{% extends "base.html" %}
{% block title %}TasteEngine — Evaluation{% endblock %}

{% block head_extra %}
  <script src="https://cdn.jsdelivr.net/npm/chart.js@4.4.7/dist/chart.umd.min.js"></script>
{% endblock %}

{% block breadcrumb %}
<ul class="breadcrumb">
  <li><a href="/">Home</a><span class="sep">/</span></li>
  <li class="current">Evaluate</li>
</ul>
{% endblock %}

{% block content %}
{% from "macros.html" import glass, spinner %}

<div x-data="evalApp()">
  {% call glass("Evaluation & Comparison Dashboard") %}
    <p class="text-muted" style="font-size: 0.9rem;">
      Comprehensive analysis of all recommendation methods and approaches using 6 evaluation metrics.
      Methods are evaluated one at a time — results appear as they complete.
    </p>
    <div class="mt-2">
      <button class="btn btn-primary" @click="runEvaluation()" :disabled="running">
        <span x-show="!running">Run Evaluation</span>
        <span x-show="running">Running...</span>
      </button>
    </div>

    <div x-show="running" x-cloak x-transition class="mt-2">
      <div class="flex-between gap-sm" style="margin-bottom:0.5rem;">
        <span class="text-muted" style="font-size:0.85rem;">
          <span x-text="progressText"></span>
          <span x-show="subProgress.total > 0" class="text-dim" style="font-size:0.75rem;">
            — <span x-text="subProgress.current + '/' + subProgress.total"></span>
          </span>
        </span>
        <span class="text-dim" style="font-size:0.8rem;" x-text="progress.current + '/' + progress.total"></span>
      </div>
      <div style="height:4px;background:rgba(255,255,255,0.08);border-radius:2px;overflow:hidden;">
        <div style="height:100%;border-radius:2px;background:linear-gradient(90deg,var(--primary),var(--secondary));transition:width 0.4s ease;" :style="{ width: progressPct + '%' }"></div>
      </div>
      <div x-show="subProgress.total > 0" class="mt-1" style="height:3px;background:rgba(255,255,255,0.04);border-radius:2px;overflow:hidden;">
        <div style="height:100%;border-radius:2px;background:var(--primary);transition:width 0.2s ease;" :style="{ width: subPct + '%' }"></div>
      </div>
    </div>
  {% endcall %}

  <div x-show="hasResults || running" x-cloak x-transition.duration.400ms>

    <div class="kpi-grid" x-show="hasResults" x-cloak>
      <div class="kpi-card kpi-primary">
        <div class="kpi-label">Best RMSE</div>
        <div class="kpi-value"><span x-text="animatedKpis.bestRmse"></span></div>
        <div class="kpi-unit" x-text="'via ' + methodLabel(bestCfMethod)"></div>
      </div>
      <div class="kpi-card kpi-success">
        <div class="kpi-label">Best Method</div>
        <div class="kpi-value" style="font-size:1rem;" x-text="methodLabel(bestCfMethod)"></div>
        <div class="kpi-unit">Lowest RMSE</div>
      </div>
      <div class="kpi-card kpi-secondary">
        <div class="kpi-label">Coverage</div>
        <div class="kpi-value"><span x-text="animatedKpis.coverage"></span></div>
        <div class="kpi-unit" x-text="'by ' + methodLabel(bestCfMethod)"></div>
      </div>
      <div class="kpi-card kpi-warning">
        <div class="kpi-label">Best Precision@5</div>
        <div class="kpi-value"><span x-text="animatedKpis.bestPrecision"></span></div>
        <div class="kpi-unit" x-text="bestApproach ? bestApproach : '—'"></div>
      </div>
    </div>

    {% call glass("Collaborative Filtering — Method Comparison") %}
      <div class="flex-between mb-2">
        <span class="text-dim" style="font-size:0.8rem;" x-show="hasResults">
          Rows appear as each method finishes
        </span>
        <button class="btn btn-ghost btn-sm" @click="exportCSV()" x-show="hasResults">Export CSV</button>
      </div>
      <div style="overflow-x: auto;">
        <table class="eval-table">
          <thead>
            <tr>
              <th>Method</th>
              <th>RMSE ↓</th>
              <th>MAE ↓</th>
              <th>Precision@5 ↑</th>
              <th>Recall@5 ↑</th>
              <th>F1@5 ↑</th>
              <th>Coverage ↑</th>
            </tr>
          </thead>
          <tbody>
            <template x-for="row in cfData" :key="row.method">
              <tr :class="{ 'best-row': row.method === bestCfMethod }" x-cloak x-transition>
                <td>
                  <strong x-text="methodLabel(row.method)"></strong>
                  <span x-show="row.method === bestCfMethod" class="badge-best">BEST</span>
                </td>
                <td x-text="row.RMSE?.toFixed(4)"></td>
                <td x-text="row.MAE?.toFixed(4)"></td>
                <td x-text="row['Precision@5']?.toFixed(4)"></td>
                <td x-text="row['Recall@5']?.toFixed(4)"></td>
                <td x-text="row['F1@5']?.toFixed(4)"></td>
                <td x-text="row.Coverage?.toFixed(4)"></td>
              </tr>
            </template>
            <template x-if="cfData.length === 0 && !running">
              <tr><td colspan="7" class="text-center text-dim" style="padding:2rem;">Click "Run Evaluation" to start</td></tr>
            </template>
          </tbody>
        </table>
      </div>

      <div class="mt-2" x-show="bestCfMethod" x-cloak>
        <span class="badge-best">Best CF Method: <span x-text="methodLabel(bestCfMethod)"></span></span>
      </div>

      <div class="mt-2 chart-container" x-show="chartReady" x-cloak>
        <canvas id="cfChart"></canvas>
      </div>
    {% endcall %}

    <div x-show="approachesLoaded" x-cloak x-transition>
      {% call glass("Approach Comparison (CF vs Content-Based vs Knowledge-Based)") %}
        <div style="overflow-x: auto;">
          <table class="eval-table">
            <thead>
              <tr>
                <th>Approach</th>
                <th>Precision@5 ↑</th>
                <th>Recall@5 ↑</th>
              </tr>
            </thead>
            <tbody>
              <template x-for="row in approachData" :key="row.approach">
                <tr :class="{ 'best-row': row.approach === bestApproach }">
                  <td>
                    <strong x-text="row.approach"></strong>
                    <span x-show="row.approach === bestApproach" class="badge-best">BEST</span>
                  </td>
                  <td x-text="row['Precision@5']?.toFixed(4) || 'N/A'"></td>
                  <td x-text="row['Recall@5']?.toFixed(4) || 'N/A'"></td>
                </tr>
              </template>
            </tbody>
          </table>
        </div>
        <div class="mt-2 chart-container">
          <canvas id="approachChart"></canvas>
        </div>
      {% endcall %}

      {% call glass("Multi-Method Radar Comparison") %}
        <p class="text-muted" style="font-size: 0.85rem; margin-bottom: 1rem;">
          Normalized comparison across all metrics for every CF method.
        </p>
        <div class="chart-container">
          <canvas id="radarChart"></canvas>
        </div>
      {% endcall %}

      {% call glass("Analysis & Insights") %}
        <div class="analysis-block">
          <h4>Which method performs best?</h4>
          <p x-html="analysis.bestMethod"></p>
        </div>
        <div class="analysis-block mt-2">
          <h4>Which approach performs best?</h4>
          <p x-html="analysis.bestApproach"></p>
        </div>
        <div class="analysis-block mt-2">
          <h4>Under what conditions does each perform better?</h4>
          <ul>
            <li><strong>Dense user data:</strong> Collaborative Filtering (leverages peer patterns)</li>
            <li><strong>Cold-start user:</strong> Knowledge-Based (no history needed)</li>
            <li><strong>Cold-start item:</strong> Content-Based (matches item features)</li>
            <li><strong>Explicit constraints:</strong> Knowledge-Based (precise filtering)</li>
            <li><strong>Niche categories:</strong> Content-Based (item features override sparsity)</li>
          </ul>
        </div>
        <div class="analysis-block mt-2">
          <h4>Why do differences occur?</h4>
          <p>Differences arise from algorithmic biases: CF relies on the collective behavior of users, making it powerful for popular items but weak for new users/items. Content-Based depends on feature representation quality and tends to overspecialize. Knowledge-Based is deterministic and transparent but requires explicit user input and domain rules. The choice depends on data availability, user context, and the specific recommendation goal.</p>
        </div>
      {% endcall %}
    </div>

  </div>
</div>
{% endblock %}

{% block scripts %}
<script>
  const methodLabels = {
    user_based: 'User-Based',
    item_based: 'Item-Based',
    svd: 'SVD',
    knn: 'KNN',
    slope_one: 'Slope One'
  };
  const cfMethodNames = ['user_based', 'item_based', 'svd', 'knn', 'slope_one'];

  document.addEventListener('alpine:init', () => {
    Alpine.data('evalApp', () => ({
      running: false,
      hasResults: false,
      cfData: [],
      approachData: [],
      bestCfMethod: null,
      bestApproach: null,
      cfChartInstance: null,
      approachChartInstance: null,
      radarChartInstance: null,
      chartReady: false,
      approachesLoaded: false,
      analysis: {
        bestMethod: 'Run evaluation to find out.',
        bestApproach: 'Run evaluation to find out.'
      },
      animatedKpis: { bestRmse: '—', coverage: '—', bestPrecision: '—' },
      progress: { current: 0, total: 5, label: '' },
      subProgress: { current: 0, total: 0 },

      get progressText() {
        if (!this.running) return '';
        const labels = { user_based: 'User-Based', item_based: 'Item-Based', svd: 'SVD', knn: 'KNN', slope_one: 'Slope One' };
        if (this.progress.current < cfMethodNames.length) {
          const name = cfMethodNames[this.progress.current];
          return `Evaluating ${labels[name] || name}...`;
        }
        if (this.progress.current === cfMethodNames.length) return 'Comparing approaches...';
        return 'Done';
      },

      get progressPct() {
        if (this.progress.total === 0) return 0;
        return (this.progress.current / this.progress.total) * 100;
      },

      get subPct() {
        if (this.subProgress.total === 0) return 0;
        return (this.subProgress.current / this.subProgress.total) * 100;
      },

      methodLabel(id) {
        return methodLabels[id] || id;
      },

      async evaluateMethod(method) {
        const streamMethods = ['svd', 'slope_one'];

        if (streamMethods.includes(method)) {
          return await this.evaluateWithStream(method);
        }

        const controller = new AbortController();
        const timeoutId = setTimeout(() => controller.abort(), 35000);

        try {
          const r = await fetch(`/api/evaluate/cf/${method}`, { signal: controller.signal });
          clearTimeout(timeoutId);
          const data = await r.json();
          if (!data.error) {
            return data;
          } else {
            toast(`${methodLabels[method] || method}: ${data.error}`, 'error');
            return null;
          }
        } catch (err) {
          clearTimeout(timeoutId);
          if (err.name === 'AbortError') {
            toast(`${methodLabels[method] || method} timed out (35s limit), skipping`, 'warning');
          } else {
            toast(`Error evaluating ${methodLabels[method] || method}: ${err.message}`, 'error');
          }
          return null;
        }
      },

      async evaluateWithStream(method) {
        const label = method === 'svd' ? 'epoch' : 'item';
        this.subProgress = { current: 0, total: 0 };

        try {
          const r = await fetch(`/api/evaluate/cf/${method}/stream`);
          const reader = r.body.getReader();
          const decoder = new TextDecoder();
          let buffer = '';

          while (true) {
            const { done, value } = await reader.read();
            if (done) break;

            buffer += decoder.decode(value, { stream: true });
            const lines = buffer.split('\n');
            buffer = lines.pop() || '';

            for (const line of lines) {
              if (!line.trim()) continue;
              try {
                const msg = JSON.parse(line);

                if (msg.type === 'progress') {
                  this.subProgress = { current: msg.current, total: msg.total };
                } else if (msg.type === 'phase') {
                  this.subProgress = { current: 0, total: 0 };
                } else if (msg.type === 'result') {
                  return msg.data;
                } else if (msg.type === 'error') {
                  toast(`${methodLabels[method] || method}: ${msg.message}`, 'error');
                  return null;
                }
              } catch (e) {
                // skip malformed lines
              }
            }
          }
          return null;
        } catch (err) {
          toast(`Error evaluating ${methodLabels[method] || method}: ${err.message}`, 'error');
          return null;
        }
      },

      async runEvaluation() {
        this.running = true;
        this.hasResults = true;
        this.cfData = [];
        this.bestCfMethod = null;
        this.chartReady = false;
        this.approachesLoaded = false;
        this.progress = { current: 0, total: cfMethodNames.length + 1, label: '' };
        this.subProgress = { current: 0, total: 0 };

        for (let i = 0; i < cfMethodNames.length; i++) {
          const method = cfMethodNames[i];
          this.progress.current = i;
          this.progress.label = method;

          if (method === 'svd' || method === 'slope_one') {
            this.subProgress = { current: 0, total: 0 };
          }

          const result = await this.evaluateMethod(method);
          if (result) {
            this.cfData.push(result);
            if (!this.bestCfMethod || result.RMSE < this.getBestRmse()) {
              this.bestCfMethod = result.method;
            }
          }
        }

        this.subProgress = { current: 0, total: 0 };
        this.progress.current = cfMethodNames.length;
        this.progress.label = 'approaches';

        await this.$nextTick();
        this.renderCfChart();

        const best = this.cfData.find(r => r.method === this.bestCfMethod);
        if (best) {
          this.animatedKpis.bestRmse = '0.0000';
          this.animateCounter(this.animatedKpis, 'bestRmse', best.RMSE, 4, 800);
          this.animatedKpis.coverage = '0.0000';
          this.animateCounter(this.animatedKpis, 'coverage', best.Coverage, 4, 800);
        }

        try {
          const r = await fetch('/api/evaluate/approaches');
          const data = await r.json();
          if (!data.error) {
            this.approachData = data.approaches || [];
            this.bestApproach = data.best_approach;
            this.approachesLoaded = true;
            this.analysis.bestMethod = this.buildBestMethodAnalysis();
            this.analysis.bestApproach = this.buildBestApproachAnalysis(data);

            await this.$nextTick();
            this.renderApproachChart(data);
            this.renderRadarChart(data);

            const bestApp = data.approaches?.find(a => a.approach === data.best_approach);
            if (bestApp) {
              this.animatedKpis.bestPrecision = '0.0000';
              this.animateCounter(this.animatedKpis, 'bestPrecision', bestApp['Precision@5'] || 0, 4, 800);
            }
            toast('Evaluation complete', 'success');
          }
        } catch (err) {
          toast('Approach comparison error: ' + err.message, 'error');
        }

        this.running = false;
        this.chartReady = true;
      },

      getBestRmse() {
        const best = this.cfData.find(r => r.method === this.bestCfMethod);
        return best ? best.RMSE : Infinity;
      },

      buildBestMethodAnalysis() {
        const best = this.cfData.find(r => r.method === this.bestCfMethod);
        if (!best) return 'Run evaluation to find out.';

        const methodExplanations = {
          user_based: 'simplicity and direct peer comparison — works well when the target user has enough similar neighbors.',
          item_based: 'direct item-item similarity — effective on dense data where co-rated item pairs are plentiful.',
          svd: 'latent factor modeling — captures hidden patterns in the user-item matrix, excelling on sparse, large-scale data.',
          knn: 'nearest-neighbor aggregation — robust to noise, but performance depends on the quality of the neighbor set.',
          slope_one: 'simplicity and speed of prediction — performs well when rating deviations are consistent across users.',
        };
        const why = methodExplanations[this.bestCfMethod] || 'strong performance on this dataset.';

        return `<strong>${methodLabels[this.bestCfMethod] || this.bestCfMethod}</strong> achieves the lowest RMSE (${best.RMSE.toFixed(4)}) among all CF methods. ` +
               `${methodLabels[this.bestCfMethod] || this.bestCfMethod} excels because of ${why}`;
      },

      buildBestApproachAnalysis(data) {
        if (!data.best_approach) return 'Run evaluation to find out.';
        const bestApp = data.approaches?.find(a => a.approach === data.best_approach);
        const precVal = bestApp ? bestApp['Precision@5'].toFixed(4) : '—';
        const second = [...(data.approaches || [])].sort((a, b) => (b['Precision@5'] || 0) - (a['Precision@5'] || 0));
        const runnerUp = second.length > 1 ? second[1].approach : null;

        const explanations = {
          'Collaborative Filtering': `strongest when rating data is dense (${this.cfData.length} methods averaged). Works by leveraging peer behavior patterns.`,
          'Content-Based': `best when item features are informative (${data.approaches?.length || 0} approaches compared). Shines for cold-start items and niche categories where collaborative signals are weak.`,
          'Knowledge-Based': `ideal for cold-start users with explicit constraints. Deterministic and transparent, but limited by the quality of hand-crafted rules.`,
        };
        const why = explanations[data.best_approach] || 'strong performance on this dataset.';

        let text = `<strong>${data.best_approach}</strong> achieves the highest Precision@5 (${precVal}) on this dataset. ` +
                   `${data.best_approach} performs ${why}`;
        if (runnerUp) {
          text += ` <strong>${runnerUp}</strong> follows as the runner-up.`;
        }
        return text;
      },

      animateCounter(obj, key, target, decimals = 4, duration = 800) {
        const start = performance.now();
        const step = (now) => {
          const elapsed = now - start;
          const pct = Math.min(elapsed / duration, 1);
          const eased = 1 - Math.pow(1 - pct, 3);
          obj[key] = (target * eased).toFixed(decimals);
          if (pct < 1) requestAnimationFrame(step);
        };
        requestAnimationFrame(step);
      },

      exportCSV() {
        if (!this.cfData.length) { toast('No data to export', 'warning'); return; }
        let csv = 'Method,RMSE,MAE,Precision@5,Recall@5,F1@5,Coverage\n';
        this.cfData.forEach(r => {
          csv += `${methodLabels[r.method] || r.method},${r.RMSE},${r.MAE},${r['Precision@5']},${r['Recall@5']},${r['F1@5']},${r.Coverage}\n`;
        });
        if (this.approachData.length) {
          csv += '\nApproach,Precision@5,Recall@5\n';
          this.approachData.forEach(r => {
            csv += `${r.approach},${r['Precision@5'] || 'N/A'},${r['Recall@5'] || 'N/A'}\n`;
          });
        }
        const blob = new Blob([csv], { type: 'text/csv' });
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url; a.download = 'tasteengine_evaluation.csv';
        a.click(); URL.revokeObjectURL(url);
        toast('CSV exported', 'success');
      },

      renderCfChart() {
        if (this.cfChartInstance) this.cfChartInstance.destroy();
        if (this.cfData.length === 0) return;

        const labels = this.cfData.map(r => methodLabels[r.method] || r.method);
        const ctx = document.getElementById('cfChart').getContext('2d');

        this.cfChartInstance = new Chart(ctx, {
          type: 'bar',
          data: {
            labels: labels,
            datasets: [
              {
                label: 'RMSE (lower is better)',
                data: this.cfData.map(r => r.RMSE),
                backgroundColor: 'rgba(108, 99, 255, 0.6)',
                borderColor: '#6C63FF',
                borderWidth: 1
              },
              {
                label: 'MAE (lower is better)',
                data: this.cfData.map(r => r.MAE),
                backgroundColor: 'rgba(255, 101, 132, 0.6)',
                borderColor: '#FF6584',
                borderWidth: 1
              }
            ]
          },
          options: {
            responsive: true, maintainAspectRatio: false,
            plugins: { legend: { labels: { color: 'rgba(255,255,255,0.7)' } } },
            scales: {
              x: { ticks: { color: 'rgba(255,255,255,0.5)' }, grid: { color: 'rgba(255,255,255,0.05)' } },
              y: { beginAtZero: true, ticks: { color: 'rgba(255,255,255,0.5)' }, grid: { color: 'rgba(255,255,255,0.05)' } }
            }
          }
        });
      },

      renderApproachChart(data) {
        if (this.approachChartInstance) this.approachChartInstance.destroy();
        const approaches = data.approaches || [];
        if (approaches.length === 0) return;

        const ctx = document.getElementById('approachChart').getContext('2d');
        this.approachChartInstance = new Chart(ctx, {
          type: 'bar',
          data: {
            labels: approaches.map(r => r.approach),
            datasets: [
              { label: 'Precision@5', data: approaches.map(r => r['Precision@5'] || 0), backgroundColor: 'rgba(108, 99, 255, 0.6)', borderColor: '#6C63FF', borderWidth: 1 },
              { label: 'Recall@5', data: approaches.map(r => r['Recall@5'] || 0), backgroundColor: 'rgba(255, 101, 132, 0.6)', borderColor: '#FF6584', borderWidth: 1 }
            ]
          },
          options: {
            responsive: true, maintainAspectRatio: false,
            plugins: { legend: { labels: { color: 'rgba(255,255,255,0.7)' } } },
            scales: {
              x: { ticks: { color: 'rgba(255,255,255,0.5)' }, grid: { color: 'rgba(255,255,255,0.05)' } },
              y: { beginAtZero: true, ticks: { color: 'rgba(255,255,255,0.5)' }, grid: { color: 'rgba(255,255,255,0.05)' } }
            }
          }
        });
      },

      renderRadarChart(data) {
        if (this.radarChartInstance) this.radarChartInstance.destroy();
        if (this.cfData.length === 0) return;

        const metrics = ['RMSE', 'MAE', 'Precision@5', 'Recall@5', 'F1@5', 'Coverage'];
        const colors = ['rgba(108, 99, 255, 0.3)', 'rgba(255, 101, 132, 0.3)', 'rgba(34, 197, 94, 0.3)', 'rgba(245, 158, 11, 0.3)', 'rgba(59, 130, 246, 0.3)'];
        const borders = ['#6C63FF', '#FF6584', '#22C55E', '#F59E0B', '#3B82F6'];

        const ctx = document.getElementById('radarChart').getContext('2d');
        this.radarChartInstance = new Chart(ctx, {
          type: 'radar',
          data: {
            labels: metrics,
            datasets: this.cfData.map((m, i) => ({
              label: methodLabels[m.method] || m.method,
              data: metrics.map(metric => {
                const vals = this.cfData.map(x => x[metric] || 0);
                const mn = Math.min(...vals);
                const mx = Math.max(...vals);
                return mx === mn ? 1 : ((m[metric] || 0) - mn) / (mx - mn);
              }),
              backgroundColor: colors[i % colors.length],
              borderColor: borders[i % borders.length],
              borderWidth: 2,
              pointBackgroundColor: borders[i % borders.length]
            }))
          },
          options: {
            responsive: true, maintainAspectRatio: false,
            plugins: { legend: { labels: { color: 'rgba(255,255,255,0.7)' } } },
            scales: {
              r: {
                beginAtZero: true, max: 1,
                ticks: { color: 'rgba(255,255,255,0.4)', backdropColor: 'transparent' },
                grid: { color: 'rgba(255,255,255,0.08)' },
                angleLines: { color: 'rgba(255,255,255,0.08)' },
                pointLabels: { color: 'rgba(255,255,255,0.7)', font: { size: 11 } }
              }
            }
          }
        });
      },
    }));
  });
</script>
{% endblock %}