import { describe, expect, test } from "vitest"
import { DRLGROOMTILE_GetTileCache } from "../src/game/wilderness.ts"
import { Rng } from "../src/game/rng.ts"
import type { Dt1, Dt1Tile } from "../src/formats/dt1.ts"

function makeMockDt1(tiles: (Partial<Dt1Tile> & { rarity?: number; Rarity?: number })[]): Dt1 {
  return {
    warnings: [],
    versionMajor: 7,
    versionMinor: 6,
    tiles: tiles.map(t => ({
      direction: 0,
      height: -80,
      width: 160,
      type: t.type ?? 0,
      style: t.style ?? 0,
      sequence: t.sequence ?? 0,
      materialFlags: 0,
      roofHeight: 0,
      animated: t.animated ?? 0,
      rarityFrameIndex: t.rarityFrameIndex ?? 1,
      subTileFlags: [],
      minBlockY: 0,
      bitmapHeight: 80,
      blocks: [],
      ...t,
    })),
  }
}

describe("DRLGROOMTILE_GetTileCache deterministic seed (Issue #78)", () => {
  const dt1 = makeMockDt1([
    { type: 0, style: 0, sequence: 0, rarityFrameIndex: 20 },
    { type: 0, style: 0, sequence: 1, rarityFrameIndex: 30 },
    { type: 0, style: 0, sequence: 2, rarityFrameIndex: 50 },
  ])

  describe("same seed produces identical result", () => {
    test("same integer seed produces identical tile selection across multiple invocations", () => {
      const query1 = { type: 0, seed: 12345 }
      const query2 = { type: 0, seed: 12345 }

      const res1 = DRLGROOMTILE_GetTileCache([dt1], 1, query1)
      const res2 = DRLGROOMTILE_GetTileCache([dt1], 1, query2)

      expect(res1).not.toBeNull()
      expect(res2).not.toBeNull()
      expect(res1).toEqual(res2)
    })

    test("same coordinates and seed produce identical tile selection", () => {
      const resA = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: 99999, x: 15, y: 27 })
      const resB = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: 99999, x: 15, y: 27 })

      expect(resA).not.toBeNull()
      expect(resA).toEqual(resB)
    })

    test("same direct fractional roll produces identical tile selection", () => {
      const resA = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: 0.45 })
      const resB = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: 0.45 })

      expect(resA).not.toBeNull()
      expect(resA).toEqual(resB)
    })

    test("identical Rng seeds produce identical sequences of tile selections", () => {
      const rng1 = new Rng(88888)
      const rng2 = new Rng(88888)

      const results1 = Array.from({ length: 20 }, () =>
        DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: rng1 })?.sequence,
      )
      const results2 = Array.from({ length: 20 }, () =>
        DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: rng2 })?.sequence,
      )

      expect(results1).toEqual(results2)
    })
  })

  describe("different seeds produce varying selections over multiple runs", () => {
    test("varying integer seeds select different tiles across runs", () => {
      const seenSequences = new Set<number>()

      for (let s = 0; s < 50; s += 1) {
        const res = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: s * 1000 + 7 })
        if (res !== null) {
          seenSequences.add(res.sequence)
        }
      }

      // All 3 candidate sequences (0, 1, 2) should be selected across 50 distinct seeds
      expect(seenSequences.size).toBe(3)
      expect(seenSequences.has(0)).toBe(true)
      expect(seenSequences.has(1)).toBe(true)
      expect(seenSequences.has(2)).toBe(true)
    })

    test("varying coordinates with same seed select different tiles", () => {
      const seenSequences = new Set<number>()

      for (let x = 0; x < 50; x += 1) {
        const res = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: 12345, x, y: 0 })
        if (res !== null) {
          seenSequences.add(res.sequence)
        }
      }

      expect(seenSequences.size).toBeGreaterThan(1)
    })

    test("consecutive draws from a single Rng produce varying selections", () => {
      const rng = new Rng(42)
      const seenSequences = new Set<number>()

      for (let i = 0; i < 50; i += 1) {
        const res = DRLGROOMTILE_GetTileCache([dt1], 1, { type: 0, seed: rng })
        if (res !== null) {
          seenSequences.add(res.sequence)
        }
      }

      expect(seenSequences.size).toBe(3)
    })
  })
})