// browser-side evaluator snippets for CLI inspect commands.
//
// the rnx CLI ships some commands that need to observe the live
// rnx tree or its rendered pixels. we send these strings over the rnx host's
// `evaluate` handler.
//
// cropping happens once, in the capture module (`bridges.screenshot`),
// via its `crop` option. these evals intentionally defer to that bridge
// instead of reimplementing the dpr-aware crop math.

export interface SampleRect {
  x: number
  y: number
  w: number
  h: number
}

// resolve a --id/--text matcher into a SampleRect using __sootsimTest.
// returns null on miss so the caller can report a clear not-found error.
export function buildResolveRectEval(matcher: { id?: string; text?: string }): string {
  return `(async () => {
    const __t = window.__sootsimTest
    if (!__t) throw new Error('__sootsimTest not available')
    const __id = ${JSON.stringify(matcher.id || '')}
    const __text = ${JSON.stringify(matcher.text || '')}
    let __node = null
    if (__id) {
      __node = (__t.findByTestId && await __t.findByTestId(__id)) ||
               (__t.findById && await __t.findById(__id)) || null
    } else if (__text) {
      __node = __t.findByText ? await __t.findByText(__text) : null
    }
    if (!__node) return null
    const __pos = __node.absolutePosition || { x: __node.layout?.x || 0, y: __node.layout?.y || 0 }
    const __layout = __node.layout || {}
    return {
      x: __pos.x,
      y: __pos.y,
      w: __layout.width || 1,
      h: __layout.height || 1,
    }
  })()`
}

// sample-color averages rgba pixels across a logical-coord rect. the eval
// asks the capture bridge for an already-cropped PNG and then averages the
// decoded ImageData in one pass.
export function buildSampleColorEval(rect: SampleRect): string {
  return `(async () => {
    const __rect = ${JSON.stringify(rect)}
    const __screenshot = window.__sootsimScreenshot
    if (typeof __screenshot !== 'function') {
      throw new Error('screenshot bridge not installed')
    }
    const __dataUrl = await __screenshot({ crop: __rect })
    const __img = await new Promise((res, rej) => {
      const img = new Image()
      img.onload = () => res(img)
      img.onerror = () => rej(new Error('failed to decode cropped screenshot'))
      img.src = __dataUrl
    })
    const __w = __img.naturalWidth
    const __h = __img.naturalHeight
    const __canvas = document.createElement('canvas')
    __canvas.width = __w
    __canvas.height = __h
    const __ctx = __canvas.getContext('2d')
    if (!__ctx) throw new Error('could not acquire 2d context')
    __ctx.drawImage(__img, 0, 0)
    const __data = __ctx.getImageData(0, 0, __w, __h).data
    const __n = __data.length / 4
    let __r = 0, __g = 0, __b = 0, __a = 0
    for (let __i = 0; __i < __data.length; __i += 4) {
      __r += __data[__i]
      __g += __data[__i + 1]
      __b += __data[__i + 2]
      __a += __data[__i + 3]
    }
    const __round = (v) => Math.round(v / __n)
    const __rr = __round(__r), __gg = __round(__g), __bb = __round(__b), __aa = __round(__a)
    const __hex =
      '#' +
      [__rr, __gg, __bb]
        .map((v) => v.toString(16).padStart(2, '0'))
        .join('')
    const __dpr = window.devicePixelRatio || 1
    return {
      r: __rr, g: __gg, b: __bb, a: __aa,
      hex: __hex,
      samples: __n,
      rect: { x: __rect.x, y: __rect.y, w: __rect.w, h: __rect.h },
      deviceWidth: __w / __dpr,
      deviceHeight: __h / __dpr,
    }
  })()`
}