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 { team, addToTeam, removeFromTeam, clearTeam, slot, MAX_TEAM } from '../store/team.js';
import { TYPES, defenseVector, multiplier } from '../data/type-chart.js';
import { typesForGen } from '../lib/type-resolve.js';
import { forGeneration } from '../components/MovesList.js';
import { getMove } from '../data/api.js';
import { statAt, calcDamage } from '../lib/damage-calc.js';
import { NATURES } from '../data/natures.js';
import { Sprite } from '../components/Sprite.js';
import { TypeChip } from '../components/TypeChip.js';
import { CompareTable } from '../components/CompareTable.js';
import { openPokemonPicker } from '../components/PokemonPicker.js';
import { segThumb } from '../lib/anim.js';

const prettify = (s) => s.replace(/-/g, ' ').replace(/\b\w/g, (c) => c.toUpperCase());
const loose = (s) =>
  s
    .toLowerCase()
    .replace(/[-\s]+/g, ' ')
    .trim();
const multClass = (m) =>
  m === 0 ? 'm0' : m === 0.25 ? 'm025' : m === 0.5 ? 'm05' : m === 2 ? 'm2' : m === 4 ? 'm4' : 'm1';
const multText = (m) => (m === 0.25 ? '¼' : m === 0.5 ? '½' : m === 1 ? '' : `${m}×`);
const effWord = (eff) =>
  eff === 0
    ? 'No effect'
    : eff >= 4
      ? '4× effective'
      : eff >= 2
        ? 'Super effective'
        : eff <= 0.25
          ? 'Barely effective'
          : eff <= 0.5
            ? 'Not very effective'
            : null;

export async function TeamView() {
  const view = el('section', { class: 'view teamview' });
  const snap = await loadSnapshot();
  const MODES = [
    ['coverage', 'Coverage'],
    ['compare', 'Compare'],
    ['calc', 'Calc'],
  ];
  let mode = MODES.some(([id]) => id === ui.get().teamMode) ? ui.get().teamMode : 'coverage';

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

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

  view.append(
    el(
      'header',
      { class: 'view__header' },
      el('h1', {}, 'Team'),
      el('p', {}, `Up to ${MAX_TEAM} Pokémon — check weaknesses, coverage and stats.`),
    ),
    el(
      'div',
      { class: 'teamview__bar' },
      seg,
      el(
        'nav',
        { class: 'teamview__refs', 'aria-label': 'Reference tools' },
        el(
          'a',
          { class: 'reflink', href: '#/natures' },
          el('span', { class: 'reflink__ico', 'aria-hidden': 'true' }, '✦'),
          'Natures',
        ),
        el(
          'a',
          { class: 'reflink', href: '#/types' },
          el('span', { class: 'reflink__ico', 'aria-hidden': 'true' }, '▦'),
          'Type chart',
        ),
        el(
          'a',
          { class: 'reflink', href: '#/breeding' },
          el('span', { class: 'reflink__ico', 'aria-hidden': 'true' }, '⬡'),
          'Breeding',
        ),
      ),
    ),
    lineup,
    body,
  );

  function members() {
    return team
      .get()
      .members.map((m) => {
        const s = slot(m);
        const base = snap.speciesById.get(s.id);
        if (!base) return null;
        const f = s.form && (base.forms || []).find((x) => x.slug === s.form);
        if (!f) return { ...base, _slotForm: null };
        // Merge the snapshot form's baked types / stats so coverage,
        // compare and the calc all analyse the form, not the base.
        return {
          ...base,
          _slotForm: s.form,
          name: `${base.name} (${f.name})`,
          spriteId: f.id,
          types: f.types || base.types,
          pastTypes: [],
          stats: f.stats || base.stats,
          bst: f.bst ?? base.bst,
        };
      })
      .filter(Boolean);
  }

  function renderLineup() {
    const mem = members();
    clear(lineup);
    const style = settings.get().spriteStyle;
    for (const sp of mem) {
      lineup.append(
        el(
          'div',
          { class: 'lineup__slot' },
          el(
            'button',
            {
              class: 'lineup__x',
              type: 'button',
              'aria-label': `Remove ${sp.name}`,
              onclick: () => {
                removeFromTeam(sp.id, sp._slotForm);
              },
            },
            '✕',
          ),
          el(
            'a',
            { href: `#/pokemon/${sp.id}`, class: 'lineup__link' },
            Sprite(sp.spriteId ?? sp.id, { style, alt: sp.name, size: 64 }),
            el('span', { class: 'lineup__name' }, sp.name.replace(/-/g, ' ')),
          ),
        ),
      );
    }
    if (mem.length < MAX_TEAM) {
      lineup.append(
        el(
          'button',
          {
            class: 'lineup__add',
            type: 'button',
            onclick: () => openPokemonPicker((id) => addToTeam(id), { closeAfterPick: true }),
          },
          '＋',
          el('span', {}, 'Add'),
        ),
      );
    }
    if (mem.length) {
      lineup.append(
        el(
          'button',
          { class: 'lineup__clear', type: 'button', onclick: () => clearTeam() },
          'Clear',
        ),
      );
    }
  }

  function render() {
    renderLineup();
    const mem = members();
    clear(body);
    if (mode === 'calc') {
      body.append(calcTool(mem));
      return;
    }
    if (!mem.length) {
      body.append(el('p', { class: 'detail__muted' }, 'Add some Pokémon to get started.'));
      return;
    }
    body.append(mode === 'coverage' ? coverage(mem) : compare(mem));
  }

  function coverage(mem) {
    const st = settings.get();
    const vg = snap.versionGroupByKey.get(st.versionGroup);
    const gen = vg ? vg.generation : 9;
    const gameLabel = st.versionGroup === 'all' ? 'all games' : prettify(st.versionGroup);
    const style = st.spriteStyle;

    // Only the types that exist in the selected game (no Fairy before Gen 6,
    // no Steel/Dark before Gen 2). Member typings are era-accurate too —
    // pre-Gen-6 Clefairy is Normal, Gen 1 Magnemite is pure Electric.
    const GEN_TYPES = TYPES.filter((t) => {
      if (t === 'fairy' && gen < 6) return false;
      if ((t === 'steel' || t === 'dark') && gen < 2) return false;
      return true;
    });
    const memTypes = mem.map((sp) => typesForGen(sp, gen));
    const vectors = memTypes.map((types) => defenseVector(types, gen));

    // Per attacking type: which members are weak, how many resist.
    const analysis = GEN_TYPES.map((t) => {
      const weak = [];
      let resist = 0;
      vectors.forEach((v, i) => {
        const m = v[t] ?? 1;
        if (m >= 2) weak.push({ sp: mem[i], m });
        else if (m < 1) resist += 1;
      });
      return { type: t, weak, weakN: weak.length, resist };
    });

    // A "weak spot": 2+ members weak, or someone weak and nobody resists it.
    const threats = analysis
      .filter((a) => a.weakN >= 2 || (a.weakN >= 1 && a.resist === 0))
      .sort((a, b) => b.weakN - a.weakN || a.resist - b.resist);
    const unresisted = analysis.filter((a) => a.weakN === 0 && a.resist === 0).map((a) => a.type);

    const weakSpots = threats.length
      ? el(
          'div',
          { class: 'weakspots' },
          ...threats.map((a) =>
            el(
              'div',
              { class: `weakspot${a.resist === 0 ? ' is-nores' : ''}` },
              TypeChip(a.type),
              el('span', { class: 'weakspot__count' }, `${a.weakN} weak`),
              a.resist === 0
                ? el('span', { class: 'weakspot__flag' }, '0 resist')
                : el('span', { class: 'weakspot__res' }, `${a.resist} resist`),
              el(
                'span',
                { class: 'weakspot__mem' },
                ...a.weak.map(({ sp, m }) =>
                  el(
                    'a',
                    {
                      class: 'weakspot__chip',
                      href: `#/pokemon/${sp.id}`,
                      title: `${prettify(sp.name)} takes ${m}×`,
                    },
                    Sprite(sp.spriteId ?? sp.id, { style, size: 26, alt: sp.name }),
                  ),
                ),
              ),
            ),
          ),
        )
      : el('p', { class: 'cov__ok' }, '✓ Nothing hits two or more of your team super-effectively.');

    // Defensive grid: a diverging bar (resists ◀ | ▶ weaknesses) makes the
    // rows to worry about jump out; threat rows get a tinted background.
    const head = el(
      'div',
      { class: 'cov__row cov__row--head' },
      el('span', { class: 'cov__type' }, ''),
      ...mem.map((sp) =>
        el(
          'a',
          { class: 'cov__mem', href: `#/pokemon/${sp.id}`, title: prettify(sp.name) },
          Sprite(sp.spriteId ?? sp.id, { style, size: 34, alt: sp.name }),
        ),
      ),
      el('span', { class: 'cov__bal cov__bal--head' }, 'resist · weak'),
    );
    const rows = GEN_TYPES.map((t) => {
      const a = analysis.find((x) => x.type === t);
      const cells = vectors.map((v) => {
        const m = v[t] ?? 1;
        return el('span', { class: `cov__cell ${multClass(m)}` }, multText(m));
      });
      const bal = el(
        'span',
        { class: 'cov__bal' },
        el(
          'span',
          { class: 'cov__bal-side cov__bal-side--l' },
          el('span', { class: 'cov__bal-res', style: `width:${Math.min(a.resist, 6) * 10}px` }),
        ),
        el(
          'span',
          { class: 'cov__bal-side cov__bal-side--r' },
          el(
            'span',
            { class: 'cov__bal-weak', style: `width:${Math.min(a.weakN, 6) * 10}px` },
            a.weakN || '',
          ),
        ),
      );
      return el(
        'div',
        { class: `cov__row${a.weakN >= 2 ? ' cov__row--threat' : ''}` },
        el('span', { class: 'cov__type' }, TypeChip(t)),
        ...cells,
        bal,
      );
    });

    // Offensive coverage gaps: defending types no member hits super-effectively
    const gaps = GEN_TYPES.filter(
      (def) => !mem.some((sp, i) => memTypes[i].some((atk) => multiplier(atk, [def], gen) >= 2)),
    );

    // Quick team stats
    const avgBst = Math.round(mem.reduce((s, m) => s + (m.bst || 0), 0) / mem.length);
    const fastest = mem.slice().sort((a, b) => (b.stats?.spe || 0) - (a.stats?.spe || 0))[0];
    const bulkiest = mem
      .slice()
      .sort(
        (a, b) =>
          (b.stats?.hp || 0) +
          (b.stats?.def || 0) +
          (b.stats?.spd || 0) -
          ((a.stats?.hp || 0) + (a.stats?.def || 0) + (a.stats?.spd || 0)),
      )[0];

    return el(
      'div',
      {},
      el('h2', { class: 'ppanel__sub' }, `Weak spots · ${gameLabel} (Gen ${gen})`),
      weakSpots,
      unresisted.length
        ? el(
            'p',
            { class: 'cov__unres' },
            el('span', { class: 'cov__unres-k' }, 'No resist to: '),
            el('span', { class: 'matchups__types' }, ...unresisted.map(TypeChip)),
          )
        : null,
      el('h2', { class: 'ppanel__sub' }, 'Full matchup grid'),
      el('div', { class: 'cov' }, head, ...rows),
      el('h2', { class: 'ppanel__sub' }, 'Offensive gaps (no super-effective STAB)'),
      gaps.length
        ? el('div', { class: 'matchups__types' }, ...gaps.map(TypeChip))
        : el('p', { class: 'detail__muted' }, 'Your team hits every type super-effectively. Nice.'),
      el('h2', { class: 'ppanel__sub' }, 'At a glance'),
      el(
        'dl',
        { class: 'pfacts' },
        fact('Average BST', String(avgBst)),
        fact('Fastest', monLink(fastest, `${fastest.stats?.spe ?? '?'} Spe`)),
        fact(
          'Bulkiest',
          monLink(
            bulkiest,
            `${(bulkiest.stats?.hp || 0) + (bulkiest.stats?.def || 0) + (bulkiest.stats?.spd || 0)} HP+Def+SpD`,
          ),
        ),
      ),
    );
  }

  function monLink(sp, tail) {
    return el(
      'span',
      {},
      el('a', { class: 'link', href: `#/pokemon/${sp.id}` }, prettify(sp.name)),
      ` (${tail})`,
    );
  }

  function compare(mem) {
    const vg = snap.versionGroupByKey.get(settings.get().versionGroup);
    const gen = vg ? vg.generation : 9;
    return el(
      'div',
      { class: 'teamcompare' },
      el(
        'p',
        { class: 'teamcompare__note' },
        'Your six side by side. ',
        el('a', { class: 'link', href: '#/compare' }, 'Compare any Pokémon →'),
      ),
      CompareTable(mem, { gen, style: settings.get().spriteStyle }),
    );
  }

  // ---- Damage calculator ------------------------------------------
  // Attacker + move vs. defender -> a damage range, using the standard
  // formula off base stats/level/nature/EVs. No items, abilities, weather
  // or terrain — those aren't part of this app's data model, so it's a
  // base-stats estimate rather than a battle-exact number.
  function calcTool(mem) {
    const st = settings.get();
    const vg = snap.versionGroupByKey.get(st.versionGroup);
    const gen = vg ? vg.generation : 9;
    const genOfVg = (name) => snap.versionGroupByKey.get(name)?.generation ?? 9;
    const style = st.spriteStyle;

    const state = {
      atk: mem[0] || null,
      def: mem[1] || mem[0] || null,
      move: null, // { id, name, ...current-gen snapshot fields }
      moveFull: null, // live /move/:id once fetched (adds past_values)
      level: 100,
      atkNature: 'Hardy',
      defNature: 'Hardy',
      atkEv: 0,
      defEv: 0,
      hpEv: 0,
      crit: false,
    };

    const natureOptions = NATURES.map((n) => [n.name, n.name]);

    function numField(label, value, { min = 0, max = 999 } = {}, onChange) {
      return el(
        'label',
        { class: 'calc__field' },
        el('span', {}, label),
        el('input', {
          type: 'number',
          min: String(min),
          max: String(max),
          value: String(value),
          onchange: (e) => {
            const n = Math.max(min, Math.min(max, Number(e.target.value) || 0));
            e.target.value = String(n);
            onChange(n);
            recalc();
          },
        }),
      );
    }

    function natureField(label, value, onChange) {
      return el(
        'label',
        { class: 'calc__field' },
        el('span', {}, label),
        el(
          'select',
          {
            onchange: (e) => {
              onChange(e.target.value);
              recalc();
            },
          },
          ...natureOptions.map(([v, t]) => el('option', { value: v, selected: v === value }, t)),
        ),
      );
    }

    function slot(which, sideLabel) {
      const holder = el('div', { class: 'calc__slot' });
      function paint() {
        const sp = state[which];
        clear(holder).append(
          sp
            ? el(
                'button',
                { type: 'button', class: 'calc__pick', onclick: () => pick() },
                Sprite(sp.spriteId ?? sp.id, { style, size: 48, alt: sp.name }),
                el('span', {}, prettify(sp.name)),
              )
            : el(
                'button',
                { type: 'button', class: 'calc__pick calc__pick--empty', onclick: () => pick() },
                `Choose ${sideLabel}…`,
              ),
        );
      }
      function pick() {
        openPokemonPicker((id) => {
          state[which] = snap.speciesById.get(id);
          paint();
          recalc();
        });
      }
      paint();
      const quick = mem.length
        ? el(
            'div',
            { class: 'calc__quick' },
            ...mem.map((sp) =>
              el(
                'button',
                {
                  type: 'button',
                  class: 'calc__quick-btn',
                  title: prettify(sp.name),
                  onclick: () => {
                    state[which] = sp;
                    paint();
                    recalc();
                  },
                },
                Sprite(sp.spriteId ?? sp.id, { style, size: 26, alt: sp.name }),
              ),
            ),
          )
        : null;
      return el(
        'div',
        { class: 'calc__side' },
        el('h3', { class: 'ppanel__sub' }, sideLabel),
        holder,
        quick,
      );
    }

    const atkSlot = slot('atk', 'Attacker');
    const defSlot = slot('def', 'Defender');

    const moveNote = el('span', { class: 'calc__move-note' });
    const moveDatalist = el(
      'datalist',
      { id: 'calc-movelist' },
      ...snap.moves.map((m) => el('option', { value: m.name.replace(/-/g, ' ') })),
    );
    const moveInput = el('input', {
      type: 'text',
      list: 'calc-movelist',
      class: 'calc__move-input',
      placeholder: 'Move…',
      onchange: (e) => {
        const q = loose(e.target.value);
        const hit = snap.moves.find((m) => loose(m.name) === q);
        state.move = hit || null;
        state.moveFull = null;
        e.target.value = hit ? hit.name.replace(/-/g, ' ') : '';
        recalc();
        if (hit) {
          getMove(hit.id)
            .then((full) => {
              if (state.move?.id !== hit.id) return; // superseded
              state.moveFull = full;
              recalc();
            })
            .catch(() => {});
        }
      },
    });

    const critField = el(
      'label',
      { class: 'calc__field calc__field--check' },
      el('input', {
        type: 'checkbox',
        onchange: (e) => {
          state.crit = e.target.checked;
          recalc();
        },
      }),
      'Critical hit',
    );

    const result = el('div', { class: 'calc__result' });

    function recalc() {
      const { atk, def } = state;
      moveNote.textContent = '';
      if (!state.move) {
        clear(result).append(el('p', { class: 'detail__muted' }, 'Pick a move.'));
        return;
      }
      const raw = state.moveFull || {
        power: state.move.power,
        accuracy: state.move.accuracy,
        type: { name: state.move.type },
        damage_class: state.move.damageClass ? { name: state.move.damageClass } : null,
        past_values: [],
      };
      const v = forGeneration(raw, gen, genOfVg);
      moveNote.textContent = `${prettify(v.type)} · ${v.damage_class ? prettify(v.damage_class) : 'Status'}${v.power ? ` · ${v.power} power` : ''}`;
      if (!atk || !def) {
        clear(result).append(
          el('p', { class: 'detail__muted' }, 'Choose an attacker and a defender.'),
        );
        return;
      }
      if (!v.damage_class || v.damage_class === 'status' || !v.power) {
        clear(result).append(
          el(
            'p',
            { class: 'detail__muted' },
            `${prettify(state.move.name)} doesn't deal direct damage.`,
          ),
        );
        return;
      }
      const statKey = v.damage_class === 'special' ? 'spa' : 'atk';
      const defKey = v.damage_class === 'special' ? 'spd' : 'def';
      const atkTypes = typesForGen(atk, gen);
      const defTypes = typesForGen(def, gen);
      const atkStat = statAt(atk.stats?.[statKey] ?? 0, state.level, {
        ev: state.atkEv,
        nature: state.atkNature,
        statKey,
      });
      const defStat = statAt(def.stats?.[defKey] ?? 0, state.level, {
        ev: state.defEv,
        nature: state.defNature,
        statKey: defKey,
      });
      const defHp = statAt(def.stats?.hp ?? 0, state.level, { ev: state.hpEv, statKey: 'hp' });
      const dmg = calcDamage({
        level: state.level,
        power: v.power,
        moveType: v.type,
        atkTypes,
        defTypes,
        atkStat,
        defStat,
        gen,
        crit: state.crit,
      });

      clear(result);
      if (!dmg) {
        result.append(el('p', { class: 'detail__muted' }, 'No power data for this move.'));
        return;
      }
      if (dmg.eff === 0) {
        result.append(
          el('p', { class: 'calc__headline' }, `${prettify(def.name)} is immune — no effect.`),
        );
        return;
      }
      const pctMin = (dmg.min / defHp) * 100;
      const pctMax = (dmg.max / defHp) * 100;
      const hitsMin = Math.ceil(100 / pctMax);
      const hitsMax = Math.ceil(100 / pctMin);
      const word = effWord(dmg.eff);
      result.append(
        el(
          'p',
          { class: 'calc__headline' },
          `${dmg.min}–${dmg.max} dmg`,
          el('span', { class: 'calc__pct' }, ` · ${pctMin.toFixed(1)}–${pctMax.toFixed(1)}% HP`),
        ),
        el(
          'p',
          { class: 'calc__sub' },
          hitsMin === hitsMax
            ? `${hitsMin} hit${hitsMin > 1 ? 's' : ''} to KO`
            : `${hitsMin}–${hitsMax} hits to KO`,
        ),
        el(
          'div',
          { class: 'calc__badges' },
          dmg.stab ? el('span', { class: 'calc__badge calc__badge--stab' }, 'STAB') : null,
          word
            ? el(
                'span',
                {
                  class: `calc__badge${dmg.eff >= 2 || dmg.eff === 4 ? ' calc__badge--up' : ' calc__badge--down'}`,
                },
                word,
              )
            : null,
        ),
      );
    }

    recalc();

    return el(
      'div',
      { class: 'calc' },
      el(
        'div',
        { class: 'calc__sides' },
        atkSlot,
        el('span', { class: 'calc__vs', 'aria-hidden': 'true' }, '⇄'),
        defSlot,
      ),
      moveDatalist,
      el('div', { class: 'calc__movebar' }, moveInput, moveNote),
      el(
        'div',
        { class: 'calc__controls' },
        numField('Level', state.level, { min: 1, max: 100 }, (n) => (state.level = n)),
        natureField('Attacker nature', state.atkNature, (v) => (state.atkNature = v)),
        numField('Attacker EV', state.atkEv, { min: 0, max: 252 }, (n) => (state.atkEv = n)),
        natureField('Defender nature', state.defNature, (v) => (state.defNature = v)),
        numField('Defender EV', state.defEv, { min: 0, max: 252 }, (n) => (state.defEv = n)),
        numField('Defender HP EV', state.hpEv, { min: 0, max: 252 }, (n) => (state.hpEv = n)),
        critField,
      ),
      result,
      el(
        'p',
        { class: 'calc__caveat' },
        'Estimate from base stats (31 IVs assumed) — items, abilities, weather and terrain aren’t modeled.',
      ),
    );
  }

  render();
  const off = team.subscribe(render);
  // Re-render on any settings change: sprite style feeds the lineup, and the
  // selected game drives the coverage generation + era typings.
  const offSettings = settings.subscribe(render);
  onTeardown(view, () => {
    off();
    offSettings();
  });
  return view;
}

function fact(k, v) {
  return el('div', { class: 'fact' }, el('dt', {}, k), el('dd', {}, v));
}