# Component Dependencies — Master CMS Module

## Package-Level Dependency Diagram

```mermaid
graph TD
    Api["SlpModularCms.Api\n(shell)"]
    Master["SlpModularCms.Modules.Master\n(NEW)"]
    Availability["SlpModularCms.Modules.Availability\n(EXTENDED)"]
    Core["SlpModularCms.Core\n(unchanged)"]
    Frontend["Frontend\n(EXTENDED)"]
    SlaveCms["Slave CMS\n(another SlpModularCms instance)"]

    Api --> Master
    Api --> Availability
    Api --> Core
    Master --> Core
    Availability --> Core
    Frontend -->|"REST /api/v1/*"| Api
    Master -->|"HTTP slave API calls"| SlaveCms
    SlaveCms -->|"HTTP pull master status"| Master

    classDef new fill:#9ae6b4,stroke:#2f855a,stroke-width:2px,color:#000
    classDef extended fill:#FFC107,stroke:#F57F17,stroke-width:2px,color:#000
    classDef unchanged fill:#63b3ed,stroke:#2b6cb0,stroke-width:1px,color:#000
    classDef external fill:#FC8181,stroke:#C53030,stroke-width:2px,color:#000
    class Master new
    class Availability,Frontend extended
    class Api,Core unchanged
    class SlaveCms external
```

Text alternative: Master and Availability modules both depend on Core; Api depends on all three; Frontend calls Api REST; Master calls Slave CMS via HTTP and Slave pulls back.

---

## Master-Backend Component Dependencies

```mermaid
graph TD
    Ctrl["CmsInstanceController"]
    Svc["CmsInstanceService"]
    Repo["CmsInstanceRepository"]
    DbCtx["MasterDbContext"]
    SlaveClient["SlaveApiClient"]
    BgSvc["IntegrityCheckBackgroundService"]
    Opts["MasterModuleOptions\n(IOptions)"]
    CmsEntity["CmsInstance\n(entity)"]

    Ctrl --> Svc
    Svc --> Repo
    Svc --> SlaveClient
    Svc --> Opts
    Repo --> DbCtx
    Repo --> CmsEntity
    DbCtx --> CmsEntity
    BgSvc --> Svc
    BgSvc --> Opts

    classDef controller fill:#63b3ed,stroke:#2b6cb0,stroke-width:1px,color:#000
    classDef service fill:#9ae6b4,stroke:#2f855a,stroke-width:2px,color:#000
    classDef data fill:#FFC107,stroke:#F57F17,stroke-width:2px,color:#000
    classDef infra fill:#CE93D8,stroke:#6A1B9A,stroke-width:1px,color:#000
    class Ctrl controller
    class Svc,SlaveClient service
    class Repo,DbCtx,CmsEntity data
    class BgSvc,Opts infra
```

Text alternative: Controller depends on Service; Service depends on Repository, SlaveApiClient, and Options; Repository owns DbContext and entity; BackgroundService depends on Service and Options.

---

## Slave-Availability-Extension Component Dependencies

```mermaid
graph TD
    Middleware["AvailabilityMiddleware\n(EXTENDED)"]
    LocalSvc["IAvailabilityService\n(existing)"]
    MasterSvc["MasterAvailabilityService\n(NEW)"]
    AvailDb["AvailabilityDbContext\n(NEW)"]
    MasterRegEntity["MasterRegistration\n(entity)"]
    HttpFactory["IHttpClientFactory"]
    Opts["MasterModuleOptions\n(IOptions)"]
    AvailCtrl["AvailabilityController\n(EXTENDED)"]
    MasterCms["Master CMS\n(HTTP endpoint)"]

    Middleware --> LocalSvc
    Middleware --> MasterSvc
    MasterSvc --> AvailDb
    MasterSvc --> HttpFactory
    MasterSvc --> Opts
    AvailDb --> MasterRegEntity
    AvailCtrl --> AvailDb
    AvailCtrl --> Opts
    HttpFactory -->|"HTTP GET status"| MasterCms

    classDef middleware fill:#63b3ed,stroke:#2b6cb0,stroke-width:1px,color:#000
    classDef service fill:#9ae6b4,stroke:#2f855a,stroke-width:2px,color:#000
    classDef data fill:#FFC107,stroke:#F57F17,stroke-width:2px,color:#000
    classDef infra fill:#CE93D8,stroke:#6A1B9A,stroke-width:1px,color:#000
    classDef external fill:#FC8181,stroke:#C53030,stroke-width:2px,color:#000
    class Middleware middleware
    class MasterSvc,LocalSvc service
    class AvailDb,MasterRegEntity,AvailCtrl data
    class HttpFactory,Opts infra
    class MasterCms external
```

Text alternative: Extended middleware calls both MasterAvailabilityService and existing IAvailabilityService; MasterAvailabilityService reads DB for registration and pulls from master via HTTP; AvailabilityController handles registration writes.

---

## Frontend Component Dependencies

```mermaid
graph TD
    CmsPage["CmsPage\n(/cms route)"]
    List["CmsInstanceList"]
    AddDialog["AddCmsInstanceDialog"]
    StatusDialog["SetStatusDialog"]
    HookList["useCmsInstances"]
    HookAdd["useAddCmsInstance"]
    HookStatus["useUpdateCmsInstanceStatus"]
    ApiTypes["CmsInstance types\nCmsInstanceStatus enum"]
    MasterApi["Master CMS REST API\n/api/v1/CmsInstances"]

    CmsPage --> List
    CmsPage --> AddDialog
    CmsPage --> StatusDialog
    List --> HookList
    AddDialog --> HookAdd
    StatusDialog --> HookStatus
    HookList --> ApiTypes
    HookAdd --> ApiTypes
    HookStatus --> ApiTypes
    HookList -->|"GET"| MasterApi
    HookAdd -->|"POST"| MasterApi
    HookStatus -->|"PUT"| MasterApi

    classDef page fill:#63b3ed,stroke:#2b6cb0,stroke-width:2px,color:#000
    classDef component fill:#9ae6b4,stroke:#2f855a,stroke-width:1px,color:#000
    classDef hook fill:#FFC107,stroke:#F57F17,stroke-width:1px,color:#000
    classDef types fill:#CE93D8,stroke:#6A1B9A,stroke-width:1px,color:#000
    classDef api fill:#FC8181,stroke:#C53030,stroke-width:2px,color:#000
    class CmsPage page
    class List,AddDialog,StatusDialog component
    class HookList,HookAdd,HookStatus hook
    class ApiTypes types
    class MasterApi api
```

Text alternative: CmsPage renders List + dialogs; List uses useCmsInstances; dialogs use mutation hooks; all hooks use shared API types and call Master REST API.

---

## Dependency Matrix

| Component | Depends On | Used By |
|-----------|-----------|---------|
| `CmsInstanceController` | `ICmsInstanceService` | `SlpModularCms.Api` (module registration) |
| `CmsInstanceService` | `ICmsInstanceRepository`, `ISlaveApiClient`, `IOptions<MasterModuleOptions>` | `CmsInstanceController`, `IntegrityCheckBackgroundService` |
| `CmsInstanceRepository` | `MasterDbContext` | `CmsInstanceService` |
| `MasterDbContext` | EF Core, `CmsInstance` entity | `CmsInstanceRepository` |
| `SlaveApiClient` | `HttpClient` (via `IHttpClientFactory`) | `CmsInstanceService` |
| `IntegrityCheckBackgroundService` | `IServiceScopeFactory`, `ICmsInstanceService`, `IOptions<MasterModuleOptions>` | `IHostedService` (framework) |
| `AvailabilityMiddleware` (ext.) | `IAvailabilityService`, `IMasterAvailabilityService` | ASP.NET Core pipeline |
| `MasterAvailabilityService` | `AvailabilityDbContext`, `IHttpClientFactory`, `IOptions<MasterModuleOptions>` | `AvailabilityMiddleware` |
| `AvailabilityDbContext` | EF Core, `MasterRegistration` entity | `MasterAvailabilityService`, `AvailabilityController` |
| `AvailabilityController` (ext.) | `IAvailabilityService`, `AvailabilityDbContext`, `IOptions<MasterModuleOptions>` | `SlpModularCms.Api` |
| `CmsPage` | `CmsInstanceList`, `AddCmsInstanceDialog`, `SetStatusDialog` | React Router |
| `useCmsInstances` | TanStack Query, API types | `CmsInstanceList` |
| `useAddCmsInstance` | TanStack Query, API types | `AddCmsInstanceDialog` |
| `useUpdateCmsInstanceStatus` | TanStack Query, API types | `SetStatusDialog` |

---

## Cross-Cutting Concerns

| Concern | Mechanism |
|---------|-----------|
| Authentication (API) | JWT Bearer on all master endpoints; `[Authorize(Policy = "OwnerOnly")]` on `CmsInstanceController` |
| Authentication (Slave internal) | `X-Master-Api-Key` header validated against `MasterModuleOptions.ApiKey` |
| API key secrecy | `ApiKey` never included in `CmsInstanceDto`; only in `CreateCmsInstanceRequest` input |
| Fail-open | `MasterAvailabilityService` returns cached status (default `Available`) on HTTP failure |
| Per-module migrations | `MasterDbContext` in `Modules.Master`; `AvailabilityDbContext` in `Modules.Availability`; applied at startup in `UseModule` |
| Configuration | `MasterModuleOptions` via `IOptions<MasterModuleOptions>`; section `"MasterModule"` in `appsettings.json` |