// Test harness helpers for loading and asserting against Imhotep fixture pages.
// Uses dependency injection for all external dependencies.

import { readFile } from 'node:fs/promises'
import { resolve, dirname } from 'node:path'
import { fileURLToPath } from 'node:url'

const __dirname = dirname(fileURLToPath(import.meta.url))

// Resolve a fixture page path by category name.
// Returns the absolute path to the HTML file.
export function resolveFixturePage(category: string): string {
  const pagePath = resolve(__dirname, 'pages', `${category}.html`)
  return pagePath
}

// Load a fixture page as an HTML string.
// Accepts fs-like dependency for testability.
export async function loadFixturePage(
  category: string,
  deps: { fs?: { readFile: typeof readFile } } = {}
): Promise<string> {
  const fs = deps.fs || { readFile }
  const path = resolveFixturePage(category)
  const content = await fs.readFile(path, 'utf-8')
  return content
}

interface TestIdMatch {
  testId: string
  tag: string
  raw: string
}

// Simple HTML parser helper to extract elements by data-testid.
// Pure function for unit testing without a browser.
export function findByTestId(html: string, testId: string): TestIdMatch[] {
  const regex = new RegExp(`data-testid="${testId}"`, 'g')
  const matches: TestIdMatch[] = []
  let match: RegExpExecArray | null
  while ((match = regex.exec(html)) !== null) {
    // Walk backward to find the opening tag
    let start = match.index
    while (start > 0 && html[start] !== '<') {
      start--
    }
    // Walk forward to find the closing >
    let end = match.index
    while (end < html.length && html[end] !== '>') {
      end++
    }
    matches.push({
      testId,
      tag: html.slice(start, end + 1),
      raw: html.slice(start, end + 1),
    })
  }
  return matches
}

// Extract all data-testid values from fixture HTML.
// Useful for verifying fixture completeness.
export function extractAllTestIds(html: string): string[] {
  const regex = /data-testid="([^"]+)"/g
  const ids = new Set<string>()
  let match: RegExpExecArray | null
  while ((match = regex.exec(html)) !== null) {
    ids.add(match[1])
  }
  return Array.from(ids).sort()
}

// Assert that a fixture page contains expected test IDs.
// Pure assertion helper for use in tests.
export function assertFixtureStructure(html: string, expectedTestIds: string[]): boolean {
  const actualIds = extractAllTestIds(html)
  const missing = expectedTestIds.filter(id => !actualIds.includes(id))
  const unexpected = actualIds.filter(id => !expectedTestIds.includes(id))
  
  if (missing.length > 0 || unexpected.length > 0) {
    const errors = []
    if (missing.length > 0) {
      errors.push(`Missing testIds: ${missing.join(', ')}`)
    }
    if (unexpected.length > 0) {
      errors.push(`Unexpected testIds: ${unexpected.join(', ')}`)
    }
    throw new Error(`Fixture structure mismatch:\n${errors.join('\n')}`)
  }
  
  return true
}

// Build a Playwright page object helper for fixture loading.
// Accepts playwright page via dependency injection.
export async function loadFixtureInPage(
  page: any,
  category: string,
  deps: Record<string, unknown> = {}
): Promise<any> {
  const path = resolveFixturePage(category)
  const fileUrl = 'file://' + path
  await page.goto(fileUrl)
  return page
}

// Wait for a fixture page to be fully ready.
// Useful for ensuring CSS has applied before asserting.
export async function waitForFixtureReady(
  page: any,
  deps: { timeout?: number } = {}
): Promise<void> {
  const timeout = deps.timeout || 5000
  await page.waitForLoadState('networkidle', { timeout })
  // Give CSS transitions a moment to settle
  await page.waitForTimeout(100)
}

// Get computed styles for an element by testId.
// Returns a plain object of style properties.
export async function getComputedStyles(
  page: any,
  testId: string,
  properties: string[] = []
): Promise<Record<string, string>> {
  const selector = `[data-testid="${testId}"]`
  const element = await page.locator(selector).first()
  
  if (properties.length === 0) {
    return await element.evaluate((el: Element) => {
      const styles = window.getComputedStyle(el)
      const result: Record<string, string> = {}
      for (let i = 0; i < styles.length; i++) {
        const prop = styles[i]
        result[prop] = styles.getPropertyValue(prop)
      }
      return result
    })
  }
  
  return await element.evaluate(
    (el: Element, props: string[]) => {
      const styles = window.getComputedStyle(el)
      const result: Record<string, string> = {}
      for (const prop of props) {
        result[prop] = styles.getPropertyValue(prop)
      }
      return result
    },
    properties
  )
}

// Get bounding box for an element by testId.
// Returns { x, y, width, height } in viewport coordinates.
export async function getBoundingBox(
  page: any,
  testId: string
): Promise<{ x: number; y: number; width: number; height: number } | null> {
  const selector = `[data-testid="${testId}"]`
  const element = await page.locator(selector).first()
  return await element.boundingBox()
}

// Get all bounding boxes for elements matching a testId.
// Useful for ambiguous selector testing.
export async function getAllBoundingBoxes(
  page: any,
  testId: string
): Promise<Array<{ x: number; y: number; width: number; height: number } | null>> {
  const selector = `[data-testid="${testId}"]`
  const elements = await page.locator(selector).all()
  const boxes = []
  for (const element of elements) {
    const box = await element.boundingBox()
    boxes.push(box)
  }
  return boxes
}

// Materialize a state snapshot for an element.
// Supported states: 'default', 'hover', 'focus-visible', 'active'
export async function materializeState(
  page: any,
  testId: string,
  stateName: string,
  deps: { settleTime?: number } = {}
): Promise<void> {
  const selector = `[data-testid="${testId}"]`
  const element = await page.locator(selector).first()
  
  switch (stateName) {
    case 'default':
      // Ensure no special state is active
      await page.mouse.move(0, 0)
      await page.evaluate(() => (document.activeElement as HTMLElement)?.blur())
      break
    case 'hover':
      await element.hover()
      break
    case 'focus-visible':
      await element.focus()
      break
    case 'active':
      await element.dispatchEvent('mousedown')
      break
    default:
      throw new Error(`Unknown state: ${stateName}`)
  }
  
  // Allow CSS transitions to apply
  const settleTime = deps.settleTime || 150
  await page.waitForTimeout(settleTime)
}

// Fixture metadata registry.
// Maps category names to expected testIds and descriptions.
export const fixtureRegistry: Record<
  string,
  { description: string; expectedTestIds: string[] }
> = {
  relations: {
    description: 'Basic spatial relations: leftOf, rightOf, above, below, centeredWithin, alignedWith',
    expectedTestIds: [
      'box-left',
      'box-right',
      'box-top',
      'box-bottom',
      'container',
      'centered',
      'align-ref',
      'align-subject',
      'align-center-ref',
      'align-center-subject',
      'align-bottom-ref',
      'align-bottom-subject',
      'gap-a',
      'gap-b',
      'gap-c',
      'leftOf-rightOf',
      'above-below',
      'centeredWithin',
      'alignedWith-top',
      'alignedWith-center',
      'alignedWith-bottom',
      'gap-assertion',
    ],
  },
  frames: {
    description: 'Frame resolution: viewport, containing block, positioned ancestor, scroll container, named grid area',
    expectedTestIds: [
      'fixed-box',
      'containing-block',
      'absolute-child',
      'positioned-ancestor',
      'nested-absolute',
      'scroll-container',
      'scroll-item',
      'grid-container',
      'grid-header',
      'grid-sidebar',
      'grid-content',
      'grid-footer',
      'viewport-frame',
      'containing-block-frame',
      'positioned-ancestor-frame',
      'scroll-container-frame',
      'named-grid-area-frame',
    ],
  },
  responsive: {
    description: 'Responsive layouts: breakpoints, touch targets, color scheme, container queries',
    expectedTestIds: [
      'responsive-sidebar',
      'responsive-content',
      'touch-target',
      'theme-aware',
      'cq-container',
      'cq-item',
      'breakpoint-layout',
      'touch-target-responsive',
      'color-scheme-responsive',
      'container-query-responsive',
    ],
  },
  topology: {
    description: 'Topology: clipping, scroll, stacking contexts, formatting contexts',
    expectedTestIds: [
      'overflow-clip-container',
      'overflow-clipped-item',
      'clip-path-container',
      'clip-path-item',
      'scroll-port',
      'sticky-item',
      'stacking-root',
      'stack-bottom',
      'stack-top',
      'stack-peer-a',
      'stack-peer-b',
      'nested-stack-parent',
      'nested-stack-child',
      'nested-stack-grandchild',
      'fc-container',
      'float-box',
      'bfc-box',
      'overflow-clipping',
      'clip-path-clipping',
      'scroll-container',
      'stacking-context',
      'nested-stacking-context',
      'formatting-context',
    ],
  },
  states: {
    description: 'UI states: hover, focus-visible, active, disabled, checked, expanded, selected, pressed, visited',
    expectedTestIds: [
      'hover-btn',
      'hover-card-el',
      'focus-input',
      'focus-btn',
      'state-box-a',
      'state-box-b',
      'active-btn',
      'hover-button',
      'hover-card',
      'focus-visible-input',
      'focus-visible-button',
      'state-comparison',
      'active-state',
      'disabled-btn',
      'disabled-state',
      'checked-input',
      'checked-state',
      'expand-btn',
      'expand-panel',
      'expanded-state',
      'selected-option',
      'selected-state',
      'pressed-btn',
      'pressed-state',
      'visited-link',
      'visited-state',
    ],
  },
  errors: {
    description: 'Invalid authoring: ambiguous selectors, missing subjects',
    expectedTestIds: [
      'ambiguous-1',
      'ambiguous-2',
      'ambiguous-3',
      'existing-el',
      'empty-target-el',
      'nested-ambiguous-1',
      'nested-ambiguous-2',
      'ambiguous-selector',
      'missing-subject',
      'empty-selector',
      'nested-ambiguous',
    ],
  },
}

// List all available fixture categories.
export function listFixtureCategories(): string[] {
  return Object.keys(fixtureRegistry)
}

// Get metadata for a specific fixture category.
export function getFixtureMetadata(
  category: string
): { description: string; expectedTestIds: string[] } | null {
  return fixtureRegistry[category] || null
}