import React from 'react';
import type { Session } from '@opencode-ai/sdk/v2';
import type { SessionSummaryMeta } from './types';

const formatDateLabel = (value: string | number) => {
  const targetDate = new Date(value);
  const today = new Date();
  const isSameDay = (a: Date, b: Date) =>
    a.getFullYear() === b.getFullYear() &&
    a.getMonth() === b.getMonth() &&
    a.getDate() === b.getDate();

  const yesterday = new Date(today);
  yesterday.setDate(today.getDate() - 1);

  if (isSameDay(targetDate, today)) {
    return 'Today';
  }
  if (isSameDay(targetDate, yesterday)) {
    return 'Yesterday';
  }
  const formatted = targetDate.toLocaleDateString('en-US', {
    month: 'short',
    day: 'numeric',
    year: 'numeric',
  });
  return formatted.replace(',', '');
};

export const formatSessionDateLabel = (updatedMs: number): string => {
  const today = new Date();
  const updatedDate = new Date(updatedMs);
  const isSameDay = (a: Date, b: Date) =>
    a.getFullYear() === b.getFullYear() &&
    a.getMonth() === b.getMonth() &&
    a.getDate() === b.getDate();

  if (isSameDay(updatedDate, today)) {
    const diff = Date.now() - updatedMs;
    if (diff < 60_000) return 'Just now';
    if (diff < 3_600_000) return `${Math.floor(diff / 60_000)}min ago`;
    return `${Math.floor(diff / 3_600_000)}h ago`;
  }

  return formatDateLabel(updatedMs);
};

export const formatSessionCompactDateLabel = (updatedMs: number): string => {
  const diff = Math.max(0, Date.now() - updatedMs);

  const minute = 60_000;
  const hour = 60 * minute;
  const day = 24 * hour;
  const week = 7 * day;
  const month = 30 * day;
  const year = 365 * day;

  if (diff < hour) {
    return `${Math.max(1, Math.floor(diff / minute))}m`;
  }
  if (diff < day) {
    return `${Math.floor(diff / hour)}h`;
  }
  if (diff < week) {
    return `${Math.floor(diff / day)}d`;
  }
  if (diff < 5 * week) {
    return `${Math.floor(diff / week)}w`;
  }
  if (diff < year) {
    return `${Math.floor(diff / month)}mo`;
  }
  return `${Math.floor(diff / year)}y`;
};

export const normalizePath = (value?: string | null) => {
  if (!value) {
    return null;
  }
  const normalized = value.replace(/\\/g, '/').replace(/\/+$/, '');
  return normalized.length === 0 ? '/' : normalized;
};

export const normalizeForBranchComparison = (value: string): string => {
  return value
    .toLowerCase()
    .replace(/^opencode[/-]?/i, '')
    .replace(/[-_]/g, '')
    .trim();
};

export const isBranchDifferentFromLabel = (branch: string | null, label: string): boolean => {
  if (!branch) return false;
  return normalizeForBranchComparison(branch) !== normalizeForBranchComparison(label);
};

const toFiniteNumber = (value: unknown): number | undefined => {
  if (typeof value === 'number' && Number.isFinite(value)) {
    return value;
  }
  if (typeof value === 'string' && value.trim().length > 0) {
    const parsed = Number(value);
    if (Number.isFinite(parsed)) {
      return parsed;
    }
  }
  return undefined;
};

const getSessionCreatedAt = (session: Session): number => {
  return toFiniteNumber(session.time?.created) ?? 0;
};

const getSessionUpdatedAt = (session: Session): number => {
  return toFiniteNumber(session.time?.updated) ?? toFiniteNumber(session.time?.created) ?? 0;
};

export const compareSessionsByPinnedAndTime = (
  a: Session,
  b: Session,
  pinnedSessionIds: Set<string>,
): number => {
  const aPinned = pinnedSessionIds.has(a.id);
  const bPinned = pinnedSessionIds.has(b.id);
  if (aPinned !== bPinned) {
    return aPinned ? -1 : 1;
  }

  if (aPinned && bPinned) {
    return getSessionCreatedAt(b) - getSessionCreatedAt(a);
  }

  return getSessionUpdatedAt(b) - getSessionUpdatedAt(a);
};

export const compareSessionsByPinnedAndCreated = (
  a: Session,
  b: Session,
  pinnedSessionIds: Set<string>,
): number => {
  const aPinned = pinnedSessionIds.has(a.id);
  const bPinned = pinnedSessionIds.has(b.id);
  if (aPinned !== bPinned) {
    return aPinned ? -1 : 1;
  }

  return getSessionCreatedAt(b) - getSessionCreatedAt(a);
};

export const dedupeSessionsById = (sessions: Session[]): Session[] => {
  const byId = new Map<string, Session>();
  sessions.forEach((session) => {
    byId.set(session.id, session);
  });
  return Array.from(byId.values());
};

export const getArchivedScopeKey = (projectRoot: string): string => `__archived__:${projectRoot}`;

export const resolveArchivedFolderName = (session: Session, projectRoot: string | null): string => {
  const sessionDirectory = normalizePath((session as Session & { directory?: string | null }).directory ?? null);
  const projectWorktree = normalizePath((session as Session & { project?: { worktree?: string | null } | null }).project?.worktree ?? null);
  const resolved = sessionDirectory ?? projectWorktree;
  if (!resolved) {
    return 'unassigned';
  }
  if (projectRoot && resolved === projectRoot) {
    return 'project root';
  }
  const source = projectRoot && resolved.startsWith(`${projectRoot}/`)
    ? resolved.slice(projectRoot.length + 1)
    : resolved;
  const segments = source.split('/').filter(Boolean);
  return segments[segments.length - 1] ?? 'unassigned';
};

export const isSessionRelatedToProject = (
  session: Session,
  projectRoot: string,
  validDirectories?: Set<string>,
): boolean => {
  const sessionDirectory = normalizePath((session as Session & { directory?: string | null }).directory ?? null);
  const projectWorktree = normalizePath((session as Session & { project?: { worktree?: string | null } | null }).project?.worktree ?? null);

  if (projectWorktree && (projectWorktree === projectRoot || projectWorktree.startsWith(`${projectRoot}/`))) {
    return true;
  }

  if (!sessionDirectory) {
    return false;
  }
  if (validDirectories && validDirectories.has(sessionDirectory)) {
    return true;
  }
  return sessionDirectory === projectRoot || sessionDirectory.startsWith(`${projectRoot}/`);
};

const parseSummaryCount = (value: number | string | null | undefined): number | null => {
  if (typeof value === 'number' && Number.isFinite(value)) {
    return value;
  }
  if (typeof value === 'string') {
    const parsed = Number(value);
    if (Number.isFinite(parsed)) {
      return parsed;
    }
  }
  return null;
};

export const resolveSessionDiffStats = (summary?: SessionSummaryMeta): { additions: number; deletions: number } | null => {
  if (!summary) {
    return null;
  }

  const directAdditions = parseSummaryCount(summary.additions);
  const directDeletions = parseSummaryCount(summary.deletions);
  if (directAdditions !== null || directDeletions !== null) {
    const stats = {
      additions: Math.max(0, directAdditions ?? 0),
      deletions: Math.max(0, directDeletions ?? 0),
    };
    return stats.additions === 0 && stats.deletions === 0 ? null : stats;
  }

  const diffs = Array.isArray(summary.diffs) ? summary.diffs : [];
  if (diffs.length === 0) {
    return null;
  }

  let additions = 0;
  let deletions = 0;
  diffs.forEach((diff) => {
    additions += Math.max(0, parseSummaryCount(diff.additions) ?? 0);
    deletions += Math.max(0, parseSummaryCount(diff.deletions) ?? 0);
  });
  return additions === 0 && deletions === 0 ? null : { additions, deletions };
};

export const formatProjectLabel = (label: string): string => {
  return label
    .replace(/[-_]/g, ' ')
    .replace(/\b\w/g, (char) => char.toUpperCase());
};

export const renderHighlightedText = (text: string, query: string): React.ReactNode => {
  if (!query) {
    return text;
  }

  const loweredText = text.toLowerCase();
  const loweredQuery = query.toLowerCase();
  const queryLength = loweredQuery.length;
  if (queryLength === 0) {
    return text;
  }

  const parts: React.ReactNode[] = [];
  let cursor = 0;
  let matchIndex = loweredText.indexOf(loweredQuery, cursor);

  while (matchIndex !== -1) {
    if (matchIndex > cursor) {
      parts.push(text.slice(cursor, matchIndex));
    }
    const matchText = text.slice(matchIndex, matchIndex + queryLength);
    parts.push(
      <mark
        key={`${matchIndex}-${matchText}`}
        className="bg-primary text-primary-foreground ring-1 ring-primary/90"
      >
        {matchText}
      </mark>,
    );
    cursor = matchIndex + queryLength;
    matchIndex = loweredText.indexOf(loweredQuery, cursor);
  }

  if (cursor < text.length) {
    parts.push(text.slice(cursor));
  }

  return parts.length > 0 ? parts : text;
};