import * as vscode from 'vscode';
import { getConfig } from '../config';
import { AgentExecuteOptions } from '../lib/engine';

export abstract class BaseAgent {
    constructor(protected readonly modelName: string) {}

    protected async callLLM(persona: string, prompt: string, signal?: AbortSignal): Promise<string> {
        const { ollamaUrl } = getConfig();
        if (!ollamaUrl) {
            throw new Error('Ollama URL이 설정되지 않았습니다. 설정을 확인해주세요.');
        }

        if (typeof fetch === 'undefined') {
            throw new Error('이 환경에서는 fetch 함수를 사용할 수 없습니다. Node.js 버전을 확인하거나 polyfill이 필요합니다.');
        }

        const messages = [
            { role: 'system', content: persona },
            { role: 'user', content: prompt }
        ];

        // 엔진 자동 감지 (Ollama vs OpenAI/LM Studio)
        const isOllama = ollamaUrl.includes(':11434') || ollamaUrl.includes('ollama');
        const endpoint = isOllama ? `${ollamaUrl}/api/chat` : `${ollamaUrl}/v1/chat/completions`;

        // 컨텍스트 초과 방지를 위해 출력 토큰 상한을 항상 명시한다 (서브에이전트 중간 산출물용).
        const { contextLength, maxOutputTokens } = getConfig();
        const numCtx = Math.max(2048, contextLength);
        const outCap = Math.max(256, maxOutputTokens);

        let lastError: any;
        for (let attempt = 1; attempt <= 3; attempt++) {
            const controller = new AbortController();
            const timeoutId = setTimeout(() => controller.abort(), 45000);
            const combinedSignal = signal ? anySignal([signal, controller.signal]) : controller.signal;

            try {
                if (attempt > 1) await new Promise(resolve => setTimeout(resolve, 1000 * attempt));

            const response = await fetch(endpoint, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify(isOllama ? {
                    model: this.modelName,
                    messages,
                    stream: false,
                    options: { temperature: 0.3, num_ctx: numCtx, num_predict: outCap }
                } : {
                    model: this.modelName,
                    messages,
                    stream: false,
                    temperature: 0.3,
                    max_tokens: outCap
                }),
                signal: combinedSignal
            });

            clearTimeout(timeoutId);

            if (!response.ok) {
                throw new Error(`Agent API Error: ${response.statusText} (${response.status})`);
            }

                const data = await response.json() as any;
                
                // 강력한 응답 추출 (Multi-path parsing)
                let content = '';
                if (data.message?.content) content = data.message.content;
                else if (data.choices?.[0]?.message?.content) content = data.choices[0].message.content;
                else if (data.choices?.[0]?.text) content = data.choices[0].text;
                else if (data.response) content = data.response;
                else if (typeof data === 'string') content = data;
                
                return content || '';
            } catch (error: any) {
                clearTimeout(timeoutId);
                lastError = error;
                if (error.name === 'AbortError') break;
                if (attempt === 3) break;
            }
        }
        throw lastError;
    }

    abstract execute(input: string, context?: string, signal?: AbortSignal, options?: AgentExecuteOptions): Promise<string>;
}

// Helper to combine signals (since AbortSignal.any is not always available in older Node)
function anySignal(signals: AbortSignal[]): AbortSignal {
    const controller = new AbortController();
    for (const signal of signals) {
        if (signal.aborted) {
            controller.abort();
            return signal;
        }
        signal.addEventListener('abort', () => controller.abort(), { once: true });
    }
    return controller.signal;
}

export class PlannerAgent extends BaseAgent {
    private readonly persona = `You are the [Master Strategist & Planner]. 
Your sole purpose is to transform vague requests into flawless, high-resolution execution blueprints.
- THINKING PROCESS: You must analyze the request from multiple angles (technical, logical, structural).
- OUTPUT RULE: You MUST output a structured <blueprint> using Markdown.
- COMPONENTS: Each blueprint must have [Objective], [Core Challenges], [Data Requirements], and [Step-by-Step Research Tasks].
- CONSTRAINT: Do not be vague. Use professional terminology. If the request is too simple, expand it with relevant technical considerations.`;

    async execute(input: string, brainContext?: string, signal?: AbortSignal, options?: AgentExecuteOptions): Promise<string> {
        const wrappedInput = `### SYSTEM INSTRUCTION: GENERATE EXECUTION BLUEPRINT
1. Target Goal: ${input}
2. Available Knowledge Base & Policy: ${brainContext}
3. Mission: Create a comprehensive research roadmap.`;
        return this.callLLM(this.persona, wrappedInput, signal);
    }
}

export class ResearcherAgent extends BaseAgent {
    private readonly persona = `You are the [Senior Technical Researcher]. 
Your mission is to extract, filter, and synthesize critical data based on a strategic blueprint.
- DATA INTEGRITY: Only provide high-quality, verified-style information. 
- FORMAT: Use [Key Facts], [Technical Deep-Dive], and [Summary of Knowledge] sections.
- CRITICAL THINKING: Identify gaps in the plan and provide extra insights to fill those gaps.
- NO FLUFF: Be concise but extremely dense with information.`;

    async execute(input: string, brainContext?: string, signal?: AbortSignal, options?: AgentExecuteOptions): Promise<string> {
        const wrappedInput = `### SYSTEM INSTRUCTION: DATA HARVESTING
1. Blueprint to Follow: ${input}
2. Contextual Constraints & Policy: ${brainContext}
3. Mission: Provide a dense summary of facts and technical insights.`;
        return this.callLLM(this.persona, wrappedInput, signal);
    }
}

export class WriterAgent extends BaseAgent {
    private readonly persona = `You are the [Lead Synthesis Writer & Editor]. 
Your goal is to produce a state-of-the-art final report that wows the user.
- TONE: Authoritative yet accessible. Professional developer/consultant style.
- STRUCTURE: Use an executive summary, detailed analysis sections, and a "Final Recommendation" block.
- LANGUAGE: Always respond in the user's language (KOREAN).
- POLISHING: Ensure logical flow between sections. Make it look like a premium report.`;

    async execute(input: string, originalRequest?: string, signal?: AbortSignal, options?: AgentExecuteOptions): Promise<string> {
        // [Astra v4.0] Advisor 모드 처리
        if (options?.config?.role === 'advisor') {
            const advisorPersona = `You are the [Strategic Proactive Advisor].
Analyze the provided report and suggest 3 high-impact next actions for the user.
- Focus on decision forks, risk mitigation, or immediate implementation steps.
- Be extremely concrete and actionable.
- Respond in KOREAN.`;
            return this.callLLM(advisorPersona, input, signal);
        }

        // Fix 3: Trim input if it's too long (Basic Context Diet)
        const trimmedData = input.length > 8000 ? input.substring(0, 8000) + '... [Data Trimmed for Performance]' : input;
        
        const policy = options?.context || '';
        const wrappedInput = `### SYSTEM INSTRUCTION: FINAL SYNTHESIS
1. Gathered Research Data: ${trimmedData}
2. User's Original Objective: ${originalRequest}
3. Applied Knowledge & Filtering Policy: ${policy}
4. Mission: Write the definitive final report in KOREAN.`;
        return this.callLLM(this.persona, wrappedInput, signal);
    }
}