'use client';

import { useState, useEffect } from 'react';
import axios from 'axios';
import toast from 'react-hot-toast';
import { motion } from 'framer-motion';
import { fadeUp, stagger } from '@/lib/animations';
import { User, ChartBar as BarChart3, Key, Shield, CircleNotch as LoaderCircle, FloppyDisk as Save, Sun, Envelope as Mail, Building as Building2, SignOut as LogOut, CaretRight as ChevronRight, Lightning as Zap, Trash as Trash2, Plus, Copy } from '@phosphor-icons/react';
import { useAuth } from '@/contexts/auth';
import { getSupabase } from '@/lib/supabase';
import { useRouter } from 'next/navigation';
import { getApiKeys, createApiKey, deleteApiKey } from '@/lib/api';
import type { ApiKey } from '@/lib/api';
import { CriticalButton, FlatInput, PageHeader } from '@/components/ui';

function getInitials(name?: string, email?: string): string {
  if (name)  return name.split(' ').map(p => p[0]).slice(0, 2).join('').toUpperCase();
  if (email) return email[0].toUpperCase();
  return 'G';
}

export default function SettingsPage() {
  const { user, isGuest, upgradeToAccount } = useAuth();
  const router = useRouter();

  const [fullName, setFullName]       = useState('');
  const [institution, setInstitution] = useState('');
  const [saving, setSaving]           = useState(false);
  const [loading, setLoading]         = useState(true);
  const [jobsToday, setJobsToday]     = useState(0);
  const [jobsTotal, setJobsTotal]     = useState(0);
  const [dailyLimit, setDailyLimit]   = useState(10);

  const [apiKeys, setApiKeys]           = useState<ApiKey[]>([]);
  const [keysLoading, setKeysLoading]   = useState(false);
  const [creatingKey, setCreatingKey]   = useState(false);
  const [newKeyValue, setNewKeyValue]   = useState<string | null>(null);
  const [keyNameInput, setKeyNameInput] = useState('');

  useEffect(() => {
    const fetchData = async () => {
      try {
        const api = axios.create({ baseURL: '/api/backend' });
        const supabase = getSupabase();
        const { data: { session } } = await supabase.auth.getSession();
        if (session?.access_token) api.defaults.headers.Authorization = `Bearer ${session.access_token}`;

        const [profileRes, countRes, jobsRes] = await Promise.all([
          api.get('/api/profile'),
          api.get('/api/jobs/count'),
          api.get('/api/jobs'),
        ]);

        if (profileRes.data && !profileRes.data.error) {
          setFullName(profileRes.data.full_name || '');
          setInstitution(profileRes.data.institution || '');
        }
        setJobsToday(countRes.data.count   || 0);
        setDailyLimit(countRes.data.limit  || 10);
        setJobsTotal((jobsRes.data.jobs    || []).length);
      } catch { /* guest users may 401 */ } finally { setLoading(false); }
    };
    fetchData();
    if (!isGuest) {
      setKeysLoading(true);
      getApiKeys().then(setApiKeys).catch(() => {}).finally(() => setKeysLoading(false));
    }
  }, [isGuest]);

  const handleSave = async () => {
    setSaving(true);
    try {
      const api = axios.create({ baseURL: '/api/backend' });
      const supabase = getSupabase();
      const { data: { session } } = await supabase.auth.getSession();
      if (session?.access_token) api.defaults.headers.Authorization = `Bearer ${session.access_token}`;
      await api.put('/api/profile', { full_name: fullName, institution });
      toast.success('Profile updated');
    } catch { toast.error('Failed to save settings'); } finally { setSaving(false); }
  };

  const handleSignOut = async () => {
    const supabase = getSupabase();
    await supabase.auth.signOut();
    router.push('/auth');
  };

  const resolvedName  = fullName || (user?.user_metadata?.full_name as string | undefined);
  const initials      = getInitials(resolvedName, user?.email);
  const usagePercent  = Math.min(Math.round((jobsToday / dailyLimit) * 100), 100);
  const memberSince   = user?.created_at
    ? new Date(user.created_at).toLocaleDateString('en-US', { month: 'long', year: 'numeric' })
    : null;

  return (
    <div className="max-w-3xl space-y-8">
      <PageHeader title="Settings" subtitle="Manage your profile, usage, and preferences" />

      <motion.div variants={stagger} animate="show" className="space-y-6">

        {/* ── Profile ── */}
        <motion.section variants={fadeUp} className="glass-card p-6">
          <div className="flex items-center gap-2 mb-6">
            <User className="w-4 h-4 text-accent-cyan" />
            <h2 className="text-base font-semibold text-text-primary">Profile</h2>
          </div>

          {loading ? (
            <div className="flex items-center justify-center py-8">
              <LoaderCircle className="w-5 h-5 animate-spin text-accent-cyan" />
            </div>
          ) : (
            <div className="space-y-5">
              {/* Avatar identity row */}
              <div className="flex items-center gap-4 p-4 rounded-xl bg-surface-0 border border-glass-border">
                <div className="w-14 h-14 rounded-2xl bg-accent-cyan/15 border border-accent-cyan/25 flex items-center justify-center shrink-0">
                  <span className="text-accent-cyan font-bold text-xl tracking-tight">{initials}</span>
                </div>
                <div>
                  <p className="text-sm font-semibold text-text-primary">
                    {resolvedName || (isGuest ? 'Guest User' : 'Synteny User')}
                  </p>
                  <p className="text-xs text-text-muted mt-0.5">{user?.email ?? (isGuest ? 'No account' : '')}</p>
                  {memberSince && <p className="text-[11px] text-text-muted/50 mt-0.5">Member since {memberSince}</p>}
                  {isGuest     && <p className="text-[11px] text-accent-amber mt-0.5">Guest session — data not persisted</p>}
                </div>
              </div>

              {/* Email (read-only) */}
              <div>
                <label className="block text-[11px] font-semibold text-text-muted mb-1.5 uppercase tracking-widest">Email</label>
                <div className="relative">
                  <Mail className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-text-muted" />
                  <input
                    type="email" disabled
                    value={user?.email ?? (isGuest ? 'Guest session' : '')}
                    className="w-full pl-10 pr-4 py-2.5 rounded-xl border border-glass-border bg-surface-0 text-text-muted text-sm cursor-not-allowed"
                  />
                </div>
              </div>

              {/* Editable fields */}
              <div className="grid grid-cols-2 gap-4">
                <div>
                  <label className="block text-[11px] font-semibold text-text-muted mb-1.5 uppercase tracking-widest">Full Name</label>
                  <div className="relative">
                    <User className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-text-muted" />
                    <input
                      type="text" value={fullName} onChange={e => setFullName(e.target.value)}
                      placeholder="Your full name"
                      className="w-full pl-10 pr-4 py-2.5 rounded-xl border border-glass-border focus:border-accent-cyan/40 focus:ring-2 focus:ring-accent-cyan/10 outline-none transition text-sm text-text-primary bg-surface-1"
                    />
                  </div>
                </div>
                <div>
                  <label className="block text-[11px] font-semibold text-text-muted mb-1.5 uppercase tracking-widest">Institution</label>
                  <div className="relative">
                    <Building2 className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-text-muted" />
                    <input
                      type="text" value={institution} onChange={e => setInstitution(e.target.value)}
                      placeholder="University or lab"
                      className="w-full pl-10 pr-4 py-2.5 rounded-xl border border-glass-border focus:border-accent-cyan/40 focus:ring-2 focus:ring-accent-cyan/10 outline-none transition text-sm text-text-primary bg-surface-1"
                    />
                  </div>
                </div>
              </div>

              {isGuest ? (
                <div className="rounded-xl bg-accent-cyan/5 border border-accent-cyan/15 p-5 text-center">
                  <User className="w-10 h-10 text-accent-cyan mx-auto mb-3" />
                  <h3 className="text-sm font-semibold text-text-primary mb-1">Save your work</h3>
                  <p className="text-xs text-text-muted mb-4 max-w-sm mx-auto">
                    Create a free account to keep your analysis history, save settings, and never lose results.
                  </p>
                  <CriticalButton onClick={() => upgradeToAccount()}>
                    <svg className="w-4 h-4" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><path d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92a5.06 5.06 0 0 1-2.2 3.32v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.1z"/><path d="M12 23c2.97 0 5.46-.98 7.28-2.66l-3.57-2.77c-.98.66-2.23 1.06-3.71 1.06-2.86 0-5.29-1.93-6.16-4.53H2.18v2.84C3.99 20.53 7.7 23 12 23z"/><path d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z"/><path d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z"/></svg>
                    Sign in with Google
                  </CriticalButton>
                </div>
              ) : (
                <div className="flex items-center justify-between pt-1">
                  <CriticalButton onClick={handleSave} disabled={saving} loading={saving}>
                    {!saving && <Save className="w-4 h-4" />}
                    Save Profile
                  </CriticalButton>
                </div>
              )}
            </div>
          )}
        </motion.section>

        {/* ── Usage & Plan ── */}
        <motion.section variants={fadeUp} className="glass-card p-6">
          <div className="flex items-center gap-2 mb-6">
            <BarChart3 className="w-4 h-4 text-accent-cyan" />
            <h2 className="text-base font-semibold text-text-primary">Usage & Plan</h2>
          </div>
          <div className="space-y-5">
            <div className="grid grid-cols-3 gap-3">
              {[
                { label: 'Today',    value: jobsToday,   sub: `of ${dailyLimit} limit` },
                { label: 'All time', value: jobsTotal,   sub: 'total runs'             },
                { label: 'Plan',     value: 'Free',      sub: 'no credit card'         },
              ].map(stat => (
                <div key={stat.label} className="rounded-xl p-4 text-center bg-surface-0 border border-glass-border">
                  <p className="text-xl font-bold text-text-primary">{stat.value}</p>
                  <p className="text-xs text-text-muted mt-0.5 font-medium">{stat.label}</p>
                  <p className="text-[10px] text-text-muted/50 mt-0.5">{stat.sub}</p>
                </div>
              ))}
            </div>

            {/* Usage bar */}
            <div>
              <div className="flex items-center justify-between mb-2">
                <span className="text-xs text-text-muted">Daily analyses used</span>
                <span className="text-xs text-text-muted">{jobsToday} / {dailyLimit}</span>
              </div>
              <div className="h-1.5 bg-surface-0 rounded-full overflow-hidden border border-glass-border">
                <motion.div
                  className={`h-full rounded-full ${usagePercent >= 80 ? 'bg-accent-amber' : 'bg-accent-cyan'}`}
                  initial={{ width: 0 }}
                  animate={{ width: `${usagePercent}%` }}
                  transition={{ duration: 0.9, ease: 'easeOut' }}
                />
              </div>
              <p className="text-[11px] text-text-muted mt-2">Resets daily at midnight UTC</p>
            </div>

            {/* Pro upsell stub */}
            <div className="flex items-center justify-between p-3.5 rounded-xl bg-accent-cyan/5 border border-accent-cyan/15 cursor-default">
              <div className="flex items-center gap-2.5">
                <Zap className="w-4 h-4 text-accent-cyan shrink-0" />
                <div>
                  <p className="text-sm font-medium text-text-primary">Need more capacity?</p>
                  <p className="text-xs text-text-muted">Pro plan with higher limits — coming soon</p>
                </div>
              </div>
              <ChevronRight className="w-4 h-4 text-text-muted shrink-0" />
            </div>
          </div>
        </motion.section>

        {/* ── Appearance ── */}
        <motion.section variants={fadeUp} className="glass-card p-6">
          <div className="flex items-center gap-2 mb-4">
            <Sun className="w-4 h-4 text-accent-cyan" />
            <h2 className="text-base font-semibold text-text-primary">Appearance</h2>
          </div>
          <div className="flex items-center justify-between p-3.5 rounded-xl bg-surface-0 border border-glass-border">
            <div>
              <p className="text-sm font-medium text-text-primary">Void Dark</p>
              <p className="text-xs text-text-muted mt-0.5">Designed for long research sessions — reduced eye strain</p>
            </div>
            <span className="text-[10px] px-2.5 py-0.5 rounded-full bg-accent-cyan/10 text-accent-cyan font-medium">Active</span>
          </div>
          <p className="text-xs text-text-muted mt-3">Additional themes will be available in a future update.</p>
        </motion.section>

        {/* ── API Access ── */}
        <motion.section variants={fadeUp} className="glass-card p-6">
          <div className="flex items-center gap-2 mb-4">
            <Key className="w-4 h-4 text-accent-cyan" />
            <h2 className="text-base font-semibold text-text-primary">API Access</h2>
          </div>
          {isGuest ? (
            <div className="p-5 rounded-xl bg-surface-0 border border-glass-border text-center">
              <Key className="w-8 h-8 text-text-muted mx-auto mb-3" />
              <p className="text-sm font-medium text-text-primary">Sign in to access API keys</p>
              <p className="text-xs text-text-muted mt-1 max-w-xs mx-auto">
                Create a free account to generate API keys for programmatic access.
              </p>
            </div>
          ) : (
            <div className="space-y-4">
              <p className="text-sm text-text-secondary">
                Generate API keys to run Synteny pipelines from your scripts.
                Use the <code className="text-accent-cyan text-xs bg-surface-0 px-1.5 py-0.5 rounded">X-API-Key</code> header to authenticate.
              </p>

              {/* Existing keys */}
              {keysLoading ? (
                <div className="flex items-center justify-center py-4">
                  <LoaderCircle className="w-4 h-4 animate-spin text-accent-cyan" />
                </div>
              ) : apiKeys.length > 0 ? (
                <div className="space-y-2">
                  {apiKeys.map(k => (
                    <div key={k.id} className="flex items-center justify-between p-3 rounded-xl bg-surface-0 border border-glass-border">
                      <div className="flex items-center gap-3">
                        <Key className="w-4 h-4 text-text-muted" />
                        <div>
                          <p className="text-sm font-medium text-text-primary">{k.name}</p>
                          <p className="text-xs text-text-muted font-mono">{k.key_prefix}...</p>
                        </div>
                      </div>
                      <div className="flex items-center gap-3">
                        <span className="text-[10px] text-text-muted">
                          {k.last_used_at ? `Used ${new Date(k.last_used_at).toLocaleDateString()}` : 'Never used'}
                        </span>
                        <button
                          onClick={async () => {
                            if (!confirm('Revoke this API key? This cannot be undone.')) return;
                            try {
                              await deleteApiKey(k.id);
                              setApiKeys(prev => prev.filter(x => x.id !== k.id));
                              toast.success('API key revoked');
                            } catch { toast.error('Failed to revoke key'); }
                          }}
                          className="p-1.5 rounded-lg hover:bg-error/10 text-text-muted hover:text-error transition"
                        >
                          <Trash2 className="w-3.5 h-3.5" />
                        </button>
                      </div>
                    </div>
                  ))}
                </div>
              ) : (
                <div className="p-4 rounded-xl bg-surface-0 border border-glass-border text-center">
                  <p className="text-xs text-text-muted">No API keys yet.</p>
                </div>
              )}

              {/* Generate new key */}
              {newKeyValue ? (
                <div className="p-4 rounded-xl bg-accent-cyan/5 border border-accent-cyan/15">
                  <p className="text-xs font-semibold text-accent-cyan mb-2">Key generated — copy it now. You won&apos;t see it again.</p>
                  <div className="flex items-center gap-2">
                    <code className="flex-1 text-xs font-mono bg-surface-0 px-3 py-2 rounded-lg border border-glass-border text-text-primary break-all">
                      {newKeyValue}
                    </code>
                    <button
                      onClick={() => { navigator.clipboard.writeText(newKeyValue); toast.success('Copied!'); }}
                      className="px-3 py-2 text-xs flex items-center gap-1 shrink-0 rounded-lg bg-surface-1 border border-surface-3 text-text-secondary hover:text-text-primary hover:border-accent-cyan/40 transition"
                    >
                      <Copy className="w-3.5 h-3.5" /> Copy
                    </button>
                  </div>
                  <button
                    onClick={() => { setNewKeyValue(null); setKeyNameInput(''); }}
                    className="text-xs text-text-muted mt-2 hover:text-text-primary transition"
                  >
                    Dismiss
                  </button>
                </div>
              ) : (
                <div className="flex items-center gap-2">
                  <FlatInput
                    type="text" value={keyNameInput}
                    onChange={e => setKeyNameInput(e.target.value)}
                    placeholder="e.g. My script"
                    className="flex-1 text-sm"
                  />
                  <CriticalButton
                    onClick={async () => {
                      if (!keyNameInput.trim()) { toast.error('Enter a name'); return; }
                      setCreatingKey(true);
                      try {
                        const res = await createApiKey(keyNameInput.trim());
                        setNewKeyValue(res.key);
                        setApiKeys(prev => [...prev, { id: '', name: res.name, key_prefix: res.key_prefix, created_at: new Date().toISOString(), last_used_at: null }]);
                        toast.success('API key created');
                      } catch { toast.error('Failed to create key'); } finally { setCreatingKey(false); }
                    }}
                    loading={creatingKey}
                  >
                    {!creatingKey && <Plus className="w-4 h-4" />}
                    Generate
                  </CriticalButton>
                </div>
              )}
            </div>
          )}
        </motion.section>

        {/* ── Data & Privacy ── */}
        <motion.section variants={fadeUp} className="glass-card p-6">
          <div className="flex items-center gap-2 mb-4">
            <Shield className="w-4 h-4 text-accent-cyan" />
            <h2 className="text-base font-semibold text-text-primary">Data & Privacy</h2>
          </div>
          <div className="space-y-3">
            {[
              'Your uploaded sequences and results belong to you. We never train models on your data.',
              'Cached query results are stored for 24 hours, keyed by input hash — not your user ID.',
              'All AI outputs are labeled "AI-assisted research analysis — not for clinical or diagnostic use."',
            ].map((line, i) => (
              <div key={i} className="flex items-start gap-2.5">
                <div className="w-1 h-1 rounded-full bg-accent-cyan/60 mt-2 shrink-0" />
                <p className="text-sm text-text-secondary">{line}</p>
              </div>
            ))}
          </div>
        </motion.section>

        {/* ── Account Actions ── */}
        <motion.section variants={fadeUp} className={`glass-card p-6 ${isGuest ? '' : 'border border-error/10'}`}>
          <h2 className="text-base font-semibold text-text-primary mb-4">
            {isGuest ? 'Get Started' : 'Account Actions'}
          </h2>
          {isGuest ? (
            <div className="space-y-3">
              <p className="text-sm text-text-secondary">
                Sign in with Google to save your results, access your history, and unlock higher daily limits.
              </p>
              <CriticalButton onClick={() => upgradeToAccount()}>
                <svg className="w-4 h-4" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2"><path d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92a5.06 5.06 0 0 1-2.2 3.32v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.1z"/><path d="M12 23c2.97 0 5.46-.98 7.28-2.66l-3.57-2.77c-.98.66-2.23 1.06-3.71 1.06-2.86 0-5.29-1.93-6.16-4.53H2.18v2.84C3.99 20.53 7.7 23 12 23z"/><path d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z"/><path d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z"/></svg>
                Sign in with Google
              </CriticalButton>
            </div>
          ) : (
            <button
              onClick={handleSignOut}
              className="flex items-center gap-2 px-4 py-2.5 rounded-xl border border-error/20 text-error text-sm hover:bg-error/5 transition"
            >
              <LogOut className="w-4 h-4" />
              Sign out
            </button>
          )}
        </motion.section>
      </motion.div>
    </div>
  );
}