// Portable classroom serialization for the frozen bundle.
//
// Mirrors the interactive-ZIP export flow (`lib/export/use-export-classroom.ts`
// + `classroom-zip-utils.ts`) but is pure and server-safe: the browser export
// reads bytes from IndexedDB at call time, while the packager receives bytes
// through injected resolvers. The manifest shape is identical, so the L3
// player can reuse the existing import machinery
// (`rewriteAudioRefsToIds` / manifest → document) unchanged.

import type { Action, DiscussionAction, SpeechAction } from '@/lib/types/action';
import type { GeneratedAgentConfig, Scene, Stage } from '@/lib/types/stage';
import type {
  ClassroomManifest,
  ManifestAction,
  ManifestAgent,
  ManifestScene,
  ManifestStage,
  MediaIndexEntry,
} from '@/lib/export/classroom-zip-types';
import {
  manifestAgentFromConfig,
  CLASSROOM_ZIP_FORMAT_VERSION,
} from '@/lib/export/classroom-zip-types';

export interface ManifestBuildOptions {
  appVersion: string;
  /** audioId → ZIP path (`audio/<id>.<ext>`); speech actions are rewritten to `audioRef`. */
  audioIdToPath: Map<string, string>;
  agentConfigs: GeneratedAgentConfig[];
  exportedAt?: string;
}

export function serializeActions(
  actions: Action[],
  audioIdToPath: Map<string, string>,
  agentIdToIndex: Map<string, number>,
): ManifestAction[] {
  return actions.map((action) => {
    if (action.type === 'speech') {
      const speech = action as SpeechAction;
      const { audioId, audioUrl, ...rest } = speech;
      const audioRef = audioId ? audioIdToPath.get(audioId) : undefined;
      return {
        ...rest,
        ...(audioRef ? { audioRef } : {}),
        // A frozen bundle must play its embedded bytes. Keep a remote URL only
        // for legacy URL-only speech that could not be mapped to bundle audio.
        ...(!audioRef && audioUrl ? { audioUrl } : {}),
      } as ManifestAction;
    }
    if (action.type === 'discussion') {
      const discussion = action as DiscussionAction;
      const { agentId, ...rest } = discussion;
      const agentIndex = agentId ? agentIdToIndex.get(agentId) : undefined;
      return {
        ...rest,
        ...(agentIndex !== undefined ? { agentIndex } : agentId ? { agentId } : {}),
      } as ManifestAction;
    }
    return action as ManifestAction;
  });
}

export interface SerializedScene {
  scene: ManifestScene;
  /** MediaIndexEntry additions for this scene's audio/media, keyed by ZIP path. */
}

/** Serialize one scene into its portable manifest shape (interactive HTML assumed pre-inlined). */
export function serializeScene(
  scene: Scene,
  audioIdToPath: Map<string, string>,
  agentIdToIndex: Map<string, number>,
): ManifestScene {
  return {
    type: scene.type,
    title: scene.title,
    order: scene.order,
    content: scene.content,
    actions: scene.actions
      ? serializeActions(scene.actions, audioIdToPath, agentIdToIndex)
      : undefined,
    whiteboards: scene.whiteboards,
    ...(scene.multiAgent?.enabled
      ? {
          multiAgent: {
            enabled: true,
            agentIndices: (scene.multiAgent.agentIds ?? [])
              .map((id) => agentIdToIndex.get(id))
              .filter((index): index is number => index !== undefined),
            directorPrompt: scene.multiAgent.directorPrompt,
          },
        }
      : {}),
  };
}

export function serializeStage(stage: Stage): ManifestStage {
  return {
    name: stage.name,
    description: stage.description,
    language: stage.languageDirective,
    style: stage.style,
    whiteboard: stage.whiteboard,
    videoManifest: stage.videoManifest,
    interactiveMode: stage.interactiveMode,
    taskEngineMode: stage.taskEngineMode,
    createdAt: stage.createdAt,
    updatedAt: stage.updatedAt,
  };
}

/**
 * Build the portable classroom manifest.
 *
 * `scenes` must already carry inlined interactive HTML and prepared PBL
 * scenes (the packager's responsibility); `mediaIndex` is supplied by the
 * caller, which owns byte collection.
 */
export function buildManifest(
  stage: Stage,
  scenes: Scene[],
  options: ManifestBuildOptions,
  mediaIndex: Record<string, MediaIndexEntry>,
): ClassroomManifest {
  const agentIdToIndex = new Map<string, number>();
  options.agentConfigs.forEach((agent, index) => agentIdToIndex.set(agent.id, index));

  return {
    formatVersion: CLASSROOM_ZIP_FORMAT_VERSION,
    exportedAt: options.exportedAt ?? new Date().toISOString(),
    appVersion: options.appVersion,
    stage: serializeStage(stage),
    agents: options.agentConfigs.map(manifestAgentFromConfig) satisfies ManifestAgent[],
    scenes: scenes.map((scene) => serializeScene(scene, options.audioIdToPath, agentIdToIndex)),
    mediaIndex,
  };
}