/**
 * buildOutline.ts
 * Generates the slide outline (structure + intent) from fit analysis, highlights, and positioning.
 * This is the planning stage before copy is written.
 */

import type {
  FitAnalysis,
  HighlightCandidate,
  PositioningAngle,
  SlideOutline,
  SlideTemplateType,
} from '../schema/carouselSchema';

// ---------------------------------------------------------------------------
// Default 7-slide structure
// ---------------------------------------------------------------------------

interface SlideBlueprint {
  templateType: SlideTemplateType;
  intent: string;
  pullHighlight: boolean;   // Whether to assign a highlight reference
  pullPositioning: boolean; // Whether to reference the positioning angle
}

const DEFAULT_SLIDE_STRUCTURE: SlideBlueprint[] = [
  {
    templateType: 'hook',
    intent: 'Identity hook: powerful recruiter-facing headline that stops the scroll. Not a generic title page — it must convey the positioning angle in a single punchy statement.',
    pullHighlight: false,
    pullPositioning: true,
  },
  {
    templateType: 'fit',
    intent: 'Why this candidate fits this role: present 3 concise strength areas that map directly to the JD. Each card should name a skill/theme and connect it to a real experience.',
    pullHighlight: false,
    pullPositioning: false,
  },
  {
    templateType: 'proof',
    intent: 'Signature proof slide: the single strongest role-relevant achievement. Lead with the metric or outcome. Give just enough context to make it credible.',
    pullHighlight: true,
    pullPositioning: false,
  },
  {
    templateType: 'proof',
    intent: 'Supporting proof slide: second strongest achievement. Contrast with slide 3 — different skill area, different time period, or different scale of impact.',
    pullHighlight: true,
    pullPositioning: false,
  },
  {
    templateType: 'workstyle',
    intent: 'How they work: operational or capability pattern. Not an achievement — a working philosophy or repeatable approach. Could be: "I move fast and validate early", "I build for maintainability first", "I align stakeholders before I write a line of code."',
    pullHighlight: false,
    pullPositioning: false,
  },
  {
    templateType: 'valueprop',
    intent: 'Value proposition: synthesis of what this person brings to this specific role. The most direct "hire me for this" slide. Should feel like a closing argument, not a summary.',
    pullHighlight: false,
    pullPositioning: true,
  },
  {
    templateType: 'cta',
    intent: 'CTA: clear next step. Open to opportunities, connect request, or portfolio/email link. Must not be generic — reference the target role or domain.',
    pullHighlight: false,
    pullPositioning: true,
  },
];

// The timeline slide blueprint — inserted after hook when --timeline is used
const TIMELINE_BLUEPRINT: SlideBlueprint = {
  templateType: 'timeline',
  intent: 'Career trajectory: visual timeline of roles (and education if relevant) showing the candidate\'s growth arc. Highlighted nodes mark experience most relevant to this role.',
  pullHighlight: false,
  pullPositioning: false,
};

// Extended structures for 6 or 8 slides (without timeline)
const SIX_SLIDE_STRUCTURE = DEFAULT_SLIDE_STRUCTURE.filter(
  (_, i) => i !== 4 // Remove workstyle slide for 6-slide version
);

const EIGHT_SLIDE_STRUCTURE: SlideBlueprint[] = [
  DEFAULT_SLIDE_STRUCTURE[0], // hook
  DEFAULT_SLIDE_STRUCTURE[1], // fit
  DEFAULT_SLIDE_STRUCTURE[2], // proof 1
  DEFAULT_SLIDE_STRUCTURE[3], // proof 2
  {
    // Extra proof slide for 8-slide version
    templateType: 'proof',
    intent: 'Third proof or domain signal: either a third achievement or a domain-specific credential (open source, publication, leadership program, etc.).',
    pullHighlight: true,
    pullPositioning: false,
  },
  DEFAULT_SLIDE_STRUCTURE[4], // workstyle
  DEFAULT_SLIDE_STRUCTURE[5], // value prop
  DEFAULT_SLIDE_STRUCTURE[6], // cta
];

/**
 * Insert the timeline slide after hook in any structure.
 * The remaining slides keep their order.
 */
function withTimeline(structure: SlideBlueprint[]): SlideBlueprint[] {
  return [structure[0], TIMELINE_BLUEPRINT, ...structure.slice(1)];
}

// ---------------------------------------------------------------------------
// Outline builder
// ---------------------------------------------------------------------------

/**
 * Assign the N-th best highlight to a proof slide.
 * Ensures different slides get different highlights (no reuse).
 */
function assignHighlights(
  outlines: SlideBlueprint[],
  highlights: HighlightCandidate[]
): string[] {
  const highlightRefs: string[] = [];
  let highlightIndex = 0;

  for (const blueprint of outlines) {
    if (blueprint.pullHighlight && highlightIndex < highlights.length) {
      highlightRefs.push(highlights[highlightIndex].text);
      highlightIndex++;
    } else {
      highlightRefs.push('');
    }
  }

  return highlightRefs;
}

/**
 * Build the ordered slide outline array given fit data, ranked highlights, and positioning angle.
 * When showTimeline is true, a timeline slide is inserted after the hook.
 */
export function buildCarouselOutline(
  fit: FitAnalysis,
  highlights: HighlightCandidate[],
  angle: PositioningAngle,
  slideCount: number,
  showTimeline = false
): SlideOutline[] {
  // Select the appropriate base structure
  // For 9-10 slides, use the 8-slide base and add extra proof slides
  let structure: SlideBlueprint[];
  if (slideCount === 6) {
    structure = SIX_SLIDE_STRUCTURE;
  } else if (slideCount === 8) {
    structure = EIGHT_SLIDE_STRUCTURE;
  } else if (slideCount >= 9) {
    // Extra proof slides inserted before workstyle
    const extraProofs: SlideBlueprint[] = Array.from({ length: slideCount - 8 }, (_, k) => ({
      templateType: 'proof' as const,
      intent: `Additional proof slide ${k + 4}: a domain credential, award, or notable project that adds credibility. Contrast with earlier proof slides on skill area and scope.`,
      pullHighlight: true,
      pullPositioning: false,
    }));
    structure = [
      EIGHT_SLIDE_STRUCTURE[0],   // hook
      EIGHT_SLIDE_STRUCTURE[1],   // fit
      EIGHT_SLIDE_STRUCTURE[2],   // proof 1
      EIGHT_SLIDE_STRUCTURE[3],   // proof 2
      EIGHT_SLIDE_STRUCTURE[4],   // proof 3
      ...extraProofs,              // proof 4+ (for 9+ slides)
      EIGHT_SLIDE_STRUCTURE[5],   // workstyle
      EIGHT_SLIDE_STRUCTURE[6],   // value prop
      EIGHT_SLIDE_STRUCTURE[7],   // cta
    ];
  } else {
    structure = DEFAULT_SLIDE_STRUCTURE; // default 7
  }

  // Inject timeline slide after hook if requested
  if (showTimeline) {
    structure = withTimeline(structure);
  }

  const highlightRefs = assignHighlights(structure, highlights);

  return structure.map((blueprint, index) => ({
    slideNumber: index + 1,
    templateType: blueprint.templateType,
    intent: blueprint.intent,
    highlightRef: blueprint.pullHighlight ? highlightRefs[index] : undefined,
    positioningRef: blueprint.pullPositioning ? angle.headline : undefined,
  }));
}