/**
 * Draft/publish hooks for attribute values.
 *
 * Provider (escort) entity types use a draft layer: auto-save writes drafts,
 * user reviews, then explicitly publishes. Other entity types save directly.
 */

import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { attributeValueKeys, type EntityType, type AttributeValues } from './index';

// API base URL - same as main hooks
const API_BASE = typeof window !== 'undefined'
  ? (window as { __API_BASE__?: string }).__API_BASE__ || '/api'
  : '/api';

// --- Types ---

export interface DraftDiffItem {
  code: string;
  oldValue: unknown;
  draftValue: unknown;
  updatedAt: string;
}

export interface PublishResult {
  publishedCount: number;
}

// --- Query Keys ---

export const draftKeys = {
  all: ['attribute-value-drafts'] as const,
  check: (entityType: EntityType) =>
    [...draftKeys.all, 'check', entityType] as const,
  list: (entityType: EntityType, entityId: string, userId: string) =>
    [...draftKeys.all, 'list', entityType, entityId, userId] as const,
  diff: (entityType: EntityType, entityId: string, userId: string) =>
    [...draftKeys.all, 'diff', entityType, entityId, userId] as const,
  count: (entityType: EntityType, entityId: string, userId: string) =>
    [...draftKeys.all, 'count', entityType, entityId, userId] as const,
};

// --- API Functions (exported for imperative use, e.g. ensureQueryData) ---

export async function fetchDraftCheck(entityType: EntityType): Promise<{ usesDrafts: boolean }> {
  const response = await fetch(
    `${API_BASE}/attribute-value-drafts/check?entityType=${entityType}`
  );
  if (!response.ok) {
    throw new Error(`Failed to check draft support: ${response.statusText}`);
  }
  return response.json();
}

async function fetchDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
): Promise<AttributeValues> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts?${params}`);
  if (!response.ok) {
    throw new Error(`Failed to fetch drafts: ${response.statusText}`);
  }
  return response.json();
}

async function fetchDraftDiff(
  entityType: EntityType,
  entityId: string,
  userId: string,
): Promise<DraftDiffItem[]> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts/diff?${params}`);
  if (!response.ok) {
    throw new Error(`Failed to fetch draft diff: ${response.statusText}`);
  }
  return response.json();
}

async function fetchDraftCount(
  entityType: EntityType,
  entityId: string,
  userId: string,
): Promise<{ count: number }> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts/count?${params}`);
  if (!response.ok) {
    throw new Error(`Failed to fetch draft count: ${response.statusText}`);
  }
  return response.json();
}

export async function setDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
  values: AttributeValues,
): Promise<void> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts?${params}`, {
    method: 'PUT',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(values),
  });
  if (!response.ok) {
    throw new Error(`Failed to save drafts: ${response.statusText}`);
  }
}

async function publishDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
): Promise<PublishResult> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts/publish?${params}`, {
    method: 'POST',
  });
  if (!response.ok) {
    throw new Error(`Failed to publish drafts: ${response.statusText}`);
  }
  return response.json();
}

async function publishSelectedDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
  codes: string[],
): Promise<PublishResult> {
  const response = await fetch(`${API_BASE}/attribute-value-drafts/publish-selected`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ entityType, entityId, userId, codes }),
  });
  if (!response.ok) {
    throw new Error(`Failed to publish selected drafts: ${response.statusText}`);
  }
  return response.json();
}

async function discardAllDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
): Promise<{ discarded: number }> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts?${params}`, {
    method: 'DELETE',
  });
  if (!response.ok) {
    throw new Error(`Failed to discard drafts: ${response.statusText}`);
  }
  return response.json();
}

async function discardOneDraft(
  entityType: EntityType,
  entityId: string,
  userId: string,
  code: string,
): Promise<void> {
  const params = new URLSearchParams({ entityType, entityId, userId });
  const response = await fetch(`${API_BASE}/attribute-value-drafts/${code}?${params}`, {
    method: 'DELETE',
  });
  if (!response.ok) {
    throw new Error(`Failed to discard draft: ${response.statusText}`);
  }
}

// --- Hooks ---

/**
 * Check if an entity type uses the draft/publish workflow.
 * Result is cached with staleTime: Infinity since it's config-level.
 */
export function useCheckDraftSupport(entityType: EntityType) {
  const query = useQuery({
    queryKey: draftKeys.check(entityType),
    queryFn: () => fetchDraftCheck(entityType),
    staleTime: Infinity,
    retry: false,
    enabled: !!entityType,
  });

  return {
    usesDrafts: query.data?.usesDrafts ?? false,
    isLoading: query.isLoading,
    error: query.error,
  };
}

/**
 * Fetch pending draft values as a code→value map.
 * Only enabled when draft mode is active.
 */
export function useDraftValues(
  entityType: EntityType,
  entityId: string,
  userId: string,
  options?: { enabled?: boolean },
) {
  const query = useQuery({
    queryKey: draftKeys.list(entityType, entityId, userId),
    queryFn: () => fetchDrafts(entityType, entityId, userId),
    retry: false,
    enabled: (options?.enabled ?? true) && !!entityType && !!entityId && !!userId,
  });

  return {
    data: query.data ?? {},
    isLoading: query.isLoading,
    error: query.error,
    refetch: query.refetch,
  };
}

/**
 * Fetch draft diff items for the summary panel.
 * Only enabled when draft mode is active.
 */
export function useDraftDiff(
  entityType: EntityType,
  entityId: string,
  userId: string,
  options?: { enabled?: boolean },
) {
  const query = useQuery({
    queryKey: draftKeys.diff(entityType, entityId, userId),
    queryFn: () => fetchDraftDiff(entityType, entityId, userId),
    retry: false,
    enabled: (options?.enabled ?? true) && !!entityType && !!entityId && !!userId,
  });

  return {
    data: query.data ?? [],
    isLoading: query.isLoading,
    error: query.error,
    refetch: query.refetch,
  };
}

/**
 * Fetch count of pending drafts.
 * Only enabled when draft mode is active.
 */
export function useDraftCount(
  entityType: EntityType,
  entityId: string,
  userId: string,
  options?: { enabled?: boolean },
) {
  const query = useQuery({
    queryKey: draftKeys.count(entityType, entityId, userId),
    queryFn: () => fetchDraftCount(entityType, entityId, userId),
    retry: false,
    enabled: (options?.enabled ?? true) && !!entityType && !!entityId && !!userId,
  });

  return {
    count: query.data?.count ?? 0,
    isLoading: query.isLoading,
    error: query.error,
  };
}

/**
 * Mutation to upsert draft values.
 */
export function useSetDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
) {
  const queryClient = useQueryClient();

  const mutation = useMutation({
    mutationFn: (values: AttributeValues) =>
      setDrafts(entityType, entityId, userId, values),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: draftKeys.list(entityType, entityId, userId) });
      queryClient.invalidateQueries({ queryKey: draftKeys.diff(entityType, entityId, userId) });
      queryClient.invalidateQueries({ queryKey: draftKeys.count(entityType, entityId, userId) });
    },
  });

  return {
    mutate: mutation.mutate,
    mutateAsync: mutation.mutateAsync,
    isPending: mutation.isPending,
    error: mutation.error,
  };
}

/**
 * Mutation to publish all drafts.
 */
export function usePublishDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
) {
  const queryClient = useQueryClient();

  const mutation = useMutation({
    mutationFn: () => publishDrafts(entityType, entityId, userId),
    onSuccess: () => {
      // Invalidate drafts (now empty)
      queryClient.invalidateQueries({ queryKey: draftKeys.all });
      // Invalidate live values (now updated)
      queryClient.invalidateQueries({ queryKey: attributeValueKeys.list(entityType, entityId) });
    },
  });

  return {
    mutate: mutation.mutate,
    mutateAsync: mutation.mutateAsync,
    isPending: mutation.isPending,
    error: mutation.error,
  };
}

/**
 * Mutation to publish selected drafts by code.
 */
export function usePublishSelectedDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
) {
  const queryClient = useQueryClient();

  const mutation = useMutation({
    mutationFn: (codes: string[]) =>
      publishSelectedDrafts(entityType, entityId, userId, codes),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: draftKeys.all });
      queryClient.invalidateQueries({ queryKey: attributeValueKeys.list(entityType, entityId) });
    },
  });

  return {
    mutate: mutation.mutate,
    mutateAsync: mutation.mutateAsync,
    isPending: mutation.isPending,
    error: mutation.error,
  };
}

/**
 * Mutation to discard all drafts.
 */
export function useDiscardAllDrafts(
  entityType: EntityType,
  entityId: string,
  userId: string,
) {
  const queryClient = useQueryClient();

  const mutation = useMutation({
    mutationFn: () => discardAllDrafts(entityType, entityId, userId),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: draftKeys.all });
    },
  });

  return {
    mutate: mutation.mutate,
    mutateAsync: mutation.mutateAsync,
    isPending: mutation.isPending,
    error: mutation.error,
  };
}

/**
 * Mutation to discard a single draft.
 */
export function useDiscardOneDraft(
  entityType: EntityType,
  entityId: string,
  userId: string,
) {
  const queryClient = useQueryClient();

  const mutation = useMutation({
    mutationFn: (code: string) =>
      discardOneDraft(entityType, entityId, userId, code),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: draftKeys.all });
    },
  });

  return {
    mutate: mutation.mutate,
    mutateAsync: mutation.mutateAsync,
    isPending: mutation.isPending,
    error: mutation.error,
  };
}