import { describe, expect, it } from 'vitest'
import { CallId } from '@deepseek-ai/dsh-llm'
import { interruptedTurnClosers } from '../src/index.ts'
import type { SessionEvent } from '../src/index.ts'

/**
 * Unit coverage for the crash-recovery closer synthesis. The persistence
 * contract exercises it end-to-end through both backends; these tests pin the
 * pure function's branches directly — especially the synthetic error
 * `tool/result` for a tool call the crash left unanswered (without it a
 * resumed session replays a dangling assistant tool-call and the provider
 * rejects the transcript).
 */

const userTurnStart = (turn: number, seq: number): SessionEvent =>
  ({ type: 'turn/start', seq, time: seq, data: { turn, trigger: { kind: 'message', source: { kind: 'user' } } } })

describe('interruptedTurnClosers', () => {
  it('returns nothing for a balanced log (ends on turn/end)', () => {
    const balanced: SessionEvent[] = [
      userTurnStart(1, 0),
      { type: 'turn/end', seq: 1, time: 1, data: { turn: 1, reason: { kind: 'completed' } } },
    ]
    expect(interruptedTurnClosers(balanced)).toEqual([])
  })

  it('returns nothing for an empty log', () => {
    expect(interruptedTurnClosers([])).toEqual([])
  })

  it('closes an open turn with no open step (turn/end {interrupted} only)', () => {
    const events: SessionEvent[] = [userTurnStart(1, 0)]
    const closers = interruptedTurnClosers(events)
    expect(closers.map(e => e.type)).toEqual(['turn/end'])
    const end = closers[0]!
    expect(end.seq).toBe(1)
    expect(end.type === 'turn/end' && end.data.reason).toEqual({ kind: 'interrupted' })
  })

  it('closes an open step before the turn (step/end then turn/end)', () => {
    const events: SessionEvent[] = [
      userTurnStart(1, 0),
      { type: 'step/start', seq: 1, time: 1, data: { turn: 1, step: 1 } },
    ]
    const closers = interruptedTurnClosers(events)
    expect(closers.map(e => e.type)).toEqual(['step/end', 'turn/end'])
    expect(closers.map(e => e.seq)).toEqual([2, 3])
  })

  it('synthesizes an error tool/result for a tool-call the crash left unanswered', () => {
    // A step issued one tool call (in the assistant message) but crashed before
    // the tool/result was logged — the classic mid-tool crash.
    const events: SessionEvent[] = [
      userTurnStart(2, 0),
      { type: 'step/start', seq: 1, time: 1, data: { turn: 2, step: 1 } },
      { type: 'assistant/message', seq: 2, time: 2, data: { turn: 2, step: 1, content: [
        { type: 'text', text: 'calling a tool' },
        { type: 'tool-call', id: CallId('call-1'), name: 'bash', arguments: '{}' },
      ] } },
    ]
    const closers = interruptedTurnClosers(events)
    // tool/result (for the orphaned call) → step/end → turn/end, contiguous seqs.
    expect(closers.map(e => e.type)).toEqual(['tool/result', 'step/end', 'turn/end'])
    expect(closers.map(e => e.seq)).toEqual([3, 4, 5])
    const result = closers[0]!
    expect(result.type === 'tool/result' && result.data).toMatchObject({
      turn: 2, step: 1, callId: CallId('call-1'), isError: true, error: { code: 'interrupted' },
    })
  })

  it('does NOT synthesize a result for a tool-call that already has one', () => {
    const events: SessionEvent[] = [
      userTurnStart(2, 0),
      { type: 'step/start', seq: 1, time: 1, data: { turn: 2, step: 1 } },
      { type: 'assistant/message', seq: 2, time: 2, data: { turn: 2, step: 1, content: [
        { type: 'tool-call', id: CallId('call-1'), name: 'bash', arguments: '{}' },
      ] } },
      { type: 'tool/result', seq: 3, time: 3, data: { turn: 2, step: 1, callId: CallId('call-1'), content: [{ type: 'text', text: 'ok' }], isError: false } },
    ]
    // The call is answered, so only the open step + turn need closing.
    const closers = interruptedTurnClosers(events)
    expect(closers.map(e => e.type)).toEqual(['step/end', 'turn/end'])
  })

  it('synthesizes results only for the still-open turn, not a committed earlier turn', () => {
    // Turn 1 completed with its own tool call+result (balanced). Turn 2 crashed
    // with an unanswered call. Only turn 2's call must get a synthetic result.
    const events: SessionEvent[] = [
      userTurnStart(1, 0),
      { type: 'step/start', seq: 1, time: 1, data: { turn: 1, step: 1 } },
      { type: 'assistant/message', seq: 2, time: 2, data: { turn: 1, step: 1, content: [
        { type: 'tool-call', id: CallId('old-call'), name: 'bash', arguments: '{}' },
      ] } },
      { type: 'tool/result', seq: 3, time: 3, data: { turn: 1, step: 1, callId: CallId('old-call'), content: [], isError: false } },
      { type: 'step/end', seq: 4, time: 4, data: { turn: 1, step: 1 } },
      { type: 'turn/end', seq: 5, time: 5, data: { turn: 1, reason: { kind: 'completed' } } },
      userTurnStart(2, 6),
      { type: 'step/start', seq: 7, time: 7, data: { turn: 2, step: 1 } },
      { type: 'assistant/message', seq: 8, time: 8, data: { turn: 2, step: 1, content: [
        { type: 'tool-call', id: CallId('new-call'), name: 'bash', arguments: '{}' },
      ] } },
    ]
    const closers = interruptedTurnClosers(events)
    expect(closers.map(e => e.type)).toEqual(['tool/result', 'step/end', 'turn/end'])
    const result = closers[0]!
    expect(result.type === 'tool/result' && result.data.callId).toBe('new-call')
  })

  it('synthesizes a result for each of multiple unanswered calls, in log order', () => {
    const events: SessionEvent[] = [
      userTurnStart(1, 0),
      { type: 'step/start', seq: 1, time: 1, data: { turn: 1, step: 1 } },
      { type: 'assistant/message', seq: 2, time: 2, data: { turn: 1, step: 1, content: [
        { type: 'tool-call', id: CallId('call-a'), name: 'bash', arguments: '{}' },
        { type: 'tool-call', id: CallId('call-b'), name: 'bash', arguments: '{}' },
      ] } },
      // call-a got answered before the crash; call-b did not.
      { type: 'tool/result', seq: 3, time: 3, data: { turn: 1, step: 1, callId: CallId('call-a'), content: [], isError: false } },
    ]
    const closers = interruptedTurnClosers(events)
    expect(closers.map(e => e.type)).toEqual(['tool/result', 'step/end', 'turn/end'])
    const result = closers[0]!
    expect(result.type === 'tool/result' && result.data.callId).toBe('call-b')
  })
})