// skin_manager.js
// Handles skin uploading, conversion, 3D preview, and saving to char.png

let mainMenuScene, mainMenuCamera, mainMenuRenderer, mainMenuPlayerGroup;
let isMainSkinDragging = false;
let mainMenuSkinRenderMode = '3d';

let skinScene, skinCamera, skinRenderer, skinPlayerGroup;
let isSkinDragging = false;
let previousSkinMousePosition = { x: 0, y: 0 };
let processedSkinDataUrl = null;

// Initialize when DOM is ready
document.addEventListener('DOMContentLoaded', () => {
    const skinInput = document.getElementById('skin-input');
    const dropZone = document.getElementById('drop-zone');
    const saveSkinBtn = document.getElementById('save-skin-btn');
    const closeSkinBtn = document.getElementById('btn-close-skin');

    if (skinInput) skinInput.addEventListener('change', (e) => handleSkinFile(e.target.files[0]));
    
    if (dropZone) {
        dropZone.addEventListener('click', () => skinInput?.click());
        dropZone.addEventListener('keydown', (e) => {
            if (e.key === 'Enter' || e.key === ' ') {
                e.preventDefault();
                skinInput?.click();
            }
        });
        dropZone.addEventListener('dragover', (e) => { 
            e.preventDefault(); 
            dropZone.classList.add('border-green-500'); 
        });
        dropZone.addEventListener('dragleave', () => dropZone.classList.remove('border-green-500'));
        dropZone.addEventListener('drop', (e) => { 
            e.preventDefault(); 
            dropZone.classList.remove('border-green-500');
            handleSkinFile(e.dataTransfer.files[0]); 
        });
    }

    if (saveSkinBtn) {
        saveSkinBtn.addEventListener('click', saveSkinToDisk);
    }

    if (closeSkinBtn) {
        closeSkinBtn.addEventListener('click', closeSkinManager);
    }

    // Initialize Main Menu Viewer
    initMainMenuSkinViewer();
});

function initMainMenuSkinViewer() {
    const container = document.getElementById('main-skin-viewer');
    if (!container) return;

    mainMenuScene = new THREE.Scene();
    mainMenuCamera = new THREE.PerspectiveCamera(45, container.offsetWidth / container.offsetHeight, 0.1, 1000);
    mainMenuCamera.position.set(0, 5, 60); 

    mainMenuRenderer = new THREE.WebGLRenderer({ antialias: true, alpha: true });
    mainMenuRenderer.setSize(container.offsetWidth, container.offsetHeight);
    mainMenuRenderer.setPixelRatio(window.devicePixelRatio);
    mainMenuRenderer.outputEncoding = THREE.sRGBEncoding;
    container.appendChild(mainMenuRenderer.domElement);

    mainMenuScene.add(new THREE.AmbientLight(0xffffff, 1.1));
    const dl = new THREE.DirectionalLight(0xffffff, 0.5);
    dl.position.set(10, 20, 15);
    mainMenuScene.add(dl);

    mainMenuPlayerGroup = new THREE.Group();
    mainMenuScene.add(mainMenuPlayerGroup);

    // Interaction for Main Menu Viewer
    let prevX = 0;
    container.addEventListener('mousedown', (e) => {
        if (mainMenuSkinRenderMode !== '3d') return;
        isMainSkinDragging = true;
        prevX = e.clientX;
    });
    window.addEventListener('mouseup', () => isMainSkinDragging = false);
    window.addEventListener('mousemove', (e) => {
        if (mainMenuSkinRenderMode === '3d' && isMainSkinDragging && mainMenuPlayerGroup) {
            mainMenuPlayerGroup.rotation.y += (e.clientX - prevX) * 0.01;
            prevX = e.clientX;
        }
    });

    // Auto-rotate slowly
    function animateMain() {
        requestAnimationFrame(animateMain);
        if (mainMenuSkinRenderMode === '3d' && !isMainSkinDragging && mainMenuPlayerGroup) {
            mainMenuPlayerGroup.rotation.y += 0.005;
        }
        if (mainMenuRenderer && mainMenuScene && mainMenuCamera) mainMenuRenderer.render(mainMenuScene, mainMenuCamera);
    }
    animateMain();

    // Load current skin after short delay to ensure paths are ready
    setTimeout(loadMainMenuSkin, 500);

    // Handle window resize
    window.addEventListener('resize', () => {
        if (mainMenuCamera && mainMenuRenderer && container) {
            mainMenuCamera.aspect = container.offsetWidth / container.offsetHeight;
            mainMenuCamera.updateProjectionMatrix();
            mainMenuRenderer.setSize(container.offsetWidth, container.offsetHeight);
        }
    });
}

async function loadMainMenuSkin() {
    try {
        // Ensure install dir is available (currentInstance might not be ready)
        const installDir = await window.getInstallDir();
        if (!installDir) return;
        
        const skinPath = path.join(installDir, 'Common', 'res', 'mob', 'char.png');
        
        if (fs.existsSync(skinPath)) {
            const skinData = fs.readFileSync(skinPath);
            const blob = new Blob([skinData]);
            const url = URL.createObjectURL(blob);
            
            const img = new Image();
            img.onload = () => {
                const isLegacy = img.height === 32;
                updateSkinModel(img.src, isLegacy, mainMenuPlayerGroup, mainMenuSkinRenderMode);
            };
            img.src = url;
        } else {
            console.log("No skin found at " + skinPath);
        }
    } catch (e) {
        console.warn("Could not load main menu skin (startup race condition?):", e);
    }
}

function toggleMainSkinRenderMode() {
    mainMenuSkinRenderMode = mainMenuSkinRenderMode === '3d' ? '2d' : '3d';
    const modeButton = document.getElementById('btn-skin-render-mode');
    if (modeButton) modeButton.textContent = mainMenuSkinRenderMode.toUpperCase();

    const container = document.getElementById('main-skin-viewer');
    if (container) {
        container.style.cursor = mainMenuSkinRenderMode === '3d' ? 'grab' : 'default';
    }
    isMainSkinDragging = false;

    if (mainMenuSkinRenderMode === '2d' && mainMenuPlayerGroup) {
        mainMenuPlayerGroup.rotation.y = 0;
    }

    loadMainMenuSkin();
}

function updateSkinModel(dataUrl, isLegacy, targetGroup, renderMode = '3d') {
    if (!targetGroup) return;

    new THREE.TextureLoader().load(dataUrl, (texture) => {
        texture.magFilter = THREE.NearestFilter;
        texture.minFilter = THREE.NearestFilter;
        texture.encoding = THREE.sRGBEncoding;

        // Clear existing children
        while(targetGroup.children.length > 0) targetGroup.remove(targetGroup.children[0]);

        const createFaceMaterial = (tex, x, y, w, h) => {
            const texWidth = tex.image.width;
            const texHeight = tex.image.height;
            const matTex = tex.clone();
            matTex.magFilter = THREE.NearestFilter;
            matTex.minFilter = THREE.NearestFilter;
            matTex.repeat.set(w / texWidth, h / texHeight);
            matTex.offset.set(x / texWidth, 1 - (y + h) / texHeight);
            matTex.needsUpdate = true;
            return new THREE.MeshLambertMaterial({ map: matTex, transparent: true, alphaTest: 0.5, side: THREE.FrontSide });
        };

        const createBodyPart = (w, h, d, tex, uv, offset = 0) => {
            const geometry = new THREE.BoxGeometry(w, h, d);
            const materials = [
                createFaceMaterial(tex, uv.left[0], uv.left[1], uv.left[2], uv.left[3]), // Left (Standard MC "Right")
                createFaceMaterial(tex, uv.right[0], uv.right[1], uv.right[2], uv.right[3]), // Right (Standard MC "Left")
                createFaceMaterial(tex, uv.top[0], uv.top[1], uv.top[2], uv.top[3]),
                createFaceMaterial(tex, uv.bottom[0], uv.bottom[1], uv.bottom[2], uv.bottom[3]),
                createFaceMaterial(tex, uv.front[0], uv.front[1], uv.front[2], uv.front[3]),
                createFaceMaterial(tex, uv.back[0], uv.back[1], uv.back[2], uv.back[3])
            ];
            const mesh = new THREE.Mesh(geometry, materials);
            if (offset !== 0) mesh.scale.set(1 + offset, 1 + offset, 1 + offset);
            return mesh;
        };

        const limbUv = (x, y) => ({
            top: [x+4, y, 4, 4], bottom: [x+8, y, 4, 4],
            right: [x, y+4, 4, 12], front: [x+4, y+4, 4, 12],
            left: [x+8, y+4, 4, 12], back: [x+12, y+4, 4, 12]
        });

        const create2DPart = (tex, uvFront, width, height, x, y, scale = 1) => {
            const texWidth = tex.image.width;
            const texHeight = tex.image.height;
            const partTex = tex.clone();
            partTex.magFilter = THREE.NearestFilter;
            partTex.minFilter = THREE.NearestFilter;
            partTex.repeat.set(uvFront[2] / texWidth, uvFront[3] / texHeight);
            partTex.offset.set(uvFront[0] / texWidth, 1 - (uvFront[1] + uvFront[3]) / texHeight);
            partTex.needsUpdate = true;

            const geometry = new THREE.PlaneGeometry(width, height);
            const material = new THREE.MeshBasicMaterial({ map: partTex, transparent: true, alphaTest: 0.5, side: THREE.DoubleSide });
            const mesh = new THREE.Mesh(geometry, material);
            mesh.position.set(x, y, 0);
            mesh.scale.set(scale, scale, 1);
            return mesh;
        };

        if (renderMode === '2d') {
            const frontParts = [
                create2DPart(texture, [8, 8, 8, 8], 8, 8, 0, 10),
                create2DPart(texture, [40, 8, 8, 8], 8, 8, 0, 10, 1.12),
                create2DPart(texture, [20, 20, 8, 12], 8, 12, 0, 0),
                create2DPart(texture, [44, 20, 4, 12], 4, 12, -6, 0),
                create2DPart(texture, isLegacy ? [44, 20, 4, 12] : [36, 52, 4, 12], 4, 12, 6, 0),
                create2DPart(texture, [4, 20, 4, 12], 4, 12, -2, -12),
                create2DPart(texture, isLegacy ? [4, 20, 4, 12] : [20, 52, 4, 12], 4, 12, 2, -12)
            ];

            if (!isLegacy) {
                frontParts.push(
                    create2DPart(texture, [20, 36, 8, 12], 8, 12, 0, 0, 1.05),
                    create2DPart(texture, [44, 36, 4, 12], 4, 12, -6, 0, 1.05),
                    create2DPart(texture, [52, 52, 4, 12], 4, 12, 6, 0, 1.05),
                    create2DPart(texture, [4, 36, 4, 12], 4, 12, -2, -12, 1.05),
                    create2DPart(texture, [4, 52, 4, 12], 4, 12, 2, -12, 1.05)
                );
            }

            frontParts.forEach((part) => targetGroup.add(part));
            targetGroup.rotation.y = 0;
            return;
        }

        // Head
        const headUvs = { top: [8, 0, 8, 8], bottom: [16, 0, 8, 8], right: [0, 8, 8, 8], left: [16, 8, 8, 8], front: [8, 8, 8, 8], back: [24, 8, 8, 8] };
        const head = createBodyPart(8, 8, 8, texture, headUvs);
        head.position.y = 10;
        targetGroup.add(head);

        // Hat
        const hatUvs = { top: [40, 0, 8, 8], bottom: [48, 0, 8, 8], right: [32, 8, 8, 8], left: [48, 8, 8, 8], front: [40, 8, 8, 8], back: [56, 8, 8, 8] };
        const hat = createBodyPart(8, 8, 8, texture, hatUvs, 0.12);
        hat.position.y = 10;
        targetGroup.add(hat);

        // Torso
        const torsoUvs = { top: [20, 16, 8, 4], bottom: [28, 16, 8, 4], right: [16, 20, 4, 12], left: [28, 20, 4, 12], front: [20, 20, 8, 12], back: [32, 20, 8, 12] };
        targetGroup.add(createBodyPart(8, 12, 4, texture, torsoUvs));

        // Jacket (non-legacy only)
        if (!isLegacy) {
            const jacketUvs = { top: [20, 32, 8, 4], bottom: [28, 32, 8, 4], right: [16, 36, 4, 12], left: [28, 36, 4, 12], front: [20, 36, 8, 12], back: [32, 36, 8, 12] };
            targetGroup.add(createBodyPart(8, 12, 4, texture, jacketUvs, 0.05));
        }

        // Limbs
        const limbs = [
            { pos: [-6, 0, 0], uv: limbUv(40, 16), layerUv: limbUv(40, 32) },
            { pos: [6, 0, 0], uv: isLegacy ? limbUv(40, 16) : limbUv(32, 48), layerUv: limbUv(48, 48) },
            { pos: [-2, -12, 0], uv: limbUv(0, 16), layerUv: limbUv(0, 32) },
            { pos: [2, -12, 0], uv: isLegacy ? limbUv(0, 16) : limbUv(16, 48), layerUv: limbUv(0, 48) }
        ];

        limbs.forEach(l => {
            const base = createBodyPart(4, 12, 4, texture, l.uv);
            base.position.set(...l.pos);
            targetGroup.add(base);
            if (!isLegacy) {
                const layer = createBodyPart(4, 12, 4, texture, l.layerUv, 0.05);
                layer.position.set(...l.pos);
                targetGroup.add(layer);
            }
        });

        targetGroup.rotation.y = 0;
    });
}

function openSkinManager() {
    const modal = document.getElementById('skin-modal');
    modal.style.display = 'flex';
    modal.style.opacity = '1';
    
    // Clear previous state in modal
    const previewContainer = document.getElementById('preview-container');
    if (previewContainer) previewContainer.classList.add('hidden');
    
    const sysMsg = document.getElementById('sys-message');
    if (sysMsg) sysMsg.classList.add('hidden');
    
    // Load current skin into preview (optional, maybe we only want to see uploaded ones)
    // loadCurrentSkinToPreview(); 
}

function closeSkinManager() {
    const modal = document.getElementById('skin-modal');
    modal.style.opacity = '0';
    setTimeout(() => {
        modal.style.display = 'none';
        
        // Reset state
        const prompt = document.getElementById('upload-prompt');
        if (prompt) prompt.style.display = 'block';
        
        const previewContainer = document.getElementById('preview-container');
        if (previewContainer) previewContainer.classList.add('hidden');
        
        processedSkinDataUrl = null;
        
    }, 300);
}

function handleSkinFile(file) {
    if (!file || !file.type.includes('png')) return window.showToast("Only PNG files are supported!");
    
    const prompt = document.getElementById('upload-prompt');
    if (prompt) prompt.style.display = 'none';

    const reader = new FileReader();
    reader.onload = (e) => {
        const img = new Image();
        img.onload = () => {
            processSkinImage(img, e.target.result);
        };
        img.onerror = () => {
             window.showToast("Failed to load image");
             if(prompt) prompt.style.display = 'block';
        };
        img.src = e.target.result;
    };
    reader.readAsDataURL(file);
}

function processSkinImage(img, srcUrl, isInitialLoad = false) {
    const canvas = document.getElementById('skin-canvas');
    const ctx = canvas.getContext('2d');
    const formatLabel = document.getElementById('format-label');
    const statusMessage = document.getElementById('status-message');
    const previewContainer = document.getElementById('preview-container');
    const saveBtn = document.getElementById('save-skin-btn');
    const prompt = document.getElementById('upload-prompt');

    if (img.width !== 64) {
        if(prompt) prompt.style.display = 'block';
        if(previewContainer) previewContainer.classList.add('hidden');
        return window.showToast("Invalid skin width. Must be 64px.");
    }
    
    if(prompt) prompt.style.display = 'none';

    const isLegacy = img.height === 32;
    
    ctx.clearRect(0, 0, 64, 32);
    ctx.drawImage(img, 0, 0, 64, 32, 0, 0, 64, 32);
    processedSkinDataUrl = canvas.toDataURL('image/png');
    
    previewContainer.classList.remove('hidden');
    
    if (isInitialLoad) {
        if(formatLabel) formatLabel.textContent = "Current Skin";
        if(statusMessage) statusMessage.innerHTML = "<span class='text-blue-400 font-black' style='color: #60a5fa;'>LOADED FROM DISK</span>";
        if(saveBtn) {
            saveBtn.textContent = "SAVED";
            saveBtn.classList.add('disabled');
        }
    } else {
        if(formatLabel) formatLabel.textContent = isLegacy ? "64x32 (Legacy)" : "64x64 (Modern)";
        if(statusMessage) statusMessage.innerHTML = isLegacy ? "<span class='text-green-400 font-black' style='color: #4ade80;'>LEGACY READY</span>" : "<span class='text-yellow-400 font-black' style='color: #facc15;'>CONVERTED TO 64x32</span>";
        if(saveBtn) {
            saveBtn.textContent = "SAVE SKIN";
            saveBtn.classList.remove('disabled');
        }
    }
    
    if (!skinScene) initPreviewEngine();
    updateSkinModel(srcUrl, isLegacy, skinPlayerGroup, '3d');
}

function initPreviewEngine() {
    const container = document.getElementById('skin-viewer-container');
    if (!container) return;
    
    skinScene = new THREE.Scene();
    skinCamera = new THREE.PerspectiveCamera(35, container.offsetWidth / container.offsetHeight, 0.1, 1000);
    skinCamera.position.set(0, 5, 70); 

    skinRenderer = new THREE.WebGLRenderer({ antialias: false, alpha: true });
    skinRenderer.setSize(container.offsetWidth, container.offsetHeight);
    skinRenderer.setPixelRatio(window.devicePixelRatio);
    skinRenderer.outputEncoding = THREE.sRGBEncoding;
    container.appendChild(skinRenderer.domElement);

    skinScene.add(new THREE.AmbientLight(0xffffff, 0.9));
    const dl = new THREE.DirectionalLight(0xffffff, 0.35);
    dl.position.set(10, 20, 15);
    skinScene.add(dl);

    skinPlayerGroup = new THREE.Group();
    skinScene.add(skinPlayerGroup);

    container.addEventListener('mousedown', () => isSkinDragging = true);
    window.addEventListener('mouseup', () => isSkinDragging = false);
    window.addEventListener('mousemove', (e) => {
        if (isSkinDragging && skinPlayerGroup) {
            skinPlayerGroup.rotation.y += (e.movementX) * 0.01;
        }
    });

    function animate() {
        requestAnimationFrame(animate);
        if (!isSkinDragging && skinPlayerGroup) skinPlayerGroup.rotation.y += 0.008;
        if (skinRenderer && skinScene && skinCamera) skinRenderer.render(skinScene, skinCamera);
    }
    animate();
}

async function saveSkinToDisk() {
    if (!processedSkinDataUrl) return;

    try {
        const installDir = await window.getInstallDir();
        const savePath = path.join(installDir, 'Common', 'res', 'mob', 'char.png');
        const dir = path.dirname(savePath);

        if (!fs.existsSync(dir)) {
            fs.mkdirSync(dir, { recursive: true });
        }

        const base64Data = processedSkinDataUrl.replace(/^data:image\/png;base64,/, "");
        fs.writeFileSync(savePath, base64Data, 'base64');
        
        window.showToast("Skin Saved Successfully!");
        
        const saveBtn = document.getElementById('save-skin-btn');
        if(saveBtn) {
            saveBtn.textContent = "SAVED!";
            saveBtn.classList.add('disabled');
        }

        // Refresh main menu skin
        loadMainMenuSkin();
        
        // Close modal after short delay?
        setTimeout(closeSkinManager, 1000);

    } catch (e) {
        window.showToast("Error Saving Skin: " + e.message);
        console.error(e);
    }
}

// Global Export
window.openSkinManager = openSkinManager;
window.initMainMenuSkinViewer = initMainMenuSkinViewer;
window.loadMainMenuSkin = loadMainMenuSkin;
window.toggleMainSkinRenderMode = toggleMainSkinRenderMode;