/**
 * LiteLLM API Config Manager
 * Manages provider credentials, endpoint configurations, and model discovery
 */

import { join } from 'path';
import { readFileSync, writeFileSync, existsSync, mkdirSync } from 'fs';
import { homedir } from 'os';

// ===========================
// Type Definitions
// ===========================

export type ProviderType =
  | 'openai'
  | 'anthropic'
  | 'google'
  | 'cohere'
  | 'azure'
  | 'bedrock'
  | 'vertexai'
  | 'huggingface'
  | 'ollama'
  | 'custom';

export interface ProviderCredential {
  id: string;
  name: string;
  type: ProviderType;
  apiKey?: string;
  baseUrl?: string;
  apiVersion?: string;
  region?: string;
  projectId?: string;
  organizationId?: string;
  enabled: boolean;
  metadata?: Record<string, any>;
  createdAt: string;
  updatedAt: string;
}

export interface EndpointConfig {
  id: string;
  name: string;
  providerId: string;
  model: string;
  alias?: string;
  temperature?: number;
  maxTokens?: number;
  topP?: number;
  enabled: boolean;
  metadata?: Record<string, any>;
  createdAt: string;
  updatedAt: string;
}

export interface ModelInfo {
  id: string;
  name: string;
  provider: ProviderType;
  contextWindow: number;
  supportsFunctions: boolean;
  supportsStreaming: boolean;
  inputCostPer1k?: number;
  outputCostPer1k?: number;
}

export interface LiteLLMApiConfig {
  version: string;
  providers: ProviderCredential[];
  endpoints: EndpointConfig[];
}

// ===========================
// Model Definitions
// ===========================

export const PROVIDER_MODELS: Record<ProviderType, ModelInfo[]> = {
  openai: [
    {
      id: 'gpt-4-turbo',
      name: 'GPT-4 Turbo',
      provider: 'openai',
      contextWindow: 128000,
      supportsFunctions: true,
      supportsStreaming: true,
      inputCostPer1k: 0.01,
      outputCostPer1k: 0.03,
    },
    {
      id: 'gpt-4',
      name: 'GPT-4',
      provider: 'openai',
      contextWindow: 8192,
      supportsFunctions: true,
      supportsStreaming: true,
      inputCostPer1k: 0.03,
      outputCostPer1k: 0.06,
    },
    {
      id: 'gpt-3.5-turbo',
      name: 'GPT-3.5 Turbo',
      provider: 'openai',
      contextWindow: 16385,
      supportsFunctions: true,
      supportsStreaming: true,
      inputCostPer1k: 0.0005,
      outputCostPer1k: 0.0015,
    },
  ],
  anthropic: [
    {
      id: 'claude-3-opus-20240229',
      name: 'Claude 3 Opus',
      provider: 'anthropic',
      contextWindow: 200000,
      supportsFunctions: true,
      supportsStreaming: true,
      inputCostPer1k: 0.015,
      outputCostPer1k: 0.075,
    },
    {
      id: 'claude-3-sonnet-20240229',
      name: 'Claude 3 Sonnet',
      provider: 'anthropic',
      contextWindow: 200000,
      supportsFunctions: true,
      supportsStreaming: true,
      inputCostPer1k: 0.003,
      outputCostPer1k: 0.015,
    },
    {
      id: 'claude-3-haiku-20240307',
      name: 'Claude 3 Haiku',
      provider: 'anthropic',
      contextWindow: 200000,
      supportsFunctions: true,
      supportsStreaming: true,
      inputCostPer1k: 0.00025,
      outputCostPer1k: 0.00125,
    },
  ],
  google: [
    {
      id: 'gemini-pro',
      name: 'Gemini Pro',
      provider: 'google',
      contextWindow: 32768,
      supportsFunctions: true,
      supportsStreaming: true,
    },
    {
      id: 'gemini-pro-vision',
      name: 'Gemini Pro Vision',
      provider: 'google',
      contextWindow: 16384,
      supportsFunctions: false,
      supportsStreaming: true,
    },
  ],
  cohere: [
    {
      id: 'command',
      name: 'Command',
      provider: 'cohere',
      contextWindow: 4096,
      supportsFunctions: false,
      supportsStreaming: true,
    },
    {
      id: 'command-light',
      name: 'Command Light',
      provider: 'cohere',
      contextWindow: 4096,
      supportsFunctions: false,
      supportsStreaming: true,
    },
  ],
  azure: [],
  bedrock: [],
  vertexai: [],
  huggingface: [],
  ollama: [],
  custom: [],
};

// ===========================
// Config File Management
// ===========================

const CONFIG_DIR = join(homedir(), '.claude', 'litellm');
const CONFIG_FILE = join(CONFIG_DIR, 'config.json');

function ensureConfigDir(): void {
  if (!existsSync(CONFIG_DIR)) {
    mkdirSync(CONFIG_DIR, { recursive: true });
  }
}

function loadConfig(): LiteLLMApiConfig {
  ensureConfigDir();

  if (!existsSync(CONFIG_FILE)) {
    const defaultConfig: LiteLLMApiConfig = {
      version: '1.0.0',
      providers: [],
      endpoints: [],
    };
    saveConfig(defaultConfig);
    return defaultConfig;
  }

  try {
    const content = readFileSync(CONFIG_FILE, 'utf-8');
    return JSON.parse(content);
  } catch (err) {
    throw new Error(`Failed to load config: ${(err as Error).message}`);
  }
}

function saveConfig(config: LiteLLMApiConfig): void {
  ensureConfigDir();

  try {
    writeFileSync(CONFIG_FILE, JSON.stringify(config, null, 2), 'utf-8');
  } catch (err) {
    throw new Error(`Failed to save config: ${(err as Error).message}`);
  }
}

// ===========================
// Provider Management
// ===========================

export function getAllProviders(): ProviderCredential[] {
  const config = loadConfig();
  return config.providers;
}

export function getProvider(id: string): ProviderCredential | null {
  const config = loadConfig();
  return config.providers.find((p) => p.id === id) || null;
}

export function createProvider(
  data: Omit<ProviderCredential, 'id' | 'createdAt' | 'updatedAt'>
): ProviderCredential {
  const config = loadConfig();

  const now = new Date().toISOString();
  const provider: ProviderCredential = {
    ...data,
    id: `provider-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
    createdAt: now,
    updatedAt: now,
  };

  config.providers.push(provider);
  saveConfig(config);

  return provider;
}

export function updateProvider(
  id: string,
  updates: Partial<ProviderCredential>
): ProviderCredential | null {
  const config = loadConfig();

  const index = config.providers.findIndex((p) => p.id === id);
  if (index === -1) {
    return null;
  }

  const updated: ProviderCredential = {
    ...config.providers[index],
    ...updates,
    id,
    updatedAt: new Date().toISOString(),
  };

  config.providers[index] = updated;
  saveConfig(config);

  return updated;
}

export function deleteProvider(id: string): { success: boolean } {
  const config = loadConfig();

  const index = config.providers.findIndex((p) => p.id === id);
  if (index === -1) {
    return { success: false };
  }

  config.providers.splice(index, 1);

  // Also delete endpoints using this provider
  config.endpoints = config.endpoints.filter((e) => e.providerId !== id);

  saveConfig(config);

  return { success: true };
}

export async function testProviderConnection(
  providerId: string
): Promise<{ success: boolean; error?: string }> {
  const provider = getProvider(providerId);

  if (!provider) {
    return { success: false, error: 'Provider not found' };
  }

  if (!provider.enabled) {
    return { success: false, error: 'Provider is disabled' };
  }

  // Basic validation
  if (!provider.apiKey && provider.type !== 'ollama' && provider.type !== 'custom') {
    return { success: false, error: 'API key is required for this provider type' };
  }

  // TODO: Implement actual provider connection testing using litellm-client
  // For now, just validate the configuration
  return { success: true };
}

// ===========================
// Endpoint Management
// ===========================

export function getAllEndpoints(): EndpointConfig[] {
  const config = loadConfig();
  return config.endpoints;
}

export function getEndpoint(id: string): EndpointConfig | null {
  const config = loadConfig();
  return config.endpoints.find((e) => e.id === id) || null;
}

export function createEndpoint(
  data: Omit<EndpointConfig, 'id' | 'createdAt' | 'updatedAt'>
): EndpointConfig {
  const config = loadConfig();

  // Validate provider exists
  const provider = config.providers.find((p) => p.id === data.providerId);
  if (!provider) {
    throw new Error('Provider not found');
  }

  const now = new Date().toISOString();
  const endpoint: EndpointConfig = {
    ...data,
    id: `endpoint-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
    createdAt: now,
    updatedAt: now,
  };

  config.endpoints.push(endpoint);
  saveConfig(config);

  return endpoint;
}

export function updateEndpoint(
  id: string,
  updates: Partial<EndpointConfig>
): EndpointConfig | null {
  const config = loadConfig();

  const index = config.endpoints.findIndex((e) => e.id === id);
  if (index === -1) {
    return null;
  }

  // Validate provider if being updated
  if (updates.providerId) {
    const provider = config.providers.find((p) => p.id === updates.providerId);
    if (!provider) {
      throw new Error('Provider not found');
    }
  }

  const updated: EndpointConfig = {
    ...config.endpoints[index],
    ...updates,
    id,
    updatedAt: new Date().toISOString(),
  };

  config.endpoints[index] = updated;
  saveConfig(config);

  return updated;
}

export function deleteEndpoint(id: string): { success: boolean } {
  const config = loadConfig();

  const index = config.endpoints.findIndex((e) => e.id === id);
  if (index === -1) {
    return { success: false };
  }

  config.endpoints.splice(index, 1);
  saveConfig(config);

  return { success: true };
}

// ===========================
// Model Discovery
// ===========================

export function getModelsForProviderType(providerType: ProviderType): ModelInfo[] | null {
  return PROVIDER_MODELS[providerType] || null;
}

export function getAllModels(): Record<ProviderType, ModelInfo[]> {
  return PROVIDER_MODELS;
}

// ===========================
// Config Access
// ===========================

export function getFullConfig(): LiteLLMApiConfig {
  return loadConfig();
}

export function resetConfig(): void {
  const defaultConfig: LiteLLMApiConfig = {
    version: '1.0.0',
    providers: [],
    endpoints: [],
  };
  saveConfig(defaultConfig);
}