import { describe, it, expect } from 'vitest'
import fc from 'fast-check'

// --- Pure logic extracted from InspectorPanel.vue ---

/**
 * Formats XML with 2-space indentation (same logic as InspectorPanel.vue prettyPrintXml).
 */
function prettyPrintXml(xml: string): string {
  let formatted = ''
  let indent = 0
  const lines = xml
    .replace(/>\s*</g, '>\n<')
    .replace(/\n\s*\n/g, '\n')
    .split('\n')

  for (const rawLine of lines) {
    const line = rawLine.trim()
    if (!line) continue

    // Closing tag
    if (line.startsWith('</')) {
      indent = Math.max(0, indent - 1)
      formatted += ' '.repeat(indent * 2) + line + '\n'
    }
    // Self-closing tag or processing instruction
    else if (line.endsWith('/>') || line.startsWith('<?')) {
      formatted += ' '.repeat(indent * 2) + line + '\n'
    }
    // Opening tag (not self-closing)
    else if (line.startsWith('<') && !line.startsWith('</') && line.includes('>')) {
      formatted += ' '.repeat(indent * 2) + line + '\n'
      // Only increase indent if this is a pure opening tag (not self-closing and not containing content + close)
      const tagContent = line.replace(/<[^>]*>/g, '').trim()
      const closeTagMatch = line.match(/<\/[^>]+>/)
      if (!closeTagMatch && !line.endsWith('/>') && tagContent === '') {
        indent++
      }
    } else {
      formatted += ' '.repeat(indent * 2) + line + '\n'
    }
  }

  return formatted.trim()
}

/**
 * Formats XML content with graceful fallback (same logic as InspectorPanel.vue formatXml).
 */
function formatXml(xml: string): string {
  if (!xml || xml.trim() === '') return ''

  try {
    return prettyPrintXml(xml)
  } catch {
    return xml
  }
}

/**
 * Generates the header text for the Inspector Panel (same logic as InspectorPanel.vue headerText computed).
 */
function generateHeaderText(cwmpMethod: string, direction: string): string {
  return `${cwmpMethod} — ${direction}`
}

// --- Arbitraries ---

const PBT_NUM_RUNS = 100

const arbDirection = fc.constantFrom('CPE→ACS' as const, 'ACS→CPE' as const)

const arbCwmpMethod = fc.constantFrom(
  'Inform',
  'InformResponse',
  'GetParameterValues',
  'GetParameterValuesResponse',
  'SetParameterValues',
  'SetParameterValuesResponse',
  'AddObject',
  'AddObjectResponse',
  'DeleteObject',
  'DeleteObjectResponse',
  'Download',
  'DownloadResponse',
  'Upload',
  'Reboot',
  'FactoryReset',
  'Fault',
  'Empty',
  'Unknown'
)

/**
 * Generate a random XML tag name (valid XML element name: letters, digits, hyphens, dots, underscores, colons).
 */
const arbTagName = fc
  .tuple(
    fc.constantFrom(...'abcdefghijklmnopqrstuvwxyz'.split('')),
    fc.array(
      fc.constantFrom(...'abcdefghijklmnopqrstuvwxyz0123456789-_:.'.split('')),
      { minLength: 1, maxLength: 15 }
    )
  )
  .map(([first, rest]) => first + rest.join(''))

/**
 * Generate safe text content (no XML special chars).
 */
const arbSafeText = fc
  .string({ minLength: 1, maxLength: 30 })
  .map((s) => s.replace(/[<>&"']/g, 'x'))

/**
 * Generate a simple nested XML structure with 1-3 levels of nesting.
 * Ensures valid well-formed XML that the prettyPrintXml can format.
 */
const arbSimpleXml = fc
  .tuple(
    arbTagName,
    fc.array(
      fc.tuple(arbTagName, arbSafeText),
      { minLength: 1, maxLength: 5 }
    )
  )
  .map(([root, children]) => {
    const childXml = children
      .map(([tag, text]) => `<${tag}>${text}</${tag}>`)
      .join('')
    return `<${root}>${childXml}</${root}>`
  })

/**
 * Generate a SOAP envelope-like XML structure with cwmp namespace (realistic test data).
 */
const arbSoapXml = fc
  .tuple(
    arbCwmpMethod,
    fc.array(
      fc.tuple(arbTagName, arbSafeText),
      { minLength: 0, maxLength: 4 }
    )
  )
  .map(([method, params]) => {
    const paramXml = params
      .map(([tag, text]) => `<${tag}>${text}</${tag}>`)
      .join('')
    const body = paramXml
      ? `<cwmp:${method}>${paramXml}</cwmp:${method}>`
      : `<cwmp:${method}/>`
    return `<soap-env:Envelope xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/" xmlns:cwmp="urn:dslforum-org:cwmp-1-0"><soap-env:Header/><soap-env:Body>${body}</soap-env:Body></soap-env:Envelope>`
  })

/**
 * Arbitrary for non-empty rawXml content (either simple or SOAP-like).
 */
const arbNonEmptyXml = fc.oneof(arbSimpleXml, arbSoapXml)

/**
 * Generate a random CwmpExchange object with non-empty rawXml.
 */
const arbCwmpExchange = fc.record({
  deviceId: fc
    .array(fc.constantFrom(...'abcdefghijklmnopqrstuvwxyz0123456789'.split('')), {
      minLength: 5,
      maxLength: 20,
    })
    .map((chars) => chars.join('')),
  direction: arbDirection,
  timestamp: fc
    .integer({ min: 1577836800000, max: 1924905600000 })
    .map((ms) => new Date(ms).toISOString()),
  sessionId: fc
    .tuple(
      fc.ipV4(),
      fc.integer({ min: 1024, max: 65535 }),
      fc.ipV4(),
      fc.integer({ min: 1, max: 65535 })
    )
    .map(([ip1, port1, ip2, port2]) => `${ip1}:${port1}->${ip2}:${port2}`),
  cwmpMethod: arbCwmpMethod,
  rawXml: arbNonEmptyXml,
  sequenceNumber: fc.integer({ min: 1, max: 100_000 }),
})

// ─── Property Tests ──────────────────────────────────────────────────────────

/**
 * Property 12: Inspector Panel Display on Selection
 * Validates: Requirements 5.1, 5.2
 *
 * For any selected CWMP message with non-empty rawXml, the Inspector Panel SHALL
 * display the XML formatted with 2-space indentation AND a header showing the
 * cwmpMethod name and direction ("CPE→ACS" or "ACS→CPE").
 */
describe('Property 12: Inspector Panel Display on Selection', () => {
  describe('Formatted XML uses 2-space indentation', () => {
    it('all indented lines in formatted XML start with multiples of 2 spaces', () => {
      fc.assert(
        fc.property(arbCwmpExchange, (exchange) => {
          const formatted = formatXml(exchange.rawXml)

          // The formatted output should not be empty for non-empty XML
          expect(formatted.length).toBeGreaterThan(0)

          // Every line should start with 0 or more groups of exactly 2 spaces
          const lines = formatted.split('\n')
          for (const line of lines) {
            if (line.trim() === '') continue

            // Count leading spaces
            const leadingSpaces = line.match(/^( *)/)?.[1]?.length ?? 0

            // Leading spaces must be a multiple of 2 (0, 2, 4, 6, ...)
            expect(leadingSpaces % 2).toBe(0)
          }
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })

    it('formatted XML preserves all original tag content (no data loss)', () => {
      fc.assert(
        fc.property(arbCwmpExchange, (exchange) => {
          const formatted = formatXml(exchange.rawXml)

          // Strip all whitespace from both to compare content
          const originalNoWs = exchange.rawXml.replace(/\s+/g, '')
          const formattedNoWs = formatted.replace(/\s+/g, '')

          expect(formattedNoWs).toBe(originalNoWs)
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })

    it('nested XML produces increasing indentation levels', () => {
      fc.assert(
        fc.property(arbSoapXml, (xml) => {
          const formatted = formatXml(xml)
          const lines = formatted.split('\n').filter((l) => l.trim() !== '')

          // For multi-line XML, at least some lines should have indentation > 0
          if (lines.length > 2) {
            const maxIndent = Math.max(
              ...lines.map((l) => (l.match(/^( *)/)?.[1]?.length ?? 0))
            )
            // Nested XML should produce at least 2-space indentation somewhere
            expect(maxIndent).toBeGreaterThanOrEqual(2)
          }
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })

    it('self-closing tags do not increase indentation for following lines', () => {
      fc.assert(
        fc.property(arbTagName, arbTagName, (root, child) => {
          // Build XML with a self-closing tag followed by a normal element
          const xml = `<${root}><${child}/><other>text</other></${root}>`
          const formatted = formatXml(xml)
          const lines = formatted.split('\n').filter((l) => l.trim() !== '')

          // The self-closing tag and the next element should be at the same indentation level
          if (lines.length >= 3) {
            const selfClosingLine = lines.find((l) => l.trim().endsWith('/>'))
            const nextLine = selfClosingLine
              ? lines[lines.indexOf(selfClosingLine) + 1]
              : undefined

            if (selfClosingLine && nextLine && !nextLine.trim().startsWith('</')) {
              const selfClosingIndent = selfClosingLine.match(/^( *)/)?.[1]?.length ?? 0
              const nextIndent = nextLine.match(/^( *)/)?.[1]?.length ?? 0
              expect(nextIndent).toBe(selfClosingIndent)
            }
          }
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })
  })

  describe('Header displays cwmpMethod and direction', () => {
    it('header text contains both cwmpMethod and direction for any exchange', () => {
      fc.assert(
        fc.property(arbCwmpExchange, (exchange) => {
          const header = generateHeaderText(exchange.cwmpMethod, exchange.direction)

          // Header must include the cwmpMethod
          expect(header).toContain(exchange.cwmpMethod)

          // Header must include the direction
          expect(header).toContain(exchange.direction)
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })

    it('header text follows format "cwmpMethod — direction"', () => {
      fc.assert(
        fc.property(arbCwmpMethod, arbDirection, (method, direction) => {
          const header = generateHeaderText(method, direction)

          // Exact format: "method — direction"
          expect(header).toBe(`${method} — ${direction}`)
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })

    it('header always contains the em dash separator', () => {
      fc.assert(
        fc.property(arbCwmpExchange, (exchange) => {
          const header = generateHeaderText(exchange.cwmpMethod, exchange.direction)

          // The em dash separator must be present
          expect(header).toContain(' — ')
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })

    it('header direction is always one of the two valid values', () => {
      fc.assert(
        fc.property(arbCwmpExchange, (exchange) => {
          const header = generateHeaderText(exchange.cwmpMethod, exchange.direction)

          // Direction must be one of the two valid directions
          const containsCpeToAcs = header.includes('CPE→ACS')
          const containsAcsToCpe = header.includes('ACS→CPE')

          expect(containsCpeToAcs || containsAcsToCpe).toBe(true)
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })
  })

  describe('Combined: formatted XML + header for random exchanges', () => {
    it('for any exchange with non-empty rawXml, both formatted output and header are correctly generated', () => {
      fc.assert(
        fc.property(arbCwmpExchange, (exchange) => {
          // --- Verify formatted XML ---
          const formatted = formatXml(exchange.rawXml)

          // Formatted output is non-empty
          expect(formatted.length).toBeGreaterThan(0)

          // All lines use 2-space indentation multiples
          const lines = formatted.split('\n')
          for (const line of lines) {
            if (line.trim() === '') continue
            const leadingSpaces = line.match(/^( *)/)?.[1]?.length ?? 0
            expect(leadingSpaces % 2).toBe(0)
          }

          // --- Verify header ---
          const header = generateHeaderText(exchange.cwmpMethod, exchange.direction)

          // Header includes cwmpMethod
          expect(header).toContain(exchange.cwmpMethod)

          // Header includes direction
          expect(header).toContain(exchange.direction)
        }),
        { numRuns: PBT_NUM_RUNS }
      )
    })
  })
})