/** Raw Session journal transport and message-aligned pagination coverage. */

import { describe, expect, it, vi } from 'vitest'
import { Context } from '@deepseek-ai/cordis'
import AgentRegistry from '@deepseek-ai/dsh-agent'
import SessionStore from '@deepseek-ai/dsh-session'
import { decodeStorageRecord } from '@deepseek-ai/dsh-session/chunk-rows'
import { CallId, createMessage, createToolResultMessage, createUserMessage } from '@deepseek-ai/dsh-llm'
import type { Session, SessionEvent, SessionId } from '@deepseek-ai/dsh-session'
import { SessionHistoryController } from '@deepseek-ai/dsh-api-session-controller/src/history.ts'
import type {
  SessionFollowFrame,
  SessionPage,
  SessionWireEvent,
} from '@deepseek-ai/dsh-api-session-controller/types'
import { createSessionTestRemote, installSessionReadTestServices } from './test-remote.ts'

/** Append a production-shaped human prompt to the session surface. */
function appendUserText(session: Session, text: string): SessionEvent {
  return session.append('user/message', createUserMessage({
    content: [{ type: 'text', text }], source: { kind: 'user' },
  }), { surfaceOp: 'append' })
}

/** Append a production-shaped assistant message to the session surface. */
function appendAssistantText(session: Session, text: string, step: number): SessionEvent {
  return session.append('assistant/message', {
    turn: 1,
    step,
    message: createMessage({
      role: 'assistant',
      content: [{ type: 'text', text }],
      source: { kind: 'model', provider: 'p', model: 'm' },
    }),
  }, { surfaceOp: 'append' })
}

/**
 * Append a plugin-owned log-only event. The host proxy is projection-only, so it
 * declares no compaction vocabulary; the cast writes the real event shape without
 * depending on the owning package.
 */
function appendExtension(session: Session, type: string, data: unknown): SessionEvent {
  return (session.append as unknown as (type: string, data: unknown) => SessionEvent)(type, data)
}

async function harness(): Promise<{ ctx: Context }> {
  const ctx = new Context()
  await ctx.plugin(SessionStore)
  await ctx.plugin(AgentRegistry)
  installSessionReadTestServices(ctx)
  return { ctx }
}

/** Drain one Session follow until `count` event frames arrive. */
async function collect(
  iterable: AsyncIterable<SessionFollowFrame>,
  count: number,
  abort: AbortController,
): Promise<SessionFollowFrame[]> {
  const frames: SessionFollowFrame[] = []
  for await (const frame of iterable) {
    frames.push(frame)
    if (frames.filter(candidate => candidate.type === 'event').length >= count) abort.abort()
  }
  return frames
}

/** Open follow and wait until its cursor is fixed before appending fixtures. */
async function openFollow(
  history: SessionHistoryController,
  sessionId: SessionId,
  signal: AbortSignal,
): Promise<AsyncIterable<SessionFollowFrame>> {
  const iterator = history.follow({
    address: { kind: 'session', sessionId },
  }, signal)[Symbol.asyncIterator]()
  await expect(iterator.next()).resolves.toMatchObject({
    done: false,
    value: { type: 'snapshot' },
  })
  return { [Symbol.asyncIterator]: () => iterator }
}

/** Expand packed page records for assertions over the logical journal. */
function pageEvents(page: SessionPage): SessionWireEvent[] {
  return page.records.flatMap(record => 'event' in record
    ? [record.event]
    : decodeStorageRecord(record.chunks).map(event => event as unknown as SessionWireEvent))
}

describe('Session history raw journal', () => {
  it('follows raw tool events and preserves result metadata without a Tools service', async () => {
    const { ctx } = await harness()
    const session = ctx.sessions.create(undefined, { meta: { cwd: '/workspace' } })
    const history = new SessionHistoryController(ctx, (observation) => { observation[Symbol.dispose]() })
    const abort = new AbortController()
    const stream = await openFollow(history, session.id, abort.signal)
    const collected = collect(stream, 2, abort)
    const call = session.append('tool/call', {
      turn: 1, step: 1, callId: CallId('raw-call'), name: 'custom', arguments: '{malformed',
    })
    const result = session.append('tool/result', {
      turn: 1, step: 1,
      message: createToolResultMessage({
        callId: CallId('raw-call'),
        content: [{ type: 'text', text: 'raw output' }],
        isError: false,
      }),
      meta: { nested: { count: 2 }, paths: ['a.ts', 'b.ts'] },
    }, { surfaceOp: 'append' })

    const frames = await collected
    expect(frames).toEqual([
      { type: 'event', event: call },
      { type: 'event', event: result },
    ])
    expect((frames[1] as Extract<SessionFollowFrame, { type: 'event' }>).event.data)
      .toMatchObject({ meta: { nested: { count: 2 }, paths: ['a.ts', 'b.ts'] } })
  })

  it('follows live results without rescanning Session history', async () => {
    const { ctx } = await harness()
    const session = ctx.sessions.create(undefined, { meta: { cwd: '/workspace' } })
    const history = new SessionHistoryController(ctx, (observation) => { observation[Symbol.dispose]() })
    const abort = new AbortController()
    const stream = await openFollow(history, session.id, abort.signal)
    const iterator = stream[Symbol.asyncIterator]()

    session.append('tool/call', {
      turn: 1, step: 1, callId: CallId('live-fast'), name: 'term', arguments: '{"cmd":"pwd"}',
    })
    await expect(iterator.next()).resolves.toMatchObject({
      value: { type: 'event', event: { type: 'tool/call', data: { callId: 'live-fast' } } },
    })

    const events = vi.spyOn(session, 'events', 'get').mockImplementation(() => {
      throw new Error('live result rescanned Session history')
    })
    try {
      session.append('tool/result', {
        turn: 1, step: 1,
        message: createToolResultMessage({
          callId: CallId('live-fast'),
          content: [{ type: 'text', text: 'ok' }],
          isError: false,
        }),
      }, { surfaceOp: 'append' })
      await expect(iterator.next()).resolves.toMatchObject({
        value: { type: 'event', event: { type: 'tool/result', data: { message: { source: { callId: 'live-fast' } } } } },
      })
    } finally {
      events.mockRestore()
      abort.abort()
      await iterator.next()
      await ctx.fiber.dispose()
    }
  })

  it('serves raw call and result entries without parsing tool arguments', async () => {
    const { ctx } = await harness()
    const remote = createSessionTestRemote(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp' })
    const session = ctx.sessions.create(undefined, { meta: { cwd: '/workspace' } })
    const start = session.append('turn/start', { turn: 1 })
    const call = session.append('tool/call', {
      turn: 1, step: 1, callId: CallId('history-call'), name: 'custom', arguments: '{broken',
    })
    const result = session.append('tool/result', {
      turn: 1, step: 1,
      message: createToolResultMessage({
        callId: CallId('history-call'),
        content: [{ type: 'text', text: 'failed raw output' }],
        isError: true,
      }),
      meta: { persisted: true, count: 3 },
    }, { surfaceOp: 'append' })

    const response = await remote.page({
      address: { kind: 'session', sessionId: session.id },
      throughSeq: session.seq - 1,
    })
    expect(response.ok).toBe(true)
    if (!response.ok) throw new Error('unreachable')
    expect(response.value.records).toEqual([
      { event: start },
      { event: call },
      { event: result },
    ])
  })

  it('counts only append-origin messages toward maxMessages and keeps each compaction summary with its replacement', async () => {
    const { ctx } = await harness()
    const remote = createSessionTestRemote(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp' })
    const session = ctx.sessions.create(undefined, { meta: { cwd: '/workspace' } })
    session.append('turn/start', { turn: 1 })
    const first = appendUserText(session, 'first prompt')
    appendAssistantText(session, 'first reply', 1)
    const third = appendUserText(session, 'second prompt')
    appendAssistantText(session, 'second reply', 2)
    const shadowed = [...session.surface.nodes]
    // A compaction transaction: a log-only summary record immediately followed by the
    // replacement that shadows the range.
    const summary = appendExtension(session, 'compaction/summary', {
      summary: [{ type: 'text', text: 'summary' }],
      shadowedRange: { start: shadowed[0], end: shadowed.at(-1) },
      shadowedSeqs: shadowed,
      shadowedTokenCount: 0,
      provider: 'p',
      model: 'm',
    })
    session.append('user/message', createUserMessage({
      content: [{ type: 'text', text: '<context_checkpoint>summary</context_checkpoint>' }],
      source: { kind: 'plugin', plugin: 'compact' },
    }), {
      surfaceOp: { op: 'replace', start: shadowed[0] as number, end: shadowed.at(-1) as number },
      sourceEventSeqs: [...shadowed, summary.seq],
    })

    const response = await remote.page({
      address: { kind: 'session', sessionId: session.id },
      throughSeq: session.seq - 1,
      maxMessages: 2,
    })
    if (!response.ok) throw new Error('unreachable')
    const page = pageEvents(response.value)
    // Two append-origin messages fill the page even though a replacement copy of
    // the same event type sits in the window: the copy is model-only.
    const messages = page.filter(event => event.type === 'user/message' || event.type === 'assistant/message')
    expect(messages.map(event => event.seq)).toEqual([third.seq, third.seq + 1, third.seq + 3])
    expect(page.some(event => event.seq === first.seq)).toBe(false)
    expect(response.value.hasMore).toBe(true)
    // The range stays contiguous, so the checkpoint's summary record is readable on
    // the same page as the checkpoint itself.
    const summaryIndex = page.findIndex(event => event.seq === summary.seq)
    expect(summaryIndex).toBeGreaterThan(-1)
    expect(page[summaryIndex + 1]?.seq).toBe(summary.seq + 1)
    expect(page.map(event => event.seq)).toEqual(page.map((_event, index) => third.seq + index))
  })

  it('paginates a message with many provenance sources without variadic argument expansion', async () => {
    const { ctx } = await harness()
    const remote = createSessionTestRemote(ctx, { defaultModelSelection: () => ({ provider: 'p', model: 'm' }), cwd: '/tmp' })
    const session = ctx.sessions.create(undefined, { meta: { cwd: '/workspace' } })
    session.append('turn/start', { turn: 1 })
    const sources = Array.from({ length: 128 }, () => session.append('assistant/chunk', {
      turn: 1,
      step: 1,
      chunk: { type: 'text-delta', index: 0, text: 'x' },
    }).seq)
    const message = session.append('assistant/message', {
      turn: 1,
      step: 1,
      message: createMessage({
        role: 'assistant',
        content: [{ type: 'text', text: 'x'.repeat(sources.length) }],
        source: { kind: 'model', provider: 'p', model: 'm' },
      }),
    }, { surfaceOp: 'append', sourceEventSeqs: sources })

    const scalarMin = Math.min
    const min = vi.spyOn(Math, 'min').mockImplementation((...values) => {
      if (values.length > 2) throw new RangeError('variadic minimum rejected by regression harness')
      return scalarMin(...values)
    })
    try {
      const response = await remote.page({
        address: { kind: 'session', sessionId: session.id },
        throughSeq: message.seq,
        maxMessages: 1,
      })
      if (!response.ok) throw new Error('unreachable')
      expect(pageEvents(response.value).map(event => event.seq)).toEqual([...sources, message.seq])
      expect(response.value.records.filter(record => 'chunks' in record)).toHaveLength(1)
      expect(response.value.hasMore).toBe(true)
    } finally {
      min.mockRestore()
    }
  })

  it('follows a result after turn/end without reading the addressed Session log', async () => {
    const { ctx } = await harness()
    const session = ctx.sessions.create(undefined, { meta: { cwd: '/workspace' } })
    const history = new SessionHistoryController(ctx, (observation) => { observation[Symbol.dispose]() })
    const abort = new AbortController()
    const stream = await openFollow(history, session.id, abort.signal)
    const iterator = stream[Symbol.asyncIterator]()

    session.append('turn/start', { turn: 1 })
    await expect(iterator.next()).resolves.toMatchObject({ value: { event: { type: 'turn/start' } } })
    session.append('tool/call', { turn: 1, step: 1, callId: CallId('c-late'), name: 'term', arguments: '{"cmd":"tail"}' })
    await expect(iterator.next()).resolves.toMatchObject({ value: { event: { type: 'tool/call' } } })
    session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
    await expect(iterator.next()).resolves.toMatchObject({ value: { event: { type: 'turn/end' } } })
    const events = vi.spyOn(session, 'events', 'get').mockImplementation(() => {
      throw new Error('live result rescanned Session history')
    })
    try {
      const result = session.append('tool/result', {
        turn: 1, step: 1,
        message: createToolResultMessage({
          callId: CallId('c-late'),
          content: [{ type: 'text', text: 'ok' }],
          isError: false,
        }),
      }, { surfaceOp: 'append' })
      await expect(iterator.next()).resolves.toEqual({
        done: false,
        value: { type: 'event', event: result },
      })
    } finally {
      events.mockRestore()
      abort.abort()
      await iterator.next()
      await ctx.fiber.dispose()
    }
  })
})