/**
 * Tesla Roadtrip — Grok Headless Client
 *
 * Now using pure JSON output mode for much more reliable structured itineraries.
 */
import { spawn } from 'child_process';
import { mkdtemp, rm, access } from 'fs/promises';
import { tmpdir } from 'os';
import { join } from 'path';
import { createLogger } from '../../lib/logger.js';
import { env } from '../../config/env.js';
import crypto from 'crypto';

const log = createLogger('grok-headless');
const SENTINEL = 'ITINERARY_UPDATE:';

export interface ChatMessage { role: 'user' | 'assistant' | 'system'; content: string; }
export interface GrokResponse { text: string; updatedItinerary?: any; }
export type VehicleInput = string | { name: string; rangeKm?: number };

function vehicleName(v: VehicleInput): string {
  return typeof v === 'string' ? v : v.name;
}

type Provider = 'local' | 'xai' | 'fallback';

export class GrokHeadlessClient {
  private provider: Provider;

  constructor() {
    this.provider = this.resolveInitialProvider();
    log.info({ provider: this.provider, grokBin: env.grokBin, forceXaiApi: env.forceXaiApi }, 'GrokHeadlessClient initialized');
  }

  private resolveInitialProvider(): Provider {
    if (env.forceXaiApi && env.xaiApiKey) return 'xai';
    if (!env.grokEnabled) return env.xaiApiKey ? 'xai' : 'fallback';
    return 'local';
  }

  private async getActiveProvider(requestId: string): Promise<Provider> {
    if (env.forceXaiApi) {
      if (env.xaiApiKey) {
        log.info({ requestId }, 'Provider decision: xAI API (FORCE_XAI_API=true)');
        return 'xai';
      }
      return 'fallback';
    }
    if (!env.grokEnabled) {
      return env.xaiApiKey ? 'xai' : 'fallback';
    }
    try {
      await access(env.grokBin);
      log.info({ requestId, bin: env.grokBin }, 'Provider decision: LOCAL personal Grok CLI (your authenticated Heavy account)');
      return 'local';
    } catch {
      log.info({ requestId, bin: env.grokBin }, 'Local grok binary not found — using xAI API');
      return env.xaiApiKey ? 'xai' : 'fallback';
    }
  }

  private buildPrompt(messages: ChatMessage[], itinerary: any, vehicle: VehicleInput) {
    return `You are Grok Drive, an expert Tesla road trip planner for the UK and Europe. You build practical, enjoyable itineraries — not just a list of charging stops. Treat every break as a chance to eat, rest, sightsee, or sleep.

Current vehicle: ${vehicleName(vehicle)}
Current itinerary: ${JSON.stringify(itinerary || {}, null, 2)}

Respond with **only** a single valid JSON object in exactly this format. No text before or after. No markdown.

{
  "message": "A friendly, natural reply to the user (1-4 sentences). Highlight one or two of the best combo picks (e.g. 'I picked the Watford Gap Supercharger because the M&S Food Hall is right there').",
  "itinerary": {
    "days": [
      {
        "day": 1,
        "title": "Short day label like 'London → Manchester'",
        "stops": [
          {
            "id": "unique-string",
            "name": "Human readable name",
            "type": "supercharger" | "destination-charger" | "hotel" | "attraction" | "restaurant" | "cafe" | "viewpoint" | "custom",
            "lat": 51.477,
            "lng": -0.17,
            "day": 1,
            "order": 1,
            "estArrivalBattery": 25,
            "chargeMinutes": 25,
            "durationMin": 45,
            "combo": "charge + eat" | "charge + coffee" | "stay + destination charging" | "eat + viewpoint" | "charge + shopping" | null,
            "description": "1-2 sentence reason this stop is a great pick — what's right next to the charger, why this hotel, what's special about this stop",
            "amenities": ["restaurant", "coffee", "toilets", "shopping", "wifi", "playground", "ev-charging", "destination-charging"],
            "cuisine": "British pub" | "Italian" | "French" | "Cafe" | null,
            "priceLevel": 1 | 2 | 3 | 4,
            "notes": "optional extra hint (booking tips, opening hours, etc.)",
            "alternatives": [
              {
                "id": "unique-alt-string",
                "name": "Alternative pick name",
                "type": "supercharger" | "hotel" | "restaurant" | "cafe" | "attraction" | "destination-charger" | "viewpoint" | "custom",
                "lat": 51.5,
                "lng": -0.1,
                "description": "1-2 sentences explaining why this is a viable swap",
                "combo": "charge + eat" | "stay + destination charging" | null,
                "amenities": ["restaurant", "toilets"],
                "cuisine": "Italian" | null,
                "priceLevel": 2,
                "chargeMinutes": 25,
                "durationMin": 60,
                "deltaKm": 12,
                "deltaMin": 9,
                "reason": "Short reason this is a worthwhile alternative (e.g. 'Cheaper and faster but no restaurant on site')"
              }
            ]
          }
        ]
      }
    ],
    "summary": {
      "totalDistanceKm": 650,
      "estDriveHours": 10.5,
      "estChargeHours": 1.5,
      "superchargers": 3,
      "hotels": 1,
      "highlights": ["Lunch at Tebay services", "Sunset view at Crummock Water"]
    }
  }
}

Strict route planning rules:
- Plan stops in the actual order the driver will encounter them on the road.
- Choose Superchargers that are realistically reachable given the vehicle range.
- Space charging stops sensibly (every 150-250km depending on route and battery).
- Calculate realistic estArrivalBattery based on distance driven since last charge.
- Every stop MUST have accurate real-world latitude and longitude.
- Use realistic daily driving distances (max ~5-6 hours driving per day).
- "message" should feel like a helpful human assistant.
- If no clear trip is requested yet, set "itinerary" to null.

Alternatives (REQUIRED for every Supercharger and hotel stop):
- For each Supercharger or hotel stop, populate "alternatives" with 1-3 realistic swap options the driver might prefer.
- Each alternative is a fully-formed stop the user could swap to: complete lat/lng, type, name, description.
- "deltaKm" is the estimated change in total trip distance vs the chosen stop (positive = adds km, negative = saves km).
- "deltaMin" is the estimated change in total drive time vs the chosen stop, in minutes.
- "reason" explains the trade-off in one short sentence ("Cheaper hotel, no destination charging" / "Adds 15 mins but has the best food on this stretch of the M6").
- Alternatives must be genuinely different choices a driver would consider — not minor variants. Mix the trade-offs: faster, cheaper, fancier, better food, closer to attractions, etc.
- For non-Supercharger/non-hotel stops (a viewpoint, a quick coffee), alternatives are optional.

Combo philosophy (THIS IS THE IMPORTANT PART — don't skip):
- Whenever possible, pick Superchargers that are co-located with a real restaurant, cafe, services area, supermarket, or visitor attraction. Mention what's there in "description" and tag the stop with combo: "charge + eat" (or similar).
- Prefer hotels that offer destination charging (Tesla destination chargers, Type 2, or onsite EV charging). Tag those combo: "stay + destination charging" and add "destination-charging" to amenities.
- For meal-time stops, look for a charger close to a great independent restaurant or cafe — not just "the Supercharger has a McDonald's next door" unless that's all there is.
- If a stop is just a quick top-up with nothing nearby, that's fine — set combo to null and explain in description.
- Use "durationMin" to indicate the total time at that stop (charge time + meal time, or just charging, or just dinner without charging).
- "amenities" should be the actual on-site amenities the driver will find. Use lowercase kebab-case tokens from this set: restaurant, cafe, fast-food, supermarket, toilets, shopping, wifi, playground, ev-charging, destination-charging, hotel, coffee, viewpoint, museum, park, beach, gym, pool.

Examples of great combo stops to favour when they fit the route:
- UK: Tebay Services (M6) — independent local food + Supercharger. Gretna Green — Supercharger + outlet shopping + cafe.
- France: Aire de Beaune (A6) — Supercharger + regional bakery + wine country.
- Germany: Autohof Lutterberg (A7) — Supercharger + traditional restaurant.
- Netherlands: Schoonebeek — Supercharger near restaurant cluster.
- Switzerland: St. Gallen — Supercharger + lakeside cafe.

Conversation history:
${messages.map(m => `${m.role.toUpperCase()}: ${m.content}`).join('\n')}

Respond with ONLY the JSON object.`;
  }

  async chat(messages: ChatMessage[], itinerary: any, vehicle: VehicleInput): Promise<GrokResponse> {
    const requestId = crypto.randomUUID().slice(0, 8);
    log.info({ requestId, vehicle: vehicleName(vehicle), messageCount: messages.length }, '=== NEW CHAT REQUEST ===');

    const activeProvider = await this.getActiveProvider(requestId);

    if (activeProvider === 'xai') {
      return this.callXaiApi(messages, itinerary, vehicle, requestId);
    }
    if (activeProvider === 'fallback') {
      return this.dumbFallback(messages, requestId);
    }

    // LOCAL PERSONAL GROK CLI
    const prompt = this.buildPrompt(messages, itinerary, vehicle);
    const tmp = await mkdtemp(join(tmpdir(), 'grok-eu-'));

    const disallowed = env.nodeEnv === 'development'
      ? 'search_replace,write_file,Agent,run_terminal_cmd'
      : 'run_terminal_cmd,search_replace,write_file,Agent';

    try {
      const args = [
        '-p', prompt,
        '--output-format', 'json',
        '--yolo',
        '--disallowed-tools', disallowed,
        '--tools', 'web_search,web_fetch',
        '--max-turns', '6',
        '--cwd', tmp,
      ];

      log.info({ requestId, bin: env.grokBin }, 'Spawning local authenticated grok CLI (pure JSON mode)');

      const result = await new Promise<string>((resolve, reject) => {
        const child = spawn(env.grokBin, args, {
          cwd: tmp,
          env: { ...process.env },
          stdio: ['ignore', 'pipe', 'pipe'],
        });

        let stdout = '';
        let stderr = '';
        child.stdout.on('data', (d) => { stdout += d; });
        child.stderr.on('data', (d) => { stderr += d; });

        child.on('close', (code) => {
          if (code === 0) resolve(stdout);
          else {
            log.error({ requestId, code, stderr: stderr.slice(-800) }, 'Local grok CLI exited non-zero');
            reject(new Error(`grok exited with code ${code}`));
          }
        });
        child.on('error', reject);
      });

      const data = JSON.parse(result) as { text?: string };
      const rawText = data.text || '';
      const { text: cleanText, itinerary: parsed } = this.parseGrokResponse(rawText);
      log.info({ requestId, hasItinerary: !!parsed }, 'Local Grok CLI returned JSON response');
      return { text: cleanText, updatedItinerary: parsed };

    } catch (err) {
      log.error({ requestId, err: String(err) }, 'Local authenticated Grok CLI failed — falling back to xAI API');
      if (env.xaiApiKey) {
        return this.callXaiApi(messages, itinerary, vehicle, requestId);
      }
      return this.dumbFallback(messages, requestId);
    } finally {
      await rm(tmp, { recursive: true, force: true }).catch(() => {});
    }
  }

  private async callXaiApi(messages: ChatMessage[], itinerary: any, vehicle: VehicleInput, requestId: string): Promise<GrokResponse> {
    const prompt = this.buildPrompt(messages, itinerary, vehicle);
    log.info({ requestId, promptLength: prompt.length, model: 'grok-4.3' }, 'Calling xAI API (grok-4.3 + JSON mode)');

    try {
      const response = await fetch('https://api.x.ai/v1/chat/completions', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${env.xaiApiKey}`,
        },
        body: JSON.stringify({
          model: 'grok-4.3',
          messages: [{ role: 'user', content: prompt }],
          temperature: 0.6,
          response_format: { type: 'json_object' },
        }),
      });

      if (!response.ok) {
        const text = await response.text();
        log.error({ requestId, status: response.status, body: text }, 'xAI API error');
        return this.dumbFallback(messages, requestId);
      }

      const data = (await response.json()) as { choices?: { message?: { content?: string } }[] };
      const rawText = data.choices?.[0]?.message?.content || '';
      const { text: cleanText, itinerary: parsed } = this.parseGrokResponse(rawText);
      return { text: cleanText, updatedItinerary: parsed };
    } catch (err) {
      log.error({ requestId, err }, 'xAI API call failed');
      return this.dumbFallback(messages, requestId);
    }
  }

  private parseGrokResponse(rawText: string): { text: string; itinerary: any | null } {
    try {
      const cleaned = rawText.trim().replace(/^```json\s*/, '').replace(/```$/, '').trim();
      const parsed = JSON.parse(cleaned);

      if (parsed && typeof parsed === 'object') {
        return {
          text: parsed.message || parsed.reply || '',
          itinerary: parsed.itinerary || null,
        };
      }
    } catch (e) {
      log.warn({ err: String(e), raw: rawText.slice(0, 300) }, 'Failed to parse Grok response as JSON');
    }

    // Fallback to old sentinel method
    return this.extractItineraryUpdate(rawText);
  }

  private extractItineraryUpdate(text: string): { text: string; itinerary: any | null } {
    const upperText = text.toUpperCase();
    const sentinelIndex = upperText.indexOf(SENTINEL.toUpperCase());
    if (sentinelIndex === -1) return { text: text.trim(), itinerary: null };

    const after = text.substring(sentinelIndex + SENTINEL.length).trim();
    let jsonStart = after.indexOf('{');
    if (jsonStart === -1) return { text: text.substring(0, sentinelIndex).trim(), itinerary: null };

    let depth = 0, end = -1, inString = false, escape = false;
    for (let i = jsonStart; i < after.length; i++) {
      const ch = after[i];
      if (escape) { escape = false; continue; }
      if (ch === '\\') { escape = true; continue; }
      if (ch === '"') { inString = !inString; continue; }
      if (!inString) {
        if (ch === '{') depth++;
        if (ch === '}') { depth--; if (depth === 0) { end = i; break; } }
      }
    }
    if (end === -1) return { text: text.substring(0, sentinelIndex).trim(), itinerary: null };

    const jsonStr = after.substring(jsonStart, end + 1);
    try {
      const parsed = JSON.parse(jsonStr);
      return { text: text.substring(0, sentinelIndex).trim(), itinerary: parsed };
    } catch (e) {
      return { text: text.substring(0, sentinelIndex).trim(), itinerary: null };
    }
  }

  private async dumbFallback(messages: ChatMessage[], requestId: string): Promise<GrokResponse> {
    const last = messages[messages.length - 1]?.content.toLowerCase() || '';
    if (['hi', 'hello', 'hey'].some(g => last.includes(g))) {
      return { text: "Hello! I'm Grok Drive. How can I help plan your UK or European Tesla trip today?", updatedItinerary: null };
    }
    return { text: "I'm ready to plan a great Tesla route for you across the UK and Europe. Tell me where you want to go!", updatedItinerary: null };
  }

  async getStatus() {
    const localBinExists = await this.localBinaryExists();
    let provider: 'local' | 'xai' | 'fallback' = 'fallback';
    let label = 'Fallback';
    let detail = 'Basic responses only';

    if (env.forceXaiApi && env.xaiApiKey) {
      provider = 'xai'; label = 'grok-4.3 API'; detail = 'Production path (xAI)';
    } else if (!env.grokEnabled) {
      provider = env.xaiApiKey ? 'xai' : 'fallback';
    } else if (localBinExists) {
      provider = 'local'; label = 'Local Heavy'; detail = 'Your authenticated Grok (free)';
    } else if (env.xaiApiKey) {
      provider = 'xai'; label = 'grok-4.3 API'; detail = 'Production path (xAI)';
    }
    return { provider, label, detail, isLocal: provider === 'local', model: provider === 'local' ? 'Heavy (personal)' : 'grok-4.3', bin: env.grokBin };
  }

  private async localBinaryExists(): Promise<boolean> {
    try { await access(env.grokBin); return true; } catch { return false; }
  }
}

export const grok = new GrokHeadlessClient();