import { describe, it, expect } from 'vitest'
import * as fc from 'fast-check'
import {
  isParameterCoveredByInventory,
  suggestInventoryPath,
} from '../../app/utils/inventory_coverage.js'

/**
 * **Validates: Requirements 5.5**
 *
 * Property 9: Desired parameters require inventory coverage
 * Verifies subtree prefix matching logic using random TR-069-like paths.
 */

// Arbitrary: generates a single TR-069 path segment (alphanumeric, 1-10 chars)
const segmentArb = fc.array(
  fc.constantFrom(...'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.split('')),
  { minLength: 1, maxLength: 10 }
).map((chars) => chars.join(''))

// Arbitrary: generates a TR-069-like dot-separated path with 2-5 segments (e.g. "Device.Info.Param")
const tr069PathArb = fc.array(segmentArb, { minLength: 2, maxLength: 5 }).map((segments) => segments.join('.'))

// Arbitrary: generates a subtree path (ends with dot) from a TR-069 path by removing the last segment
const subtreePathFromParamArb = tr069PathArb.map((paramPath) => {
  const parts = paramPath.split('.')
  parts.pop()
  return { paramPath, subtreePath: parts.join('.') + '.' }
})

describe('Property 9: Inventory coverage validation', () => {
  it('a parameter is always covered by its own subtree path', () => {
    fc.assert(
      fc.property(subtreePathFromParamArb, ({ paramPath, subtreePath }) => {
        const result = isParameterCoveredByInventory(paramPath, [{ path: subtreePath }])
        expect(result).toBe(true)
      }),
      { numRuns: 200 }
    )
  })

  it('suggestInventoryPath always produces a path that covers the original parameter', () => {
    fc.assert(
      fc.property(tr069PathArb, (paramPath) => {
        const suggested = suggestInventoryPath(paramPath)
        const result = isParameterCoveredByInventory(paramPath, [{ path: suggested }])
        expect(result).toBe(true)
      }),
      { numRuns: 200 }
    )
  })

  it('a subtree path covers all parameters that start with it', () => {
    fc.assert(
      fc.property(
        fc.array(segmentArb, { minLength: 1, maxLength: 3 }),
        fc.array(segmentArb, { minLength: 1, maxLength: 3 }),
        (prefixSegments, suffixSegments) => {
          const subtreePath = prefixSegments.join('.') + '.'
          const paramPath = prefixSegments.join('.') + '.' + suffixSegments.join('.')
          const result = isParameterCoveredByInventory(paramPath, [{ path: subtreePath }])
          expect(result).toBe(true)
        }
      ),
      { numRuns: 200 }
    )
  })

  it('a subtree path does NOT cover parameters that do not start with it', () => {
    fc.assert(
      fc.property(
        fc.array(segmentArb, { minLength: 1, maxLength: 3 }),
        fc.array(segmentArb, { minLength: 1, maxLength: 3 }),
        segmentArb,
        (prefixSegments, suffixSegments, differentFirst) => {
          const subtreePath = prefixSegments.join('.') + '.'
          // Build a param that does NOT start with the subtree path
          // by using a different first segment
          const altFirst = differentFirst + 'X' // ensure it differs
          const paramPath = altFirst + '.' + suffixSegments.join('.')

          // Only assert when the param truly doesn't start with the subtree
          fc.pre(!paramPath.startsWith(subtreePath))

          const result = isParameterCoveredByInventory(paramPath, [{ path: subtreePath }])
          expect(result).toBe(false)
        }
      ),
      { numRuns: 200 }
    )
  })

  it('an exact path (no trailing dot) only matches the exact same string', () => {
    fc.assert(
      fc.property(tr069PathArb, tr069PathArb, (exactPath, otherPath) => {
        // exactPath has no trailing dot, so it's an exact match inventory path
        fc.pre(!exactPath.endsWith('.'))
        const result = isParameterCoveredByInventory(otherPath, [{ path: exactPath }])
        if (otherPath === exactPath) {
          expect(result).toBe(true)
        } else {
          expect(result).toBe(false)
        }
      }),
      { numRuns: 200 }
    )
  })

  it('empty inventory paths array means never covered', () => {
    fc.assert(
      fc.property(tr069PathArb, (paramPath) => {
        const result = isParameterCoveredByInventory(paramPath, [])
        expect(result).toBe(false)
      }),
      { numRuns: 200 }
    )
  })
})