/**
 * API client for the reader module — reading settings, chapters, and progress.
 */

import type {
  ChapterDetail,
  ChapterSummary,
  ReadingProgress,
  ReadingSettings,
} from "../types/reader";

const API_BASE = "/api";

/**
 * Fetch the current user's reading settings.
 * Auto-creates defaults on the server if none exist.
 */
export async function getReadingSettings(): Promise<ReadingSettings> {
  const response = await fetch(`${API_BASE}/reader/settings/`);
  if (!response.ok) {
    throw new Error(
      `Failed to fetch reading settings: ${response.status} ${response.statusText}`
    );
  }
  return response.json() as Promise<ReadingSettings>;
}

/**
 * Update (full or partial) the user's reading settings.
 */
export async function updateReadingSettings(
  settings: Partial<ReadingSettings>
): Promise<ReadingSettings> {
  const method = settings.theme !== undefined ? "PUT" : "PATCH";
  const response = await fetch(`${API_BASE}/reader/settings/`, {
    method,
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(settings),
  });
  if (!response.ok) {
    throw new Error(
      `Failed to update reading settings: ${response.status} ${response.statusText}`
    );
  }
  return response.json() as Promise<ReadingSettings>;
}

/**
 * Fetch the table of contents (chapter list) for a book.
 */
export async function getChapters(bookId: number): Promise<ChapterSummary[]> {
  const response = await fetch(`${API_BASE}/books/${bookId}/chapters/`);
  if (!response.ok) {
    throw new Error(
      `Failed to fetch chapters: ${response.status} ${response.statusText}`
    );
  }
  return response.json() as Promise<ChapterSummary[]>;
}

/**
 * Fetch a specific chapter with full content for reading.
 */
export async function getChapterContent(
  bookId: number,
  chapterNumber: number
): Promise<ChapterDetail> {
  const response = await fetch(
    `${API_BASE}/books/${bookId}/chapters/${chapterNumber}/`
  );
  if (!response.ok) {
    throw new Error(
      `Failed to fetch chapter ${chapterNumber}: ${response.status} ${response.statusText}`
    );
  }
  return response.json() as Promise<ChapterDetail>;
}

/**
 * Fetch reading progress for a book.
 */
export async function getReadingProgress(
  bookId: number
): Promise<ReadingProgress> {
  const response = await fetch(`${API_BASE}/books/${bookId}/progress/`);
  if (!response.ok) {
    throw new Error(
      `Failed to fetch reading progress: ${response.status} ${response.statusText}`
    );
  }
  return response.json() as Promise<ReadingProgress>;
}

/**
 * Update reading progress for a book.
 */
export async function updateReadingProgress(
  bookId: number,
  progress: Partial<ReadingProgress>
): Promise<ReadingProgress> {
  const response = await fetch(`${API_BASE}/books/${bookId}/progress/`, {
    method: "PUT",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(progress),
  });
  if (!response.ok) {
    throw new Error(
      `Failed to update reading progress: ${response.status} ${response.statusText}`
    );
  }
  return response.json() as Promise<ReadingProgress>;
}