import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { join } from 'node:path';
import { mkdtemp, mkdir, writeFile, rm } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import {
  assessSkillListingBudget,
  envFlag,
  isBundledSkillsDisabled,
  DESCRIPTION_CAP,
  AGGREGATE_BUDGET_TOKENS,
  CONTEXT_WINDOW_ANCHOR,
  LARGE_CONTEXT_WINDOW,
  LARGE_CONTEXT_BUDGET_TOKENS,
  withCommas,
  BUDGET_CALIBRATION_NOTE,
} from '../../scanners/lib/skill-listing-budget.mjs';

// This lib is the single source of truth for the skill-listing budget that both
// the SKL scanner (diagnoses overflow) and the GAP scanner (recommends the
// disableBundledSkills lever) consume. The constants and aggregate math here
// must match what SKL shipped in v5.2.0 — these tests pin that contract.

describe('skill-listing-budget — constants', () => {
  it('DESCRIPTION_CAP is the verified 1536-char listing cap (CC 2.1.105)', () => {
    assert.equal(DESCRIPTION_CAP, 1536);
  });

  it('AGGREGATE_BUDGET_TOKENS is 2% of the conservative 200k anchor', () => {
    assert.equal(CONTEXT_WINDOW_ANCHOR, 200_000);
    assert.equal(AGGREGATE_BUDGET_TOKENS, 4000);
  });

  it('LARGE_CONTEXT_BUDGET_TOKENS is 2% of the 1M window', () => {
    assert.equal(LARGE_CONTEXT_WINDOW, 1_000_000);
    assert.equal(LARGE_CONTEXT_BUDGET_TOKENS, 20000);
  });
});

describe('withCommas', () => {
  it('inserts thousands separators', () => {
    assert.equal(withCommas(1_000_000), '1,000,000');
    assert.equal(withCommas(4000), '4,000');
    assert.equal(withCommas(999), '999');
    assert.equal(withCommas(0), '0');
  });
});

describe('BUDGET_CALIBRATION_NOTE', () => {
  it('discloses the 1M-context scaling and flags this as an estimate, not telemetry', () => {
    assert.match(BUDGET_CALIBRATION_NOTE, /1,000,000/);
    assert.match(BUDGET_CALIBRATION_NOTE, /20,000/);
    assert.match(BUDGET_CALIBRATION_NOTE, /estimate/i);
  });
});

describe('assessSkillListingBudget — aggregate math', () => {
  it('sums each description length capped at the 1536 cap', () => {
    // 1000 + 1000 + min(5000,1536) = 3536
    const r = assessSkillListingBudget([1000, 1000, 5000]);
    assert.equal(r.aggregateChars, 3536);
  });

  it('scanned counts every entry, including empty descriptions', () => {
    const r = assessSkillListingBudget([0, 0, 100]);
    assert.equal(r.scanned, 3);
    assert.equal(r.aggregateChars, 100);
  });

  it('aggregateTokens mirrors estimateTokens markdown (ceil chars/4)', () => {
    const r = assessSkillListingBudget([16]); // 16 chars -> 4 tokens
    assert.equal(r.aggregateTokens, 4);
  });

  it('is NOT over budget exactly at the budget (16×1000 chars -> 4000 tok)', () => {
    const r = assessSkillListingBudget(Array(16).fill(1000));
    assert.equal(r.aggregateChars, 16000);
    assert.equal(r.aggregateTokens, 4000);
    assert.equal(r.overBudget, false);
    assert.equal(r.overBy, 0);
  });

  it('is over budget one skill past the budget (17×1000 chars -> 4250 tok)', () => {
    const r = assessSkillListingBudget(Array(17).fill(1000));
    assert.equal(r.aggregateTokens, 4250);
    assert.equal(r.overBudget, true);
    assert.equal(r.overBy, 250);
  });

  it('exposes budgetTokens and handles the empty case', () => {
    const r = assessSkillListingBudget([]);
    assert.equal(r.budgetTokens, AGGREGATE_BUDGET_TOKENS);
    assert.equal(r.scanned, 0);
    assert.equal(r.aggregateChars, 0);
    assert.equal(r.aggregateTokens, 0);
    assert.equal(r.overBudget, false);
    assert.equal(r.overBy, 0);
  });

  it('treats negative or non-finite lengths as zero contribution', () => {
    const r = assessSkillListingBudget([-5, NaN, 100]);
    assert.equal(r.aggregateChars, 100);
    assert.equal(r.scanned, 3);
  });
});

describe('envFlag', () => {
  it('treats 1/true/yes/on as set', () => {
    for (const v of ['1', 'true', 'TRUE', 'yes', 'on', ' 1 ']) {
      assert.equal(envFlag(v), true, `expected ${JSON.stringify(v)} → true`);
    }
  });

  it('treats null/empty/0/false/no/off as un-set', () => {
    for (const v of [undefined, null, '', '0', 'false', 'no', 'off', ' ']) {
      assert.equal(envFlag(v), false, `expected ${JSON.stringify(v)} → false`);
    }
  });
});

describe('isBundledSkillsDisabled — lever cascade', () => {
  async function withHome(fn) {
    const home = await mkdtemp(join(tmpdir(), 'config-audit-lever-home-'));
    const originalHome = process.env.HOME;
    const originalEnv = process.env.CLAUDE_CODE_DISABLE_BUNDLED_SKILLS;
    process.env.HOME = home;
    delete process.env.CLAUDE_CODE_DISABLE_BUNDLED_SKILLS;
    try {
      return await fn(home);
    } finally {
      process.env.HOME = originalHome;
      if (originalEnv === undefined) delete process.env.CLAUDE_CODE_DISABLE_BUNDLED_SKILLS;
      else process.env.CLAUDE_CODE_DISABLE_BUNDLED_SKILLS = originalEnv;
      await rm(home, { recursive: true, force: true });
    }
  }

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

  it('is false on a clean HOME with no env and no settings', async () => {
    await withHome(async () => {
      assert.equal(await isBundledSkillsDisabled(), false);
    });
  });

  it('is true when the env var is set', async () => {
    await withHome(async () => {
      process.env.CLAUDE_CODE_DISABLE_BUNDLED_SKILLS = '1';
      assert.equal(await isBundledSkillsDisabled(), true);
    });
  });

  it('is true when user ~/.claude/settings.json sets it (the location discovery misses)', async () => {
    await withHome(async (home) => {
      await writeSettings(join(home, '.claude'), { disableBundledSkills: true });
      assert.equal(await isBundledSkillsDisabled(), true);
    });
  });

  it('is true when project .claude/settings.json sets it', async () => {
    await withHome(async () => {
      const project = await mkdtemp(join(tmpdir(), 'config-audit-lever-proj-'));
      try {
        await writeSettings(join(project, '.claude'), { disableBundledSkills: true });
        assert.equal(await isBundledSkillsDisabled(project), true);
      } finally {
        await rm(project, { recursive: true, force: true });
      }
    });
  });

  it('is false when the setting is present but not strictly true', async () => {
    await withHome(async (home) => {
      await writeSettings(join(home, '.claude'), { disableBundledSkills: false });
      assert.equal(await isBundledSkillsDisabled(), false);
    });
  });
});