import {
  BaseProvider,
  GatewayChatContentBlock,
  GatewayChatMessage,
  GatewayToolChoice,
  GatewayToolDefinition,
  GatewayToolResultContentBlock,
  ProviderCapabilities,
  ProviderStreamChunk,
  ToolCapableChatOptions,
} from "./BaseProvider";

import OpenAI from "openai";
import logManager from "@electron/service/logger"

const OPENAI_PROVIDER_CAPABILITIES: ProviderCapabilities = {
  structuredMessages: true,
  toolCalls: true,
  toolResults: true,
  thinking: false,
};

function _flattenContent(content: string | GatewayChatContentBlock[] | undefined): string {
  if (typeof content === 'string') {
    return content;
  }

  if (!Array.isArray(content)) {
    return '';
  }

  return content
    .map((block) => {
      if (!block || typeof block !== 'object') {
        return '';
      }

      if (block.type === 'text' && typeof block.text === 'string') {
        return block.text;
      }

      if (block.type === 'thinking' && typeof block.thinking === 'string') {
        return block.thinking;
      }

      if (block.type === 'tool_result') {
        return _flattenContent(block.content);
      }

      return '';
    })
    .filter(Boolean)
    .join('\n');
}

function _extractToolCalls(content: GatewayChatContentBlock[]): Array<Record<string, unknown>> | undefined {
  const toolCalls = content
    .flatMap((block, index) => {
      if (block.type !== 'tool_use' || !block.name) {
        return [];
      }

      return [{
        id: block.id || `tool_call_${index}`,
        type: 'function',
        function: {
          name: block.name,
          arguments: JSON.stringify(block.input ?? {}),
        },
      }];
    });

  return toolCalls.length ? toolCalls : undefined;
}

function _findToolResultBlock(
  content: GatewayChatMessage['content']
): GatewayToolResultContentBlock | undefined {
  if (!Array.isArray(content)) {
    return undefined;
  }

  return content.find(
    (block): block is GatewayToolResultContentBlock => block.type === 'tool_result'
  );
}

function _transformMessage(message: GatewayChatMessage): Record<string, unknown> | null {
  const normalizedRole = message.role === 'toolresult' || message.role === 'tool_result'
    ? 'tool'
    : message.role;

  if (normalizedRole === 'assistant') {
    const content = Array.isArray(message.content) ? message.content : undefined;
    const toolCalls = content ? _extractToolCalls(content) : undefined;
    const text = _flattenContent(message.content).trim();

    if (!text && !toolCalls?.length) {
      return null;
    }

    return {
      role: 'assistant',
      content: text || null,
      ...(toolCalls?.length ? { tool_calls: toolCalls } : {}),
    };
  }

  if (normalizedRole === 'tool') {
    const resultBlock = _findToolResultBlock(message.content);
    const toolCallId = message.toolCallId || resultBlock?.toolCallId;
    const text = _flattenContent(resultBlock?.content ?? message.content).trim();

    return {
      role: 'tool',
      tool_call_id: toolCallId || `${message.name || 'tool'}_call`,
      content: text || resultBlock?.summary || 'Tool result',
    };
  }

  const text = _flattenContent(message.content).trim();
  if (!text) {
    return null;
  }

  return {
    role: normalizedRole,
    content: text,
  };
}

function _transformMessages(messages: GatewayChatMessage[]): Array<Record<string, unknown>> {
  return messages
    .map((message) => _transformMessage(message))
    .filter((message): message is Record<string, unknown> => message !== null);
}

function _normalizeToolSchema(inputSchema: unknown): Record<string, unknown> {
  if (inputSchema && typeof inputSchema === 'object' && !Array.isArray(inputSchema)) {
    return inputSchema as Record<string, unknown>;
  }

  return {
    type: 'object',
    properties: {},
    additionalProperties: true,
  };
}

function _transformTools(tools?: GatewayToolDefinition[]): Array<Record<string, unknown>> | undefined {
  if (!tools?.length) {
    return undefined;
  }

  return tools.map((tool) => ({
    type: 'function',
    function: {
      name: tool.name,
      ...(tool.description ? { description: tool.description } : {}),
      parameters: _normalizeToolSchema(tool.inputSchema),
    },
  }));
}

function _transformToolChoice(choice?: GatewayToolChoice): string | Record<string, unknown> | undefined {
  if (!choice) {
    return undefined;
  }

  if (typeof choice === 'string') {
    return choice;
  }

  return {
    type: 'function',
    function: {
      name: choice.name,
    },
  };
}

function _summarizeMessage(message?: GatewayChatMessage): string {
  if (!message) {
    return '';
  }

  return _flattenContent(message.content);
}

function _transformChunk(chunk: OpenAI.Chat.Completions.ChatCompletionChunk): ProviderStreamChunk {
  const choice = chunk.choices[0];
  const usage = (chunk as any).usage;
  const delta = choice?.delta as any;
  const result = delta?.content ?? '';
  const toolCalls = Array.isArray(delta?.tool_calls)
    ? delta.tool_calls.map((toolCall: any) => ({
      index: typeof toolCall?.index === 'number' ? toolCall.index : undefined,
      id: typeof toolCall?.id === 'string' ? toolCall.id : undefined,
      name: typeof toolCall?.function?.name === 'string' ? toolCall.function.name : undefined,
      argumentsDelta:
        typeof toolCall?.function?.arguments === 'string'
          ? toolCall.function.arguments
          : undefined,
      raw: toolCall,
    }))
    : undefined;

  return {
    isEnd: choice?.finish_reason != null || (chunk.choices.length === 0 && usage != null),
    result,
    usage: usage ?? undefined,
    content: result ? [{ type: 'text', text: result }] : undefined,
    toolCalls: toolCalls?.length ? toolCalls : undefined,
    finishReason: choice?.finish_reason ?? null,
    raw: chunk,
  }
}

export class OpenAIProvider extends BaseProvider {
  private client: OpenAI;

  constructor(apiKey: string, baseURL: string, headers?: Record<string, string>) {
    super();
    this.client = new OpenAI({ apiKey, baseURL, defaultHeaders: headers });
  }

  getCapabilities(): ProviderCapabilities {
    return OPENAI_PROVIDER_CAPABILITIES;
  }

  async chat(
    messages: GatewayChatMessage[],
    model: string,
    options?: ToolCapableChatOptions
  ): Promise<AsyncIterable<ProviderStreamChunk>> {
    const startTime = Date.now();
    const transformedMessages = _transformMessages(messages);
    const tools = _transformTools(options?.tools);
    const toolChoice = tools?.length ? _transformToolChoice(options?.toolChoice) : undefined;
    const lastMessage = messages[messages.length - 1];

    logManager.logApiRequest('chat.completions.create', {
      model,
      lastMessage: _summarizeMessage(lastMessage).substring(0, 100)
        + (_summarizeMessage(lastMessage).length > 100 ? '...' : ''),
      messageCount: transformedMessages.length,
      toolCount: tools?.length ?? 0,
      toolChoice: typeof toolChoice === 'string' ? toolChoice : (toolChoice ? 'named' : undefined),
    }, 'POST');

    try {
      const request: Record<string, unknown> = {
        model,
        messages: transformedMessages,
        stream: true,
        stream_options: { include_usage: true },
      };

      if (tools?.length) {
        request.tools = tools;
      }

      if (toolChoice) {
        request.tool_choice = toolChoice;
      }

      const chunks = await this.client.chat.completions.create(request as any, {
        signal: options?.signal,
      });

      return {
        async *[Symbol.asyncIterator]() {
          try {
            for await (const chunk of chunks) {
              if (options?.signal?.aborted) break;
              yield _transformChunk(chunk);
            }
            const responseTime = Date.now() - startTime;
            logManager.logApiResponse('chat.completions.create', { success: true }, 200, responseTime);
          } catch (error) {
            const responseTime = Date.now() - startTime;
            logManager.logApiResponse('chat.completions.create', { error: error instanceof Error ? error.message : String(error) }, 500, responseTime);
            throw error;
          }
        }
      }
    } catch (error) {
      const responseTime = Date.now() - startTime;
      logManager.logApiResponse('chat.completions.create', { error: error instanceof Error ? error.message : String(error) }, 500, responseTime);
      throw error;
    }
  }
}