import { SCORM12, SCORM2004 } from './data-model.js';
import { ScormWrapper } from './api-adapter.js';
import type { Scorm2004Mode, Scorm2004Credit, Scorm2004Entry, ScormVersion } from './types.js';
import { ScoreState } from './score-state.svelte.js';
import { CompletionState } from './completion-state.svelte.js';
import { PersistentStore } from './persistent-store.svelte.js';
import { StandardStorageEngine, ChunkedStorageEngine } from './storage/index.js';
import type { StorageMode } from './storage/index.js';

export interface InitializeOptions {
	courseId: string;
	minScore: number;
	maxScore: number;
	storageMode?: StorageMode;
}

class StudentState {
	#id = $state('');
	#name = $state('');

	get id(): string {
		return this.#id;
	}

	get name(): string {
		return this.#name;
	}

	load(wrapper: ScormWrapper): void {
		const isV2004 = wrapper.version === '2004';
		this.#id = wrapper.getValue(isV2004 ? SCORM2004.LEARNER_ID : SCORM12.CORE_STUDENT_ID);
		this.#name = wrapper.getValue(isV2004 ? SCORM2004.LEARNER_NAME : SCORM12.CORE_STUDENT_NAME);
	}
}

class SessionState {
	#mode = $state<Scorm2004Mode>('normal');
	#credit = $state<Scorm2004Credit>('credit');
	#entry = $state<Scorm2004Entry | 'ab-initio'>('ab-initio');

	get mode(): Scorm2004Mode {
		return this.#mode;
	}

	get credit(): Scorm2004Credit {
		return this.#credit;
	}

	get entry(): Scorm2004Entry | 'ab-initio' {
		return this.#entry;
	}

	load(wrapper: ScormWrapper): void {
		const isV2004 = wrapper.version === '2004';
		this.#mode = wrapper.getValue(
			isV2004 ? SCORM2004.MODE : SCORM12.CORE_LESSON_MODE
		) as Scorm2004Mode;
		this.#credit = wrapper.getValue(
			isV2004 ? SCORM2004.CREDIT : SCORM12.CORE_CREDIT
		) as Scorm2004Credit;
		this.#entry = wrapper.getValue(isV2004 ? SCORM2004.ENTRY : SCORM12.CORE_ENTRY) as
			| Scorm2004Entry
			| 'ab-initio';
	}
}

export class ScormState {
	#wrapper = new ScormWrapper();
	#sessionStart = 0;
	#location = $state('');

	readonly student: StudentState;
	readonly session: SessionState;
	readonly score: ScoreState;
	readonly completion: CompletionState;
	readonly store: PersistentStore;

	isConnected = $state(false);
	isInitialized = $state(false);
	version = $state<ScormVersion>();
	mode = $state<'lms' | 'dev'>('dev');

	constructor() {
		this.student = new StudentState();
		this.session = new SessionState();
		this.score = new ScoreState(this.#wrapper);
		this.completion = new CompletionState(this.#wrapper);
		this.store = new PersistentStore();
	}

	get location(): string {
		return this.#location;
	}

	set location(value: string) {
		this.#location = value;
		const element =
			this.#wrapper.version === '2004' ? SCORM2004.LOCATION : SCORM12.CORE_LESSON_LOCATION;
		this.#wrapper.setValue(element, value);
		this.#wrapper.commit();
	}

	initialize({
		courseId,
		minScore,
		maxScore,
		storageMode = 'standard'
	}: InitializeOptions): boolean {
		this.mode = this.#wrapper.connect(courseId);
		this.isConnected = true;
		const result = this.#wrapper.initialize();
		this.isInitialized = result;
		this.version = this.#wrapper.version;
		this.student.load(this.#wrapper);
		this.session.load(this.#wrapper);
		this.score.load(this.#wrapper);
		this.score._setRange(minScore, maxScore);
		this.completion.load(this.#wrapper);
		const isV2004 = this.#wrapper.version === '2004';
		this.#location = this.#wrapper.getValue(
			isV2004 ? SCORM2004.LOCATION : SCORM12.CORE_LESSON_LOCATION
		);
		this.#sessionStart = Date.now();
		const engine =
			storageMode === 'chunked' ? new ChunkedStorageEngine() : new StandardStorageEngine();
		this.store._setEngine(engine, this.#wrapper);
		this.store._load(this.#wrapper);
		return result;
	}

	get sessionStartTime(): number {
		return this.isInitialized ? this.#sessionStart : 0;
	}

	get sessionElapsedMs(): number {
		return this.isInitialized ? Date.now() - this.#sessionStart : 0;
	}

	commit(): void {
		this.#wrapper.commit();
	}

	terminate(): void {
		if (!this.isInitialized) return;
		this.isInitialized = false;
		const elapsed = Date.now() - this.#sessionStart;
		const sessionTime = this.#wrapper.formatSessionTime(elapsed);
		const timeElement =
			this.#wrapper.version === '2004' ? SCORM2004.SESSION_TIME : SCORM12.CORE_SESSION_TIME;
		this.#wrapper.setValue(timeElement, sessionTime);
		this.#wrapper.commit();
		this.#wrapper.terminate();
	}
}

export const scormState = new ScormState();