Stream swap quotes

[0xh3rman]

Changes

• Stream swap quotes progressively instead of waiting for all providers to finish
• Add getProvidersForRequest to Rust core to get eligible providers upfront
• Fetch quotes per-provider concurrently via TaskGroup + AsyncStream, yielding results as they arrive
• Sort accumulated quotes by best rate and always select the top quote
• Move SwapQuoteInput to SwapService for reuse across layers
• Handle InputAmountError prioritization (pick lowest min amount) on the iOS side

[gemini-code-assist]

Summary of Changes

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This pull request significantly refactors the swap quote fetching mechanism to provide a more responsive and robust user experience. By streaming quotes progressively and processing them concurrently, the application can display available swap options faster. It also introduces improved error handling for input amounts and centralizes key data structures for better maintainability.

Highlights

• Progressive Swap Quote Streaming: Implemented progressive streaming of swap quotes, allowing the UI to update as quotes become available from different providers, rather than waiting for all providers to respond.
• Rust Core Integration for Providers: Added a new getProvidersForRequest function to the Rust core, enabling the upfront retrieval of eligible swap providers for a given request.
• Concurrent Quote Fetching: Utilized Swift's TaskGroup and AsyncStream to fetch quotes concurrently from each provider, yielding results as they are received.
• Best Rate Quote Selection: Quotes are now accumulated, sorted by the best rate (highest toValue), and the top quote is automatically selected and applied.
• SwapQuoteInput Centralization: The SwapQuoteInput struct was moved to the SwapService package to promote reuse and better architectural organization across different layers.
• InputAmountError Prioritization: Enhanced error handling on the iOS side to prioritize and display the lowest minimum amount requirement when multiple InputAmountError instances are encountered.

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Changelog

• Features/Swap/Sources/Types/SwapFetchTrigger.swift
  • Imported SwapService to access shared swap functionalities.
• Features/Swap/Sources/Types/SwapQuoteInput.swift
  • Removed the local definition of SwapQuoteInput as it was moved to SwapService.
• Features/Swap/Sources/ViewModels/SwapSceneViewModel.swift
  • Refactored fetchQuotes to use an AsyncStream for progressive quote updates.
  • Added logic to accumulate, sort, and select the best swap quote as they arrive.
  • Implemented prioritizedSwapError to handle and prioritize InputAmountError instances.
  • Updated the usage of GemSwapperMock to align with new fetchQuotes signature.
• Features/Swap/Tests/SwapTests/SwapQuoteInputTests.swift
  • Imported SwapService to resolve dependencies for SwapQuoteInput.
• Features/Swap/Tests/SwapTests/SwapSceneViewModelTests.swift
  • Adjusted GemSwapperMock initialization to use quoteByProvider instead of quotes.
• Packages/FeatureServices/SwapService/SwapQuoteInput.swift
  • Added the SwapQuoteInput struct, centralizing its definition for reuse.
• Packages/FeatureServices/SwapService/SwapQuotesProvider.swift
  • Modified fetchQuotes to return an AsyncStream of Result<SwapperQuote, Error>.
  • Introduced fetchFromProviders to concurrently fetch quotes from multiple providers using TaskGroup.
  • Updated imports to include SwapperProviderType and remove BigInt.
• Packages/FeatureServices/SwapService/SwapService.swift
  • Imported SwapperProvider and SwapperProviderType for provider-specific operations.
  • Added getProvidersForQuote to retrieve eligible providers for a given swap request.
  • Implemented getQuoteByProvider to fetch a quote from a specific provider.
  • Created buildRequest as a private helper to construct SwapperQuoteRequest objects.
  • Removed the previous getQuotes method that returned an array of quotes.
  • Updated getQuoteData to call swapper.getQuoteData instead of swapper.fetchQuoteData.
• Packages/FeatureServices/SwapService/TestKit/GemSwapperMock.swift
  • Removed the quotes property and related initializers.
  • Updated fetchQuote to getQuote and fetchQuoteData to getQuoteData to match new protocol.
  • Added a mock implementation for getProvidersForRequest.
  • Enhanced fetchQuoteByProvider to include delay and error handling.
• core
  • Updated the core subproject commit to 4069ddaba46315f7db84597d59495c7e5684ec11.

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[gemini-code-assist]

Code Review

This pull request refactors the swap quote fetching mechanism to use a streaming approach with AsyncStream and TaskGroup, aiming to significantly improve the user experience by displaying quotes as they arrive. However, a critical resource leak has been identified in the SwapQuotesProvider.fetchQuotes method where the background task responsible for fetching quotes is not cancelled when the stream terminates, potentially leading to unnecessary resource consumption. Additionally, a couple of suggestions have been made in SwapSceneViewModel.swift to enhance code clarity and maintainability.