/**
 * AI Credits Admin Panel
 * 
 * Admin UI for managing AI credits:
 * - View any user's balance
 * - View transaction history (ledger)
 * - Manually adjust credits (ADD/DEDUCT)
 * - Reconcile reports
 */

import { createSignal, createResource, createMemo, Show, For, Suspense } from "solid-js";
import { useAuth } from "~/lib/auth";

const API = '/api';

// Types
interface Wallet {
  available_credits: number;
  monthly_credits_total: number;
  monthly_credits_used: number;
  purchased_credits_total: number;
  purchased_credits_used: number;
  bonus_credits_total: number;
  bonus_credits_used: number;
  reserved_credits: number;
  locked_credits: number;
  daily_actions_used: number;
  daily_credits_used: number;
}

interface LedgerEntry {
  id: string;
  entry_type: string;
  credits: number;
  balance_after: number;
  description: string | null;
  idempotency_key: string | null;
  created_at: string;
}

interface AdjustRequest {
  user_id: string;
  amount: number;
  type: 'ADD' | 'DEDUCT';
  reason: string;
}

// API Functions
async function fetchUserBalance(userId: string): Promise<Wallet> {
  const token = sessionStorage.getItem('nxtgauge_access_token');
  const res = await fetch(`${API}/admin/ai-credits/balance?userId=${encodeURIComponent(userId)}`, {
    headers: {
      'Authorization': `Bearer ${token}`,
      'Content-Type': 'application/json',
    },
    credentials: 'include',
  });
  if (!res.ok) throw new Error(await res.text());
  return res.json();
}

async function fetchUserLedger(userId: string, page: number = 1, limit: number = 20): Promise<{ data: LedgerEntry[]; total: number }> {
  const token = sessionStorage.getItem('nxtgauge_access_token');
  const res = await fetch(
    `${API}/admin/ai-credits/ledger?userId=${encodeURIComponent(userId)}&page=${page}&limit=${limit}`,
    {
      headers: {
        'Authorization': `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      credentials: 'include',
    }
  );
  if (!res.ok) throw new Error(await res.text());
  return res.json();
}

async function adjustCredits(request: AdjustRequest): Promise<{ wallet: Wallet; success: boolean }> {
  const token = sessionStorage.getItem('nxtgauge_access_token');
  const res = await fetch(`${API}/admin/ai-credits/adjust`, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${token}`,
      'Content-Type': 'application/json',
    },
    credentials: 'include',
    body: JSON.stringify(request),
  });
  if (!res.ok) throw new Error(await res.text());
  return res.json();
}

export default function AiCreditsAdmin() {
  const auth = useAuth();
  const [activeTab, setActiveTab] = createSignal<'balance' | 'ledger' | 'adjust' | 'reconcile'>('balance');
  
  // Balance tab state
  const [userIdInput, setUserIdInput] = createSignal('');
  const [balanceData, setBalanceData] = createSignal<Wallet | null>(null);
  const [balanceError, setBalanceError] = createSignal('');
  const [balanceLoading, setBalanceLoading] = createSignal(false);
  
  // Ledger tab state
  const [ledgerUserId, setLedgerUserId] = createSignal('');
  const [ledgerPage, setLedgerPage] = createSignal(1);
  const [ledgerData, setLedgerData] = createSignal<{ data: LedgerEntry[]; total: number } | null>(null);
  const [ledgerError, setLedgerError] = createSignal('');
  const [ledgerLoading, setLedgerLoading] = createSignal(false);
  
  // Adjust tab state
  const [adjustForm, setAdjustForm] = createSignal<AdjustRequest>({
    user_id: '',
    amount: 100,
    type: 'ADD',
    reason: '',
  });
  const [adjustResult, setAdjustResult] = createSignal<{ wallet: Wallet; success: boolean } | null>(null);
  const [adjustError, setAdjustError] = createSignal('');
  const [adjustLoading, setAdjustLoading] = createSignal(false);
  
  // Reconcile tab state
  const [reconcileFrom, setReconcileFrom] = createSignal('');
  const [reconcileTo, setReconcileTo] = createSignal('');

  const handleFetchBalance = async () => {
    if (!userIdInput()) {
      setBalanceError('Please enter a User ID');
      return;
    }
    setBalanceLoading(true);
    setBalanceError('');
    try {
      const data = await fetchUserBalance(userIdInput());
      setBalanceData(data);
    } catch (e: any) {
      setBalanceError(e.message || 'Failed to fetch balance');
    } finally {
      setBalanceLoading(false);
    }
  };

  const handleFetchLedger = async () => {
    if (!ledgerUserId()) {
      setLedgerError('Please enter a User ID');
      return;
    }
    setLedgerLoading(true);
    setLedgerError('');
    try {
      const data = await fetchUserLedger(ledgerUserId(), ledgerPage());
      setLedgerData(data);
    } catch (e: any) {
      setLedgerError(e.message || 'Failed to fetch ledger');
    } finally {
      setLedgerLoading(false);
    }
  };

  const handleAdjust = async () => {
    if (!adjustForm().user_id || !adjustForm().amount || !adjustForm().reason) {
      setAdjustError('Please fill in all fields');
      return;
    }
    if (adjustForm().amount <= 0) {
      setAdjustError('Amount must be positive');
      return;
    }
    if (adjustForm().reason.trim().length < 5) {
      setAdjustError('Please provide a detailed reason (at least 5 characters)');
      return;
    }
    setAdjustLoading(true);
    setAdjustError('');
    try {
      const result = await adjustCredits(adjustForm());
      setAdjustResult(result);
    } catch (e: any) {
      setAdjustError(e.message || 'Failed to adjust credits');
    } finally {
      setAdjustLoading(false);
    }
  };

  const formatCurrency = (credits: number) => credits.toLocaleString();

  const formatDate = (dateStr: string) => new Date(dateStr).toLocaleString();

  return (
    <div style={{ padding: '24px', 'max-width': '1200px', margin: '0 auto' }}>
      <h1 style={{ 'font-size': '28px', 'font-weight': '600', margin: '0 0 8px 0' }}>
        AI Credits Admin
      </h1>
      <p style={{ color: '#6B7280', margin: '0 0 24px 0' }}>
        Manage AI credits for users across the platform
      </p>

      {/* Tab Navigation */}
      <div style={{ 
        display: 'flex', 
        'border-bottom': '1px solid #E5E7EB', 
        margin: '0 0 24px 0' 
      }}>
        <For each={[
          { key: 'balance', label: 'View Balance' },
          { key: 'ledger', label: 'Transaction History' },
          { key: 'adjust', label: 'Adjust Credits' },
          { key: 'reconcile', label: 'Reconcile' },
        ]}>{tab => (
          <button
            onClick={() => setActiveTab(tab.key as any)}
            style={{
              padding: '12px 20px',
              'font-size': '14px',
              'font-weight': activeTab() === tab.key ? '600' : '400',
              color: activeTab() === tab.key ? '#FF5E13' : '#6B7280',
              border: 'none',
              'border-bottom': activeTab() === tab.key ? '2px solid #FF5E13' : '2px solid transparent',
              background: 'transparent',
              cursor: 'pointer',
              transition: 'all 0.2s',
            }}
          >
            {tab.label}
          </button>
        )}</For>
      </div>

      {/* Balance Tab */}
      <Show when={activeTab() === 'balance'}>
        <div style={{ 'background-color': 'white', padding: '24px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
          <div style={{ display: 'flex', gap: '12px', 'margin-bottom': '24px' }}>
            <input
              type="text"
              value={userIdInput()}
              onInput={(e) => setUserIdInput(e.currentTarget.value)}
              placeholder="Enter User ID (UUID)"
              style={{
                flex: '1',
                padding: '10px 14px',
                'font-size': '14px',
                border: '1px solid #D1D5DB',
                'border-radius': '6px',
              }}
            />
            <button
              onClick={handleFetchBalance}
              disabled={balanceLoading()}
              style={{
                padding: '10px 20px',
                'font-size': '14px',
                'font-weight': '500',
                color: 'white',
                background: balanceLoading() ? '#9CA3AF' : '#FF5E13',
                border: 'none',
                'border-radius': '6px',
                cursor: balanceLoading() ? 'not-allowed' : 'pointer',
              }}
            >
              {balanceLoading() ? 'Loading...' : 'View Balance'}
            </button>
          </div>

          <Show when={balanceError()}>
            <div style={{ 
              padding: '12px 16px', 
              'background-color': '#FEE2E2', 
              color: '#991B1B',
              'border-radius': '6px',
              'margin-bottom': '16px'
            }}>
              {balanceError()}
            </div>
          </Show>

          <Show when={balanceData()}>
            {(wallet) => (
              <div style={{ display: 'grid', 'grid-template-columns': 'repeat(auto-fit, minmax(200px, 1fr))', gap: '16px' }}>
                <div style={{ 
                  padding: '20px', 
                  'background-color': '#FEF2F0', 
                  'border-radius': '8px',
                  border: '1px solid #FECACA'
                }}>
                  <div style={{ 'font-size': '12px', 'text-transform': 'uppercase', 'letter-spacing': '0.5px', color: '#991B1B' }}>
                    Available Credits
                  </div>
                  <div style={{ 'font-size': '32px', 'font-weight': '700', color: '#FF5E13' }}>
                    {formatCurrency(wallet().available_credits)}
                  </div>
                </div>

                <div style={{ padding: '20px', 'background-color': '#F3F4F6', 'border-radius': '8px' }}>
                  <div style={{ 'font-size': '12px', 'text-transform': 'uppercase', 'letter-spacing': '0.5px', color: '#6B7280' }}>
                    Monthly Credits
                  </div>
                  <div style={{ 'font-size': '24px', 'font-weight': '600' }}>
                    {formatCurrency(wallet().monthly_credits_total - wallet().monthly_credits_used)} / {formatCurrency(wallet().monthly_credits_total)}
                  </div>
                  <div style={{ 'font-size': '12px', color: '#6B7280' }}>
                    Used: {formatCurrency(wallet().monthly_credits_used)}
                  </div>
                </div>

                <div style={{ padding: '20px', 'background-color': '#F3F4F6', 'border-radius': '8px' }}>
                  <div style={{ 'font-size': '12px', 'text-transform': 'uppercase', 'letter-spacing': '0.5px', color: '#6B7280' }}>
                    Purchased Credits
                  </div>
                  <div style={{ 'font-size': '24px', 'font-weight': '600' }}>
                    {formatCurrency(wallet().purchased_credits_total - wallet().purchased_credits_used)} / {formatCurrency(wallet().purchased_credits_total)}
                  </div>
                  <div style={{ 'font-size': '12px', color: '#6B7280' }}>
                    Used: {formatCurrency(wallet().purchased_credits_used)}
                  </div>
                </div>

                <div style={{ padding: '20px', 'background-color': '#F3F4F6', 'border-radius': '8px' }}>
                  <div style={{ 'font-size': '12px', 'text-transform': 'uppercase', 'letter-spacing': '0.5px', color: '#6B7280' }}>
                    Bonus Credits
                  </div>
                  <div style={{ 'font-size': '24px', 'font-weight': '600' }}>
                    {formatCurrency(wallet().bonus_credits_total - wallet().bonus_credits_used)} / {formatCurrency(wallet().bonus_credits_total)}
                  </div>
                  <div style={{ 'font-size': '12px', color: '#6B7280' }}>
                    Used: {formatCurrency(wallet().bonus_credits_used)}
                  </div>
                </div>

                <div style={{ padding: '20px', 'background-color': '#FEF3C7', 'border-radius': '8px' }}>
                  <div style={{ 'font-size': '12px', 'text-transform': 'uppercase', 'letter-spacing': '0.5px', color: '#92400E' }}>
                    Reserved
                  </div>
                  <div style={{ 'font-size': '24px', 'font-weight': '600', color: '#B45309' }}>
                    {formatCurrency(wallet().reserved_credits)}
                  </div>
                </div>

                <div style={{ padding: '20px', 'background-color': '#E0E7FF', 'border-radius': '8px' }}>
                  <div style={{ 'font-size': '12px', 'text-transform': 'uppercase', 'letter-spacing': '0.5px', color: '#3730A3' }}>
                    Locked
                  </div>
                  <div style={{ 'font-size': '24px', 'font-weight': '600', color: '#4338CA' }}>
                    {formatCurrency(wallet().locked_credits)}
                  </div>
                </div>
              </div>
            )}
          </Show>
        </div>
      </Show>

      {/* Ledger Tab */}
      <Show when={activeTab() === 'ledger'}>
        <div style={{ 'background-color': 'white', padding: '24px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
          <div style={{ display: 'flex', gap: '12px', 'margin-bottom': '24px' }}>
            <input
              type="text"
              value={ledgerUserId()}
              onInput={(e) => setLedgerUserId(e.currentTarget.value)}
              placeholder="Enter User ID (UUID)"
              style={{
                flex: '1',
                padding: '10px 14px',
                'font-size': '14px',
                border: '1px solid #D1D5DB',
                'border-radius': '6px',
              }}
            />
            <button
              onClick={handleFetchLedger}
              disabled={ledgerLoading()}
              style={{
                padding: '10px 20px',
                'font-size': '14px',
                'font-weight': '500',
                color: 'white',
                background: ledgerLoading() ? '#9CA3AF' : '#FF5E13',
                border: 'none',
                'border-radius': '6px',
                cursor: ledgerLoading() ? 'not-allowed' : 'pointer',
              }}
            >
              {ledgerLoading() ? 'Loading...' : 'View History'}
            </button>
          </div>

          <Show when={ledgerError()}>
            <div style={{ 
              padding: '12px 16px', 
              'background-color': '#FEE2E2', 
              color: '#991B1B',
              'border-radius': '6px',
              'margin-bottom': '16px'
            }}>
              {ledgerError()}
            </div>
          </Show>

          <Show when={ledgerData()}>
            {(data) => (
              <div>
                <div style={{ 'margin-bottom': '16px', color: '#6B7280', 'font-size': '14px' }}>
                  Showing {data().data.length} of {data().total} entries
                </div>
                
                <div style={{ overflow: 'auto' }}>
                  <table style={{ width: '100%', 'border-collapse': 'collapse' }}>
                    <thead>
                      <tr style={{ 'background-color': '#F9FAFB', 'border-bottom': '1px solid #E5E7EB' }}>
                        <th style={{ padding: '12px', 'text-align': 'left', 'font-size': '12px', 'font-weight': '600', color: '#6B7280' }}>Date</th>
                        <th style={{ padding: '12px', 'text-align': 'left', 'font-size': '12px', 'font-weight': '600', color: '#6B7280' }}>Type</th>
                        <th style={{ padding: '12px', 'text-align': 'right', 'font-size': '12px', 'font-weight': '600', color: '#6B7280' }}>Credits</th>
                        <th style={{ padding: '12px', 'text-align': 'right', 'font-size': '12px', 'font-weight': '600', color: '#6B7280' }}>Balance After</th>
                        <th style={{ padding: '12px', 'text-align': 'left', 'font-size': '12px', 'font-weight': '600', color: '#6B7280' }}>Description</th>
                      </tr>
                    </thead>
                    <tbody>
                      <For each={data().data}>
                        {(entry) => (
                          <tr style={{ 'border-bottom': '1px solid #E5E7EB' }}>
                            <td style={{ padding: '12px', 'font-size': '14px' }}>
                              {formatDate(entry.created_at)}
                            </td>
                            <td style={{ padding: '12px' }}>
                              <span style={{
                                padding: '4px 8px',
                                'border-radius': '4px',
                                'font-size': '12px',
                                'font-weight': '500',
                                'background-color': entry.entry_type.includes('credit') ? '#D1FAE5' : entry.entry_type.includes('debit') ? '#FEE2E2' : '#F3F4F6',
                                color: entry.entry_type.includes('credit') ? '#065F46' : entry.entry_type.includes('debit') ? '#991B1B' : '#374151'
                              }}>
                                {entry.entry_type}
                              </span>
                            </td>
                            <td style={{ padding: '12px', 'text-align': 'right', 'font-size': '14px', 'font-weight': '500' }}>
                              {entry.credits > 0 ? '+' : ''}{formatCurrency(entry.credits)}
                            </td>
                            <td style={{ padding: '12px', 'text-align': 'right', 'font-size': '14px' }}>
                              {formatCurrency(entry.balance_after)}
                            </td>
                            <td style={{ padding: '12px', 'font-size': '14px', color: '#6B7280' }}>
                              {entry.description || '-'}
                            </td>
                          </tr>
                        )}
                      </For>
                    </tbody>
                  </table>
                </div>

                <div style={{ display: 'flex', 'justify-content': 'center', gap: '8px', 'margin-top': '16px' }}>
                  <button
                    onClick={() => {
                      setLedgerPage(p => Math.max(1, p - 1));
                      handleFetchLedger();
                    }}
                    disabled={ledgerPage() === 1}
                    style={{
                      padding: '8px 16px',
                      border: '1px solid #D1D5DB',
                      'border-radius': '6px',
                      background: ledgerPage() === 1 ? '#F3F4F6' : 'white',
                      cursor: ledgerPage() === 1 ? 'not-allowed' : 'pointer',
                    }}
                  >
                    Previous
                  </button>
                  <span style={{ padding: '8px 16px', color: '#6B7280' }}>
                    Page {ledgerPage()}
                  </span>
                  <button
                    onClick={() => {
                      setLedgerPage(p => p + 1);
                      handleFetchLedger();
                    }}
                    disabled={ledgerData()?.data.length === 0 || (ledgerData()?.data.length ?? 0) < 20}
                    style={{
                      padding: '8px 16px',
                      border: '1px solid #D1D5DB',
                      'border-radius': '6px',
                      background: 'white',
                      cursor: 'pointer',
                    }}
                  >
                    Next
                  </button>
                </div>
              </div>
            )}
          </Show>
        </div>
      </Show>

      {/* Adjust Tab */}
      <Show when={activeTab() === 'adjust'}>
        <div style={{ 'background-color': 'white', padding: '24px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
          <div style={{ display: 'flex', 'flex-direction': 'column', gap: '16px' }}>
            <div>
              <label style={{ display: 'block', 'margin-bottom': '6px', 'font-size': '14px', 'font-weight': '500' }}>
                User ID
              </label>
              <input
                type="text"
                value={adjustForm().user_id}
                onInput={(e) => setAdjustForm(f => ({ ...f, user_id: e.currentTarget.value }))}
                placeholder="Enter User ID (UUID)"
                style={{
                  width: '100%',
                  padding: '10px 14px',
                  'font-size': '14px',
                  border: '1px solid #D1D5DB',
                  'border-radius': '6px',
                }}
              />
            </div>

            <div style={{ display: 'grid', 'grid-template-columns': '1fr 1fr', gap: '16px' }}>
              <div>
                <label style={{ display: 'block', 'margin-bottom': '6px', 'font-size': '14px', 'font-weight': '500' }}>
                  Operation Type
                </label>
                <select
                  value={adjustForm().type}
                  onChange={(e) => setAdjustForm(f => ({ ...f, type: e.currentTarget.value as 'ADD' | 'DEDUCT' }))}
                  style={{
                    width: '100%',
                    padding: '10px 14px',
                    'font-size': '14px',
                    border: '1px solid #D1D5DB',
                    'border-radius': '6px',
                  }}
                >
                  <option value="ADD">Add Credits (+)</option>
                  <option value="DEDUCT">Deduct Credits (-)</option>
                </select>
              </div>

              <div>
                <label style={{ display: 'block', 'margin-bottom': '6px', 'font-size': '14px', 'font-weight': '500' }}>
                  Amount
                </label>
                <input
                  type="number"
                  min="1"
                  value={adjustForm().amount}
                  onInput={(e) => setAdjustForm(f => ({ ...f, amount: parseInt(e.currentTarget.value) || 0 }))}
                  style={{
                    width: '100%',
                    padding: '10px 14px',
                    'font-size': '14px',
                    border: '1px solid #D1D5DB',
                    'border-radius': '6px',
                  }}
                />
              </div>
            </div>

            <div>
              <label style={{ display: 'block', 'margin-bottom': '6px', 'font-size': '14px', 'font-weight': '500' }}>
                Reason (Required)
              </label>
              <textarea
                value={adjustForm().reason}
                onInput={(e) => setAdjustForm(f => ({ ...f, reason: e.currentTarget.value }))}
                placeholder="Explain why you're adjusting these credits (for audit purposes)"
                rows={3}
                style={{
                  width: '100%',
                  padding: '10px 14px',
                  'font-size': '14px',
                  border: '1px solid #D1D5DB',
                  'border-radius': '6px',
                  resize: 'vertical',
                }}
              />
            </div>

            <button
              onClick={handleAdjust}
              disabled={adjustLoading()}
              style={{
                padding: '12px 24px',
                'font-size': '14px',
                'font-weight': '500',
                color: 'white',
                background: adjustLoading() ? '#9CA3AF' : '#FF5E13',
                border: 'none',
                'border-radius': '6px',
                cursor: adjustLoading() ? 'not-allowed' : 'pointer',
                'margin-top': '8px',
              }}
            >
              {adjustLoading() ? 'Processing...' : adjustForm().type === 'ADD' ? 'Add Credits' : 'Deduct Credits'}
            </button>
          </div>

          <Show when={adjustError()}>
            <div style={{ 
              padding: '12px 16px', 
              'background-color': '#FEE2E2', 
              color: '#991B1B',
              'border-radius': '6px',
              'margin-top': '16px'
            }}>
              {adjustError()}
            </div>
          </Show>

          <Show when={adjustResult()}>
            {(result) => (
              <div style={{ 
                padding: '16px', 
                'background-color': '#D1FAE5', 
                color: '#065F46',
                'border-radius': '6px',
                'margin-top': '16px'
              }}>
                <div style={{ 'font-weight': '600', 'margin-bottom': '8px' }}>
                  ✓ Credits adjusted successfully!
                </div>
                <div>New available balance: {formatCurrency(result().wallet.available_credits)} credits</div>
              </div>
            )}
          </Show>
        </div>
      </Show>

      {/* Reconcile Tab */}
      <Show when={activeTab() === 'reconcile'}>
        <div style={{ 'background-color': 'white', padding: '24px', 'border-radius': '8px', 'box-shadow': '0 1px 3px rgba(0,0,0,0.1)' }}>
          <div style={{ display: 'flex', 'flex-direction': 'column', gap: '16px' }}>
            <div>
              <p style={{ color: '#6B7280', 'margin-bottom': '16px' }}>
                Generate a reconciliation report to verify ledger entries match wallet balances.
                This helps identify any drift or discrepancies in the system.
              </p>
            </div>

            <div style={{ display: 'grid', 'grid-template-columns': '1fr 1fr', gap: '16px' }}>
              <div>
                <label style={{ display: 'block', 'margin-bottom': '6px', 'font-size': '14px', 'font-weight': '500' }}>
                  From Date
                </label>
                <input
                  type="datetime-local"
                  value={reconcileFrom()}
                  onInput={(e) => setReconcileFrom(e.currentTarget.value)}
                  style={{
                    width: '100%',
                    padding: '10px 14px',
                    'font-size': '14px',
                    border: '1px solid #D1D5DB',
                    'border-radius': '6px',
                  }}
                />
              </div>

              <div>
                <label style={{ display: 'block', 'margin-bottom': '6px', 'font-size': '14px', 'font-weight': '500' }}>
                  To Date
                </label>
                <input
                  type="datetime-local"
                  value={reconcileTo()}
                  onInput={(e) => setReconcileTo(e.currentTarget.value)}
                  style={{
                    width: '100%',
                    padding: '10px 14px',
                    'font-size': '14px',
                    border: '1px solid #D1D5DB',
                    'border-radius': '6px',
                  }}
                />
              </div>
            </div>

            <button
              onClick={() => {
                // This would call the reconcile API endpoint
                alert('Reconcile endpoint to be implemented in backend');
              }}
              style={{
                padding: '12px 24px',
                'font-size': '14px',
                'font-weight': '500',
                color: 'white',
                background: '#374151',
                border: 'none',
                'border-radius': '6px',
                cursor: 'pointer',
                'margin-top': '8px',
              }}
            >
              Generate Reconcile Report
            </button>
          </div>
        </div>
      </Show>
    </div>
  );
}
