const svg = d3.select("svg"),
      margin = {top: 80, right: 30, bottom: 150, left: 60},
      width = +svg.attr("width") - margin.left - margin.right,
      height = +svg.attr("height") - margin.top - margin.bottom,
      g = svg.append("g").attr("transform", `translate(${margin.left},${margin.top})`);

const x0 = d3.scaleBand().rangeRound([0, width]).paddingInner(0.1);
const x1 = d3.scaleBand().padding(0.05);
const y = d3.scaleLinear().rangeRound([height, 0]);

const educationLevels = [
  "Pre-primary, primary and lower secondary education",
  "Upper secondary and post-secondary non-tertiary, all programmes",
  "Tertiary education"
];

const color = d3.scaleOrdinal()
  .domain(educationLevels)
  .range(["#4E79A7", "#F28E2B", "#59A14F"]);

const tooltip = d3.select("body").append("div").attr("class", "tooltip");

const chartTitle1 = svg.append("text")
  .attr("x", +svg.attr("width") / 2)
  .attr("y", 30)
  .attr("text-anchor", "middle")
  .style("font-size", "20px")
  .style("font-weight", "bold");

const chartTitle2 = svg.append("text")
  .attr("x", +svg.attr("width") / 2)
  .attr("y", 55)
  .attr("text-anchor", "middle")
  .style("font-size", "18px")
  .style("fill", "#666");

const noDataText = g.append("text")
  .attr("x", width / 2)
  .attr("y", height / 2)
  .attr("text-anchor", "middle")
  .style("font-size", "18px")
  .style("fill", "#999")
  .style("display", "none")
  .text("No data available for selected filters");

// Dark mode toggle
const darkModeToggle = document.createElement('button');
darkModeToggle.textContent = 'Toggle Dark Mode';
Object.assign(darkModeToggle.style, {
  margin: '5px',
  padding: '8px 12px',
  fontSize: '14px',
  cursor: 'pointer',
  border: 'none',
  borderRadius: '4px',
  backgroundColor: '#333',
  color: '#fff'
});
document.querySelector('.controls').appendChild(darkModeToggle);

let darkMode = false;
darkModeToggle.addEventListener('click', () => {
  darkMode = !darkMode;
  document.body.style.backgroundColor = darkMode ? '#121212' : '#fff';
  document.body.style.color = darkMode ? '#eee' : '#000';
  darkModeToggle.style.backgroundColor = darkMode ? '#eee' : '#333';
  darkModeToggle.style.color = darkMode ? '#000' : '#fff';
  tooltip.style("background-color", darkMode ? "#222" : "#fff")
         .style("color", darkMode ? "#eee" : "#000");
  g.selectAll("text").style("fill", darkMode ? "#eee" : "#000");
});

d3.csv("PHSwithContinent.csv").then(function(data) {
  const allData = data;

  const continents = Array.from(new Set(data.map(d => d.CONTINENT))).sort();
  continents.forEach(continent => {
    d3.select("#continentSelect")
      .append("option")
      .attr("value", continent)
      .text(continent);
  });

  educationLevels.forEach(level => {
    d3.select("#incomeSelect")
      .append("option")
      .attr("value", level)
      .text(level);
  });

  const legend = d3.select("#legend");
  color.domain().forEach(d => {
    const item = legend.append("div").attr("class", "legend-item");
    item.append("div")
      .attr("class", "legend-color")
      .style("background-color", color(d));
    item.append("span").text(d);
  });

  function updateChart() {
    const selectedContinent = d3.select("#continentSelect").property("value");
    const selectedSex = d3.select("#sexSelect").property("value");
    const selectedEdu = d3.select("#incomeSelect").property("value");

    // Two-line title
    let title1 = "Self-Reported Health";
    let title2 = "";
    if (selectedContinent !== "All") title2 += `${selectedContinent}`;
    if (selectedSex !== "All") title2 += (title2 ? ", " : "") + selectedSex;
    if (selectedEdu !== "All") title2 += (title2 ? ", " : "") + selectedEdu;

    chartTitle1.text(title1);
    chartTitle2.text(title2);

    let filteredData = allData.filter(d =>
      (selectedContinent === "All" || d.CONTINENT === selectedContinent) &&
      (selectedSex === "All" || d.Sex === selectedSex) &&
      (selectedEdu === "All" || d["Socio-economic status"] === selectedEdu)
    );

    filteredData = filteredData.filter(d =>
      educationLevels.includes(d["Socio-economic status"]) &&
      !isNaN(parseFloat(d.OBS_VALUE))
    );

    const countries = Array.from(new Set(filteredData.map(d => d["Reference area"])));
    x0.domain(countries);
    x1.domain(educationLevels).rangeRound([0, x0.bandwidth()]);
    y.domain([0, 100]);

    g.selectAll("*").remove();

    if (filteredData.length === 0) {
      noDataText.style("display", null);
      return;
    } else {
      noDataText.style("display", "none");
    }

    const groupedData = filteredData.reduce((acc, d) => {
      const found = acc.find(v => v.Country === d["Reference area"]);
      const value = parseFloat(d.OBS_VALUE);
      const entry = { ...d, value };
      if (found) found.values.push(entry);
      else acc.push({ Country: d["Reference area"], values: [entry] });
      return acc;
    }, []);

    const countryGroups = g.append("g")
      .selectAll("g")
      .data(groupedData)
      .join("g")
      .attr("transform", d => `translate(${x0(d.Country)},0)`)
      .attr("class", "country-group");

    const bars = countryGroups.selectAll("rect")
      .data(d => d.values)
      .join("rect")
      .attr("x", d => x1(d["Socio-economic status"]))
      .attr("width", x1.bandwidth())
      .attr("fill", d => color(d["Socio-economic status"]))
      .attr("y", height)
      .attr("height", 0)
      .attr("class", "bar")
      .on("mouseover", function(event, d) {
        tooltip.html(`<strong>${d["Reference area"]}</strong><br/>${d["Socio-economic status"]}: ${d.OBS_VALUE}%`)
          .style("left", (event.pageX + 10) + "px")
          .style("top", (event.pageY - 40) + "px")
          .transition().duration(300)
          .style("opacity", 1)
          .style("transform", "translateY(-10px)");
        d3.select(this.parentNode).selectAll("rect").style("opacity", 1);
        g.selectAll(".country-group").filter(gd => gd.Country !== d["Reference area"])
          .selectAll("rect").style("opacity", 0.2);
      })
      .on("mouseout", function() {
        tooltip.transition().duration(500)
          .style("opacity", 0)
          .style("transform", "translateY(0px)");
        g.selectAll("rect").style("opacity", 0.8);
      });

    bars.transition()
      .duration(800)
      .ease(d3.easeCubicOut)
      .attr("y", d => y(d.value))
      .attr("height", d => height - y(d.value));

    g.append("g")
      .attr("transform", `translate(0,${height})`)
      .call(d3.axisBottom(x0))
      .selectAll("text")
      .attr("transform", "rotate(45)")
      .style("text-anchor", "start");

    g.append("g")
      .call(d3.axisLeft(y).ticks(10));

    // Annotate lowest
    if (groupedData.length > 0) {
      const flat = groupedData.flatMap(g => g.values);
      const lowest = flat.reduce((min, d) => d.value < min.value ? d : min, flat[0]);

      const barX = x0(lowest["Reference area"]) + x0.bandwidth() / 2;
      const barY = y(lowest.value);

      g.append("rect")
        .attr("x", barX - 50)
        .attr("y", barY - 30)
        .attr("width", 100)
        .attr("height", 18)
        .attr("rx", 4)
        .attr("fill", darkMode ? "#222" : "#fff")
        .attr("opacity", 0.85);

      g.append("text")
        .attr("x", barX)
        .attr("y", barY - 17)
        .attr("text-anchor", "middle")
        .style("font-size", "12px")
        .style("font-weight", "bold")
        .style("fill", darkMode ? "#fff" : "red")
        .text(`Lowest: ${lowest["Reference area"]}`);
    }
  }

  updateChart();
  d3.select("#loading").classed("hidden", true);

  d3.selectAll("select").on("change", updateChart);

  d3.select("#resetButton").on("click", function() {
    d3.select("#continentSelect").property("value", "All");
    d3.select("#sexSelect").property("value", "All");
    d3.select("#incomeSelect").property("value", "All");
    updateChart();
  });

  d3.select("#downloadButton").on("click", function() {
    const c = d3.select("#continentSelect").property("value");
    const s = d3.select("#sexSelect").property("value");
    const e = d3.select("#incomeSelect").property("value");

    const parts = [
      "education_health",
      c !== "All" ? c : null,
      s !== "All" ? s : null,
      e !== "All" ? e.replace(/[^a-zA-Z0-9]+/g, "_").toLowerCase() : null
    ].filter(Boolean);

    const filename = parts.join("_") + ".png";
    saveSvgAsPng.saveSvgAsPng(document.querySelector("svg"), filename);
  });
});