import { PhaseDeadlines, PhaseInfo, PhaseName, PHASE_INFO } from '../models/project-phase.model';
import { addDays, normalizeDateInput } from './date-utils';

const DAY_MS = 24 * 60 * 60 * 1000;

const DEFAULT_PHASE_RATIOS: Record<PhaseName, number> = {
  modeling: 0.3,
  softDecor: 0.25,
  rendering: 0.3,
  postProcessing: 0.15
};

export function generatePhaseDeadlines(
  startDate: Date,
  endDate?: Date,
  ratios: Record<PhaseName, number> = DEFAULT_PHASE_RATIOS
): PhaseDeadlines {
  const safeStart = new Date(startDate);
  const safeEnd = endDate ? new Date(endDate) : addDays(safeStart, 30);

  if (isNaN(safeEnd.getTime()) || safeEnd <= safeStart) {
    safeEnd.setTime(safeStart.getTime() + 30 * DAY_MS);
  }

  const totalDays = Math.max(4, Math.ceil((safeEnd.getTime() - safeStart.getTime()) / DAY_MS));
  const durations = calculatePhaseDurations(totalDays, ratios);

  const deadlines: PhaseDeadlines = {};
  let cursor = new Date(safeStart);

  (Object.keys(durations) as PhaseName[]).forEach((phase, index) => {
    const days = Math.max(1, durations[phase]);
    const deadline = addDays(cursor, days);

    deadlines[phase] = {
      startDate: cursor.toISOString(),
      deadline: deadline.toISOString(),
      estimatedDays: days,
      status: index === 0 ? 'in_progress' : 'not_started',
      priority: index === 0 ? 'high' : 'medium'
    };

    cursor = new Date(deadline.getTime());
  });

  return deadlines;
}

export function ensurePhaseDeadlines(
  existing: PhaseDeadlines | undefined,
  startDate: Date,
  endDate?: Date
): PhaseDeadlines {
  if (existing) {
    return existing;
  }
  return generatePhaseDeadlines(startDate, endDate);
}

export function mapDeliveryTypeToPhase(deliveryType: string): PhaseName | null {
  const map: Record<string, PhaseName> = {
    white_model: 'modeling',
    soft_decor: 'softDecor',
    rendering: 'rendering',
    post_process: 'postProcessing'
  };
  return map[deliveryType] || null;
}

export function getNextPhaseName(current: PhaseName): PhaseName | null {
  const order: PhaseName[] = ['modeling', 'softDecor', 'rendering', 'postProcessing'];
  const index = order.indexOf(current);
  if (index === -1 || index === order.length - 1) {
    return null;
  }
  return order[index + 1];
}

export function updatePhaseOnSubmission(
  deadlines: PhaseDeadlines,
  phase: PhaseName,
  submittedAt: Date
): void {
  const info = ensurePhaseInfo(deadlines, phase);
  const iso = submittedAt.toISOString();

  if (!info.startDate) {
    info.startDate = iso;
  }
  if (!(info as any).firstUploadAt) {
    (info as any).firstUploadAt = iso;
  }
  (info as any).lastSubmissionAt = iso;

  if (!info.deadline) {
    const days = info.estimatedDays || getDefaultPhaseDays(phase);
    const start = normalizeDateInput(info.startDate, submittedAt);
    info.deadline = addDays(start, days).toISOString();
    info.estimatedDays = days;
  }

  if (info.status !== 'completed') {
    info.status = 'in_progress';
  }

  scheduleNextPhase(deadlines, phase, submittedAt);
}

export function markPhaseStatus(
  deadlines: PhaseDeadlines,
  phase: PhaseName,
  status: 'completed' | 'delayed' | 'in_progress',
  timestamp: Date
): void {
  const info = ensurePhaseInfo(deadlines, phase);
  info.status = status;
  if (status === 'completed') {
    info.completedAt = timestamp.toISOString();
  } else if (info.completedAt) {
    delete info.completedAt;
  }
}

export function scheduleNextPhase(
  deadlines: PhaseDeadlines,
  currentPhase: PhaseName,
  anchorDate: Date
): void {
  const nextPhase = getNextPhaseName(currentPhase);
  if (!nextPhase) {
    return;
  }

  const nextInfo = ensurePhaseInfo(deadlines, nextPhase);
  if (!nextInfo.startDate) {
    nextInfo.startDate = anchorDate.toISOString();
  }

  if (!nextInfo.deadline) {
    const days = nextInfo.estimatedDays || getDefaultPhaseDays(nextPhase);
    const start = normalizeDateInput(nextInfo.startDate, anchorDate);
    nextInfo.deadline = addDays(start, days).toISOString();
    nextInfo.estimatedDays = days;
  }

  if (!nextInfo.status || nextInfo.status === 'not_started') {
    nextInfo.status = 'not_started';
  }
}

function ensurePhaseInfo(deadlines: PhaseDeadlines, phase: PhaseName): PhaseInfo {
  if (!deadlines[phase]) {
    const start = new Date();
    const defaultDays = getDefaultPhaseDays(phase);
    deadlines[phase] = {
      startDate: start.toISOString(),
      deadline: addDays(start, defaultDays).toISOString(),
      estimatedDays: defaultDays,
      status: 'not_started',
      priority: 'medium'
    };
  }
  return deadlines[phase]!;
}

function calculatePhaseDurations(
  totalDays: number,
  ratios: Record<PhaseName, number>
): Record<PhaseName, number> {
  const result: Record<PhaseName, number> = {
    modeling: 1,
    softDecor: 1,
    rendering: 1,
    postProcessing: 1
  };

  let allocated = 0;
  (Object.keys(result) as PhaseName[]).forEach((phase) => {
    const ratio = ratios[phase] ?? 0.25;
    const days = Math.max(1, Math.round(totalDays * ratio));
    result[phase] = days;
    allocated += days;
  });

  const diff = totalDays - allocated;
  if (diff !== 0) {
    result.postProcessing = Math.max(1, result.postProcessing + diff);
  }

  return result;
}

function getDefaultPhaseDays(phase: PhaseName): number {
  const meta = PHASE_INFO[phase];
  if (!meta) {
    return 3;
  }
  return Math.max(1, meta.defaultDays || 3);
}