%%{init: { "sequence": { "wrap": true, "width":500 } } }%%
sequenceDiagram
    participant Edusharing as Edusharing Server
    participant Browser as Serlo Editor in Browser
    participant Editor as Serlo Editor Server

    Note over Browser: Trigger: User clicks button "embed content from edusharing" within plugin. Then, an iframe is created and the following exchange happens within.

    Browser->>Editor: GET /lti/start-edusharing-deeplink-flow
    
    Editor->>Browser: "Login Request" auto form
    
    Browser->>Edusharing: Form is automatically submitted<br/>GET {edusharing}/rest/lti/v13/oidc/login_initiations
    
    Edusharing->>Browser: "Authentication Request" auto form

    Browser->>Editor: Form is automatically submitted<br/>GET /platform/login

    Editor->>Browser: "Authentication Response containing LTI Deep Linking Request" auto form<br/> id_token is sent along with it.

    Browser->>Edusharing: Form is automatically submitted<br/>POST {edusharing}/rest/lti/v13/lti13

    Edusharing->>Editor: GET /platform/keys

    Editor->>Edusharing: Public keys to check it_token signature

    Edusharing->>Browser: Redirect to {edusharing}/components/search

    Note over Browser: Edusharing presents the user with possible resources to embed. Blocks until user made a selection. 

    Browser->>Editor: "LTI Deep Linking Response"<br/>POST /platform/done<br/> JWT is sent along containing nodeId that was selected by user

    Editor->>Edusharing: GET /edu-sharing/rest/lti/v13/jwks

    Edusharing->>Editor: Public keys to check JWT

    Editor->>Browser: HTML containing script that sends repositoryId and nodeId to the parent of the iframe. 

    Note over Browser: Iframe is closed. Editor edu-sharing plugin continues now. 

    Browser->>Editor: GET /lti/get-embed-html

    Editor->>Edusharing: GET /edu-sharing/rest/lti/v13/details/local/{nodeId}<br/> jwt is sent along

    Edusharing->>Editor: GET /platform/keys

    Editor->>Edusharing: Public keys to check jwt signature 

    Edusharing->>Editor: HTML snippet

    Editor->>Browser: HTML snippet

    Note over Browser: Resource that was selected by the user is displayed within the editor plugin frame. 

%%{init: { "sequence": { "wrap": true, "width":500 } } }%%
sequenceDiagram
    participant Edusharing as Edusharing Server
    participant Browser as Serlo Editor in Browser
    participant Editor as Serlo Editor Server

    Note over Browser: Trigger: User clicks button "embed content from edusharing" within plugin. Then, an iframe is created and the following exchange happens within.

    Browser->>Editor: GET /lti/start-edusharing-deeplink-flow<br/>+ltik +{cookies set by lti.js during editor LTI launch}
    
    Note over Editor: Checks: <br/>Are ltik & cookies valid? (within lti.js) <br/>Does LTI custom claim have expected type? <br/>Then: <br/>Creates session in database (deeplinkLoginData) using user, nodeId, dataToken. 
    
    Editor->>Browser: "Login Request" auto form<br/>+iss, +target_link_uri, +login_hint,<br/> +client_id=editor, +lti_deployment_id=2
    
    Browser->>Edusharing: Form is automatically submitted<br/>GET {edusharing}/rest/lti/v13/oidc/login_initiations
    
    Note over Edusharing: Checks: <br/>Is iss & client_id allowed to launch Edusharing as tool? <br/>Is target_link_uri the correct lti launch uri of this tool?
    
    Edusharing->>Browser: "Authentication Request" auto form <br/>+scope=openid, +response_type=id_token, +client_id=editor, <br/>+login_hint, +state, +response_mode=form_post, <br/>+nonce, +prompt=none, +redirect_uri={edusharing}/rest/lti/v13/lti13

    Note over Browser: Cookie for edu-sharing session is set. 

    Browser->>Editor: Form is automatically submitted<br/>GET /platform/login <br/>+{session cookies set by lti.js}

    Note over Editor: Checks: <br/>Is there a valid session (deeplinkLoginData) in the database with id login_hint? <br/>Is this client_id and redirect_uri allowed to launch as a tool on this platform? <br/>Then: <br/>Add nonce to database. <br/>Create and sign id_token

    Editor->>Browser: "Authentication Response containing LTI Deep Linking Request" auto form<br/>+id_token, +state

    Browser->>Edusharing: Form is automatically submitted<br/>POST {edusharing}/rest/lti/v13/lti13 <br/>+{session cookies set by edu-sharing}

    Note over Edusharing: Checks: <br/>Does state match what was sent? <br/>Does nonce value in id_token match what was sent? <br/>Is iss allowed?

    Edusharing->>Editor: GET /platform/keys

    Editor->>Edusharing: Public keys to check it_token signature

    Note over Edusharing: Checks: <br/>Is id_token signature valid? <br/>

    Edusharing->>Browser: Redirect to {edusharing}/components/search

    Note over Browser: Edusharing presents the user with possible resources to embed. Blocks until user made a selection. 

    Browser->>Editor: "LTI Deep Linking Response" containing nodeId that was selected by user to embed<br/>POST /platform/done<br/>+JWT +{session cookies set by lti.js}

    Note over Editor: Checks: <br/>Is nonce in JWT found in database. 

    Editor->>Edusharing: GET /edu-sharing/rest/lti/v13/jwks

    Edusharing->>Editor: Public keys to check jwt

    Note over Editor: Checks: <br/>Is JWT signature valid? 

    Editor->>Browser: HTML containing script that sends repositoryId and nodeId to the parent of the iframe. 

    Note over Browser: Iframe is closed. Editor edu-sharing plugin continues now. 

    Browser->>Editor: GET /lti/get-embed-html<br/>+nodeId, +repositoryId<br/>+Authorization: Bearer {ltik}, +{session cookies set by lti.js}

    Editor->>Edusharing: GET /edu-sharing/rest/lti/v13/details/local/{nodeId}<br/>+displayMode=inline, +jwt

    Edusharing->>Editor: GET /platform/keys

    Editor->>Edusharing: Public keys to check jwt signature 

    Note over Edusharing: Checks: <br/>Is jwt signature valid?

    Edusharing->>Editor: HTML snippet

    Editor->>Browser: HTML snippet

    Note over Browser: Resource that was selected by the user is displayed within the editor plugin frame.