wondersheets/server/prompts.js

/**
 * Activity-specific prompts for worksheet generation.
 * Each prompt is tailored to produce optimal SVG output for its activity type.
 */

const baseRules = `
MANDATORY STYLE & QUALITY RULES — MUST FOLLOW EXACTLY:
- Depict the theme literally and recognizably using standard, cute children's illustration style (e.g. animals look like real animals with big eyes/smiles; no invented blobs, hybrids, pigtails/bows on wrong things, distorted proportions, extra random parts).
- Every visible element MUST be FULLY CLOSED paths (use Z/z to close <path>, or <circle>/<ellipse>/<polygon>/<rect>). NO open paths, NO <line>, NO <polyline> unless closed, NO stroke-only lines without enclosed fill regions.
- Forbidden forever: blobs, distorted/wrong anatomy, floating disconnected lines/parts, random dots/scribbles/noise/artifacts, self-intersecting paths making uncolorable slivers, cut-off/incomplete shapes, inconsistent stroke widths, tiny details, fill="none" on main objects (except holes), any greyscale/shading.
- Stroke: #000000 solid (no dasharray except for traceable writing). Fill: #ffffff on all colorable regions.
- ViewBox: exactly '0 0 500 500'. MAXIMIZE PAGE USAGE. Use the full 500x500 canvas with MINIMAL margins (10-20px). Make the main subject FILL the available space.
- Attributes: single quotes ' only for all XML.
- SVG: complete valid XML — <svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 500 500'> ... </svg>. Use smooth curves (C, Q, S) for natural shapes.
- High-quality kid style: bold thick outlines, big simple shapes, cute friendly expressions (big round eyes as circles/ovals, smiling curved mouth), balanced proportions (big head for cuteness), no complexity/noise.
`;

const ageRules = (age) => `
AGE-SPECIFIC RULES — STRICT:
${age <= 4 ?
    `- For age ${age}: Ultra-simple (1–2 huge objects max), stroke width 6–10px, very large regions (4–10 total), cartoon-big features, no small details/textures/patterns inside.` :
    `- For age ${age}: Slightly more complex (3–6 elements), stroke 3–5px, allow small closed interior shapes (e.g. spots as tiny circles), but still bold and clear.`
  }
`;

const jsonStructure = (sectionType) => `
Return ONLY valid JSON. No other text, no explanations.
JSON exactly this structure:
{
  "title": "Short fun title",
  "subtitle": "Clear one-sentence kid instruction",
  "sections": [
    {
      "id": "${sectionType}-main",
      "type": "${sectionType}",
      "content_svg": "<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 500 500'>...FULL complete valid SVG code here...</svg>"
    }
  ]
}

CRITICAL: content_svg MUST be a string with single quotes in SVG attributes. Paths smooth and 100% closed.
`;

export const activityPrompts = {
  coloring: (theme, age) => `
You are a professional SVG illustrator creating REALISTIC, RECOGNIZABLE children's coloring pages.

Theme: ${theme}
Age: ${age} years old

🎯 YOUR GOAL: Create a coloring page with ONE clear subject that a 3-year-old can immediately identify as "${theme}".

🚨 ABSOLUTE SVG REQUIREMENTS (CRITICAL - NON-NEGOTIABLE):
- EVERY single path MUST have fill="none"
- EVERY single path MUST have stroke="black" or stroke="#000000"
- Use stroke-width="2" or "3" for all outlines
- NO filled shapes allowed - children need empty white areas to color
- Example: <path d="M 100 100 L 200 100" fill="none" stroke="black" stroke-width="2"/>

📐 STEP-BY-STEP SVG CONSTRUCTION METHOD:

For ANIMALS (cat, dog, panda, unicorn, etc.):
1. HEAD: Draw a large circle or oval for head (100-150px diameter), centered around x=250, y=200
2. EARS: Add 2 rounded ears on top of head (circles, triangles, or ovals)
3. EYES: 2 circles (30-40px diameter) positioned symmetrically
4. NOSE: Small circle or triangle in center below eyes
5. MOUTH: Simple curved line (smile) below nose
6. BODY: Large oval or rounded rectangle below head (150-200px wide, 180-220px tall)
7. LEGS: 4 rounded rectangles or ovals extending down from body
8. TAIL: Curved path on one side
9. DETAILS: Add characteristic features (whiskers, spots, horn, etc.)

For OBJECTS (car, rocket, house, etc.):
1. MAIN BODY: Start with basic shape (rectangle for car/house, elongated triangle for rocket)
2. MAJOR COMPONENTS: Add 2-4 large recognizable parts (wheels, windows, door, roof)
3. DETAILS: Add smaller features that make it identifiable

For PLANTS (flower, tree, etc.):
1. CENTER/TRUNK: Main central element
2. PETALS/LEAVES: 5-8 symmetrical rounded shapes around center
3. STEM: Vertical line or path
4. BASE: Ground line or pot

🎨 SPECIFIC THEME EXAMPLES:

UNICORN: 
- Circle head (cx="250" cy="180", r="70")
- 2 triangle ears
- HORN: Triangle pointing up from forehead (30-40px tall)
- 2 circle eyes
- Small nose circle
- Curved smile
- Oval body below head
- 4 rounded rectangle legs
- Flowing curved tail on right side
- Mane: 3-4 curved strokes on neck

PANDA:
- Large circle head (r="80")
- 2 small circle ears on top
- 2 LARGE circle eye patches (r="25", OUTLINED not filled)
- 2 smaller circle eyes inside patches
- Small circle nose
- Smile below nose
- Large oval body
- 4 thick rounded legs
- Optional: bamboo stick to the side (2 parallel lines)

CAT:
- Circle head (r="60")
- 2 triangle ears pointing up
- 2 circle eyes
- Small triangle nose
- Whiskers (3 lines each side)
- Curved smile
- Oval body
- 4 legs
- Curved S-shaped tail

FLOWER:
- Center circle (r="40")
- 6-8 rounded petal paths around center (use ellipses or bezier curves)
- Straight stem line down from center
- 2 leaf shapes on stem (ellipses at angle)
- Simple ground line

🔍 QUALITY CHECKLIST - YOUR SVG MUST:
✓ Have 8-15 large closed shapes ready for coloring
✓ Be IMMEDIATELY recognizable as "${theme}"
✓ Use ONLY stroke outlines (fill="none" on ALL paths)
✓ Have bold stroke-width="2" or "3"
✓ Be 500x500 viewBox with subject centered
✓ Include characteristic features (horn for unicorn, eye patches for panda, etc.)
✓ Have simple, rounded, child-friendly shapes
✓ Look like it came from a store-bought coloring book

❌ AVOID:
- Abstract or geometric art
- Filled/colored areas
- Tiny details (too hard for kids)
- Complex overlapping shapes
- Unrecognizable forms

${baseRules}
${ageRules(age)}
${jsonStructure('coloring')}
`,

  writing: (theme, age) => `
You are an educational illustrator creating handwriting practice worksheets for young children.

Theme: ${theme}
Age: ${age} years old

YOUR MISSION: Create a clean, professional tracing practice worksheet. 
IMPORTANT: Randomly choose ONE of these options for what to trace:
- Option A (50% chance): A short WORD related to the theme (2-4 letters, e.g., "SUN", "CAT", "STAR")
- Option B (50% chance): NUMBERS 1-5 (for ages 3-4) or 1-9 (for ages 5-7), showing 3-5 numbers to trace

⚠️ STRICT ACTIVITY RESTRICTION — THIS IS A TRACING WORKSHEET ONLY:
- DO NOT include any mazes, paths to follow, or puzzles
- DO NOT include any counting exercises with objects
- DO NOT include large coloring illustrations
- DO NOT include groups of objects to count
- DO NOT include any decorative shapes, swirls, or random elements
- The ONLY activity is tracing letters OR numbers along dotted lines

🔴 CRITICAL ALIGNMENT & QUALITY RULES — MUST FOLLOW EXACTLY:

BASELINE ALIGNMENT:
- ALL characters in a row MUST sit on the SAME horizontal baseline
- Use a consistent y-coordinate for the bottom of all characters in each row
- Characters must NOT float, sink, or be misaligned with each other

CHARACTER CONSTRUCTION (for both letters AND numbers):
- Use simple <path> elements with stroke-dasharray='8,8' for uniform dots
- Character stroke-width: 4px for clean, visible dots
- Character height: exactly 80px tall
- Character spacing: exactly 70px between character centers
- Use ONLY basic straight lines and simple curves — no fancy flourishes

DOT PATTERN RULES:
- stroke-dasharray='8,8' — uniform 8px dots with 8px gaps
- stroke='#000000' stroke-linecap='round' for round dots
- fill='none' — characters are outlines only, not filled
- Dots must be evenly spaced along the entire character path

FORBIDDEN ELEMENTS:
- Random decorative dots or shapes anywhere
- Swirls, flourishes, or artistic embellishments  
- Uneven or inconsistent dot spacing
- Characters of different sizes in the same row
- Floating or disconnected character parts
- Any shapes not part of the traceable characters
- Background decorations or patterns

WORKSHEET STRUCTURE — CRITICAL SPACING:
- Title area (y=30-60): Small title as SOLID black text (NOT dotted), font-size 24px, centered at y=50
  - For words: "Trace: [WORD]"
  - For numbers: "Trace the Numbers"
- LEAVE EMPTY SPACE between y=60 and y=150 — NO content here!
- Row 1 (y=180-260): Full dotted characters to trace — tops at y=160, bottoms at y=260
- Row 2 (y=300-380): Same characters, slightly lighter (stroke='#888888')
- Row 3 (y=420-480): Empty baseline only (solid line at y=450, stroke-width='1', stroke='#CCCCCC')
- Baseline guides: Add thin gray lines under each character row

STYLE FOR NUMBERS (if tracing numbers):
- Simple, clear digit shapes: 1, 2, 3, 4, 5, 6, 7, 8, 9
- Consistent sizing and spacing
- School-style number forms

STYLE FOR LETTERS (if tracing words):
- Use basic school-style uppercase letters
- Simple straight lines and gentle curves
- Maximum 4 letters per word

${baseRules}
${ageRules(age)}
${jsonStructure('writing')}
`,

  'find-way': (theme, age) => `
You are a puzzle designer creating fun maze worksheets for young children.

Theme: ${theme}
Age: ${age} years old

YOUR MISSION: Create a SIMPLE, LOGICAL, and clearly SOLVABLE maze for young children.

⚠️ STRICT ACTIVITY RESTRICTION — THIS IS A MAZE/PATH-FINDING WORKSHEET ONLY:
- DO NOT include any numbers, digits, or counting exercises
- DO NOT include any letters, words, or writing practice
- DO NOT include large coloring areas — the maze IS the main activity
- The ONLY activity is finding the path through the maze from start to finish

🔴 CRITICAL MAZE LOGIC RULES — MUST FOLLOW EXACTLY:
1. USE A SIMPLE GRID STRUCTURE: Build the maze on an invisible 5x5 or 6x6 grid
2. CORRIDORS MUST BE STRAIGHT: Only horizontal and vertical paths, meeting at 90° angles
3. PATH WIDTH: Exactly 40px wide corridors — consistent everywhere
4. WALLS: Solid filled rectangles (not lines), exactly 10px thick, black fill
5. ONE CLEAR SOLUTION: There must be exactly ONE path from start to finish — no alternate routes
6. DEAD ENDS: Maximum 2-3 short dead ends (1-2 cells deep only)
7. NO OVERLAPPING: Paths never cross or overlap — walls completely separate all corridors
8. NO AMBIGUITY: Every junction must have clear wall boundaries — no gaps or unclear areas

MAZE STRUCTURE (follow this pattern):
- Draw a rectangular outer border (10px thick black rectangle)
- Inside, create corridors by placing rectangular wall blocks
- Corridors are the WHITE SPACE between walls
- START: Top-left area with a small themed icon (arrow or character)
- FINISH: Bottom-right area with a themed goal icon (star, treasure, home)
- Solution path should have 4-6 turns maximum

SVG CONSTRUCTION METHOD:
1. Draw outer border: <rect x='10' y='10' width='480' height='480' fill='none' stroke='#000' stroke-width='10'/>
2. Add internal walls as filled black rectangles: <rect x='...' y='...' width='...' height='...' fill='#000'/>
3. Corridors are the remaining white space (no need to draw them)
4. Add START icon at entrance
5. Add FINISH icon at exit

FORBIDDEN IN MAZES:
- Curved or diagonal paths
- Walls that don't connect properly (gaps)
- Paths that seem to go through walls
- Multiple possible solutions
- Dead ends longer than 2 grid cells
- Unclear or ambiguous junctions

${baseRules}
${ageRules(age)}
${jsonStructure('find-the-way')}
`,

  counting: (theme, age) => `
You are an educational illustrator creating counting practice worksheets for young children.

Theme: ${theme}
Age: ${age} years old

YOUR MISSION: Create a fun counting exercise where children count themed objects and write the number.

⚠️ STRICT ACTIVITY RESTRICTION — THIS IS A COUNTING WORKSHEET ONLY:
- DO NOT include any mazes, paths to follow, or puzzles
- DO NOT include any letters, words, or writing/tracing practice (except answer boxes)
- DO NOT include large coloring illustrations — only countable themed objects
- DO NOT show the answers/numbers already filled in — leave answer boxes EMPTY
- DO NOT include number recognition (showing big numbers) — this is COUNTING objects
- The ONLY activity is counting groups of objects and writing the total in empty boxes
- Focus EXCLUSIVELY on groups of themed objects to count with empty answer boxes

COUNTING WORKSHEET SPECIFIC RULES:
- Create 3-5 GROUPS of themed objects to count
- Each group should have a DIFFERENT quantity (e.g., 2, 4, 5, 7, 9)
- Quantities appropriate for age: 1-5 for age 3-4, 1-10 for age 5-7
- Objects within each group must be IDENTICAL and themed
- Add an EMPTY box or circle next to each group for writing the answer (no numbers inside!)
- Objects should be large enough to count easily with a finger point

LAYOUT:
- Use GRID LAYOUT: Groups in rows, empty answer boxes on the right
- Each row: [Group of objects] → [Empty answer box]
- Clear visual separation between different groups

COUNTING-FRIENDLY DESIGN:
- Space objects clearly within groups — no overlapping
- Use familiar arrangements (lines, dice patterns, pyramid stacks)
- Make objects touch-friendly for finger counting
- Vary positions slightly so kids must actually count (not memorize patterns)

${baseRules}
${ageRules(age)}
${jsonStructure('counting')}
`
};

/**
 * Get the appropriate prompt for an activity type
 */
export function getPromptForActivity(activityType, theme, age) {
  // Map internal IDs to prompt keys
  const typeMap = {
    'coloring': 'coloring',
    'writing': 'writing',
    'find-way': 'find-way',
    'find-the-way': 'find-way',
    'counting': 'counting'
  };

  const promptKey = typeMap[activityType] || 'writing';
  const promptGenerator = activityPrompts[promptKey];

  if (!promptGenerator) {
    console.warn(`No prompt found for activity type: ${activityType}, falling back to writing`);
    return activityPrompts.writing(theme, age);
  }

  return promptGenerator(theme, age);
}