import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtemp, mkdir, writeFile, rm } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import { resolveActiveModel } from '../../scanners/lib/active-model.mjs';

// B8b — resolveActiveModel reads the configured model so `--context-window auto`
// can probe it. Source precedence mirrors Claude Code's own resolution: the shell
// ANTHROPIC_MODEL override wins, otherwise the settings cascade (local > project >
// user). Fully file/env-injectable so it is hermetic under the test HOME.

async function withTempHome(fn) {
  const home = await mkdtemp(join(tmpdir(), 'config-audit-model-home-'));
  try {
    return await fn(home);
  } finally {
    await rm(home, { recursive: true, force: true });
  }
}

async function withTempProject(fn) {
  const project = await mkdtemp(join(tmpdir(), 'config-audit-model-proj-'));
  try {
    return await fn(project);
  } finally {
    await rm(project, { recursive: true, force: true });
  }
}

async function writeSettings(dir, file, obj) {
  await mkdir(dir, { recursive: true });
  await writeFile(join(dir, file), JSON.stringify(obj));
}

describe('resolveActiveModel — env override (ANTHROPIC_MODEL)', () => {
  it('returns the shell ANTHROPIC_MODEL when set, ignoring settings', async () => {
    await withTempHome(async (home) => {
      await writeSettings(join(home, '.claude'), 'settings.json', { model: 'claude-sonnet-4-6' });
      const env = { HOME: home, ANTHROPIC_MODEL: 'claude-opus-4-8[1m]' };
      assert.equal(await resolveActiveModel(null, { env }), 'claude-opus-4-8[1m]');
    });
  });

  it('an empty ANTHROPIC_MODEL is treated as unset (falls through to the cascade)', async () => {
    await withTempHome(async (home) => {
      await writeSettings(join(home, '.claude'), 'settings.json', { model: 'claude-sonnet-4-6' });
      const env = { HOME: home, ANTHROPIC_MODEL: '   ' };
      assert.equal(await resolveActiveModel(null, { env }), 'claude-sonnet-4-6');
    });
  });
});

describe('resolveActiveModel — settings cascade (local > project > user)', () => {
  it('reads the model from user ~/.claude/settings.json', async () => {
    await withTempHome(async (home) => {
      await writeSettings(join(home, '.claude'), 'settings.json', { model: 'claude-opus-4-8' });
      assert.equal(await resolveActiveModel(null, { env: { HOME: home } }), 'claude-opus-4-8');
    });
  });

  it('project settings.json overrides user settings', async () => {
    await withTempHome(async (home) => {
      await writeSettings(join(home, '.claude'), 'settings.json', { model: 'claude-opus-4-8' });
      await withTempProject(async (project) => {
        await writeSettings(join(project, '.claude'), 'settings.json', { model: 'claude-sonnet-4-6' });
        assert.equal(await resolveActiveModel(project, { env: { HOME: home } }), 'claude-sonnet-4-6');
      });
    });
  });

  it('settings.local.json overrides project settings (local wins)', async () => {
    await withTempHome(async (home) => {
      await withTempProject(async (project) => {
        await writeSettings(join(project, '.claude'), 'settings.json', { model: 'claude-sonnet-4-6' });
        await writeSettings(join(project, '.claude'), 'settings.local.json', { model: 'claude-opus-4-8[1m]' });
        assert.equal(await resolveActiveModel(project, { env: { HOME: home } }), 'claude-opus-4-8[1m]');
      });
    });
  });
});

describe('resolveActiveModel — nothing configured', () => {
  it('returns null on a clean HOME with no model anywhere (honest advisory fallback)', async () => {
    await withTempHome(async (home) => {
      assert.equal(await resolveActiveModel(null, { env: { HOME: home } }), null);
    });
  });

  it('ignores a non-string model field', async () => {
    await withTempHome(async (home) => {
      await writeSettings(join(home, '.claude'), 'settings.json', { model: 123 });
      assert.equal(await resolveActiveModel(null, { env: { HOME: home } }), null);
    });
  });
});