import http from './client'
import type { BatchDeleteResult, PageQuery, PageResult } from './types'

/** Mirrors `app.schemas.template_field_library.TemplateFieldLibraryRead`. */
export interface TemplateFieldLibrary {
  id: number
  /** Display name, numbering included — e.g. `1. Introduction`. */
  name: string
  /** Heading depth: 1 for `1.`, 2 for `1.1`. A rendering hint, not a parent. */
  level: number
  /** Points. Fractional, because 五号 = 10.5pt. */
  font_size: number
  /** Canonical RGB as `#RRGGBB`. */
  font_color: string
  created_at: string
  updated_at: string
}

/** Body for creating or updating a library field. */
export interface TemplateFieldLibraryPayload {
  name: string
  level: number
  font_size: number
  font_color: string
}

export interface TemplateFieldLibraryQuery extends PageQuery {
  level?: number | null
}

/** The API caps `page_size` at 500; 200 keeps responses modest while looping. */
const LIBRARY_PAGE_SIZE = 200

export async function listTemplateFieldLibrary(
  query: TemplateFieldLibraryQuery = {},
): Promise<PageResult<TemplateFieldLibrary>> {
  // Drop empty filters so the URL stays clean and the backend sees "no filter"
  // rather than `keyword=`.
  const params: Record<string, unknown> = {}
  if (query.keyword) params.keyword = query.keyword
  if (query.level != null) params.level = query.level
  if (query.page) params.page = query.page
  if (query.page_size) params.page_size = query.page_size

  const { data } = await http.get<PageResult<TemplateFieldLibrary>>(
    '/template-field-library',
    { params },
  )
  return data
}

/**
 * Fetch the entire library, following pagination.
 *
 * The template form needs every field, not one page, so that a field placed
 * deep in the library can still be shown by name in an existing selection.
 */
export async function fetchAllTemplateFieldLibrary(keyword?: string): Promise<TemplateFieldLibrary[]> {
  const all: TemplateFieldLibrary[] = []
  let page = 1

  for (;;) {
    const result = await listTemplateFieldLibrary({
      keyword,
      page,
      page_size: LIBRARY_PAGE_SIZE,
    })
    all.push(...result.items)
    if (page >= result.pages || result.items.length === 0) {
      return all
    }
    page += 1
  }
}

export async function createTemplateFieldLibrary(
  payload: TemplateFieldLibraryPayload,
): Promise<TemplateFieldLibrary> {
  const { data } = await http.post<TemplateFieldLibrary>('/template-field-library', payload)
  return data
}

export async function updateTemplateFieldLibrary(
  id: number,
  payload: Partial<TemplateFieldLibraryPayload>,
): Promise<TemplateFieldLibrary> {
  const { data } = await http.patch<TemplateFieldLibrary>(`/template-field-library/${id}`, payload)
  return data
}

export async function deleteTemplateFieldLibrary(id: number): Promise<void> {
  await http.delete(`/template-field-library/${id}`)
}

export async function batchDeleteTemplateFieldLibrary(
  ids: number[],
): Promise<BatchDeleteResult> {
  const { data } = await http.post<BatchDeleteResult>('/template-field-library/batch-delete', {
    ids,
  })
  return data
}