feat: Implement comprehensive event emission system

[pushkarm029]

Pull Request Description

📋 Basic Information

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 📚 Documentation update

Related Issues

Closes #86

Priority Level

• 🟡 High (significant impact)

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📝 Detailed Description

What does this PR do?

Implements a comprehensive event emission system for the Predictify prediction market contract. Adds complete event tracking for all critical contract operations including market creation, voting, oracle results, disputes, fee collection, state changes, winnings claims, and error events.

Why is this change needed?

The contract previously lacked a systematic event emission infrastructure. This prevented:

• Real-time monitoring of contract activities
• Audit trail creation for compliance
• External integrations via event-driven architecture
• User activity tracking and analytics
• Transparent state change tracking

How was this tested?

cargo test
# Result: 202 tests passed; 0 failed; 0 ignored; finished in 46.51s

cargo build
# Result: SUCCESS (255 warnings, 0 errors)

cargo fmt --all
# Result: Code formatted successfully

cargo clippy
# Result: 437 warnings, 0 errors

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🏗️ Smart Contract Specific

Contract Changes

• Events added/modified
• Core contract logic modified (event integration)
• Oracle integration changes (oracle result events)

Oracle Integration

• Oracle configuration changes (event emission)
• Price feed handling modified (oracle result events)

Market Resolution Logic

• Hybrid resolution algorithm changed (added event emissions)
• Dispute mechanism modified (dispute event emission)
• Fee structure updated (fee collection events)
• Voting mechanism changes (vote cast events)

Security Considerations

• Access control reviewed (no changes to access control)
• Input validation (events use existing validated data)

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🧪 Testing

Test Coverage

• All tests passing locally
• Manual testing completed
• Edge cases covered

Test Results

cargo test
test result: ok. 202 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 46.51s

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📚 Documentation

Documentation Updates

• Code comments added/updated (comprehensive documentation for all new event functions)

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🔍 Code Quality

Code Review Checklist

• Code follows Rust/Soroban best practices
• Self-review completed
• Error handling is appropriate
• Code is readable and well-commented
• Variable names are descriptive
• Functions are focused and small

Performance Impact

• Gas Usage: Minimal increase (event storage operations added)
• Storage Impact: Event data stored using Soroban's efficient storage mechanisms
• Computational Complexity: O(1) for event emissions

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📊 Impact Assessment

User Impact

• End Users: Enhanced transparency - all actions now emit trackable events
• Developers: Complete event-driven integration capabilities
• Admins: Full audit trail and monitoring capabilities

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✅ Final Checklist

Pre-Submission

• Code follows Rust/Soroban best practices
• All CI checks passing
• No breaking changes
• Ready for review
• PR description is complete and accurate
• Test results included

Review Readiness

• Self-review completed
• Code is clean and well-formatted
• Commit messages are clear and descriptive

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🔗 Implementation Details

Files Modified:

• contracts/predictify-hybrid/src/events.rs - Added StateChangeEvent, WinningsClaimedEvent, and 3 new emission functions
• contracts/predictify-hybrid/src/lib.rs - Integrated events in create_market(), vote(), claim_winnings(), resolve_market_manual()
• contracts/predictify-hybrid/src/resolution.rs - Added event emissions for market resolution and oracle results
• contracts/predictify-hybrid/src/disputes.rs - Added dispute creation event emission
• contracts/predictify-hybrid/src/fees.rs - Added fee collection event emission

New Event Types:

1. StateChangeEvent - Tracks market state transitions
2. WinningsClaimedEvent - Tracks user payout claims

New Functions:

1. emit_state_change_event() - Emits on state transitions
2. emit_winnings_claimed() - Emits on winnings claims
3. emit_error_event() - Error tracking with full context

Event Integration Points:

Function	Location	Event Emitted
create_market()	lib.rs:253	MarketCreatedEvent
vote()	lib.rs:352	VoteCastEvent
claim_winnings()	lib.rs:467	WinningsClaimedEvent
resolve_market_manual()	lib.rs:646	MarketResolvedEvent + StateChangeEvent
resolve_market()	resolution.rs:1272	MarketResolvedEvent + StateChangeEvent
fetch_oracle_result()	resolution.rs:992	OracleResultEvent
process_dispute()	disputes.rs:850	DisputeCreatedEvent
collect_fees()	fees.rs:746	FeeCollectedEvent

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💬 Notes for Reviewers

Please pay special attention to:

• Event emission integration in main contract entry points
• State change tracking logic in resolution flows
• Error event implementation with ErrorContext support

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Thank you for your contribution to Predictify! 🚀

[pushkarm029]

@greatest0fallt1me please review

[greatest0fallt1me]

@pushkarm029 One step away from merge! Can you handle the conflicts?

[pushkarm029]

@greatest0fallt1me resolved