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 QUALITY RULES (CRITICAL - NON-NEGOTIABLE):
1. USE WHITE FILLS: Every closed shape (head, body, legs, eyes) MUST have fill="#FFFFFF". This hides lines behind it.
2. DRAWING ORDER: Draw from BACK to FRONT. Background parts first (tail, back legs), then main body, then front details (eyes, nose).
3. CLOSED PATHS: All shapes must be fully closed paths so they can be filled with white.
4. NO OVERLAPPING MESS: White fills solve this. If you draw a leg over a body, the white fill of the leg must hide the body line behind it.

🚨 SVG REQUIREMENTS (CRITICAL):
- Background: <rect width="500" height="500" fill="#FFFFFF"/> (Start with white canvas)
- Stroke: stroke="black" or stroke="#000000"
- Stroke Width: stroke-width="2" for main outlines, "2" for details
- Fill: fill="#FFFFFF" for all object parts (to block lines behind)
- Fill: fill="none" ONLY for open paths like whiskers or smiles
- Example Closed Shape: <path d="M..." fill="#FFFFFF" stroke="black" stroke-width="3"/>
- Example Open Line: <path d="M..." fill="none" stroke="black" stroke-width="2"/>

📐 STEP-BY-STEP CONSTRUCTION METHOD (Layer by Layer):

For ANIMALS (Draw in this order):
1. BACK LEGS/TAIL (Furthest back): Draw simple shapes, fill="#FFFFFF", stroke="black"
2. BODY (Middle): Large oval/shape, fill="#FFFFFF", stroke="black" (Hides the top of back legs)
3. HEAD (Front): Large circle/shape, fill="#FFFFFF", stroke="black" (Hides neck/body connection)
4. FRONT LEGS (Front): Shapes overlapping body, fill="#FFFFFF", stroke="black"
5. FACE DETAILS (Topmost): Eyes, nose, mouth. Eyes can have black pupils.

For OBJECTS (Car, Rocket, etc):
1. MAIN CHASSIS/BODY: Large filled shape (fill="#FFFFFF")
2. WHEELS/WINGS: Draw on top or behind as needed
3. WINDOWS/DOORS: Draw on top of body (fill="#FFFFFF")
4. DETAILS: Lines, handles, bolts

For PLANTS:
1. STEM/BRANCHES: Main lines
2. LEAVES BEHIND: Fill="#FFFFFF"
3. FLOWER CENTER: Fill="#FFFFFF" (Draw last so it's on top)
4. PETALS: Fill="#FFFFFF"

🎨 SPECIFIC THEME GUIDES:

UNICORN:
- Body: Oval (fill="#FFFFFF")
- Legs: 4 rectangles (fill="#FFFFFF") - make sure they attach naturally
- Head: Oval/Horse shape (fill="#FFFFFF")
- START with separate shapes, but ensure they LOOK connected
- Horn: Triangle on forehead
- Mane/Tail: Flowing shapes

ROBOT:
- Use geometric shapes (rectangles, circles)
- Fill ALL shapes with #FFFFFF to look solid
- Add buttons/panels on top

🔍 QUALITY CHECKLIST:
✓ Is the main subject clearly visible?
✓ Are lines hidden where shapes overlap? (e.g. body line not visible through arm)
✓ Is everything filled with white (except open lines)?
✓ Is the stroke width consistent (bold 3px)?
✓ Is the image centered in 500x500?

❌ AVOID:
- fill="none" on main shapes (causes messy overlaps)
- Translucent/opacity effects
- Tiny dust/specks
- Disconnected lines that should be closed

${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);
}