import { describe, expect, it } from 'vitest'
import {
  mergeQueryLogs,
  mergeSettled,
  mergeStats,
  mergeTop,
  mergeTopResponses,
  type ChartData,
  type DashboardStats,
  type QueryLogEntry,
  type QueryLogPage,
  type Settled,
} from './merge.ts'

/* Fixtures in the shape of `dashboard/stats/get` (see dev/mock-api.mjs). */
function stats(over: Partial<Record<string, number>> = {}): Record<string, number> {
  return {
    totalQueries: 100, totalNoError: 90, totalServerFailure: 1, totalNxDomain: 5, totalRefused: 4,
    totalAuthoritative: 10, totalRecursive: 30, totalCached: 50, totalBlocked: 8, totalDropped: 2,
    totalClients: 12, zones: 3, cachedEntries: 400, allowedZones: 1, blockedZones: 2, allowListZones: 1,
    blockListZones: 1000, ...over,
  } as Record<string, number>
}

function response(over: Partial<DashboardStats> = {}): DashboardStats {
  return {
    stats: stats(),
    mainChartData: {
      labelFormat: 'HH:mm',
      labels: ['2026-01-01T10:00:00Z', '2026-01-01T11:00:00Z'],
      datasets: [{ label: 'Total', data: [40, 60] }, { label: 'Blocked', data: [3, 5] }],
    },
    queryResponseChartData: {
      labels: ['Authoritative', 'Recursive', 'Cached'],
      datasets: [{ label: 'Total', data: [10, 30, 50], backgroundColor: ['#111', '#222', '#333'] }],
    },
    queryTypeChartData: { labels: ['A', 'AAAA'], datasets: [{ label: 'Total', data: [70, 30], backgroundColor: [] }] },
    protocolTypeChartData: { labels: ['UDP', 'TCP'], datasets: [{ label: 'Total', data: [90, 10], backgroundColor: [] }] },
    topClients: [{ name: '10.0.0.1', domain: 'a.lan', hits: 50 }],
    topDomains: [{ name: 'example.com', hits: 30 }],
    topBlockedDomains: [{ name: 'ads.example.com', hits: 8 }],
    ...over,
  }
}

describe('mergeStats counters', () => {
  it('sums every numeric field of stats', () => {
    const merged = mergeStats([response(), response({ stats: stats({ totalQueries: 250, zones: 7 }) })])
    expect(merged.stats.totalQueries).toBe(350)
    expect(merged.stats.totalNoError).toBe(180)
    expect(merged.stats.zones).toBe(10)
    expect(merged.stats.blockListZones).toBe(2000)
    expect(Object.keys(merged.stats)).toEqual(Object.keys(stats()))
  })

  it('sums what each server holds: zones, cache, allowed, blocked and the two lists', () => {
    const a = response({ stats: stats({ zones: 3, cachedEntries: 400, allowedZones: 1, blockedZones: 2, allowListZones: 1, blockListZones: 1000 }) })
    const b = response({ stats: stats({ zones: 5, cachedEntries: 50, allowedZones: 4, blockedZones: 6, allowListZones: 2, blockListZones: 10 }) })
    const merged = mergeStats([a, b])
    expect(merged.stats).toMatchObject({ zones: 8, cachedEntries: 450, allowedZones: 5, blockedZones: 8, allowListZones: 3, blockListZones: 1010 })
  })

  it('counts a numeric string, and a server that left a field out as none', () => {
    const a = response({ stats: { ...stats(), zones: '4' as unknown as number } })
    const b = response({ stats: { totalQueries: 1 } })
    const merged = mergeStats([a, b])
    expect(merged.stats.zones).toBe(4)
    expect(merged.stats.allowedZones).toBe(1)
    expect(merged.stats.totalQueries).toBe(101)
    expect(mergeStats([b]).stats.blockListZones).toBe(0)
  })

  it('returns a single response with the same numbers', () => {
    const merged = mergeStats([response()])
    expect(merged.stats).toEqual(stats())
    expect(merged.mainChartData?.datasets[0].data).toEqual([40, 60])
  })

  it('throws on nothing to merge', () => {
    expect(() => mergeStats([])).toThrow()
  })

  it('does not mutate its inputs', () => {
    const a = response()
    const b = response()
    const before = JSON.stringify([a, b])
    mergeStats([a, b])
    expect(JSON.stringify([a, b])).toBe(before)
  })
})

describe('mergeStats main chart', () => {
  it('sums the values of equal labels per dataset', () => {
    const merged = mergeStats([response(), response()])
    expect(merged.mainChartData?.labels).toEqual(['2026-01-01T10:00:00Z', '2026-01-01T11:00:00Z'])
    expect(merged.mainChartData?.datasets).toEqual([
      { label: 'Total', data: [80, 120] },
      { label: 'Blocked', data: [6, 10] },
    ])
    expect(merged.mainChartData?.labelFormat).toBe('HH:mm')
  })

  it('aligns differing label sets by label, missing points count as 0, order stays chronological', () => {
    const a: ChartData = { labels: ['t1', 't2', 't4'], datasets: [{ label: 'Total', data: [1, 2, 4] }] }
    const b: ChartData = { labels: ['t2', 't3', 't4', 't5'], datasets: [{ label: 'Total', data: [20, 30, 40, 50] }] }
    const merged = mergeStats([response({ mainChartData: a }), response({ mainChartData: b })])
    expect(merged.mainChartData?.labels).toEqual(['t1', 't2', 't3', 't4', 't5'])
    expect(merged.mainChartData?.datasets[0].data).toEqual([1, 22, 30, 44, 50])
  })

  it('slips earlier labels of a later server before the first shared label', () => {
    const a: ChartData = { labels: ['t3', 't4'], datasets: [{ label: 'Total', data: [3, 4] }] }
    const b: ChartData = { labels: ['t1', 't2', 't3'], datasets: [{ label: 'Total', data: [10, 20, 30] }] }
    const merged = mergeStats([response({ mainChartData: a }), response({ mainChartData: b })])
    expect(merged.mainChartData?.labels).toEqual(['t1', 't2', 't3', 't4'])
    expect(merged.mainChartData?.datasets[0].data).toEqual([10, 20, 33, 4])
  })

  it('matches datasets by label, not by position', () => {
    const a: ChartData = {
      labels: ['t1'],
      datasets: [{ label: 'Total', data: [5] }, { label: 'Blocked', data: [1] }],
    }
    const b: ChartData = {
      labels: ['t1'],
      datasets: [{ label: 'Blocked', data: [10] }, { label: 'Cached', data: [7] }, { label: 'Total', data: [50] }],
    }
    const merged = mergeStats([response({ mainChartData: a }), response({ mainChartData: b })])
    expect(merged.mainChartData?.datasets).toEqual([
      { label: 'Total', data: [55] },
      { label: 'Blocked', data: [11] },
      { label: 'Cached', data: [7] },
    ])
  })

  it('keeps a dataset that only one server has, zero where the other labels are', () => {
    const a: ChartData = { labels: ['t1'], datasets: [{ label: 'Total', data: [5] }] }
    const b: ChartData = { labels: ['t2'], datasets: [{ label: 'Cached', data: [7] }] }
    const merged = mergeStats([response({ mainChartData: a }), response({ mainChartData: b })])
    expect(merged.mainChartData?.labels).toEqual(['t1', 't2'])
    expect(merged.mainChartData?.datasets).toEqual([
      { label: 'Total', data: [5, 0] },
      { label: 'Cached', data: [0, 7] },
    ])
  })

  it('keeps the other properties of the first dataset that has them', () => {
    const a: ChartData = { labels: ['t1'], datasets: [{ label: 'Total', data: [1], backgroundColor: '#aaa' }] }
    const b: ChartData = { labels: ['t1'], datasets: [{ label: 'Total', data: [2], backgroundColor: '#bbb' }] }
    const merged = mergeStats([response({ mainChartData: a }), response({ mainChartData: b })])
    expect(merged.mainChartData?.datasets[0]).toEqual({ label: 'Total', data: [3], backgroundColor: '#aaa' })
  })

  it('survives a server without a main chart', () => {
    const merged = mergeStats([response({ mainChartData: undefined }), response()])
    expect(merged.mainChartData?.datasets[0].data).toEqual([40, 60])
  })
})

describe('mergeStats breakdown charts', () => {
  it('sums values per label and keeps the colours of the first server', () => {
    const merged = mergeStats([response(), response()])
    expect(merged.queryResponseChartData).toEqual({
      labels: ['Authoritative', 'Recursive', 'Cached'],
      datasets: [{ label: 'Total', data: [20, 60, 100], backgroundColor: ['#111', '#222', '#333'] }],
    })
    expect(merged.queryTypeChartData?.datasets[0].data).toEqual([140, 60])
    expect(merged.protocolTypeChartData?.datasets[0].data).toEqual([180, 20])
  })

  it('keeps the label order of the first server and appends new labels', () => {
    const a: ChartData = { labels: ['A', 'AAAA'], datasets: [{ label: 'Total', data: [1, 2] }] }
    const b: ChartData = { labels: ['TXT', 'AAAA', 'A', 'MX'], datasets: [{ label: 'Total', data: [10, 20, 30, 40] }] }
    const merged = mergeStats([response({ queryTypeChartData: a }), response({ queryTypeChartData: b })])
    expect(merged.queryTypeChartData?.labels).toEqual(['A', 'AAAA', 'TXT', 'MX'])
    expect(merged.queryTypeChartData?.datasets[0].data).toEqual([31, 22, 10, 40])
  })
})

describe('mergeStats top lists', () => {
  it('merges the three top lists inside the stats', () => {
    const a = response({
      topClients: [{ name: '10.0.0.1', domain: '', hits: 50 }, { name: '10.0.0.2', hits: 10, rateLimited: true }],
      topDomains: [{ name: 'a.com', hits: 5 }],
    })
    const b = response({
      topClients: [{ name: '10.0.0.1', domain: 'host.lan', hits: 25 }],
      topDomains: [{ name: 'b.com', hits: 9 }],
      topBlockedDomains: [{ name: 'ads.example.com', hits: 2 }],
    })
    const merged = mergeStats([a, b])
    expect(merged.topClients).toEqual([
      { name: '10.0.0.1', domain: 'host.lan', hits: 75 },
      { name: '10.0.0.2', hits: 10, rateLimited: true },
    ])
    // The default limit is the longest input list (1 here).
    expect(merged.topDomains).toEqual([{ name: 'b.com', hits: 9 }])
    expect(merged.topBlockedDomains).toEqual([{ name: 'ads.example.com', hits: 10 }])
  })
})

describe('mergeTop', () => {
  it('sums hits by name, sorts by hits and cuts to the longest input by default', () => {
    const a = [{ name: 'a', hits: 10 }, { name: 'b', hits: 5 }, { name: 'c', hits: 1 }]
    const b = [{ name: 'c', hits: 20 }, { name: 'd', hits: 7 }]
    expect(mergeTop([a, b])).toEqual([
      { name: 'c', hits: 21 },
      { name: 'a', hits: 10 },
      { name: 'd', hits: 7 },
    ])
  })

  it('cuts to an explicit limit', () => {
    const a = [{ name: 'a', hits: 10 }, { name: 'b', hits: 9 }]
    const b = [{ name: 'c', hits: 8 }, { name: 'd', hits: 7 }]
    expect(mergeTop([a, b], 3).map((e) => e.name)).toEqual(['a', 'b', 'c'])
    expect(mergeTop([a, b], 0)).toEqual([])
  })

  it('breaks ties by name ascending', () => {
    const a = [{ name: 'zeta', hits: 5 }, { name: 'alpha', hits: 5 }]
    const b = [{ name: 'mid', hits: 5 }]
    expect(mergeTop([a, b], 10).map((e) => e.name)).toEqual(['alpha', 'mid', 'zeta'])
  })

  it('keeps the first non-empty domain and ORs rateLimited', () => {
    const a = [{ name: 'c1', domain: '', hits: 1 }]
    const b = [{ name: 'c1', domain: 'first.lan', hits: 1, rateLimited: true }]
    const c = [{ name: 'c1', domain: 'second.lan', hits: 1 }]
    expect(mergeTop([a, b, c])).toEqual([{ name: 'c1', domain: 'first.lan', hits: 3, rateLimited: true }])
  })

  it('ignores missing lists and does not mutate the inputs', () => {
    const a = [{ name: 'a', hits: 1 }]
    expect(mergeTop([a, undefined, a])).toEqual([{ name: 'a', hits: 2 }])
    expect(a).toEqual([{ name: 'a', hits: 1 }])
    expect(mergeTop([])).toEqual([])
  })
})

describe('mergeTopResponses', () => {
  it('merges the getTop shape under the key the servers used', () => {
    const merged = mergeTopResponses([
      { topClients: [{ name: 'x', hits: 3 }] },
      { topClients: [{ name: 'x', hits: 4 }, { name: 'y', hits: 1 }] },
    ], 1)
    expect(merged).toEqual({ topClients: [{ name: 'x', hits: 7 }] })
  })

  it('works for domains and blocked domains', () => {
    expect(mergeTopResponses([{ topDomains: [{ name: 'a', hits: 1 }] }, { topDomains: [{ name: 'a', hits: 1 }] }]))
      .toEqual({ topDomains: [{ name: 'a', hits: 2 }] })
    expect(mergeTopResponses([{ topBlockedDomains: [{ name: 'b', hits: 1 }] }]))
      .toEqual({ topBlockedDomains: [{ name: 'b', hits: 1 }] })
  })
})

/* Fixtures in the shape of `logs/query` (see dev/mock-api.mjs). */
function entry(timestamp: string, qname: string): QueryLogEntry {
  return {
    rowNumber: 1, timestamp, clientIpAddress: '192.168.10.14', protocol: 'Udp', responseType: 'Cached',
    responseRtt: 1.5, rcode: 'NoError', qname, qtype: 'A', qclass: 'IN', answer: '1.1.1.1',
  }
}

function page(entries: QueryLogEntry[], totalEntries = entries.length): QueryLogPage {
  return { pageNumber: 1, totalPages: 1, totalEntries, entries }
}

describe('mergeQueryLogs', () => {
  const dns = page([entry('2026-01-01T10:00:03Z', 'a.com'), entry('2026-01-01T10:00:01Z', 'c.com')])
  const ndns = page([entry('2026-01-01T10:00:04Z', 'b.com'), entry('2026-01-01T10:00:02Z', 'd.com')])
  const pages = [{ node: 'dns', page: dns }, { node: 'ndns', page: ndns }]

  it('sorts newest first by default and tags each entry with its server', () => {
    const merged = mergeQueryLogs(pages, { pageNumber: 1, entriesPerPage: 25 })
    expect(merged.entries.map((e) => e.qname)).toEqual(['b.com', 'a.com', 'd.com', 'c.com'])
    expect(merged.entries.map((e) => e.node)).toEqual(['ndns', 'dns', 'ndns', 'dns'])
    expect(merged.entries[0]).toMatchObject({ clientIpAddress: '192.168.10.14', answer: '1.1.1.1', responseRtt: 1.5 })
  })

  it('sorts oldest first when descending is false', () => {
    const merged = mergeQueryLogs(pages, { pageNumber: 1, entriesPerPage: 25, descending: false })
    expect(merged.entries.map((e) => e.qname)).toEqual(['c.com', 'd.com', 'a.com', 'b.com'])
  })

  it('renumbers rows from 1 and sums the totals', () => {
    const merged = mergeQueryLogs(
      [{ node: 'dns', page: page(dns.entries, 120) }, { node: 'ndns', page: page(ndns.entries, 31) }],
      { pageNumber: 1, entriesPerPage: 25 },
    )
    expect(merged.entries.map((e) => e.rowNumber)).toEqual([1, 2, 3, 4])
    expect(merged.totalEntries).toBe(151)
    expect(merged.totalPages).toBe(7)
    expect(merged.pageNumber).toBe(1)
  })

  it('cuts page N from the merged head of every server and numbers it from its offset', () => {
    // Each server sent its first 2 x 2 entries; page 2 is the 3rd and 4th of the merged list.
    const merged = mergeQueryLogs(pages, { pageNumber: 2, entriesPerPage: 2 })
    expect(merged.pageNumber).toBe(2)
    expect(merged.entries.map((e) => e.qname)).toEqual(['d.com', 'c.com'])
    expect(merged.entries.map((e) => e.rowNumber)).toEqual([3, 4])
  })

  it('a page past the end is empty', () => {
    expect(mergeQueryLogs(pages, { pageNumber: 3, entriesPerPage: 2 }).entries).toEqual([])
  })

  it('cuts to entriesPerPage', () => {
    const merged = mergeQueryLogs(pages, { pageNumber: 1, entriesPerPage: 3 })
    expect(merged.entries.map((e) => e.qname)).toEqual(['b.com', 'a.com', 'd.com'])
    expect(merged.totalEntries).toBe(4)
    expect(merged.totalPages).toBe(2)
  })

  it('keeps server order for equal timestamps', () => {
    const same = [
      { node: 'dns', page: page([entry('2026-01-01T10:00:00Z', 'x.com')]) },
      { node: 'ndns', page: page([entry('2026-01-01T10:00:00Z', 'y.com')]) },
    ]
    expect(mergeQueryLogs(same, { pageNumber: 1, entriesPerPage: 10 }).entries.map((e) => e.node)).toEqual(['dns', 'ndns'])
  })

  it('handles empty pages', () => {
    const merged = mergeQueryLogs([{ node: 'dns', page: page([]) }], { pageNumber: 1, entriesPerPage: 25 })
    expect(merged).toEqual({ pageNumber: 1, totalPages: 0, totalEntries: 0, entries: [] })
  })

  it('does not mutate the input entries', () => {
    mergeQueryLogs(pages, { pageNumber: 2, entriesPerPage: 2 })
    expect(dns.entries[0].node).toBeUndefined()
    expect(dns.entries[0].rowNumber).toBe(1)
  })
})

describe('mergeSettled', () => {
  it('returns the data of the servers that answered', () => {
    const results: Settled<number>[] = [{ node: 'dns', ok: true, data: 1 }, { node: 'ndns', ok: true, data: 2 }]
    expect(mergeSettled(results)).toEqual({ data: [1, 2], warnings: [] })
  })

  it('warns about an unreachable server and keeps the other one', () => {
    const results: Settled<number>[] = [
      { node: 'dns', ok: true, data: 1 },
      { node: 'ndns', ok: false, error: 'timeout' },
    ]
    expect(mergeSettled(results)).toEqual({ data: [1], warnings: ['ndns: timeout'] })
  })

  it('throws naming every server when all failed', () => {
    const results: Settled<number>[] = [
      { node: 'dns', ok: false, error: 'refused' },
      { node: 'ndns', ok: false, error: 'timeout' },
    ]
    expect(() => mergeSettled(results)).toThrow(/dns: refused.*ndns: timeout/)
  })
})