1 件；背包为空则失败。
+    let sellFirst (state: Occupation.State option) (counterparty: NpcId) (world: World) : Outcome =
+        match state with
+        | None -> failure state world "未选择职业"
+        | Some occupation ->
+            match occupation.Backpack |> List.tryFind (fun (_, quantity) -> quantity > 0) with
+            | None -> failure state world "背包里没有可卖物品"
+            | Some(item, quantity) -> sell state counterparty item (min 1 quantity) world