import {
	DEFAULT_PROJECTION,
	PLANE_2D_DISTANCE,
	PLANE_DISTANCE,
	PLAYER_SELECTOR,
	type ProjectionMode,
	VALID_PROJECTIONS
} from './config.js';
import { createContentScene } from './content-scene.js';
import { create2DControlPanel, createPlayButton, injectPlayerStyles } from './dom.js';
import {
	applySbsTextureWindow as applySbsTextureWindowCore,
	hideContentMeshes as hideContentMeshesCore,
	positionPlaneForPresentation as positionPlaneForPresentationCore,
	showActiveContentMesh as showActiveContentMeshCore
} from './projection.js';
import { createVideoTexture as createVideoTextureCore } from './three-utils.js';
import { FallbackCameraControls } from './fallback-camera-controls.js';
import { MediaController } from './media-controller.js';
import {
	createVrController,
	handleVrControllerSelect
} from './vr-controller-interactions.js';
import { bindVideoEvents } from './video-events.js';
import {
	createVrControlPanel,
	type VrControlPanel,
	updateVrPlayPauseButtonIcon,
	updateVrSeekBarAppearance,
	updateVrVolumeButtonIcon
} from './vr-control-panel.js';
import { VrPanelVisibility } from './vr-panel-visibility.js';
import { TwoDMode } from './two-d-mode.js';
import {
	createPlayerRenderer,
	resizePlayerRenderer
} from './renderer-lifecycle.js';

const _playerBase = new URL('.', import.meta.url).href;

let playerContainer, projectionMode: ProjectionMode = DEFAULT_PROJECTION;
let scene, camera, renderer, video, videoTexture, sphereMaterial;
let vr180Mesh, planeMesh, activeContentMesh;
let xrSession = null;
let raycaster, uiElements = [];
let videoElement, playBtn;
let frameCounter = 0;

let isXrLoopActive = false;
let vrControlPanel;
let mediaController: MediaController | undefined;
let vrPanel: VrControlPanel | undefined;
let twoDMode: TwoDMode | undefined;
const vrPanelVisibility = new VrPanelVisibility();

// 2D Camera Controls
let camera2D;
let fallbackCameraControls: FallbackCameraControls | undefined;

injectPlayerStyles(_playerBase);

document.addEventListener('DOMContentLoaded', () => {
	const containers = document.querySelectorAll(PLAYER_SELECTOR);
	
	if (containers.length === 0) {
		console.error(`VR_WEB_PLAYER_DOM: Expected exactly one ${PLAYER_SELECTOR} container, found none.`);
		return;
	}

	if (containers.length > 1) {
		console.warn(`VR_WEB_PLAYER_DOM: This version supports exactly one ${PLAYER_SELECTOR} container per page. Found ${containers.length}; no player was initialized.`);
		return;
	}

	playerContainer = containers[0];
	playerContainer.classList.add('vrwp');

	const configuredProjection = (playerContainer.dataset.projection || DEFAULT_PROJECTION).trim().toLowerCase();
	if (!VALID_PROJECTIONS.has(configuredProjection as ProjectionMode)) {
		console.error(`VR_WEB_PLAYER_CONFIG: Unsupported data-projection="${configuredProjection}". Use "vr180" or "plane".`);
		return;
	}
	projectionMode = configuredProjection as ProjectionMode;

	videoElement = playerContainer.querySelector('video');
	if (!videoElement) {
		console.error(`VR_WEB_PLAYER_DOM: ${PLAYER_SELECTOR} must contain a video element.`);
		return;
	}
	videoElement.classList.add('vrwp-video');

	// Create and insert play button
	playBtn = createPlayButton();
	playerContainer.appendChild(playBtn);

	// Create and insert 2D control panel
	const controlPanel = create2DControlPanel();
	playerContainer.appendChild(controlPanel);

	playBtn.disabled = true;
	
	if (videoElement) {
		videoElement.load();
	}

	if (navigator.xr) {
		navigator.xr.isSessionSupported('immersive-vr').then((supported) => {
			if (supported) {
				playBtn.dataset.xrSupported = "true";
			} else {
				playBtn.dataset.xrSupported = "false";
				// Enable button for regular video playback when VR is not supported
				playBtn.disabled = false;
			}
			// Always call init() regardless of VR support
			init();
		}).catch(err => {
			console.error("XR Support Check Error:", err);
			playBtn.dataset.xrSupported = "false";
			// Enable button for regular video playback when VR check fails
			playBtn.disabled = false;
			// Call init() even when VR check fails
			init();
		});
	} else {
		playBtn.dataset.xrSupported = "false";
		// If navigator.xr itself is not available, enable button for regular video playback
		if (playBtn) {
			playBtn.disabled = false;
		}
		// Call init() even when XR is not available
		init();
	}
});

function applySbsTextureWindow(renderingRenderer, activeCamera, material) {
	applySbsTextureWindowCore(renderingRenderer, activeCamera, material, is2DModeActive());
}

function hideContentMeshes() {
	hideContentMeshesCore(vr180Mesh, planeMesh);
}

function showActiveContentMesh() {
	showActiveContentMeshCore(vr180Mesh, planeMesh, activeContentMesh);
}

function positionPlaneForPresentation(isFallback2D = false) {
	positionPlaneForPresentationCore(planeMesh, camera2D, isFallback2D, PLANE_DISTANCE, PLANE_2D_DISTANCE);
}

function createVideoTexture() {
	if (videoTexture) videoTexture.dispose();
	videoTexture = createVideoTextureCore(video);
	return videoTexture;
}

function is2DModeActive() {
	return twoDMode?.isActive ?? false;
}

function closeActiveXrSessionAfterContextLoss() {
	if (!xrSession) return;

	const sessionToClose = xrSession;
	xrSession = null;
	sessionToClose.removeEventListener('end', onVRSessionEnd);
	sessionToClose.end().catch(e => {
		console.error("Error ending session on context lost:", e);
	}).finally(() => {
		onVRSessionEnd({ session: sessionToClose });
	});
}

function restoreVideoTextureAfterContextRestored() {
	if (video && sphereMaterial && activeContentMesh && activeContentMesh.visible && renderer.xr.isPresenting && xrSession) {
		videoTexture = createVideoTexture();
		sphereMaterial.map = videoTexture;
		sphereMaterial.needsUpdate = true;
		updateVRPlayPauseButtonIcon();
		updateVRVolumeButtonIcon();
		console.log("Re-initialized video texture after context restoration during VR.");
	}
}

function getVideoTitle() {
	return videoElement.getAttribute('title') ||
		videoElement.querySelector('source')?.src.split('/').pop()?.split('.')[0].replace(/-/g, ' ') ||
		"Video Title";
}


function init() {
	try {
		const playerRenderer = createPlayerRenderer(playerContainer, {
			closeActiveXrSession: closeActiveXrSessionAfterContextLoss,
			hasActiveXrSession: () => !!xrSession,
			restoreAfterContextRestored: restoreVideoTextureAfterContextRestored
		});
		scene = playerRenderer.scene;
		camera = playerRenderer.camera;
		renderer = playerRenderer.renderer;

		video = videoElement;
		mediaController = new MediaController({
			is2DModeActive,
			on2DPlaybackResume: show2DControlPanel,
			playButton: playBtn,
			video
		});
		const contentScene = createContentScene(scene, projectionMode, (renderer, scene, activeCamera, geometry, material, group) => {
			applySbsTextureWindow(renderer, activeCamera, material);
		});
		sphereMaterial = contentScene.material;
		vr180Mesh = contentScene.vr180Mesh;
		planeMesh = contentScene.planeMesh;
		activeContentMesh = contentScene.activeContentMesh;
		uiElements.push(activeContentMesh);

		camera2D = contentScene.fallbackCamera;
		fallbackCameraControls = new FallbackCameraControls(camera2D, {
			hideControls: hide2DControlPanel,
			isEnabled: is2DModeActive,
			showControls: show2DControlPanel
		});
		twoDMode = new TwoDMode({
			callbacks: {
				createMediaTexture: createVideoTexture,
				forward: () => mediaController?.forward(),
				positionPlaneForPresentation,
				rewind: () => mediaController?.rewind(),
				seekToProgress: (progress) => mediaController?.seekToProgress(progress),
				showActiveContentMesh,
				toggleMute: () => mediaController?.toggleMute(),
				togglePlayPause: () => mediaController?.togglePlayPause()
			},
			fullscreenTarget: playerContainer,
			getActiveContentMesh: () => activeContentMesh,
			getCamera: () => camera2D,
			getCameraControls: () => fallbackCameraControls,
			getMaterial: () => sphereMaterial,
			getRenderer: () => renderer,
			getScene: () => scene,
			getVideo: () => video,
			playerContainer,
			projectionMode,
			title: getVideoTitle()
		});
	} catch (e) {
		console.error("INIT_ERROR (Phase 1 - Core Setup):", e);
		renderer = null;
		return;
	}

	try { // Phase 2: VR Control Panel UI
		vrPanel = createVrControlPanel(scene, getVideoTitle());
		vrControlPanel = vrPanel.group;
		vrPanelVisibility.setPanel(vrPanel);
		uiElements.push(...vrPanel.interactables);

		raycaster = createVrController(scene, renderer, onSelectStartVR).raycaster;
	} catch (e) {
		console.error("INIT_ERROR (Phase 2 - VR Controls Setup):", e);
	}

	try { // Phase 3: Event Listeners
		if (playBtn) {
			playBtn.addEventListener('click', handleEnterVRButtonClick);
		}
		window.addEventListener('resize', onWindowResize);

		if (video) {
			bindVideoEvents({
				onEnded: onVideoEnded,
				onPlaybackStateChange: () => {
					updateVRPlayPauseButtonIcon();
					update2DPlayPauseButton();
				},
				onTimelineChange: () => {
					updateSeekBarAppearance();
					update2DControlPanel();
				},
				onVolumeChange: () => {
					updateVRVolumeButtonIcon();
					update2DMuteButton();
				},
				playButton: playBtn,
				video
			});
		}
	} catch (e) {
		console.error("INIT_ERROR (Phase 3 - Event Listeners):", e);
	}
}


function updateVRPlayPauseButtonIcon() {
	if (!video) {
		return;
	}
	updateVrPlayPauseButtonIcon(vrPanel, video.paused || video.ended);
}

function updateVRVolumeButtonIcon() {
	if (!video) {
		return;
	}
	updateVrVolumeButtonIcon(vrPanel, video.muted || video.volume === 0);
}

function updateSeekBarAppearance() {
	const progress = video && isFinite(video.duration) && video.duration > 0
		? video.currentTime / video.duration
		: null;
	updateVrSeekBarAppearance(vrPanel, progress);
}

function animatePanelFade(timestamp) {
	vrPanelVisibility.updateFade(timestamp);
}

function showPanel() {
	vrPanelVisibility.show();
}

function hidePanel() {
	vrPanelVisibility.hide();
}

function onWindowResize() {
	if (!renderer) return;

	if (twoDMode?.resize()) return;

	resizePlayerRenderer({
		camera,
		camera2D,
		is2DMode: false,
		onFallbackResize: () => {},
		playerContainer,
		renderer
	});
}

function show2DControlPanel() {
	twoDMode?.showControls();
}

function hide2DControlPanel() {
	twoDMode?.hideControls();
}

function update2DControlPanel() {
	twoDMode?.updateTimeline();
}

function update2DPlayPauseButton() {
	twoDMode?.updatePlaybackButton();
}

function update2DMuteButton() {
	twoDMode?.updateMuteButton();
}

function handle2DVideoEnd() {
	twoDMode?.handleVideoEnd();
}

function resetToOriginalState() {
	if (mediaController) {
		mediaController.resetToOriginalState();
	} else if (playBtn) {
		playBtn.classList.remove('hidden');
		playBtn.disabled = false;
	}
	
	if (twoDMode?.isActive) {
		twoDMode.stop();
		onWindowResize();
	}
}

function onVideoEnded() {
	if (!mediaController) {
		resetToOriginalState();
		return;
	}

	mediaController.handleEnded({
		cleanupFailedVrExit,
		exitVr: actualSessionToggle,
		isIn2DMode: is2DModeActive,
		isInVr: () => Boolean(xrSession && renderer && renderer.xr.isPresenting),
		on2DEnded: handle2DVideoEnd,
		resetToOriginalState
	});
}

function cleanupFailedVrExit() {
	if (xrSession) {
		const sessionToClean = xrSession;
		xrSession = null;
		sessionToClean.removeEventListener('end', onVRSessionEnd);
		sessionToClean.end().catch(e => {}).finally(() => onVRSessionEnd({session: sessionToClean}));
	} else {
		 onVRSessionEnd({session: null});
	}
}

function onSelectStartVR(event) {
	handleVrControllerSelect(event, {
		exitVr: () => {
			if (xrSession) actualSessionToggle();
		},
		forward: () => {
			mediaController?.forward();
			updateSeekBarAppearance();
		},
		hidePanel,
		isPanelVisible: () => vrPanelVisibility.isVisible,
		raycaster,
		rewind: () => {
			mediaController?.rewind();
			updateSeekBarAppearance();
		},
		seek: (progress) => {
			mediaController?.seekToProgress(progress);
			updateSeekBarAppearance();
		},
		showPanel,
		toggleMute: () => {
			mediaController?.toggleMute();
		},
		togglePlayPause: () => {
			mediaController?.togglePlayPause();
		},
		uiElements,
		vrPanel
	});
}

async function handleEnterVRButtonClick() {
	if (!video) {
		console.error("Video element not found for VR button click.");
		return;
	}
	
	// Hide the play button after click
	mediaController?.hidePlayButton();
	
	// Check if VR is supported
	if (playBtn.dataset.xrSupported === "true") {
		// VR is supported - use VR functionality
		await actualSessionToggle();
	} else {
		// VR is not supported - start 2D rectilinear mode
		twoDMode?.start();
	}
}

async function actualSessionToggle() {
	if (!renderer || !renderer.isWebGLRenderer) {
		console.error("CRITICAL_ERROR: actualSessionToggle: renderer is NOT a WebGLRenderer or is null!", renderer);
		return;
	}

	if (xrSession) { // --- EXITING VR ---
		const sessionToClose = xrSession;
		xrSession = null;

		if (vrControlPanel) {
			vrPanelVisibility.hideImmediately();
		}
		sessionToClose.end().catch(err => {
			console.error("Error calling .end() on session:", err);
			onVRSessionEnd({ session: sessionToClose });
		});
	} else { // --- ENTERING VR ---
		try {
			const session = await navigator.xr.requestSession('immersive-vr', {
				requiredFeatures: ['local-floor'],
			});
			if (!session) { throw new Error("requestSession returned no session."); }

			xrSession = session; 
			xrSession.addEventListener('end', onVRSessionEnd); 


			// Hide the regular video element when entering VR
			if (video) {
				video.style.display = 'none';
			}

			if (mediaController && video && (video.paused || video.ended)) {
				try {
					await mediaController.play();
				} catch (playError) {
					console.error("Failed to play video after obtaining XR session:", playError);
				}
			}

			if (camera) camera.updateProjectionMatrix();
			positionPlaneForPresentation(false);

			if (videoTexture) { videoTexture.dispose(); videoTexture = null; }
			if (video) {
				videoTexture = createVideoTexture();
				if (activeContentMesh && sphereMaterial) {
					sphereMaterial.map = videoTexture;
					sphereMaterial.needsUpdate = true;
					showActiveContentMesh();
				} else { throw new Error("VR mesh components not ready for texture."); }
			} else {
				throw new Error("Video element not available for creating texture.");
			}

			updateVRPlayPauseButtonIcon();
			updateVRVolumeButtonIcon();
			if (vrControlPanel) {
				vrPanelVisibility.hideImmediately();
			}

			await renderer.xr.setSession(xrSession);
			isXrLoopActive = true;
			renderer.setAnimationLoop(renderXR);
			frameCounter = 0;

		} catch (err) {
			const sessionStartError = "XR_ERROR: Failed to start VR session: " + (err.message || String(err));
			console.error(sessionStartError, err);
			isXrLoopActive = false;

			hideContentMeshes();
			if (sphereMaterial) { sphereMaterial.map = null; sphereMaterial.needsUpdate = true; }
			if (videoTexture) { videoTexture.dispose(); videoTexture = null; }
			if (vrControlPanel) {
				vrPanelVisibility.hideImmediately();
			}
			if (xrSession) { 
				xrSession.removeEventListener('end', onVRSessionEnd);
				const tempSession = xrSession;
				xrSession = null; 
				tempSession.end().catch(e => {}).finally(() => {
					onVRSessionEnd({session: tempSession});
				});
			} else {
				 onVRSessionEnd({session: null});
			}
			if (renderer && renderer.getAnimationLoop && renderer.getAnimationLoop()) {
				renderer.setAnimationLoop(null);
			}
		}
	}
}

function onVRSessionEnd(event) { 
	const endedSession = event.session; 

	isXrLoopActive = false;
	if (renderer) {
		if (renderer.getAnimationLoop && renderer.getAnimationLoop()) {
			renderer.setAnimationLoop(null);
		}
	}

	// Show the regular video element when exiting VR
	if (video) {
		video.style.display = '';
	}

	mediaController?.pauseIfPlaying();

	if (sphereMaterial && sphereMaterial.map) {
		sphereMaterial.map.dispose();
		sphereMaterial.map = null;
		sphereMaterial.needsUpdate = true;
	}
	if (videoTexture) {
		videoTexture.dispose(); videoTexture = null;
	}
	hideContentMeshes();
	if (vrControlPanel) {
		vrPanelVisibility.hideImmediately();
	}

	if (endedSession && typeof endedSession.removeEventListener === 'function') {
		endedSession.removeEventListener('end', onVRSessionEnd);
	}

	if (xrSession === endedSession || xrSession === null) {
		xrSession = null;
	} else if (xrSession && endedSession) {
		console.warn("onVRSessionEnd: Global xrSession was different from the endedSession. Global xrSession:", xrSession, "Ended session:", endedSession);
		xrSession = null;
	}

	// Reset to original state when exiting VR
	resetToOriginalState();

	onWindowResize();
}


function renderXR(timestamp, frame) {
	if (!isXrLoopActive) {
		return;
	}
	frameCounter++;

	if (!renderer || !renderer.xr || !renderer.xr.isPresenting) {
		console.warn("renderXR called but not in a valid XR presenting state. Stopping loop.");
		isXrLoopActive = false;
		if (renderer && renderer.getAnimationLoop && renderer.getAnimationLoop()) {
			renderer.setAnimationLoop(null);
		}
		return;
	}

	if (vrPanelVisibility.isFading) {
		animatePanelFade(timestamp);
	}

	if (!frame) {
		console.warn("renderXR called without an XRFrame. Skipping render.");
		return;
	}

	if (frameCounter > 0 && frameCounter % 3600 === 0) {
		const gl = renderer.getContext();
		const error = gl.getError();
		if (error !== gl.NO_ERROR) {
			console.error(`WEBGL_ERROR_IN_RENDER_LOOP (F${frameCounter}):`, error, gl.enumToString ? gl.enumToString(error) : error);
		}
	}
	try {
		// Sync video texture before render to ensure frame consistency
		if (videoTexture && video && !video.paused && !video.ended) {
			videoTexture.needsUpdate = true;
		}
		renderer.render(scene, camera);
	} catch (error) {
		const renderErrorMsg = "ERROR_IN_RENDERXR_LOOP (F" + frameCounter + "): " + (error.message || String(error));
		console.error(renderErrorMsg, error);
		console.error("Render loop error. Attempting to exit VR.");
		isXrLoopActive = false; 

		const sessionToCloseOnError = xrSession; 
		xrSession = null; 

		if (sessionToCloseOnError) {
			sessionToCloseOnError.removeEventListener('end', onVRSessionEnd);
			sessionToCloseOnError.end().catch(e => {
				console.error("Error trying to end session after render loop crash:", e);
			}).finally(() => {
				onVRSessionEnd({ session: sessionToCloseOnError });
			});
		} else {
			onVRSessionEnd({ session: null }); 
		}
	}
}