import { describe, it, expect, beforeEach } from 'vitest';
import {
  computeLabelMutation,
  resolveLabelId,
  moveThreadToFolder,
  folderDisplayName,
  getManagedFolderKey,
  autoAdvanceFolder,
  MANAGED_USER_KEYS,
  __clearLabelCache
} from '../services/gmailLabels.js';

const FULL_IDS = {
  TRIAGE: 'L_TRIAGE',
  ESCALATED: 'L_ESC',
  RESOLVED: 'L_RES',
  FOR_JAKE: 'L_FJ',
  DASHBOARD_ERRORS: 'L_DE',
  PARTNERSHIP_OFFERS: 'L_PO',
  SPAM: 'SPAM'
};

const FULL_LABELS = [
  { name: 'Triage', id: 'L_TRIAGE' },
  { name: 'Awaiting Reply', id: 'L_AR' },
  { name: 'Needs Response', id: 'L_NR' },
  { name: 'Escalated', id: 'L_ESC' },
  { name: 'Resolved', id: 'L_RES' },
  { name: 'Complete', id: 'L_RES' },
  { name: 'For Jake', id: 'L_FJ' },
  { name: 'Dashboard Errors', id: 'L_DE' },
  { name: 'Partnership Offers', id: 'L_PO' }
];

describe('computeLabelMutation', () => {
  it('adds the target, removes every other managed label plus INBOX/UNREAD', () => {
    const { addLabelIds, removeLabelIds } = computeLabelMutation('FOR_JAKE', FULL_IDS);
    expect(addLabelIds).toEqual(['L_FJ']);
    expect(removeLabelIds).toContain('INBOX');
    expect(removeLabelIds).toContain('UNREAD');
    expect(removeLabelIds).toContain('SPAM');
    expect(removeLabelIds).toContain('L_TRIAGE');
    expect(removeLabelIds).not.toContain('L_FJ'); // target is never removed
  });

  it('moving to SPAM adds SPAM and removes all user labels but not SPAM itself', () => {
    const { addLabelIds, removeLabelIds } = computeLabelMutation('SPAM', FULL_IDS);
    expect(addLabelIds).toEqual(['SPAM']);
    expect(removeLabelIds).not.toContain('SPAM');
    expect(removeLabelIds).toContain('L_TRIAGE');
    expect(removeLabelIds).toContain('INBOX');
  });

  it('throws when the target id is missing', () => {
    expect(() => computeLabelMutation('FOR_JAKE', { TRIAGE: 'x' })).toThrow();
  });
});

describe('folderDisplayName', () => {
  it('returns null for the system SPAM folder', () => {
    expect(folderDisplayName('SPAM')).toBeNull();
  });
  it('returns the configured/default name for a user folder', () => {
    expect(folderDisplayName('FOR_JAKE')).toBe('For Jake');
  });
  it('throws on an unknown key', () => {
    expect(() => folderDisplayName('NOPE')).toThrow();
  });
});

describe('resolveLabelId', () => {
  beforeEach(() => __clearLabelCache());

  it('short-circuits SPAM to the system id without any API call', async () => {
    let called = false;
    const gmail = { users: { labels: { list: async () => { called = true; return { data: {} }; } } } };
    expect(await resolveLabelId(gmail, 'SPAM')).toBe('SPAM');
    expect(called).toBe(false);
  });

  it('returns an existing label id matched by name', async () => {
    const gmail = {
      users: { labels: {
        list: async () => ({ data: { labels: [{ name: 'For Jake', id: 'L_EXISTING' }] } }),
        create: async () => { throw new Error('should not create'); }
      } }
    };
    expect(await resolveLabelId(gmail, 'FOR_JAKE')).toBe('L_EXISTING');
  });

  it('creates a missing user label under its configured name and caches it', async () => {
    let createdName = null;
    const gmail = {
      users: { labels: {
        list: async () => ({ data: { labels: [] } }),
        create: async ({ requestBody }) => { createdName = requestBody.name; return { data: { id: 'L_NEW' } }; }
      } }
    };
    expect(await resolveLabelId(gmail, 'FOR_JAKE')).toBe('L_NEW');
    expect(createdName).toBe('For Jake');
  });
});

describe('moveThreadToFolder', () => {
  beforeEach(() => __clearLabelCache());

  it('resolves labels then issues one threads.modify with exclusive sets', async () => {
    let modifyArgs = null;
    const gmail = {
      users: {
        labels: {
          list: async () => ({ data: { labels: FULL_LABELS } }),
          create: async () => { throw new Error('no create expected'); }
        },
        threads: { modify: async (args) => { modifyArgs = args; return { data: {} }; } }
      }
    };
    await moveThreadToFolder('thread123', 'ESCALATED', gmail);
    expect(modifyArgs.id).toBe('thread123');
    expect(modifyArgs.requestBody.addLabelIds).toEqual(['L_ESC']);
    expect(modifyArgs.requestBody.removeLabelIds).toContain('L_TRIAGE');
    expect(modifyArgs.requestBody.removeLabelIds).toContain('INBOX');
    expect(modifyArgs.requestBody.removeLabelIds).not.toContain('L_ESC');
  });

  it('clears the cache and retries once on an invalid-label error', async () => {
    let modifyCalls = 0;
    let listCalls = 0;
    const gmail = {
      users: {
        labels: {
          list: async () => { listCalls++; return { data: { labels: FULL_LABELS } }; },
          create: async () => ({ data: { id: 'X' } })
        },
        threads: {
          modify: async () => {
            modifyCalls++;
            if (modifyCalls === 1) { const e = new Error('invalid label'); e.code = 400; throw e; }
            return { data: {} };
          }
        }
      }
    };
    await moveThreadToFolder('t1', 'TRIAGE', gmail);
    expect(modifyCalls).toBe(2);
    expect(listCalls).toBe(2); // cache was cleared and labels re-listed
  });

  it('rejects an unknown folder key before touching the API', async () => {
    const gmail = {
      users: {
        labels: { list: async () => ({ data: { labels: [] } }) },
        threads: { modify: async () => ({}) }
      }
    };
    await expect(moveThreadToFolder('t', 'BOGUS', gmail)).rejects.toThrow();
  });
});

// Derive label name↔id from the live config so these tests don't depend on the
// actual GMAIL_LABEL_* names in .env (e.g. RESOLVED may be customized to "Complete").
const idForKey = key => `LID_${key}`;
const CYCLE_LABELS = MANAGED_USER_KEYS.map(k => ({ name: folderDisplayName(k), id: idForKey(k) }));

// Mock Gmail whose thread carries the given label ids; records threads.modify.
function makeGmail({ threadLabelIds = [], onModify } = {}) {
  return {
    users: {
      labels: {
        list: async () => ({ data: { labels: CYCLE_LABELS } }),
        create: async () => { throw new Error('no create expected'); }
      },
      threads: {
        get: async () => ({ data: { messages: [{ labelIds: threadLabelIds }] } }),
        modify: async (args) => { if (onModify) onModify(args); return { data: {} }; }
      }
    }
  };
}

describe('getManagedFolderKey', () => {
  beforeEach(() => __clearLabelCache());

  it('maps a thread label id to its managed folder key', async () => {
    expect(await getManagedFolderKey('t', makeGmail({ threadLabelIds: [idForKey('FOR_JAKE'), 'INBOX'] }))).toBe('FOR_JAKE');
  });

  it('detects the system SPAM label', async () => {
    expect(await getManagedFolderKey('t', makeGmail({ threadLabelIds: ['SPAM'] }))).toBe('SPAM');
  });

  it('returns null when no managed label is present', async () => {
    expect(await getManagedFolderKey('t', makeGmail({ threadLabelIds: ['INBOX', 'UNREAD'] }))).toBeNull();
  });
});

describe('autoAdvanceFolder', () => {
  beforeEach(() => __clearLabelCache());

  it('advances an auto-cycle thread (Awaiting Reply → Needs Response)', async () => {
    let modifyArgs = null;
    const gmail = makeGmail({ threadLabelIds: [idForKey('AWAITING_REPLY')], onModify: a => { modifyArgs = a; } });
    expect(await autoAdvanceFolder('t', 'NEEDS_RESPONSE', gmail)).toBe(true);
    expect(modifyArgs.requestBody.addLabelIds).toEqual([idForKey('NEEDS_RESPONSE')]);
  });

  it('advances a thread with no managed label', async () => {
    let called = false;
    const gmail = makeGmail({ threadLabelIds: ['INBOX'], onModify: () => { called = true; } });
    expect(await autoAdvanceFolder('t', 'AWAITING_REPLY', gmail)).toBe(true);
    expect(called).toBe(true);
  });

  it('leaves a manually-filed thread (For Jake) untouched', async () => {
    let called = false;
    const gmail = makeGmail({ threadLabelIds: [idForKey('FOR_JAKE')], onModify: () => { called = true; } });
    expect(await autoAdvanceFolder('t', 'NEEDS_RESPONSE', gmail)).toBe(false);
    expect(called).toBe(false);
  });

  it('leaves a SPAM-filed thread untouched', async () => {
    let called = false;
    const gmail = makeGmail({ threadLabelIds: ['SPAM'], onModify: () => { called = true; } });
    expect(await autoAdvanceFolder('t', 'NEEDS_RESPONSE', gmail)).toBe(false);
    expect(called).toBe(false);
  });

  it('rejects an unknown target key before touching the API', async () => {
    await expect(autoAdvanceFolder('t', 'BOGUS', makeGmail())).rejects.toThrow();
  });
});