import { mkdtempSync, writeFileSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import { Context } from '@deepseek-ai/cordis'
import AgentRegistry from '@deepseek-ai/dsh-agent'
import type { Agent } from '@deepseek-ai/dsh-agent'
import SessionStore, { SessionId } from '@deepseek-ai/dsh-session'
import type { SessionEvent, SessionHeader } from '@deepseek-ai/dsh-session'
import { TypertLookupFailure } from '@deepseek-ai/dsh-typert-protocol'
import TypertRegistry from '@deepseek-ai/dsh-typert-registry'
import { afterEach, describe, expect, it, vi } from 'vitest'
import {
  ApiSessionAgentController,
  ApiSessionCwdConflict,
  ApiSessionNotFound,
  ApiSessionSubagentOwnership,
  inspectApiSession,
} from '../src/agent.ts'

const roots: Context[] = []

afterEach(async () => {
  await Promise.all(roots.splice(0).map(ctx => ctx.fiber.dispose()))
})

async function harness(): Promise<{ ctx: Context; agents: ApiSessionAgentController }> {
  const ctx = new Context()
  roots.push(ctx)
  await ctx.plugin(TypertRegistry)
  await ctx.plugin(SessionStore)
  await ctx.plugin(AgentRegistry)
  ctx.provide('agentDefaultModel', {
    currentSelection: () => ({ provider: 'fixture', model: 'fixture-model' }),
    saveSelection: () => Promise.resolve(),
  } as never)
  return { ctx, agents: new ApiSessionAgentController(ctx) }
}

function header(id: string, cwd: string | null = '/workspace'): SessionHeader {
  return {
    version: 0,
    id: SessionId(id),
    createdAt: 1,
    ...(cwd === null ? {} : { cwd }),
  }
}

function agent(ctx: Context, meta: SessionHeader): Agent {
  const session = ctx.sessions.create(meta.id, { meta })
  return { id: meta.id, session, status: 'idle', ctx } as Agent
}

function unpublishedAgent(ctx: Context, meta: SessionHeader): Agent {
  return {
    id: meta.id,
    session: { id: meta.id, header: meta, events: [] },
    status: 'idle',
    ctx,
  } as unknown as Agent
}

describe('ApiSession identity failures', () => {
  it('describes cwd conflicts with and without a recorded cwd', () => {
    expect(new ApiSessionCwdConflict(SessionId('missing-cwd'), '/wanted', undefined).message)
      .toContain('records no cwd')
    expect(new ApiSessionCwdConflict(SessionId('wrong-cwd'), '/wanted', '/existing').message)
      .toContain('belongs to "/existing"')
  })

  it('rejects absent persistence, catalog misses, and cwd-less inspected artifacts', async () => {
    const ctx = new Context()
    roots.push(ctx)
    await expect(inspectApiSession(ctx, SessionId('missing')))
      .rejects.toThrow('session persistence is not configured')

    const inspect = vi.fn(() => Promise.resolve({ meta: header('missing'), events: [] as SessionEvent[] }))
    const disposeMissing = ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([]),
      inspect,
    } as never)
    await expect(inspectApiSession(ctx, SessionId('missing'))).rejects.toBeInstanceOf(ApiSessionNotFound)
    expect(inspect).not.toHaveBeenCalled()
    disposeMissing()

    const listed = header('cwd-less-catalog', null)
    const disposeListed = ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([listed]),
      inspect,
    } as never)
    await expect(inspectApiSession(ctx, listed.id)).rejects.toBeInstanceOf(ApiSessionNotFound)
    disposeListed()

    const catalog = header('cwd-less-inspect')
    const inspected = header('cwd-less-inspect', null)
    ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([catalog]),
      inspect: () => Promise.resolve({ meta: inspected, events: [] }),
    } as never)
    await expect(inspectApiSession(ctx, catalog.id)).rejects.toBeInstanceOf(ApiSessionNotFound)
  })
})

describe('ApiSession Agent lookup and recovery', () => {
  it('projects live Agent contexts and maps missing cold identities through Typert lookup failures', async () => {
    const { ctx } = await harness()
    const live = agent(ctx, header('live'))
    ctx.agents.register(live)
    ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([]),
      inspect: vi.fn(),
    } as never)
    const host = ctx.typert.contexts.getHost('agent')
    if (host === undefined) throw new Error('Agent Context resolver was not registered')

    await expect(host.resolve(live.id)).resolves.toBe(live.ctx)
    await expect(host.resolve(SessionId('missing'))).rejects.toBeInstanceOf(TypertLookupFailure)
  })

  it('returns raced ordinary Agents and ownership failures after resume throws', async () => {
    const ordinary = await harness()
    const ordinaryMeta = header('ordinary-race')
    ordinary.ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([ordinaryMeta]),
      inspect: () => Promise.resolve({ meta: ordinaryMeta, events: [] }),
    } as never)
    const winner = agent(ordinary.ctx, ordinaryMeta)
    vi.spyOn(ordinary.ctx.agents, 'resume').mockImplementation(async () => {
      ordinary.ctx.agents.register(winner)
      throw new Error('raced publication')
    })
    await expect(ordinary.agents.resolveAgent(ordinaryMeta.id)).resolves.toEqual({ agent: winner })

    const child = await harness()
    const childMeta = header('child-race')
    child.ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([childMeta]),
      inspect: () => Promise.resolve({ meta: childMeta, events: [] }),
    } as never)
    vi.spyOn(child.ctx.agents, 'resume').mockImplementation(async () => {
      child.ctx.sessions.create(childMeta.id, {
        meta: { ...childMeta, parentSession: SessionId('parent'), origin: 'subagent' },
      })
      throw new Error('raced child publication')
    })
    await expect(child.agents.resolveAgent(childMeta.id)).resolves.toMatchObject({
      error: { code: 'agent-busy' },
    })
  })

  it('reports not-found and ordinary resume failures without fabricating an Agent', async () => {
    const missing = await harness()
    missing.ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([]),
      inspect: vi.fn(),
    } as never)
    await expect(missing.agents.resolveAgent(SessionId('missing'))).resolves.toMatchObject({
      error: { code: 'session-not-found' },
    })

    const failed = await harness()
    const meta = header('failed')
    failed.ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([meta]),
      inspect: () => Promise.resolve({ meta, events: [] }),
    } as never)
    vi.spyOn(failed.ctx.agents, 'resume').mockRejectedValue(new Error('factory unavailable'))
    await expect(failed.agents.resolveAgent(meta.id)).resolves.toMatchObject({
      error: { code: 'internal', message: expect.stringContaining('factory unavailable') as string },
    })
  })
})

describe('ApiSession create or adoption', () => {
  it('shares one in-flight creation between concurrent callers', async () => {
    const { ctx, agents } = await harness()
    const cwd = mkdtempSync(join(tmpdir(), 'dsh-session-controller-concurrent-'))
    const meta = header('concurrent-create', cwd)
    const created = unpublishedAgent(ctx, meta)
    let release!: () => void
    const gate = new Promise<void>((resolve) => { release = resolve })
    const create = vi.spyOn(ctx.agents, 'create').mockImplementation(async () => {
      await gate
      return { agent: created, dispose: () => Promise.resolve() }
    })

    const first = agents.ensureSession(meta.id, cwd, false)
    const second = agents.ensureSession(meta.id, cwd, false)
    release()

    await expect(Promise.all([first, second])).resolves.toEqual([created, created])
    expect(create).toHaveBeenCalledOnce()
  })

  it('accepts a raced ordinary creation and rejects a raced attached child', async () => {
    const ordinary = await harness()
    const cwd = mkdtempSync(join(tmpdir(), 'dsh-session-controller-create-'))
    const ordinaryMeta = header('create-race', cwd)
    const winner = agent(ordinary.ctx, ordinaryMeta)
    vi.spyOn(ordinary.ctx.agents, 'create').mockImplementation(async () => {
      ordinary.ctx.agents.register(winner)
      throw new Error('raced creation')
    })
    await expect(ordinary.agents.ensureSession(ordinaryMeta.id, cwd, false))
      .resolves.toBe(winner)

    const child = await harness()
    const childCwd = mkdtempSync(join(tmpdir(), 'dsh-session-controller-child-'))
    const childId = SessionId('create-child-race')
    vi.spyOn(child.ctx.agents, 'create').mockImplementation(async () => {
      child.ctx.sessions.create(childId, {
        meta: { cwd: childCwd, parentSession: SessionId('parent'), origin: 'subagent' },
      })
      throw new Error('raced child creation')
    })
    await expect(child.agents.ensureSession(childId, childCwd, false))
      .rejects.toBeInstanceOf(ApiSessionSubagentOwnership)
  })

  it('validates ownership and cwd on the Agent returned by creation', async () => {
    const child = await harness()
    const childCwd = mkdtempSync(join(tmpdir(), 'dsh-session-controller-returned-child-'))
    const childMeta = {
      ...header('returned-child', childCwd),
      parentSession: SessionId('parent'),
      origin: 'subagent' as const,
    }
    const childAgent = unpublishedAgent(child.ctx, childMeta)
    vi.spyOn(child.ctx.agents, 'create').mockResolvedValue({
      agent: childAgent,
      dispose: () => Promise.resolve(),
    })
    await expect(child.agents.ensureSession(childMeta.id, childCwd, false))
      .rejects.toBeInstanceOf(ApiSessionSubagentOwnership)

    const wrong = await harness()
    const requestedCwd = mkdtempSync(join(tmpdir(), 'dsh-session-controller-wrong-cwd-'))
    const wrongAgent = unpublishedAgent(wrong.ctx, header('wrong-returned-cwd', '/other'))
    vi.spyOn(wrong.ctx.agents, 'create').mockResolvedValue({
      agent: wrongAgent,
      dispose: () => Promise.resolve(),
    })
    await expect(wrong.agents.ensureSession(wrongAgent.id, requestedCwd, false))
      .rejects.toBeInstanceOf(ApiSessionCwdConflict)
  })

  it('resumes a matching persisted identity and preserves its selected preset', async () => {
    const { ctx, agents } = await harness()
    const meta = { ...header('stored'), agentPreset: 'minimal' }
    const events = [{
      type: 'agent-preset/selected',
      seq: 0,
      time: 1,
      data: { agentPreset: 'minimal' },
    }] as SessionEvent[]
    ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([meta]),
      inspect: () => Promise.resolve({ meta, events }),
    } as never)
    ctx.provide('agentPresets', {
      resolve: (id?: string) => Promise.resolve({ id: id ?? 'minimal' }),
      mount: () => Promise.resolve(),
    } as never)
    const resumed = {
      id: meta.id,
      session: { id: meta.id, header: meta, events },
      status: 'idle',
      ctx,
    } as unknown as Agent
    const resume = vi.spyOn(ctx.agents, 'resume').mockResolvedValue({
      agent: resumed,
      dispose: () => Promise.resolve(),
    })

    await expect(agents.ensureSession(meta.id, '/workspace', true, 'minimal')).resolves.toBe(resumed)
    expect(resume).toHaveBeenCalledWith(expect.objectContaining({ resumeSessionId: meta.id }))
  })

  it('rejects an ownership race before resume and a persisted cwd conflict', async () => {
    const child = await harness()
    const childMeta = header('resume-child-race')
    child.ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([childMeta]),
      inspect: () => Promise.resolve({ meta: childMeta, events: [] }),
    } as never)
    child.ctx.provide('agentPresets', {
      resolve: () => {
        child.ctx.sessions.create(childMeta.id, {
          meta: { ...childMeta, parentSession: SessionId('parent'), origin: 'subagent' },
        })
        return Promise.resolve({ id: 'standard' })
      },
      mount: () => Promise.resolve(),
    } as never)
    await expect(child.agents.resolveAgent(childMeta.id)).resolves.toMatchObject({
      error: { code: 'agent-busy' },
    })

    const conflict = await harness()
    const stored = header('stored-cwd-conflict', '/stored')
    conflict.ctx.provide('sessionPersistence', {
      list: () => Promise.resolve([stored]),
      inspect: () => Promise.resolve({ meta: stored, events: [] }),
    } as never)
    await expect(conflict.agents.ensureSession(stored.id, '/requested', true))
      .rejects.toBeInstanceOf(ApiSessionCwdConflict)
  })

  it('surfaces directory creation failure and rejects setup without a scoped Agent', async () => {
    const { agents } = await harness()
    const parent = mkdtempSync(join(tmpdir(), 'dsh-session-controller-file-'))
    const file = join(parent, 'file')
    writeFileSync(file, 'not a directory')
    await expect(agents.ensureSession(SessionId('mkdir-failure'), join(file, 'child'), false))
      .rejects.toThrow('failed to ensure project directory')

    const composition = await agents.composeAgent(undefined)
    expect(() => composition.setup(new Context())).toThrow('Agent setup has no scoped Agent')
  })
})