document.addEventListener("DOMContentLoaded", () => {

let data = { // Default
  current: "",
  pages: [
    {body: "It was a dark and stormy night.\n\nAll was quiet.", choices: [[1,"Continue"]], paths: []},
    {body: "Or was it...?", choices: [], paths: ["1"]}
  ],
  paths: {"":0, "1":1}
};

let state = {
  editing: false,
  saveinterval: 0,
  addcount: 0,
  path: ""
};

const db = new Dexie("vanguard-editor");
db.version(1).stores({files:"name"});
db.on("populate", () => db.files.add({name: "main", data}));
db.files.get("main").then(d => { data = d.data;
  location.hash = "#/"+data.current;
  state.path = renderPath();
  setTimeout(() => document.documentElement.scrollTop =
    document.getElementById("main").lastChild.offsetTop);
}).catch(e => console.error);

function download(a, text, name, type) {
  const file = new Blob([text], {type: type});
  a.href = URL.createObjectURL(file);
  a.download = name;
}

const prettyDate = d => d.getFullYear() +
  (d.getMonth()+1).toString().padStart(2, "0") +
  d.getDate().toString().padStart(2, "0") + "-" +
  d.getHours().toString().padStart(2, "0") +
  d.getMinutes().toString().padStart(2, "0") +
  d.getSeconds().toString().padStart(2, "0");

document.getElementById("save").addEventListener("mouseover", e => {
  download(e.target, JSON.stringify(data),
    `Vanguard-${prettyDate(new Date())}.json`,
    "application/json");
});

document.getElementById("open-file").addEventListener("change", e => {
  const r = new FileReader();
  r.onload = () => { try {
    data = JSON.parse(r.result);
    db.files.put({name:"main",data});
    location.hash = "#/"+data.current;
    state.path = renderPath();
    setTimeout(() => document.documentElement.scrollTop =
      document.getElementById("main").lastChild.offsetTop);
  } catch(e) { alert(e);
  }}; r.readAsText(e.target.files[0]);
});

const viewtpl = document.getElementById("view-entry").content;
const edittpl = document.getElementById("edit-entry").content;
const choicetpl = document.getElementById("edit-choice").content;

function renderView(path, choice) {
  const pageid = data.paths[path];
  const page = data.pages[pageid];
  const e = document.createElement("section");
  e.appendChild(viewtpl.cloneNode(true));

  e.querySelector("a").href = path? `#/${path}/edit` : "#/edit";
  e.querySelector("h2").innerHTML = path? (page.paths.length? `#${pageid} / ` +
    page.paths.map(p => `<a href="#/${p}"${p==path?' class="active"':""}>${p}</a>`)
      .join(" / ") : "UNREACHABLE") : "<a href='#/'>Start</a>";
  e.innerHTML += markup(page.body);
  if (!page.choices.length) e.innerHTML += "<h3 id='the-end'></h3>";
  else if (choice) e.innerHTML += `<a class="choice-made" href="#/${path}">${markup(page.choices[choice-1][1])}</a>`;
  else e.innerHTML += page.choices.map((c,i) =>
    `<a class="choice" href="#/${path}${path?"-":""}${i+1}">${markup(c[1])}</a>`).join("");

  return e;
}

function renderEdit(path) {
  const pageid = data.paths[path];
  const page = data.pages[pageid];
  const e = document.createElement("section");
  e.appendChild(edittpl.cloneNode(true));

  e.classList.add("editing");
  e.querySelector("a").href = `#/${path}`;
  e.querySelector("h2").innerHTML = path? (page.paths.length? `#${pageid} / ` +
    page.paths.map(p => `<a href="#/${p}"${p==path?' class="active"':""}>${p}</a>`)
      .join(" / ") : "UNREACHABLE") : "<a href='#/'>Start</a>";
  e.querySelector("textarea").value = page.body;

  page.choices.forEach(c => {
    const l = document.createElement("div");
    l.appendChild(choicetpl.cloneNode(true));
    l.classList.add("choice");
    l.querySelector("textarea").value =
      `#${c[0]}: ${c[1]}`;

    l.querySelector(".choice-delete").addEventListener("click",
      () => l.parentNode.removeChild(l));

    e.querySelector(".choices").appendChild(l);
  });

  e.querySelector(".add-choice").addEventListener("click", () => {
    const l = document.createElement("div");
    l.appendChild(choicetpl.cloneNode(true));
    l.classList.add("choice");

    const t = l.querySelector("textarea");
    t.value = `#${data.pages.length + (state.addcount++)}: Choice text...`;
    window.addEventListener("resize", () => resizeTA(t));
    t.addEventListener("input", () => resizeTA(t));
    l.querySelector(".choice-delete").addEventListener("click",
      () => l.parentNode.removeChild(l));

    e.querySelector(".choices").appendChild(l);
    resizeTA(t);
    t.focus();
  });

  return e;
};

function resizeTA(e) {
  const c = e.parentNode;
  c.style.height = c.scrollHeight + "px";
  e.style.height = "";
  e.style.height = e.scrollHeight + "px";
  c.style.height = "";
}

function renderPath() {
  let path = location.hash.slice(2);
  const main = document.getElementById("main");
  const o = main.cloneNode(false);

  state.addcount = 0;
  state.editing = path.endsWith("edit");
  if (state.editing) path = path.slice(0,-5);
  if (!/[0-9]+(-[0-9]+)*/.test(path)) path = "";

  const pieces = path.split("-");
  if (pieces[0]) for (let i=0; i<pieces.length; i++) {
    if (!data.paths.hasOwnProperty(pieces.slice(0,i+1).join("-"))) {
      return location.hash = "#/"+pieces.slice(0,i).join("-"); }
    o.appendChild(renderView(pieces.slice(0,i).join("-"), +pieces[i]))
  }

  if (state.editing) o.appendChild(renderEdit(path));
  else o.appendChild(renderView(path));

  main.parentNode.replaceChild(o, main);
  data.current = path;
  db.files.put({name:"main",data});

  if (state.editing) {
    [].forEach.call(document.querySelectorAll("textarea"), e => {
      e.addEventListener("input", () => resizeTA(e));
      window.addEventListener("resize", () => resizeTA(e));
      resizeTA(e);
    });

    document.getElementById("body").focus();

    state.saveinterval = setInterval(() => {
      const path = state.path;
      const pageid = data.paths[path];
      const page = data.pages[pageid];
      page.body = document.getElementById("body").value;
      db.files.put({name:"main",data});
    }, 15000);
  }

  const pageArr = new Array(data.pages.length).fill(0);
  Object.values(data.paths).forEach(p => pageArr[p] = 1);
  const unreach = pageArr.reduce((a,e,i) => { if (!e) a.push(i); return a; }, [])
  if (unreach.length) { //console.error("Unreachable", unreach);
    document.getElementById("unreachable").innerHTML = "Unreachable: " +
      unreach.map(u => "#"+u).join(", ");
  } else document.getElementById("unreachable").innerHTML = "";

  return path;
}

window.addEventListener("hashchange", () => {
  if (state.error) { delete state.error; return; }
  clearInterval(state.saveinterval);
  try {
    if (state.editing) {
      const path = state.path;
      const pageid = data.paths[path];
      const page = data.pages[pageid];
      page.body = document.getElementById("body").value;

      let newid = 0;
      const newidmap = {};
      page.choices = Array.from(document.querySelectorAll(".choice")).reduce((a,c,i) => {
        const v = c.querySelector("textarea").value;
        if (!/^#[0-9]+: /.test(v)) throw new Error("Invalid choice destination");

        a.push([+v.slice(1, v.indexOf(":")), v.slice(v.indexOf(" ")+1)]);
        return a;
      }, []).map(c => { const id = c[0];
        if (id < data.pages.length) return c;
        if (newidmap[id]) return [newidmap[id], c[1]];
        return [newidmap[id] = data.pages.length + newid++, c[1]];
      });

      const newpaths = {};
      data.pages.forEach(p => p.paths = []);

      page.choices.forEach((c,i) => {
        const id = c[0];
        if (id == data.pages.length) {
          data.pages.push({body: "Page content...", choices: [], paths: []});
        } else if (id > data.pages.length) throw new Error("ID Overflow");
      });

      function walkTree(id, path) {
        const page = data.pages[id];
        page.paths.forEach(p => {
          if (path.startsWith(p))
            throw new Error("Link loop detected"); });
        page.paths.push(path);
        page.choices.forEach((c,i) =>
          walkTree(c[0], path+(path?"-":"")+(i+1)));
        newpaths[path] = id;
      } walkTree(0, "");

      data.paths = newpaths;

      db.files.put({name:"main",data});
    }

    const oldscroll = document.documentElement.scrollTop;
    const oldoff = document.getElementById("main").lastChild.offsetTop;
    const oldid = data.paths[state.path];
    const newpath = renderPath();
    const newid = data.paths[newpath];

    if (newid == oldid) {
      const newoff = document.getElementById("main").lastChild.offsetTop;
      document.documentElement.scrollTop = newoff - (oldoff - oldscroll)
    }

    state.path = newpath;

  } catch(e) {
    state.error = 1;
    console.error(e); alert(e);
    location.hash = "#/"+state.path+(state.path?"/":"")+"edit";
  }
}, true);

const invertCookie = encodeURIComponent("vanguard-invert");
if (new RegExp("(?:^|;\\s*)"+invertCookie.replace(/[\-\.\+\*]/g,"\\$&")+"\\s*\\=").test(document.cookie))
  document.documentElement.classList.add("invert");
document.getElementById("theme").addEventListener("click", () =>
  document.cookie = invertCookie +
    (document.documentElement.classList.toggle("invert")?
      "=1; expires=Fri, 31 Dec 9999 23:59:59 GMT" :
       "=; expires=Thu, 01 Jan 1970 00:00:00 GMT"));

});