"use client";

import { useMemo, useState } from "react";

export type SortDirection = "asc" | "desc";

export interface ViewFilter {
  field: string;
  operator: "eq" | "neq" | "contains" | "gt" | "lt" | "in" | "isEmpty" | "isNotEmpty";
  value: unknown;
}

export interface ViewSort {
  field: string;
  direction: SortDirection;
}

export interface ViewConfig {
  filters: ViewFilter[];
  sorts: ViewSort[];
  groupBy: string | null;
}

export interface ViewObject {
  id: string;
  type: string;
  title: string;
  status: string | null;
  icon: string | null;
  sortOrder: number;
  parentId: string | null;
  createdAt: string;
  updatedAt: string;
  assignees?: { user: { id: string; name: string | null; avatarUrl: string | null } }[];
  propertyValues?: { propertyDefinition: { id: string; name: string; fieldType: string }; value: unknown }[];
}

const MOCK_OBJECTS: ViewObject[] = [
  { id: "1", type: "task", title: "Design landing page mockups", status: "in_progress", icon: null, sortOrder: 0, parentId: null, createdAt: "2025-03-20", updatedAt: "2025-03-25", assignees: [{ user: { id: "u1", name: "Alice", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "High" }, { propertyDefinition: { id: "p2", name: "Due Date", fieldType: "date" }, value: "2025-04-01" }] },
  { id: "2", type: "task", title: "Implement authentication flow", status: "open", icon: null, sortOrder: 1, parentId: null, createdAt: "2025-03-21", updatedAt: "2025-03-24", assignees: [{ user: { id: "u2", name: "Bob", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "High" }] },
  { id: "3", type: "task", title: "Set up CI/CD pipeline", status: "done", icon: null, sortOrder: 2, parentId: null, createdAt: "2025-03-19", updatedAt: "2025-03-23", assignees: [{ user: { id: "u3", name: "Charlie", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "Medium" }] },
  { id: "4", type: "task", title: "Write API documentation", status: "open", icon: null, sortOrder: 3, parentId: null, createdAt: "2025-03-22", updatedAt: "2025-03-25", assignees: [], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "Low" }] },
  { id: "5", type: "task", title: "Database schema review", status: "in_progress", icon: null, sortOrder: 4, parentId: null, createdAt: "2025-03-18", updatedAt: "2025-03-25", assignees: [{ user: { id: "u1", name: "Alice", avatarUrl: null } }, { user: { id: "u2", name: "Bob", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "High" }, { propertyDefinition: { id: "p2", name: "Due Date", fieldType: "date" }, value: "2025-03-28" }] },
  { id: "6", type: "task", title: "User testing session", status: "open", icon: null, sortOrder: 5, parentId: null, createdAt: "2025-03-23", updatedAt: "2025-03-25", assignees: [{ user: { id: "u4", name: "Diana", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "Medium" }, { propertyDefinition: { id: "p2", name: "Due Date", fieldType: "date" }, value: "2025-04-05" }] },
  { id: "7", type: "task", title: "Performance optimization", status: "closed", icon: null, sortOrder: 6, parentId: null, createdAt: "2025-03-15", updatedAt: "2025-03-20", assignees: [{ user: { id: "u3", name: "Charlie", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "Low" }] },
  { id: "8", type: "task", title: "Mobile responsive fixes", status: "in_progress", icon: null, sortOrder: 7, parentId: null, createdAt: "2025-03-24", updatedAt: "2025-03-25", assignees: [{ user: { id: "u2", name: "Bob", avatarUrl: null } }], propertyValues: [{ propertyDefinition: { id: "p1", name: "Priority", fieldType: "select" }, value: "High" }] },
];

function applyFilters(objects: ViewObject[], filters: ViewFilter[]): ViewObject[] {
  return objects.filter((obj) =>
    filters.every((f) => {
      const val = f.field === "status" ? obj.status : f.field === "title" ? obj.title : null;
      if (f.operator === "eq") return val === f.value;
      if (f.operator === "neq") return val !== f.value;
      if (f.operator === "contains" && typeof val === "string" && typeof f.value === "string")
        return val.toLowerCase().includes(f.value.toLowerCase());
      if (f.operator === "isEmpty") return !val;
      if (f.operator === "isNotEmpty") return !!val;
      return true;
    }),
  );
}

function getField(obj: ViewObject, field: string): unknown {
  return (obj as unknown as Record<string, unknown>)[field];
}

function applySorts(objects: ViewObject[], sorts: ViewSort[]): ViewObject[] {
  if (sorts.length === 0) return objects;
  return [...objects].sort((a, b) => {
    for (const s of sorts) {
      const aVal = getField(a, s.field) ?? "";
      const bVal = getField(b, s.field) ?? "";
      const cmp = String(aVal).localeCompare(String(bVal));
      if (cmp !== 0) return s.direction === "asc" ? cmp : -cmp;
    }
    return 0;
  });
}

function applyGroupBy(objects: ViewObject[], groupBy: string | null): Record<string, ViewObject[]> {
  if (!groupBy) return { "All Items": objects };
  const groups: Record<string, ViewObject[]> = {};
  for (const obj of objects) {
    const key = String(getField(obj, groupBy) ?? "No Value");
    if (!groups[key]) groups[key] = [];
    groups[key].push(obj);
  }
  return groups;
}

export function useViewData(config: ViewConfig) {
  const [objects] = useState<ViewObject[]>(MOCK_OBJECTS);

  const processed = useMemo(() => {
    let result = applyFilters(objects, config.filters);
    result = applySorts(result, config.sorts);
    const grouped = applyGroupBy(result, config.groupBy);
    return { items: result, grouped };
  }, [objects, config]);

  return {
    items: processed.items,
    grouped: processed.grouped,
    isLoading: false,
    total: processed.items.length,
  };
}