/**
 * chooseNarrative.ts
 * Generates 3 candidate positioning headlines and selects the strongest one.
 * The positioning angle drives the entire carousel's tone and framing.
 */

import type {
  CandidateProfile,
  FitAnalysis,
  HighlightCandidate,
  PositioningAngle,
  PositioningMode,
  TargetRoleProfile,
} from '../schema/carouselSchema';

// ---------------------------------------------------------------------------
// Headline template generators by mode
// ---------------------------------------------------------------------------

function buildRecruiterHeadlines(
  candidate: CandidateProfile,
  role: TargetRoleProfile,
  fit: FitAnalysis
): string[] {
  const title = role.title || 'Product Analyst';
  const mostRecentRole = candidate.roles[0]?.title || 'Analyst';
  const topAlignment = fit.strongestAlignments[0]?.area || '';
  const secondAlignment = fit.strongestAlignments[1]?.area || '';
  const domain = fit.strongestAlignments[0] ? role.domainClues[0] || '' : '';

  const headlines = [
    // Clarity + fit signal headline
    `${mostRecentRole} with proven track record in ${topAlignment}${secondAlignment ? ` and ${secondAlignment}` : ''} — ready to drive impact as ${title}`,
    // Impact-led headline — no raw metric injected, keep it clean
    `${title}-ready: ${topAlignment ? `${topAlignment} expertise` : 'cross-functional leader'} with measurable business outcomes`,
    // Domain-specific fit headline
    `${mostRecentRole} bringing ${domain ? `${domain} domain depth` : 'deep technical expertise'} and strong execution to ${title} role`,
  ];

  return headlines.filter((h) => h.length > 10 && h.length < 160);
}

function buildHiringManagerHeadlines(
  candidate: CandidateProfile,
  role: TargetRoleProfile,
  fit: FitAnalysis
): string[] {
  const mostRecentRole = candidate.roles[0]?.title || 'Engineer';
  const topTool = candidate.tools.slice(0, 2).join(' + ') || 'modern stack';
  const topProblem = role.themes[0] || 'complex systems';
  const ownershipVerbs = candidate.ownershipIndicators.slice(0, 2).join(' and ');

  const headlines = [
    // Technical credibility headline
    `${mostRecentRole} who ${ownershipVerbs || 'builds and ships'} — experienced with ${topTool} at scale`,
    // Problem-solver framing
    `${topProblem ? `${capitalize(topProblem)}-focused` : 'Systems-minded'} ${mostRecentRole.toLowerCase()} — ${fit.bestFitStory.split(':')[1]?.trim() || 'strong execution track record'}`,
    // Technical stack + outcomes
    `${mostRecentRole} who solves ${topProblem || 'hard technical problems'} — ${topTool ? `${topTool} practitioner` : 'strong generalist'}`,
  ];

  return headlines.filter((h) => h.length > 10 && h.length < 160);
}

function buildPersonalBrandHeadlines(
  candidate: CandidateProfile,
  role: TargetRoleProfile,
  fit: FitAnalysis
): string[] {
  const mostRecentRole = candidate.roles[0]?.title || 'Professional';
  const uniqueSignal = candidate.metrics[0] || fit.bestAchievements[0]?.split(' ').slice(0, 5).join(' ') || '';
  const topAlignment = fit.strongestAlignments[0]?.area || '';

  const headlines = [
    // Distinctive identity statement
    `The ${topAlignment ? `${topAlignment}-first` : 'results-first'} ${mostRecentRole.toLowerCase()} your company needs right now`,
    // Bold claim
    `Not just a ${mostRecentRole.toLowerCase()} — a ${role.themes[0] || 'high-impact'} operator who ships and scales`,
    // Memorable framing
    `${uniqueSignal ? `${uniqueSignal}` : 'Measurable results'} — that's what a great ${mostRecentRole.toLowerCase()} looks like`,
  ];

  return headlines.filter((h) => h.length > 10 && h.length < 160);
}

// ---------------------------------------------------------------------------
// Headline scoring
// ---------------------------------------------------------------------------

interface ScoredHeadline {
  headline: string;
  fitScore: number;
  clarityScore: number;
  distinctivenessScore: number;
  credibilityScore: number;
  compositeScore: number;
}

function scoreHeadline(
  headline: string,
  candidate: CandidateProfile,
  role: TargetRoleProfile,
  fit: FitAnalysis,
  mode: PositioningMode
): ScoredHeadline {
  const lower = headline.toLowerCase();
  let fitScore = 5;
  let clarityScore = 5;
  let distinctivenessScore = 5;
  let credibilityScore = 5;

  // Fit score — does the headline mention role-relevant terms?
  const roleTerms = [...role.requiredSkills, ...role.themes, ...role.domainClues];
  const roleTermMatches = roleTerms.filter((t) => lower.includes(t.toLowerCase())).length;
  fitScore = Math.min(5 + roleTermMatches * 2, 10);

  // Clarity score — penalize very long or vague headlines
  const wordCount = headline.split(/\s+/).length;
  if (wordCount <= 12) clarityScore = 9;
  else if (wordCount <= 18) clarityScore = 7;
  else if (wordCount <= 25) clarityScore = 5;
  else clarityScore = 3;

  // Penalize vague/generic phrases
  if (/results-oriented|passionate|self-starter|dynamic|innovative/i.test(headline)) {
    clarityScore -= 2;
  }

  // Distinctiveness — does it avoid pure job title repetition?
  if (lower.includes(role.title.toLowerCase()) && wordCount < 8) {
    distinctivenessScore = 3; // Just repeating the title
  } else if (/\b(who|that|with proven|ready to|bringing|not just)\b/i.test(headline)) {
    distinctivenessScore = 8; // Has a distinctive framing device
  }

  // Credibility — can we trace the claim to the resume?
  const candidateTerms = [
    ...candidate.tools,
    ...candidate.ownershipIndicators,
    ...candidate.domains,
  ];
  const credibleTerms = candidateTerms.filter((t) => lower.includes(t.toLowerCase())).length;
  credibilityScore = Math.min(4 + credibleTerms * 2, 10);

  // Mode-specific weights
  let composite: number;
  if (mode === 'recruiter') {
    composite = fitScore * 0.35 + clarityScore * 0.35 + distinctivenessScore * 0.15 + credibilityScore * 0.15;
  } else if (mode === 'hiring-manager') {
    composite = fitScore * 0.3 + clarityScore * 0.2 + distinctivenessScore * 0.2 + credibilityScore * 0.3;
  } else {
    // personal-brand
    composite = fitScore * 0.2 + clarityScore * 0.25 + distinctivenessScore * 0.35 + credibilityScore * 0.2;
  }

  return {
    headline,
    fitScore: Math.max(0, Math.min(10, Math.round(fitScore * 10) / 10)),
    clarityScore: Math.max(0, Math.min(10, Math.round(clarityScore * 10) / 10)),
    distinctivenessScore: Math.max(0, Math.min(10, Math.round(distinctivenessScore * 10) / 10)),
    credibilityScore: Math.max(0, Math.min(10, Math.round(credibilityScore * 10) / 10)),
    compositeScore: Math.max(0, Math.min(10, Math.round(composite * 10) / 10)),
  };
}

// ---------------------------------------------------------------------------
// Subheading generator
// ---------------------------------------------------------------------------

function generateSubheading(
  chosen: ScoredHeadline,
  candidate: CandidateProfile,
  role: TargetRoleProfile,
  fit: FitAnalysis,
  mode: PositioningMode
): string {
  const topAchievement = fit.bestAchievements[0] || '';
  const topTool = candidate.tools[0] || '';
  const topAlignment = fit.strongestAlignments[0]?.area || '';

  if (mode === 'recruiter') {
    return `Open to ${role.title} opportunities — ${topAlignment ? `${topAlignment} specialist` : 'results-driven professional'} with${topAchievement ? ` a track record of measurable impact` : ` deep domain expertise`}.`;
  } else if (mode === 'hiring-manager') {
    return `${topTool ? `${capitalize(topTool)} practitioner` : 'Technical practitioner'} focused on building systems that scale — ${fit.strongestAlignments.length} strong alignment areas with ${role.title}.`;
  } else {
    return `Sharing the systems, strategies, and lessons that built ${fit.bestAchievements.length > 0 ? 'real results' : 'a real career'} — and why it matters for ${role.title}.`;
  }
}

// ---------------------------------------------------------------------------
// Main chooser
// ---------------------------------------------------------------------------

/**
 * Generate 3 positioning headlines and return the best-scored PositioningAngle.
 */
export function choosePositioningAngle(
  candidate: CandidateProfile,
  role: TargetRoleProfile,
  fit: FitAnalysis,
  mode: PositioningMode
): PositioningAngle {
  // Generate mode-appropriate headlines
  let headlines: string[];
  if (mode === 'recruiter') {
    headlines = buildRecruiterHeadlines(candidate, role, fit);
  } else if (mode === 'hiring-manager') {
    headlines = buildHiringManagerHeadlines(candidate, role, fit);
  } else {
    headlines = buildPersonalBrandHeadlines(candidate, role, fit);
  }

  // Fallback if generator returned fewer than 3
  while (headlines.length < 3) {
    headlines.push(`${candidate.roles[0]?.title || 'Professional'} targeting ${role.title} — strong fit across ${fit.strongestAlignments.length} key areas`);
  }

  // Score all candidates
  const scored = headlines.map((h) => scoreHeadline(h, candidate, role, fit, mode));
  scored.sort((a, b) => b.compositeScore - a.compositeScore);

  const best = scored[0];
  const subheading = generateSubheading(best, candidate, role, fit, mode);

  const rationale = `Selected over ${scored.length - 1} alternatives. Fit: ${best.fitScore}/10, Clarity: ${best.clarityScore}/10, Distinctiveness: ${best.distinctivenessScore}/10, Credibility: ${best.credibilityScore}/10.`;

  return {
    headline: best.headline,
    subheading,
    rationale,
    mode,
    fitScore: best.fitScore,
    clarityScore: best.clarityScore,
    distinctivenessScore: best.distinctivenessScore,
    credibilityScore: best.credibilityScore,
    compositeScore: best.compositeScore,
  };
}

// ---------------------------------------------------------------------------
// Helper
// ---------------------------------------------------------------------------

function capitalize(str: string): string {
  if (!str) return '';
  return str.charAt(0).toUpperCase() + str.slice(1);
}