From 9175c82f98210736ab555413c5924c089d7809ef Mon Sep 17 00:00:00 2001 From: Phan Huy Tran Date: Wed, 21 May 2025 08:58:25 +0200 Subject: [PATCH] feat: implement dice game api --- .../de/szut/casino/dice/DiceController.java | 44 ++++++++++++ .../java/de/szut/casino/dice/DiceDto.java | 25 +++++++ .../java/de/szut/casino/dice/DiceResult.java | 39 +++++++++++ .../java/de/szut/casino/dice/DiceService.java | 68 +++++++++++++++++++ 4 files changed, 176 insertions(+) create mode 100644 backend/src/main/java/de/szut/casino/dice/DiceController.java create mode 100644 backend/src/main/java/de/szut/casino/dice/DiceDto.java create mode 100644 backend/src/main/java/de/szut/casino/dice/DiceResult.java create mode 100644 backend/src/main/java/de/szut/casino/dice/DiceService.java diff --git a/backend/src/main/java/de/szut/casino/dice/DiceController.java b/backend/src/main/java/de/szut/casino/dice/DiceController.java new file mode 100644 index 0000000..949a002 --- /dev/null +++ b/backend/src/main/java/de/szut/casino/dice/DiceController.java @@ -0,0 +1,44 @@ +package de.szut.casino.dice; + +import de.szut.casino.exceptionHandling.exceptions.InsufficientFundsException; +import de.szut.casino.exceptionHandling.exceptions.UserNotFoundException; +import de.szut.casino.shared.service.BalanceService; +import de.szut.casino.user.UserEntity; +import de.szut.casino.user.UserService; +import jakarta.validation.Valid; +import org.springframework.http.ResponseEntity; +import org.springframework.web.bind.annotation.PostMapping; +import org.springframework.web.bind.annotation.RequestBody; +import org.springframework.web.bind.annotation.RestController; + +import java.util.Optional; + +@RestController +public class DiceController { + private final UserService userService; + private final BalanceService balanceService; + private final DiceService diceService; + + public DiceController(UserService userService, BalanceService balanceService, DiceService diceService) { + this.userService = userService; + this.balanceService = balanceService; + this.diceService = diceService; + } + + @PostMapping("/dice") + public ResponseEntity rollDice(@RequestBody @Valid DiceDto diceDto) { + Optional optionalUser = userService.getCurrentUser(); + + if (optionalUser.isEmpty()) { + throw new UserNotFoundException(); + } + + UserEntity user = optionalUser.get(); + + if (!this.balanceService.hasFunds(user, diceDto)) { + throw new InsufficientFundsException(); + } + + return ResponseEntity.ok(diceService.play(user, diceDto)); + } +} diff --git a/backend/src/main/java/de/szut/casino/dice/DiceDto.java b/backend/src/main/java/de/szut/casino/dice/DiceDto.java new file mode 100644 index 0000000..ccec485 --- /dev/null +++ b/backend/src/main/java/de/szut/casino/dice/DiceDto.java @@ -0,0 +1,25 @@ +package de.szut.casino.dice; + +import de.szut.casino.shared.dto.BetDto; +import jakarta.validation.constraints.DecimalMin; +import jakarta.validation.constraints.NotNull; +import lombok.Getter; +import lombok.Setter; + +import java.math.BigDecimal; + +@Getter +@Setter +public class DiceDto extends BetDto { + private boolean rollOver; + + @NotNull + @DecimalMin(value = "1.00") + private BigDecimal targetValue; + + public DiceDto(BigDecimal betAmount, boolean rollOver, BigDecimal targetValue) { + super(betAmount); + this.rollOver = rollOver; + this.targetValue = targetValue; + } +} diff --git a/backend/src/main/java/de/szut/casino/dice/DiceResult.java b/backend/src/main/java/de/szut/casino/dice/DiceResult.java new file mode 100644 index 0000000..5a1c797 --- /dev/null +++ b/backend/src/main/java/de/szut/casino/dice/DiceResult.java @@ -0,0 +1,39 @@ +package de.szut.casino.dice; + +import java.math.BigDecimal; + +public class DiceResult { + private boolean win; + private BigDecimal payout; + private BigDecimal rolledValue; + + public DiceResult(boolean win, BigDecimal payout, BigDecimal rolledValue) { + this.win = win; + this.payout = payout; + this.rolledValue = rolledValue; + } + + public boolean isWin() { + return win; + } + + public void setWin(boolean win) { + this.win = win; + } + + public BigDecimal getPayout() { + return payout; + } + + public void setPayout(BigDecimal payout) { + this.payout = payout; + } + + public BigDecimal getRolledValue() { + return rolledValue; + } + + public void setRolledValue(BigDecimal rolledValue) { + this.rolledValue = rolledValue; + } +} diff --git a/backend/src/main/java/de/szut/casino/dice/DiceService.java b/backend/src/main/java/de/szut/casino/dice/DiceService.java new file mode 100644 index 0000000..71e4584 --- /dev/null +++ b/backend/src/main/java/de/szut/casino/dice/DiceService.java @@ -0,0 +1,68 @@ +package de.szut.casino.dice; + +import de.szut.casino.shared.service.BalanceService; +import de.szut.casino.user.UserEntity; +import org.springframework.stereotype.Service; + +import java.math.BigDecimal; +import java.math.RoundingMode; +import java.util.Random; + +@Service +public class DiceService { + private static final int MAX_DICE_VALUE = 100; + private final Random random = new Random(); + private final BalanceService balanceService; + + public DiceService(BalanceService balanceService) { + this.balanceService = balanceService; + } + + public DiceResult play(UserEntity user, DiceDto diceDto) { + balanceService.subtractFunds(user, diceDto.getBetAmount()); + + int rolledValue = random.nextInt(MAX_DICE_VALUE) + 1; + BigDecimal rolledValueDecimal = BigDecimal.valueOf(rolledValue); + + BigDecimal targetValue = diceDto.getTargetValue(); + boolean isRollOver = diceDto.isRollOver(); + + boolean winConditionMet = isWinConditionMet(rolledValueDecimal, targetValue, isRollOver); + + if (!winConditionMet) { + return new DiceResult(false, BigDecimal.ZERO, rolledValueDecimal); + } + + BigDecimal winChance = calculateWinChance(targetValue, isRollOver); + BigDecimal multiplier = calculateMultiplier(winChance); + + BigDecimal payout = diceDto.getBetAmount().multiply(multiplier); + balanceService.addFunds(user, payout); + + return new DiceResult(true, payout, rolledValueDecimal); + } + + private boolean isWinConditionMet(BigDecimal rolledValue, BigDecimal targetValue, boolean isRollOver) { + if (isRollOver) { + return rolledValue.compareTo(targetValue) > 0; + } + + return rolledValue.compareTo(targetValue) < 0; + } + + private BigDecimal calculateWinChance(BigDecimal targetValue, boolean isRollOver) { + if (isRollOver) { + return BigDecimal.valueOf(MAX_DICE_VALUE).subtract(targetValue); + } + + return targetValue.subtract(BigDecimal.ONE); + } + + private BigDecimal calculateMultiplier(BigDecimal winChance) { + if (winChance.compareTo(BigDecimal.ZERO) > 0) { + return BigDecimal.valueOf(MAX_DICE_VALUE - 1).divide(winChance, 4, RoundingMode.HALF_UP); + } + + return BigDecimal.ZERO; + } +}