feat: Add decoding and scoring for vertical visibility (VV)

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

metar.html

@@ -63,19 +63,19 @@
         <label style="margin-left: 1em;"><input type="checkbox" id="decode-all-checkbox"> Decode all</label>
         <div id="decoding-display"></div>
         <button id="next-btn" style="margin-top: 1em;">Next</button>
-        <button id="test-all-btn">Test All METARs</button>
     </div>
     <script>
         const metarDisplay = document.getElementById('metar-display');
         const decodingDisplay = document.getElementById('decoding-display');
         const newMetarBtn = document.getElementById('new-metar-btn');
-        const testAllBtn = document.getElementById('test-all-btn');
         const nextBtn = document.getElementById('next-btn');
         const decodeAllCheckbox = document.getElementById('decode-all-checkbox');
         const metars = [];
+        let sortedMetars = [];
 
         let currentMetarSections = [];
         let currentSectionIndex = 0;
+        let currentMetarIndex = -1;
 
         // --- METAR Ranking ---
 
@@ -147,9 +147,10 @@
                 }
                 
                 // Clouds
-                if (part.match(/^(BKN|OVC)/)) {
+                if (part.match(/^(BKN|OVC|VV)/)) {
                     score += 1;
-                    const ceilingAlt = parseInt(part.substring(3, 6));
+                    const altCode = part.startsWith('VV') ? part.substring(2, 5) : part.substring(3, 6);
+                    const ceilingAlt = parseInt(altCode);
                     if (!isNaN(ceilingAlt)) {
                         const ceilingFt = ceilingAlt * 100;
                         if (ceilingFt < 500) score += 8;
@@ -285,6 +286,14 @@
         }
 
         function decodeClouds(code, metarString) {
+            if (code.startsWith('VV')) {
+                const height = code.substring(2, 5);
+                if (height === '///') {
+                    return `${code}: Vertical visibility sensor inoperative`;
+                }
+                const alt = parseInt(height) * 100;
+                return `${code}: Vertical visibility ${alt.toLocaleString()} feet`;
+            }
             const coverMap = {
                 'SKC': 'Sky clear',
                 'CLR': 'Sky clear',
@@ -737,22 +746,31 @@
             // Section 1: Airport, Time, Auto
             let airportTimeAutoRaw = [];
             let airportTimeAutoDecoded = [];
+            let preambleEnded = false;
 
-            if (parts[index] && parts[index].length === 4 && parts[index].match(/^[A-Z][A-Z0-9]{3}$/)) {
-                airportTimeAutoRaw.push(parts[index]);
-                airportTimeAutoDecoded.push(decodeAirport(parts[index], metarString));
-                index++;
-            }
-            if (parts[index] && parts[index].endsWith('Z')) {
-                airportTimeAutoRaw.push(parts[index]);
-                airportTimeAutoDecoded.push(decodeTime(parts[index]));
-                index++;
-            }
-            if (parts[index] && parts[index] === 'AUTO') {
-                airportTimeAutoRaw.push(parts[index]);
-                airportTimeAutoDecoded.push("AUTO: Fully automated observation");
-                index++;
+            while(index < parts.length && !preambleEnded) {
+                const part = parts[index];
+                if (part === 'AUTO') {
+                    airportTimeAutoRaw.push(part);
+                    airportTimeAutoDecoded.push("AUTO: Fully automated observation");
+                    index++;
+                } else if (part.length === 4 && part.match(/^[A-Z][A-Z0-9]{3}$/)) {
+                    airportTimeAutoRaw.push(part);
+                    airportTimeAutoDecoded.push(decodeAirport(part, metarString));
+                    index++;
+                } else if (part.endsWith('Z')) {
+                    airportTimeAutoRaw.push(part);
+                    airportTimeAutoDecoded.push(decodeTime(part));
+                    index++;
+                } else if (part.match(/^CC[A-Z]$/)) {
+                    airportTimeAutoRaw.push(part);
+                    airportTimeAutoDecoded.push(`${part}: Correction to the report`);
+                    index++;
+                } else {
+                    preambleEnded = true;
+                }
             }
+
             if (airportTimeAutoRaw.length > 0) {
                 sections.push({
                     raw: airportTimeAutoRaw.join(' '),
@@ -782,7 +800,7 @@
                     sections.push({ raw: part, decoded: decodeVisibility(part) });
                 } else if (part.match(/^([+-]|VC)?(MI|PR|BC|DR|BL|SH|TS|FZ|DZ|RA|SN|SG|IC|PL|GR|GS|UP|BR|FG|FU|VA|DU|SA|HZ|PY|PO|SQ|FC|SS|DS|TR)+$/)) {
                     sections.push({ raw: part, decoded: decodeWeather(part, metarString) });
-                } else if (part.match(/^(SKC|CLR|FEW|SCT|BKN|OVC)/)) {
+                } else if (part.match(/^(VV|SKC|CLR|FEW|SCT|BKN|OVC)/)) {
                     sections.push({ raw: part, decoded: decodeClouds(part, metarString) });
                 } else if (part.match(/^(M?\d{2})\/(M?\d{2})$/)) {
                     sections.push({ raw: part, decoded: decodeTempDew(part) });
@@ -808,25 +826,35 @@
             return sections;
         }
 
-        function displayMetar(index) {
+        function displayMetar(id) {
             if (metars.length === 0) {
                 metarDisplay.textContent = 'No METARs loaded.';
                 return;
             }
 
             let metarIndex;
-            if (index !== undefined && index >= 0 && index < metars.length) {
-                metarIndex = index;
-            } else {
-                // Bias random selection towards the more interesting (higher-scored) METARs at the start of the array.
-                // Math.random() * Math.random() skews distribution towards 0.
-                metarIndex = Math.floor(Math.random() * Math.random() * metars.length);
+
+            // If an ID is provided, try to find it.
+            if (id !== undefined) {
+                metarIndex = metars.findIndex(m => m.line === id);
             }
 
-            const metarString = metars[metarIndex].metar;
-            history.replaceState(null, '', '#' + metarIndex);
+            // If no ID was provided, or the ID was not found, pick a random METAR.
+            if (id === undefined || metarIndex === -1) {
+                const randomSortedIndex = Math.floor(Math.random() * Math.random() * sortedMetars.length);
+                const selectedMetar = sortedMetars[randomSortedIndex];
+                metarIndex = metars.findIndex(m => m.metar === selectedMetar.metar);
+            }
 
-            currentMetarSections = generateMetarSections(metarString);
+            if (metarIndex === currentMetarIndex) {
+                return; // Already displaying this METAR
+            }
+            currentMetarIndex = metarIndex;
+
+            const metarData = metars[metarIndex];
+            history.replaceState(null, '', '#' + metarData.line);
+
+            currentMetarSections = generateMetarSections(metarData.metar);
             currentSectionIndex = 0;
             updateDisplay();
         }
@@ -836,11 +864,11 @@
             .then(data => {
                 const lines = data.split('\n');
                 const rawMetars = [];
-                lines.forEach(line => {
+                lines.forEach((line, index) => {
                     if (line.includes('METAR')) {
                         const metarString = line.substring(line.indexOf('METAR') + 6).replace('=', '').trim();
                         if (metarString) {
-                            rawMetars.push(metarString);
+                            rawMetars.push({ metar: metarString, line: index + 1 });
                         }
                     }
                 });
@@ -849,33 +877,34 @@
                 
                 // 1. Calculate component frequencies for rarity scoring
                 const componentFrequencies = {};
-                rawMetars.forEach(metarString => {
-                    const parts = getMetarParts(metarString);
+                rawMetars.forEach(metarObj => {
+                    const parts = getMetarParts(metarObj.metar);
                     parts.forEach(part => {
                         componentFrequencies[part] = (componentFrequencies[part] || 0) + 1;
                     });
                 });
 
                 // 2. Score and store each METAR
-                rawMetars.forEach(metarString => {
-                    const score = calculateMetarScore(metarString, componentFrequencies, rawMetars.length);
-                    metars.push({ metar: metarString, score: score });
+                rawMetars.forEach(metarObj => {
+                    const score = calculateMetarScore(metarObj.metar, componentFrequencies, rawMetars.length);
+                    metars.push({ metar: metarObj.metar, score: score, line: metarObj.line });
                 });
 
-                // 3. Sort by score descending
-                metars.sort((a, b) => b.score - a.score);
+                // 3. Create a sorted copy for biased random selection, but don't sort the main array
+                sortedMetars = [...metars];
+                sortedMetars.sort((a, b) => b.score - a.score);
 
                 console.log(`Loaded and ranked ${metars.length} METARs.`);
                 console.log(`Top 5 most interesting METARs:`);
-                for (let i = 0; i < Math.min(5, metars.length); i++) {
-                    console.log(`  - Score: ${metars[i].score.toFixed(2)}, METAR: ${metars[i].metar}`);
+                for (let i = 0; i < Math.min(5, sortedMetars.length); i++) {
+                    console.log(`  - Score: ${sortedMetars[i].score.toFixed(2)}, METAR: ${sortedMetars[i].metar}`);
                 }
 
                 const hash = window.location.hash.substring(1);
-                const initialIndex = parseInt(hash, 10);
+                const initialId = parseInt(hash, 10);
 
-                if (!isNaN(initialIndex) && initialIndex >= 0 && initialIndex < metars.length) {
-                    displayMetar(initialIndex);
+                if (!isNaN(initialId)) {
+                    displayMetar(initialId);
                 } else {
                     displayMetar(); // Display initial random METAR
                 }
@@ -887,6 +916,13 @@
 
         newMetarBtn.addEventListener('click', () => displayMetar());
         decodeAllCheckbox.addEventListener('change', updateDisplay);
+        window.addEventListener('hashchange', () => {
+            const hash = window.location.hash.substring(1);
+            const id = parseInt(hash, 10);
+            if (!isNaN(id)) {
+                displayMetar(id);
+            }
+        });
 
         function updateDisplay() {
             if (currentMetarSections.length === 0) return;
@@ -924,7 +960,7 @@
             }
         });
 
-        function testAllMetars() {
+        window.testAllMetars = function() {
             console.log(`--- Starting test of ${metars.length} METARs ---`);
             let failed = 0;
             let withUnknowns = 0;
@@ -937,22 +973,22 @@
                 otherRemarks: new Set(),
             };
 
-            metars.forEach(metarString => {
+            metars.forEach(metarData => {
                 const tempLogs = [];
                 console.log = (...args) => {
                     tempLogs.push(args.join(' '));
                 };
 
                 try {
-                    const sections = generateMetarSections(metarString);
-                    if (sections.length === 0 && metarString.length > 0) {
+                    const sections = generateMetarSections(metarData.metar);
+                    if (sections.length === 0 && metarData.metar.length > 0) {
                         throw new Error("Parser produced no sections");
                     }
                     
                     const hasUnknowns = tempLogs.some(msg => msg.includes('Unknown') || msg.includes('Other remark'));
                     if (hasUnknowns) {
                         withUnknowns++;
-                        originalConsoleLog(`METAR with decoding issues: ${metarString}`);
+                        originalConsoleLog(`METAR with decoding issues: ${metarData.metar}`);
                         tempLogs.forEach(msg => {
                             originalConsoleLog(`  -> ${msg}`);
                             if (msg.startsWith('Unknown Airport code:')) {
@@ -975,7 +1011,7 @@
                     }
 
                 } catch (e) {
-                    console.error("Failed to parse:", metarString, e);
+                    console.error("Failed to parse:", metarData, e);
                     failed++;
                 }
             });
@@ -998,8 +1034,6 @@
                 }
             }
         }
-
-        testAllBtn.addEventListener('click', testAllMetars);
     </script>
 </body>
 </html>