'use strict';

// Phase 1 tests for the STATE.md Transition Module (ADR-1769).
// These are characterization tests: they pin the behavior the new
// `transitionCore` / `beginPhase` API must preserve as the old
// `cmdStateBeginPhase` callback in state.cts is migrated onto it.
//
// Discipline: TDD vertical slices. One behavior → one test → minimal code → repeat.

const { describe, test } = require('node:test');
const assert = require('node:assert/strict');
const fc = require('fast-check');

const {
  transitionCore,
  FIELD_CLASSIFICATION,
  getFieldClassification,
  STATE_MD_SECTIONS,
} = require('../gsd-core/bin/lib/state-transition.cjs');
const { stateExtractField } = require('../gsd-core/bin/lib/state-document.cjs');

const fixedClock = Object.freeze({
  today: () => '2026-06-27',
  nowIso: () => '2026-06-27T12:00:00.000Z',
});

const noProgress = () => null;

describe('ADR-1769 substrate: field-classification table', () => {
  const allowedSources = new Set(['body', 'disk', 'external', 'curated', 'free']);
  const allowedPreservation = new Set([
    'derive',
    'preserve-when-unchanged',
    'preserve-always',
    'preserve-if-placeholder',
    'clear',
  ]);

  test('every classified field has a { source, preservation } row with known enum values', () => {
    for (const [field, cls] of Object.entries(FIELD_CLASSIFICATION)) {
      assert.ok(
        allowedSources.has(cls.source),
        `field ${JSON.stringify(field)} has unknown source ${JSON.stringify(cls.source)}`,
      );
      assert.ok(
        allowedPreservation.has(cls.preservation),
        `field ${JSON.stringify(field)} has unknown preservation ${JSON.stringify(cls.preservation)}`,
      );
    }
  });

  test('current_phase_name is curated / preserve-always (ADR-1769 §4 — kills #1743/#1695 by construction)', () => {
    const cls = getFieldClassification('current_phase_name');
    assert.strictEqual(cls && cls.source, 'curated');
    assert.strictEqual(cls && cls.preservation, 'preserve-always');
  });

  test('progress is curated / preserve-always (ADR-1769 §4 — curated-progress ratchet)', () => {
    const cls = getFieldClassification('progress');
    assert.strictEqual(cls && cls.source, 'curated');
    assert.strictEqual(cls && cls.preservation, 'preserve-always');
  });

  test('table covers every frontmatter key emitted by buildStateFrontmatter (codex Phase 1 review)', () => {
    // Verified against src/state.cts:1633-1653 (buildStateFrontmatter emit block).
    const requiredFields = [
      'gsd_state_version',
      'milestone',
      'milestone_name',
      'current_phase',
      'current_phase_name',
      'current_plan',
      'status',
      'stopped_at',
      'paused_at',
      'last_updated',
      'last_activity',
      'last_activity_desc',
      'progress',
      'progress.total_phases',
      'progress.completed_phases',
      'progress.total_plans',
      'progress.completed_plans',
      'progress.percent',
    ];
    for (const f of requiredFields) {
      assert.ok(getFieldClassification(f) !== null,
        `frontmatter key ${JSON.stringify(f)} must have a classification row`);
    }
  });

  test('getFieldClassification returns null for unknown fields AND inherited prototype methods', () => {
    // Classic prototype-pollution guard: queries for 'toString' / 'valueOf' / '__proto__'
    // must return null, not inherited Object.prototype functions.
    assert.strictEqual(getFieldClassification('toString'), null);
    assert.strictEqual(getFieldClassification('valueOf'), null);
    assert.strictEqual(getFieldClassification('hasOwnProperty'), null);
    assert.strictEqual(getFieldClassification('__proto__'), null);
    assert.strictEqual(getFieldClassification('not-a-real-field'), null);
  });
});

describe('ADR-1769 substrate: STATE_MD_SECTIONS constants (aligned to gsd-core/templates/state.md)', () => {
  test('every section heading starts with "## "', () => {
    for (const [name, heading] of Object.entries(STATE_MD_SECTIONS)) {
      assert.ok(
        heading.startsWith('## '),
        `section ${name} heading ${JSON.stringify(heading)} must start with "## "`,
      );
    }
  });

  test('matches the six canonical top-level sections of the STATE.md template', () => {
    assert.strictEqual(STATE_MD_SECTIONS.projectReference, '## Project Reference');
    assert.strictEqual(STATE_MD_SECTIONS.currentPosition, '## Current Position');
    assert.strictEqual(STATE_MD_SECTIONS.performanceMetrics, '## Performance Metrics');
    assert.strictEqual(STATE_MD_SECTIONS.accumulatedContext, '## Accumulated Context');
    assert.strictEqual(STATE_MD_SECTIONS.deferredItems, '## Deferred Items');
    assert.strictEqual(STATE_MD_SECTIONS.sessionContinuity, '## Session Continuity');
  });
});

describe('ADR-1769 Phase 1: beginPhase transition — tracer bullet', () => {
  test('updates body Status field to "Executing Phase N" on first-time begin', () => {
    const input = [
      '# Project State',
      '',
      '**Status:** Planning',
      '',
      '## Current Position',
      '',
      'Phase: 2 — DONE',
      'Plan: —',
      'Status: Planning',
      '',
    ].join('\n');

    const result = transitionCore(
      input,
      { kind: 'beginPhase', phaseNumber: 3, phaseName: 'Test Phase', planCount: 5 },
      { clock: fixedClock, progressProvider: noProgress },
    );

    assert.ok(result.updated.includes('Status'), `updated should include Status; got ${JSON.stringify(result.updated)}`);
    // The transition must produce a body Status field carrying "Executing Phase 3".
    // Use the same primitive the production code uses, not a source-grep.
    const bodyStatus = stateExtractField(result.content, 'Status');
    assert.ok(
      /Executing Phase\s+3\b/.test(bodyStatus || ''),
      `body Status should match /Executing Phase 3/; got ${JSON.stringify(bodyStatus)}`,
    );
  });
});

// Shared fixture for first-time begin: a clean STATE.md body where no
// "Executing Phase N" status is present yet.
function firstTimeBody() {
  return [
    '# Project State',
    '',
    '**Status:** Planning',
    '**Current Phase:** 02',
    '**Current Phase Name:** Previous Phase',
    '**Current Plan:** 02',
    '**Total Plans in Phase:** 3',
    '**Last Activity:** 2026-06-20',
    '**Last Activity Description:** previous work',
    '**Current focus:** Phase 2 — Previous Phase',
    '',
    '## Current Position',
    '',
    'Phase: 2 (Previous Phase)',
    'Plan: 2 of 3',
    'Status: Planning',
    'Last activity: 2026-06-20 — context gathered',
    '',
  ].join('\n');
}

describe('ADR-1769 Phase 1: beginPhase first-time body field updates', () => {
  const intent = { kind: 'beginPhase', phaseNumber: 3, phaseName: 'Test Phase', planCount: 5 };
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('updates Current Phase to N', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Phase'), '3');
    assert.ok(result.updated.includes('Current Phase'));
  });

  test('updates Current Phase Name when phaseName is provided', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Phase Name'), 'Test Phase');
    assert.ok(result.updated.includes('Current Phase Name'));
  });

  test('sets Current Plan to 1 on first-time begin', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Plan'), '1');
    assert.ok(result.updated.includes('Current Plan'));
  });

  test('updates Total Plans in Phase to planCount when provided', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Total Plans in Phase'), '5');
    assert.ok(result.updated.includes('Total Plans in Phase'));
  });

  test('updates Last Activity to clock.today()', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Last Activity'), '2026-06-27');
    assert.ok(result.updated.includes('Last Activity'));
  });

  test('updates Last Activity Description to "Phase N execution started"', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.strictEqual(
      stateExtractField(result.content, 'Last Activity Description'),
      'Phase 3 execution started',
    );
    assert.ok(result.updated.includes('Last Activity Description'));
  });

  test('updates **Current focus:** body text line (#1104)', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    // The **Current focus:** line should now carry the new phase label.
    const focusMatch = result.content.match(/\*\*Current focus:\*\*\s*(.*)/i);
    assert.ok(focusMatch, '**Current focus:** line must still be present');
    assert.strictEqual(focusMatch[1].trim(), 'Phase 3 — Test Phase');
    assert.ok(result.updated.includes('Current focus'),
      `updated should include 'Current focus'; got ${JSON.stringify(result.updated)}`);
  });
});

// Fixture for resume: a STATE.md body where Status already contains
// "Executing Phase 3" — the #3127 idempotency guard must detect this and
// skip the first-time-only field writes.
function resumeBody() {
  return [
    '# Project State',
    '',
    '**Status:** Executing Phase 3',
    '**Current Phase:** 03',
    '**Current Phase Name:** Test Phase',
    '**Current Plan:** 02',
    '**Total Plans in Phase:** 5',
    '**Last Activity:** 2026-06-26',
    '**Last Activity Description:** mid-flight context from plan 3-02',
    '',
    '## Current Position',
    '',
    'Phase: 3 (Test Phase) — EXECUTING',
    'Plan: 2 of 5',
    'Status: Executing Phase 3',
    'Last activity: 2026-06-26 — mid-flight context',
    '',
  ].join('\n');
}

describe('ADR-1769 Phase 1: #3127 idempotency guard — resume path', () => {
  const intent = { kind: 'beginPhase', phaseNumber: 3, phaseName: 'Test Phase', planCount: 5 };
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('Status is still refreshed on resume (Last Activity Date tracks execute-phase runs)', () => {
    const result = transitionCore(resumeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Last Activity'), '2026-06-27');
    assert.ok(result.updated.includes('Last Activity'));
  });

  test('Current Plan is NOT overwritten on resume (#3127 — preserves mid-flight plan number)', () => {
    const result = transitionCore(resumeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Plan'), '02');
    assert.ok(!result.updated.includes('Current Plan'),
      `Current Plan must not be in updated on resume; got ${JSON.stringify(result.updated)}`);
  });

  test('Total Plans in Phase is NOT overwritten on resume', () => {
    const result = transitionCore(resumeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Total Plans in Phase'), '5');
    assert.ok(!result.updated.includes('Total Plans in Phase'));
  });

  test('Last Activity Description is NOT overwritten on resume (#3127 — preserves mid-flight context)', () => {
    const result = transitionCore(resumeBody(), intent, deps);
    assert.strictEqual(
      stateExtractField(result.content, 'Last Activity Description'),
      'mid-flight context from plan 3-02',
    );
    assert.ok(!result.updated.includes('Last Activity Description'));
  });

  test('Current Phase Name is NOT overwritten on resume', () => {
    const result = transitionCore(resumeBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Phase Name'), 'Test Phase');
    assert.ok(!result.updated.includes('Current Phase Name'));
  });
});

describe('ADR-1769 Phase 1: Current Position section mutation (first-time begin)', () => {
  const intent = { kind: 'beginPhase', phaseNumber: 3, phaseName: 'Test Phase', planCount: 5 };
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('Current Position Phase line reflects the new phase (EXECUTING)', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    assert.ok(result.updated.includes('Current Position'),
      `updated should include Current Position; got ${JSON.stringify(result.updated)}`);
    // Verify by extracting Phase from the result content (covers both inline and pipe-table).
    // The transition writes "Phase: 3 (Test Phase) — EXECUTING" into ## Current Position.
    // stateExtractField returns the first match across the whole content, but the
    // **Current Phase:** frontmatter-style line is a different field, so 'Phase'
    // extraction finds the Current Position line.
    const posPhase = stateExtractField(result.content, 'Phase');
    assert.ok(
      /3.*Test Phase.*EXECUTING/.test(posPhase || ''),
      `Current Position Phase line should match /3.*Test Phase.*EXECUTING/; got ${JSON.stringify(posPhase)}`,
    );
  });

  test('Current Position Plan line shows "1 of N"', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    const posPlan = stateExtractField(result.content, 'Plan');
    assert.ok(
      /1 of 5/.test(posPlan || ''),
      `Current Position Plan line should match /1 of 5/; got ${JSON.stringify(posPlan)}`,
    );
  });

  test('Current Position Status line reflects Executing Phase N', () => {
    const result = transitionCore(firstTimeBody(), intent, deps);
    // 'Status' extraction returns the first match — which is the top-level
    // **Status:** line. The Current Position Status line is a different field
    // occurrence. Extract from the section to disambiguate.
    const { tokenizeHeadings } = require('../gsd-core/bin/lib/markdown-sectionizer.cjs');
    const body = result.content;
    const hs = tokenizeHeadings(body);
    const posIdx = hs.findIndex(h => h.level === 2 && /^current\s+position$/i.test(h.text));
    assert.notStrictEqual(posIdx, -1, 'Current Position section must exist');
    // Slice the section body and look for the Status line within it.
    const h = hs[posIdx];
    const lines = body.split('\n');
    const hl = lines[h.line - 1];
    const bodyStart = h.offset + hl.length + 1;
    let bodyEnd = body.length;
    for (let j = posIdx + 1; j < hs.length; j++) {
      if (hs[j].level >= 2) { bodyEnd = hs[j].offset - 1; break; }
    }
    const sectionBody = body.slice(bodyStart, bodyEnd);
    const sectionStatus = stateExtractField(sectionBody, 'Status');
    assert.ok(
      /Executing Phase\s+3/.test(sectionStatus || ''),
      `Current Position Status line should match /Executing Phase 3/; got ${JSON.stringify(sectionStatus)}`,
    );
  });
});

describe('ADR-1769 Phase 1: Current Position section mutation (resume path)', () => {
  const intent = { kind: 'beginPhase', phaseNumber: 3, phaseName: 'Test Phase', planCount: 5 };
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('Resume updates only the Last activity line in Current Position (preserves Plan, Phase, Status)', () => {
    const result = transitionCore(resumeBody(), intent, deps);
    assert.ok(result.updated.includes('Last activity (resume)') || result.updated.includes('Last Activity'),
      `resume should update Last activity; got ${JSON.stringify(result.updated)}`);
    // Plan line in Current Position should still say "2 of 5" (NOT reset to "1 of 5").
    const posPlan = stateExtractField(result.content, 'Plan');
    assert.ok(
      /2 of 5/.test(posPlan || ''),
      `resume should preserve Plan "2 of 5"; got ${JSON.stringify(posPlan)}`,
    );
  });
});

describe('ADR-1769 Phase 1: property tests (RULESET.TESTS.property-based-testing)', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('for any non-negative integer phaseNumber and any STATE.md body with a non-whitespace Status value, beginPhase produces content whose body Status carries "Executing Phase N"', () => {
    // Note: filters out whitespace-only statusSuffix because state-document.cjs's
    // bold stateReplaceField pattern uses greedy \s* that consumes the trailing
    // newline when the value is whitespace-only — a pre-existing bug surfaced
    // by this property test, not introduced by ADR-1769. Filed as a follow-up.
    fc.assert(
      fc.property(
        fc.integer({ min: 0, max: 999 }),
        fc.string({ minLength: 1 }).filter(s => s.trim().length > 0 && !s.includes('\u0000')),
        (phaseNum, statusSuffix) => {
          const input = `# Project State\n\n**Status:** ${statusSuffix}\n`;
          const result = transitionCore(
            input,
            { kind: 'beginPhase', phaseNumber: phaseNum, phaseName: null, planCount: null },
            deps,
          );
          const bodyStatus = stateExtractField(result.content, 'Status') || '';
          return new RegExp(`Executing Phase\\s+${phaseNum}\\b`).test(bodyStatus);
        },
      ),
      { numRuns: 100 },
    );
  });

  test('getFieldClassification own-property lookup always returns null or a valid {source, preservation} row', () => {
    const allowedSources = new Set(['body', 'disk', 'external', 'curated', 'free']);
    const allowedPreservation = new Set([
      'derive',
      'preserve-when-unchanged',
      'preserve-always',
      'preserve-if-placeholder',
      'clear',
    ]);
    fc.assert(
      fc.property(fc.string(), (s) => {
        const cls = getFieldClassification(s);
        if (cls === null) return true;
        return allowedSources.has(cls.source) && allowedPreservation.has(cls.preservation);
      }),
      { numRuns: 200 },
    );
  });
});

describe('ADR-1769 Phase 2: advancePlan transition', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('advances Current Plan from N to N+1 (legacy format)', () => {
    const input = [
      '# Project State',
      '',
      '**Current Plan:** 02',
      '**Total Plans in Phase:** 05',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-26',
      '',
      '## Current Position',
      '',
      'Plan: 2 of 5',
      'Status: Executing Phase 3',
      '',
    ].join('\n');
    const result = transitionCore(input, { kind: 'advancePlan' }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Plan'), '3');
    assert.strictEqual(result.data && result.data.advanced, true);
    assert.strictEqual(result.data && result.data.current_plan, 3);
    assert.strictEqual(result.data && result.data.total_plans, 5);
  });

  test('phase-complete branch when currentPlan >= totalPlans', () => {
    const input = [
      '# Project State',
      '',
      '**Current Plan:** 05',
      '**Total Plans in Phase:** 05',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-26',
      '',
    ].join('\n');
    const result = transitionCore(input, { kind: 'advancePlan' }, deps);
    assert.strictEqual(result.data && result.data.advanced, false);
    assert.strictEqual(result.data && result.data.reason, 'last_plan');
    assert.strictEqual(result.data && result.data.status, 'ready_for_verification');
  });

  test('error when plan fields are unparseable', () => {
    const input = '# Project State\n\nNo plan fields here.\n';
    const result = transitionCore(input, { kind: 'advancePlan' }, deps);
    assert.strictEqual(result.data && result.data.error, true);
    assert.deepStrictEqual(result.updated, []);
  });

  test('compound format: "Plan: 2 of 6" preserves compound shape', () => {
    const input = [
      '# Project State',
      '',
      '**Plan:** 2 of 6',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-26',
      '',
    ].join('\n');
    const result = transitionCore(input, { kind: 'advancePlan' }, deps);
    const plan = stateExtractField(result.content, 'Plan');
    assert.ok(/3 of 6/.test(plan || ''), `Plan should be "3 of 6"; got ${JSON.stringify(plan)}`);
    assert.strictEqual(result.data && result.data.advanced, true);
  });
});

describe('ADR-1769 Phase 2: advancePlan with frontmatter (#1255 pattern — codex review)', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('advances plan correctly when STATE.md has YAML frontmatter (body Status not YAML status)', () => {
    const input = [
      '---',
      'status: Executing Phase 3',
      'current_phase: "03"',
      '---',
      '',
      '# Project State',
      '',
      '**Current Plan:** 02',
      '**Total Plans in Phase:** 05',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-26',
      '',
      '## Current Position',
      '',
      'Plan: 2 of 5',
      'Status: Executing Phase 3',
      '',
    ].join('\n');
    const result = transitionCore(input, { kind: 'advancePlan' }, deps);
    // Body Current Plan must advance to 3.
    assert.strictEqual(stateExtractField(result.content, 'Current Plan'), '3');
    // Body Status must be updated (not the YAML status key).
    const bodyStatus = stateExtractField(result.content, 'Status');
    assert.ok(
      /Ready to execute/.test(bodyStatus || ''),
      `body Status should be "Ready to execute"; got ${JSON.stringify(bodyStatus)}`,
    );
    assert.strictEqual(result.data && result.data.advanced, true);
  });
});

// Shared fixture for completePhase: a STATE.md body mid-execution with the
// progress fields the cmdPhaseComplete transform touches. Mirrors the shape
// state.cts:buildStateFrontmatter emits.
function completePhaseBody() {
  return [
    '# Project State',
    '',
    '**Current Phase:** 3 of 5 (Old Name)',
    '**Current Phase Name:** Old Name',
    '**Current Plan:** 2',
    '**Status:** Executing Phase 3',
    '**Last Activity:** 2026-06-20',
    '**Last Activity Description:** mid-flight',
    '**Completed Phases:** 2',
    '**Total Phases:** 5',
    '**Progress:** 40%',
    'percent: 40',
    '',
  ].join('\n');
}

// A roadmap with a progress table: 3 of 5 phases Complete → deriveProgressFromRoadmap
// returns { completedPhases: 3, totalPhases: 5 }.
const ROADMAP_3_OF_5 = [
  '## Roadmap',
  '',
  '| Phase | Title | Status | Completed |',
  '| --- | --- | --- | --- |',
  '| 1 | A | Complete | 2026-01-01 |',
  '| 2 | B | Complete | 2026-02-01 |',
  '| 3 | C | Complete | 2026-03-01 |',
  '| 4 | D | In Progress | - |',
  '| 5 | E | Pending | - |',
  '',
].join('\n');

describe('ADR-1769 Phase 3: completePhase transition — body field updates', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress, roadmapProvider: () => ROADMAP_3_OF_5 };

  test('Current Phase advances to nextPhaseNum, preserving "of total" and appending the next name', () => {
    const intent = {
      kind: 'completePhase',
      phaseNum: '3',
      nextPhaseNum: '4',
      nextPhaseName: 'Design Phase',
      isLastPhase: false,
      planCount: 3,
      summaryCount: 3,
    };
    const result = transitionCore(completePhaseBody(), intent, deps);
    const cp = stateExtractField(result.content, 'Current Phase');
    assert.ok(
      /^4 of 5 \(Design Phase\)$/.test(cp || ''),
      `Current Phase should be "4 of 5 (Design Phase)"; got ${JSON.stringify(cp)}`,
    );
    assert.ok(result.updated.includes('Current Phase'));
  });

  test('Current Phase Name is set to nextPhaseName when provided', () => {
    const intent = {
      kind: 'completePhase',
      phaseNum: '3',
      nextPhaseNum: '4',
      nextPhaseName: 'Design Phase',
      isLastPhase: false,
      planCount: 3,
      summaryCount: 3,
    };
    const result = transitionCore(completePhaseBody(), intent, deps);
    assert.strictEqual(stateExtractField(result.content, 'Current Phase Name'), 'Design Phase');
  });

  test('Status becomes "Ready to plan" when not the last phase', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: 'Design Phase', isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Status'), 'Ready to plan');
  });

  test('Status becomes "Milestone complete" when isLastPhase is true', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '5', nextPhaseNum: null, nextPhaseName: null, isLastPhase: true, planCount: 2, summaryCount: 2 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Status'), 'Milestone complete');
  });

  test('Current Plan resets to "Not started"', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Current Plan'), 'Not started');
  });

  test('Last Activity Description carries transition narrative', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    assert.strictEqual(
      stateExtractField(result.content, 'Last Activity Description'),
      'Phase 3 complete, transitioned to Phase 4',
    );
  });

  test('Last Activity Description has no transition clause when there is no next phase', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '5', nextPhaseNum: null, nextPhaseName: null, isLastPhase: true, planCount: 2, summaryCount: 2 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Last Activity Description'), 'Phase 5 complete');
  });
});

describe('ADR-1769 Phase 3: completePhase progress derivation (roadmap)', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress, roadmapProvider: () => ROADMAP_3_OF_5 };

  test('Completed Phases is re-derived from the roadmap progress table', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Completed Phases'), '3');
  });

  test('Progress percent is recomputed and the inline percent: token is updated', () => {
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Progress'), '60%');
    assert.ok(/percent:\s*60/.test(result.content), `inline percent: token should be 60; content was:\n${result.content}`);
  });

  test('when roadmapProvider yields null, existing Completed Phases / Progress are preserved (no crash)', () => {
    const nullDeps = { clock: fixedClock, progressProvider: noProgress, roadmapProvider: () => null };
    const result = transitionCore(
      completePhaseBody(),
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      nullDeps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Completed Phases'), '2');
    assert.strictEqual(stateExtractField(result.content, 'Progress'), '40%');
  });
});

describe('ADR-1769 Phase 3: completePhase edge cases', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress, roadmapProvider: () => ROADMAP_3_OF_5 };

  test('falls back to the "Phase:" field when "Current Phase:" is absent (stateReplaceFieldWithFallback)', () => {
    const input = [
      '# Project State',
      '',
      'Phase: 3 of 5',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-20',
      '**Completed Phases:** 2',
      '**Total Phases:** 5',
      '**Progress:** 40%',
      '',
    ].join('\n');
    const result = transitionCore(
      input,
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    const phase = stateExtractField(result.content, 'Phase');
    assert.ok(/^4 of 5/.test(phase || ''), `Phase should advance to "4 of 5"; got ${JSON.stringify(phase)}`);
  });

  test('updates body Status, not the YAML status key, when frontmatter is present (#1255)', () => {
    const input = [
      '---',
      'status: executing',
      'current_phase: "3"',
      '---',
      '',
      '# Project State',
      '',
      '**Current Phase:** 3 of 5',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-20',
      '**Completed Phases:** 2',
      '**Total Phases:** 5',
      '**Progress:** 40%',
      '',
    ].join('\n');
    const result = transitionCore(
      input,
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    // Body Status line must read "Ready to plan".
    const bodyStatus = stateExtractField(result.content, 'Status');
    assert.strictEqual(bodyStatus, 'Ready to plan');
    // Frontmatter must remain a block and keep its YAML keys (not be mangled).
    assert.ok(/^---\r?\n[\s\S]*?\r?\n---/.test(result.content), 'frontmatter block must be preserved');
    const fmLine = result.content.split('\n').find((l) => /^status:/.test(l));
    assert.ok(fmLine && /executing/.test(fmLine), `YAML status key must be untouched; got ${JSON.stringify(fmLine)}`);
  });

  test('when nextPhaseName is absent and Current Phase had no "of total", value is the bare phase number', () => {
    const input = [
      '# Project State',
      '',
      '**Current Phase:** 3',
      '**Status:** Executing Phase 3',
      '**Last Activity:** 2026-06-20',
      '**Completed Phases:** 2',
      '**Total Phases:** 5',
      '**Progress:** 40%',
      '',
    ].join('\n');
    const result = transitionCore(
      input,
      { kind: 'completePhase', phaseNum: '3', nextPhaseNum: '4', nextPhaseName: null, isLastPhase: false, planCount: 3, summaryCount: 3 },
      deps,
    );
    assert.strictEqual(stateExtractField(result.content, 'Current Phase'), '4');
  });
});

// ADR-1769 Phase 4: plannedPhase + milestoneSwitch

function plannedPhaseBody() {
  return [
    '# Project State',
    '',
    '**Status:** Planning',
    '**Total Plans in Phase:** 0',
    '**Last Activity:** 2026-06-20',
    '**Last Activity Description:** previous planning',
    '',
    '## Current Position',
    '',
    'Phase: 3 (Test Phase) — EXECUTING',
    'Plan: —',
    'Status: Executing Phase 3',
    'Last activity: 2026-06-20 — mid-flight',
    '',
  ].join('\n');
}

describe('ADR-1769 Phase 4: plannedPhase transition — body field updates', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress };

  test('Status advances to "Ready to execute" when the existing value is a template default (Planning)', () => {
    const result = transitionCore(plannedPhaseBody(), { kind: 'plannedPhase', phaseNumber: 3, planCount: 4 }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Status'), 'Ready to execute');
    assert.ok(result.updated.includes('Status'));
  });

  test('Total Plans in Phase is set to planCount', () => {
    const result = transitionCore(plannedPhaseBody(), { kind: 'plannedPhase', phaseNumber: 3, planCount: 4 }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Total Plans in Phase'), '4');
    assert.ok(result.updated.includes('Total Plans in Phase'));
  });

  test('Last Activity is refreshed to clock.today() when the existing value is a date (template default)', () => {
    const result = transitionCore(plannedPhaseBody(), { kind: 'plannedPhase', phaseNumber: 3, planCount: 4 }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Last Activity'), '2026-06-27');
  });

  test('Last Activity Description carries the planning-complete narrative', () => {
    const result = transitionCore(plannedPhaseBody(), { kind: 'plannedPhase', phaseNumber: 3, planCount: 4 }, deps);
    assert.strictEqual(
      stateExtractField(result.content, 'Last Activity Description'),
      'Phase 3 planning complete — 4 plans ready',
    );
  });

  test('Current Position Status + Last activity are updated', () => {
    const result = transitionCore(plannedPhaseBody(), { kind: 'plannedPhase', phaseNumber: 3, planCount: 4 }, deps);
    assert.ok(result.updated.includes('Current Position'),
      `updated should include Current Position; got ${JSON.stringify(result.updated)}`);
    // The Current Position section should now carry the planning-complete narrative.
    assert.ok(/Phase 3 planning complete/.test(result.content));
  });

  test('executor-authored Status is preserved (Knuth invariant — non-template value not overwritten)', () => {
    const custom = plannedPhaseBody().replace('**Status:** Planning', '**Status:** Awaiting human design review');
    const result = transitionCore(custom, { kind: 'plannedPhase', phaseNumber: 3, planCount: 4 }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Status'), 'Awaiting human design review');
    assert.ok(!result.updated.includes('Status'),
      `Status must not be in updated for an executor-authored value; got ${JSON.stringify(result.updated)}`);
  });

  test('planCount=null leaves Total Plans in Phase untouched', () => {
    const result = transitionCore(plannedPhaseBody(), { kind: 'plannedPhase', phaseNumber: 3, planCount: null }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Total Plans in Phase'), '0');
    assert.ok(!result.updated.includes('Total Plans in Phase'));
  });

  test('frontmatter is preserved and body Status (not YAML status) is updated (#1255)', () => {
    const input = [
      '---',
      'status: planning',
      '---',
      '',
      '# Project State',
      '',
      '**Status:** Planning',
      '**Total Plans in Phase:** 0',
      '**Last Activity:** 2026-06-20',
      '**Last Activity Description:** prev',
      '',
      '## Current Position',
      '',
      'Status: Executing Phase 3',
      'Last activity: 2026-06-20 — mid',
      '',
    ].join('\n');
    const result = transitionCore(input, { kind: 'plannedPhase', phaseNumber: 3, planCount: 2 }, deps);
    assert.strictEqual(stateExtractField(result.content, 'Status'), 'Ready to execute');
    assert.ok(/^---\r?\n[\s\S]*?\r?\n---/.test(result.content), 'frontmatter block preserved');
  });
});

describe('ADR-1769 Phase 4: milestoneSwitch transition — milestone reset', () => {
  const deps = { clock: fixedClock, progressProvider: noProgress };

  function milestoneBody() {
    return [
      '---',
      'gsd_state_version: 1.0',
      'milestone: v1.0',
      'milestone_name: Old Milestone',
      'status: executing',
      'current_phase: "3"',
      'progress:',
      '  total_phases: 5',
      '  completed_phases: 2',
      '  percent: 40',
      '---',
      '',
      '# Project State',
      '',
      '## Current Position',
      '',
      'Phase: 3 — EXECUTING',
      'Plan: 2 of 5',
      'Status: Executing Phase 3',
      'Last activity: 2026-06-20 — mid-flight',
      '',
    ].join('\n');
  }

  test('frontmatter milestone + milestone_name are reset to the new version', () => {
    const result = transitionCore(milestoneBody(), { kind: 'milestoneSwitch', version: 'v2.0', name: 'New Milestone' }, deps);
    const fmLine = (key) => result.content.split('\n').find((l) => new RegExp(`^${key}:`).test(l));
    assert.strictEqual(fmLine('milestone'), 'milestone: v2.0');
    assert.strictEqual(fmLine('milestone_name'), 'milestone_name: New Milestone');
  });

  test('frontmatter status resets to planning and progress resets to zero', () => {
    const result = transitionCore(milestoneBody(), { kind: 'milestoneSwitch', version: 'v2.0', name: 'New Milestone' }, deps);
    assert.strictEqual(result.content.split('\n').find((l) => /^status:/.test(l)), 'status: planning');
    assert.ok(/total_phases:\s*0/.test(result.content), 'total_phases should reset to 0');
    assert.ok(/completed_phases:\s*0/.test(result.content), 'completed_phases should reset to 0');
    assert.ok(/percent:\s*0/.test(result.content), 'percent should reset to 0');
  });

  test('gsd_state_version is preserved across the reset', () => {
    const result = transitionCore(milestoneBody(), { kind: 'milestoneSwitch', version: 'v2.0', name: 'New Milestone' }, deps);
    assert.ok(/gsd_state_version:\s*1\.0/.test(result.content), 'gsd_state_version must be preserved');
  });

  test('Current Position section is reset to "Not started (defining requirements)"', () => {
    const result = transitionCore(milestoneBody(), { kind: 'milestoneSwitch', version: 'v2.0', name: 'New Milestone' }, deps);
    assert.ok(/Phase: Not started \(defining requirements\)/.test(result.content));
    assert.ok(/Status: Defining requirements/.test(result.content));
    assert.ok(new RegExp(`Last activity: 2026-06-27 — Milestone v2.0 started`).test(result.content));
  });

  test('Accumulated Context / body content outside Current Position is preserved', () => {
    const input = milestoneBody() +
      '\n## Accumulated Context\n\n- An important decision we must keep.\n';
    const result = transitionCore(input, { kind: 'milestoneSwitch', version: 'v2.0', name: 'New Milestone' }, deps);
    assert.ok(/An important decision we must keep/.test(result.content),
      'Accumulated Context must survive the milestone reset');
  });

  test('blank name falls back to the "milestone" placeholder', () => {
    const result = transitionCore(milestoneBody(), { kind: 'milestoneSwitch', version: 'v2.0', name: '' }, deps);
    assert.strictEqual(
      result.content.split('\n').find((l) => /^milestone_name:/.test(l)),
      'milestone_name: milestone',
    );
  });
});