defmodule BearCli.Vault do
  @moduledoc """
  `bear vault` 指令群（issue #17、docs/commands.md §3.11）。

  對接 alterminal/bear 的 `/api/v1/vault` JSON API（PAT Bearer，
  alterminal/bear#41）。端到端加密全在本模組與 `BearCli.Vault.Crypto`／
  `BearCli.Vault.BIP39` 完成，格式與 Web Vault（P2）完全一致：

    - 加密字串 `"2.<iv>.<ct>.<mac>"`（AES-256-CBC＋HMAC-SHA-256、
      encrypt-then-MAC）
    - 主金鑰 PBKDF2-SHA512（迭代數以 `GET /api/v1/vault/config` 公告與
      profile 記錄為準，不寫死；salt＝帳號 email 小寫）
    - 助記詞 BIP39（12 字、128-bit 熵、英文詞表）

  **K_user 僅存記憶體**（不寫憑證檔／任何磁碟位置）：`vault unlock` 解開
  K_user 後以 session 環境變數 `BEAR_VAULT_SESSION`（base64）交給後續
  指令（同 Bitwarden CLI 的 `BW_SESSION` 慣例；環境變數只存在於 shell
  記憶體，不落盤）。`vault lock` 指示丟棄（unset）。

  - 主密碼／助記詞以互動提示讀取（不回顧、不進 shell history、不接受
    命令列明文參數）；非 TTY 環境 → 退出碼 2。
  - 助記詞只在 Web Vault 設定時顯示一次；CLI 不提供重新顯示，僅提供
    `vault rescue`（助記詞救援重設主密碼）。
  - 退出碼：0 成功；1 一般錯誤（404／422、主密碼／助記詞錯誤）；2 用法
    錯誤（含非 TTY）；3 未登入或 401；6 網路／伺服器錯誤；8 權限不足。
  """

  alias BearCli.{Api, Config, Credentials}
  alias BearCli.Vault.{BIP39, Crypto}

  @session_env "BEAR_VAULT_SESSION"

  @verbs ~w(status unlock lock list get create edit delete restore purge folders sync password rescue)
  @folder_verbs ~w(list create rename delete)
  @cipher_types ~w(login secure_note card identity)

  @folder_switches [folder: :string]
  @create_switches [type: :string, folder: :string, email: :string]

  # -- 解析（由 BearCli.CLI 轉入）--

  @doc """
  解析 `vault` 子指令樹，回 `{:ok, {BearCli.Vault, verb}, opts}`、
  `{:ok, {:vault_folders, verb}, opts}` 或 `{:error, message, 2}`。
  """
  def parse(["vault" | args], global) do
    global_switches = [
      issuer: :string,
      config: :string,
      json: :boolean,
      verbose: :boolean,
      help: :boolean,
      version: :boolean,
      email: :string
    ]

    case args do
      ["folders", verb | rest] when verb in @folder_verbs ->
        case OptionParser.parse(rest, strict: global_switches) do
          {opts, positionals, []} ->
            validate_folders(verb, positionals, merge(global, opts))

          {_opts, _extra, [{opt, _} | _]} ->
            {:error, "無法解析選項：#{opt}", 2}
        end

      ["password", "change" | rest] ->
        case OptionParser.parse(rest, strict: global_switches) do
          {opts, [], []} ->
            {:ok, {__MODULE__, :password_change}, merge(global, opts)}

          {_opts, extra, []} ->
            {:error, "vault password change 不接受參數：#{Enum.join(extra, " ")}", 2}

          {_opts, _extra, [{opt, _} | _]} ->
            {:error, "無法解析選項：#{opt}", 2}
        end

      ["--help"] ->
        {:help, :vault}

      ["help"] ->
        {:help, :vault}

      [verb | rest] when verb in @verbs ->
        switches = verb_switches(verb)

        case OptionParser.parse(rest, strict: global_switches ++ switches) do
          {opts, positionals, []} ->
            validate(verb, positionals, merge(global, opts))

          {_opts, _extra, [{opt, _} | _]} ->
            {:error, "無法解析選項：#{opt}", 2}
        end

      [] ->
        {:error, "vault 缺少子指令（可用：#{Enum.join(@verbs, " ")}）", 2}

      [unknown | _] ->
        {:error, "未知的 vault 子指令：#{unknown}（可用：#{Enum.join(@verbs, " ")}）", 2}
    end
  end

  defp verb_switches("list"), do: @folder_switches
  defp verb_switches("create"), do: @create_switches
  defp verb_switches(_), do: []

  defp merge(global, opts), do: Map.merge(Map.new(global), Map.new(opts))

  # -- 各動詞的位置參數驗證（用法錯誤 → 2）--

  defp validate("status", [], opts), do: {:ok, {__MODULE__, :status}, opts}
  defp validate("status", extra, _), do: extra_error("vault status", extra)

  defp validate("unlock", [], opts), do: {:ok, {__MODULE__, :unlock}, opts}
  defp validate("unlock", extra, _), do: extra_error("vault unlock", extra)

  defp validate("lock", [], opts), do: {:ok, {__MODULE__, :lock}, opts}
  defp validate("lock", extra, _), do: extra_error("vault lock", extra)

  defp validate("list", [], opts), do: {:ok, {__MODULE__, :list}, opts}
  defp validate("list", extra, _), do: extra_error("vault list", extra)

  defp validate("get", [uuid], opts),
    do: {:ok, {__MODULE__, :get}, Map.put(opts, :uuid_arg, uuid)}

  defp validate("get", [], _), do: {:error, "vault get 缺少 <uuid>", 2}
  defp validate("get", extra, _), do: single_error("vault get", extra)

  defp validate("create", [], opts) do
    type = opts[:type]

    cond do
      blank?(type) ->
        {:error, "vault create 缺少 --type #{Enum.join(@cipher_types, "|")}", 2}

      type not in @cipher_types ->
        {:error, "--type 不接受的值：#{type}（可用：#{Enum.join(@cipher_types, "、")}）", 2}

      true ->
        {:ok, {__MODULE__, :create}, opts}
    end
  end

  defp validate("create", extra, _), do: extra_error("vault create", extra)

  defp validate("edit", [uuid], opts),
    do: {:ok, {__MODULE__, :edit}, Map.put(opts, :uuid_arg, uuid)}

  defp validate("edit", [], _), do: {:error, "vault edit 缺少 <uuid>", 2}
  defp validate("edit", extra, _), do: single_error("vault edit", extra)

  defp validate("delete", [uuid], opts),
    do: {:ok, {__MODULE__, :delete}, Map.put(opts, :uuid_arg, uuid)}

  defp validate("delete", [], _), do: {:error, "vault delete 缺少 <uuid>", 2}
  defp validate("delete", extra, _), do: single_error("vault delete", extra)

  defp validate("restore", [uuid], opts),
    do: {:ok, {__MODULE__, :restore}, Map.put(opts, :uuid_arg, uuid)}

  defp validate("restore", [], _), do: {:error, "vault restore 缺少 <uuid>", 2}
  defp validate("restore", extra, _), do: single_error("vault restore", extra)

  defp validate("purge", [uuid], opts),
    do: {:ok, {__MODULE__, :purge}, Map.put(opts, :uuid_arg, uuid)}

  defp validate("purge", [], _), do: {:error, "vault purge 缺少 <uuid>", 2}
  defp validate("purge", extra, _), do: single_error("vault purge", extra)

  defp validate("sync", [], opts), do: {:ok, {__MODULE__, :sync}, opts}
  defp validate("sync", extra, _), do: extra_error("vault sync", extra)

  defp validate("rescue", [], opts), do: {:ok, {__MODULE__, :rescue}, opts}
  defp validate("rescue", extra, _), do: extra_error("vault rescue", extra)

  defp validate_folders("list", [], opts), do: {:ok, {__MODULE__, :folders_list}, opts}
  defp validate_folders("list", extra, _), do: extra_error("vault folders list", extra)

  defp validate_folders("create", [], opts), do: {:ok, {__MODULE__, :folders_create}, opts}
  defp validate_folders("create", extra, _), do: extra_error("vault folders create", extra)

  defp validate_folders("rename", [uuid], opts),
    do: {:ok, {__MODULE__, :folders_rename}, Map.put(opts, :uuid_arg, uuid)}

  defp validate_folders("rename", [], _), do: {:error, "vault folders rename 缺少 <uuid>", 2}
  defp validate_folders("rename", extra, _), do: single_error("vault folders rename", extra)

  defp validate_folders("delete", [uuid], opts),
    do: {:ok, {__MODULE__, :folders_delete}, Map.put(opts, :uuid_arg, uuid)}

  defp validate_folders("delete", [], _), do: {:error, "vault folders delete 缺少 <uuid>", 2}
  defp validate_folders("delete", extra, _), do: single_error("vault folders delete", extra)

  defp extra_error(cmd, extra),
    do: {:error, "#{cmd} 不接受位置參數：#{Enum.join(extra, " ")}", 2}

  defp single_error(cmd, extra),
    do: {:error, "#{cmd} 只接受一個 <uuid>（多餘：#{Enum.join(Enum.drop(extra, 1), " ")}）", 2}

  # -- 執行入口 --

  @doc """
  執行 vault 指令，回傳退出碼。`opts[:vault_api]` 可注入假 API 模組、
  `opts[:io]` 注入互動輸入（`prompt_secret/1` 與 `prompt/2`）、
  `opts[:tty?]` 覆寫 TTY 判定、`opts[:session]` 注入 session 金鑰供測試。
  """
  def run(:help, _opts) do
    IO.puts("""
    bear vault — 密碼管理指令群（docs/commands.md §3.11）

    用法：bear vault <子指令> [選項]

    子指令：
      status                       初始化狀態、KDF 參數、解鎖狀態
      unlock                       主密碼解鎖 → 匯出 BEAR_VAULT_SESSION（K_user 僅記憶體）
      lock                         丟棄 session（unset BEAR_VAULT_SESSION）
      list [--folder UUID]         列出項目（解鎖後顯示明文名稱）
      get <uuid>                   顯示單一項目（解鎖後解密欄位）
      create --type login|secure_note|card|identity [--folder UUID]
      edit <uuid>                  互動編輯（Enter 保留現值）
      delete <uuid>                丟入回收桶
      restore <uuid>               從回收桶還原
      purge <uuid>                 永久刪除（需確認）
      folders list|create|rename <uuid>|delete <uuid>
      sync                         完整同步（伺服器為準）
      password change              變更 vault 主密碼
      rescue                       助記詞救援（重設主密碼）
    """)

    0
  end

  def run(verb, opts) do
    api = opts[:vault_api] || Api

    with {:ok, ctx} <- context(opts, api) do
      execute(verb, ctx, opts, api)
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  # -- 各指令實作 --

  defp execute(:status, ctx, opts, api) do
    # 先看 profile（404＝未初始化）；config 取不到時以 profile 的 KDF 為準。
    with {:ok, profile} <- fetch_profile(ctx, opts, api),
         {:ok, config} <- fetch_config(ctx, opts, api) do
      kdf = profile["kdf"] || %{}
      iterations = kdf["iterations"]

      if opts[:json] do
        IO.puts(
          Jason.encode!(%{
            ok: true,
            initialized: true,
            enabled: profile["enabled"],
            kdf: kdf,
            iterations: iterations,
            encryption_types: config["encryption_types"],
            security_stamp: profile["security_stamp"],
            last_synced_at: profile["last_synced_at"],
            unlocked: session_key(opts) != nil
          })
        )
      else
        IO.puts("Vault 狀態：已初始化#{if profile["enabled"] == false, do: "（已停用）", else: ""}")
        IO.puts("KDF：#{kdf["hash"] || "?"}／#{iterations || "?"} 迭代（salt＝帳號 email 小寫）")
        IO.puts("上次同步：#{profile["last_synced_at"] || "(從未)"}")

        IO.puts(
          "解鎖狀態：#{if session_key(opts), do: "已解鎖（本 shell）", else: "未解鎖（bear vault unlock）"}"
        )
      end

      0
    else
      {:error, :not_initialized} ->
        if opts[:json] do
          IO.puts(Jason.encode!(%{ok: true, initialized: false, unlocked: false}))
        else
          IO.puts("Vault 狀態：尚未初始化（請至 Web Vault /vault 頁面設定主密碼與助記詞）")
        end

        0

      {:error, message, code} ->
        fail(opts, message, code)
    end
  end

  defp execute(:unlock, ctx, opts, api) do
    with {:ok, profile} <- fetch_profile(ctx, opts, api),
         {:ok, k_user} <- unlock_with_password(ctx, profile, opts, api) do
      session = Base.encode64(k_user)

      if opts[:json] do
        IO.puts(Jason.encode!(%{ok: true, session: session, env: @session_env}))
      else
        IO.puts("已解鎖（K_user 僅存本 shell 記憶體；以下指令匯入 session）：")
        IO.puts("  export #{@session_env}=#{session}")
        IO.puts("或一次性使用：#{@session_env}=<…> bear vault list")
        IO.puts("鎖定：bear vault lock（unset #{@session_env}）")
      end

      0
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:lock, _ctx, opts, _api) do
    cond do
      opts[:session] || System.get_env(@session_env) ->
        IO.puts("請執行：unset #{@session_env}")
        IO.puts("（K_user 只存在 shell 環境變數，unset 即丟棄）")
        0

      true ->
        IO.puts("目前 shell 未持有 session（#{@session_env} 未設定）。")
        0
    end
  end

  defp execute(:list, ctx, opts, api) do
    with {:ok, body} <- wrap_api(api.vault_ciphers_list(ctx.issuer, ctx.token), ctx, opts),
         {:ok, folders_body} <- wrap_api(api.vault_folders_list(ctx.issuer, ctx.token), ctx, opts) do
      ciphers = body["data"] || []
      folders = folders_body["data"] || []
      k_user = session_key(opts)

      folder_names =
        if k_user do
          Map.new(folders, fn f ->
            {f["folder_uuid"], decrypt_to(f["name"], k_user, "(無法解密)")}
          end)
        else
          %{}
        end

      ciphers
      |> Enum.filter(fn c ->
        case opts[:folder] do
          nil -> true
          folder_uuid -> (c["data"] || %{})["folder_uuid"] == folder_uuid
        end
      end)
      |> Enum.map(fn c -> cipher_row(c, k_user, folder_names) end)
      |> render_rows(["UUID", "NAME", "TYPE", "FOLDER", "UPDATED", "STATE"])

      if opts[:json] do
        IO.puts(
          Jason.encode!(%{
            ok: true,
            decrypted: k_user != nil,
            ciphers: Enum.map(ciphers, &cipher_json(&1, k_user, folder_names))
          })
        )
      end

      if ciphers == [] and not json?(opts) do
        IO.puts("(無資料)")
      end

      if k_user == nil and ciphers != [] and not json?(opts) do
        IO.puts("(名稱未解密；先 bear vault unlock 匯入 session)")
      end

      0
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:get, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    with {:ok, body} <- wrap_api(api.vault_ciphers_get(ctx.issuer, ctx.token, uuid), ctx, opts) do
      cipher = body["data"] || %{}
      k_user = session_key(opts)

      if opts[:json] do
        IO.puts(
          Jason.encode!(%{
            ok: true,
            decrypted: k_user != nil,
            cipher: cipher_json(cipher, k_key_or_map(cipher, k_user))
          })
        )
      else
        print_cipher(cipher, k_key_or_map(cipher, k_user))
        if k_user == nil, do: IO.puts("(欄位未解密；先 bear vault unlock 匯入 session)")
      end

      0
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:create, ctx, opts, api) do
    with {:ok, k_user} <- require_session(opts),
         {:ok, attrs} <- prompt_cipher_fields(opts, opts[:type]) do
      data =
        case opts[:folder] do
          nil -> %{}
          folder_uuid -> %{"folder_uuid" => folder_uuid}
        end

      attrs =
        Map.merge(attrs, %{
          "cipher_uuid" => new_uuid(),
          "cipher_type" => opts[:type],
          "data" => data,
          "favorite" => false,
          "reprompt" => 0
        })
        |> encrypt_attrs(k_user)

      case api.vault_ciphers_upsert(ctx.issuer, ctx.token, attrs) do
        {:ok, body} ->
          cipher = body["data"] || %{}

          if opts[:json] do
            IO.puts(Jason.encode!(%{ok: true, cipher: cipher}))
          else
            IO.puts("已建立：#{cipher["cipher_uuid"]}（#{opts[:type]}）")
          end

          0

        {:error, _kind, _detail} = error ->
          fail_api(opts, ctx, error)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:edit, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    with {:ok, k_user} <- require_session(opts),
         {:ok, body} <- wrap_api(api.vault_ciphers_get(ctx.issuer, ctx.token, uuid), ctx, opts),
         {:ok, attrs} <- prompt_edit_fields(opts, body["data"] || %{}, k_user) do
      case api.vault_ciphers_update(ctx.issuer, ctx.token, uuid, encrypt_attrs(attrs, k_user)) do
        {:ok, _body} ->
          if opts[:json] do
            IO.puts(Jason.encode!(%{ok: true, updated: uuid}))
          else
            IO.puts("已更新：#{uuid}")
          end

          0

        {:error, _kind, _detail} = error ->
          fail_api(opts, ctx, error)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:delete, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    case api.vault_ciphers_delete(ctx.issuer, ctx.token, uuid) do
      {:ok, _body} ->
        if opts[:json] do
          IO.puts(Jason.encode!(%{ok: true, trashed: uuid}))
        else
          IO.puts("已丟入回收桶：#{uuid}（還原：bear vault restore #{uuid}；永久刪除：bear vault purge #{uuid}）")
        end

        0

      {:error, _kind, _detail} = error ->
        fail_api(opts, ctx, error)
    end
  end

  defp execute(:restore, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    case api.vault_ciphers_restore(ctx.issuer, ctx.token, uuid) do
      {:ok, _body} ->
        if opts[:json] do
          IO.puts(Jason.encode!(%{ok: true, restored: uuid}))
        else
          IO.puts("已從回收桶還原：#{uuid}")
        end

        0

      {:error, _kind, _detail} = error ->
        fail_api(opts, ctx, error)
    end
  end

  defp execute(:purge, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    with :ok <- confirm_purge(opts, uuid) do
      case api.vault_ciphers_purge(ctx.issuer, ctx.token, uuid) do
        {:ok, _body} ->
          if opts[:json] do
            IO.puts(Jason.encode!(%{ok: true, purged: uuid}))
          else
            IO.puts("已永久刪除：#{uuid}")
          end

          0

        {:error, _kind, _detail} = error ->
          fail_api(opts, ctx, error)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:folders_list, ctx, opts, api) do
    with {:ok, body} <- wrap_api(api.vault_folders_list(ctx.issuer, ctx.token), ctx, opts) do
      folders = body["data"] || []
      k_user = session_key(opts)

      rows =
        Enum.map(folders, fn f ->
          name =
            if k_user,
              do: decrypt_to(f["name"], k_key(f["name"], k_user), "(無法解密)"),
              else: "(未解密)"

          [f["folder_uuid"], name, f["revision_date"] || ""]
        end)

      render_rows(rows, ["UUID", "NAME", "REVISED"])

      if opts[:json] do
        IO.puts(
          Jason.encode!(%{
            ok: true,
            decrypted: k_key_any(folders, k_user) != nil,
            folders:
              Enum.map(folders, fn f ->
                %{
                  "uuid" => f["folder_uuid"],
                  "name" => if(k_user, do: decrypt_to(f["name"], k_user, nil), else: nil)
                }
              end)
          })
        )
      end

      if folders == [] and not opts[:json], do: IO.puts("(無資料)")

      if k_user == nil and folders != [] and not opts[:json],
        do: IO.puts("(名稱未解密；先 bear vault unlock)")

      0
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:folders_create, ctx, opts, api) do
    with {:ok, k_user} <- require_session(opts),
         {:ok, name} <- prompt(opts, "資料夾名稱"),
         :ok <- require_nonempty(name) do
      attrs = %{"folder_uuid" => new_uuid(), "name" => Crypto.encrypt(name, k_user)}

      case api.vault_folders_upsert(ctx.issuer, ctx.token, attrs) do
        {:ok, body} ->
          folder = body["data"] || %{}

          if opts[:json] do
            IO.puts(
              Jason.encode!(%{
                ok: true,
                folder: %{"uuid" => folder["folder_uuid"], "name" => name}
              })
            )
          else
            IO.puts("已建立資料夾：#{folder["folder_uuid"]}")
          end

          0

        {:error, _kind, _detail} = error ->
          fail_api(opts, ctx, error)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:folders_rename, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    with {:ok, k_user} <- require_session(opts),
         {:ok, name} <- prompt(opts, "新的資料夾名稱"),
         :ok <- require_nonempty(name) do
      case api.vault_folders_rename(ctx.issuer, ctx.token, uuid, %{
             "name" => Crypto.encrypt(name, k_user)
           }) do
        {:ok, _body} ->
          if opts[:json] do
            IO.puts(Jason.encode!(%{ok: true, renamed: uuid}))
          else
            IO.puts("已重新命名：#{uuid}")
          end

          0

        {:error, _kind, _detail} = error ->
          fail_api(opts, ctx, error)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:folders_delete, ctx, opts, api) do
    uuid = opts[:uuid_arg]

    case api.vault_folders_delete(ctx.issuer, ctx.token, uuid) do
      {:ok, _body} ->
        if opts[:json] do
          IO.puts(Jason.encode!(%{ok: true, deleted: uuid}))
        else
          IO.puts("已刪除資料夾：#{uuid}（所屬項目不受影響，僅失去分類）")
        end

        0

      {:error, _kind, _detail} = error ->
        fail_api(opts, ctx, error)
    end
  end

  defp execute(:sync, ctx, opts, api) do
    with {:ok, body} <- wrap_api(api.vault_sync(ctx.issuer, ctx.token), ctx, opts) do
      data = body["data"] || %{}
      profile = data["profile"] || %{}
      folders = data["folders"] || []
      ciphers = data["data"] |> List.wrap() |> Enum.map(&(Map.get(&1, "data") || &1))
      cipher_list = data["ciphers"] || []

      if opts[:json] do
        IO.puts(Jason.encode!(%{ok: true, sync: data}))
      else
        IO.puts("同步完成（伺服器為準）：")
        IO.puts("  security_stamp：#{profile["security_stamp"] || "(未知)"}")
        IO.puts("  資料夾：#{length(folders)} 個")
        IO.puts("  項目：#{length(cipher_list)} 個（含回收桶）")
        IO.puts("  last_synced_at：#{profile["last_synced_at"] || "(首次)"}")
      end

      _ = ciphers
      0
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:password_change, ctx, opts, api) do
    with {:ok, profile} <- fetch_profile(ctx, opts, api),
         {:ok, k_user} <- unlock_with_password(ctx, profile, opts, api),
         {:ok, new_password} <- read_new_password(opts),
         true <- byte_size(new_password) >= 8 || {:error, "新主密碼至少需要 8 個字元", 2} do
      iterations = iterations_for(profile, ctx, opts, api)

      case iterations do
        {:ok, iterations} ->
          new_master = Crypto.derive_master_key(new_password, ctx.email, iterations)
          wrapped = Crypto.wrap_user_key(k_user, new_master)

          case api.vault_profile_put(ctx.issuer, ctx.token, %{"wrapped_user_password" => wrapped}) do
            {:ok, _body} ->
              if opts[:json] do
                IO.puts(Jason.encode!(%{ok: true}))
              else
                IO.puts("主密碼已更新；既有資料無需重新加密（K_user 未變）。")
                IO.puts("提醒：新的 session 匯入請重新 bear vault unlock。")
              end

              0

            {:error, _kind, _detail} = error ->
              fail_api(opts, ctx, error)
          end

        {:error, message, code} ->
          fail(opts, message, code)
      end
    else
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp execute(:rescue, ctx, opts, api) do
    with {:ok, profile} <- fetch_profile(ctx, opts, api),
         {:ok, mnemonic} <- prompt_secret(opts, "助記詞（12 字，空格分隔）"),
         true <- BIP39.valid?(mnemonic) || {:error, "助記詞無效（字數／詞表／校驗和檢查未過）", 1},
         {:ok, new_password} <- read_new_password(opts),
         true <- byte_size(new_password) >= 8 || {:error, "新主密碼至少需要 8 個字元", 2},
         {:ok, iterations} <- iterations_for(profile, ctx, opts, api),
         wrapped_mnemonic when is_binary(wrapped_mnemonic) <-
           profile["wrapped_user_mnemonic"] || {:error, "此 vault 未綁定助記詞（無法救援）", 1},
         seed = BIP39.mnemonic_to_seed(mnemonic),
         rescue_key = BIP39.rescue_key_from_seed(seed, ctx.email, iterations),
         {:ok, k_user} <- Crypto.unwrap_user_key(wrapped_mnemonic, rescue_key) do
      new_master = Crypto.derive_master_key(new_password, ctx.email, iterations)
      wrapped = Crypto.wrap_user_key(k_user, new_master)

      case api.vault_profile_put(ctx.issuer, ctx.token, %{"wrapped_user_password" => wrapped}) do
        {:ok, _body} ->
          if opts[:json] do
            IO.puts(Jason.encode!(%{ok: true}))
          else
            IO.puts("已透過助記詞重設主密碼；既有資料無需重新加密。")
          end

          0

        {:error, _kind, _detail} = error ->
          fail_api(opts, ctx, error)
      end
    else
      {:error, :invalid} ->
        fail(opts, "助記詞不正確（解不開 wrapped_user_mnemonic）", 1)

      {:error, message, code} ->
        fail(opts, message, code)
    end
  end

  # -- 背景（token／issuer／email）與金鑰 --

  defp context(opts, api) do
    token_source =
      cond do
        token = Config.env_token() -> {:env, token}
        true -> :file
      end

    case token_source do
      {:env, token} ->
        with {:ok, email} <- resolve_email(opts, api, token, nil) do
          {:ok, %{token: token, issuer: resolve_issuer(opts, nil), email: email}}
        end

      :file ->
        case Credentials.load() do
          {:ok, creds} ->
            token = creds["access_token"]

            if blank?(token) do
              {:error, "憑證檔缺少 access_token，請重新 bear login", 7}
            else
              with {:ok, email} <- resolve_email(opts, api, token, creds["email"]) do
                {:ok,
                 %{token: token, issuer: resolve_issuer(opts, creds["issuer"]), email: email}}
              end
            end

          :error ->
            {:error, "未登入（請先執行 bear login）", 3}
        end
    end
  end

  # salt＝帳號 email 小寫（與 Web Vault 一致）；來源優先序：
  # --email > 憑證檔 > 伺服器 profile。
  defp resolve_email(opts, _api, _token, creds_email) do
    email = opts[:email] || creds_email

    cond do
      is_binary(email) and email != "" -> {:ok, String.trim(email)}
      true -> {:error, "無法得知帳號 email（KDF salt 需要）；請以 --email EMAIL 提供", 2}
    end
  end

  defp resolve_issuer(opts, stored_issuer) do
    opts[:issuer] || stored_issuer || Config.resolve_issuer(nil, opts[:config])
  end

  defp fetch_config(ctx, _opts, api) do
    case api.vault_config(ctx.issuer, ctx.token) do
      {:ok, body} -> {:ok, body["data"] || %{}}
      {:error, _kind, _detail} = error -> api_error(ctx, error)
    end
  end

  # 404 → 未初始化（不以錯誤處理）
  defp fetch_profile(ctx, _opts, api) do
    case api.vault_profile_get(ctx.issuer, ctx.token) do
      {:ok, body} -> {:ok, body["data"] || %{}}
      {:error, :not_found, _} -> {:error, :not_initialized}
      {:error, _kind, _detail} = error -> api_error(ctx, error)
    end
  end

  defp iterations_for(profile, ctx, opts, api) do
    from_profile = (profile["kdf"] || %{})["iterations"]

    cond do
      is_integer(from_profile) and from_profile > 0 ->
        {:ok, from_profile}

      true ->
        case fetch_config(ctx, opts, api) do
          {:ok, %{"kdf" => %{"iterations" => iters}}} when is_integer(iters) ->
            {:ok, iters}

          _ ->
            {:error, "無法取得 KDF 迭代數（profile 與 /vault/config 皆未提供）", 6}
        end
    end
  end

  defp unlock_with_password(ctx, profile, opts, api) do
    wrapped = profile["wrapped_user_password"]

    cond do
      blank?(wrapped) ->
        {:error, "此 vault 未設定主密碼包裝金鑰（可能僅綁定助記詞）；請用 bear vault rescue", 1}

      true ->
        with {:ok, password} <- prompt_secret(opts, "主密碼"),
             {:ok, iterations} <- iterations_for(profile, ctx, opts, api) do
          master = Crypto.derive_master_key(password, ctx.email, iterations)

          case Crypto.unwrap_user_key(wrapped, master) do
            {:ok, k_user} -> {:ok, k_user}
            {:error, :invalid} -> {:error, "主密碼不正確", 1}
          end
        end
    end
  end

  defp read_new_password(opts) do
    with {:ok, new} <- prompt_secret(opts, "新主密碼"),
         {:ok, confirm} <- prompt_secret(opts, "確認新主密碼") do
      if new == confirm do
        {:ok, new}
      else
        {:error, "兩次輸入的新主密碼不一致", 2}
      end
    end
  end

  # -- Session（K_user 傳遞；僅環境變數，不落盤）--

  defp session_key(opts) do
    raw = opts[:session] || System.get_env(@session_env)

    with value when is_binary(value) <- raw,
         {:ok, key} <- Base.decode64(value),
         true <- byte_size(key) == 64 do
      key
    else
      _ when raw in [nil, ""] -> nil
      _ -> :invalid
    end
  end

  defp require_session(opts) do
    case session_key(opts) do
      nil -> {:error, "此指令需要先解鎖（bear vault unlock 後匯入 #{@session_env}）", 2}
      :invalid -> {:error, "#{@session_env} 內容無效（需 vault unlock 產生的 base64 金鑰）", 2}
      key -> {:ok, key}
    end
  end

  # -- 互動輸入 --

  # 敏感輸入（主密碼、助記詞、項目密碼）：不回顧；非 TTY → 2。
  defp prompt_secret(opts, label) do
    tty? = Map.get(opts, :tty?, true)
    io = opts[:io]

    cond do
      not tty? ->
        {:error, "此指令需要互動輸入（#{label}），請在終端機執行", 2}

      io ->
        case io.prompt_secret(label) do
          :eof -> {:error, "未讀到輸入（#{label}）", 2}
          {:ok, value} -> {:ok, value}
        end

      true ->
        if tty_stdin?() do
          case IO.gets("#{label}：") do
            :eof -> {:error, "未讀到輸入（#{label}）", 2}
            line -> {:ok, String.trim(line)}
          end
        else
          {:error, "此指令需要互動輸入（#{label}），請在終端機執行", 2}
        end
    end
  end

  # 一般輸入（名稱、備註等非敏感欄位）：可回顯；fake io 亦走 prompt/2。
  defp prompt(opts, label, default \\ nil) do
    tty? = Map.get(opts, :tty?, true)
    io = opts[:io]
    hint = if default && default != "", do: "（直接 Enter 保留 #{default}）", else: ""

    cond do
      not tty? ->
        {:error, "此指令需要互動輸入（#{label}），請在終端機執行", 2}

      io ->
        case io.prompt("#{label}#{hint}") do
          :eof -> {:error, "未讀到輸入（#{label}）", 2}
          {:ok, ""} -> {:ok, default || ""}
          {:ok, value} -> {:ok, value}
        end

      true ->
        if tty_stdin?() do
          case IO.gets("#{label}#{hint}：") do
            :eof -> {:error, "未讀到輸入（#{label}）", 2}
            line -> {:ok, String.trim(line)}
          end
        else
          {:error, "此指令需要互動輸入（#{label}），請在終端機執行", 2}
        end
    end
  end

  defp tty_stdin?, do: match?({:ok, _}, :io.rows())

  defp require_nonempty(""), do: {:error, "不可空白", 2}
  defp require_nonempty(value) when is_binary(value), do: :ok

  # -- 建立／編輯的欄位提示 --

  # 回 plaintext attrs（name 必填；其餘可空 → nil）
  defp prompt_cipher_fields(opts, type) do
    with {:ok, name} <- prompt(opts, "名稱"),
         :ok <- require_nonempty(name) do
      case type do
        "login" ->
          with {:ok, username} <- prompt(opts, "帳號（username）"),
               {:ok, password} <- prompt_secret(opts, "密碼"),
               {:ok, uri} <- prompt(opts, "URI（多個以逗號分隔，可省略）"),
               {:ok, notes} <- prompt(opts, "備註（可省略）") do
            {:ok,
             %{
               "name" => name,
               "username" => empty_to_nil(username),
               "password" => empty_to_nil(password),
               "uris" => split_uris(uri),
               "notes" => empty_to_nil(notes)
             }}
          end

        "secure_note" ->
          with {:ok, notes} <- prompt(opts, "筆記內容") do
            {:ok, %{"name" => name, "notes" => empty_to_nil(notes)}}
          end

        extra_type when extra_type in ~w(card identity) ->
          with {:ok, extra} <- prompt(opts, "額外資訊（卡號／身分資料；會加密存放）") do
            {:ok, %{"name" => name, "extra" => empty_to_nil(extra)}}
          end
      end
    end
  end

  # 編輯：解密現值 → 逐欄提示（Enter 保留現值）→ 只有變更的欄位重加密。
  defp prompt_edit_fields(opts, cipher, k_user) do
    current = decrypt_fields(cipher, k_user)

    with {:ok, name} <- prompt(opts, "名稱", current["name"]),
         :ok <- require_nonempty(name) do
      type = cipher["cipher_type"]

      attrs =
        case type do
          "login" ->
            with {:ok, username} <- prompt(opts, "帳號（username）", current["username"]),
                 {:ok, password} <- prompt_edit_secret(opts, "密碼"),
                 {:ok, uri} <- prompt(opts, "URI（逗號分隔）", Enum.join(current["uris"] || [], ",")),
                 {:ok, notes} <- prompt(opts, "備註", current["notes"]) do
              %{
                "name" => name,
                "username" => empty_to_nil(username),
                # Enter 保留現值：以解密後的現值重加密（新 IV，同一明文）
                "password" => if(password == "", do: current["password"], else: password),
                "uris" => split_uris(uri),
                "notes" => empty_to_nil(notes)
              }
            end

          "secure_note" ->
            with {:ok, notes} <- prompt(opts, "筆記內容", current["notes"]) do
              %{"name" => name, "notes" => empty_to_nil(notes)}
            end

          _ ->
            with {:ok, extra} <- prompt(opts, "額外資訊", current["extra"]) do
              %{"name" => name, "extra" => empty_to_nil(extra)}
            end
        end

      case attrs do
        {:error, _m, _c} = err -> err
        map -> {:ok, map}
      end
    end
  end

  # 編輯時的密碼欄：不回顯；直接 Enter＝保留現值（回 ""）。
  defp prompt_edit_secret(opts, label) do
    tty? = Map.get(opts, :tty?, true)
    io = opts[:io]

    cond do
      not tty? -> {:error, "此指令需要互動輸入（#{label}），請在終端機執行", 2}
      io -> io.prompt_secret("#{label}（直接 Enter 保留現值）")
      true -> prompt_secret(opts, "#{label}（直接 Enter 保留現值）")
    end
  end

  defp split_uris(""), do: []
  defp split_uris(nil), do: []

  defp split_uris(uri_string) do
    uri_string
    |> String.split(~r/[,;\s]+/, trim: true)
    |> Enum.reject(&(&1 == ""))
  end

  defp empty_to_nil(""), do: nil
  defp empty_to_nil(value), do: value

  # plaintext attrs → 加密 attrs（多餘鍵留在 data；敏感欄位逐欄加密）。
  defp encrypt_attrs(attrs, k_user) do
    Enum.reduce(attrs, %{}, fn {key, value}, acc ->
      case key do
        "extra" ->
          data = Map.get(acc, "data") || %{}

          Map.put(acc, "data", Map.put(data, "extra", value && Crypto.encrypt(value, k_user)))

        key when key in ~w(name username password notes) ->
          Map.put(acc, key, value && Crypto.encrypt(value, k_user))

        "uris" ->
          Map.put(acc, "uris", Enum.map(value || [], &Crypto.encrypt(&1, k_user)))

        _ ->
          Map.put(acc, key, value)
      end
    end)
  end

  defp decrypt_fields(cipher, k_user) do
    %{
      "name" => decrypt_to(cipher["name"], k_user, ""),
      "username" => decrypt_to(cipher["username"], k_user, ""),
      "password" => decrypt_to(cipher["password"], k_user, ""),
      "notes" => decrypt_to(cipher["notes"], k_user, ""),
      "extra" => decrypt_to((cipher["data"] || %{})["extra"], k_user, ""),
      "uris" =>
        Enum.map(cipher["uris"] || [], &decrypt_to(&1, k_user, ""))
        |> Enum.reject(&(&1 == ""))
    }
  end

  defp decrypt_to(nil, _k_user, default), do: default
  defp decrypt_to(_value, nil, _default), do: nil

  defp decrypt_to(value, k_user, default) when is_binary(value) do
    case Crypto.decrypt(value, k_user) do
      {:ok, plain} -> plain
      {:error, :invalid} -> default
    end
  end

  # -- 輸出 --

  defp cipher_row(cipher, k_user, folder_names) do
    name =
      cond do
        k_user == nil -> "(未解密)"
        true -> decrypt_to(cipher["name"], k_user, "(無法解密)")
      end

    folder_uuid = (cipher["data"] || %{})["folder_uuid"]

    [
      cipher["cipher_uuid"],
      name,
      cipher["cipher_type"],
      folder_names[folder_uuid] || "",
      cipher["revision_date"] || cipher["updated_at"] || "",
      if(cipher["deleted_at"], do: "回收桶", else: "有效")
    ]
  end

  defp cipher_json(cipher, k_user, folder_names \\ %{})

  defp cipher_json(cipher, nil, _folder_names), do: cipher

  defp cipher_json(cipher, k_user, folder_names) do
    folder_uuid = (cipher["data"] || %{})["folder_uuid"]

    Map.merge(cipher, %{
      "plain" =>
        %{
          "name" => decrypt_to(cipher["name"], k_user, nil),
          "username" => decrypt_to(cipher["username"], k_user, nil),
          "password" => decrypt_to(cipher["password"], k_user, nil),
          "notes" => decrypt_to(cipher["notes"], k_user, nil),
          "uris" => Enum.map(cipher["uris"] || [], &decrypt_to(&1, k_user, nil))
        }
        |> Map.put("folder_name", folder_names[folder_uuid])
    })
  end

  # get 指令的輔助（k_user 或 nil；資料夾名不存在）
  defp k_key_or_map(_cipher, k_user), do: k_user
  defp k_key(_value, k_user), do: k_user
  defp k_key_any([], _k_user), do: nil
  defp k_key_any(_folders, k_user), do: k_user

  defp print_cipher(cipher, k_user) do
    IO.puts("#{String.pad_trailing("UUID", 12)}: #{cipher["cipher_uuid"]}")
    IO.puts("#{String.pad_trailing("類型", 12)}: #{cipher["cipher_type"]}")
    IO.puts("#{String.pad_trailing("狀態", 12)}: #{if cipher["deleted_at"], do: "回收桶", else: "有效"}")
    IO.puts("#{String.pad_trailing("最愛", 12)}: #{cipher["favorite"]}")

    if k_user do
      fields = decrypt_fields(cipher, k_user)

      IO.puts("#{String.pad_trailing("名稱", 12)}: #{fields["name"]}")
      IO.puts("#{String.pad_trailing("帳號", 12)}: #{fields["username"] || "(無)"}")

      IO.puts(
        "#{String.pad_trailing("密碼", 12)}: #{fields["password"] || decrypt_to(cipher["password"], nil, "(無)")}"
      )

      uris = fields["uris"]

      IO.puts(
        "#{String.pad_trailing("URI", 12)}: #{if uris == [], do: "(無)", else: Enum.join(uris, "、")}"
      )

      IO.puts("#{String.pad_trailing("備註", 12)}: #{fields["notes"] || "(無)"}")

      extra = fields["extra"]
      if extra, do: IO.puts("#{String.pad_trailing("額外資訊", 12)}: #{extra}")
    else
      Enum.each(~w(name username password notes), fn field ->
        IO.puts("#{String.pad_trailing(field, 12)}: #{cipher[field] || "(未提供)"}")
      end)
    end

    IO.puts(
      "#{String.pad_trailing("修訂時間", 12)}: #{cipher["revision_date"] || cipher["updated_at"] || ""}"
    )
  end

  defp render_rows(rows, headers) do
    widths =
      Enum.with_index(headers, fn _h, i ->
        Enum.max([
          String.length(Enum.at(headers, i))
          | Enum.map(rows, &String.length(Enum.at(&1, i) || ""))
        ])
      end)

    render = fn cells ->
      cells
      |> Enum.with_index()
      |> Enum.map(fn {cell, i} ->
        String.pad_trailing(to_string(cell || ""), Enum.at(widths, i))
      end)
      |> Enum.join("  ")
      |> String.trim_trailing()
    end

    IO.puts(render.(headers))
    Enum.each(rows, &IO.puts(render.(&1)))
  end

  defp confirm_purge(opts, uuid) do
    with {:ok, answer} <- prompt(opts, "永久刪除 #{uuid}？（y/N）") do
      if answer in ~w(y Y yes YES) do
        :ok
      else
        {:error, "已取消", 1}
      end
    end
  end

  defp new_uuid do
    Base.url_encode64(:crypto.strong_rand_bytes(16), padding: false)
  end

  # -- API 錯誤處理（退出碼對應 §3.11）--

  defp wrap_api(result, ctx, _opts) do
    case result do
      {:ok, body} ->
        {:ok, body}

      {:error, _kind, _detail} = error ->
        api_error(ctx, error)
    end
  end

  defp api_error(_ctx, {:error, :unauthorized, desc}),
    do: {:error, "token 無效或已過期（#{desc}），請重新 bear login", 3}

  defp api_error(_ctx, {:error, :forbidden, desc}), do: {:error, "權限不足（HTTP 403：#{desc}）", 8}
  defp api_error(_ctx, {:error, :not_found, _desc}), do: {:error, "找不到目標（HTTP 404）", 1}

  defp api_error(_ctx, {:error, :unprocessable_entity, %{"errors" => errors} = body})
       when map_size(body) <= 2 do
    details =
      errors
      |> Enum.map(fn {field, messages} -> "#{field}: #{Enum.join(List.wrap(messages), "、")}" end)
      |> Enum.join("；")

    {:error, "驗證失敗（HTTP 422）：#{details}", 1}
  end

  defp api_error(_ctx, {:error, :unprocessable_entity, body}) when is_map(body) do
    desc = body["error_description"] || body["error"] || ""
    {:error, "驗證失敼（HTTP 422）#{if desc != "", do: "：#{desc}"}", 1}
  end

  defp api_error(_ctx, {:error, :too_many_requests, _body}),
    do: {:error, "請求過於頻繁（HTTP 429），請稍後再試", 1}

  defp api_error(_ctx, {:error, :server_error, status}), do: {:error, "伺服器回應 #{status}", 6}

  defp api_error(ctx, {:error, :network, reason}),
    do: {:error, "無法連線到 #{ctx.issuer}：#{reason}", 6}

  defp fail_api(opts, ctx, error) do
    case api_error(ctx, error) do
      {:error, message, code} -> fail(opts, message, code)
    end
  end

  defp fail(opts, message, code) do
    if opts[:json] do
      IO.puts(Jason.encode!(%{ok: false, error: message, code: code}))
    else
      IO.puts(:stderr, "錯誤：#{message}")
    end

    code
  end

  defp json?(opts), do: opts[:json] == true

  defp blank?(nil), do: true
  defp blank?(""), do: true
  defp blank?(_), do: false
end