import { describe, expect, it } from 'vitest'
import fs from 'node:fs'
import path from 'node:path'
import zlib from 'node:zlib'
import {
  MISSILE_METAS,
  HOWL_META,
  SHOUT_META,
  BATTLECRY_META,
  BATTLEORDERS_META,
  BATTLECOMMAND_META,
  WARCRY_META,
  GRIMWARDSMALLSTART_META,
  GRIMWARDSMALL_META,
  GRIMWARDSMALLSTOP_META,
  GRIMWARDMEDIUMSTART_META,
  GRIMWARDMEDIUM_META,
  GRIMWARDMEDIUMSTOP_META,
  GRIMWARDLARGESTART_META,
  GRIMWARDLARGE_META,
  GRIMWARDLARGESTOP_META,
  type MissileMeta,
} from '../../../src/client/render/missiles-meta.ts'
import {
  OVERLAY_METAS,
  ALL_OVERLAY_NAMES,
  SHOUTSTART_OVERLAY_META,
  SHOUT_OVERLAY_META,
  BATTLECRY_OVERLAY_META,
  BATTLEORDERSCAST_OVERLAY_META,
  BATTLEORDERS_OVERLAY_META,
  BATTLECOMMANDCAST_OVERLAY_META,
  BATTLECOMMAND_OVERLAY_META,
  BERSERKFRONT_OVERLAY_META,
  FRENZY_OVERLAY_META,
  WARCRY_OVERLAY_META,
  TAUNT_OVERLAY_META,
  STUN_OVERLAY_META,
  type OverlayMeta,
} from '../../../src/client/render/overlays-meta.ts'
import { BATCH1_SKILLS } from '../../../src/server/skills/skills.ts'

// Strict PNG RGBA Decoder (validates colorType === 6, bitDepth === 8, and pixel transparency)
function decodeRgbaPng(buf: Buffer) {
  const width = buf.readUInt32BE(16)
  const height = buf.readUInt32BE(20)
  const bitDepth = buf[24]!
  const colorType = buf[25]!

  const idatParts: Buffer[] = []
  let offset = 8
  while (offset < buf.length) {
    const len = buf.readUInt32BE(offset)
    const type = buf.subarray(offset + 4, offset + 8).toString('ascii')
    if (type === 'IDAT') {
      idatParts.push(buf.subarray(offset + 8, offset + 8 + len))
    }
    offset += 12 + len
  }
  const idat = Buffer.concat(idatParts)
  const raw = zlib.inflateSync(idat)

  const bpp = 4
  const rowBytes = width * bpp
  const pixels = new Uint8Array(width * height * 4)
  let srcAt = 0
  let dstAt = 0

  for (let y = 0; y < height; y++) {
    const filter = raw[srcAt++]
    const row = raw.subarray(srcAt, srcAt + rowBytes)
    srcAt += rowBytes

    const prevRow = y > 0 ? pixels.subarray((y - 1) * rowBytes, y * rowBytes) : null
    const curRow = pixels.subarray(dstAt, dstAt + rowBytes)

    for (let x = 0; x < rowBytes; x++) {
      const left = x >= bpp ? curRow[x - bpp]! : 0
      const up = prevRow ? prevRow[x]! : 0
      const upLeft = prevRow && x >= bpp ? prevRow[x - bpp]! : 0

      let val = row[x]!
      if (filter === 0) {
        // None
      } else if (filter === 1) {
        val = (val + left) & 0xff
      } else if (filter === 2) {
        val = (val + up) & 0xff
      } else if (filter === 3) {
        val = (val + Math.floor((left + up) / 2)) & 0xff
      } else if (filter === 4) {
        const p = left + up - upLeft
        const pa = Math.abs(p - left)
        const pb = Math.abs(p - up)
        const pc = Math.abs(p - upLeft)
        let pr = upLeft
        if (pa <= pb && pa <= pc) pr = left
        else if (pb <= pc) pr = up
        val = (val + pr) & 0xff
      }
      curRow[x] = val
    }
    dstAt += rowBytes
  }

  return { width, height, bitDepth, colorType, pixels }
}

describe('Milestone M16 — Barbarian Asset Packaging & Registration', () => {
  const publicMissilesDir = path.resolve(__dirname, '../../../public/missiles')
  const packMissilesDir = path.resolve(__dirname, '../../../samples/d2-packs/missiles')
  const publicOverlaysDir = path.resolve(__dirname, '../../../public/overlays')
  const packOverlaysDir = path.resolve(__dirname, '../../../samples/d2-packs/overlays')

  const BARBARIAN_MISSILES = [
    { name: 'howl', celFile: 'BAYellShockWave01', meta: HOWL_META, trans: 1 },
    { name: 'shout', celFile: 'BAYellShockWave01', meta: SHOUT_META, trans: 1 },
    { name: 'battlecry', celFile: 'BAYellShockWave01', meta: BATTLECRY_META, trans: 1 },
    { name: 'battleorders', celFile: 'BAYellShockWave01', meta: BATTLEORDERS_META, trans: 1 },
    { name: 'battlecommand', celFile: 'BAYellShockWave01', meta: BATTLECOMMAND_META, trans: 1 },
    { name: 'warcry', celFile: 'WarcryShockwave', meta: WARCRY_META, trans: 1 },
    { name: 'grimwardsmallstart', celFile: 'GrimWardSmallStart', meta: GRIMWARDSMALLSTART_META, trans: 0 },
    { name: 'grimwardsmall', celFile: 'GrimWardSmall', meta: GRIMWARDSMALL_META, trans: 0 },
    { name: 'grimwardsmallstop', celFile: 'GrimWardSmallStop', meta: GRIMWARDSMALLSTOP_META, trans: 0 },
    { name: 'grimwardmediumstart', celFile: 'GrimWardMediumStart', meta: GRIMWARDMEDIUMSTART_META, trans: 0 },
    { name: 'grimwardmedium', celFile: 'GrimWardMedium', meta: GRIMWARDMEDIUM_META, trans: 0 },
    { name: 'grimwardmediumstop', celFile: 'GrimWardMediumStop', meta: GRIMWARDMEDIUMSTOP_META, trans: 0 },
    { name: 'grimwardlargestart', celFile: 'GrimWardLargeStart', meta: GRIMWARDLARGESTART_META, trans: 0 },
    { name: 'grimwardlarge', celFile: 'GrimWardLarge', meta: GRIMWARDLARGE_META, trans: 0 },
    { name: 'grimwardlargestop', celFile: 'GrimWardLargeStop', meta: GRIMWARDLARGESTOP_META, trans: 0 },
  ] as const

  const BARBARIAN_OVERLAYS = [
    { name: 'shoutstart', celFile: 'ShoutStart', meta: SHOUTSTART_OVERLAY_META },
    { name: 'shout', celFile: 'Shout', meta: SHOUT_OVERLAY_META },
    { name: 'battlecry', celFile: 'BattleCry', meta: BATTLECRY_OVERLAY_META },
    { name: 'battleorderscast', celFile: 'BattleOrdersStart', meta: BATTLEORDERSCAST_OVERLAY_META },
    { name: 'battleorders', celFile: 'BattleOrders', meta: BATTLEORDERS_OVERLAY_META },
    { name: 'battlecommandcast', celFile: 'BattleCommandStart', meta: BATTLECOMMANDCAST_OVERLAY_META },
    { name: 'battlecommand', celFile: 'BattleCommand', meta: BATTLECOMMAND_OVERLAY_META },
    { name: 'berserkfront', celFile: 'BerserkOverlay', meta: BERSERKFRONT_OVERLAY_META },
    { name: 'frenzy', celFile: 'Frenzy', meta: FRENZY_OVERLAY_META },
    { name: 'warcry', celFile: 'WarcryHit', meta: WARCRY_OVERLAY_META },
  ] as const

  // =========================================================================
  // Suite 1: Physical Asset Existence & Dual Mirroring
  // =========================================================================
  describe('Suite 1: Physical Asset Existence & Dual Mirroring', () => {
    it('1.1 Verifies all 15 Barbarian missiles exist in both public/ and samples/d2-packs/', () => {
      for (const m of BARBARIAN_MISSILES) {
        for (const dir of [publicMissilesDir, packMissilesDir]) {
          const pngPath = path.join(dir, `${m.name}.png`)
          const jsonPath = path.join(dir, `${m.name}.json`)

          expect(fs.existsSync(pngPath), `Missing missile PNG: ${pngPath}`).toBe(true)
          expect(fs.existsSync(jsonPath), `Missing missile JSON: ${jsonPath}`).toBe(true)

          const stat = fs.statSync(pngPath)
          expect(stat.size, `${pngPath} must be > 1000 bytes`).toBeGreaterThan(1000)

          const buf = fs.readFileSync(pngPath)
          expect(buf.readUInt32BE(0)).toBe(0x89504e47) // PNG signature
        }
      }
    })

    it('1.2 Verifies all 10 Barbarian overlays exist in both public/ and samples/d2-packs/', () => {
      for (const o of BARBARIAN_OVERLAYS) {
        for (const dir of [publicOverlaysDir, packOverlaysDir]) {
          const pngPath = path.join(dir, `${o.name}.png`)
          const jsonPath = path.join(dir, `${o.name}.json`)

          expect(fs.existsSync(pngPath), `Missing overlay PNG: ${pngPath}`).toBe(true)
          expect(fs.existsSync(jsonPath), `Missing overlay JSON: ${jsonPath}`).toBe(true)

          const stat = fs.statSync(pngPath)
          expect(stat.size, `${pngPath} must be > 1000 bytes`).toBeGreaterThan(1000)

          const buf = fs.readFileSync(pngPath)
          expect(buf.readUInt32BE(0)).toBe(0x89504e47) // PNG signature
        }
      }
    })
  })

  // =========================================================================
  // Suite 2: Metadata Registry & Contract Verification
  // =========================================================================
  describe('Suite 2: Metadata Registry & Typed Contract Integrity', () => {
    it('2.1 Verifies all Barbarian missiles registered in MISSILE_METAS with matching properties', () => {
      for (const m of BARBARIAN_MISSILES) {
        const registered = MISSILE_METAS[m.name]
        expect(registered, `MISSILE_METAS missing '${m.name}'`).toBeDefined()
        expect(registered!.name).toBe(m.name)
        expect(registered!.celFile).toBe(m.celFile)
        expect(registered!.width).toBeGreaterThan(0)
        expect(registered!.height).toBeGreaterThan(0)
        expect(registered!.directions).toBeGreaterThan(0)
        expect(registered!.framesPerDirection).toBeGreaterThan(0)
        expect(registered!.groups.length).toBe(registered!.directions)

        // Verify CelFile alias lookup
        const celLookup = MISSILE_METAS[m.celFile]
        expect(celLookup, `CelFile lookup missing for ${m.celFile}`).toBeDefined()
        expect(celLookup!.celFile).toBe(m.celFile)
      }
    })

    it('2.2 Verifies all Barbarian overlays registered in OVERLAY_METAS and ALL_OVERLAY_NAMES', () => {
      for (const o of BARBARIAN_OVERLAYS) {
        expect(ALL_OVERLAY_NAMES).toContain(o.name)
        const registered = OVERLAY_METAS[o.name]
        expect(registered, `OVERLAY_METAS missing '${o.name}'`).toBeDefined()
        expect(registered!.name).toBe(o.name)
        expect(registered!.celFile).toBe(o.celFile)
        expect(registered!.frames).toBeGreaterThan(0)
        expect(registered!.groups.length).toBe(registered!.directions)
        expect(registered!.box).toBeDefined()
        expect(registered!.box.width).toBeGreaterThan(0)
        expect(registered!.box.height).toBeGreaterThan(0)
      }
    })

    it('2.3 Verifies Taunt (#137) and Stun (#139) alias contracts', () => {
      expect(TAUNT_OVERLAY_META).toBeDefined()
      expect(TAUNT_OVERLAY_META.celFile).toBe('CurseConfuseEffect')
      expect(OVERLAY_METAS['taunt']).toBe(TAUNT_OVERLAY_META)

      expect(STUN_OVERLAY_META).toBeDefined()
      expect(STUN_OVERLAY_META.celFile).toBe('Stun')
      expect(OVERLAY_METAS['stun']).toBe(STUN_OVERLAY_META)
    })
  })

  // =========================================================================
  // Suite 3: Transparency & Edge Artifact Audit (Zero Dark Borders)
  // =========================================================================
  describe('Suite 3: Transparency & Alpha Ramp Audit (No Black Box Fringe)', () => {
    it('3.1 Audits Warcry shockwave missiles for true Trans=1 additive blending', () => {
      for (const m of ['howl', 'shout', 'battlecry', 'battleorders', 'battlecommand', 'warcry']) {
        const pngPath = path.join(publicMissilesDir, `${m}.png`)
        const buf = fs.readFileSync(pngPath)
        const { width, height, pixels } = decodeRgbaPng(buf)

        let transparentCount = 0
        let opaqueOrSemiCount = 0
        let blackOpaqueCount = 0

        for (let i = 0; i < pixels.length; i += 4) {
          const r = pixels[i]!
          const g = pixels[i + 1]!
          const b = pixels[i + 2]!
          const a = pixels[i + 3]!

          if (a === 0) {
            transparentCount++
          } else {
            opaqueOrSemiCount++
            // Fringe dark border check: if max(r,g,b) <= 4, alpha MUST be 0
            if (Math.max(r, g, b) <= 4 && a > 0) {
              blackOpaqueCount++
            }
          }
        }

        expect(transparentCount, `${m} must have transparent pixels`).toBeGreaterThan(0)
        expect(opaqueOrSemiCount, `${m} must have non-transparent pixels`).toBeGreaterThan(0)
        expect(blackOpaqueCount, `${m} has black fringe pixels with non-zero alpha`).toBe(0)
      }
    })

    it('3.2 Audits Barbarian overlays for authentic Trans=3 blending (no background border smudge)', () => {
      for (const o of BARBARIAN_OVERLAYS) {
        const pngPath = path.join(publicOverlaysDir, `${o.name}.png`)
        const buf = fs.readFileSync(pngPath)
        const { width, height, pixels } = decodeRgbaPng(buf)

        let transparentCount = 0
        let opaqueOrSemiCount = 0
        let blackOpaqueCount = 0

        for (let i = 0; i < pixels.length; i += 4) {
          const r = pixels[i]!
          const g = pixels[i + 1]!
          const b = pixels[i + 2]!
          const a = pixels[i + 3]!

          if (a === 0) {
            transparentCount++
          } else {
            opaqueOrSemiCount++
            if (Math.max(r, g, b) <= 4 && a > 0) {
              blackOpaqueCount++
            }
          }
        }

        expect(transparentCount, `${o.name} must have transparent pixels`).toBeGreaterThan(0)
        expect(opaqueOrSemiCount, `${o.name} must have rendered pixels`).toBeGreaterThan(0)
        expect(blackOpaqueCount, `${o.name} must have 0 dark opaque border pixels`).toBe(0)
      }
    })
  })

  // =========================================================================
  // Suite 4: Invariant & Regression Guardrails
  // =========================================================================
  describe('Suite 4: Invariants & Regression Guardrails', () => {
    it('4.1 Enforces BATCH1_SKILLS length invariant = exactly 38', () => {
      expect(Object.keys(BATCH1_SKILLS).length).toBe(38)
    })

    it('4.2 Enforces all 15 Barbarian missiles have valid bounding frame boxes and non-negative anchors', () => {
      for (const m of BARBARIAN_MISSILES) {
        const meta = m.meta
        for (const dirGroup of meta.groups) {
          for (const frame of dirGroup) {
            const [x, y, w, h, ax, ay] = frame
            expect(x).toBeGreaterThanOrEqual(0)
            expect(y).toBeGreaterThanOrEqual(0)
            expect(w).toBeGreaterThan(0)
            expect(h).toBeGreaterThan(0)
            expect(x + w).toBeLessThanOrEqual(meta.width)
            expect(y + h).toBeLessThanOrEqual(meta.height)
          }
        }
      }
    })
  })
})