import { describe, expect, it } from 'vitest';
import {
  applyAgentEditOperation,
  undoAgentEditOperation,
  redoAgentEditOperation,
  createAgentConfig,
  priorityForRole,
  teacherCount,
  type AgentRoster,
  type AgentRosterHistory,
} from '@/lib/edit/agent-ops';
import { AGENT_COLOR_PALETTE } from '@/lib/constants/agent-defaults';
import type { GeneratedAgentConfig } from '@/lib/types/stage';

const T = (id: string, role = 'teacher'): GeneratedAgentConfig => ({
  id,
  name: id,
  role,
  persona: '',
  avatar: '/avatars/teacher.png',
  color: '#000',
  priority: priorityForRole(role),
});

describe('priorityForRole', () => {
  it('maps roles', () => {
    expect(priorityForRole('teacher')).toBe(10);
    expect(priorityForRole('assistant')).toBe(7);
    expect(priorityForRole('student')).toBe(5);
  });
});

describe('createAgentConfig', () => {
  it('assigns derived defaults by index', () => {
    const a = createAgentConfig('student', 13, 'gen-x');
    expect(a.id).toBe('gen-x');
    expect(a.role).toBe('student');
    expect(a.priority).toBe(5);
    // 13 % 10 === 3 -> AGENT_DEFAULT_AVATARS[3] = '/avatars/thinker.png'
    expect(a.avatar).toBe('/avatars/thinker.png');
  });
});

describe('applyAgentEditOperation (roster)', () => {
  it('adds', () => {
    const r = applyAgentEditOperation([T('a')], { type: 'agent.add', agent: T('b', 'student') });
    expect(r.map((x) => x.id)).toEqual(['a', 'b']);
  });
  it('updates and recomputes priority on role change', () => {
    const r = applyAgentEditOperation([T('a'), T('b', 'student')], {
      type: 'agent.update',
      id: 'b',
      patch: { role: 'assistant', name: 'TA' },
    });
    const b = r.find((x) => x.id === 'b')!;
    expect(b.role).toBe('assistant');
    expect(b.priority).toBe(7);
    expect(b.name).toBe('TA');
  });
  it('reorders', () => {
    const r = applyAgentEditOperation([T('a'), T('b', 'student'), T('c', 'student')], {
      type: 'agent.reorder',
      id: 'c',
      index: 0,
    });
    expect(r.map((x) => x.id)).toEqual(['c', 'a', 'b']);
  });
  it('deletes', () => {
    const r = applyAgentEditOperation([T('a'), T('b', 'student')], {
      type: 'agent.delete',
      id: 'b',
    });
    expect(r.map((x) => x.id)).toEqual(['a']);
  });
  it('blocks deleting the last teacher', () => {
    expect(() =>
      applyAgentEditOperation([T('a'), T('b', 'student')], { type: 'agent.delete', id: 'a' }),
    ).toThrow('LAST_TEACHER');
  });
  it('blocks role-changing the last teacher away', () => {
    expect(() =>
      applyAgentEditOperation([T('a')], {
        type: 'agent.update',
        id: 'a',
        patch: { role: 'student' },
      }),
    ).toThrow('LAST_TEACHER');
  });
});

describe('history overload + undo/redo', () => {
  it('records past and undoes/redoes', () => {
    let h: AgentRosterHistory = { past: [], present: [T('a')], future: [] };
    h = applyAgentEditOperation(h, { type: 'agent.add', agent: T('b', 'student') });
    expect(h.present.map((x) => x.id)).toEqual(['a', 'b']);
    h = undoAgentEditOperation(h);
    expect(h.present.map((x) => x.id)).toEqual(['a']);
    h = redoAgentEditOperation(h);
    expect(h.present.map((x) => x.id)).toEqual(['a', 'b']);
  });

  it('two agent.update ops on same agent+field produce two separate undo steps', () => {
    let h: AgentRosterHistory = { past: [], present: [T('a')], future: [] };
    h = applyAgentEditOperation(h, {
      type: 'agent.update',
      id: 'a',
      patch: { name: 'First Edit' },
    });
    h = applyAgentEditOperation(h, {
      type: 'agent.update',
      id: 'a',
      patch: { name: 'Second Edit' },
    });
    expect(h.present[0].name).toBe('Second Edit');
    h = undoAgentEditOperation(h);
    expect(h.present[0].name).toBe('First Edit');
    h = undoAgentEditOperation(h);
    expect(h.present[0].name).toBe('a');
  });

  it('caps past history at 50 after 60 adds', () => {
    let h: AgentRosterHistory = { past: [], present: [T('seed')], future: [] };
    for (let i = 0; i < 60; i++) {
      h = applyAgentEditOperation(h, { type: 'agent.add', agent: T(`cap-${i}`, 'student') });
    }
    expect(h.past.length).toBe(50);
  });
});

describe('createAgentConfig', () => {
  it('assigns color from AGENT_COLOR_PALETTE by index', () => {
    // index 13: 13 % 12 === 1 → AGENT_COLOR_PALETTE[1]
    const a = createAgentConfig('student', 13, 'color-test');
    expect(a.color).toBe(AGENT_COLOR_PALETTE[13 % 12]);
  });
});

describe('teacherCount', () => {
  it('returns 0 for empty roster', () => {
    expect(teacherCount([])).toBe(0);
  });

  it('counts only teachers in a mixed roster', () => {
    const roster: AgentRoster = [T('t1', 'teacher'), T('t2', 'teacher'), T('s1', 'student')];
    expect(teacherCount(roster)).toBe(2);
  });
});