Prediction Market Smart Contract

predict/.gitignore

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+
+**/settings/Mainnet.toml
+**/settings/Testnet.toml
+.requirements/
+history.txt

predict/.vscode/settings.json

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+
+{
+    "deno.enable": true,
+    "files.eol": "\n"
+}

predict/.vscode/tasks.json

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+
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "check contracts",
+            "group": "test",
+            "type": "shell",
+            "command": "clarinet check"
+        },
+        {
+            "label": "test contracts",
+            "group": "test",
+            "type": "shell",
+            "command": "clarinet test"
+        }
+    ]
+}

predict/Clarinet.toml

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+[project]
+name = "predict"
+authors = []
+description = ""
+telemetry = true
+requirements = []
+cache_dir = "/home/runner/hadassah/High-level/predict/./.requirements"
+boot_contracts = ["pox", "costs-v2", "bns"]
+[contracts.prediction]
+path = "contracts/prediction.clar"
+
+[repl]
+costs_version = 2
+parser_version = 2
+
+[repl.analysis]
+passes = ["check_checker"]
+
+[repl.analysis.check_checker]
+strict = false
+trusted_sender = false
+trusted_caller = false
+callee_filter = false

predict/README.md

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+# Prediction Market Smart Contract
+
+## ABOUT
+
+This smart contract implements a decentralized prediction market on the Stacks blockchain. Users can create markets, place bets, resolve markets, and claim payouts. The contract is designed to be fair, transparent, and efficient.
+
+## Features
+
+- Create prediction markets
+- Place bets on market outcomes (Yes/No)
+- Resolve markets
+- Claim payouts for winning bets
+- Fee system for contract sustainability
+
+## Contract Details
+
+- *Language*: Clarity
+- *Blockchain*: Stacks
+- *Minimum Bet*: 1 STX (1,000,000 microSTX)
+- *Fee*: 0.5% of winnings
+
+## Functions
+
+### Public Functions
+
+1. create-market: Create a new prediction market
+2. place-bet: Place a bet on a market outcome
+3. resolve-market: Resolve a market (only by market creator)
+4. claim-payout: Claim winnings from a resolved market
+5. withdraw-fees: Withdraw accumulated fees (only by contract owner)
+
+### Read-only Functions
+
+1. get-market-info: Get information about a specific market
+2. get-user-bets: Get a user's bets for a specific market
+3. get-accumulated-fees: Get the total accumulated fees
+
+## Usage
+
+### Creating a Market
+
+To create a new prediction market:
+
+clarity
+(contract-call? .prediction-market create-market "Will it rain tomorrow?" u12345678)
+
+
+- Parameters:
+  - Description (string-utf8 256): Market question or description
+  - Resolution timestamp (uint): Block height when the market will be resolved
+
+### Placing a Bet
+
+To place a bet on a market outcome:
+
+clarity
+(contract-call? .prediction-market place-bet u1 true u1000000)
+
+
+- Parameters:
+  - Market ID (uint): The ID of the market
+  - Bet outcome (bool): true for "Yes", false for "No"
+  - Amount (uint): Bet amount in microSTX (minimum 1,000,000)
+
+### Resolving a Market
+
+To resolve a market (only by the market creator):
+
+clarity
+(contract-call? .prediction-market resolve-market u1 true)
+
+
+- Parameters:
+  - Market ID (uint): The ID of the market
+  - Outcome (bool): true for "Yes", false for "No"
+
+### Claiming a Payout
+
+To claim a payout for a winning bet:
+
+clarity
+(contract-call? .prediction-market claim-payout u1)
+
+
+- Parameters:
+  - Market ID (uint): The ID of the resolved market
+
+### Withdrawing Fees
+
+To withdraw accumulated fees (only by contract owner):
+
+clarity
+(contract-call? .prediction-market withdraw-fees)
+
+
+## Error Codes
+
+- ERR-UNAUTHORIZED (u100): Unauthorized action
+- ERR-ALREADY-INITIALIZED (u101): Market already initialized
+- ERR-NOT-INITIALIZED (u102): Market not initialized
+- ERR-INVALID-BET (u103): Invalid bet parameters
+- ERR-MARKET-CLOSED (u104): Market is closed for betting
+- ERR-ALREADY-RESOLVED (u105): Market already resolved
+- ERR-INSUFFICIENT-BALANCE (u106): Insufficient balance for bet
+- ERR-NO-PAYOUT (u107): No payout available
+
+## Security Considerations
+
+- Only the market creator can resolve a market
+- Markets can only be resolved after the specified resolution timestamp
+- Minimum bet amount and description length to prevent spam
+- Fee system to incentivize contract maintenance and prevent abuse
+
+## Limitations
+
+- Binary outcomes only (Yes/No)
+- No partial withdrawals or bet cancellations
+- Fixed fee percentage
+
+## Future Improvements
+
+- Multiple outcome support
+- Dynamic fee adjustment
+- Partial bet withdrawal
+- Integration with external data sources for automated resolution
+
+## AUTHOR
+ESTHER OJO

predict/contracts/prediction.clar

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+;; Prediction Market Smart Contract
+
+;; Constants
+(define-constant CONTRACT-OWNER tx-sender)
+(define-constant ERR-UNAUTHORIZED (err u100))
+(define-constant ERR-ALREADY-INITIALIZED (err u101))
+(define-constant ERR-NOT-INITIALIZED (err u102))
+(define-constant ERR-INVALID-BET (err u103))
+(define-constant ERR-MARKET-CLOSED (err u104))
+(define-constant ERR-ALREADY-RESOLVED (err u105))
+(define-constant ERR-INSUFFICIENT-BALANCE (err u106))
+(define-constant ERR-NO-PAYOUT (err u107))
+(define-constant MINIMUM-BET-AMOUNT u1000000) ;; 1 STX
+(define-constant FEE-PERCENTAGE u5) ;; 0.5%
+(define-constant MIN-DESCRIPTION-LENGTH u10)
+
+;; Data Variables
+(define-data-var market-state (string-ascii 20) "uninitialized")
+(define-data-var market-id uint u0)
+(define-data-var market-creator principal CONTRACT-OWNER)
+(define-data-var market-description (string-utf8 256) u"")
+(define-data-var resolution-timestamp uint u0)
+(define-data-var total-yes-amount uint u0)
+(define-data-var total-no-amount uint u0)
+(define-data-var market-outcome (optional bool) none)
+(define-data-var accumulated-fees uint u0)
+
+;; Data Maps
+(define-map markets uint {
+  creator: principal,
+  description: (string-utf8 256),
+  resolution-timestamp: uint,
+  total-yes-amount: uint,
+  total-no-amount: uint,
+  outcome: (optional bool),
+  state: (string-ascii 20)
+})
+
+(define-map user-bets { market-id: uint, user: principal } { yes-amount: uint, no-amount: uint })
+
+;; Private Functions
+(define-private (is-valid-description (description (string-utf8 256)))
+  (>= (len description) MIN-DESCRIPTION-LENGTH)
+)
+
+(define-private (is-market-open (market-id-param uint))
+  (let ((market (unwrap! (map-get? markets market-id-param) false)))
+    (and 
+      (is-eq (get state market) "active")
+      (< block-height (get resolution-timestamp market))
+    )
+  )
+)
+
+(define-private (calculate-payout (bet-amount uint) (winning-pool uint) (losing-pool uint))
+  (let (
+    (total-pool (+ winning-pool losing-pool))
+    (payout-ratio (/ (* bet-amount u100000000) winning-pool))
+    (gross-payout (/ (* total-pool payout-ratio) u100000000))
+    (fee (/ (* gross-payout FEE-PERCENTAGE) u1000))
+  )
+    (- gross-payout fee)
+  )
+)
+
+(define-private (transfer-token (amount uint) (sender principal) (recipient principal))
+  (begin
+    (try! (stx-transfer? amount sender recipient))
+    (ok true)
+  )
+)
+
+;; Public Functions
+(define-public (create-market (description (string-utf8 256)) (resolution-time uint))
+  (let ((new-market-id (+ (var-get market-id) u1)))
+    (asserts! (> resolution-time block-height) ERR-INVALID-BET)
+    (asserts! (is-valid-description description) ERR-INVALID-BET)
+    (map-set markets new-market-id {
+      creator: tx-sender,
+      description: description,
+      resolution-timestamp: resolution-time,
+      total-yes-amount: u0,
+      total-no-amount: u0,
+      outcome: none,
+      state: "active"
+    })
+    (var-set market-id new-market-id)
+    (ok new-market-id)
+  )
+)
+
+(define-public (place-bet (market-id-param uint) (bet-yes bool) (amount uint))
+  (let (
+    (market (unwrap! (map-get? markets market-id-param) ERR-NOT-INITIALIZED))
+    (user-bet (default-to { yes-amount: u0, no-amount: u0 } 
+               (map-get? user-bets { market-id: market-id-param, user: tx-sender })))
+    (user-balance (stx-get-balance tx-sender))
+  )
+    (asserts! (is-market-open market-id-param) ERR-MARKET-CLOSED)
+    (asserts! (>= amount MINIMUM-BET-AMOUNT) ERR-INVALID-BET)
+    (asserts! (>= user-balance amount) ERR-INSUFFICIENT-BALANCE)
+
+    (if bet-yes
+      (map-set markets market-id-param 
+        (merge market { total-yes-amount: (+ (get total-yes-amount market) amount) }))
+      (map-set markets market-id-param 
+        (merge market { total-no-amount: (+ (get total-no-amount market) amount) }))
+    )
+
+    (map-set user-bets { market-id: market-id-param, user: tx-sender } 
+      (merge user-bet { 
+        yes-amount: (if bet-yes (+ (get yes-amount user-bet) amount) (get yes-amount user-bet)),
+        no-amount: (if bet-yes (get no-amount user-bet) (+ (get no-amount user-bet) amount))
+      })
+    )
+
+    (try! (transfer-token amount tx-sender (as-contract tx-sender)))
+    (ok true)
+  )
+)
+
+(define-public (resolve-market (market-id-param uint) (outcome bool))
+  (let ((market (unwrap! (map-get? markets market-id-param) ERR-NOT-INITIALIZED)))
+    (asserts! (is-eq tx-sender (get creator market)) ERR-UNAUTHORIZED)
+    (asserts! (is-eq (get state market) "active") ERR-ALREADY-RESOLVED)
+    (asserts! (>= block-height (get resolution-timestamp market)) ERR-MARKET-CLOSED)
+
+    (map-set markets market-id-param 
+      (merge market { 
+        outcome: (some outcome),
+        state: "resolved"
+      })
+    )
+    (ok true)
+  )
+)
+
+(define-public (claim-payout (market-id-param uint))
+  (let (
+    (market (unwrap! (map-get? markets market-id-param) ERR-NOT-INITIALIZED))
+    (user-bet (unwrap! (map-get? user-bets { market-id: market-id-param, user: tx-sender }) ERR-INVALID-BET))
+    (outcome (unwrap! (get outcome market) ERR-NOT-INITIALIZED))
+  )
+    (asserts! (is-eq (get state market) "resolved") ERR-NOT-INITIALIZED)
+
+    (let (
+      (winning-amount (if outcome (get yes-amount user-bet) (get no-amount user-bet)))
+      (winning-pool (if outcome (get total-yes-amount market) (get total-no-amount market)))
+      (losing-pool (if outcome (get total-no-amount market) (get total-yes-amount market)))
+    )
+      (asserts! (> winning-amount u0) ERR-NO-PAYOUT)
+
+      (let (
+        (payout (calculate-payout winning-amount winning-pool losing-pool))
+      )
+        (map-delete user-bets { market-id: market-id-param, user: tx-sender })
+        (var-set accumulated-fees (+ (var-get accumulated-fees) (- (+ winning-pool losing-pool) payout)))
+        (try! (as-contract (transfer-token payout tx-sender tx-sender)))
+        (ok payout)
+      )
+    )
+  )
+)
+
+(define-public (withdraw-fees)
+  (begin
+    (asserts! (is-eq tx-sender CONTRACT-OWNER) ERR-UNAUTHORIZED)
+    (let ((fees (var-get accumulated-fees)))
+      (var-set accumulated-fees u0)
+      (try! (as-contract (transfer-token fees tx-sender CONTRACT-OWNER)))
+      (ok fees)
+    )
+  )
+)
+
+;; Read-only Functions
+(define-read-only (get-market-info (market-id-param uint))
+  (ok (unwrap! (map-get? markets market-id-param) ERR-NOT-INITIALIZED))
+)
+
+(define-read-only (get-user-bets (market-id-param uint) (user principal))
+  (ok (default-to { yes-amount: u0, no-amount: u0 } 
+      (map-get? user-bets { market-id: market-id-param, user: user })))
+)
+
+(define-read-only (get-accumulated-fees)
+  (ok (var-get accumulated-fees))
+)