import { describe, expect, it } from 'vitest';
import {
  getOrderedSessionParts,
  hydrateOpenCodeSession,
  reduceOpenCodeEvent,
} from '@/lib/opencode-session-state';

describe('OpenCode native session state', () => {
  it('hydrates native parts without dropping execution metadata', () => {
    const state = hydrateOpenCodeSession('ses_1', [{
      info: {
        id: 'msg_1',
        role: 'assistant',
        sessionID: 'ses_1',
        time: { created: 1_700_000_000_000 },
      },
      parts: [
        { id: 'text_1', type: 'text', text: 'Final answer' },
        { id: 'reason_1', type: 'reasoning', text: 'Checking the repository' },
        {
          id: 'tool_1',
          type: 'tool',
          tool: 'read',
          callID: 'call_1',
          state: {
            status: 'completed',
            input: { path: 'README.md' },
            output: 'ok',
            time: { start: 1_700_000_000_010, end: 1_700_000_000_110 },
          },
        },
        { id: 'step_1', type: 'step-finish', reason: 'stop', cost: 0.01 },
        { id: 'future_1', type: 'future-native-part', detail: 'preserve me' },
      ],
    }]);

    const parts = getOrderedSessionParts(state, 'msg_1');
    expect(parts.map((part) => part.type)).toEqual([
      'text',
      'reasoning',
      'tool',
      'step-finish',
      'unknown',
    ]);
    expect(parts[2]).toEqual(expect.objectContaining({
      tool: 'read',
      callID: 'call_1',
      state: expect.objectContaining({ status: 'completed' }),
    }));
    expect(parts.at(-1)).toEqual(expect.objectContaining({
      rawType: 'future-native-part',
      detail: expect.stringContaining('preserve me'),
    }));
  });

  it('applies full updates, deltas, and removals by stable part id', () => {
    const base = hydrateOpenCodeSession('ses_1', []);
    const updated = reduceOpenCodeEvent(base, {
      type: 'message.part.updated',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        part: { id: 'part_1', type: 'text', text: 'Hello' },
      },
    });
    const withDelta = reduceOpenCodeEvent(updated, {
      type: 'message.part.delta',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        partID: 'part_1',
        field: 'text',
        delta: ' world',
      },
    });
    const duplicateDelta = reduceOpenCodeEvent(withDelta, {
      type: 'message.part.delta',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        partID: 'part_1',
        field: 'text',
        delta: ' world',
      },
    });

    expect(getOrderedSessionParts(duplicateDelta, 'msg_1')[0]?.text).toBe('Hello world');

    const removed = reduceOpenCodeEvent(duplicateDelta, {
      type: 'message.part.removed',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        partID: 'part_1',
      },
    });
    expect(getOrderedSessionParts(removed, 'msg_1')).toEqual([]);
  });

  it('ignores events from another session and tracks native lifecycle status', () => {
    const state = hydrateOpenCodeSession('ses_1', []);
    const untouched = reduceOpenCodeEvent(state, {
      type: 'message.part.delta',
      payload: {
        sessionID: 'ses_2',
        messageID: 'msg_2',
        partID: 'part_2',
        delta: 'wrong session',
      },
    });
    expect(untouched).toBe(state);

    const busy = reduceOpenCodeEvent(state, {
      type: 'session.status',
      payload: { sessionID: 'ses_1', status: { type: 'retry' } },
    });
    expect(busy?.status).toBe('retry');

    const idle = reduceOpenCodeEvent(busy, {
      type: 'session.idle',
      payload: { sessionID: 'ses_1' },
    });
    expect(idle?.status).toBe('idle');
  });

  it('deduplicates replayed delta events by event identity without dropping equal real chunks', () => {
    let state = hydrateOpenCodeSession('ses_1', []);
    state = reduceOpenCodeEvent(state, {
      type: 'message.part.updated',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        part: { id: 'part_1', type: 'text', text: '' },
      },
    });
    state = reduceOpenCodeEvent(state, {
      type: 'message.part.delta',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        partID: 'part_1',
        delta: 'x',
        eventID: 'evt_1',
      },
    });
    state = reduceOpenCodeEvent(state, {
      type: 'session.status',
      payload: { sessionID: 'ses_1', status: { type: 'busy' } },
    });
    state = reduceOpenCodeEvent(state, {
      type: 'message.part.delta',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        partID: 'part_1',
        delta: 'x',
        eventID: 'evt_1',
      },
    });
    expect(getOrderedSessionParts(state, 'msg_1')[0]?.text).toBe('x');

    const secondRealChunk = reduceOpenCodeEvent(state, {
      type: 'message.part.delta',
      payload: {
        sessionID: 'ses_1',
        messageID: 'msg_1',
        partID: 'part_1',
        delta: 'x',
        eventID: 'evt_2',
      },
    });
    expect(getOrderedSessionParts(secondRealChunk, 'msg_1')[0]?.text).toBe('xx');
  });
});