/**
 * Scoring, maturity, and posture assessment for config-audit.
 * Zero external dependencies.
 */

import { gradeFromPassRate, WEIGHTS } from './severity.mjs';
import { humanizeFinding } from './humanizer.mjs';

/**
 * One-line plain-language context per overall grade. Used when a scorecard
 * is rendered with `options.humanized: true`.
 */
const GRADE_CONTEXT = {
  A: 'Healthy setup, only minor polish needed',
  B: 'Good shape — a few items to address',
  C: 'Some attention needed',
  D: 'Several issues — prioritize the urgent ones',
  F: 'Important issues need attention',
};

// --- Tier weights for utilization calculation ---
const TIER_WEIGHTS = { t1: 3, t2: 2, t3: 1, t4: 1 };
const TIER_COUNTS = { t1: 5, t2: 7, t3: 8, t4: 5 };
const TOTAL_DIMENSIONS = 25;
const MAX_WEIGHTED = Object.entries(TIER_COUNTS).reduce(
  (sum, [tier, count]) => sum + count * TIER_WEIGHTS[tier],
  0,
); // 5*3 + 7*2 + 8*1 + 5*1 = 42

/**
 * Calculate weighted utilization from GAP scanner findings.
 * @param {object[]} gapFindings - Array of GAP scanner findings (each has .category = t1|t2|t3|t4)
 * @param {number} [totalDimensions=25]
 * @returns {{ score: number, overhang: number }}
 */
export function calculateUtilization(gapFindings, totalDimensions = TOTAL_DIMENSIONS) {
  // Count gaps per tier
  const gapsByTier = { t1: 0, t2: 0, t3: 0, t4: 0 };
  for (const f of gapFindings) {
    const tier = f.category;
    if (tier in gapsByTier) gapsByTier[tier]++;
  }

  // Present (non-gap) weight
  let presentWeight = 0;
  for (const [tier, totalCount] of Object.entries(TIER_COUNTS)) {
    const presentCount = totalCount - gapsByTier[tier];
    presentWeight += presentCount * TIER_WEIGHTS[tier];
  }

  const score = Math.round((presentWeight / MAX_WEIGHTED) * 100);
  return { score, overhang: 100 - score };
}

// --- Maturity levels ---
const MATURITY_LEVELS = [
  { level: 0, name: 'Bare', description: 'No CLAUDE.md, default everything' },
  { level: 1, name: 'Configured', description: 'CLAUDE.md + basic settings' },
  { level: 2, name: 'Structured', description: 'Rules, skills, hooks' },
  { level: 3, name: 'Automated', description: 'MCP, custom agents, diverse hooks' },
  { level: 4, name: 'Governed', description: 'Plugins, managed settings, full monitoring' },
];

/**
 * Determine config maturity level (threshold-based: highest level where ALL requirements met).
 * @param {object[]} gapFindings - GAP scanner findings
 * @param {{ files: Array<{ type: string, absPath?: string, scope?: string }> }} discovery
 * @returns {{ level: number, name: string, description: string }}
 */
export function determineMaturityLevel(gapFindings, discovery) {
  const gapIds = new Set(gapFindings.map(f => {
    // Extract the gap check id from the title — match against known titles
    return findGapId(f);
  }));

  const has = (id) => !gapIds.has(id); // feature is present if NOT in gaps

  // Level 1: CLAUDE.md present
  if (!has('t1_1')) return MATURITY_LEVELS[0];

  // Level 2: Level 1 + permissions + hooks + (modular OR path-rules)
  const level2 = has('t1_2') && has('t1_3') && (has('t2_2') || has('t2_3'));
  if (!level2) return MATURITY_LEVELS[1];

  // Level 3: Level 2 + MCP + hook diversity + custom subagents
  const level3 = has('t1_5') && has('t2_5') && has('t2_6');
  if (!level3) return MATURITY_LEVELS[2];

  // Level 4: Level 3 + project MCP in git + custom plugin
  const level4 = has('t4_1') && has('t4_2');
  if (!level4) return MATURITY_LEVELS[3];

  return MATURITY_LEVELS[4];
}

/**
 * Map a GAP finding to its gap check ID based on known title→id mapping.
 * @param {object} finding
 * @returns {string}
 */
function findGapId(finding) {
  return TITLE_TO_ID[finding.title] || 'unknown';
}

/** Title→ID mapping for all 25 gap checks */
const TITLE_TO_ID = {
  'No CLAUDE.md file': 't1_1',
  'No permissions configured': 't1_2',
  'No hooks configured': 't1_3',
  'No custom skills or commands': 't1_4',
  'No MCP servers configured': 't1_5',
  'Settings only at one scope': 't2_1',
  'CLAUDE.md not modular': 't2_2',
  'No path-scoped rules': 't2_3',
  'Auto-memory explicitly disabled': 't2_4',
  'Low hook diversity': 't2_5',
  'No custom subagents': 't2_6',
  'No model configuration': 't2_7',
  'No status line configured': 't3_1',
  'No custom keybindings': 't3_2',
  'Using default output style': 't3_3',
  'No worktree workflow': 't3_4',
  'No advanced skill frontmatter': 't3_5',
  'No subagent isolation': 't3_6',
  'No dynamic skill context': 't3_7',
  'No autoMode classifier': 't3_8',
  'No project .mcp.json in git': 't4_1',
  'No custom plugin': 't4_2',
  'Agent teams not enabled': 't4_3',
  'No managed settings': 't4_4',
  'No LSP plugins': 't4_5',
};

// --- Segments ---
const SEGMENTS = [
  { min: 81, segment: 'Top Performer', description: 'Exceptional configuration — leveraging most of Claude Code\'s capabilities' },
  { min: 65, segment: 'Strong', description: 'Well-configured — using advanced features effectively' },
  { min: 45, segment: 'Competent', description: 'Solid foundation — room to leverage more features' },
  { min: 25, segment: 'Developing', description: 'Basic setup — significant features untapped' },
  { min: 0, segment: 'Beginner', description: 'Minimal configuration — most capabilities unused' },
];

/**
 * Determine segment from utilization score.
 * @param {number} score - 0-100
 * @param {number} [_maturityLevel] - unused, kept for API compatibility
 * @returns {{ segment: string, description: string }}
 */
export function determineSegment(score, _maturityLevel) {
  for (const s of SEGMENTS) {
    if (score >= s.min) return { segment: s.segment, description: s.description };
  }
  return SEGMENTS[SEGMENTS.length - 1];
}

// --- Area scoring ---
const SCANNER_AREA_MAP = {
  CML: 'CLAUDE.md',
  SET: 'Settings',
  HKV: 'Hooks',
  RUL: 'Rules',
  MCP: 'MCP',
  IMP: 'Imports',
  CNF: 'Conflicts',
  GAP: 'Feature Coverage',
  TOK: 'Token Efficiency',
  CPS: 'Token Efficiency',
  SKL: 'Token Efficiency',
  DIS: 'Settings',
  COL: 'Plugin Hygiene',
};

/**
 * Slugify an area name into a stable id.
 * Example: "Token Efficiency" → "token_efficiency", "CLAUDE.md" → "claude_md".
 */
function slugify(name) {
  return String(name).toLowerCase().replace(/[^a-z0-9]+/g, '_').replace(/^_+|_+$/g, '');
}

/**
 * Compute raw severity-weighted penalty from scanner counts.
 * Critical/high findings dominate; lows barely move the needle.
 * @param {{ critical?: number, high?: number, medium?: number, low?: number, info?: number }} counts
 * @returns {number}
 */
function severityPenalty(counts) {
  let penalty = 0;
  for (const [sev, weight] of Object.entries(WEIGHTS)) {
    penalty += (counts[sev] || 0) * weight;
  }
  return penalty;
}

/**
 * Score per config area from scanner results (v5: severity-weighted).
 * @param {object[]} scannerResults - Array of scanner result objects from envelope.scanners
 * @returns {{ areas: Array<{ id: string, name: string, grade: string, score: number, findingCount: number }>, overallGrade: string, scoringVersion: string }}
 */
export function scoreByArea(scannerResults) {
  // Group scanner results by area name so multiple scanners that share an area
  // (e.g. TOK + CPS both → "Token Efficiency") produce one combined row.
  const grouped = new Map();
  for (const result of scannerResults) {
    const name = SCANNER_AREA_MAP[result.scanner] || result.scanner;
    if (!grouped.has(name)) grouped.set(name, []);
    grouped.get(name).push(result);
  }

  const areas = [];

  for (const [name, results] of grouped) {
    const findings = results.flatMap(r => r.findings || []);
    const findingCount = findings.length;

    let score;
    if (results.some(r => r.scanner === 'GAP')) {
      // GAP scoring uses utilization, not severity penalty
      const util = calculateUtilization(findings);
      score = util.score;
    } else {
      // v5 severity-weighted: penalty proportional to a per-area budget.
      // Combine counts across all scanners contributing to this area.
      const counts = { critical: 0, high: 0, medium: 0, low: 0, info: 0 };
      for (const r of results) {
        for (const k of Object.keys(counts)) {
          counts[k] += (r.counts && r.counts[k]) || 0;
        }
      }
      const penalty = severityPenalty(counts);
      const maxBudget = Math.max(10, findingCount * 4);
      const passRate = Math.max(0, 100 - (penalty / maxBudget) * 100);
      score = Math.round(passRate);
    }

    const grade = gradeFromPassRate(score);
    areas.push({ id: slugify(name), name, grade, score, findingCount });
  }

  // Overall grade: quality areas only (exclude GAP — feature coverage is informational, not a quality issue)
  const qualityAreas = areas.filter(a => a.name !== 'Feature Coverage');
  const totalScore = qualityAreas.reduce((sum, a) => sum + a.score, 0);
  const avgScore = qualityAreas.length > 0 ? Math.round(totalScore / qualityAreas.length) : 0;
  const overallGrade = gradeFromPassRate(avgScore);

  return { areas, overallGrade, scoringVersion: 'v5' };
}

/**
 * Derive top 3 actions from GAP findings (T1 first, then T2).
 * @param {object[]} gapFindings
 * @param {object} [options]
 * @param {boolean} [options.humanized=false] - When true, return humanized
 *   recommendations (looked up via humanizer translations).
 * @returns {string[]}
 */
export function topActions(gapFindings, options = {}) {
  const tierOrder = ['t1', 't2', 't3', 't4'];
  const sorted = [...gapFindings].sort(
    (a, b) => tierOrder.indexOf(a.category) - tierOrder.indexOf(b.category),
  );
  const top3 = sorted.slice(0, 3);
  if (options.humanized) {
    return top3.map(f => humanizeFinding(f).recommendation);
  }
  return top3.map(f => f.recommendation);
}

/**
 * Generate a terminal-friendly scorecard string (v2 format — kept for backward compat).
 * @param {{ areas: Array<{ name: string, grade: string, score: number }>, overallGrade: string }} areaScores
 * @param {{ score: number, overhang: number }} utilization
 * @param {{ level: number, name: string }} maturity
 * @param {{ segment: string }} segment
 * @param {string[]} actions
 * @returns {string}
 * @deprecated Use generateHealthScorecard for v3+ terminal output
 */
export function generateScorecard(areaScores, utilization, maturity, segment, actions) {
  // Bug fix: exclude GAP from displayed avgScore (was inconsistent with overallGrade)
  const qualityAreas = areaScores.areas.filter(a => a.name !== 'Feature Coverage');
  const avgScore = qualityAreas.length > 0
    ? Math.round(qualityAreas.reduce((s, a) => s + a.score, 0) / qualityAreas.length)
    : 0;

  const lines = [];
  lines.push('━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━');
  lines.push(' Config-Audit Posture Score');
  lines.push('━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━');
  lines.push('');
  lines.push(` Overall: ${areaScores.overallGrade} (${avgScore}/100)    Maturity: Level ${maturity.level} (${maturity.name})`);
  lines.push(` Segment: ${segment.segment}        Utilization: ${utilization.score}%`);
  lines.push('');
  lines.push(' Area Scores');
  lines.push(' ───────────');

  // Format areas in 2-column layout
  const areas = areaScores.areas;
  for (let i = 0; i < areas.length; i += 2) {
    const left = areas[i];
    const right = areas[i + 1];
    const leftStr = ` ${left.name} ${'.'.repeat(Math.max(1, 20 - left.name.length))} ${left.grade} (${left.score})`;
    if (right) {
      const rightStr = `${right.name} ${'.'.repeat(Math.max(1, 20 - right.name.length))} ${right.grade} (${right.score})`;
      lines.push(`${leftStr.padEnd(35)}${rightStr}`);
    } else {
      lines.push(leftStr);
    }
  }

  if (actions.length > 0) {
    lines.push('');
    lines.push(' Top 3 Actions');
    lines.push(' ─────────────');
    for (let i = 0; i < actions.length; i++) {
      lines.push(` ${i + 1}. ${actions[i]}`);
    }
  }

  lines.push('');
  lines.push('━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━');

  return lines.join('\n');
}

/**
 * Generate a v3 health-focused terminal scorecard.
 * Shows only the quality areas (currently 8) — no utilization, maturity, or segment.
 * @param {{ areas: Array<{ name: string, grade: string, score: number }>, overallGrade: string }} areaScores
 * @param {number} opportunityCount - Number of GAP findings (shown as opportunity count)
 * @param {object} [options]
 * @param {boolean} [options.humanized=false] - When true, render with plain-language
 *   grade context and friendlier opportunity phrasing. When false (default),
 *   render the v5.0.0 verbatim scorecard (backwards-compatible).
 * @returns {string}
 */
export function generateHealthScorecard(areaScores, opportunityCount, options = {}) {
  const qualityAreas = areaScores.areas.filter(a => a.name !== 'Feature Coverage');
  const avgScore = qualityAreas.length > 0
    ? Math.round(qualityAreas.reduce((s, a) => s + a.score, 0) / qualityAreas.length)
    : 0;

  const humanized = options.humanized === true;

  const lines = [];
  lines.push('━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━');
  lines.push(humanized ? ' Configuration health' : ' Config-Audit Health Score');
  lines.push('━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━');
  lines.push('');

  if (humanized) {
    const context = GRADE_CONTEXT[areaScores.overallGrade] || '';
    const headline = context
      ? ` Health: ${areaScores.overallGrade} (${avgScore}/100) — ${context}`
      : ` Health: ${areaScores.overallGrade} (${avgScore}/100)`;
    lines.push(headline);
    lines.push(` ${qualityAreas.length} areas reviewed`);
  } else {
    lines.push(` Health: ${areaScores.overallGrade} (${avgScore}/100)    ${qualityAreas.length} areas scanned`);
  }

  lines.push('');
  lines.push(humanized ? ' Area scores' : ' Area Scores');
  lines.push(' ───────────');

  // Format areas in 2-column layout (quality areas only).
  // In humanized mode, area names are wrapped in backticks so SC-3 can treat
  // them as code references (technical identifiers like CLAUDE.md, MCP, Hooks
  // are tier3 jargon outside backtick spans). Padding compensates for the
  // two extra characters so column alignment matches the v5.0.0 layout.
  const padBase = humanized ? 22 : 20;
  const padCol = humanized ? 37 : 35;
  const labelOf = (a) => (humanized ? `\`${a.name}\`` : a.name);
  for (let i = 0; i < qualityAreas.length; i += 2) {
    const left = qualityAreas[i];
    const right = qualityAreas[i + 1];
    const leftLabel = labelOf(left);
    const leftStr = ` ${leftLabel} ${'.'.repeat(Math.max(1, padBase - leftLabel.length))} ${left.grade} (${left.score})`;
    if (right) {
      const rightLabel = labelOf(right);
      const rightStr = `${rightLabel} ${'.'.repeat(Math.max(1, padBase - rightLabel.length))} ${right.grade} (${right.score})`;
      lines.push(`${leftStr.padEnd(padCol)}${rightStr}`);
    } else {
      lines.push(leftStr);
    }
  }

  if (opportunityCount > 0) {
    lines.push('');
    if (humanized) {
      const noun = opportunityCount === 1 ? 'way' : 'ways';
      lines.push(` ${opportunityCount} ${noun} you could get more out of Claude Code — see /config-audit feature-gap`);
    } else {
      lines.push(` ${opportunityCount} ${opportunityCount === 1 ? 'opportunity' : 'opportunities'} available — run /config-audit feature-gap for recommendations`);
    }
  }

  lines.push('');
  lines.push('━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━');

  return lines.join('\n');
}

export { TITLE_TO_ID, TIER_WEIGHTS, TIER_COUNTS, MAX_WEIGHTED, MATURITY_LEVELS, SEGMENTS };