# LeaP Refactor

## Concepts and assumptions

* Holochain is a big [CRDT](https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type) -> you can only update an entry once
* Update chains cannot have cycles
* Original entry does not have link to the latest version of the entry (so it's slow to go through them all)

## Entries

Entry "course" {
    Model: struct Course {
        timestamp: u64,
        teacher_address: Address,
    }
    Links: {
        course->student
        student->course
        teacher->course
    }
}

Entry "course_modules" {
    Model: struct CourseModules {
        course_address: Address, // Address of the anchor!
        title: String,
        modules: Vec<Address>,
        last_header_address: Option<Address>,
    }
}

Entry "module" {
    Model: struct Module {
        title: String,
        course_address: Address, // Address of the anchor!
        timestamp: u64
    }
    Links: {
        module->contents
    }
}

Entry "content" {
    Model: struct Content {
        name: String,
        descritpion: String,
        url: String,
        timestamp: u64,
        module_address: Address
    }
}

## Entry relationship diagram

graph LR
  subgraph Courses zome
    
    subgraph agent_id
      bob_id
      alice_id
    end
    subgraph anchors
      all_courses
    end
    subgraph courses
        Course1
    end
    subgraph course_modules
      Course1 -->|last_version| CourseModules1v0
      Course1 -->|last_version| CourseModules1v1
      CourseModules1v0 ==>|replaced_by| CourseModules1v1
    end
    subgraph modules
      Module1
    end
    subgraph content
      Content1
    end
    
    all_courses --> Course1
    CourseModules1v0 -.->|modules| Module1
    Module1 -.->|course_address| Course1
    Course1 -.teacher.-> alice_id
    bob_id -->|student->courses| Course1
    Course1 -->|course->students| bob_id
    alice_id -->|my_courses| Course1
      
    Module1 -->|module->contents| Content1
    Content1 -.->|module_address| Module1
            
  end