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

import {
  addPrerequisite,
  buildPrereqRows,
  dependsOn,
  removePrerequisite,
  setPrerequisiteKind,
  withPrereqs,
} from "@/components/admin/tech-tree/prereqEdits";
import type { TreeTech } from "@/components/admin/tech-tree/types";

const tech = (over: Partial<TreeTech> & { id: number }): TreeTech => ({
  name: `Tech ${over.id}`,
  type: "upgrade",
  approvalStatus: "in_progress",
  summary: "",
  categoryId: null,
  prereqAnd: [],
  prereqOr: [],
  resourceCosts: [],
  treePosition: null,
  ...over,
});

describe("tech tree prerequisite edits (pure)", () => {
  it("adds an AND prerequisite", () => {
    const techs = [tech({ id: 1 }), tech({ id: 2 })];
    const result = addPrerequisite(techs, 2, 1, "and");
    expect(result.ok).toBe(true);
    if (result.ok) expect(result.lists).toEqual({ and: [1], or: [] });
  });

  it("adds an OR prerequisite", () => {
    const techs = [tech({ id: 1 }), tech({ id: 2 })];
    const result = addPrerequisite(techs, 2, 1, "or");
    expect(result.ok).toBe(true);
    if (result.ok) expect(result.lists).toEqual({ and: [], or: [1] });
  });

  it("rejects self references", () => {
    const result = addPrerequisite([tech({ id: 1 })], 1, 1, "and");
    expect(result.ok).toBe(false);
    if (!result.ok) expect(result.error).toMatch(/own prerequisite/i);
  });

  it("rejects duplicates", () => {
    const techs = [tech({ id: 1 }), tech({ id: 2, prereqAnd: [1] })];
    const result = addPrerequisite(techs, 2, 1, "or");
    expect(result.ok).toBe(false);
    if (!result.ok) expect(result.error).toMatch(/already a prerequisite/i);
  });

  it("rejects a direct cycle", () => {
    const techs = [tech({ id: 1, prereqAnd: [2] }), tech({ id: 2 })];
    // Adding 1 as a prerequisite of 2 would close 2 -> 1 -> 2.
    const result = addPrerequisite(techs, 2, 1, "and");
    expect(result.ok).toBe(false);
    if (!result.ok) expect(result.error).toMatch(/circular/i);
  });

  it("rejects a transitive cycle", () => {
    const techs = [
      tech({ id: 1 }),
      tech({ id: 2, prereqAnd: [1] }),
      tech({ id: 3, prereqAnd: [2] }),
    ];
    // 3 depends on 1 transitively; making 3 a prerequisite of 1 closes a loop.
    expect(dependsOn(techs, 3, 1)).toBe(true);
    const result = addPrerequisite(techs, 1, 3, "and");
    expect(result.ok).toBe(false);
  });

  it("allows a forward chain", () => {
    const techs = [tech({ id: 1 }), tech({ id: 2, prereqAnd: [1] }), tech({ id: 3 })];
    const result = addPrerequisite(techs, 3, 2, "and");
    expect(result.ok).toBe(true);
    if (result.ok) expect(result.lists).toEqual({ and: [2], or: [] });
  });

  it("removes a prerequisite from both groups", () => {
    const techs = [tech({ id: 1 }), tech({ id: 2, prereqAnd: [1], prereqOr: [1, 3] })];
    const result = removePrerequisite(techs, 2, 1);
    expect(result.ok).toBe(true);
    if (result.ok) expect(result.lists).toEqual({ and: [], or: [3] });
  });

  it("moves a prerequisite between AND and OR", () => {
    const techs = [tech({ id: 1 }), tech({ id: 2, prereqAnd: [1] })];
    const toOr = setPrerequisiteKind(techs, 2, 1, "or");
    expect(toOr.ok).toBe(true);
    if (toOr.ok) expect(toOr.lists).toEqual({ and: [], or: [1] });

    const back = setPrerequisiteKind(techs, 2, 1, "and");
    expect(back.ok).toBe(true);
    if (back.ok) expect(back.lists).toEqual({ and: [1], or: [] });
  });

  it("builds a single document-shaped prerequisite row", () => {
    expect(buildPrereqRows({ and: [1, 2], or: [3] })).toEqual([
      { requiresAnd: { technology: [1, 2] }, requiresOr: { technology: [3] } },
    ]);
  });

  it("withPrereqs returns a tech carrying the new lists", () => {
    const updated = withPrereqs(tech({ id: 1 }), { and: [4], or: [5] });
    expect(updated.prereqAnd).toEqual([4]);
    expect(updated.prereqOr).toEqual([5]);
  });
});