import { findScorm12API, findScorm2004API } from './api-finder.js';
import type { Scorm12API, Scorm2004API, ScormVersion } from './types.js';

const MS_PER_SECOND = 1000;
const SECONDS_PER_HOUR = 3600;
const SECONDS_PER_MINUTE = 60;
const DECIMAL_RADIX = 10;

function padTwo(value: number): string {
	return String(value).padStart(2, '0');
}

function elapsedToComponents(elapsedMs: number): {
	h: number;
	m: number;
	s: number;
} {
	const total = Math.floor(elapsedMs / MS_PER_SECOND);
	const h = Math.floor(total / SECONDS_PER_HOUR);
	const m = Math.floor((total % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE);
	const s = total % SECONDS_PER_MINUTE;
	return { h, m, s };
}

function formatSessionTime12(elapsedMs: number): string {
	const { h, m, s } = elapsedToComponents(elapsedMs);
	return `${padTwo(h)}:${padTwo(m)}:${padTwo(s)}`;
}

function formatSessionTime2004(elapsedMs: number): string {
	const { h, m, s } = elapsedToComponents(elapsedMs);
	return `PT${h}H${m}M${s}S`;
}

export class ScormWrapper {
	#api12: Scorm12API | undefined;
	#api2004: Scorm2004API | undefined;
	#version: ScormVersion | undefined;
	#devStore: Map<string, string> | undefined;
	#devStoragePrefix = 'scorm-dev:';

	get version(): ScormVersion | undefined {
		return this.#version;
	}

	get isDev(): boolean {
		return this.#devStore !== undefined;
	}

	connect(courseId?: string): 'lms' | 'dev' {
		this.#devStoragePrefix = courseId ? `scorm-dev:${courseId}:` : 'scorm-dev:';
		const api2004 = findScorm2004API();
		if (api2004) {
			this.#api2004 = api2004;
			this.#version = '2004';
			return 'lms';
		}

		const api12 = findScorm12API();
		if (api12) {
			this.#api12 = api12;
			this.#version = '1.2';
			return 'lms';
		}

		this.#devStore = new Map<string, string>();
		this.#loadDevStore();
		return 'dev';
	}

	initialize(): boolean {
		if (this.#devStore !== undefined) return true;
		if (this.#api2004) return this.#api2004.Initialize('') === 'true';
		if (this.#api12) return this.#api12.LMSInitialize('') === 'true';
		return false;
	}

	terminate(): boolean {
		if (this.#devStore !== undefined) return true;
		if (this.#api2004) return this.#api2004.Terminate('') === 'true';
		if (this.#api12) return this.#api12.LMSFinish('') === 'true';
		return false;
	}

	commit(): boolean {
		if (this.#devStore !== undefined) return true;
		if (this.#api2004) return this.#api2004.Commit('') === 'true';
		if (this.#api12) return this.#api12.LMSCommit('') === 'true';
		return false;
	}

	getValue(element: string): string {
		if (this.#devStore !== undefined) return this.#devStore.get(element) ?? '';
		if (this.#api2004) return this.#api2004.GetValue(element);
		if (this.#api12) return this.#api12.LMSGetValue(element);
		return '';
	}

	setValue(element: string, value: string): boolean {
		if (this.#devStore !== undefined) {
			this.#devStore.set(element, value);
			localStorage.setItem(`${this.#devStoragePrefix}${element}`, value);
			return true;
		}
		if (this.#api2004) return this.#api2004.SetValue(element, value) === 'true';
		if (this.#api12) return this.#api12.LMSSetValue(element, value) === 'true';
		return false;
	}

	getLastErrorCode(): number {
		if (this.#devStore !== undefined) return 0;
		if (this.#api2004) {
			const retrieve = this.#api2004.GetLastError.bind(this.#api2004);
			return Number.parseInt(retrieve(), DECIMAL_RADIX);
		}
		if (this.#api12) {
			const retrieve = this.#api12.LMSGetLastError.bind(this.#api12);
			return Number.parseInt(retrieve(), DECIMAL_RADIX);
		}
		return 0;
	}

	getErrorDescription(errorCode: number): string {
		const code = String(errorCode);
		if (this.#api2004) return this.#api2004.GetErrorString(code);
		if (this.#api12) return this.#api12.LMSGetErrorString(code);
		return '';
	}

	getDiagnosticInfo(errorCode: number): string {
		const code = String(errorCode);
		if (this.#api2004) return this.#api2004.GetDiagnostic(code);
		if (this.#api12) return this.#api12.LMSGetDiagnostic(code);
		return '';
	}

	formatSessionTime(elapsedMs: number): string {
		if (this.#version === '2004') return formatSessionTime2004(elapsedMs);
		return formatSessionTime12(elapsedMs);
	}

	#loadDevStore(): void {
		for (let index = 0; index < localStorage.length; index++) {
			const key = localStorage.key(index);
			if (key?.startsWith(this.#devStoragePrefix)) {
				const element = key.slice(this.#devStoragePrefix.length);
				this.#devStore!.set(element, localStorage.getItem(key) || '');
			}
		}
	}
}