import * as yaml from "js-yaml";
import * as fs from "fs";
import * as path from "path";
import { z } from "zod";

export interface StoryConfig {
  metadata: {
    title: string;
    author: string;
    publication_year: number;
    public_domain_proof_url: string;
    reading_level: string;
  };
  config: {
    chunk_size: number;
    tts_voice_id: string;
    tts_instructions?: string;
    image_style_prompts?: string;
    intro_audio_file: string;
    outro_audio_file: string;
    background_music_file: string;
    export_settings: {
      format?: string;
      resolution: string;
    };
  };
}

const StoryConfigSchema = z.object({
  metadata: z.object({
    title: z.string().min(1),
    author: z.string().min(1),
    publication_year: z.number().int(),
    public_domain_proof_url: z.string().min(1),
    reading_level: z.string().min(1),
  }),
  config: z.object({
    chunk_size: z.number().int().positive(),
    tts_voice_id: z.string().min(1),
    tts_instructions: z.string().optional().default(""),
    image_style_prompts: z.string().optional().default(""),
    intro_audio_file: z.string().min(1),
    outro_audio_file: z.string().min(1),
    background_music_file: z.string().min(1),
    export_settings: z
      .object({
        format: z.string().optional().default("mp4"),
        resolution: z
          .string()
          .regex(/^\d+x\d+$/)
          .default("1024x1024"),
      })
      .default({ format: "mp4", resolution: "1024x1024" }),
  }),
});

export function loadStoryConfig(storyName: string): StoryConfig {
  const configPath = path.join("stories", storyName, "config.yaml");
  if (!fs.existsSync(configPath)) {
    throw new Error(`Configuration file not found for story: ${storyName}`);
  }

  const fileContents = fs.readFileSync(configPath, "utf8");
  const loaded = yaml.load(fileContents);
  const parsed = StoryConfigSchema.parse(loaded);
  return parsed as unknown as StoryConfig;
}