erDiagram
    Team {
        Int id PK
    }
    
    Alias {
        Int id PK
        Int team_id FK
        String alias UK 
    }
    
    Match {
        Int id PK
        Int home_team_id FK
        Int away_team_id FK
        Date starts_at
        String result_status
    }
    
    ExternalMatch {
        Int id PK
        Int match_id FK
        Int home_score
        Int away_score
        String status
    }
    
    Subscription {
        Int id PK
        String url UK
        Int match_id FK
        String key
        String status
        String subscriber_error
        Date notified_at
        Date created_at
    }
    
    ExternalTeam {
        Int id PK
        Int team_id FK
    }
    
    CheckResultTask {
        Int id PK
        Int match_id FK
        String name UK
        Int attempt_number
        Date execute_at
        Date created_at
    }
    
    Team ||--o{ Alias : has 
    Team ||--o{ Match : has
    Match ||--|| ExternalMatch : has
    Match ||--o{ Subscription : has
    Team ||--|| ExternalTeam : has
    Match ||--|| CheckResultTask : has

flowchart TD
    subgraph Group 1
        A[Create a match] --> B[Subscribe on result receiving]
    end

    subgraph Group 2
        C[Receive trigger to check match result] --> D[Notify subscribers]
    end

    E[Delete a subscription]

    B --> C
    B --> E

sequenceDiagram
participant API as prognoz-api
participant ResultService as result-service
participant Fotmob as fotmob-api
participant CloudTasks as cloud-tasks
API->>ResultService: Sends a request to create a match
Activate ResultService
ResultService->>ResultService: Gets team ids by aliases from the DB
ResultService->>ResultService: Gets match by team ids and starting time from the DB
alt match is found and result status is scheduled
    ResultService-->>API: Returns match response
end
ResultService->>+Fotmob: Sends a request with date
Fotmob-->>-ResultService: Returns all matches for the date
ResultService->>ResultService: Finds a match in the response by aliases and starting time
ResultService->>ResultService: Saves match with status not_scheduled and external match to the DB
ResultService->>CloudTasks: Creates a task to check result with schedule-time (starting time + 115 minutes)
Activate CloudTasks
CloudTasks-->>ResultService: Returns task id
Deactivate CloudTasks
ResultService->>ResultService: Saves check result task to the DB
ResultService->>ResultService: Updates match status to scheduled
ResultService-->>API: Returns match response
Deactivate ResultService

sequenceDiagram
participant API as prognoz-api
participant ResultService as result-service
API->>ResultService: Sends a request to create subscription
Activate ResultService
ResultService->>ResultService: Gets match from the DB
alt Match result status in not scheduled
ResultService-->>API: Returns error
end
ResultService->>ResultService: Saves subscription to the DB
ResultService-->>API: Returns success
Deactivate ResultService

sequenceDiagram
    participant CloudTasks as cloud-tasks
    participant ResultService as result-service
    participant Fotmob as fotmob-api
    CloudTasks->>+ResultService: Sends a request to check match result
    ResultService->>+Fotmob: Sends a request with date
    Fotmob-->>-ResultService: Returns all matches for the date
    ResultService->>ResultService: Finds a match in the response by id
    ResultService->>ResultService: Updates external match data
    alt match is not yet ended
        ResultService->>CloudTasks: Creates a new task to check result with backoff
        ResultService-->>CloudTasks: Returns success
    end
    ResultService->>ResultService: Gets all subscriptions of the match from the DB 
    loop Each subscription
        ResultService->>CloudTasks: Create a task to notify subscriber
    end
    ResultService-->>-CloudTasks: Returns success

sequenceDiagram
    participant CloudTasks as cloud-tasks
    participant ResultService as result-service
    participant API as prognoz-api
    CloudTasks->>+ResultService: Sends a request to notify subscriber
    ResultService->>ResultService: Gets a subscription and a match from the DB
    ResultService->>+API: Sends a request with the match result
    API-->>-ResultService: Returns success
    ResultService->>ResultService: Updates subscription status
    ResultService-->>-CloudTasks: Returns success
    

sequenceDiagram
participant API as prognoz-api
participant ResultService as result-service
participant CloudTasks as cloud-tasks
API->>ResultService: Sends a request to remove subscription
Activate ResultService
ResultService->>ResultService: Deletes subscription from DB
alt other subscriptions for this match exist
ResultService-->>API: Returns success
end
ResultService->>CloudTasks: Sends a request to remove scheduled task
Activate CloudTasks
CloudTasks-->>ResultService: Returns success
Deactivate CloudTasks
ResultService->>ResultService: Removes match and fixture from DB
ResultService-->>API: Returns success
Deactivate ResultService