Udalov/day3

[peresvetjke]

Model Layer Implementation: Before & After

Before

• No models for Repository, UserRepository, Chat, Message, or ChatUser (except User).
• No database tables or migrations for these entities.
• No unread message tracking logic.
• No model-level tests or associations for chat/message functionality.
• Database schema included some fields and tables that were not strictly necessary for MVP (e.g., unread_messages table, private field in repositories).

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After

Models & Migrations

• Repository

  • Added model, migration, and tests.
  • Fields: github_repo_id, name, url, timestamps.
  • Associations: has_many :user_repositories, has_many :users, through: :user_repositories.
  • Removed unnecessary private field; added url for GitHub linking.

• UserRepository

  • Added model, migration, and tests.
  • Fields: user_id, repository_id, timestamps.
  • Associations: belongs_to :user, belongs_to :repository.
  • Unique index on [user_id, repository_id].

• Chat

  • Added model, migration, and tests.
  • Fields: chat_type (private/group), repository_id (nullable), timestamps.
  • Associations: belongs_to :repository, optional: true.
  • Only essential fields for MVP.

• Message

  • Added model, migration, and tests.
  • Fields: chat_id, user_id, content (max 400), timestamps.
  • Associations: belongs_to :chat, belongs_to :user.
  • Index on [chat_id, created_at] for efficient chat history queries.

• ChatUser

  • Added model, migration, and tests.
  • Fields: chat_id, user_id, last_read_message_id (nullable), timestamps.
  • Associations: belongs_to :chat, belongs_to :user, belongs_to :last_read_message, class_name: 'Message', optional: true.
  • Unique index on [chat_id, user_id].
  • Unread tracking implemented via last_read_message_id (not a separate table).

Testing

• All models are fully covered by unit tests (validations and associations).
• TDD process followed for each model.

Schema Simplification

• Removed unnecessary fields and tables (e.g., unread_messages, private in repositories, joined_at/left_at in chat_users).
• All models and tables now contain only fields required for MVP.

Documentation

• Memory bank and schema diagrams updated to reflect the new, minimal, and focused design.

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Summary Table

Model	Before	After (Fields/Associations/Indexes)
Repository	None	github_repo_id, name, url, users, user_repositories
UserRepository	None	user_id, repository_id, unique index
Chat	None	chat_type, repository_id (nullable), repository
Message	None	chat_id, user_id, content (max 400), chat, user
ChatUser	None	chat_id, user_id, last_read_message_id, unique idx

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This PR introduces a clean, minimal, and fully tested model layer for the chat application, ready for further business logic and feature development.

[madmatvey]

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