import { describe, it, expect } from "vitest";
import { Type } from "@alkdev/typebox";
import { FlowGraph } from "../../src/graph/construction.js";
import type { OperationSpec } from "../../src/graph/construction.js";
import { InvalidInputError, CycleError } from "../../src/error/index.js";

describe("FlowGraph.export", () => {
  it("returns graphology native JSON format for empty graph", () => {
    const fg = new FlowGraph();
    const data = fg.export();
    expect(data.options).toEqual({ type: "directed", multi: false, allowSelfLoops: false });
    expect(data.attributes).toEqual({});
    expect(data.nodes).toEqual([]);
    expect(data.edges).toEqual([]);
  });

  it("returns graphology native JSON format for operation graph", () => {
    const specs: OperationSpec[] = [
      { name: "extract", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ raw: Type.String() }), outputSchema: Type.Object({ text: Type.String() }) },
      { name: "classify", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ text: Type.String() }), outputSchema: Type.Object({ label: Type.String() }) },
    ];
    const graph = FlowGraph.fromSpecs(specs);
    const data = graph.export();
    expect(data.options.type).toBe("directed");
    expect(data.nodes.length).toBe(2);
    expect(data.edges.length).toBeGreaterThan(0);
  });
});

describe("FlowGraph.toJSON", () => {
  it("is an alias for export", () => {
    const fg = new FlowGraph();
    fg.addNode("a", { name: "a" } as never);
    const exported = fg.export();
    const jsoned = fg.toJSON();
    expect(jsoned).toEqual(exported);
  });
});

describe("FlowGraph.toString", () => {
  it("returns JSON.stringify of export()", () => {
    const fg = new FlowGraph();
    fg.addNode("a", { name: "a" } as never);
    expect(fg.toString()).toBe(JSON.stringify(fg.export()));
  });

  it("round-trips through JSON.parse", () => {
    const fg = new FlowGraph();
    fg.addNode("a", { name: "a" } as never);
    const parsed = JSON.parse(fg.toString());
    expect(parsed.options).toEqual({ type: "directed", multi: false, allowSelfLoops: false });
  });
});

describe("FlowGraph.fromJSON", () => {
  it("round-trips fromSpecs -> export -> fromJSON", () => {
    const specs: OperationSpec[] = [
      { name: "extract", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ raw: Type.String() }), outputSchema: Type.Object({ text: Type.String() }) },
      { name: "classify", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ text: Type.String() }), outputSchema: Type.Object({ label: Type.String() }) },
    ];
    const original = FlowGraph.fromSpecs(specs);
    const data = original.export();
    const restored = FlowGraph.fromJSON(data);
    expect(restored.order).toBe(original.order);
    expect(restored.size).toBe(original.size);
    for (const node of original.nodes()) {
      expect(restored.hasNode(node)).toBe(true);
      const origAttrs = original.getNodeAttributes(node as never) as Record<string, unknown>;
      const restAttrs = restored.getNodeAttributes(node as never) as Record<string, unknown>;
      expect(restAttrs.name).toBe(origAttrs.name);
      expect(restAttrs.namespace).toBe(origAttrs.namespace);
    }
    for (const edge of original.edges()) {
      const source = edge.split("->")[0]!;
      const target = edge.split("->")[1]!;
      expect(restored.hasEdge(source, target)).toBe(true);
    }
  });

  it("round-trips empty graph", () => {
    const fg = new FlowGraph();
    const data = fg.export();
    const restored = FlowGraph.fromJSON(data);
    expect(restored.order).toBe(0);
    expect(restored.size).toBe(0);
    expect(restored.export()).toEqual(data);
  });

  it("throws InvalidInputError on invalid input", () => {
    expect(() => FlowGraph.fromJSON({})).toThrow(InvalidInputError);
  });

  it("InvalidInputError contains errors array", () => {
    try {
      FlowGraph.fromJSON({});
      expect.unreachable("should throw");
    } catch (e) {
      expect(e).toBeInstanceOf(InvalidInputError);
      const err = e as InvalidInputError;
      expect(err.errors.length).toBeGreaterThan(0);
    }
  });

  it("throws InvalidInputError on missing nodes", () => {
    const bad = {
      options: { type: "directed", multi: false, allowSelfLoops: false },
      attributes: {},
      edges: [],
    };
    expect(() => FlowGraph.fromJSON(bad as never)).toThrow(InvalidInputError);
  });

  it("throws CycleError on cyclic input", () => {
    const cyclicData = {
      options: { type: "directed", multi: false, allowSelfLoops: false },
      attributes: {},
      nodes: [
        { key: "a", attributes: { requestId: "a", operationId: "op.a", status: "completed", input: {} } },
        { key: "b", attributes: { requestId: "b", operationId: "op.b", status: "completed", input: {} } },
      ],
      edges: [
        { key: "a->b", source: "a", target: "b", attributes: {} },
        { key: "b->a", source: "b", target: "a", attributes: {} },
      ],
    };
    expect(() => FlowGraph.fromJSON(cyclicData as never)).toThrow(CycleError);
  });

  it("CycleError contains cycle paths on cyclic input", () => {
    const cyclicData = {
      options: { type: "directed", multi: false, allowSelfLoops: false },
      attributes: {},
      nodes: [
        { key: "a", attributes: { requestId: "a", operationId: "op.a", status: "completed", input: {} } },
        { key: "b", attributes: { requestId: "b", operationId: "op.b", status: "completed", input: {} } },
      ],
      edges: [
        { key: "a->b", source: "a", target: "b", attributes: {} },
        { key: "b->a", source: "b", target: "a", attributes: {} },
      ],
    };
    try {
      FlowGraph.fromJSON(cyclicData as never);
      expect.unreachable("should throw");
    } catch (e) {
      expect(e).toBeInstanceOf(CycleError);
      const ce = e as CycleError;
      expect(ce.cycles.length).toBeGreaterThan(0);
    }
  });

  it("preserves node attributes through round-trip", () => {
    const specs: OperationSpec[] = [
      { name: "classify", namespace: "task", version: "2.0.0", type: "mutation", inputSchema: Type.Object({ text: Type.String() }), outputSchema: Type.Object({ label: Type.String() }), description: "Classifies text", tags: ["nlp"] },
    ];
    const original = FlowGraph.fromSpecs(specs);
    const data = original.export();
    const restored = FlowGraph.fromJSON(data);
    const origAttrs = original.getNodeAttributes("task.classify" as never) as Record<string, unknown>;
    const restAttrs = restored.getNodeAttributes("task.classify" as never) as Record<string, unknown>;
    expect(restAttrs.name).toBe(origAttrs.name);
    expect(restAttrs.namespace).toBe(origAttrs.namespace);
    expect(restAttrs.version).toBe(origAttrs.version);
    expect(restAttrs.type).toBe(origAttrs.type);
    expect(restAttrs.description).toBe(origAttrs.description);
    expect(restAttrs.tags).toEqual(origAttrs.tags);
  });

  it("preserves edge attributes through round-trip", () => {
    const specs: OperationSpec[] = [
      { name: "extract", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ raw: Type.String() }), outputSchema: Type.Object({ text: Type.String() }) },
      { name: "classify", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ text: Type.String() }), outputSchema: Type.Object({ label: Type.String() }) },
    ];
    const original = FlowGraph.fromSpecs(specs);
    const data = original.export();
    const restored = FlowGraph.fromJSON(data);
    const origEdgeAttrs = original.getEdgeAttributes("task.extract", "task.classify") as Record<string, unknown>;
    const restEdgeAttrs = restored.getEdgeAttributes("task.extract", "task.classify") as Record<string, unknown>;
    expect(restEdgeAttrs.edgeType).toBe(origEdgeAttrs.edgeType);
    expect(restEdgeAttrs.compatible).toBe(origEdgeAttrs.compatible);
  });

  it("double round-trip is lossless", () => {
    const specs: OperationSpec[] = [
      { name: "extract", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ raw: Type.String() }), outputSchema: Type.Object({ text: Type.String() }) },
      { name: "classify", namespace: "task", version: "1.0.0", type: "query", inputSchema: Type.Object({ text: Type.String() }), outputSchema: Type.Object({ label: Type.String() }) },
    ];
    const original = FlowGraph.fromSpecs(specs);
    const first = original.export();
    const restored1 = FlowGraph.fromJSON(first);
    const second = restored1.export();
    const restored2 = FlowGraph.fromJSON(second);
    const third = restored2.export();
    expect(third).toEqual(first);
    expect(third).toEqual(second);
  });

  it("accepts valid call graph serialized data", () => {
    const callData = {
      options: { type: "directed", multi: false, allowSelfLoops: false },
      attributes: {},
      nodes: [
        {
          key: "req_1",
          attributes: {
            requestId: "req_1",
            operationId: "task.classify",
            status: "completed",
            input: { text: "hello" },
            output: { label: "greeting" },
          },
        },
      ],
      edges: [],
    };
    const fg = FlowGraph.fromJSON(callData as never);
    expect(fg.order).toBe(1);
    expect(fg.hasNode("req_1")).toBe(true);
  });

  it("throws InvalidInputError for invalid node attributes", () => {
    const bad = {
      options: { type: "directed", multi: false, allowSelfLoops: false },
      attributes: {},
      nodes: [
        { key: "a", attributes: { invalid: true } },
      ],
      edges: [],
    };
    expect(() => FlowGraph.fromJSON(bad as never)).toThrow(InvalidInputError);
  });
});