import { useState, useMemo, useEffect } from 'react';
import type { Transaction } from '../data/mockData';
import type { TransactionArc } from '../data/arcData';

export interface TimeFrame {
  label: string;
  from: number; // Unix ms
  to: number;   // Unix ms
}

function buildFrames(periodDays: number): TimeFrame[] {
  const now = Date.now();
  const start = now - periodDays * 24 * 60 * 60 * 1000;

  const fmt = (ms: number, opts: Intl.DateTimeFormatOptions) =>
    new Date(ms).toLocaleDateString('fr-FR', opts);

  if (periodDays === 1) {
    return Array.from({ length: 24 }, (_, i) => {
      const from = start + i * 3_600_000;
      const to = from + 3_600_000;
      const h = new Date(from).getHours();
      return {
        label: `${fmt(from, { weekday: 'short', day: 'numeric', month: 'short' })} · ${h}h – ${h + 1}h`,
        from,
        to,
      };
    });
  }

  if (periodDays === 7) {
    return Array.from({ length: 7 }, (_, i) => {
      const from = start + i * 86_400_000;
      const to = from + 86_400_000;
      return {
        label: fmt(from, { weekday: 'long', day: 'numeric', month: 'short' }),
        from,
        to,
      };
    });
  }

  // 30 days → half-week frames (3.5 days ≈ 9–10 frames)
  const HALF_WEEK = 3.5 * 86_400_000;
  const frames: TimeFrame[] = [];
  let cursor = start;
  while (cursor < now) {
    const from = cursor;
    const to = Math.min(cursor + HALF_WEEK, now);
    frames.push({
      label: `${fmt(from, { weekday: 'short', day: 'numeric', month: 'short' })} – ${fmt(to - 1, { weekday: 'short', day: 'numeric', month: 'short' })}`,
      from,
      to,
    });
    cursor = to;
  }
  return frames;
}

export function useAnimation(transactions: Transaction[], arcs: TransactionArc[], periodDays: number, allTimestamps: number[] = []) {
  const [active, setActive] = useState(false);
  const [currentIndex, setCurrentIndex] = useState(0);
  const [playing, setPlaying] = useState(false);
  const [speed, setSpeed] = useState<1 | 2 | 4>(2);

  const frames = useMemo(() => buildFrames(periodDays), [periodDays]);

  // Reset cursor when period or activation changes.
  // Stop playback only on deactivation — not on activation, so activate() can
  // start playing immediately without being overridden by this effect.
  useEffect(() => {
    setCurrentIndex(0);
    if (!active) setPlaying(false);
  }, [periodDays, active]);

  // Auto-advance: one step every (2000 / speed) ms
  useEffect(() => {
    if (!playing || !active) return;
    const delay = 1500 / speed; // ×1=1500ms, ×2=750ms, ×4=375ms
    const t = setTimeout(() => {
      setCurrentIndex((i) => {
        if (i >= frames.length - 1) {
          setPlaying(false);
          return i;
        }
        return i + 1;
      });
    }, delay);
    return () => clearTimeout(t);
  }, [playing, active, currentIndex, speed, frames.length]);

  const visibleTransactions = useMemo(() => {
    if (!active || frames.length === 0) return transactions;
    const frame = frames[currentIndex];
    if (!frame) return transactions;
    return transactions.filter((t) => t.timestamp >= frame.from && t.timestamp < frame.to);
  }, [active, transactions, frames, currentIndex]);

  const visibleArcs = useMemo(() => {
    if (!active || frames.length === 0) return arcs;
    const frame = frames[currentIndex];
    if (!frame) return arcs;
    return arcs.filter((a) => a.timestamp >= frame.from && a.timestamp < frame.to);
  }, [active, arcs, frames, currentIndex]);

  // Nombre total de transfers (géo + non-géo) dans la frame courante
  const frameTotalCount = useMemo(() => {
    if (!active || frames.length === 0 || allTimestamps.length === 0) return null;
    const frame = frames[currentIndex];
    if (!frame) return null;
    return allTimestamps.filter((ts) => ts >= frame.from && ts < frame.to).length;
  }, [active, allTimestamps, frames, currentIndex]);

  return {
    active,
    activate: () => { setActive(true); setSpeed(1); setPlaying(true); },
    deactivate: () => { setActive(false); },
    playing,
    play: () => setPlaying(true),
    pause: () => setPlaying(false),
    currentIndex,
    seek: (i: number) => { setCurrentIndex(i); setPlaying(false); },
    speed,
    setSpeed,
    frames,
    currentFrame: frames[currentIndex] ?? null,
    visibleTransactions,
    visibleArcs,
    frameTotalCount,
  };
}