# Project: V3 Uniform Lookup & Identity Agnostic Resolution
> **Status:** 🏗️ Implementation (Phase 1 Complete - Feb 20, 2026)
> **Goal:** Standardize all `lu_*` tables into a hierarchical, identity-agnostic system supporting Global Defaults, Account Overrides, and Object Overrides.

## 1. Executive Summary
The Aether V3 Lookup System solves the problem of varied data standards (e.g., ISO-2, ISO-3, Numeric codes) and multi-tenant customization needs. It adopts a "Deduplicated Inheritance" pattern:
- **Global Defaults:** System-wide standard records (provided by Aether).
- **Account Overrides:** Client-specific labels, sorting, or disabled states.
- **Object Overrides:** Context-specific overrides (e.g., unique labels for a specific Event or Person).

## 2. Theoretical Architecture

### 2.1 Standardized Schema Components
To ensure consistency across the ecosystem, all lookup tables will migrate toward a baseline "V3 Minimal Structure."

**Minimal Baseline Fields:**
- `id`: Internal Integer (Primary Key).
- `id_random`: Public String (ID Vision compliance).
- `account_id`: Account context (NULL = Global).
- `for_type` / `for_id`: Polymorphic Context (Optional).
- `group`: The primary business key/cluster key (e.g., 'US', 'ACTIVE'). *Note: Must be populated for hierarchy to work.*
- `name`: Primary display label.
- `description`: Detailed explanation.
- `enable`: Binary (1 = Active, 0 = Disabled). *Crucial for Negative Overrides.*
- `hide`: UI Visibility flag.
- `sort`: Ordering priority.
- `created_on` / `updated_on`: Audit timestamps.

### 2.2 Hierarchical Selection (The "Ranked" Query)
To return a complete list where overrides replace defaults without duplication, we use **Window Functions** (`ROW_NUMBER() OVER`).

**Finalized SQL Pattern:**
```sql
SELECT * FROM (
    SELECT *, 
           ROW_NUMBER() OVER (
               PARTITION BY `group` 
               ORDER BY 
                  (for_type = :for_type AND for_id = :for_id) DESC,
                  (account_id = :account_id) DESC, 
                  created_on DESC
           ) as rank_priority
    FROM `v_lu_v3_example`
    WHERE (for_type = :for_type AND for_id = :for_id)
       OR account_id = :account_id 
       OR account_id IS NULL
) AS ranked
WHERE rank_priority = 1
  AND enable = 1 -- Negative Override enforcement
ORDER BY sort ASC, name ASC;
```

### 2.3 Identity Agnostic Resolution
To support external systems using different coding standards, the V3 API implements a multi-field "Any-Match" resolver.

**Resolution Logic:**
- Accepts a query string `q`.
- Iterates through `searchable_fields` defined in the lookup registry.
- Returns the highest-priority hierarchical match.

### 2.4 Negative Overrides (The "Shadowing" Pattern)
To "delete" a global default for a specific account, the account creates an override record with the same `group` but `enable = 0`. The ranking query assigns `rank_priority = 1` to the account record, and the outer `WHERE enable = 1` then excludes it, effectively hiding the item for that account.

---

## 3. Implementation Standards

### 3.1 Normalization Rules
- **Underscore Naming:** All database columns must use underscores (e.g., `alpha_3_code`) instead of hyphens to ensure clean Python attribute access.
- **Group Population:** The `group` field must be physically populated in the table with a stable identity string (ISO codes, standard names).
- **Physical Name Field:** While specialized fields (like `english_short_name`) may exist, a physical `name` field is required for Generic CRUD compatibility.

### 3.2 View Requirements
- **Standard Joins:** All `v_lu_v3_*` views must join the `account` table to provide `account_id_random`.
- **Hybrid Naming:** (Proposed) Views may use `COALESCE` to provide a default `name` from specialized fields if the physical `name` column is empty.

---

## 4. Implementation Roadmap

### Phase 1: Normalization & Infrastructure
- [x] Audit first batch of `lu_*` tables.
- [x] Establish `Lookup_Base` Pydantic models.
- [x] Implement hierarchical `get_lookup_list_v3` logic.
- [x] Register `/v3/lookup/` router.

### Phase 2: Migration (Batch 1: High Priority)
- [x] `lu_v3_country` (Group: `alpha_2_code`)
- [x] `lu_v3_country_subdivision` (Group: `code`)
- [x] `lu_v3_time_zone` (Group: `name`)

### Phase 3: Migration (Batch 2: Contextual)
- [ ] `lu_post_topic`
- [ ] `lu_user_status`
- [ ] `lu_file_purpose`

### Phase 4: Advanced Features
- [ ] Implement **Whitelist Policies** via `data_store` JSON.
- [ ] Implement Batch Update tools for managers.

## 5. Key Learnings & Decisions
- **Deduplication:** The `PARTITION BY group` is the cornerstone of the system. Without a populated `group` field, the hierarchy collapses.
- **Generic CRUD Compatibility:** We decided to maintain a physical `name` field to allow the Aether V3 UI to handle all lookups with zero custom code.
- **Fail-Closed:** Account isolation is enforced at the query level via the `account_id` filter.

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*Created by Gemini CLI for Scott Idem*