group: setting
type: process
desc: |
  Generic user personalization settings store with three-level scope hierarchy.
  Stores arbitrary JSON data organized by namespace and scope, with cascading
  merge support (system ← team ← user, later scope wins).

  Process names follow the pattern "setting.<handler>".

  Scoping model:
    Three levels, from lowest to highest priority:
    1. system — Global defaults, shared by all users.
    2. team — Team-level overrides, shared by team members.
    3. user — Individual user preferences, highest priority.

  ScopeID structure (used as argument for get, set, delete, listnamespaces):
    - scope (string, required): Scope level. Values: "system", "team", "user".
    - team_id (string): Required when scope is "team".
    - user_id (string): Required when scope is "user".
    Examples:
      System scope: {"scope":"system"}
      Team scope:   {"scope":"team","team_id":"99"}
      User scope:   {"scope":"user","user_id":"42"}

  Entry structure (returned by set):
    - namespace (string): Namespace name (e.g. "preferences", "privacy", "models").
    - scope (ScopeID): The scope this entry belongs to.
    - data (object): Arbitrary key-value data stored for this namespace.
    - updated_at (string): ISO 8601 timestamp of last update.

  Namespace convention:
    Namespaces are free-form strings chosen by the consuming module.
    Typical examples: "preferences", "privacy", "models", "notifications".
    Each namespace stores one JSON object (map of string → any).
    The registry does not enforce any schema — the consuming module defines
    the expected structure.

  Merge behavior (getmerged):
    Shallow merge across three scopes: system ← team ← user.
    For each top-level key, the highest-priority scope's value wins.
    Example:
      system: {"theme":"light","lang":"en","font_size":14}
      team:   {"lang":"zh-CN"}
      user:   {"theme":"dark"}
      merged: {"theme":"dark","lang":"zh-CN","font_size":14}
    If a scope has no data for the namespace, it is skipped.
    Returns 404 only when no data exists at any scope.

entries:
  - name: get
    desc: |
      Get a namespace entry for a specific scope. Returns the raw data object
      without any merging. Throws 404 if the namespace does not exist at
      the given scope.
    args:
      - name: scope
        type: object
        required: true
        desc: |
          ScopeID object identifying the scope.
          Examples:
            {"scope":"system"}
            {"scope":"team","team_id":"99"}
            {"scope":"user","user_id":"42"}
      - name: namespace
        type: string
        required: true
        desc: 'Namespace name (e.g. "preferences", "privacy", "models").'
    return:
      type: object
      desc: |
        The namespace data as a key-value map (not wrapped in Entry).
        Example: {"theme":"dark","lang":"zh-CN","font_size":14}

  - name: getmerged
    desc: |
      Get a namespace with three-level cascade merge: system ← team ← user.
      Reads data from all three scopes and shallow-merges them, with higher-priority
      scopes overriding lower ones. Pass empty string for userID or teamID to
      skip that scope. Throws 404 if no data exists at any scope.
    args:
      - name: userID
        type: string
        required: true
        desc: 'User ID. Pass "" (empty string) to skip user scope.'
      - name: teamID
        type: string
        required: true
        desc: 'Team ID. Pass "" (empty string) to skip team scope.'
      - name: namespace
        type: string
        required: true
        desc: Namespace name.
    return:
      type: object
      desc: |
        Shallow-merged data from all available scopes.
        Example with system={"a":"sys","b":"sys"}, team={"b":"team"}, user={"a":"user"}:
        Result: {"a":"user","b":"team"}

  - name: set
    desc: |
      Set (create or overwrite) a namespace entry for a given scope.
      Persists to __yao.store and updates __yao.cache.
      Overwrites any existing data for this scope + namespace combination.
    args:
      - name: scope
        type: object
        required: true
        desc: 'ScopeID object. Example: {"scope":"user","user_id":"42"}'
      - name: namespace
        type: string
        required: true
        desc: Namespace name.
      - name: data
        type: object
        required: true
        desc: |
          Key-value data to store. Arbitrary JSON object.
          Example: {"theme":"dark","lang":"zh-CN","font_size":14}
    return:
      type: object
      desc: |
        Entry object confirming the write. Fields:
          - namespace (string)
          - scope (ScopeID)
          - data (object): The stored data.
          - updated_at (string): ISO 8601 timestamp.
        Example: {"namespace":"preferences","scope":{"scope":"user","user_id":"42"},
          "data":{"theme":"dark","lang":"zh-CN"},"updated_at":"2025-01-15T10:30:00Z"}

  - name: delete
    desc: |
      Delete a namespace entry from a scope. Removes from __yao.store
      and __yao.cache. Throws 404 if the namespace does not exist at the scope.
    args:
      - name: scope
        type: object
        required: true
        desc: 'ScopeID object. Example: {"scope":"system"}'
      - name: namespace
        type: string
        required: true
        desc: Namespace name to delete.
    return:
      type: "null"
      desc: Returns null on success.

  - name: listnamespaces
    desc: |
      List all namespace names stored under a scope. Returns the namespace
      strings only, not the data. Use "get" to retrieve data for each namespace.
    args:
      - name: scope
        type: object
        required: true
        desc: 'ScopeID object. Example: {"scope":"team","team_id":"99"}'
    return:
      type: array
      desc: |
        Array of namespace name strings.
        Example: ["preferences","privacy","models"]
        Returns empty array if no namespaces exist for the scope.