/**
 * @module tests/unit/plugin-version-coupling
 * @description Guards the brainy↔native-plugin version coupling (audit P0). A
 * mismatched or failed accelerator must FAIL LOUD, never silently fall back to
 * the default JS engine — that silent degrade was the #1 cross-repo drift
 * (e.g. an old @soulcraft/cor running invisibly against brainy 8.x). Covers:
 *   1. `pluginRangeSatisfies` (the dep-free semver-range matcher, incl. RC tags)
 *   2. `brainyRange` mismatch → init throws
 *   3. activate() throwing → init throws (no swallow)
 *   4. the legacy provider-key cliff ('hnsw' but not 'vector') → init throws
 *   5. an explicitly-listed plugin that can't load → init throws
 *   6. a graceful decline (activate()→false) → no throw, loud warn
 */
import { describe, it, expect } from 'vitest'
import { readFileSync } from 'node:fs'
import { fileURLToPath } from 'node:url'
import { dirname, join } from 'node:path'
import { Brainy } from '../../src/brainy.js'
import { getBrainyVersion } from '../../src/utils/version.js'
import { pluginRangeSatisfies, type BrainyPlugin, type BrainyPluginContext } from '../../src/plugin.js'

const PACKAGE_VERSION: string = JSON.parse(
  readFileSync(join(dirname(fileURLToPath(import.meta.url)), '../../package.json'), 'utf8')
).version

function memBrain(): Brainy {
  return new Brainy({ requireSubtype: false, storage: { type: 'memory' }, silent: true })
}

describe('pluginRangeSatisfies (dep-free range matcher)', () => {
  it('handles the comparator forms a brainyRange realistically uses', () => {
    expect(pluginRangeSatisfies('8.0.0', '>=8.0.0')).toBe(true)
    expect(pluginRangeSatisfies('7.31.2', '>=8.0.0')).toBe(false)
    expect(pluginRangeSatisfies('8.4.1', '>=8.0.0 <9.0.0')).toBe(true)
    expect(pluginRangeSatisfies('9.0.0', '>=8.0.0 <9.0.0')).toBe(false)
    expect(pluginRangeSatisfies('8.2.0', '^8.0.0')).toBe(true)
    expect(pluginRangeSatisfies('9.0.0', '^8.0.0')).toBe(false)
    expect(pluginRangeSatisfies('8.0.0', '=8.0.0')).toBe(true)
    expect(pluginRangeSatisfies('8.0.1', '=8.0.0')).toBe(false)
  })

  it('tolerates a prerelease tag on the running version (RC builds satisfy a stable floor)', () => {
    // The lockstep ships as 8.0.0-rc1 — it MUST satisfy cor's `>=8.0.0` range.
    expect(pluginRangeSatisfies('8.0.0-rc1', '>=8.0.0')).toBe(true)
    expect(pluginRangeSatisfies('8.0.0-rc1', '^8.0.0')).toBe(true)
    expect(pluginRangeSatisfies('8.0.0-rc1', '>=8.0.0 <9.0.0')).toBe(true)
  })

  it('fails OPEN on a malformed range (never blocks a valid brain on a bad declaration)', () => {
    expect(pluginRangeSatisfies('8.0.0', 'not-a-range')).toBe(true)
    expect(pluginRangeSatisfies('8.0.0', '')).toBe(true)
  })
})

describe('getBrainyVersion() — synchronously correct on first call', () => {
  it('returns the real package version, not a stale build-time default', () => {
    // Regression: the version was read async, so the FIRST (synchronous) call —
    // the one loadPlugins() makes to build context.version — returned a stale
    // default ('3.14.0'), which fails any realistic cor 3.x `>=8.0.0` range and
    // hard-rejects the matched native pairing on cold init. The sync read makes
    // the first call correct.
    const v = getBrainyVersion()
    expect(v).toBe(PACKAGE_VERSION)
    expect(v).not.toBe('3.14.0')
    expect(v).not.toBe('0.0.0') // the unknown-read sentinel must not surface in a real install
    expect(v.startsWith('8.')).toBe(true)
  })
})

/** A minimal fake plugin; `onActivate` lets a test register providers / throw. */
function fakePlugin(
  name: string,
  opts: { brainyRange?: string; onActivate?: (ctx: BrainyPluginContext) => boolean } = {}
): BrainyPlugin {
  return {
    name,
    brainyRange: opts.brainyRange,
    async activate(ctx) {
      return opts.onActivate ? opts.onActivate(ctx) : true
    }
  }
}

describe('version coupling at init() — no silent fallback', () => {
  it('throws when a plugin declares a brainyRange the running brainy is outside', async () => {
    const brain = memBrain()
    brain.use(fakePlugin('@fake/incompatible', { brainyRange: '>=999.0.0' }))
    await expect(brain.init()).rejects.toThrow(/supports brainy|version-matched/)
  })

  it('does NOT throw when the brainyRange is satisfied', async () => {
    const brain = memBrain()
    brain.use(fakePlugin('@fake/compatible', { brainyRange: '>=0.0.0' }))
    await expect(brain.init()).resolves.toBeUndefined()
    await brain.close()
  })

  it('does NOT throw for a realistic cor 3.x range (^8.0.0) on a COLD init', async () => {
    // The actual regression: loadPlugins() is the first init step and makes the
    // first getBrainyVersion() call, so a stale sync default would reject a
    // correctly-matched native provider declaring the real 8.x range. A fresh
    // brain registering a `^8.0.0` plugin must init cleanly.
    const brain = memBrain()
    brain.use(fakePlugin('@fake/cor-3x', { brainyRange: '^8.0.0' }))
    await expect(brain.init()).resolves.toBeUndefined()
    await brain.close()
  })

  it('throws (does not swallow) when activate() throws', async () => {
    const brain = memBrain()
    brain.use(fakePlugin('@fake/boom', { onActivate: () => { throw new Error('kaboom') } }))
    await expect(brain.init()).rejects.toThrow(/failed to activate|kaboom/)
  })

  it('throws on the legacy provider-key cliff (registers hnsw but not vector)', async () => {
    const brain = memBrain()
    brain.use(fakePlugin('@fake/old-cor', {
      onActivate: (ctx) => { ctx.registerProvider('hnsw', {}); return true }
    }))
    await expect(brain.init()).rejects.toThrow(/legacy vector provider|requires/)
  })

  it('a graceful decline (activate()→false) is non-fatal — init succeeds on the default engine', async () => {
    // Decline is a documented, non-fatal path (brainy logs a loud warning and
    // uses the default engine for that plugin's providers). The contract that
    // matters here: it does NOT abort init the way a hard failure does.
    const brain = memBrain()
    brain.use(fakePlugin('@fake/declines', { onActivate: () => false }))
    await expect(brain.init()).resolves.toBeUndefined()
    await brain.close()
  })

  it('throws when an explicitly-listed plugin package cannot be loaded', async () => {
    const brain = new Brainy({
      requireSubtype: false,
      storage: { type: 'memory' },
      silent: true,
      plugins: ['@soulcraft/this-package-does-not-exist-xyz']
    })
    await expect(brain.init()).rejects.toThrow(/could not be loaded|config\.plugins/)
  })
})
