import { NOTE_PIN_ICON } from "/js/icons.js";
import { notifyGpxStoreChanged } from "/js/panels.js";

const NEW_LAYER_VALUE = "__new__";

// Every hand-drawn note (from here or measure.js's "Save as note") gets one
// of these — the only stable way to find a specific feature again for
// editing/deleting later (see GpxStore#update_feature/#delete_feature):
// array position shifts as other notes are added/removed, and the note's
// own text is exactly the thing an edit changes.
export function generateNoteId() {
  return typeof crypto !== "undefined" && crypto.randomUUID ? crypto.randomUUID() : `${Date.now()}-${Math.random().toString(36).slice(2)}`;
}

// The "note text + which .geojson layer" form, shared by NotesControl (a
// single click) and measure.js's "Save as note" button (its current
// distance/area shape) — extracted here rather than duplicated in both,
// since the two differ only in *what* the note attaches a location to,
// not in how it's captured or where it's saved. Renders into whatever
// container it's given (each caller owns where that sits in its own panel);
// hidden until open() is called.
export class NoteSaveForm {
  constructor(container, { onSaved, onCancel } = {}) {
    this._onSaved = onSaved;
    this._onCancel = onCancel;

    this._el = document.createElement("div");
    this._el.className = "notes-panel__form";
    this._el.hidden = true;
    this._el.innerHTML = `
      <textarea class="notes-panel__text" rows="2" placeholder="Note…"></textarea>
      <select class="notes-panel__target"></select>
      <input type="text" class="notes-panel__new-name" placeholder="Layer name" hidden>
      <div class="notes-panel__actions">
        <button type="button" class="notes-panel__save">Save</button>
        <button type="button" class="notes-panel__cancel">Cancel</button>
      </div>
    `;
    container.appendChild(this._el);

    this._text = this._el.querySelector(".notes-panel__text");
    this._target = this._el.querySelector(".notes-panel__target");
    this._newName = this._el.querySelector(".notes-panel__new-name");
    this._saveButton = this._el.querySelector(".notes-panel__save");

    this._target.addEventListener("change", () => {
      this._newName.hidden = this._target.value !== NEW_LAYER_VALUE;
      if (!this._newName.hidden) this._newName.focus();
    });
    this._saveButton.addEventListener("click", () => this._save());
    this._el.querySelector(".notes-panel__cancel").addEventListener("click", () => this.close(true));
  }

  get isOpen() {
    return !this._el.hidden;
  }

  async open(geometry) {
    this._geometry = geometry;
    this._el.hidden = false;
    this._text.value = "";
    this._text.focus();
    await this._populateTargets();
  }

  close(viaCancel = false) {
    this._geometry = null;
    this._el.hidden = true;
    this._newName.hidden = true;
    this._newName.value = "";
    if (viaCancel) this._onCancel?.();
  }

  async _populateTargets() {
    const previousValue = this._target.value;
    let files = [];
    try {
      const tree = await (await fetch("/api/gpx/tree")).json();
      files = geojsonFiles(tree);
    } catch (err) {
      // Tree fetch failed — target select just falls back to "new layer"
      // only, still usable.
    }

    this._target.innerHTML =
      files.map((file) => `<option value="${escapeAttr(file.path)}">${escapeText(file.path)}</option>`).join("") +
      `<option value="${NEW_LAYER_VALUE}">+ New layer…</option>`;
    this._target.value = files.some((file) => file.path === previousValue) ? previousValue : NEW_LAYER_VALUE;
    this._newName.hidden = this._target.value !== NEW_LAYER_VALUE;
  }

  async _save() {
    const text = this._text.value.trim();
    if (!text || !this._geometry) return;

    const isNewLayer = this._target.value === NEW_LAYER_VALUE;
    const name = isNewLayer ? this._newName.value.trim() : "";
    if (isNewLayer && !name) {
      this._newName.focus();
      return;
    }

    const feature = {
      type: "Feature",
      properties: { id: generateNoteId(), name: text, category: "Note", time: new Date().toISOString() },
      geometry: this._geometry,
    };

    const body = new URLSearchParams({ feature: JSON.stringify(feature) });
    if (isNewLayer) body.set("name", name);
    else body.set("path", this._target.value);

    this._saveButton.disabled = true;
    try {
      const response = await fetch("/api/gpx/notes", { method: "POST", body });
      if (!response.ok) throw new Error(`save failed: ${response.status}`);
      notifyGpxStoreChanged();
      this.close();
      this._onSaved?.();
    } catch (err) {
      window.alert("Could not save the note — check your connection and try again.");
    } finally {
      this._saveButton.disabled = false;
    }
  }
}

// A quick "pin it with a note" tool — click the map, write a short note,
// pick which .geojson "layer" file it joins (or start a new one). Point
// only: for a distance/area shape, draw it with the Measure tool and use
// its own "Save as note" button instead of duplicating that click-to-place
// UX here — see measure.js.
export class NotesControl {
  constructor() {
    this._active = false;
  }

  onAdd(map) {
    this._map = map;

    this._container = document.createElement("div");
    this._container.className = "maplibregl-ctrl maplibregl-ctrl-group notes-ctrl";
    this._container.innerHTML = `
      <button type="button" class="notes-ctrl__button" title="Add note" aria-label="Add note">${NOTE_PIN_ICON}</button>
      <div class="notes-panel" hidden>
        <p class="notes-panel__hint">Click the map to place a note.</p>
      </div>
    `;
    this._button = this._container.querySelector(".notes-ctrl__button");
    this._panel = this._container.querySelector(".notes-panel");
    this._hint = this._container.querySelector(".notes-panel__hint");

    this._form = new NoteSaveForm(this._panel, {
      onSaved: () => (this._hint.hidden = false),
      onCancel: () => (this._hint.hidden = false),
    });

    this._button.addEventListener("click", () => this._setActive(!this._active));

    this._onClick = (event) => {
      if (!this._active || this._form.isOpen) return;
      this._hint.hidden = true;
      this._form.open({ type: "Point", coordinates: [event.lngLat.lng, event.lngLat.lat] });
    };
    map.on("click", this._onClick);

    return this._container;
  }

  onRemove() {
    this._map.off("click", this._onClick);
    this._container.remove();
  }

  getDefaultPosition() {
    return "top-left";
  }

  _setActive(active) {
    this._active = active;
    this._button.classList.toggle("active", active);
    this._panel.hidden = !active;
    this._map.getCanvas().style.cursor = active ? "crosshair" : "";
    if (!active) this._form.close();
  }
}

function geojsonFiles(node, results = []) {
  if (node.type === "file" && node.path.toLowerCase().endsWith(".geojson")) {
    results.push({ path: node.path });
  }
  (node.children || []).forEach((child) => geojsonFiles(child, results));
  return results;
}

function escapeAttr(value) {
  return value.replace(/&/g, "&amp;").replace(/"/g, "&quot;");
}

function escapeText(value) {
  return value.replace(/&/g, "&amp;").replace(/</g, "&lt;");
}