import { afterEach, beforeEach, describe, expect, it } from 'vitest'
import {
  createFolder,
  createHost,
  deleteNode,
  getConnectionTree,
  getHost,
  isDescendantOf,
  listHosts,
  moveNode,
  renameFolder,
  updateHost,
} from '../src/main/db/repositories/connections'
import type { HostInput } from '../src/shared/ipc-schemas'
import { createTempDb, type TempDb } from './helpers'

let temp: TempDb

beforeEach(() => {
  temp = createTempDb()
})

afterEach(() => {
  temp.cleanup()
})

function hostInput(overrides: Partial<HostInput> = {}): HostInput {
  return {
    parentId: null,
    label: 'web-01',
    hostname: '10.0.1.5',
    port: 22,
    username: 'root',
    authType: 'password',
    keyPath: null,
    color: null,
    ...overrides,
  }
}

function addHost(parentId: number | null, label: string): number {
  return createHost(temp.db, hostInput({ parentId, label }))
}

/** Labels of a layer, in tree order, for compact assertions. */
function layerNames(nodes: ReturnType<typeof getConnectionTree>): string[] {
  return nodes.map((n) => (n.kind === 'folder' ? n.name : n.label))
}

describe('creating nodes', () => {
  it('creates top-level folders and nests them', () => {
    const prod = createFolder(temp.db, null, 'prod')
    const web = createFolder(temp.db, prod, 'web')

    const tree = getConnectionTree(temp.db)
    expect(layerNames(tree)).toEqual(['prod'])

    const root = tree[0]
    expect(root.kind).toBe('folder')
    if (root.kind === 'folder') {
      expect(root.id).toBe(prod)
      expect(layerNames(root.children)).toEqual(['web'])
      expect(root.children[0].id).toBe(web)
    }
  })

  it('gives folders and hosts ids from one shared sequence', () => {
    // The point of the interleaved tree: a folder and a host can never collide
    // on an id, so a node id is a complete identity.
    const folder = createFolder(temp.db, null, 'f')
    const host = addHost(null, 'h')

    expect(folder).not.toBe(host)
    expect(new Set([folder, host]).size).toBe(2)
  })

  it('stores host attributes', () => {
    const id = createHost(
      temp.db,
      hostInput({ label: 'db', hostname: '10.0.2.10', port: 5432, username: 'postgres' }),
    )

    const host = getHost(temp.db, id)
    expect(host).toMatchObject({
      label: 'db',
      hostname: '10.0.2.10',
      port: 5432,
      username: 'postgres',
      parentId: null,
    })
  })

  it('appends new nodes to the end of their layer', () => {
    const first = addHost(null, 'first')
    const second = addHost(null, 'second')

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['first', 'second'])
    expect(getHost(temp.db, second)?.sortOrder).toBeGreaterThan(
      getHost(temp.db, first)?.sortOrder ?? 0,
    )
  })
})

describe('interleaving folders and hosts', () => {
  it('renders them in one order rather than grouping by kind', () => {
    // The whole point of the schema change. Before it, every folder came before
    // every host, because the two sort_order sequences were not comparable.
    const folder = createFolder(temp.db, null, 'folder')
    const host = addHost(null, 'host')

    // Drop the host ahead of the folder.
    moveNode(temp.db, host, null, null, folder)

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['host', 'folder'])
  })

  it('allows a host between two folders', () => {
    // Not expressible at all before the interleaving — the two sequences had no
    // common scale.
    const a = createFolder(temp.db, null, 'a')
    const b = createFolder(temp.db, null, 'b')
    const host = addHost(null, 'middle')

    moveNode(temp.db, host, null, a, b)

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['a', 'middle', 'b'])
  })

  it('allows a folder between two hosts', () => {
    const h1 = addHost(null, 'h1')
    const h2 = addHost(null, 'h2')
    const folder = createFolder(temp.db, null, 'middle')

    moveNode(temp.db, folder, null, h1, h2)

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['h1', 'middle', 'h2'])
  })

  it('keeps a layer strictly ordered through many midpoint inserts', () => {
    const anchorLeft = createFolder(temp.db, null, 'left')
    const anchorRight = createFolder(temp.db, null, 'right')

    // Each insert goes into the gap immediately right of the previous one, so
    // the interval halves every time — the precision-exhaustion scenario the
    // REAL ordering trades for never renumbering siblings.
    let previous = anchorLeft
    for (let i = 0; i < 30; i++) {
      const id = addHost(null, `mid-${i}`)
      moveNode(temp.db, id, null, previous, anchorRight)
      previous = id
    }

    const orders = getConnectionTree(temp.db).map((n) => n.sortOrder)
    expect(orders).toHaveLength(32)
    expect(new Set(orders).size).toBe(orders.length)
  })
})

describe('moving nodes', () => {
  it('reparents a host into a folder', () => {
    const folder = createFolder(temp.db, null, 'group')
    const host = addHost(null, 'roamer')

    moveNode(temp.db, host, folder)

    const tree = getConnectionTree(temp.db)
    expect(tree).toHaveLength(1)
    if (tree[0].kind === 'folder') {
      expect(layerNames(tree[0].children)).toEqual(['roamer'])
    }
  })

  it('moves a node back out to the root layer', () => {
    const folder = createFolder(temp.db, null, 'group')
    const host = createHost(temp.db, hostInput({ parentId: folder, label: 'inside' }))

    moveNode(temp.db, host, null)

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['group', 'inside'])
  })

  it('refuses to make a node its own parent', () => {
    const folder = createFolder(temp.db, null, 'f')
    expect(() => moveNode(temp.db, folder, folder)).toThrow(/own parent/)
  })

  it('refuses to move a folder into its own descendant', () => {
    // Without this the subtree detaches from every root and disappears from the
    // UI while its rows remain.
    const a = createFolder(temp.db, null, 'a')
    const b = createFolder(temp.db, a, 'b')
    const c = createFolder(temp.db, b, 'c')

    expect(() => moveNode(temp.db, a, b)).toThrow(/descendant/)
    expect(() => moveNode(temp.db, a, c)).toThrow(/descendant/)
  })

  it('identifies descendants correctly', () => {
    const a = createFolder(temp.db, null, 'a')
    const b = createFolder(temp.db, a, 'b')
    const unrelated = createFolder(temp.db, null, 'unrelated')

    expect(isDescendantOf(temp.db, b, a)).toBe(true)
    expect(isDescendantOf(temp.db, a, b)).toBe(false)
    expect(isDescendantOf(temp.db, unrelated, a)).toBe(false)
  })
})

describe('updating and deleting', () => {
  it('renames a folder', () => {
    const id = createFolder(temp.db, null, 'old')
    renameFolder(temp.db, id, 'new')

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['new'])
  })

  it('updates a host without moving it', () => {
    const folder = createFolder(temp.db, null, 'group')
    const host = createHost(temp.db, hostInput({ parentId: folder, label: 'before' }))
    const sortBefore = getHost(temp.db, host)?.sortOrder

    updateHost(temp.db, host, hostInput({ parentId: folder, label: 'after', port: 2222 }))

    const record = getHost(temp.db, host)
    expect(record?.label).toBe('after')
    expect(record?.port).toBe(2222)
    // An edit must not disturb the node's position in the tree.
    expect(record?.sortOrder).toBe(sortBefore)
  })

  it('deletes a folder along with everything beneath it', () => {
    const a = createFolder(temp.db, null, 'a')
    const b = createFolder(temp.db, a, 'b')
    createHost(temp.db, hostInput({ parentId: b, label: 'deep' }))
    addHost(null, 'unrelated')

    deleteNode(temp.db, a)

    expect(layerNames(getConnectionTree(temp.db))).toEqual(['unrelated'])
    expect(listHosts(temp.db)).toHaveLength(1)
  })

  it('deletes a host on its own', () => {
    const folder = createFolder(temp.db, null, 'group')
    const host = createHost(temp.db, hostInput({ parentId: folder, label: 'gone' }))

    deleteNode(temp.db, host)

    const tree = getConnectionTree(temp.db)
    expect(tree).toHaveLength(1)
    if (tree[0].kind === 'folder') {
      expect(tree[0].children).toHaveLength(0)
    }
  })
})

/**
 * SQLite reports an UPDATE or DELETE that matched no rows as a successful
 * operation. Left unchecked, that turns every one of these into a silent
 * no-op — and the UI, which trusts the promise, reports success for a change
 * that never happened.
 */
describe('guards against missing rows', () => {
  const MISSING = 999_999

  it('renameFolder throws for an unknown id', () => {
    expect(() => renameFolder(temp.db, MISSING, 'x')).toThrow(/not found/)
  })

  it('moveNode throws for an unknown id', () => {
    expect(() => moveNode(temp.db, MISSING, null)).toThrow(/not found/)
  })

  it('deleteNode throws for an unknown id', () => {
    expect(() => deleteNode(temp.db, MISSING)).toThrow(/not found/)
  })

  it('updateHost throws for an unknown id', () => {
    expect(() => updateHost(temp.db, MISSING, hostInput())).toThrow(/not found/)
  })

  it('updateHost throws when handed a folder id', () => {
    // With one id space, a folder id is a syntactically valid node id — the
    // separate `hosts` table is what makes it fail rather than silently
    // editing nothing.
    const folder = createFolder(temp.db, null, 'not-a-host')
    expect(() => updateHost(temp.db, folder, hostInput())).toThrow(/not found/)
  })
})

describe('reading', () => {
  it('returns an empty tree for an empty inventory', () => {
    expect(getConnectionTree(temp.db)).toEqual([])
  })

  it('returns null for a folder id passed to getHost', () => {
    const folder = createFolder(temp.db, null, 'f')
    expect(getHost(temp.db, folder)).toBeNull()
  })

  it('lists every host with its parent', () => {
    const folder = createFolder(temp.db, null, 'group')
    createHost(temp.db, hostInput({ parentId: folder, label: 'nested' }))
    addHost(null, 'rooted')

    const hosts = listHosts(temp.db)
    expect(hosts).toHaveLength(2)
    expect(hosts.find((h) => h.label === 'nested')?.parentId).toBe(folder)
    expect(hosts.find((h) => h.label === 'rooted')?.parentId).toBeNull()
  })
})