// views/split_view.js — Split-View: zwei nebeneinander gerenderte Views (links/rechts)

import { DEFAULT_TOP_INSET } from '../core/theme.js';
import {
  CHILD_VIEWS,
  computeMultiViewBaseLayout,
  drawEmptyPlot,
  drawMetersPanel,
  readMultiViewMeters,
  sanitizeChildId,
  sanitizePlotId,
  withClippedSubRect,
} from './multi_view_shared.js';

export const id = 'split-view';

const CONTENT_TOP = DEFAULT_TOP_INSET;
const CONTENT_BOTTOM = 0;

function readSplitMeters(CONFIG) {
  return readMultiViewMeters(CONFIG, 'SPLIT_VIEW');
}

function computeSplitLayout(rect, slots) {
  return computeMultiViewBaseLayout(rect, slots, CONTENT_TOP, CONTENT_BOTTOM);
}

function destroyChild(child) {
  if (!child || child.id === 'none') return;
  const mod = CHILD_VIEWS[child.id];
  if (mod && typeof mod.destroy === 'function') {
    try { mod.destroy(child.state); } catch (e) { console.warn('Split child destroy error:', e); }
  }
}

function initChild(env, childId) {
  const id = sanitizeChildId(childId, 'none');
  if (id === 'none') return { id: 'none', state: {} };
  const mod = CHILD_VIEWS[id];
  const state = (mod && typeof mod.init === 'function') ? (mod.init(env) || {}) : {};
  return { id, state };
}

function resizeChild(env, rect, child) {
  if (!child || child.id === 'none') return;
  const mod = CHILD_VIEWS[child.id];
  if (!mod || typeof mod.resize !== 'function') return;
  try { mod.resize({ rect }, child.state); } catch (e) { console.warn('Split child resize error:', e); }
}

async function renderChild(env, rect, child) {
  const { ctx: g } = env;
  if (!child || child.id === 'none') return;
  const mod = CHILD_VIEWS[child.id];
  if (!mod || typeof mod.render !== 'function') return;
  await withClippedSubRect(g, rect, async () => {
    const plotOnlySlots = (viewId) => {
      if (viewId === 'peak-history' || viewId === 'classic-needles' || viewId === 'panel') {
        const configured = env?.slots?.(viewId);
        if (Array.isArray(configured) && configured.length) return configured;
      }
      if (viewId === 'peak-history') return ['ppm-din'];
      if (viewId === 'classic-needles') return ['vu'];
      if (viewId === 'panel') return ['vu', 'ppm-ebu', 'ppm-din', 'tp', 'rms'];
      return ['none'];
    };
    const subEnv = Object.assign({}, env, {
      rect: { x: 0, y: 0, w: rect.w, h: rect.h },
      embedded: true,
      containerView: 'split-view',
      slots: plotOnlySlots,
      embeddedOffsetX: rect.x,
      embeddedOffsetY: rect.y,
    });
    await mod.render(subEnv, child.state);
  });
}

export function init(env) {
  const leftId = sanitizePlotId(env?.config?.SPLIT_VIEW_LEFT, 'phase-wheel');
  const rightId = sanitizePlotId(env?.config?.SPLIT_VIEW_RIGHT, 'realtime');
  const state = {
    staticLayers: new Map(),
    left: initChild(env, leftId),
    right: initChild(env, rightId),
    popup: initChild(env, 'none'),
    lastLeftId: leftId,
    lastRightId: rightId,
    lastPopupId: 'none',
    lastRectSig: '',
  };
  return state;
}

export function destroy(state) {
  if (state) state.staticLayers = null;
  destroyChild(state?.left);
  destroyChild(state?.right);
  destroyChild(state?.popup);
}

export function resize({ rect }, state) {
  if (!state || !rect) return;
  const sig = `${rect.w}x${rect.h}`;
  if (state.lastRectSig === sig) return;
  state.lastRectSig = sig;
  const layout = computeLayout(rect);
  resizeChild(null, { x: 0, y: 0, w: layout.left.w, h: layout.left.h }, state.left);
  resizeChild(null, { x: 0, y: 0, w: layout.right.w, h: layout.right.h }, state.right);
  resizeChild(null, { x: 0, y: 0, w: rect.w, h: rect.h }, state.popup);
}

function computeLayout(rect) {
  const gap = OUTER_GAP;
  const w = Math.max(0, rect.w);
  const h = Math.max(0, rect.h);
  const half = Math.floor((w - gap) / 2);
  const left = { x: 0, y: 0, w: Math.max(0, half), h };
  const right = { x: Math.max(0, half + gap), y: 0, w: Math.max(0, w - (half + gap)), h };
  return { left, right, gap };
}

export async function render(env, state) {
  const { ctx: g, rect, config: CONFIG } = env;
  const popupCfg = env?.splitPopup;
  const popupWanted = popupCfg && popupCfg.open ? sanitizeChildId(popupCfg.viewId, 'none') : 'none';

  // Popup-Modus: rendere die View in Originalgröße (vollflächig),
  // ohne Split-Hintergrund/Layout. So sieht es exakt wie die Einzel-View aus.
  if (popupWanted !== 'none' && state) {
    if (state.lastPopupId !== popupWanted) {
      destroyChild(state.popup);
      state.popup = initChild(env, popupWanted);
      state.lastPopupId = popupWanted;
      resizeChild(null, { x: 0, y: 0, w: rect.w, h: rect.h }, state.popup);
    }
    state._splitHit = {
      contentY: 0,
      plots: null,
      meters: [],
      popupBox: { x: 0, y: 0, w: rect.w, h: rect.h },
    };
    const mod = CHILD_VIEWS[state.popup.id];
    if (mod && typeof mod.render === 'function') {
      const subEnv = Object.assign({}, env, {
        rect: { x: 0, y: 0, w: rect.w, h: rect.h },
        embedded: false,
      });
      await mod.render(subEnv, state.popup.state);
    }
    return;
  }

  if (state && state.lastPopupId !== 'none') {
    destroyChild(state.popup);
    state.popup = initChild(env, 'none');
    state.lastPopupId = 'none';
  }

  const desiredLeftId = sanitizePlotId(env?.config?.SPLIT_VIEW_LEFT, 'phase-wheel');
  const desiredRightId = sanitizePlotId(env?.config?.SPLIT_VIEW_RIGHT, 'realtime');

  if (state.lastLeftId !== desiredLeftId) {
    destroyChild(state.left);
    state.left = initChild(env, desiredLeftId);
    state.lastLeftId = desiredLeftId;
  }
  if (state.lastRightId !== desiredRightId) {
    destroyChild(state.right);
    state.right = initChild(env, desiredRightId);
    state.lastRightId = desiredRightId;
  }

  const slots = readSplitMeters(CONFIG);
  const layout = computeSplitLayout(rect, slots);
  const leftPlotRect = layout?.plots?.left || { x: 0, y: 0, w: Math.floor(rect.w / 2), h: rect.h };
  const rightPlotRect = layout?.plots?.right || { x: Math.floor(rect.w / 2), y: 0, w: rect.w - Math.floor(rect.w / 2), h: rect.h };
  if (state) {
    state._splitHit = {
      contentY: 0,
      plots: {
        left: { ...leftPlotRect, viewId: desiredLeftId },
        right: { ...rightPlotRect, viewId: desiredRightId },
      },
      meters: [layout?.meters?.left, layout?.meters?.center, layout?.meters?.right].filter(Boolean).map((r) => ({ ...r })),
      popupBox: null,
    };
  }

  if (state.left?.id === 'none') drawEmptyPlot(state, g, leftPlotRect, 'Links: (leer)');
  else await renderChild(env, leftPlotRect, state.left);

  if (state.right?.id === 'none') drawEmptyPlot(state, g, rightPlotRect, 'Rechts: (leer)');
  else await renderChild(env, rightPlotRect, state.right);

  if (layout?.meters?.left) await drawMetersPanel(env, state, layout.meters.left, layout.meterIds.left, layout.slotW);
  if (layout?.meters?.center) await drawMetersPanel(env, state, layout.meters.center, layout.meterIds.center, layout.slotW);
  if (layout?.meters?.right) await drawMetersPanel(env, state, layout.meters.right, layout.meterIds.right, layout.slotW);
}