import {
  DAY_PARTS,
  DEMO_CATEGORIES,
  FESTIVAL_DAYS,
  availabilityKey,
  dayPartHours,
} from '@/domain/festival';
import type { Assignment, AssignmentStatus, Position, Volunteer } from '@/domain/types';

import { buildPositions } from './positions';

export interface DemoDataset {
  positions: Position[];
  volunteers: Volunteer[];
  assignments: Assignment[];
  removed: { volunteerName: string; positionName: string; zone: string; dayShortLabel: string; dayPartLabel: string }[];
  nextAssignmentSeq: number;
}

// Générateur pseudo-aléatoire déterministe (mulberry32), repris du design pour
// obtenir exactement le même jeu de démonstration à chaque chargement.
function mulberry32(seed: number): () => number {
  let a = seed;
  return function () {
    a |= 0;
    a = (a + 0x6d2b79f5) | 0;
    let t = Math.imul(a ^ (a >>> 15), 1 | a);
    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
  };
}

const FIRST_NAMES = [
  'Camille', 'Yanis', 'Léa', 'Mathis', 'Soraya', 'Thomas', 'Awa', 'Julien', 'Chloé', 'Nadia',
  'Hugo', 'Inès', 'Baptiste', 'Manon', 'Karim', 'Élodie', 'Rémi', 'Sarah', 'Antoine', 'Fanny',
  'Malik', 'Clara', 'Victor', 'Jeanne',
];
const LAST_NAMES = [
  'Fournier', 'Berger', 'Moreau', 'Lambert', 'Benali', 'Rey', 'Diallo', 'Chevalier', 'Marchand',
  'Perrin', 'Lefèvre', 'Nguyen', 'Rossi', 'Garnier', 'Barbier', 'Vasseur', 'Colin', 'Prévost',
  'Renard', 'Dupuy',
];

const VOLUNTEER_COUNT = 64;
const NEVER_ASSIGNED_INDEXES = [7, 21, 34, 48, 55];
const OVERLOADED_INDEXES = [3, 9];

function statusFromRoll(roll: number): AssignmentStatus {
  if (roll < 0.72) return 'CONFIRMED';
  if (roll < 0.95) return 'PROPOSED';
  return 'DECLINED';
}

export function buildDemoDataset(): DemoDataset {
  const positions = buildPositions();
  const rnd = mulberry32(20260715);

  const volunteers: Volunteer[] = [];
  for (let i = 0; i < VOLUNTEER_COUNT; i += 1) {
    const firstName = FIRST_NAMES[i % FIRST_NAMES.length];
    const lastName = LAST_NAMES[(i * 7 + 3) % LAST_NAMES.length];
    const availability = new Set<string>();
    FESTIVAL_DAYS.forEach((day) => {
      DAY_PARTS.forEach((part) => {
        const isEdgeDay = day.index === 0 || day.index === 3;
        if (rnd() < (isEdgeDay ? 0.4 : 0.6)) {
          availability.add(availabilityKey(day.id, part.code));
        }
      });
    });
    const preferredCategories = [DEMO_CATEGORIES[Math.floor(rnd() * DEMO_CATEGORIES.length)]];
    if (rnd() < 0.45) {
      preferredCategories.push(DEMO_CATEGORIES[Math.floor(rnd() * DEMO_CATEGORIES.length)]);
    }
    const pair = () => `0${Math.floor(rnd() * 90 + 10)}`.slice(-2);
    const phone = `06 ${pair()} ${pair()} ${pair()} ${pair()}`;
    volunteers.push({
      id: `v${i}`,
      firstName,
      lastName,
      fullName: `${firstName} ${lastName}`,
      initials: firstName[0] + lastName[0],
      phone,
      availability,
      preferredCategories,
    });
  }

  // Bénévole de démonstration (« moi ») : disponible partout, demande Bar + Accueil.
  const me = volunteers[0];
  me.preferredCategories = ['BAR', 'WELCOME'];
  FESTIVAL_DAYS.forEach((day) =>
    DAY_PARTS.forEach((part) => me.availability.add(availabilityKey(day.id, part.code))),
  );
  // Référent de démonstration.
  volunteers[1].preferredCategories = ['BAR'];
  // Bénévoles inscrits mais jamais affectés (« oubliés »).
  NEVER_ASSIGNED_INDEXES.forEach((i) => {
    volunteers[i].neverAssigned = true;
  });

  const assignments: Assignment[] = [];
  const busy: Record<string, boolean> = {};
  const dailyHours: Record<string, number> = {};
  const totalHours: Record<string, number> = {};
  let seq = 1;
  let slotIndex = 0;

  positions.forEach((position) => {
    FESTIVAL_DAYS.forEach((day) => {
      position.needs
        .filter((need) => need.dayId === day.id)
        .forEach((need) => {
          slotIndex += 1;
          let target = need.idealStaff;
          if (slotIndex % 7 === 0) target = Math.max(1, need.minStaff - 1);
          else if (slotIndex % 5 === 0) target = need.minStaff;
          else if (slotIndex % 3 === 0) target = Math.max(need.minStaff, need.idealStaff - 1);

          const hours = dayPartHours(need.dayPartCode);
          const pool = volunteers
            .filter(
              (v) =>
                !v.neverAssigned &&
                !busy[`${v.id}|${day.id}|${need.dayPartCode}`] &&
                (dailyHours[`${v.id}|${day.id}`] ?? 0) + hours <= 8,
            )
            .sort((a, b) => score(b) - score(a));

          function score(v: Volunteer): number {
            const available = v.availability.has(availabilityKey(day.id, need.dayPartCode)) ? 100 : 0;
            const wanted = v.preferredCategories.includes(position.category) ? 40 : 0;
            return available + wanted - (totalHours[v.id] ?? 0) * 3;
          }

          pool.slice(0, target).forEach((v) => {
            const status = statusFromRoll(rnd());
            assignments.push({
              id: `a${seq}`,
              volunteerId: v.id,
              positionId: position.id,
              dayId: day.id,
              dayPartCode: need.dayPartCode,
              status,
              source: 'SOLVER',
              locked: false,
              pending: null,
            });
            seq += 1;
            if (status !== 'DECLINED') {
              busy[`${v.id}|${day.id}|${need.dayPartCode}`] = true;
              dailyHours[`${v.id}|${day.id}`] = (dailyHours[`${v.id}|${day.id}`] ?? 0) + hours;
              totalHours[v.id] = (totalHours[v.id] ?? 0) + hours;
            }
          });
        });
    });
  });

  // « Moi » : 1 créneau confirmé puis des propositions à confirmer.
  assignments
    .filter((a) => a.volunteerId === me.id)
    .forEach((a, i) => {
      a.status = i === 0 ? 'CONFIRMED' : 'PROPOSED';
    });

  // Deux surcharges volontaires : plus de 8 h sur le vendredi.
  OVERLOADED_INDEXES.forEach((index) => {
    const volunteer = volunteers[index];
    const dayId = 'ven';
    const taken = assignments
      .filter((a) => a.volunteerId === volunteer.id && a.dayId === dayId)
      .map((a) => a.dayPartCode);
    const freeCode = ['A', 'S', 'N', 'M'].find((code) => !taken.includes(code));
    if (!freeCode) return;
    const position = positions.find((p) =>
      p.needs.some((n) => n.dayId === dayId && n.dayPartCode === freeCode),
    );
    if (!position) return;
    assignments.push({
      id: `a${seq}`,
      volunteerId: volunteer.id,
      positionId: position.id,
      dayId,
      dayPartCode: freeCode,
      status: 'CONFIRMED',
      source: 'MANUAL',
      locked: false,
      pending: null,
    });
    seq += 1;
  });

  // Modifications non encore publiées.
  assignments.forEach((a, i) => {
    if (i % 29 === 7) a.pending = 'ADD';
  });

  const removed = [
    { volunteerName: 'Sarah Prévost', positionName: 'Parking', zone: 'Nord', dayShortLabel: 'VEN 17', dayPartLabel: '17–22' },
    { volunteerName: 'Karim Benali', positionName: 'Propreté', zone: 'Site', dayShortLabel: 'SAM 18', dayPartLabel: '12–17' },
  ];

  return { positions, volunteers, assignments, removed, nextAssignmentSeq: seq };
}