/**
 * Tests for the sandbox-policy home: the deployment default (mode +
 * workspaceRoot) the service exposes, and the per-session `sandbox/mode`
 * override kit (fold + write path) both enforcing families read.
 */

import { mkdirSync, mkdtempSync, realpathSync, rmSync, symlinkSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join, resolve, sep } from 'node:path'
import { describe, expect, it } from 'vitest'
import { Context } from 'cordis'
import { Session, SessionId } from '@deepseek-ai/dsh-session'
import SandboxPolicyService, { SANDBOX_MODES, effectiveSandboxMode, setSandboxMode } from '@deepseek-ai/dsh-sandbox-policy'

async function mounted(config: { mode?: 'read-only' | 'workspace-write' | 'danger-full-access'; workspaceRoot?: string } = {}) {
  const ctx = new Context()
  await ctx.plugin(SandboxPolicyService, config)
  return ctx
}

function session(id: string, cwd?: string): Session {
  const sessionId = SessionId(id)
  return new Session(sessionId, undefined, {
    version: 0,
    id: sessionId,
    createdAt: 0,
    ...cwd === undefined ? {} : { cwd },
  })
}

describe('SandboxPolicyService', () => {
  it('defaults to read-only under the process cwd', async () => {
    const ctx = await mounted()
    expect(ctx.sandboxPolicy.defaultMode).toBe('read-only')
    expect(ctx.sandboxPolicy.workspaceRoot).toBe(resolve(process.cwd()))
  })

  it('carries a configured mode and resolves the workspace root absolute', async () => {
    const ctx = await mounted({ mode: 'workspace-write', workspaceRoot: '/ws/../ws/./sub' })
    expect(ctx.sandboxPolicy.defaultMode).toBe('workspace-write')
    expect(ctx.sandboxPolicy.workspaceRoot).toBe(resolve('/ws/../ws/./sub'))
  })

  it('resolves the deployment policy for an agentless call', async () => {
    const ctx = await mounted({ mode: 'workspace-write', workspaceRoot: '/fallback' })
    expect(ctx.sandboxPolicy.resolve()).toEqual({
      mode: 'workspace-write',
      workspaceRoot: resolve('/fallback'),
    })
  })

  it('resolves each session mode and cwd together without changing the fallback', async () => {
    const ctx = await mounted({ mode: 'workspace-write', workspaceRoot: '/fallback' })
    const first = session('sess-first', '/projects/first')
    const second = session('sess-second', '/projects/second')
    setSandboxMode(second, 'read-only')

    expect(ctx.sandboxPolicy.resolve({ session: first })).toEqual({
      mode: 'workspace-write',
      workspaceRoot: resolve('/projects/first'),
    })
    expect(ctx.sandboxPolicy.resolve({ session: second })).toEqual({
      mode: 'read-only',
      workspaceRoot: resolve('/projects/second'),
    })
    expect(ctx.sandboxPolicy.resolve()).toEqual({
      mode: 'workspace-write',
      workspaceRoot: resolve('/fallback'),
    })
  })

  it.skipIf(process.platform === 'win32')('resolves a symlink-sensitive session cwd with POSIX component semantics', async () => {
    const root = mkdtempSync(join(tmpdir(), 'dsh-policy-cwd-'))
    try {
      const lexical = join(root, 'lexical')
      const physical = join(root, 'physical')
      const child = join(physical, 'child')
      mkdirSync(lexical)
      mkdirSync(child, { recursive: true })
      const link = join(lexical, 'link')
      symlinkSync(child, link, 'dir')
      const cwd = `${link}${sep}..`
      const ctx = await mounted({ mode: 'workspace-write', workspaceRoot: '/fallback' })

      expect(ctx.sandboxPolicy.resolve({ session: session('sess-symlink-parent', cwd) })).toEqual({
        mode: 'workspace-write',
        workspaceRoot: realpathSync.native(physical),
      })
    } finally {
      rmSync(root, { recursive: true, force: true })
    }
  })

  it('lets an approved mode outrank the session mode while retaining its root', async () => {
    const ctx = await mounted({ workspaceRoot: '/fallback' })
    const active = session('sess-approved', '/projects/approved')
    setSandboxMode(active, 'read-only')
    expect(ctx.sandboxPolicy.resolve({ session: active, mode: 'danger-full-access' })).toEqual({
      mode: 'danger-full-access',
      workspaceRoot: resolve('/projects/approved'),
    })
  })

  it('uses the configured root when a session has no cwd', async () => {
    const ctx = await mounted({ workspaceRoot: '/fallback' })
    expect(ctx.sandboxPolicy.resolve({ session: session('sess-no-cwd') }).workspaceRoot).toBe(resolve('/fallback'))
  })

  it('rejects a mode outside the closed vocabulary at load', async () => {
    const ctx = new Context()
    // schemastery rejects the union violation when the plugin loads.
    await expect(ctx.plugin(SandboxPolicyService, { mode: 'yolo' as never })).rejects.toThrow()
  })

  it('unregisters cleanly from a child fiber (HMR safety)', async () => {
    const ctx = new Context()
    const fiber = await ctx.plugin(SandboxPolicyService, {})
    expect(ctx.sandboxPolicy).toBeDefined()
    await fiber.dispose()
    expect(ctx.get('sandboxPolicy')).toBeUndefined()
  })
})

describe('the sandbox/mode session kit', () => {
  it('SANDBOX_MODES lists every mode for advertisement and validation', () => {
    expect(SANDBOX_MODES).toEqual(['read-only', 'workspace-write', 'danger-full-access'])
  })

  it('effectiveSandboxMode folds to the last switch, or undefined without one', () => {
    const session = new Session(SessionId('sess-fold'))
    expect(effectiveSandboxMode(session.events)).toBeUndefined()
    setSandboxMode(session, 'workspace-write')
    setSandboxMode(session, 'read-only')
    expect(effectiveSandboxMode(session.events)).toBe('read-only')
  })

  it('setSandboxMode appends exactly one sandbox/mode event per switch', () => {
    const session = new Session(SessionId('sess-write'))
    setSandboxMode(session, 'danger-full-access')
    const modeEvents = session.events.filter(e => e.type === 'sandbox/mode')
    expect(modeEvents).toHaveLength(1)
    expect(modeEvents[0]?.data).toEqual({ mode: 'danger-full-access' })
  })
})

describe('delegation inheritance (overrideOf over the header baseline)', () => {
  /** A session whose header carries the delegation-inheritance baseline. */
  function inheritedSession(id: string, meta: { sandboxMode?: string; seedLength?: number } = {}): Session {
    const sessionId = SessionId(id)
    return new Session(sessionId, undefined, {
      version: 0,
      id: sessionId,
      createdAt: 0,
      ...meta.sandboxMode === undefined ? {} : { sandboxMode: meta.sandboxMode },
      ...meta.seedLength === undefined ? {} : { seedLength: meta.seedLength },
    })
  }

  it('overrideOf folds the session log and never falls back to the deployment default', async () => {
    const ctx = await mounted({ mode: 'workspace-write' })
    const parent = session('sess-inherit-parent')
    setSandboxMode(parent, 'workspace-write')
    setSandboxMode(parent, 'read-only')

    expect(ctx.sandboxPolicy.overrideOf(parent)).toBe('read-only')
    // undefined, NOT the deployment default — a child whose header froze the
    // default would stop following the LIVE default across resumes.
    expect(ctx.sandboxPolicy.overrideOf(session('sess-inherit-unswitched'))).toBeUndefined()
  })

  it('overrideOf reads the header baseline when the log has no own switch', async () => {
    const ctx = await mounted({ mode: 'workspace-write' })
    const child = inheritedSession('sess-inherit-baseline', { sandboxMode: 'read-only' })

    expect(ctx.sandboxPolicy.overrideOf(child)).toBe('read-only')
    // resolve() consumes the same chain, so enforcement sees the baseline.
    expect(ctx.sandboxPolicy.resolve({ session: child }).mode).toBe('read-only')
  })

  it('a seed-carried stale switch loses to the baseline; an OWN later switch wins over it', async () => {
    const ctx = await mounted({ mode: 'workspace-write' })
    // The fork seed carried the parent's OLD workspace-write switch (one
    // event, so seedLength 1); the delegation-time baseline is read-only.
    const child = inheritedSession('sess-inherit-slice', { sandboxMode: 'read-only', seedLength: 1 })
    setSandboxMode(child, 'workspace-write')
    expect(ctx.sandboxPolicy.overrideOf(child)).toBe('read-only')
    // A switch the child makes ITSELF (after the seed boundary) outranks it.
    setSandboxMode(child, 'danger-full-access')
    expect(ctx.sandboxPolicy.overrideOf(child)).toBe('danger-full-access')
  })

  it('rejects a header baseline outside the closed mode vocabulary (durable boundary)', async () => {
    const ctx = await mounted()
    const child = inheritedSession('sess-inherit-invalid', { sandboxMode: 'yolo' })

    expect(() => ctx.sandboxPolicy.overrideOf(child)).toThrow(/sandboxMode/)
  })
})