# `Gemini.Auth.MultiAuthCoordinator`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L1)

Coordinates multiple authentication strategies for concurrent usage.

Enables per-request auth strategy selection while maintaining
independent credential management and request routing.

This module serves as the central coordination point for the Gemini Unified
Implementation's multi-auth capability, allowing applications to use both
Gemini API and Vertex AI authentication strategies simultaneously.

# `auth_result`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L19)

```elixir
@type auth_result() :: {:ok, auth_strategy(), headers :: list()} | {:error, term()}
```

# `auth_strategy`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L17)

```elixir
@type auth_strategy() :: :gemini | :vertex_ai
```

# `credentials`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L18)

```elixir
@type credentials() :: map()
```

# `request_opts`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L20)

```elixir
@type request_opts() :: keyword()
```

# `coordinate_auth`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L49)

```elixir
@spec coordinate_auth(auth_strategy(), request_opts()) :: auth_result()
```

Coordinates authentication for the specified strategy.

This is the main entry point for multi-auth coordination. It routes
authentication requests to the appropriate strategy while maintaining
independent credential management.

## Parameters
- `strategy`: The authentication strategy (`:gemini` or `:vertex_ai`)
- `opts`: Request options (may include configuration overrides)

## Returns
- `{:ok, strategy, headers}` on successful authentication
- `{:error, reason}` on authentication failure

## Examples

    # Coordinate Gemini API authentication
    {:ok, :gemini, headers} = MultiAuthCoordinator.coordinate_auth(:gemini, [])
    
    # Coordinate Vertex AI authentication
    {:ok, :vertex_ai, headers} = MultiAuthCoordinator.coordinate_auth(:vertex_ai, [])
    
    # With configuration overrides
    {:ok, :gemini, headers} = MultiAuthCoordinator.coordinate_auth(:gemini, [api_key: "override"])

# `get_credentials`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L90)

```elixir
@spec get_credentials(auth_strategy(), request_opts()) ::
  {:ok, credentials()} | {:error, term()}
```

Retrieves credentials for the specified authentication strategy.

Loads credentials from configuration, with optional overrides from request options.

## Parameters
- `strategy`: The authentication strategy
- `opts`: Optional configuration overrides

## Returns
- `{:ok, credentials}` on success
- `{:error, reason}` on failure

# `refresh_credentials`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L196)

```elixir
@spec refresh_credentials(auth_strategy()) :: {:ok, credentials()} | {:error, term()}
```

Refreshes credentials for the specified authentication strategy.

For strategies that support credential refresh (like Vertex AI OAuth tokens),
this function will generate fresh credentials. For strategies that don't
need refresh (like Gemini API keys), it returns the existing credentials.

## Parameters
- `strategy`: The authentication strategy

## Returns
- `{:ok, refreshed_credentials}` on success
- `{:error, reason}` on failure

# `validate_auth_config`
[🔗](https://github.com/nshkrdotcom/gemini_ex/blob/v0.11.0/lib/gemini/auth/multi_auth_coordinator.ex#L135)

```elixir
@spec validate_auth_config(auth_strategy()) :: :ok | {:error, term()}
```

Validates configuration for the specified authentication strategy.

Checks that all required configuration is present and valid for the
given strategy.

## Parameters
- `strategy`: The authentication strategy to validate

## Returns
- `:ok` if configuration is valid
- `{:error, reason}` if configuration is invalid or missing

---

*Consult [api-reference.md](api-reference.md) for complete listing*