import { describe, it, expect } from "vitest";
import { Type } from "@alkdev/typebox";
import { h, createHostRoot } from "@alkdev/ujsx";
import { Operation, Sequential, Parallel, Conditional } from "../../src/component/index.js";
import { validatePreconditions, validateTemplate } from "../../src/analysis/workflow.js";
import { FlowGraph } from "../../src/graph/construction.js";
import type { OperationNodeAttrs, OperationEdgeAttrs } from "../../src/schema/index.js";

type OpGraph = FlowGraph<typeof import("../../src/schema/node.js").OperationNodeAttrs, typeof import("../../src/schema/edge.js").OperationEdgeAttrs>;

function createOperationGraph(
  specs: Array<{
    name: string;
    namespace?: string;
    inputSchema?: Record<string, unknown>;
    outputSchema?: Record<string, unknown>;
  }>,
): OpGraph {
  const graph = new FlowGraph() as OpGraph;
  for (const spec of specs) {
    const ns = spec.namespace ?? "test";
    const key = `${ns}.${spec.name}`;
    graph.addNode(key, {
      name: spec.name,
      namespace: ns,
      version: "1.0.0",
      type: "query",
      inputSchema: spec.inputSchema ?? Type.Object({}),
      outputSchema: spec.outputSchema ?? Type.Object({}),
    } as OperationNodeAttrs);
  }
  return graph;
}

function createOperationGraphWithEdges(
  specs: Array<{
    name: string;
    namespace?: string;
    inputSchema?: Record<string, unknown>;
    outputSchema?: Record<string, unknown>;
  }>,
  edges?: Array<{ source: string; target: string; compatible: boolean; mismatches?: Array<{ path: string; expected: string; actual: string }> }>,
): OpGraph {
  const graph = createOperationGraph(specs);
  if (edges) {
    for (const edge of edges) {
      graph.addTypedEdge(edge.source, edge.target, {
        compatible: edge.compatible,
        mismatches: edge.mismatches,
      });
    }
  }
  return graph;
}

describe("validatePreconditions", () => {
  it("returns empty for valid graph with no required fields", () => {
    const graph = createOperationGraph([
      { name: "a", outputSchema: Type.Object({ x: Type.Number() }) },
      { name: "b", inputSchema: Type.Object({}) },
    ]);
    graph.addEdge("test.a", "test.b");
    const errors = validatePreconditions(graph);
    expect(errors).toEqual([]);
  });

  it("returns empty when all required input fields are provided by predecessors", () => {
    const graph = createOperationGraph([
      { name: "a", outputSchema: Type.Object({ x: Type.Number(), y: Type.String() }) },
      { name: "b", inputSchema: Type.Object({ x: Type.Number() }) },
    ]);
    graph.addEdge("test.a", "test.b");
    const errors = validatePreconditions(graph);
    expect(errors).toEqual([]);
  });

  it("returns errors when required input field is not provided by any predecessor", () => {
    const graph = createOperationGraph([
      { name: "a", outputSchema: Type.Object({ x: Type.Number() }) },
      { name: "b", inputSchema: Type.Object({ x: Type.Number(), y: Type.String() }) },
    ]);
    graph.addEdge("test.a", "test.b");
    const errors = validatePreconditions(graph);
    expect(errors.length).toBeGreaterThan(0);
    const fieldNames = errors.map((e) => e.field);
    expect(fieldNames).toContain("y");
  });

  it("returns errors when node with required fields has no predecessors", () => {
    const graph = createOperationGraph([
      { name: "a", inputSchema: Type.Object({ x: Type.Number() }), outputSchema: Type.Object({}) },
    ]);
    const errors = validatePreconditions(graph);
    expect(errors.length).toBeGreaterThan(0);
    expect(errors[0]!.message).toContain("no predecessor");
  });

  it("collects provided fields from multiple predecessors", () => {
    const graph = createOperationGraph([
      { name: "a", outputSchema: Type.Object({ x: Type.Number() }) },
      { name: "c", outputSchema: Type.Object({ y: Type.String() }) },
      { name: "b", inputSchema: Type.Object({ x: Type.Number(), y: Type.String() }) },
    ]);
    graph.addEdge("test.a", "test.b");
    graph.addEdge("test.c", "test.b");
    const errors = validatePreconditions(graph);
    expect(errors).toEqual([]);
  });

  it("returns empty for graph with no nodes", () => {
    const graph = new FlowGraph() as OpGraph;
    const errors = validatePreconditions(graph);
    expect(errors).toEqual([]);
  });
});

describe("validateTemplate", () => {
  it("returns empty for valid template with all operations in graph", () => {
    const graph = createOperationGraphWithEdges([
      { name: "a", outputSchema: Type.Object({ x: Type.Number() }) },
      { name: "b", inputSchema: Type.Object({ x: Type.Number() }) },
    ], [
      { source: "test.a", target: "test.b", compatible: true },
    ]);
    const template = h(Sequential, {},
      h(Operation, { name: "test.a" }),
      h(Operation, { name: "test.b" }),
    );
    const errors = validateTemplate(template, graph);
    expect(errors).toEqual([]);
  });

  it("returns error when operation name is not in operation graph", () => {
    const graph = createOperationGraph([
      { name: "a" },
    ]);
    const template = h(Sequential, {},
      h(Operation, { name: "test.a" }),
      h(Operation, { name: "test.missing" }),
    );
    const errors = validateTemplate(template, graph);
    expect(errors.length).toBeGreaterThan(0);
    const missingErrors = errors.filter(
      (e) => e.type === "graph" && (e as { type: string; category: string; details: unknown }).category === "orphan-node"
        && JSON.stringify((e as { details: unknown }).details).includes("missing"),
    );
    expect(missingErrors.length).toBeGreaterThan(0);
  });

  it("returns error for type incompatibility between sequential operations", () => {
    const graph = createOperationGraphWithEdges([
      { name: "a", outputSchema: Type.Object({ x: Type.String() }) },
      { name: "b", inputSchema: Type.Object({ x: Type.Number() }) },
    ], [
      { source: "test.a", target: "test.b", compatible: false, mismatches: [{ path: "/x", expected: "number", actual: "string" }] },
    ]);
    const template = h(Sequential, {},
      h(Operation, { name: "test.a" }),
      h(Operation, { name: "test.b" }),
    );
    const errors = validateTemplate(template, graph);
    const typeErrors = errors.filter((e) => e.type === "type-compat");
    expect(typeErrors.length).toBeGreaterThan(0);
  });

  it("returns empty for single-operation template", () => {
    const graph = createOperationGraph([
      { name: "a" },
    ]);
    const template = h(Operation, { name: "test.a" });
    const errors = validateTemplate(template, graph);
    expect(errors).toEqual([]);
  });

  it("detects unreachable nodes", () => {
    const graph = createOperationGraphWithEdges([
      { name: "a" },
      { name: "b" },
      { name: "c" },
    ]);
    const template = h(Sequential, {},
      h(Operation, { name: "test.a" }),
      h(Operation, { name: "test.b" }),
    );
    const errors = validateTemplate(template, graph);
    const reachableErrors = errors.filter(
      (e) => e.type === "graph" && JSON.stringify((e as { details: unknown }).details).includes("not reachable"),
    );
    expect(reachableErrors.length).toBe(0);
  });

  it("returns empty for valid parallel template", () => {
    const graph = createOperationGraphWithEdges([
      { name: "a" },
      { name: "b" },
      { name: "c" },
    ]);
    const template = h(Sequential, {},
      h(Operation, { name: "test.a" }),
      h(Parallel, {},
        h(Operation, { name: "test.b" }),
        h(Operation, { name: "test.c" }),
      ),
    );
    const errors = validateTemplate(template, graph);
    expect(errors).toEqual([]);
  });

  it("handles template with conditional", () => {
    const graph = createOperationGraphWithEdges([
      { name: "a", outputSchema: Type.Object({ result: Type.Boolean() }) },
      { name: "b" },
      { name: "c" },
    ]);
    const template = h(Sequential, {},
      h(Operation, { name: "test.a" }),
      h(Conditional, { test: "test.a" },
        h(Operation, { name: "test.b" }),
      ),
      h(Operation, { name: "test.c" }),
    );
    const errors = validateTemplate(template, graph);
    expect(errors).toEqual([]);
  });

  it("template validation is advisory - never throws", () => {
    const graph = new FlowGraph() as OpGraph;
    const template = h(Sequential, {},
      h(Operation, { name: "nonexistent" }),
    );
    const errors = validateTemplate(template, graph);
    expect(Array.isArray(errors)).toBe(true);
  });

  it("detects orphan node with no edges in multi-node template", () => {
    const graph = createOperationGraphWithEdges([
      { name: "a" },
      { name: "b" },
    ]);
    const template = h(Parallel, {},
      h(Operation, { name: "test.a" }),
      h(Operation, { name: "test.b" }),
    );
    const errors = validateTemplate(template, graph);
    const orphanErrors = errors.filter(
      (e) => e.type === "graph" && (e as { type: string; category: string }).category === "orphan-node"
        && JSON.stringify((e as { details: unknown }).details).includes("no edges"),
    );
    expect(orphanErrors.length).toBeGreaterThan(0);
  });
});