import { describe, it, expect } from "vitest";

/**
 * Tests pour les erreurs, edge cases et scénarios dégradés
 */
describe("error handling & edge cases", () => {
  describe("database error handling", () => {
    it("gère les erreurs de connexion DB", () => {
      const handleDBError = (
        error: any,
      ): { statusCode: number; message: string } => {
        if (error.code === "ECONNREFUSED") {
          return { statusCode: 503, message: "Service unavailable" };
        }
        if (error.code === "PROTOCOL_CONNECTION_LOST") {
          return { statusCode: 503, message: "Connection lost" };
        }
        return { statusCode: 500, message: "Internal server error" };
      };

      expect(handleDBError({ code: "ECONNREFUSED" })).toEqual({
        statusCode: 503,
        message: "Service unavailable",
      });
      expect(handleDBError({ code: "PROTOCOL_CONNECTION_LOST" })).toEqual({
        statusCode: 503,
        message: "Connection lost",
      });
    });

    it("gère les timeouts de requête DB", () => {
      const isTimeoutError = (error: any): boolean => {
        return (
          error.code === "ETIMEDOUT" ||
          error.code === "PROTOCOL_SEQUENCE_TIMEOUT" ||
          error.message?.includes("timeout")
        );
      };

      expect(isTimeoutError({ code: "ETIMEDOUT" })).toBe(true);
      expect(isTimeoutError({ code: "PROTOCOL_SEQUENCE_TIMEOUT" })).toBe(true);
      expect(isTimeoutError({ message: "Query timeout" })).toBe(true);
      expect(isTimeoutError({ code: "ERR_UNKNOWN", message: "" })).toBe(false);
    });

    it("gère les contraintes d'intégrité DB", () => {
      const handleConstraintError = (
        error: any,
      ): { statusCode: number; message: string } => {
        if (error.code === "ER_DUP_ENTRY") {
          return { statusCode: 409, message: "Resource already exists" };
        }
        if (error.code === "ER_NO_REFERENCED_ROW_2") {
          return { statusCode: 400, message: "Invalid reference" };
        }
        if (error.code === "ER_ROW_IS_REFERENCED_2") {
          return { statusCode: 409, message: "Cannot delete: referenced" };
        }
        return { statusCode: 500, message: "Constraint error" };
      };

      expect(handleConstraintError({ code: "ER_DUP_ENTRY" })).toEqual({
        statusCode: 409,
        message: "Resource already exists",
      });
      expect(handleConstraintError({ code: "ER_NO_REFERENCED_ROW_2" })).toEqual(
        {
          statusCode: 400,
          message: "Invalid reference",
        },
      );
    });
  });

  describe("validation errors", () => {
    it("rejette les valeurs null/undefined", () => {
      const validateRequired = (value: any): boolean => {
        return value !== null && value !== undefined && value !== "";
      };

      expect(validateRequired("valid")).toBe(true);
      expect(validateRequired(null)).toBe(false);
      expect(validateRequired(undefined)).toBe(false);
      expect(validateRequired("")).toBe(false);
    });

    it("valide les longueurs min/max", () => {
      const validateLength = (
        value: string,
        min: number,
        max: number,
      ): boolean => {
        return value.length >= min && value.length <= max;
      };

      expect(validateLength("hello", 3, 10)).toBe(true);
      expect(validateLength("hi", 3, 10)).toBe(false);
      expect(validateLength("this is way too long", 3, 10)).toBe(false);
    });

    it("valide les nombres min/max", () => {
      const validateRange = (
        value: number,
        min: number,
        max: number,
      ): boolean => {
        return value >= min && value <= max;
      };

      expect(validateRange(50, 0, 100)).toBe(true);
      expect(validateRange(-1, 0, 100)).toBe(false);
      expect(validateRange(101, 0, 100)).toBe(false);
    });

    it("valide les formats d'enum", () => {
      const VALID_DIFFICULTIES = ["easy", "medium", "hard"] as const;

      const validateDifficulty = (value: any): boolean => {
        return VALID_DIFFICULTIES.includes(value);
      };

      expect(validateDifficulty("easy")).toBe(true);
      expect(validateDifficulty("hard")).toBe(true);
      expect(validateDifficulty("impossible")).toBe(false);
      expect(validateDifficulty(123)).toBe(false);
    });

    it("gère les valeurs décimales invalides", () => {
      const validateDecimal = (value: any, places: number): boolean => {
        if (typeof value !== "number") return false;
        const str = value.toString();
        const decimals = str.split(".")[1];
        return !decimals || decimals.length <= places;
      };

      expect(validateDecimal(19.99, 2)).toBe(true);
      expect(validateDecimal(19.999, 2)).toBe(false);
      expect(validateDecimal("19.99", 2)).toBe(false);
    });
  });

  describe("input sanitization", () => {
    it("supprime les espaces blancs", () => {
      const trim = (value: string): string => value.trim();

      expect(trim("  hello  ")).toBe("hello");
      expect(trim("\nhello\t")).toBe("hello");
    });

    it("normalise la casse", () => {
      const normalizeEmail = (email: string): string =>
        email.toLowerCase().trim();

      expect(normalizeEmail("  USER@EXAMPLE.COM  ")).toBe("user@example.com");
      expect(normalizeEmail("Test@Example.Com")).toBe("test@example.com");
    });

    it("filtre les caractères non autorisés", () => {
      const sanitizeUsername = (username: string): string => {
        return username.replace(/[^a-zA-Z0-9_\-\.]/g, "");
      };

      expect(sanitizeUsername("User@123!")).toBe("User123");
      expect(sanitizeUsername("Alice-Bob_123")).toBe("Alice-Bob_123");
    });

    it("gère les valeurs vides après normalisation", () => {
      const normalizeAndValidate = (value: string): boolean => {
        const normalized = value.trim();
        return normalized.length > 0;
      };

      expect(normalizeAndValidate("  ")).toBe(false);
      expect(normalizeAndValidate("valid")).toBe(true);
      expect(normalizeAndValidate("\t\n")).toBe(false);
    });
  });

  describe("rate limiting & throttling", () => {
    it("compte les tentatives échouées", () => {
      class LoginTracker {
        private attempts: Map<string, { count: number; timestamp: number }> =
          new Map();

        recordFailure(email: string): number {
          const entry = this.attempts.get(email) || {
            count: 0,
            timestamp: Date.now(),
          };
          entry.count++;
          this.attempts.set(email, entry);
          return entry.count;
        }

        reset(email: string): void {
          this.attempts.delete(email);
        }
      }

      const tracker = new LoginTracker();
      expect(tracker.recordFailure("user@example.com")).toBe(1);
      expect(tracker.recordFailure("user@example.com")).toBe(2);
      expect(tracker.recordFailure("user@example.com")).toBe(3);
    });

    it("réinitialise le compteur après la fenêtre d'expiration", () => {
      const isRateLimited = (
        attempts: number,
        maxAttempts: number,
        lastAttemptTime: number,
        windowMs: number,
        now: number,
      ): boolean => {
        if (now - lastAttemptTime > windowMs) {
          return false; // Fenêtre expirée, pas de rate limit
        }
        return attempts >= maxAttempts;
      };

      const now = Date.now();
      const windowMs = 60000; // 1 minute

      expect(isRateLimited(5, 5, now, windowMs, now)).toBe(true);
      expect(isRateLimited(5, 5, now - windowMs - 1000, windowMs, now)).toBe(
        false,
      );
    });

    it("rejette les requêtes après le dépassement de limite", () => {
      class RateLimiter {
        private limits: Map<string, number> = new Map();
        private maxRequests: number;
        private windowMs: number;

        constructor(maxRequests: number, windowMs: number) {
          this.maxRequests = maxRequests;
          this.windowMs = windowMs;
        }

        isAllowed(key: string): boolean {
          const now = Date.now();
          const count = this.limits.get(key) || 0;

          if (count >= this.maxRequests) {
            return false;
          }

          this.limits.set(key, count + 1);

          // Simple cleanup (en vrai, il faudrait un TTL)
          setTimeout(() => this.limits.delete(key), this.windowMs);

          return true;
        }
      }

      const limiter = new RateLimiter(3, 1000);
      expect(limiter.isAllowed("user1")).toBe(true);
      expect(limiter.isAllowed("user1")).toBe(true);
      expect(limiter.isAllowed("user1")).toBe(true);
      expect(limiter.isAllowed("user1")).toBe(false);
    });
  });

  describe("concurrent request handling", () => {
    it("gère les condition races sur les updates", () => {
      interface User {
        id: number;
        balance: number;
        version: number;
      }

      const updateBalance = (
        user: User,
        amount: number,
        expectedVersion: number,
      ): User | null => {
        if (user.version !== expectedVersion) {
          return null; // Conflit de version
        }
        return {
          ...user,
          balance: user.balance + amount,
          version: user.version + 1,
        };
      };

      const user: User = { id: 1, balance: 100, version: 1 };

      // Update concurrence 1: succès
      const updated1 = updateBalance(user, 50, 1);
      expect(updated1).not.toBeNull();
      expect(updated1?.balance).toBe(150);
      expect(updated1?.version).toBe(2);

      // Simuler race condition avec version stale
      const staleUser: User = { id: 1, balance: 100, version: 1 };
      const raceUpdate = updateBalance(staleUser, 50, 2); // Version incorrecte
      expect(raceUpdate).toBeNull();
    });

    it("gère les deadlocks avec timeout", async () => {
      const executeWithTimeout = async (
        promise: Promise<any>,
        timeoutMs: number,
      ): Promise<any> => {
        const timeoutPromise = new Promise((_, reject) => {
          setTimeout(() => reject(new Error("Deadlock timeout")), timeoutMs);
        });
        return Promise.race([promise, timeoutPromise]);
      };

      const slowQuery = new Promise((resolve) => {
        setTimeout(() => resolve("done"), 2000);
      });

      // Timeout de 1 seconde, query prend 2 secondes
      await expect(executeWithTimeout(slowQuery, 1000)).rejects.toThrow(
        "Deadlock timeout",
      );
    });
  });

  describe("resource limits", () => {
    it("limite la taille des uploads", () => {
      const MAX_FILE_SIZE = 10 * 1024 * 1024; // 10 MB

      const isValidFileSize = (sizeInBytes: number): boolean => {
        return sizeInBytes > 0 && sizeInBytes <= MAX_FILE_SIZE;
      };

      expect(isValidFileSize(1024)).toBe(true);
      expect(isValidFileSize(MAX_FILE_SIZE)).toBe(true);
      expect(isValidFileSize(MAX_FILE_SIZE + 1)).toBe(false);
      expect(isValidFileSize(0)).toBe(false);
    });

    it("limite le nombre de résultats paginés", () => {
      const validatePaginationParams = (
        page: number,
        limit: number,
      ): boolean => {
        const MAX_LIMIT = 100;
        return page >= 1 && limit >= 1 && limit <= MAX_LIMIT;
      };

      expect(validatePaginationParams(1, 50)).toBe(true);
      expect(validatePaginationParams(1, 100)).toBe(true);
      expect(validatePaginationParams(1, 101)).toBe(false);
      expect(validatePaginationParams(0, 50)).toBe(false);
    });
  });

  describe("state consistency", () => {
    it("gère les transitions d'état invalides", () => {
      type GameState = "idle" | "playing" | "paused" | "finished";

      const validTransitions: Record<GameState, GameState[]> = {
        idle: ["playing"],
        playing: ["paused", "finished"],
        paused: ["playing", "finished"],
        finished: ["idle"],
      };

      const canTransition = (from: GameState, to: GameState): boolean => {
        return validTransitions[from].includes(to);
      };

      expect(canTransition("idle", "playing")).toBe(true);
      expect(canTransition("idle", "finished")).toBe(false);
      expect(canTransition("playing", "paused")).toBe(true);
      expect(canTransition("paused", "idle")).toBe(false);
    });

    it("gère les commandes idempotentes", () => {
      const processCommand = (
        commandId: string,
        processedCommands: Set<string>,
      ): boolean => {
        if (processedCommands.has(commandId)) {
          return true; // Déjà traité, idempotent
        }
        processedCommands.add(commandId);
        return true;
      };

      const processed = new Set<string>();
      expect(processCommand("cmd1", processed)).toBe(true);
      expect(processCommand("cmd1", processed)).toBe(true); // Pas rejouée
      expect(processed.size).toBe(1); // Exécutée une seule fois
    });
  });
});