// SummerCMS docs: client-side search over search-index.json.
// The index is fetched lazily on the first open and cached. Result rows are
// built with createElement and textContent only; indexed text is never
// parsed as HTML.
(function () {
  "use strict";

  var MAX_RESULTS = 20;
  var QUERY_KEY = "summer-docs-query";
  var dialog = document.getElementById("search");
  var input = document.getElementById("search-input");
  var list = document.getElementById("search-results");
  var status = document.getElementById("search-status");
  var live = document.getElementById("search-live");
  var trigger = document.querySelector(".search-trigger");
  if (!dialog || !input || !list || !status || typeof dialog.showModal !== "function") {
    return;
  }

  var items = null; // null until loaded
  var loading = null; // the pending load promise
  var loadError = ""; // "server" or "index" after a failed load
  var results = [];
  var activeIndex = -1;

  var isMac = /mac/i.test((navigator.userAgentData && navigator.userAgentData.platform) || navigator.platform || "");
  var kbd = trigger && trigger.querySelector("kbd");
  if (kbd && isMac) {
    kbd.textContent = "⌘ K";
  }

  try {
    input.value = window.sessionStorage.getItem(QUERY_KEY) || "";
  } catch (e) {
    // No session storage: start empty.
  }

  function el(tag, className, text) {
    var node = document.createElement(tag);
    if (className) {
      node.className = className;
    }
    if (text !== undefined) {
      node.textContent = text;
    }
    return node;
  }

  // appendRich appends text in which `code spans` become <code> elements.
  function appendRich(parent, text) {
    var parts = text.split("`");
    for (var i = 0; i < parts.length; i++) {
      if (!parts[i]) {
        continue;
      }
      parent.appendChild(i % 2 ? el("code", "", parts[i]) : document.createTextNode(parts[i]));
    }
  }

  function setStatus(title, body) {
    status.textContent = "";
    if (title) {
      status.appendChild(el("p", "search-status-title", title));
    }
    if (body) {
      var p = el("p");
      appendRich(p, body);
      status.appendChild(p);
    }
  }

  function announce(text) {
    if (live) {
      live.textContent = text;
    }
  }

  function clearResults() {
    results = [];
    activeIndex = -1;
    list.textContent = "";
    input.setAttribute("aria-expanded", "false");
    input.setAttribute("aria-activedescendant", "");
  }

  function load() {
    if (items || loading) {
      return loading || Promise.resolve();
    }
    setStatus("", "Loading the search index…");
    loading = fetch(list.getAttribute("data-index"))
      .then(
        function (res) {
          if (!res.ok) {
            throw new Error("index");
          }
          return res.json().catch(function () {
            throw new Error("index");
          });
        },
        function () {
          throw new Error("server");
        }
      )
      .then(function (data) {
        items = buildItems(data);
        loadError = "";
      })
      .catch(function (err) {
        loadError = err && err.message === "server" ? "server" : "index";
      })
      .then(function () {
        loading = null;
        update();
      });
    return loading;
  }

  // buildItems flattens the index: one item per page (title hit) and one
  // per section entry (heading and text hits).
  function buildItems(data) {
    if (!data || !Array.isArray(data.p) || !Array.isArray(data.e)) {
      throw new Error("index");
    }
    var out = [];
    data.p.forEach(function (page) {
      out.push({ url: page.u, title: page.t, section: page.s, heading: page.t, text: "", pageHit: true });
    });
    data.e.forEach(function (entry) {
      var page = data.p[entry.p];
      if (!page) {
        return;
      }
      out.push({
        url: page.u + (entry.a ? "#" + entry.a : ""),
        title: page.t,
        section: page.s,
        heading: entry.h || page.t,
        text: entry.x || "",
        pageHit: false
      });
    });
    return out;
  }

  function tokenize(q) {
    return q.toLowerCase().split(/\s+/).filter(Boolean);
  }

  // search ranks with AND-token matching: a title hit outranks a heading
  // hit, which outranks a text hit.
  function search(tokens) {
    var scored = [];
    for (var i = 0; i < items.length; i++) {
      var it = items[i];
      var title = it.title.toLowerCase();
      var heading = it.pageHit ? "" : it.heading.toLowerCase();
      var text = it.text.toLowerCase();
      var score = 0;
      var all = true;
      for (var j = 0; j < tokens.length; j++) {
        var t = tokens[j];
        var s = 0;
        if (title.indexOf(t) >= 0) {
          s += 100;
        }
        if (heading.indexOf(t) >= 0) {
          s += 10;
        }
        if (text.indexOf(t) >= 0) {
          s += 1;
        }
        if (!s) {
          all = false;
          break;
        }
        score += s;
      }
      if (all) {
        if (it.pageHit) {
          score += 5;
        }
        scored.push({ item: it, score: score, order: i });
      }
    }
    scored.sort(function (a, b) {
      return b.score - a.score || a.order - b.order;
    });
    return scored.slice(0, MAX_RESULTS).map(function (s) {
      return s.item;
    });
  }

  // appendMarked appends text with every token occurrence wrapped in a
  // <mark> element.
  function appendMarked(parent, text, tokens) {
    var lower = text.toLowerCase();
    var pos = 0;
    while (pos < text.length) {
      var best = -1;
      var len = 0;
      for (var i = 0; i < tokens.length; i++) {
        var at = lower.indexOf(tokens[i], pos);
        if (at >= 0 && (best < 0 || at < best || (at === best && tokens[i].length > len))) {
          best = at;
          len = tokens[i].length;
        }
      }
      if (best < 0) {
        parent.appendChild(document.createTextNode(text.slice(pos)));
        return;
      }
      if (best > pos) {
        parent.appendChild(document.createTextNode(text.slice(pos, best)));
      }
      parent.appendChild(el("mark", "", text.slice(best, best + len)));
      pos = best + len;
    }
  }

  // excerpt starts the text near its first match.
  function excerpt(text, tokens) {
    var lower = text.toLowerCase();
    var first = -1;
    tokens.forEach(function (t) {
      var at = lower.indexOf(t);
      if (at >= 0 && (first < 0 || at < first)) {
        first = at;
      }
    });
    if (first > 60) {
      var start = text.lastIndexOf(" ", first - 40);
      return "…" + text.slice(start > 0 ? start + 1 : first - 40);
    }
    return text;
  }

  function render(tokens) {
    clearResults();
    results = search(tokens);
    if (!results.length) {
      setStatus('No results for "' + input.value.trim() + '"', "Check the spelling, or try a shorter term such as a module or command name.");
      announce("No results");
      return;
    }
    setStatus("", "");
    results.forEach(function (it, i) {
      var li = el("li", "search-result");
      li.id = "search-result-" + i;
      li.setAttribute("role", "option");
      li.setAttribute("aria-selected", "false");
      li.appendChild(el("div", "search-result-path", it.section + " › " + it.title));
      var heading = el("div", "search-result-heading");
      appendMarked(heading, it.heading, tokens);
      li.appendChild(heading);
      if (it.text) {
        var ex = el("div", "search-result-excerpt");
        appendMarked(ex, excerpt(it.text, tokens), tokens);
        li.appendChild(ex);
      }
      li.addEventListener("click", function () {
        go(i);
      });
      li.addEventListener("mousemove", function () {
        setActive(i);
      });
      list.appendChild(li);
    });
    input.setAttribute("aria-expanded", "true");
    setActive(0);
    announce(results.length === 1 ? "1 result" : results.length + " results");
  }

  function setActive(i) {
    var rows = list.children;
    if (!rows.length) {
      return;
    }
    if (activeIndex >= 0 && rows[activeIndex]) {
      rows[activeIndex].setAttribute("aria-selected", "false");
    }
    activeIndex = (i + rows.length) % rows.length;
    var row = rows[activeIndex];
    row.setAttribute("aria-selected", "true");
    input.setAttribute("aria-activedescendant", row.id);
    if (row.scrollIntoView) {
      row.scrollIntoView({ block: "nearest" });
    }
  }

  function go(i) {
    var it = results[i];
    if (!it) {
      return;
    }
    dialog.close();
    window.location.href = it.url;
  }

  function update() {
    try {
      window.sessionStorage.setItem(QUERY_KEY, input.value);
    } catch (e) {
      // Session-only query is optional.
    }
    if (loadError === "server") {
      clearResults();
      setStatus("", "Search needs a web server. Run `summer docs:serve` and open the address it prints.");
      return;
    }
    if (loadError === "index") {
      clearResults();
      setStatus("", "The search index could not be loaded. Reload the page to try again.");
      return;
    }
    if (!items) {
      clearResults();
      setStatus("", "Loading the search index…");
      return;
    }
    var tokens = tokenize(input.value);
    if (!tokens.length) {
      clearResults();
      setStatus("Search the documentation", "Type a module name, a command or a topic, for example `surf`, `migrate` or `relations`.");
      announce("");
      return;
    }
    render(tokens);
  }

  function open() {
    if (dialog.open) {
      return;
    }
    dialog.showModal();
    input.focus();
    input.select();
    if (!items && !loadError) {
      load();
    }
    update();
  }

  if (trigger) {
    trigger.addEventListener("click", open);
  }

  dialog.addEventListener("close", function () {
    if (trigger) {
      trigger.focus();
    }
  });

  // A click on the backdrop (outside the dialog box) closes the dialog.
  dialog.addEventListener("click", function (e) {
    if (e.target === dialog) {
      dialog.close();
    }
  });

  input.addEventListener("input", update);

  input.addEventListener("keydown", function (e) {
    if (e.key === "ArrowDown") {
      e.preventDefault();
      setActive(activeIndex + 1);
    } else if (e.key === "ArrowUp") {
      e.preventDefault();
      setActive(activeIndex - 1);
    } else if (e.key === "Enter") {
      e.preventDefault();
      go(activeIndex);
    }
  });

  function inTextField(target) {
    if (!target) {
      return false;
    }
    var tag = target.tagName;
    return tag === "INPUT" || tag === "TEXTAREA" || tag === "SELECT" || target.isContentEditable;
  }

  document.addEventListener("keydown", function (e) {
    if ((e.metaKey || e.ctrlKey) && !e.altKey && (e.key === "k" || e.key === "K")) {
      e.preventDefault();
      open();
    } else if (e.key === "/" && !e.metaKey && !e.ctrlKey && !e.altKey && !inTextField(e.target) && !dialog.open) {
      e.preventDefault();
      open();
    }
  });
})();