/**
 * Tests for the browser half.
 *
 * There is no browser here, so the bundle is evaluated the way the real module
 * loader would — inside `window.__ModuleLoader__.load` — with a fake `require`
 * that supplies React and THROWS on anything else. That last part is the useful
 * one: it proves the bundle stays inside the platform's seed table, which is the
 * constraint a hand-written client half is most likely to break.
 *
 * The card is then rendered by calling the registered component and expanding
 * the elements it returns, and its handlers are driven directly. That is not a
 * substitute for looking at it in a browser, but it does check the wiring the
 * card cannot work without.
 */

import assert from 'node:assert/strict'
import { readFileSync } from 'node:fs'
import { test } from 'node:test'

const SOURCE = readFileSync(new URL('../client/client.js', import.meta.url), 'utf8')

/** Minimal React: enough for createElement plus the three hooks the card uses. */
function makeFakeReact() {
  const states = []
  let cursor = 0
  return {
    reset() {
      cursor = 0
    },
    api: {
      createElement: (type, props, ...children) => ({ type, props: props ?? {}, children }),
      useState(initial) {
        const index = cursor
        cursor += 1
        if (!(index in states)) states[index] = typeof initial === 'function' ? initial() : initial
        return [
          states[index],
          (next) => {
            states[index] = typeof next === 'function' ? next(states[index]) : next
          },
        ]
      },
      useEffect() {},
      useMemo(factory) {
        return factory()
      },
    },
  }
}

/** Evaluate the bundle against a fake loader and return its exports. */
function loadBundle() {
  let loaded
  const window = { __ModuleLoader__: { load: (spec) => { loaded = spec } } }
  new Function('window', SOURCE)(window)
  assert.ok(loaded !== undefined, 'the bundle must call window.__ModuleLoader__.load')
  const react = makeFakeReact()
  const exported = loaded.factory((name) => {
    if (name === 'react') return react.api
    throw new Error(`the client bundle required "${name}", which is not in the platform seed table`)
  })
  return { id: loaded.id, exported, react }
}

/**
 * Resolve function components by calling them, until a host element or null.
 *
 * This is the whole "renderer": the slot hands back an element whose type is the
 * card component, and function-typed children are expanded the same way.
 */
function expand(node, depth = 0) {
  if (depth > 50) throw new Error('the component tree did not settle')
  if (node === null || node === undefined) return null
  if (typeof node !== 'object') return node
  if (Array.isArray(node)) return node
  if (typeof node.type === 'function') return expand(node.type(node.props), depth + 1)
  return node
}

/** Depth-first walk over a rendered tree, expanding components as it goes. */
function findAll(node, predicate, out = []) {
  if (node === null || node === undefined) return out
  if (Array.isArray(node)) {
    for (const child of node) findAll(child, predicate, out)
    return out
  }
  if (typeof node !== 'object') return out
  if (typeof node.type === 'function') {
    findAll(expand(node), predicate, out)
    return out
  }
  if (predicate(node)) out.push(node)
  for (const child of node.children ?? []) findAll(child, predicate, out)
  return out
}

function textOf(node) {
  if (typeof node === 'string') return node
  if (node === null || node === undefined || typeof node !== 'object') return ''
  if (Array.isArray(node)) return node.map(textOf).join('')
  return (node.children ?? []).map(textOf).join('')
}

/** A SettingsScope stand-in recording the writes it was asked to make. */
function fakeScope(snapshot) {
  const calls = { set: [], unset: [] }
  return {
    calls,
    getSnapshot: () => snapshot,
    subscribe: () => () => {},
    set: async (field, value) => {
      calls.set.push([field, value])
    },
    unset: async (field) => {
      calls.unset.push(field)
    },
  }
}

const READY = {
  status: 'ready',
  value: { embeddingModel: '', embeddingDimensions: 0 },
  user: {},
  base: {},
  revision: 1,
  writable: true,
  mode: 'host',
}

/** Register the card the way the host would, and hand back its component. */
function registered() {
  const { id, exported, react } = loadBundle()
  let registration
  let render
  const ctx = {
    inject(deps, callback) {
      assert.deepEqual(deps, ['settingsScope'])
      callback({
        settingsScope: { bind: () => fakeScope(READY) },
        slots: {
          inject(_name, produce) {
            produce()
          },
          register(options, component) {
            registration = options
            render = component
          },
        },
      })
    },
  }
  exported.apply(ctx)
  const draw = (scope) => expand(render({ scope }))
  return { id, exported, react, registration, render, draw }
}

const inputFor = (tree, label) =>
  findAll(tree, (node) => node.type === 'input' && node.props['aria-label'] === label)[0]

const buttonStartingWith = (tree, prefix) =>
  findAll(tree, (node) => node.type === 'button' && textOf(node).startsWith(prefix))[0]

test('the bundle id matches the package name the loader is told about', () => {
  const { id } = loadBundle()
  assert.equal(id, 'dsh-slopo')
})

test('the client bundle requires nothing outside the platform seed table', () => {
  // loadBundle() throws on any specifier other than react.
  assert.doesNotThrow(() => loadBundle())
})

test('applying registers exactly one settings.plugin.item card, keyed on the namespace', () => {
  const { registration, exported } = registered()
  assert.equal(exported.name, 'dsh-slopo')
  assert.deepEqual(exported.inject, ['slots'])
  assert.equal(registration.name, 'settings.plugin.item')
  // The key must equal the Host namespace, or the tab never dispatches the card.
  assert.equal(registration.key, 'dsh-slopo')
})

test('the card renders a control for every setting the Host accepts', () => {
  const { draw } = registered()
  const tree = draw(fakeScope(READY))
  const labels = findAll(tree, (node) => node.type === 'label').map(textOf)
  for (const expected of [
    'Embedding model',
    'Embedding dimensions',
    'Embedding API base',
    'Embedding API key',
    'Extra embedding parameters',
    'slopo executable',
    'Source directory',
    'Exclude patterns',
    'State directory',
    'Ignore file',
    'Foreground timeout',
  ]) {
    assert.ok(
      labels.some((label) => label.includes(expected)),
      `no control labelled "${expected}"`,
    )
  }
})

test('the API key is rendered as a password field', () => {
  const { draw } = registered()
  const tree = draw(fakeScope(READY))
  assert.equal(inputFor(tree, 'Embedding API key').props.type, 'password')
})

test('the card renders nothing when the namespace is unavailable', () => {
  const { draw } = registered()
  assert.equal(draw(fakeScope({ ...READY, status: 'unavailable' })), null)
})

test('editing a field marks the card dirty and saving writes it through set()', async () => {
  const { draw, react } = registered()
  const scope = fakeScope(READY)

  inputFor(draw(scope), 'Embedding model').props.onChange({ target: { value: 'ollama/example:latest' } })

  // Re-render the way a state update would.
  react.reset()
  const tree = draw(scope)
  const save = buttonStartingWith(tree, 'Save')
  assert.equal(save.props.disabled, false, 'a changed field must enable Save')
  await save.props.onClick()

  assert.deepEqual(scope.calls.set, [['embeddingModel', 'ollama/example:latest']])
  assert.deepEqual(scope.calls.unset, [])
})

test('a whole number field is sent as a number, not the string the input holds', async () => {
  const { draw, react } = registered()
  const scope = fakeScope(READY)
  inputFor(draw(scope), 'Embedding dimensions').props.onChange({ target: { value: '768' } })
  react.reset()
  await buttonStartingWith(draw(scope), 'Save').props.onClick()
  assert.deepEqual(scope.calls.set, [['embeddingDimensions', 768]])
})

test('clearing a field is an unset, so it re-inherits rather than becoming empty', async () => {
  const { draw, react } = registered()
  const scope = fakeScope({ ...READY, value: { embeddingModel: 'ollama/old:latest', embeddingDimensions: 768 } })
  inputFor(draw(scope), 'Embedding model').props.onChange({ target: { value: '' } })
  react.reset()
  await buttonStartingWith(draw(scope), 'Save').props.onClick()
  assert.deepEqual(scope.calls.unset, ['embeddingModel'])
  assert.deepEqual(scope.calls.set, [], 'a cleared field must not be written as an empty string')
})

test('an exclude list round-trips through comma-separated text', async () => {
  const { draw, react } = registered()
  const scope = fakeScope({ ...READY, value: { embeddingModel: 'm', embeddingDimensions: 1 } })
  inputFor(draw(scope), 'Exclude patterns').props.onChange({ target: { value: '**/test/**, *.min.js' } })
  react.reset()
  await buttonStartingWith(draw(scope), 'Save').props.onClick()
  assert.deepEqual(scope.calls.set, [['sourceDirExclude', ['**/test/**', '*.min.js']]])
})

test('a boolean field writes a real boolean', async () => {
  const { draw, react } = registered()
  const scope = fakeScope(READY)
  const checkbox = findAll(
    draw(scope),
    (node) => node.type === 'input' && node.props['aria-label'] === 'Install slopo with uv when missing',
  )[0]
  checkbox.props.onChange({ target: { checked: true } })
  react.reset()
  await buttonStartingWith(draw(scope), 'Save').props.onClick()
  assert.deepEqual(scope.calls.set, [['autoInstall', true]])
})

test('an overridden field is marked, and Reset clears every override', async () => {
  const { draw } = registered()
  const scope = fakeScope({
    ...READY,
    value: { embeddingModel: 'ollama/x:latest', embeddingDimensions: 768 },
    user: { embeddingModel: 'ollama/x:latest', embeddingDimensions: 768 },
  })
  const tree = draw(scope)
  const labels = findAll(tree, (node) => node.type === 'label').map(textOf)
  assert.ok(labels.some((label) => label.includes('overridden')), 'a user-set field must be marked')

  const reset = buttonStartingWith(tree, 'Reset')
  assert.equal(reset.props.disabled, false)
  await reset.props.onClick()
  assert.deepEqual(scope.calls.unset.sort(), ['embeddingDimensions', 'embeddingModel'])
})

test('a read-only namespace disables every control', () => {
  const { draw } = registered()
  const tree = draw(fakeScope({ ...READY, writable: false, mode: 'memory' }))
  const inputs = findAll(tree, (node) => node.type === 'input')
  assert.ok(inputs.length > 0)
  for (const input of inputs) assert.equal(input.props.disabled, true)
})