import { describe, expect, test } from "vitest"
import { readFileSync } from "node:fs"
import { resolve } from "node:path"
import * as wilderness from "../src/game/wilderness.ts"
import * as maze from "../src/game/maze.ts"
import * as levelLinks from "../src/game/level-links.ts"

describe("DRLG Export and Alias Guard (Issue #81)", () => {
  const getDrlgExports = (mod: Record<string, unknown>): string[] => {
    return Object.keys(mod).filter((name) => name.startsWith("DRLG"))
  }

  test("src/game/wilderness.ts does not export fake Blizzard aliases", () => {
    const exports = getDrlgExports(wilderness as Record<string, unknown>)
    expect(exports).not.toContain("DRLGROOMTILE_ComputeNeighborMask")
    expect(exports).not.toContain("DRLGROOMTILE_ApplyTransitions")

    // The genuine custom functions should remain exported as local names
    expect(typeof (wilderness as Record<string, unknown>).computeNeighborMask).toBe("function")
    expect(typeof (wilderness as Record<string, unknown>).applyGroundTransitions).toBe("function")
  })

  test("src/game/wilderness.ts keeps single export of DRLGOUTDOORS_SpawnAct12Waypoint", () => {
    const exports = getDrlgExports(wilderness as Record<string, unknown>)
    expect(exports).toContain("DRLGOUTDOORS_SpawnAct12Waypoint")
    expect(typeof wilderness.DRLGOUTDOORS_SpawnAct12Waypoint).toBe("function")
  })

  test("src/game/level-links.ts does not export duplicate DRLGOUTDOORS_SpawnAct12Waypoint", () => {
    const exports = getDrlgExports(levelLinks as Record<string, unknown>)
    expect(exports).not.toContain("DRLGOUTDOORS_SpawnAct12Waypoint")
    expect(exports).not.toContain("DRLGROOMTILE_ComputeNeighborMask")
    expect(exports).not.toContain("DRLGROOMTILE_ApplyTransitions")

    // findWaypointSpot remains exported as a local helper
    expect(typeof levelLinks.findWaypointSpot).toBe("function")
  })

  test("src/game/maze.ts does not export fake Blizzard DRLG aliases", () => {
    const exports = getDrlgExports(maze as Record<string, unknown>)
    expect(exports).not.toContain("DRLGROOMTILE_ComputeNeighborMask")
    expect(exports).not.toContain("DRLGROOMTILE_ApplyTransitions")
    expect(exports).not.toContain("DRLGOUTDOORS_SpawnAct12Waypoint")
  })

  test("DRLGOUTDOORS_SpawnAct12Waypoint has at most ONE export across wilderness, maze, and level-links", () => {
    const allDrlgExports = [
      ...getDrlgExports(wilderness as Record<string, unknown>),
      ...getDrlgExports(maze as Record<string, unknown>),
      ...getDrlgExports(levelLinks as Record<string, unknown>),
    ]

    const waypointExports = allDrlgExports.filter((name) => name === "DRLGOUTDOORS_SpawnAct12Waypoint")
    expect(waypointExports).toHaveLength(1)
  })

  test("Static source check: no fake DRLG export statements in source files", () => {
    const files = [
      resolve(__dirname, "../src/game/wilderness.ts"),
      resolve(__dirname, "../src/game/maze.ts"),
      resolve(__dirname, "../src/game/level-links.ts"),
    ]

    for (const filePath of files) {
      const source = readFileSync(filePath, "utf-8")
      expect(source).not.toMatch(/export\s+(?:const|function|let|var)\s+DRLGROOMTILE_ComputeNeighborMask\b/)
      expect(source).not.toMatch(/export\s+(?:const|function|let|var)\s+DRLGROOMTILE_ApplyTransitions\b/)
    }

    // Ensure level-links.ts does not export DRLGOUTDOORS_SpawnAct12Waypoint
    const levelLinksSource = readFileSync(resolve(__dirname, "../src/game/level-links.ts"), "utf-8")
    expect(levelLinksSource).not.toMatch(/export\s+(?:const|function|let|var)\s+DRLGOUTDOORS_SpawnAct12Waypoint\b/)

    // Ensure wilderness.ts has doc comments clarifying custom web port algorithms
    const wildernessSource = readFileSync(resolve(__dirname, "../src/game/wilderness.ts"), "utf-8")
    expect(wildernessSource).toMatch(/NOT a Blizzard original[\s\S]*?function computeNeighborMask/)
    expect(wildernessSource).toMatch(/NOT a Blizzard original[\s\S]*?function applyGroundTransitions/)
  })
})