import { describe, it, before, after, beforeEach, afterEach } from 'node:test';
import assert from 'node:assert/strict';
import { join, dirname, resolve } from 'node:path';
import { mkdir, writeFile, rm, readFile } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import {
  estimateTokens,
  detectGitRoot,
  walkClaudeMdCascade,
  readClaudeJsonProjectSlice,
  enumeratePlugins,
  enumerateSkills,
  readActiveHooks,
  readActiveMcpServers,
  readActiveConfig,
} from '../../scanners/lib/active-config-reader.mjs';

function uniqueDir(suffix) {
  return join(tmpdir(), `config-audit-acr-${suffix}-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`);
}

/**
 * Build a rich-repo fixture under `root`.
 * Layout mirrors feature plan §8 — git-repo, CLAUDE.md cascade, settings layers,
 * .mcp.json, fake-home with plugins + .claude.json.
 */
async function buildRichRepo(root) {
  const fakeHome = join(root, 'fake-home');
  // Repo marker
  await mkdir(join(root, '.git'), { recursive: true });
  await writeFile(join(root, '.git', 'HEAD'), 'ref: refs/heads/main\n');

  // Project CLAUDE.md with @import
  await mkdir(join(root, 'docs'), { recursive: true });
  await writeFile(
    join(root, 'CLAUDE.md'),
    '# Project Instructions\n\n@docs/conv.md\n\nBuild with care.\n',
  );
  await writeFile(join(root, 'docs', 'conv.md'), '# Conventions\n\nUse conventional commits.\n');

  // Settings cascade
  await mkdir(join(root, '.claude', 'rules'), { recursive: true });
  await writeFile(
    join(root, '.claude', 'settings.json'),
    JSON.stringify({
      permissions: { allow: ['Read', 'Write'] },
      hooks: {
        PreToolUse: [
          { matcher: 'Bash', hooks: [{ type: 'command', command: 'check.sh' }] },
        ],
      },
    }, null, 2),
  );
  await writeFile(
    join(root, '.claude', 'settings.local.json'),
    JSON.stringify({ env: { DEBUG: 'true' } }, null, 2),
  );
  await writeFile(join(root, '.claude', 'rules', 'team.md'), '# Team Rule\n');

  // Project .mcp.json
  await writeFile(
    join(root, '.mcp.json'),
    JSON.stringify({
      mcpServers: {
        alpha: { command: 'npx', args: ['alpha-server'] },
        beta: { command: 'npx', args: ['beta-server'] },
      },
    }, null, 2),
  );

  // Fake HOME — user CLAUDE.md, settings, plugins, .claude.json
  await mkdir(join(fakeHome, '.claude'), { recursive: true });
  await writeFile(
    join(fakeHome, '.claude', 'CLAUDE.md'),
    '# User Instructions\n\nBe terse.\n',
  );
  await writeFile(
    join(fakeHome, '.claude', 'settings.json'),
    JSON.stringify({
      hooks: {
        Stop: [{ hooks: [{ type: 'command', command: 'reminder.sh' }] }],
      },
    }, null, 2),
  );

  // Plugin: demo plugin with 1 command, 1 skill, 1 hook
  const pluginRoot = join(
    fakeHome, '.claude', 'plugins', 'marketplaces', 'mp', 'plugins', 'demo',
  );
  await mkdir(join(pluginRoot, '.claude-plugin'), { recursive: true });
  await writeFile(
    join(pluginRoot, '.claude-plugin', 'plugin.json'),
    JSON.stringify({ name: 'demo', description: 'test plugin', version: '0.1.0' }, null, 2),
  );
  await mkdir(join(pluginRoot, 'commands'), { recursive: true });
  await writeFile(
    join(pluginRoot, 'commands', 'foo.md'),
    '---\nname: demo:foo\ndescription: foo\nmodel: sonnet\n---\n\nFoo command.\n',
  );
  await mkdir(join(pluginRoot, 'skills', 'bar'), { recursive: true });
  await writeFile(
    join(pluginRoot, 'skills', 'bar', 'SKILL.md'),
    '---\nname: bar\ndescription: bar skill\n---\n\nBar skill body.\n',
  );
  await mkdir(join(pluginRoot, 'hooks'), { recursive: true });
  await writeFile(
    join(pluginRoot, 'hooks', 'hooks.json'),
    JSON.stringify({
      hooks: {
        PostToolUse: [{ hooks: [{ type: 'command', command: 'demo-hook.sh' }] }],
      },
    }, null, 2),
  );

  // ~/.claude.json with projects slice matching the repo root
  await writeFile(
    join(fakeHome, '.claude.json'),
    JSON.stringify({
      projects: {
        [root]: {
          mcpServers: {
            gamma: { command: 'gamma-server' },
          },
          disabledMcpjsonServers: ['beta'],
        },
      },
    }, null, 2),
  );

  return { root, fakeHome, pluginRoot };
}

// ─────────────────────────────────────────────────────────────────────────
// estimateTokens
// ─────────────────────────────────────────────────────────────────────────

describe('estimateTokens', () => {
  it('markdown: 4 chars per token, rounded up', () => {
    assert.equal(estimateTokens(400, 'markdown'), 100);
    assert.equal(estimateTokens(401, 'markdown'), 101);
    assert.equal(estimateTokens(0, 'markdown'), 0);
  });

  it('json: 3.5 chars per token, rounded up', () => {
    assert.equal(estimateTokens(350, 'json'), 100);
    assert.equal(estimateTokens(100, 'json'), 29);
  });

  it('frontmatter: caps at 600 bytes / 150 tokens', () => {
    assert.equal(estimateTokens(100, 'frontmatter'), 25);
    assert.equal(estimateTokens(600, 'frontmatter'), 150);
    assert.equal(estimateTokens(10_000, 'frontmatter'), 150);
  });

  it('item: flat 15 regardless of bytes', () => {
    assert.equal(estimateTokens(0, 'item'), 15);
    assert.equal(estimateTokens(9999, 'item'), 15);
  });

  it('defaults to markdown when kind omitted', () => {
    assert.equal(estimateTokens(400), 100);
  });

  it('handles invalid bytes gracefully', () => {
    assert.equal(estimateTokens(-1, 'markdown'), 0);
    assert.equal(estimateTokens(NaN, 'markdown'), 0);
  });

  // v5 F2: differentiated MCP estimate
  it('mcp: 0 bytes → at least 500 (base overhead floor)', () => {
    assert.ok(estimateTokens(0, 'mcp') >= 500,
      `expected >= 500, got ${estimateTokens(0, 'mcp')}`);
  });

  it('mcp: with toolCount: 10 → at least 2000', () => {
    assert.ok(estimateTokens(0, 'mcp', { toolCount: 10 }) >= 2000,
      `expected >= 2000, got ${estimateTokens(0, 'mcp', { toolCount: 10 })}`);
  });

  it('mcp: ratio mcp/item ≥ 30 for 10-tool server', () => {
    const mcp = estimateTokens(0, 'mcp', { toolCount: 10 });
    const item = estimateTokens(0, 'item');
    assert.ok(mcp / item >= 30,
      `expected ratio >= 30, got mcp=${mcp} item=${item} ratio=${mcp / item}`);
  });

  it('mcp: with bytes uses json-rate floor', () => {
    // 700 bytes JSON ≈ 200 tokens, but mcp keeps 500 floor
    assert.equal(estimateTokens(700, 'mcp'), 500);
    // 3500 bytes JSON = 1000 tokens, exceeds floor
    assert.equal(estimateTokens(3500, 'mcp'), 1000);
  });
});

// ─────────────────────────────────────────────────────────────────────────
// detectGitRoot
// ─────────────────────────────────────────────────────────────────────────

describe('detectGitRoot', () => {
  let root;
  before(async () => {
    root = uniqueDir('git');
    await mkdir(join(root, '.git'), { recursive: true });
    await mkdir(join(root, 'src', 'deep'), { recursive: true });
    await writeFile(join(root, '.git', 'HEAD'), '\n');
  });
  after(async () => { await rm(root, { recursive: true, force: true }); });

  it('finds .git in start dir', async () => {
    const result = await detectGitRoot(root);
    assert.equal(result, resolve(root));
  });

  it('walks up to find .git', async () => {
    const result = await detectGitRoot(join(root, 'src', 'deep'));
    assert.equal(result, resolve(root));
  });

  it('returns null when no .git in chain', async () => {
    const noGit = uniqueDir('nogit');
    await mkdir(noGit, { recursive: true });
    try {
      const result = await detectGitRoot(noGit);
      // Could resolve to outer repo (the plugin repo) if tmpdir happens to be nested.
      // Accept null OR a path that is NOT noGit itself.
      if (result !== null) {
        assert.notEqual(result, resolve(noGit));
      }
    } finally {
      await rm(noGit, { recursive: true, force: true });
    }
  });
});

// ─────────────────────────────────────────────────────────────────────────
// walkClaudeMdCascade
// ─────────────────────────────────────────────────────────────────────────

describe('walkClaudeMdCascade', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('cascade'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });

  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('returns files in load order (user first, then project, then imports)', async () => {
    const result = await walkClaudeMdCascade(fixture.root);
    const scopes = result.files.map(f => f.scope);
    assert.ok(scopes.includes('user'), 'expected user scope');
    assert.ok(scopes.includes('project'), 'expected project scope');
    assert.ok(scopes.includes('import'), 'expected import scope');

    // user CLAUDE.md should come before project CLAUDE.md
    const userIdx = result.files.findIndex(f => f.scope === 'user');
    const projIdx = result.files.findIndex(f => f.scope === 'project');
    assert.ok(userIdx < projIdx, 'user scope must come before project');
  });

  it('resolves @imports and marks them with parent', async () => {
    const result = await walkClaudeMdCascade(fixture.root);
    const imp = result.files.find(f => f.path.endsWith('docs/conv.md'));
    assert.ok(imp, 'import should be discovered');
    assert.equal(imp.scope, 'import');
    assert.ok(imp.parent && imp.parent.endsWith('CLAUDE.md'));
  });

  it('counts bytes and lines', async () => {
    const result = await walkClaudeMdCascade(fixture.root);
    assert.ok(result.totalBytes > 0);
    assert.ok(result.totalLines > 0);
    for (const f of result.files) {
      assert.ok(f.bytes > 0);
      assert.ok(f.lines > 0);
    }
  });

  it('computes estimatedTokens via markdown heuristic', async () => {
    const result = await walkClaudeMdCascade(fixture.root);
    assert.equal(result.estimatedTokens, Math.ceil(result.totalBytes / 4));
  });

  it('handles missing user CLAUDE.md gracefully', async () => {
    // Remove user CLAUDE.md
    await rm(join(fixture.fakeHome, '.claude', 'CLAUDE.md'));
    const result = await walkClaudeMdCascade(fixture.root);
    const userFiles = result.files.filter(f => f.scope === 'user');
    assert.equal(userFiles.length, 0);
  });
});

// ─────────────────────────────────────────────────────────────────────────
// readClaudeJsonProjectSlice
// ─────────────────────────────────────────────────────────────────────────

describe('readClaudeJsonProjectSlice', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('slice'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });
  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('finds exact-match project key', async () => {
    const slice = await readClaudeJsonProjectSlice(fixture.root);
    assert.equal(slice.projectKey, fixture.root);
    assert.deepEqual(slice.disabledMcpjsonServers, ['beta']);
    assert.ok('gamma' in slice.mcpServers);
  });

  it('returns empty slice when no .claude.json exists', async () => {
    await rm(join(fixture.fakeHome, '.claude.json'));
    const slice = await readClaudeJsonProjectSlice(fixture.root);
    assert.equal(slice.projectKey, null);
    assert.deepEqual(slice.mcpServers, {});
  });

  it('longest-prefix match: deeper key wins over shallower', async () => {
    // Rewrite .claude.json with two keys — ancestor and the repo
    const parent = dirname(fixture.root);
    const content = JSON.stringify({
      projects: {
        [parent]: { mcpServers: { shallow: { command: 'shallow' } } },
        [fixture.root]: { mcpServers: { deep: { command: 'deep' } } },
      },
    }, null, 2);
    await writeFile(join(fixture.fakeHome, '.claude.json'), content);

    const slice = await readClaudeJsonProjectSlice(fixture.root);
    assert.equal(slice.projectKey, fixture.root);
    assert.ok('deep' in slice.mcpServers);
    assert.ok(!('shallow' in slice.mcpServers));
  });

  it('ancestor prefix matches when target is a subdir of a key', async () => {
    const parent = dirname(fixture.root);
    await writeFile(
      join(fixture.fakeHome, '.claude.json'),
      JSON.stringify({ projects: { [parent]: { mcpServers: { anc: {} } } } }, null, 2),
    );
    const slice = await readClaudeJsonProjectSlice(fixture.root);
    assert.equal(slice.projectKey, parent);
  });

  it('returns null projectKey when no key matches', async () => {
    await writeFile(
      join(fixture.fakeHome, '.claude.json'),
      JSON.stringify({ projects: { '/some/other/path': {} } }, null, 2),
    );
    const slice = await readClaudeJsonProjectSlice(fixture.root);
    assert.equal(slice.projectKey, null);
  });
});

// ─────────────────────────────────────────────────────────────────────────
// enumeratePlugins
// ─────────────────────────────────────────────────────────────────────────

describe('enumeratePlugins', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('plugins'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });
  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('discovers plugin and reads plugin.json version', async () => {
    const plugins = await enumeratePlugins();
    assert.ok(plugins.length >= 1);
    const demo = plugins.find(p => p.name === 'demo');
    assert.ok(demo, 'demo plugin should be discovered');
    assert.equal(demo.version, '0.1.0');
  });

  it('counts commands, skills, hooks', async () => {
    const plugins = await enumeratePlugins();
    const demo = plugins.find(p => p.name === 'demo');
    assert.equal(demo.commands, 1);
    assert.equal(demo.skills, 1);
    assert.equal(demo.hooks, 1);
  });

  it('returns empty array when HOME has no plugins', async () => {
    process.env.HOME = uniqueDir('empty');
    await mkdir(process.env.HOME, { recursive: true });
    try {
      const plugins = await enumeratePlugins();
      assert.deepEqual(plugins, []);
    } finally {
      await rm(process.env.HOME, { recursive: true, force: true });
    }
  });
});

// ─────────────────────────────────────────────────────────────────────────
// enumerateSkills
// ─────────────────────────────────────────────────────────────────────────

describe('enumerateSkills', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('skills'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });
  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('finds plugin skills', async () => {
    const plugins = await enumeratePlugins();
    const skills = await enumerateSkills(plugins);
    const bar = skills.find(s => s.name === 'bar');
    assert.ok(bar, 'plugin skill should be discovered');
    assert.equal(bar.source, 'plugin');
    assert.equal(bar.pluginName, 'demo');
  });

  it('finds user skills', async () => {
    // Add a user skill
    await mkdir(join(fixture.fakeHome, '.claude', 'skills', 'userskill'), { recursive: true });
    await writeFile(
      join(fixture.fakeHome, '.claude', 'skills', 'userskill', 'SKILL.md'),
      '# user skill\n',
    );
    const skills = await enumerateSkills([]);
    const userSkill = skills.find(s => s.name === 'userskill');
    assert.ok(userSkill, 'user skill should be discovered');
    assert.equal(userSkill.source, 'user');
  });
});

// ─────────────────────────────────────────────────────────────────────────
// readActiveHooks
// ─────────────────────────────────────────────────────────────────────────

describe('readActiveHooks', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('hooks'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });
  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('merges hooks from user + project + plugin', async () => {
    const plugins = await enumeratePlugins();
    const hooks = await readActiveHooks(fixture.root, plugins);
    const sources = new Set(hooks.map(h => h.source));
    assert.ok(sources.has('user'), 'user hook present');
    assert.ok(sources.has('project'), 'project hook present');
    assert.ok([...sources].some(s => s.startsWith('plugin:')), 'plugin hook present');
  });

  it('does not dedupe across scopes', async () => {
    // Add duplicate hook in user and project settings
    const dupeHook = {
      hooks: { PreToolUse: [{ matcher: 'Bash', hooks: [{ type: 'command', command: 'same.sh' }] }] },
    };
    await writeFile(join(fixture.fakeHome, '.claude', 'settings.json'), JSON.stringify(dupeHook));
    await writeFile(join(fixture.root, '.claude', 'settings.json'), JSON.stringify(dupeHook));
    const hooks = await readActiveHooks(fixture.root, []);
    const sameCmd = hooks.filter(h => h.command === 'same.sh');
    assert.equal(sameCmd.length, 2, 'should report both occurrences');
  });
});

// ─────────────────────────────────────────────────────────────────────────
// readActiveMcpServers
// ─────────────────────────────────────────────────────────────────────────

describe('readActiveMcpServers', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('mcp'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });
  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('merges project .mcp.json + .claude.json slice', async () => {
    const servers = await readActiveMcpServers(fixture.root);
    const names = servers.map(s => s.name);
    assert.ok(names.includes('alpha'), 'alpha from project');
    assert.ok(names.includes('beta'), 'beta from project');
    assert.ok(names.includes('gamma'), 'gamma from .claude.json');
  });

  it('honors disabledMcpjsonServers', async () => {
    const servers = await readActiveMcpServers(fixture.root);
    const beta = servers.find(s => s.name === 'beta');
    assert.equal(beta.enabled, false);
    assert.equal(beta.disabledBy, 'disabledMcpjsonServers');

    const alpha = servers.find(s => s.name === 'alpha');
    assert.equal(alpha.enabled, true);
    assert.equal(alpha.disabledBy, null);
  });

  it('estimatedTokens >= 500 for every MCP server (v5 F2)', async () => {
    const servers = await readActiveMcpServers(fixture.root);
    assert.ok(servers.length > 0, 'fixture should produce MCP servers');
    for (const s of servers) {
      assert.ok(s.estimatedTokens >= 500,
        `${s.name} from ${s.source} has estimatedTokens=${s.estimatedTokens}, expected >= 500`);
    }
  });
});

// ─────────────────────────────────────────────────────────────────────────
// readActiveConfig (integration)
// ─────────────────────────────────────────────────────────────────────────

describe('readActiveConfig (integration)', () => {
  let fixture;
  let originalHome;

  beforeEach(async () => {
    fixture = await buildRichRepo(uniqueDir('full'));
    originalHome = process.env.HOME;
    process.env.HOME = fixture.fakeHome;
  });
  afterEach(async () => {
    process.env.HOME = originalHome;
    await rm(fixture.root, { recursive: true, force: true });
  });

  it('produces expected top-level shape', async () => {
    const result = await readActiveConfig(fixture.root);
    const keys = Object.keys(result).sort();
    assert.deepEqual(keys, [
      'claudeMd', 'hooks', 'mcpServers', 'meta', 'plugins',
      'settings', 'skills', 'suggestDisables', 'totals', 'warnings',
    ]);
  });

  it('meta contains required fields', async () => {
    const result = await readActiveConfig(fixture.root);
    assert.equal(result.meta.tool, 'config-audit:whats-active');
    assert.equal(result.meta.version, '1.0.0');
    assert.ok(typeof result.meta.generatedAt === 'string');
    assert.equal(result.meta.repoPath, resolve(fixture.root));
    assert.equal(result.meta.gitRoot, resolve(fixture.root));
    assert.equal(result.meta.projectKey, fixture.root);
    assert.ok(typeof result.meta.durationMs === 'number');
  });

  it('settings cascade reflects all three layers', async () => {
    const result = await readActiveConfig(fixture.root);
    const scopes = result.settings.cascade.map(c => c.scope);
    assert.deepEqual(scopes, ['user', 'project', 'local']);
    const user = result.settings.cascade.find(c => c.scope === 'user');
    const project = result.settings.cascade.find(c => c.scope === 'project');
    assert.equal(user.exists, true);
    assert.equal(project.exists, true);
  });

  it('totals.grandTotal equals sum of category subtotals', async () => {
    const result = await readActiveConfig(fixture.root);
    const t = result.totals.estimatedTokens;
    assert.equal(t.grandTotal, t.claudeMd + t.plugins + t.skills + t.mcpServers + t.hooks);
  });

  it('performance budget: durationMs < 2000', async () => {
    const result = await readActiveConfig(fixture.root);
    assert.ok(result.meta.durationMs < 2000,
      `expected < 2000ms, got ${result.meta.durationMs}ms`);
  });

  it('token estimate within ±20% of hand-computed value', async () => {
    const result = await readActiveConfig(fixture.root);
    const expectedClaudeMd = Math.ceil(result.claudeMd.totalBytes / 4);
    const low = Math.floor(expectedClaudeMd * 0.8);
    const high = Math.ceil(expectedClaudeMd * 1.2);
    assert.ok(
      result.totals.estimatedTokens.claudeMd >= low &&
      result.totals.estimatedTokens.claudeMd <= high,
      `claudeMd tokens ${result.totals.estimatedTokens.claudeMd} outside [${low}, ${high}]`,
    );
  });

  it('suggestDisables is null by default, object when flag set', async () => {
    const noFlag = await readActiveConfig(fixture.root);
    assert.equal(noFlag.suggestDisables, null);

    const withFlag = await readActiveConfig(fixture.root, { suggestDisables: true });
    assert.ok(withFlag.suggestDisables && Array.isArray(withFlag.suggestDisables.candidates));
  });

  it('suggestDisables flags disabled MCP servers', async () => {
    const result = await readActiveConfig(fixture.root, { suggestDisables: true });
    const betaCandidate = result.suggestDisables.candidates.find(
      c => c.kind === 'mcp' && c.name === 'beta',
    );
    assert.ok(betaCandidate, 'beta should be flagged as already disabled');
    assert.equal(betaCandidate.confidence, 'high');
  });
});