/**
 * PDF Export utilities for Iapetus reports.
 * Uses jsPDF for document generation and html2canvas for chart capture.
 */

import { jsPDF } from "jspdf";
import html2canvas from "html2canvas";
import {
  formatCategory,
  formatPackaging,
  formatOxygen,
  formatPreservative,
  formatAcidulant,
  formatRiskClass,
  formatConfidence,
  formatFeature,
  formatDirection,
} from "./formatters";

const APP_VERSION = "0.2.0";

// Color definitions matching the app theme
const COLORS = {
  accent: [38, 70, 83],       // #264653
  accentLight: [51, 101, 138], // #33658a
  riskLow: [42, 157, 143],    // #2a9d8f
  riskModerate: [233, 196, 106], // #e9c46a
  riskHigh: [231, 111, 81],   // #e76f51
  riskCritical: [143, 29, 20], // #8f1d14
  text: [27, 42, 47],         // #1b2a2f
  muted: [88, 101, 107],      // #58656b
  border: [216, 221, 212],    // #d8ddd4
};

function getRiskColor(riskClass) {
  const normalized = String(riskClass).toLowerCase();
  if (normalized === "low") return COLORS.riskLow;
  if (normalized === "moderate") return COLORS.riskModerate;
  if (normalized === "high") return COLORS.riskHigh;
  if (normalized === "critical") return COLORS.riskCritical;
  return COLORS.muted;
}

function generateFilename() {
  const now = new Date();
  const timestamp = now.toISOString().replace(/[:.]/g, "-").slice(0, 19);
  return `iapetus_report_${timestamp}.pdf`;
}

function formatTimestamp() {
  return new Date().toLocaleString("en-GB", {
    year: "numeric",
    month: "long",
    day: "numeric",
    hour: "2-digit",
    minute: "2-digit",
  });
}

/**
 * Generate a PDF report from simulation results.
 * @param {object} result - The simulation result from the API
 * @param {object} scenario - The input scenario parameters
 * @param {HTMLElement} chartElement - The chart DOM element to capture
 */
export async function exportReportAsPDF(result, scenario, chartElement) {
  const doc = new jsPDF({
    orientation: "portrait",
    unit: "mm",
    format: "a4",
  });

  const pageWidth = doc.internal.pageSize.getWidth();
  const pageHeight = doc.internal.pageSize.getHeight();
  const margin = 15;
  const contentWidth = pageWidth - (margin * 2);
  let y = margin;

  // Helper function for adding text
  function addText(text, x, currentY, options = {}) {
    const {
      fontSize = 10,
      fontStyle = "normal",
      color = COLORS.text,
      maxWidth = contentWidth,
    } = options;

    doc.setFontSize(fontSize);
    doc.setFont("helvetica", fontStyle);
    doc.setTextColor(...color);

    const lines = doc.splitTextToSize(text, maxWidth);
    doc.text(lines, x, currentY);
    return currentY + (lines.length * fontSize * 0.4);
  }

  // Helper for section headers
  function addSectionHeader(title, currentY) {
    doc.setFillColor(...COLORS.accent);
    doc.rect(margin, currentY - 4, contentWidth, 8, "F");
    doc.setFontSize(11);
    doc.setFont("helvetica", "bold");
    doc.setTextColor(255, 255, 255);
    doc.text(title, margin + 3, currentY + 1);
    return currentY + 10;
  }

  // Helper for drawing a metric box
  function addMetricBox(label, value, x, currentY, width, color = COLORS.accent) {
    doc.setDrawColor(...COLORS.border);
    doc.setLineWidth(0.3);
    doc.rect(x, currentY, width, 18);

    doc.setFontSize(8);
    doc.setFont("helvetica", "normal");
    doc.setTextColor(...COLORS.muted);
    doc.text(label, x + 3, currentY + 5);

    doc.setFontSize(12);
    doc.setFont("helvetica", "bold");
    doc.setTextColor(...color);
    doc.text(String(value), x + 3, currentY + 13);
  }

  // =====================
  // HEADER
  // =====================
  doc.setFillColor(...COLORS.accent);
  doc.rect(0, 0, pageWidth, 28, "F");

  doc.setFontSize(18);
  doc.setFont("helvetica", "bold");
  doc.setTextColor(255, 255, 255);
  doc.text("IAPETUS", margin, 12);

  doc.setFontSize(11);
  doc.setFont("helvetica", "normal");
  doc.text("Shelf-Life Risk Assessment Report", margin, 19);

  doc.setFontSize(8);
  doc.text(`Generated: ${formatTimestamp()}  |  v${APP_VERSION}`, margin, 25);

  y = 36;

  // =====================
  // EXECUTIVE SUMMARY
  // =====================
  y = addSectionHeader("EXECUTIVE SUMMARY", y);

  const decision = result.decision || {};
  const riskClass = decision.growth_risk_class || "unknown";
  const riskColor = getRiskColor(riskClass);

  // Metric boxes
  const boxWidth = (contentWidth - 6) / 3;
  addMetricBox("Risk Level", formatRiskClass(riskClass), margin, y, boxWidth, riskColor);
  addMetricBox(
    "Threshold Probability",
    `${((decision.threshold_exceedance_probability || 0) * 100).toFixed(1)}%`,
    margin + boxWidth + 3,
    y,
    boxWidth
  );
  addMetricBox(
    "Recommended Shelf Life",
    `${decision.recommended_max_shelf_life_days || "N/A"} days`,
    margin + (boxWidth * 2) + 6,
    y,
    boxWidth
  );

  y += 24;

  // Additional metrics row
  doc.setFontSize(9);
  doc.setFont("helvetica", "normal");
  doc.setTextColor(...COLORS.text);

  const challengeText = decision.challenge_test_recommended ? "Yes" : "No";
  const confidenceText = formatConfidence(decision.confidence_label || "unknown");
  doc.text(`Challenge Test Recommended: ${challengeText}   |   Confidence: ${confidenceText}`, margin, y);

  y += 8;

  // =====================
  // SCENARIO PARAMETERS
  // =====================
  y = addSectionHeader("SCENARIO PARAMETERS", y);

  const params = [
    ["Product Category", formatCategory(scenario.product_category)],
    ["Pathogen", scenario.pathogen || "Listeria monocytogenes"],
    ["Storage Temperature", `${scenario.storage_temperature_c}°C`],
    ["Target Shelf Life", `${scenario.target_shelf_life_days} days`],
    ["pH", scenario.ph],
    ["Water Activity (aw)", scenario.aw],
    ["Salt", `${scenario.salt_percent}%`],
    ["Sugar", `${scenario.sugar_percent}%`],
    ["Fat", `${scenario.fat_percent}%`],
    ["Preservative", scenario.preservative_flag ? formatPreservative(scenario.preservative_type) : "None"],
    ["Acidulant", formatAcidulant(scenario.acidulant_type)],
    ["Packaging", formatPackaging(scenario.packaging_type)],
    ["Oxygen Condition", formatOxygen(scenario.oxygen_condition)],
    ["Initial Inoculum", `${scenario.initial_inoculum_log_cfu_g} log CFU/g`],
  ];

  // Two-column layout for parameters
  const colWidth = contentWidth / 2;
  const rowHeight = 5;
  doc.setFontSize(8);

  params.forEach((param, index) => {
    const col = index % 2;
    const row = Math.floor(index / 2);
    const x = margin + (col * colWidth);
    const rowY = y + (row * rowHeight);

    doc.setFont("helvetica", "normal");
    doc.setTextColor(...COLORS.muted);
    doc.text(`${param[0]}:`, x, rowY);

    doc.setFont("helvetica", "bold");
    doc.setTextColor(...COLORS.text);
    doc.text(String(param[1]), x + 40, rowY);
  });

  y += Math.ceil(params.length / 2) * rowHeight + 6;

  // =====================
  // GROWTH CHART
  // =====================
  if (chartElement) {
    y = addSectionHeader("GROWTH PREDICTION", y);

    try {
      const canvas = await html2canvas(chartElement, {
        scale: 2,
        backgroundColor: "#ffffff",
        logging: false,
      });

      const imgData = canvas.toDataURL("image/png");
      const imgWidth = contentWidth;
      const imgHeight = (canvas.height / canvas.width) * imgWidth;

      // Check if we need a new page
      if (y + imgHeight > pageHeight - margin) {
        doc.addPage();
        y = margin;
        y = addSectionHeader("GROWTH PREDICTION (continued)", y);
      }

      doc.addImage(imgData, "PNG", margin, y, imgWidth, imgHeight);
      y += imgHeight + 6;
    } catch (error) {
      console.error("Failed to capture chart:", error);
      y = addText("Chart capture failed. See web application for visualization.", margin, y);
      y += 6;
    }
  }

  // Check page space for risk drivers
  if (y > pageHeight - 80) {
    doc.addPage();
    y = margin;
  }

  // =====================
  // KEY RISK FACTORS
  // =====================
  const drivers = result.sensitivity_analysis?.drivers || [];
  if (drivers.length > 0) {
    y = addSectionHeader("KEY RISK FACTORS", y);

    // Table header
    doc.setFillColor(245, 245, 245);
    doc.rect(margin, y, contentWidth, 6, "F");
    doc.setFontSize(8);
    doc.setFont("helvetica", "bold");
    doc.setTextColor(...COLORS.text);
    doc.text("Factor", margin + 2, y + 4);
    doc.text("Probability Impact", margin + 55, y + 4);
    doc.text("Growth Change", margin + 95, y + 4);
    doc.text("Shelf-Life Impact", margin + 135, y + 4);

    y += 8;

    // Table rows (top 6 drivers)
    const topDrivers = drivers.slice(0, 6);
    doc.setFontSize(8);
    doc.setFont("helvetica", "normal");

    topDrivers.forEach((driver) => {
      const probImpact = (driver.impact_on_exceedance_probability * 100);
      const logImpact = driver.impact_on_final_log_cfu_g;
      const shelfImpact = driver.impact_on_recommended_shelf_life_days;

      // Factor name with direction
      doc.setTextColor(...COLORS.text);
      doc.text(formatFeature(driver.feature), margin + 2, y);

      // Probability impact (color-coded)
      const probColor = probImpact >= 0 ? COLORS.riskHigh : COLORS.riskLow;
      doc.setTextColor(...probColor);
      doc.text(`${probImpact >= 0 ? "+" : ""}${probImpact.toFixed(1)}%`, margin + 55, y);

      // Growth change (color-coded)
      const logColor = logImpact >= 0 ? COLORS.riskHigh : COLORS.riskLow;
      doc.setTextColor(...logColor);
      doc.text(`${logImpact >= 0 ? "+" : ""}${logImpact.toFixed(2)} log CFU/g`, margin + 95, y);

      // Shelf-life impact (color-coded)
      const shelfColor = shelfImpact <= 0 ? COLORS.riskHigh : COLORS.riskLow;
      doc.setTextColor(...shelfColor);
      doc.text(`${shelfImpact > 0 ? "+" : ""}${shelfImpact} days`, margin + 135, y);

      y += 5;
    });

    y += 4;
  }

  // Check page space for summary
  if (y > pageHeight - 60) {
    doc.addPage();
    y = margin;
  }

  // =====================
  // AI ANALYSIS
  // =====================
  if (result.summary) {
    y = addSectionHeader("AI ANALYSIS", y);

    doc.setFontSize(9);
    doc.setFont("helvetica", "normal");
    doc.setTextColor(...COLORS.text);

    const summaryLines = doc.splitTextToSize(result.summary, contentWidth - 4);
    doc.text(summaryLines, margin + 2, y);
    y += summaryLines.length * 4;

    if (result.summary_provider) {
      doc.setFontSize(7);
      doc.setTextColor(...COLORS.muted);
      doc.text(`Source: ${result.summary_provider}`, margin + 2, y + 2);
      y += 6;
    }
  }

  // =====================
  // DISCLAIMER
  // =====================
  // Ensure disclaimer fits on page
  if (y > pageHeight - 30) {
    doc.addPage();
    y = margin;
  }

  y += 4;
  doc.setDrawColor(...COLORS.border);
  doc.setLineWidth(0.5);
  doc.line(margin, y, margin + contentWidth, y);
  y += 6;

  doc.setFillColor(255, 250, 240);
  doc.rect(margin, y, contentWidth, 20, "F");
  doc.setDrawColor(...COLORS.riskModerate);
  doc.setLineWidth(0.3);
  doc.rect(margin, y, contentWidth, 20, "S");

  doc.setFontSize(7);
  doc.setFont("helvetica", "bold");
  doc.setTextColor(...COLORS.riskHigh);
  doc.text("IMPORTANT DISCLAIMER", margin + 3, y + 4);

  doc.setFont("helvetica", "normal");
  doc.setTextColor(...COLORS.text);
  const disclaimer = "This report is generated by an exploratory simulation tool trained on synthetic data. It is not a regulatory-validated decision-making tool and should not be used as a substitute for formal challenge testing or shelf-life validation. Always consult with qualified food safety professionals.";
  const disclaimerLines = doc.splitTextToSize(disclaimer, contentWidth - 6);
  doc.text(disclaimerLines, margin + 3, y + 9);

  // Save the PDF
  doc.save(generateFilename());
}

/**
 * Export the simulation report as PDF (main entry point).
 * @param {object} result - The simulation result from the API
 * @param {object} scenario - The input scenario parameters
 * @param {HTMLElement} chartElement - The chart DOM element to capture
 */
export async function exportReport(result, scenario, chartElement) {
  await exportReportAsPDF(result, scenario, chartElement);
}