import { el, clear, onTeardown } from '../lib/dom.js';
import { loadSnapshot } from '../data/snapshot.js';
import { settings } from '../store/settings.js';
import { ui } from '../store/ui.js';
import { getPokemon } from '../data/api.js';
import { prettify } from '../data/pokedex-resolver.js';
import { Sprite } from '../components/Sprite.js';
import { openPokemonPicker } from '../components/PokemonPicker.js';
import { segThumb } from '../lib/anim.js';

const EGG_LABEL = {
  water1: 'Water 1', water2: 'Water 2', water3: 'Water 3',
  ground: 'Field', humanshape: 'Human-Like', indeterminate: 'Amorphous',
  plant: 'Grass', 'no-eggs': 'Undiscovered', ditto: 'Ditto',
};
const eggLabel = (g) => EGG_LABEL[g] || prettify(g);
const idFromUrl = (u) => Number(u.replace(/\/$/, '').split('/').pop());

export async function BreedingView() {
  const view = el('section', { class: 'view lookup breedview' });
  const snap = await loadSnapshot();
  const style = settings.get().spriteStyle;
  const vg = settings.get().versionGroup;

  const groups = [...new Set(snap.species.flatMap((s) => s.eggGroups || []))]
    .filter((g) => g !== 'no-eggs')
    .sort((a, b) => eggLabel(a).localeCompare(eggLabel(b)));

  let mode = ui.get().breedMode === 'compat' ? 'compat' : 'groups';
  let group = groups.includes(ui.get().breedGroup) ? ui.get().breedGroup : groups[0];
  let target = snap.speciesById.get(ui.get().breedTarget) || null;

  const SEG = [
    ['groups', 'Egg groups'],
    ['compat', 'Can breed with'],
  ];
  const seg = el(
    'div',
    { class: 'seg' },
    ...SEG.map(([id, label], i) =>
      el(
        'button',
        {
          type: 'button',
          class: `seg__btn${id === mode ? ' is-active' : ''}`,
          onclick: () => {
            mode = id;
            ui.set({ breedMode: id });
            seg
              .querySelectorAll('.seg__btn')
              .forEach((b, j) => b.classList.toggle('is-active', SEG[j][0] === id));
            setThumb(i);
            render();
          },
        },
        label,
      ),
    ),
  );
  const setThumb = segThumb(seg, SEG.length, Math.max(0, SEG.findIndex(([id]) => id === mode)));

  const body = el('div', { class: 'breedview__body' });

  function monGrid(list) {
    return list.length
      ? el(
          'div',
          { class: 'ab-mons' },
          ...list.map((sp) =>
            el(
              'a',
              { class: 'ab-mon', href: `#/pokemon/${sp.id}` },
              Sprite(sp.id, { style, alt: sp.name, size: 48 }),
              el('span', {}, sp.name.replace(/-/g, ' ')),
            ),
          ),
        )
      : el('p', { class: 'detail__muted' }, 'None.');
  }

  function renderGroups() {
    const chips = el(
      'div',
      { class: 'breed__chips' },
      ...groups.map((g) =>
        el(
          'button',
          {
            type: 'button',
            class: `breed__chip${g === group ? ' is-on' : ''}`,
            onclick: () => {
              group = g;
              ui.set({ breedGroup: g });
              render();
            },
          },
          eggLabel(g),
        ),
      ),
    );
    const list = snap.species
      .filter((s) => (s.eggGroups || []).includes(group))
      .sort((a, b) => a.id - b.id);
    body.append(
      chips,
      el('h2', { class: 'ppanel__sub' }, `${eggLabel(group)} (${list.length})`),
      monGrid(list),
    );
  }

  function renderCompat() {
    const slot = el(
      'button',
      {
        type: 'button',
        class: 'breed__pick',
        onclick: () =>
          openPokemonPicker(
            (id) => {
              target = snap.speciesById.get(id);
              ui.set({ breedTarget: id });
              render();
            },
            { closeAfterPick: true },
          ),
      },
      target
        ? el('span', {}, Sprite(target.id, { style, size: 40, alt: target.name }), ` ${prettify(target.name)}`)
        : 'Choose a Pokémon…',
    );
    body.append(slot);
    if (!target) return;

    const tGroups = new Set(target.eggGroups || []);
    if (tGroups.has('no-eggs')) {
      body.append(el('p', { class: 'detail__muted' }, `${prettify(target.name)} is in the Undiscovered egg group — it can’t be bred.`));
      return;
    }
    const isDitto = tGroups.has('ditto');
    const genderless = target.genderRate === -1;

    let list;
    if (isDitto) {
      list = snap.species.filter((s) => !s.eggGroups.includes('no-eggs') && !s.eggGroups.includes('ditto'));
    } else if (genderless) {
      list = snap.species.filter((s) => (s.eggGroups || []).includes('ditto'));
    } else {
      list = snap.species.filter((s) => {
        if (s.id === target.id) return false;
        if ((s.eggGroups || []).includes('ditto')) return true;
        if ((s.eggGroups || []).includes('no-eggs')) return false;
        return (s.eggGroups || []).some((g) => tGroups.has(g) && g !== 'ditto');
      });
    }
    list.sort((a, b) => a.id - b.id);

    const note = genderless
      ? 'Genderless — can only breed with Ditto.'
      : isDitto
        ? 'Ditto breeds with any Pokémon that can breed.'
        : `Egg groups: ${[...tGroups].map(eggLabel).join(', ')}. Needs an opposite-gender partner (or Ditto).`;

    // Egg moves belong to the family's lowest breeding stage (Pichu, not
    // Pikachu) — walk down the evolves-from chain.
    let base = target;
    while (base.evolvesFromId) {
      const prev = snap.speciesById.get(base.evolvesFromId);
      if (!prev) break;
      base = prev;
    }
    const eggMovesBox = el('div', { class: 'breed__eggmoves' }, el('p', { class: 'detail__muted' }, 'Loading egg moves…'));
    getPokemon(base.id)
      .then((pk) => {
        const eggMoves = pk.moves.filter((m) =>
          m.version_group_details.some(
            (d) => d.move_learn_method.name === 'egg' && (vg === 'all' || d.version_group.name === vg),
          ),
        );
        clear(eggMovesBox);
        if (!eggMoves.length) {
          eggMovesBox.append(el('p', { class: 'detail__muted' }, 'No egg moves for this game.'));
          return;
        }
        eggMovesBox.append(
          el(
            'h3',
            { class: 'ppanel__sub' },
            `Egg moves (${eggMoves.length})${base.id !== target.id ? ` — hatches as ${prettify(base.name)}` : ''}`,
          ),
          el(
            'p',
            { class: 'detail__muted' },
            'A parent that knows one of these passes it down. Open a move to see which Pokémon can learn it.',
          ),
          el(
            'div',
            { class: 'breed__eggmove-list' },
            ...eggMoves.map((m) =>
              el('a', { class: 'link', href: `#/move/${idFromUrl(m.move.url)}` }, m.move.name.replace(/-/g, ' ')),
            ),
          ),
        );
      })
      .catch(() => clear(eggMovesBox).append(el('p', { class: 'detail__muted' }, 'Egg moves unavailable offline.')));

    body.append(
      el('p', { class: 'breed__note' }, note),
      eggMovesBox,
      el('h2', { class: 'ppanel__sub' }, `Compatible partners (${list.length})`),
      monGrid(list),
    );
  }

  function render() {
    clear(body);
    if (mode === 'groups') renderGroups();
    else renderCompat();
  }

  clear(view).append(
    el('nav', { class: 'lookup__nav' }, el('a', { class: 'link', href: '#/team' }, '‹ Team')),
    el(
      'header',
      { class: 'view__header' },
      el('h1', {}, 'Breeding'),
      el('p', {}, 'Egg-group members and who a Pokémon can produce eggs with.'),
    ),
    seg,
    body,
  );
  render();

  onTeardown(view, () => {});
  return view;
}