Prediction Market Contract

Overview

The PredictionMarketV2 contract manages the complete lifecycle of prediction markets, from creation through resolution and payout. It implements on-chain Levenshtein distance calculation for winner determination and features pull-based fee collection to prevent griefing attacks. Contract Address: TBD (Deployment pending)

Constants

Constant	Value	Description
`PLATFORM_FEE_BPS`	700	Platform fee in basis points (7%)
`MIN_BET`	0.001 ether	Minimum bet amount
`BETTING_CUTOFF`	1 hour	Betting closes 1 hour before market end
`MIN_SUBMISSIONS`	2	Minimum submissions required for resolution
`MAX_TEXT_LENGTH`	280	Maximum prediction text length (characters)

Market Creation

createMarket

Creates a new prediction market for a social media actor.

function createMarket(
    string calldata _actorHandle,
    uint256 _duration
) external whenNotPaused returns (uint256)

_actorHandle

string

required

Social media handle being predicted (e.g., “@elonmusk”)

_duration

uint256

required

Market duration in seconds. Must be between 1 hour and 30 days.

marketId

uint256

The ID of the newly created market

Emits: MarketCreated(uint256 indexed marketId, string actorHandle, uint256 endTime, address creator) Errors:

InvalidDuration() - Duration not between 1 hour and 30 days

Example:

// Create market for 7 days
uint256 marketId = predictionMarket.createMarket("@elonmusk", 7 days);

Submission Management

createSubmission

Submit a prediction and stake ETH on it.

function createSubmission(
    uint256 _marketId,
    string calldata _predictedText
) external payable whenNotPaused nonReentrant returns (uint256)

_marketId

uint256

required

The market ID to submit to

_predictedText

string

required

Your prediction of what the actor will say. Must be 1-280 characters.

msg.value

uint256

required

ETH amount to stake. Must be at least MIN_BET (0.001 ETH).

submissionId

uint256

The ID of the newly created submission

Emits:

SubmissionCreated(uint256 indexed submissionId, uint256 indexed marketId, address submitter, string predictedText, uint256 amount)

Errors:

MarketNotFound() - Market ID doesn’t exist
MarketAlreadyResolved() - Market already resolved
MarketEnded() - Market end time passed
BettingCutoffPassed() - Within 1 hour of market end
InsufficientBet() - Bet below minimum
EmptyPrediction() - Prediction text is empty
PredictionTooLong() - Prediction exceeds 280 characters

Example:

// Submit prediction with 0.01 ETH stake
uint256 submissionId = predictionMarket.createSubmission{value: 0.01 ether}(
    marketId,
    "gm"
);

Market Resolution

resolveMarket

Resolve a market by providing the actual text. Only callable by contract owner.

function resolveMarket(
    uint256 _marketId,
    string calldata _actualText
) external onlyOwner

_marketId

uint256

required

The market ID to resolve

_actualText

string

required

The actual text the actor posted

Emits: MarketResolved(uint256 indexed marketId, uint256 winningSubmissionId, string actualText, uint256 winningDistance) Resolution Logic:

Winner determined by minimum Levenshtein distance to actual text
First submitter wins ties (deterministic)
Requires at least 2 submissions

Errors:

MarketNotFound() - Market ID doesn’t exist
MarketAlreadyResolved() - Market already resolved
MarketNotEnded() - Market end time not reached
MinimumSubmissionsNotMet() - Less than 2 submissions

Example:

// Resolve market with actual tweet text
predictionMarket.resolveMarket(marketId, "gm frens");

Payout Claims

claimPayout

Claim payout for a winning submission.

function claimPayout(uint256 _submissionId) external nonReentrant

_submissionId

uint256

required

The submission ID to claim payout for

Emits: PayoutClaimed(uint256 indexed submissionId, address indexed claimer, uint256 amount) Payout Calculation:

Winner receives: totalPool * (100 - 7) / 100 = 93% of pool
Platform receives: totalPool * 7 / 100 = 7% fee
Fees accumulated for pull-based withdrawal

Errors:

SubmissionNotFound() - Submission ID doesn’t exist
MarketNotEnded() - Market not resolved yet
NotWinningSubmission() - Not the winning submission
AlreadyClaimed() - Payout already claimed
TransferFailed() - ETH transfer failed

Example:

// Claim payout for winning submission
predictionMarket.claimPayout(submissionId);

refundSingleSubmission

Refund the only submission when market ends with single entry. Prevents unfair fee loss when there’s no competition.

function refundSingleSubmission(uint256 _marketId) external nonReentrant

_marketId

uint256

required

The market with single submission

Emits: SingleSubmissionRefunded(uint256 indexed marketId, uint256 indexed submissionId, address submitter, uint256 amount) Errors:

MarketNotFound() - Market ID doesn’t exist
MarketAlreadyResolved() - Market already resolved
MarketNotEndedForRefund() - Market hasn’t ended yet
NotSingleSubmission() - Market has more than 1 submission
AlreadyClaimed() - Already refunded
TransferFailed() - ETH transfer failed

Fee Management

withdrawFees

Withdraw accumulated fees using pull-based pattern.

function withdrawFees() external nonReentrant

Emits: FeesWithdrawn(address indexed recipient, uint256 amount) Errors:

NoFeesToWithdraw() - No fees available for caller
TransferFailed() - ETH transfer failed

Example:

// Withdraw accumulated fees
predictionMarket.withdrawFees();

View Functions

getMarketSubmissions

Get all submission IDs for a market.

function getMarketSubmissions(uint256 _marketId) external view returns (uint256[] memory)

_marketId

uint256

required

The market ID

submissionIds

uint256[]

Array of submission IDs for the market

getUserSubmissions

Get all submission IDs for a user.

function getUserSubmissions(address _user) external view returns (uint256[] memory)

_user

address

required

The user address

submissionIds

uint256[]

Array of submission IDs for the user

getMarketDetails

Get comprehensive market information.

function getMarketDetails(uint256 _marketId) external view returns (
    string memory actorHandle,
    uint256 endTime,
    uint256 totalPool,
    bool resolved,
    uint256 winningSubmissionId,
    address creator,
    uint256[] memory submissionIds
)

_marketId

uint256

required

The market ID

actorHandle

string

The social media handle being predicted

endTime

uint256

Unix timestamp when the market ends

totalPool

uint256

Total ETH staked in the market (in wei)

resolved

bool

Whether the market has been resolved

winningSubmissionId

uint256

The winning submission ID (0 if unresolved)

creator

address

Address that created the market

submissionIds

uint256[]

All submission IDs for this market

getSubmissionDetails

Get comprehensive submission information.

function getSubmissionDetails(uint256 _submissionId) external view returns (
    uint256 marketId,
    address submitter,
    string memory predictedText,
    uint256 amount,
    bool claimed
)

_submissionId

uint256

required

The submission ID

marketId

uint256

The market this submission belongs to

submitter

address

Address that created the submission

predictedText

string

The predicted text

amount

uint256

ETH staked on this prediction (in wei)

claimed

bool

Whether payout has been claimed

Admin Functions

setFeeRecipient

Update the fee recipient address. Only callable by contract owner.

function setFeeRecipient(address _newRecipient) external onlyOwner

_newRecipient

address

required

New address to receive platform fees

pause

Pause the contract in emergency situations. Only callable by contract owner.

function pause() external onlyOwner

When paused, createMarket and createSubmission cannot be called.

unpause

Unpause the contract. Only callable by contract owner.

function unpause() external onlyOwner

emergencyWithdraw

Emergency withdraw for unresolved markets. Returns funds to submitters. Only callable by contract owner.

function emergencyWithdraw(uint256 _marketId) external onlyOwner nonReentrant

_marketId

uint256

required

The market to emergency withdraw from

Requirements:

Only callable 7 days after market end time
Market must not be resolved
Returns full stake to each submitter (no fees taken)

Errors:

MarketNotFound() - Market ID doesn’t exist
MarketAlreadyResolved() - Market already resolved
MarketNotEnded() - Not 7 days past market end

Utility Functions

levenshteinDistance

Calculate Levenshtein (edit) distance between two strings. Pure function, callable off-chain.

function levenshteinDistance(
    string memory a,
    string memory b
) public pure returns (uint256)

string

required

First string

string

required

Second string

distance

uint256

The edit distance between the strings

Gas Cost: O(m*n) where m and n are string lengths. Recommended max length: ~100 characters each. Example:

uint256 distance = predictionMarket.levenshteinDistance("hello", "hallo");
// Returns: 1

State Variables

marketCount

uint256 public marketCount

Total number of markets created (also serves as next market ID).

submissionCount

uint256 public submissionCount

Total number of submissions created (also serves as next submission ID).

markets

mapping(uint256 => Market) public markets

Mapping from market ID to Market struct.

submissions

mapping(uint256 => Submission) public submissions

Mapping from submission ID to Submission struct.

pendingFees

mapping(address => uint256) public pendingFees

Accumulated fees available for withdrawal by address.

feeRecipient

address public feeRecipient

Address designated to receive platform fees.

REST API

Contract Methods

Prediction Market Contract

Overview

Constants

Market Creation

createMarket

Submission Management

createSubmission

Market Resolution

resolveMarket

Payout Claims

claimPayout

refundSingleSubmission

Fee Management

withdrawFees

View Functions

getMarketSubmissions

getUserSubmissions

getMarketDetails

getSubmissionDetails

Admin Functions

setFeeRecipient

pause

unpause

emergencyWithdraw

Utility Functions

levenshteinDistance

State Variables

marketCount

submissionCount

markets

submissions

pendingFees

feeRecipient

Build docs developers (and LLMs) love

REST API

Contract Methods

​Overview

​Constants

​Market Creation

​createMarket

​Submission Management

​createSubmission

​Market Resolution

​resolveMarket

​Payout Claims

​claimPayout

​refundSingleSubmission

​Fee Management

​withdrawFees

​View Functions

​getMarketSubmissions

​getUserSubmissions

​getMarketDetails

​getSubmissionDetails

​Admin Functions

​setFeeRecipient

​pause

​unpause

​emergencyWithdraw

​Utility Functions

​levenshteinDistance

​State Variables

​marketCount

​submissionCount

​markets

​submissions

​pendingFees

​feeRecipient

Build docs developers (and LLMs) love

Overview

Constants

Market Creation

createMarket

Submission Management

createSubmission

Market Resolution

resolveMarket

Payout Claims

claimPayout

refundSingleSubmission

Fee Management

withdrawFees

View Functions

getMarketSubmissions

getUserSubmissions

getMarketDetails

getSubmissionDetails

Admin Functions

setFeeRecipient

pause

unpause

emergencyWithdraw

Utility Functions

levenshteinDistance

State Variables

marketCount

submissionCount

markets

submissions

pendingFees

feeRecipient