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

import {
  buildAuthFailed,
  buildAuthRequest,
  buildAuthSuccess,
  buildDisconnectNotice,
  buildError,
  buildHeartbeat,
  buildHeartbeatAck,
  buildHello,
  buildHelloAck,
  buildPairConfirm,
  buildPairFailed,
  buildPairRequest,
  buildPairSuccess,
  buildRePairRequired,
  buildStatusUpdate,
  CodecError,
  decodeBuiltin,
  encodeBuiltin,
  encodeRewrittenRuleMessage,
  encodeRuleMessage,
  isBuiltinMessage,
  parseRewrittenRuleMessage,
  parseRuleMessage
} from "../src/index.js";

describe("Protocol Codec - encodeBuiltin / decodeBuiltin", () => {
  it("encodes and decodes a hello envelope", () => {
    const envelope = buildHello(
      {
        identifier: "client-a",
        hasSecret: true,
        hasKeyPair: true,
        publicKey: "pk-test",
        protocolVersion: "1"
      },
      { requestId: "req-001" }
    );

    const encoded = encodeBuiltin(envelope);
    expect(encoded.startsWith("builtin::")).toBe(true);

    const decoded = decodeBuiltin(encoded);
    expect(decoded.type).toBe("hello");
    expect(decoded.requestId).toBe("req-001");
    expect(decoded.payload).toMatchObject({
      identifier: "client-a",
      hasSecret: true,
      hasKeyPair: true,
      publicKey: "pk-test",
      protocolVersion: "1"
    });
  });

  it("encodes and decodes all builtin message types", () => {
    const testCases = [
      {
        builder: buildHelloAck,
        payload: { identifier: "client-a", nextAction: "pair_required" as const }
      },
      {
        builder: buildPairRequest,
        payload: {
          identifier: "client-a",
          expiresAt: 1_710_000_000,
          ttlSeconds: 300,
          adminNotification: "sent" as const,
          codeDelivery: "out_of_band" as const
        }
      },
      {
        builder: buildPairConfirm,
        payload: { identifier: "client-a", pairingCode: "ABCD-1234-XYZ" }
      },
      {
        builder: buildPairSuccess,
        payload: { identifier: "client-a", secret: "secret-xyz", pairedAt: 1_710_000_000 }
      },
      {
        builder: buildPairFailed,
        payload: { identifier: "client-a", reason: "expired" as const }
      },
      {
        builder: buildAuthRequest,
        payload: {
          identifier: "client-a",
          nonce: "RANDOM24CHARACTERSTRINGX",
          proofTimestamp: 1_710_000_000,
          signature: "sig-base64",
          publicKey: "pk-test"
        }
      },
      {
        builder: buildAuthSuccess,
        payload: { identifier: "client-a", authenticatedAt: 1_710_000_000, status: "online" as const }
      },
      {
        builder: buildAuthFailed,
        payload: { identifier: "client-a", reason: "invalid_signature" as const }
      },
      {
        builder: buildRePairRequired,
        payload: { identifier: "client-a", reason: "nonce_collision" as const }
      },
      {
        builder: buildHeartbeat,
        payload: { identifier: "client-a", status: "alive" as const }
      },
      {
        builder: buildHeartbeatAck,
        payload: { identifier: "client-a", status: "online" as const }
      },
      {
        builder: buildStatusUpdate,
        payload: { identifier: "client-a", status: "unstable" as const, reason: "heartbeat_timeout_7m" }
      },
      {
        builder: buildDisconnectNotice,
        payload: { identifier: "client-a", reason: "heartbeat_timeout_11m" }
      },
      {
        builder: buildError,
        payload: { code: "MALFORMED_MESSAGE" as const, message: "Invalid JSON" }
      }
    ];

    for (const { builder, payload } of testCases) {
      const envelope = builder(payload as never, { requestId: "test-req" });
      const encoded = encodeBuiltin(envelope);
      const decoded = decodeBuiltin(encoded);

      expect(decoded.type).toBe(envelope.type);
      expect(decoded.requestId).toBe("test-req");
      expect(decoded.payload).toMatchObject(payload);
    }
  });

  it("throws CodecError for malformed messages", () => {
    expect(() => decodeBuiltin("not-builtin::{")).toThrow(CodecError);
    expect(() => decodeBuiltin("builtin::not-json")).toThrow(CodecError);
    expect(() => decodeBuiltin("builtin::{}")).toThrow(CodecError); // missing type
    expect(() => decodeBuiltin("no-delimiter")).toThrow(CodecError);
    expect(() => decodeBuiltin("")).toThrow(CodecError);
  });

  it("throws CodecError for invalid envelope input", () => {
    expect(() => encodeBuiltin(null as never)).toThrow(CodecError);
    expect(() => encodeBuiltin({} as never)).toThrow(CodecError);
    expect(() => encodeBuiltin({ type: 123 } as never)).toThrow(CodecError);
  });
});

describe("Protocol Codec - Rule Message Parsing", () => {
  it("parses rule messages correctly", () => {
    const parsed = parseRuleMessage("chat_sync::{\"body\":\"hello\"}");
    expect(parsed.ruleIdentifier).toBe("chat_sync");
    expect(parsed.content).toBe('{"body":"hello"}');
  });

  it("handles content containing :: delimiters", () => {
    const parsed = parseRuleMessage("rule::a::b::c");
    expect(parsed.ruleIdentifier).toBe("rule");
    expect(parsed.content).toBe("a::b::c");
  });

  it("throws CodecError for invalid rule messages", () => {
    expect(() => parseRuleMessage("no-delimiter")).toThrow(CodecError);
    expect(() => parseRuleMessage(":")).toThrow(CodecError);
    expect(() => parseRuleMessage("")).toThrow(CodecError);
    expect(() => parseRuleMessage("::content")).toThrow(CodecError); // empty identifier
  });

  it("throws CodecError for reserved builtin identifier", () => {
    expect(() => parseRuleMessage("builtin::something")).toThrow(
      /reserved/
    );
  });

  it("throws CodecError for invalid rule identifier characters", () => {
    expect(() => parseRuleMessage("rule with spaces::content")).toThrow(CodecError);
    // Note: special chars in content are allowed - only the rule identifier is validated
    expect(() => parseRuleMessage("rule::with::special!::chars")).not.toThrow(); // content can contain special chars
  });

  it("isBuiltinMessage identifies builtin messages", () => {
    expect(isBuiltinMessage("builtin::{\"type\":\"hello\"}")).toBe(true);
    expect(isBuiltinMessage("rule::content")).toBe(false);
    expect(isBuiltinMessage("not-builtin::content")).toBe(false);
    expect(isBuiltinMessage("")).toBe(false);
  });
});

describe("Protocol Codec - Server Rewritten Messages", () => {
  it("parses rewritten messages with sender identifier", () => {
    const parsed = parseRewrittenRuleMessage("chat_sync::client-a::{\"body\":\"hello\"}");
    expect(parsed.ruleIdentifier).toBe("chat_sync");
    expect(parsed.senderIdentifier).toBe("client-a");
    expect(parsed.messageContent).toBe('{"body":"hello"}');
    expect(parsed.content).toBe("client-a::{\"body\":\"hello\"}");
  });

  it("handles complex content with multiple delimiters", () => {
    const parsed = parseRewrittenRuleMessage("rule::sender::a::b::c");
    expect(parsed.ruleIdentifier).toBe("rule");
    expect(parsed.senderIdentifier).toBe("sender");
    expect(parsed.messageContent).toBe("a::b::c");
  });

  it("throws CodecError for malformed rewritten messages", () => {
    expect(() => parseRewrittenRuleMessage("no-delimiters")).toThrow(CodecError);
    expect(() => parseRewrittenRuleMessage("rule::only-one")).toThrow(/sender/);
    expect(() => parseRewrittenRuleMessage("::sender::content")).toThrow(/Empty/);
    // Note: "rule:::content" has empty sender which is caught by "missing sender identifier delimiter" check
    expect(() => parseRewrittenRuleMessage("rule:::content")).toThrow(/sender/);
  });
});

describe("Protocol Codec - encodeRuleMessage", () => {
  it("encodes rule messages correctly", () => {
    const encoded = encodeRuleMessage("chat_sync", '{"body":"hello"}');
    expect(encoded).toBe('chat_sync::{"body":"hello"}');
  });

  it("throws CodecError for invalid rule identifiers", () => {
    expect(() => encodeRuleMessage("", "content")).toThrow(CodecError);
    expect(() => encodeRuleMessage("builtin", "content")).toThrow(/reserved/);
    expect(() => encodeRuleMessage("rule with spaces", "content")).toThrow(CodecError);
    expect(() => encodeRuleMessage("rule!", "content")).toThrow(CodecError);
  });

  it("throws CodecError for non-string content", () => {
    expect(() => encodeRuleMessage("rule", null as never)).toThrow(CodecError);
  });
});

describe("Protocol Codec - encodeRewrittenRuleMessage", () => {
  it("encodes rewritten messages correctly", () => {
    const encoded = encodeRewrittenRuleMessage("chat_sync", "client-a", '{"body":"hello"}');
    expect(encoded).toBe('chat_sync::client-a::{"body":"hello"}');
  });

  it("throws CodecError for reserved rule identifier", () => {
    expect(() => encodeRewrittenRuleMessage("builtin", "sender", "content")).toThrow(/reserved/);
  });

  it("throws CodecError for empty identifiers", () => {
    expect(() => encodeRewrittenRuleMessage("", "sender", "content")).toThrow(CodecError);
    expect(() => encodeRewrittenRuleMessage("rule", "", "content")).toThrow(CodecError);
  });
});