/**
 * API Service – Backend communication for projects, drawings, elements, layers, blocks
 */
import type { CADElement, CADLayer, BlockDefinition } from '../types/cad.types';

const API_BASE = import.meta.env.VITE_API_BASE || '';

function authHeaders(token: string): Record<string, string> {
  return {
    'Content-Type': 'application/json',
    Authorization: `Bearer ${token}`,
  };
}

// ─── Types ──────────────────────────────────────────────
export interface Project {
  id: string;
  name: string;
  description: string | null;
  owner_id: string;
  created_at: string;
  updated_at: string;
}

export interface Drawing {
  id: string;
  project_id: string;
  name: string;
  created_at: string;
  updated_at: string;
}

// ─── Auth ───────────────────────────────────────────────
export async function login(email: string, password: string): Promise<{ user: any; session: { token: string } }> {
  const res = await fetch(`${API_BASE}/api/auth/login`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ email, password }),
  });
  if (!res.ok) throw new Error('Login failed');
  return res.json();
}

export async function register(email: string, password: string, name: string): Promise<{ user: any; session: { token: string } }> {
  const res = await fetch(`${API_BASE}/api/auth/register`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ email, password, name }),
  });
  if (!res.ok) throw new Error('Registration failed');
  return res.json();
}

export async function getMe(token: string): Promise<any> {
  const res = await fetch(`${API_BASE}/api/auth/me`, {
    headers: authHeaders(token),
  });
  if (!res.ok) throw new Error('Not authenticated');
  return res.json();
}

// ─── Projects ───────────────────────────────────────────
export async function getProjects(token: string): Promise<Project[]> {
  const res = await fetch(`${API_BASE}/api/projects`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load projects');
  return res.json();
}

export async function createProject(token: string, name: string, description?: string): Promise<Project> {
  const res = await fetch(`${API_BASE}/api/projects`, {
    method: 'POST',
    headers: authHeaders(token),
    body: JSON.stringify({ name, description: description || null }),
  });
  if (!res.ok) throw new Error('Failed to create project');
  return res.json();
}

export async function deleteProject(token: string, id: string): Promise<void> {
  await fetch(`${API_BASE}/api/projects/${id}`, {
    method: 'DELETE',
    headers: authHeaders(token),
  });
}

// ─── Drawings ───────────────────────────────────────────
export async function getDrawings(token: string, projectId: string): Promise<Drawing[]> {
  const res = await fetch(`${API_BASE}/api/projects/${projectId}/drawings`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load drawings');
  return res.json();
}

export async function createDrawing(token: string, projectId: string, name: string): Promise<Drawing> {
  const res = await fetch(`${API_BASE}/api/projects/${projectId}/drawings`, {
    method: 'POST',
    headers: authHeaders(token),
    body: JSON.stringify({ name }),
  });
  if (!res.ok) throw new Error('Failed to create drawing');
  return res.json();
}

// ─── Elements ───────────────────────────────────────────
export async function getElements(token: string, drawingId: string): Promise<CADElement[]> {
  const res = await fetch(`${API_BASE}/api/drawings/${drawingId}/elements`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load elements');
  return res.json();
}

export async function createElement(token: string, drawingId: string, el: CADElement): Promise<CADElement> {
  const res = await fetch(`${API_BASE}/api/drawings/${drawingId}/elements`, {
    method: 'POST',
    headers: authHeaders(token),
    body: JSON.stringify(el),
  });
  if (!res.ok) throw new Error('Failed to create element');
  return res.json();
}

export async function updateElement(token: string, elementId: string, patch: Partial<CADElement>): Promise<CADElement> {
  const res = await fetch(`${API_BASE}/api/elements/${elementId}`, {
    method: 'PATCH',
    headers: authHeaders(token),
    body: JSON.stringify(patch),
  });
  if (!res.ok) throw new Error('Failed to update element');
  return res.json();
}

export async function deleteElement(token: string, elementId: string): Promise<void> {
  await fetch(`${API_BASE}/api/elements/${elementId}`, {
    method: 'DELETE',
    headers: authHeaders(token),
  });
}

// ─── Layers ─────────────────────────────────────────────
export async function getLayers(token: string, drawingId: string): Promise<CADLayer[]> {
  const res = await fetch(`${API_BASE}/api/drawings/${drawingId}/layers`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load layers');
  return res.json();
}

export async function createLayer(token: string, drawingId: string, layer: CADLayer): Promise<CADLayer> {
  const res = await fetch(`${API_BASE}/api/drawings/${drawingId}/layers`, {
    method: 'POST',
    headers: authHeaders(token),
    body: JSON.stringify(layer),
  });
  if (!res.ok) throw new Error('Failed to create layer');
  return res.json();
}

export async function updateLayer(token: string, layerId: string, patch: Partial<CADLayer>): Promise<CADLayer> {
  const res = await fetch(`${API_BASE}/api/layers/${layerId}`, {
    method: 'PATCH',
    headers: authHeaders(token),
    body: JSON.stringify(patch),
  });
  if (!res.ok) throw new Error('Failed to update layer');
  return res.json();
}

export async function deleteLayer(token: string, layerId: string): Promise<void> {
  await fetch(`${API_BASE}/api/layers/${layerId}`, {
    method: 'DELETE',
    headers: authHeaders(token),
  });
}

// ─── Blocks ─────────────────────────────────────────────
export async function getBlocks(token: string, drawingId: string): Promise<BlockDefinition[]> {
  const res = await fetch(`${API_BASE}/api/drawings/${drawingId}/blocks`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load blocks');
  return res.json();
}

export async function createBlock(token: string, drawingId: string, block: BlockDefinition): Promise<BlockDefinition> {
  const res = await fetch(`${API_BASE}/api/drawings/${drawingId}/blocks`, {
    method: 'POST',
    headers: authHeaders(token),
    body: JSON.stringify(block),
  });
  if (!res.ok) throw new Error('Failed to create block');
  return res.json();
}

export async function updateBlock(token: string, blockId: string, patch: Partial<BlockDefinition>): Promise<BlockDefinition> {
  const res = await fetch(`${API_BASE}/api/blocks/${blockId}`, {
    method: 'PATCH',
    headers: authHeaders(token),
    body: JSON.stringify(patch),
  });
  if (!res.ok) throw new Error('Failed to update block');
  return res.json();
}

export async function deleteBlock(token: string, blockId: string): Promise<void> {
  await fetch(`${API_BASE}/api/blocks/${blockId}`, {
    method: 'DELETE',
    headers: authHeaders(token),
  });
}

// ─── Composite: Load full project data ───────────────────
export interface ProjectData {
  project: Project;
  drawing: Drawing | null;
  elements: CADElement[];
  layers: CADLayer[];
  blocks: BlockDefinition[];
}

export async function loadProjectData(token: string, projectId: string): Promise<ProjectData> {
  const drawings = await getDrawings(token, projectId);
  const project = (await getProjects(token)).find(p => p.id === projectId);
  
  if (!project) throw new Error('Project not found');
  
  // Use first drawing or create one
  let drawing = drawings[0] || null;
  if (!drawing) {
    drawing = await createDrawing(token, projectId, 'Hauptzeichnung');
  }
  
  const [elements, layers, blocks] = await Promise.all([
    getElements(token, drawing.id),
    getLayers(token, drawing.id),
    getBlocks(token, drawing.id),
  ]);
  
  return { project, drawing, elements, layers, blocks };
}

// ─── Format Conversion: DB (snake_case) ↔ Frontend (camelCase) ─────

function dbElementToFrontend(dbEl: any): CADElement {
  return {
    id: dbEl.id,
    type: dbEl.type,
    layerId: dbEl.layer_id,
    x: dbEl.x,
    y: dbEl.y,
    width: dbEl.width,
    height: dbEl.height,
    properties: typeof dbEl.properties_json === 'string'
      ? JSON.parse(dbEl.properties_json)
      : (dbEl.properties_json || {}),
  };
}

function frontendElementToDb(el: CADElement, drawingId: string): any {
  return {
    id: el.id,
    drawing_id: drawingId,
    layer_id: el.layerId,
    type: el.type,
    x: el.x,
    y: el.y,
    width: el.width,
    height: el.height,
    properties_json: JSON.stringify(el.properties),
  };
}

function dbLayerToFrontend(dbLayer: any): CADLayer {
  return {
    id: dbLayer.id,
    name: dbLayer.name,
    visible: !!dbLayer.visible,
    locked: !!dbLayer.locked,
    color: dbLayer.color,
    lineType: dbLayer.line_type as 'solid' | 'dashed' | 'dotted',
    transparency: dbLayer.transparency,
    sortOrder: dbLayer.sort_order,
    parentId: dbLayer.parent_id,
  };
}

function frontendLayerToDb(layer: CADLayer, drawingId: string): any {
  return {
    id: layer.id,
    drawing_id: drawingId,
    name: layer.name,
    visible: layer.visible ? 1 : 0,
    locked: layer.locked ? 1 : 0,
    color: layer.color,
    line_type: layer.lineType,
    transparency: layer.transparency,
    sort_order: layer.sortOrder,
    parent_id: layer.parentId,
  };
}

function dbBlockToFrontend(dbBlock: any): BlockDefinition {
  return {
    id: dbBlock.id,
    name: dbBlock.name,
    description: dbBlock.description || '',
    category: dbBlock.category,
    elements: typeof dbBlock.elements_json === 'string'
      ? JSON.parse(dbBlock.elements_json)
      : (dbBlock.elements_json || []),
    thumbnail: dbBlock.thumbnail || undefined,
  };
}

function frontendBlockToDb(block: BlockDefinition, drawingId: string): any {
  return {
    id: block.id,
    drawing_id: drawingId,
    name: block.name,
    description: block.description,
    category: block.category,
    elements_json: JSON.stringify(block.elements),
    thumbnail: block.thumbnail || null,
  };
}

// ─── Typed API calls with conversion ─────────────────────

export async function getElementsTyped(token: string, drawingId: string): Promise<CADElement[]> {
  const raw = await getElements(token, drawingId);
  return raw.map(dbElementToFrontend);
}

export async function createElementTyped(token: string, drawingId: string, el: CADElement): Promise<CADElement> {
  const raw = await createElement(token, drawingId, frontendElementToDb(el, drawingId));
  return dbElementToFrontend(raw);
}

export async function getLayersTyped(token: string, drawingId: string): Promise<CADLayer[]> {
  const raw = await getLayers(token, drawingId);
  return raw.map(dbLayerToFrontend);
}

export async function createLayerTyped(token: string, drawingId: string, layer: CADLayer): Promise<CADLayer> {
  const raw = await createLayer(token, drawingId, frontendLayerToDb(layer, drawingId));
  return dbLayerToFrontend(raw);
}

export async function getBlocksTyped(token: string, drawingId: string): Promise<BlockDefinition[]> {
  const raw = await getBlocks(token, drawingId);
  return raw.map(dbBlockToFrontend);
}

export async function createBlockTyped(token: string, drawingId: string, block: BlockDefinition): Promise<BlockDefinition> {
  const raw = await createBlock(token, drawingId, frontendBlockToDb(block, drawingId));
  return dbBlockToFrontend(raw);
}

const projectLoadCache = new Map<string, Promise<ProjectData>>();

export async function loadProjectDataTyped(token: string, projectId: string): Promise<ProjectData> {
  // Dedup concurrent calls (React StrictMode double-render)
  const existing = projectLoadCache.get(projectId);
  if (existing) return existing;

  const promise = (async () => {
    const drawings = await getDrawings(token, projectId);
    const projects = await getProjects(token);
    const project = projects.find(p => p.id === projectId);
    if (!project) throw new Error('Project not found');

    let drawing = drawings[0] || null;
    if (!drawing) {
      drawing = await createDrawing(token, projectId, 'Hauptzeichnung');
    }

    const [elementsRaw, layersRaw, blocksRaw] = await Promise.all([
      getElements(token, drawing.id),
      getLayers(token, drawing.id),
      getBlocks(token, drawing.id),
    ]);

    return {
      project,
      drawing,
      elements: elementsRaw.map(dbElementToFrontend),
      layers: layersRaw.map(dbLayerToFrontend),
      blocks: blocksRaw.map(dbBlockToFrontend),
    };
  })();

  projectLoadCache.set(projectId, promise);
  promise.finally(() => projectLoadCache.delete(projectId));
  return promise;
}

// ─── Notifications ───────────────────────────────────────
export interface NotificationItem {
  id: string;
  user_id: string;
  type: string;
  title: string;
  message: string;
  read: number;
  created_at: string;
}

export async function getNotifications(token: string): Promise<NotificationItem[]> {
  const res = await fetch(`${API_BASE}/api/notifications`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load notifications');
  return res.json();
}

export async function createNotification(token: string, data: { type?: string; title: string; message: string }): Promise<NotificationItem> {
  const res = await fetch(`${API_BASE}/api/notifications`, {
    method: 'POST',
    headers: { ...authHeaders(token), 'Content-Type': 'application/json' },
    body: JSON.stringify(data),
  });
  if (!res.ok) throw new Error('Failed to create notification');
  return res.json();
}

export async function markNotificationRead(token: string, id: string): Promise<void> {
  const res = await fetch(`${API_BASE}/api/notifications/${id}/read`, {
    method: 'PATCH',
    headers: authHeaders(token),
  });
  if (!res.ok) throw new Error('Failed to mark notification as read');
}

export async function deleteNotification(token: string, id: string): Promise<void> {
  const res = await fetch(`${API_BASE}/api/notifications/${id}`, {
    method: 'DELETE',
    headers: authHeaders(token),
  });
  if (!res.ok) throw new Error('Failed to delete notification');
}

// ─── Project Shares ──────────────────────────────────────
export interface ProjectShare {
  id: string;
  project_id: string;
  shared_with_email: string;
  shared_by: string;
  permission: string;
  share_token: string | null;
  created_at: string;
}

export async function getProjectShares(token: string, projectId: string): Promise<ProjectShare[]> {
  const res = await fetch(`${API_BASE}/api/projects/${projectId}/shares`, { headers: authHeaders(token) });
  if (!res.ok) throw new Error('Failed to load shares');
  return res.json();
}

export async function createProjectShare(token: string, projectId: string, data: { shared_with_email: string; permission?: string }): Promise<ProjectShare> {
  const res = await fetch(`${API_BASE}/api/projects/${projectId}/shares`, {
    method: 'POST',
    headers: { ...authHeaders(token), 'Content-Type': 'application/json' },
    body: JSON.stringify(data),
  });
  if (!res.ok) throw new Error('Failed to create share');
  return res.json();
}

export async function deleteProjectShare(token: string, shareId: string): Promise<void> {
  const res = await fetch(`${API_BASE}/api/shares/${shareId}`, {
    method: 'DELETE',
    headers: authHeaders(token),
  });
  if (!res.ok) throw new Error('Failed to delete share');
}

export { API_BASE };

// ─── AI Copilot ─────────────────────────────────────────
export interface AIChatMessage {
  role: string;
  content: string;
}

export interface AIChatContext {
  projectName?: string;
  elementCount?: number;
  layerCount?: number;
  elementTypeSummary?: Record<string, number>;
}

export async function aiChat(
  token: string,
  messages: AIChatMessage[],
  context?: AIChatContext
): Promise<{ content: string; suggestions?: string[] }> {
  const res = await fetch(`${API_BASE}/api/ai/chat`, {
    method: 'POST',
    headers: authHeaders(token),
    body: JSON.stringify({ messages, context }),
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({ error: 'AI request failed' }));
    throw new Error(err.error || 'AI request failed');
  }
  return res.json();
}