import requests
import json
import config
from utils import normalize_date
import time

# =====================================================
#  1. AUTHENTICATION
# =====================================================
def get_headers():
    try:
        params = {
            "refresh_token": config.REFRESH_TOKEN,
            "client_id": config.CLIENT_ID,
            "client_secret": config.CLIENT_SECRET,
            "grant_type": "refresh_token",
            "redirect_uri": "http://www.google.com"
        }
        # Added 10s timeout to prevent hanging
        resp = requests.post(config.AUTH_URL, data=params, timeout=10) 
        if resp.status_code == 200:
            return {"Authorization": f"Zoho-oauthtoken {resp.json().get('access_token')}"}
    except Exception as e:
        print(f"Auth Error: {e}")
    return None

# =====================================================
#  2. DIRECT CUSTOMER RESOLVER
# =====================================================
def get_customer_id(name, headers):
    """
    Strict Logic: Search -> Found? -> Return ID. 
    Else -> Create -> Return ID.
    """
    if not name or str(name).lower() in ["unknown", "none"]:
        name = "MCP Generic Customer"

    print(f"   🔎 Searching Zoho for: '{name}'...")
    
    # --- STEP 1: SEARCH ---
    search_url = f"{config.API_BASE}/contacts"
    search_params = {
        'organization_id': config.ORGANIZATION_ID, 
        'contact_name_contains': name
    }
    
    try:
        # 10s Timeout
        res = requests.get(search_url, headers=headers, params=search_params, timeout=10)
        
        if res.status_code == 200:
            contacts = res.json().get('contacts', [])
            if len(contacts) > 0:
                # MATCH FOUND!
                found_id = contacts[0]['contact_id']
                print(f"   ✅ Found Existing Customer: {contacts[0]['contact_name']} ({found_id})")
                return found_id
        else:
            print(f"   ⚠️ Search API Status: {res.status_code} (Not 200)")
            
    except Exception as e:
        print(f"   ❌ Search Exception: {e}")

    # --- STEP 2: CREATE (Only if Search failed) ---
    print(f"   🆕 Not found. Creating new customer: '{name}'...")
    
    create_payload = {
        "contact_name": name,
        "contact_type": "customer"
    }
    
    try:
        res = requests.post(search_url, headers=headers, params={'organization_id': config.ORGANIZATION_ID}, json=create_payload, timeout=10)
        
        if res.status_code == 201:
            new_id = res.json().get('contact', {}).get('contact_id')
            print(f"   ✅ Created New: {new_id}")
            return new_id
        
        # Handle Duplicate Error (Race Condition)
        if res.json().get('code') == 3062:
            print("   ⚠️ Zoho says Duplicate. Forcing Search on exact name...")
            # Logic: If we are here, the 'contains' search failed, but it exists.
            # We assume it exists and we just failed to fetch it. 
            # We cannot proceed without an ID.
            return None

        print(f"   ❌ Creation Failed: {res.text}")
        
    except Exception as e:
        print(f"   ❌ Create Exception: {e}")

    return None

# =====================================================
#  3. INVOICE PUSHER
# =====================================================
def create_invoice(cid, ai_data, headers):
    print("   📦 Preparing Invoice Payload...")
    
    # 1. Process Line Items (Handle 0 items case)
    raw_items = ai_data.get('line_items', [])
    clean_items = []
    
    if raw_items:
        for item in raw_items:
            clean_items.append({
                "name": str(item.get("name", "Service"))[:100], # Limit 100 chars
                "rate": float(item.get("rate", 0)),
                "quantity": float(item.get("quantity", 1))
            })
    
    # Fallback if list is empty
    if not clean_items:
        print("   ⚠️ No items found. Using Default 'Services Rendered' Item.")
        clean_items = [{
            "name": "Services Rendered",
            "description": "Auto-generated from document total",
            "rate": float(ai_data.get("total", 0)),
            "quantity": 1
        }]

    # 2. Build Payload
    payload = {
        "customer_id": cid,
        "date": normalize_date(ai_data.get("date")),
        "invoice_number": ai_data.get("reference_number") or f"INV-{int(time.time())}",
        "line_items": clean_items,
        "status": "draft"
    }

    # 3. Send
    url = f"{config.API_BASE}/invoices?organization_id={config.ORGANIZATION_ID}"
    try:
        print("   🚀 Sending Invoice to Zoho...")
        res = requests.post(url, headers=headers, json=payload, timeout=15)
        
        # Auto-Number Retry
        if res.status_code != 201 and res.json().get('code') == 4097:
            print("   ⚠️ Auto-Numbering active. Removing ID and Retrying...")
            del payload['invoice_number']
            res = requests.post(url, headers=headers, json=payload, timeout=15)

        if res.status_code == 201:
            inv = res.json().get('invoice', {})
            return f"✅ SUCCESS! Invoice Created.\nNumber: {inv.get('invoice_number')}\nLink: https://books.zoho.in/app/{config.ORGANIZATION_ID}#/invoices/{inv.get('invoice_id')}"
        
        return f"❌ Zoho Error: {res.text}"

    except Exception as e:
        return f"❌ Connection Error: {e}"

# =====================================================
#  4. MAIN EXECUTOR
# =====================================================
def route_and_execute(ai_output):
    # 1. Get Auth
    headers = get_headers()
    if not headers:
        yield "❌ Auth Failed. Check Credentials."
        return

    # 2. Get Data
    data = ai_output.get('data', {})
    vendor_name = data.get('vendor_name')
    
    yield f"🔄 Processing Invoice for: {vendor_name}\n"

    # 3. Get Customer ID
    cid = get_customer_id(vendor_name, headers)
    
    if not cid:
        # HARD FALLBACK: If name search fails, try generic
        yield "   ⚠️ Specific customer failed. Trying 'Generic' fallback...\n"
        cid = get_customer_id("MCP Generic Customer", headers)
        if not cid:
            yield "🛑 Critical: Could not find/create any customer."
            return

    yield f"   -> Customer ID: {cid}\n"

    # 4. Create Invoice
    result = create_invoice(cid, data, headers)
    yield result