// Analyzer Service — streams API spec analysis via Claude

import Anthropic from '@anthropic-ai/sdk';
import { getSkill } from '../skills/loader';
import { parseStreamEvents } from '../streaming/parser';
import type {
  PipelineEvent,
  AnalysisResult,
  ToolDefinition,
} from '../types';

const MODEL = 'claude-sonnet-4-5-20250514';
const MAX_TOKENS = 8192;

/**
 * Analyze an API spec (OpenAPI/Swagger JSON or YAML string).
 * Streams PipelineEvent objects as analysis progresses.
 */
export async function* analyzeSpec(spec: string): AsyncGenerator<PipelineEvent> {
  const client = new Anthropic({ apiKey: process.env.ANTHROPIC_API_KEY });
  const systemPrompt = getSkill('analyzer');

  yield { type: 'analysis:progress', step: 'Starting API analysis', percent: 0 };

  try {
    const stream = client.messages.stream({
      model: MODEL,
      max_tokens: MAX_TOKENS,
      system: systemPrompt,
      messages: [
        {
          role: 'user',
          content: `Analyze this API specification and produce a complete MCP tool mapping.\n\nReturn your analysis as a JSON object with this structure:\n{\n  "service": "service name",\n  "baseUrl": "base URL",\n  "endpoints": [...],\n  "authFlow": { "type": "api_key|oauth2|bearer|basic|custom", ... },\n  "toolGroups": [{ "name": "...", "description": "...", "tools": [...] }],\n  "appCandidates": [{ "name": "...", "pattern": "...", "description": "...", "dataSource": [...], "suggestedWidgets": [...] }],\n  "rateLimits": { ... }\n}\n\nWrap the final JSON in a \`\`\`json code block.\n\nAPI Specification:\n\`\`\`\n${spec}\n\`\`\``,
        },
      ],
    });

    let fullText = '';
    let lastPercent = 0;

    stream.on('text', (text) => {
      fullText += text;
    });

    // Process the stream
    for await (const event of stream) {
      if (event.type === 'content_block_delta' && event.delta.type === 'text_delta') {
        const newPercent = Math.min(90, Math.floor((fullText.length / 4000) * 90));
        if (newPercent > lastPercent + 5) {
          lastPercent = newPercent;
          yield { type: 'analysis:progress', step: 'Analyzing endpoints and generating tools', percent: newPercent };
        }

        // Check for tool definitions appearing in stream
        const toolEvents = parseStreamEvents(fullText, 'analysis');
        for (const te of toolEvents) {
          if (te.type === 'analysis:tool_found') {
            yield te;
          }
        }
      }
    }

    // Get final message for token usage
    const finalMessage = await stream.finalMessage();
    const usage = {
      inputTokens: finalMessage.usage.input_tokens,
      outputTokens: finalMessage.usage.output_tokens,
    };

    yield { type: 'analysis:progress', step: 'Parsing analysis results', percent: 95 };

    // Extract JSON from the full response
    const result = extractAnalysisResult(fullText);

    if (result) {
      // Yield individual tools as they're found
      for (const group of result.toolGroups) {
        for (const tool of group.tools) {
          yield { type: 'analysis:tool_found', tool: tool as ToolDefinition };
        }
      }

      yield { type: 'analysis:complete', result };
    } else {
      yield {
        type: 'error',
        message: 'Failed to parse analysis result from Claude response',
        recoverable: true,
      };
    }
  } catch (error) {
    const msg = error instanceof Error ? error.message : String(error);
    yield {
      type: 'error',
      message: `Analysis failed: ${msg}`,
      recoverable: error instanceof Anthropic.RateLimitError,
    };
  }
}

function extractAnalysisResult(text: string): AnalysisResult | null {
  // Try to find JSON in code blocks
  const jsonMatch = text.match(/```json\s*\n([\s\S]*?)\n```/);
  if (jsonMatch) {
    try {
      const parsed = JSON.parse(jsonMatch[1]);
      return {
        id: crypto.randomUUID(),
        service: parsed.service || 'unknown',
        baseUrl: parsed.baseUrl || '',
        endpoints: parsed.endpoints || [],
        authFlow: parsed.authFlow || { type: 'api_key' },
        toolGroups: parsed.toolGroups || [],
        appCandidates: parsed.appCandidates || [],
        rateLimits: parsed.rateLimits || {},
      };
    } catch {
      // fall through
    }
  }

  // Try raw JSON parse
  const braceStart = text.indexOf('{');
  const braceEnd = text.lastIndexOf('}');
  if (braceStart !== -1 && braceEnd > braceStart) {
    try {
      const parsed = JSON.parse(text.slice(braceStart, braceEnd + 1));
      return {
        id: crypto.randomUUID(),
        service: parsed.service || 'unknown',
        baseUrl: parsed.baseUrl || '',
        endpoints: parsed.endpoints || [],
        authFlow: parsed.authFlow || { type: 'api_key' },
        toolGroups: parsed.toolGroups || [],
        appCandidates: parsed.appCandidates || [],
        rateLimits: parsed.rateLimits || {},
      };
    } catch {
      return null;
    }
  }

  return null;
}