feat(pricing): add CoinPaprika pricing implementation

[donbagger]

Summary

Adds a CoinPaprika-backed PricingInterface implementation alongside the existing CoinGecko and DefiLlama sources, registered as "coinpaprika".

Why CoinPaprika: the ticker API is free with no API key and no sign-up, which makes it a practical primary or fallback feed for permissionless solver operators - one more independent source to chain in PricingService fallbacks. An optional api_key switches to the api-pro tier (higher limits) automatically.

Design notes:

• Mirrors coingecko.rs one-to-one so the shape is familiar: TTL price cache + short negative cache, in-flight fetch deduplication, schedule-based rate limiter with a bounded sleep cap, request timeout, custom_prices, and a token_id_map override.
• CoinPaprika ids are {symbol}-{name} shaped, so the source carries its own COINPAPRIKA_TOKEN_MAPPINGS (ETH -> eth-ethereum, USDC -> usdc-usd-coin, including a real WETH id) instead of reusing the CoinGecko-shaped DEFAULT_TOKEN_MAPPINGS.
• USD-only parity with the existing sources is kept (non-USD requests return PriceNotAvailable, same as CoinGecko).
• The ticker endpoint is per-coin (GET /v1/tickers/{coin_id}?quotes=USD), which matches how get_price already fetches - one id per call.
• Helpers are self-contained in the file rather than factored into shared infra, following the existing convention (defillama.rs does the same). Happy to extract shared plumbing in a follow-up if you'd prefer.

I work on developer relations for CoinPaprika, so flagging that interest openly. The implementation only touches the pricing crate and adds no default behavior change - nothing selects it unless configured.

Testing Process

• cargo fmt --check, cargo clippy -p solver-pricing --all-targets -- -D warnings, cargo build -p solver-pricing all clean
• cargo test -p solver-pricing: 122 passed, 0 failed (30 new tests, all offline via wiremock local servers - same-asset conversion, unsupported pairs, custom base_url retrieval, non-USD rejection, unknown token, invalid amounts, cache TTL and negative cache, in-flight dedup, rate-limit sleep cap, timeout bounds, api-pro key routing)
• Verified end-to-end against the live API with the default config before opening this PR: convert_asset("ETH","USD","1.0") -> 1642.13, wei_to_currency("1000000000000000000","USD") -> 1642.13, currency_to_wei("3000","USD") -> 1826895156733445020, and ETH/SOL correctly rejected as non-USD

Checklist

• Add a reference to related issues in the PR description. (No existing issue - this adds a new pricing source; happy to open one if you track features that way.)
• Add unit tests if applicable.

Summary by CodeRabbit

• New Features
  • Added a new CoinPaprika-based pricing provider using real-time USD quotes.
  • Enabled custom fixed per-token prices and enhanced conversion support (USD-based and wei-to-fiat via ETH/USD).
  • Included caching and concurrent request sharing to reduce redundant upstream requests.
• Bug Fixes
  • Improved behavior for unsupported pairs, unavailable conversions, and failure/timeout handling (including safer wait behavior).
• Tests
  • Added extensive coverage for configuration validation, caching/deduplication, timeouts, and conversion edge cases.
• Chores
  • Registered the new provider so it appears in the available implementations list.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: d73b7b70-b91e-4a75-8c84-adcbf68db088

📥 Commits

Reviewing files that changed from the base of the PR and between ea26106 and ad6ab36.

📒 Files selected for processing (1)

• crates/solver-pricing/src/lib.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/solver-pricing/src/lib.rs

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📝 Walkthrough

Walkthrough

This PR adds a CoinPaprika pricing provider with HTTP price fetching, caching, rate limiting, USD-only conversion rules, config validation, registry wiring, and tests. The solver-pricing library now exports and registers the provider.

Changes

CoinPaprika Pricing Provider

Layer / File(s)	Summary
Core types and shared utilities crates/solver-pricing/src/implementations/coinpaprika.rs	Adds token-symbol to coin-ID mapping constants, ticker response parsing types, time helpers, and an error-cloning helper.
Pricing logic, caching, rate limiting, dedup crates/solver-pricing/src/implementations/coinpaprika.rs	Implements CoinPaprikaPricing::new, rate limiting, cached price lookup with fresh/negative caching, per-key in-flight deduplication, HTTP ticker fetching with timeout, and get_price/get_pair_price with custom-price and USD-inversion handling.
PricingInterface implementation and wei conversion crates/solver-pricing/src/implementations/coinpaprika.rs	Implements PricingInterface including supported-pair enumeration, asset conversion, and wei/USD/Ether conversion using ETH as a bridge.
Config schema validation and registry wiring crates/solver-pricing/src/implementations/coinpaprika.rs	Adds CoinPaprikaConfigSchema validation for all config fields, CoinPaprikaPricingRegistry, and the create_coinpaprika_pricing factory.
Tests and library registration crates/solver-pricing/src/implementations/coinpaprika.rs, crates/solver-pricing/src/lib.rs	Adds tests covering config, pricing logic, caching, dedup, rate limiting, and timeouts; exports the coinpaprika module and registers CoinPaprikaPricingRegistry in get_all_implementations(), updating the related count assertion.

Estimated code review effort: 4 (Complex) | ~60 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant CoinPaprikaPricing
  participant Cache
  participant CoinPaprikaAPI

  Caller->>CoinPaprikaPricing: get_pair_price(base, quote)
  CoinPaprikaPricing->>Cache: get_cached_price_if_fresh(key)
  alt cache hit
    Cache-->>CoinPaprikaPricing: cached price
  else cache miss
    CoinPaprikaPricing->>CoinPaprikaPricing: apply_rate_limit()
    CoinPaprikaPricing->>CoinPaprikaAPI: fetch ticker (with timeout)
    CoinPaprikaAPI-->>CoinPaprikaPricing: price or error
    CoinPaprikaPricing->>Cache: write success/failure result
  end
  CoinPaprikaPricing-->>Caller: price or PriceNotAvailable

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Possibly related PRs

• openintentsframework/oif-solver#278: Also changes crates/solver-pricing/src/lib.rs implementation registration by adding a new pricing provider to get_all_implementations().

Suggested reviewers: shahnami, pepebndc, NicoMolinaOZ

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and clearly states the main change: adding a CoinPaprika pricing implementation.
Description check	✅ Passed	The PR description matches the required template and includes summary, testing, and checklist items.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[nahimterrazas]

Thanks for your contributions @donbagger!

Approving it.

[codecov]

Codecov Report

❌ Patch coverage is 89.04268% with 95 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
.../solver-pricing/src/implementations/coinpaprika.rs	88.9%	95 Missing ⚠️

📢 Thoughts on this report? Let us know!

[nahimterrazas]

@donbagger, Commits must have verified signatures to merge the PR. Please rebase your commits so we can merge it. Thanks!

[donbagger]

Done! Rebased onto latest main as a single signed commit (ea26106, signature shows verified). The tree is byte-identical to the previously green CI state, so it should go clean. Thanks for the review!