import React, { useState } from 'react';
import {
  View,
  Text,
  StyleSheet,
  ScrollView,
  TextInput,
  TouchableOpacity,
  ActivityIndicator,
} from 'react-native';
import { COLORS, FONT_SIZE, SPACING, RADIUS, TEXT, SHADOWS } from '../../../theme';
import { useTheme } from '../../../theme';
import { chatAPI } from '../../../services/api';

interface TestResult {
  question: string;
  response: string;
  confidence_score: number;
  sources: { document_name: string; chunk_text: string; score: number }[];
  model_used: string;
}

export function TestingTab({ chatbotId }: { chatbotId: string }) {
  const { theme } = useTheme();
  const [questions, setQuestions] = useState<string[]>(['']);
  const [results, setResults] = useState<TestResult[]>([]);
  const [expandedIdx, setExpandedIdx] = useState<number | null>(null);
  const [running, setRunning] = useState(false);
  const [error, setError] = useState('');

  const addQuestion = () => {
    if (questions.length < 10) setQuestions(prev => [...prev, '']);
  };

  const updateQuestion = (idx: number, val: string) => {
    setQuestions(prev => prev.map((q, i) => (i === idx ? val : q)));
  };

  const removeQuestion = (idx: number) => {
    setQuestions(prev => prev.filter((_, i) => i !== idx));
  };

  const runTests = async () => {
    const valid = questions.map(q => q.trim()).filter(Boolean);
    if (!valid.length) return;
    setRunning(true);
    setError('');
    setResults([]);
    setExpandedIdx(null);
    try {
      const data = await chatAPI.test(chatbotId, valid);
      setResults(data);
      setExpandedIdx(0);
    } catch (e: any) {
      setError(e?.response?.data?.detail ?? 'Test failed. Please try again.');
    } finally {
      setRunning(false);
    }
  };

  const confidenceColor = (score: number) => {
    if (score >= 0.7) return COLORS.success;
    if (score >= 0.4) return COLORS.warning;
    return COLORS.error;
  };

  return (
    <ScrollView
      style={styles.scroll}
      contentContainerStyle={styles.scrollContent}
      keyboardShouldPersistTaps="handled"
      showsVerticalScrollIndicator={false}>

      <View style={[styles.card, { backgroundColor: theme.surface, borderColor: theme.border }, SHADOWS.sm]}>
        <Text style={[styles.cardTitle, { color: theme.text }]}>Test Questions</Text>
        <Text style={[styles.cardDesc, { color: theme.textSecondary }]}>
          Enter up to 10 questions to test how your chatbot responds.
        </Text>

        {questions.map((q, idx) => (
          <View key={idx} style={styles.questionRow}>
            <Text style={[styles.questionNum, { color: theme.textMuted }]}>{idx + 1}.</Text>
            <TextInput
              style={[styles.questionInput, { backgroundColor: theme.inputBg, borderColor: theme.border, color: theme.text }]}
              value={q}
              onChangeText={val => updateQuestion(idx, val)}
              placeholder="Ask a question..."
              placeholderTextColor={theme.placeholder}
            />
            {questions.length > 1 && (
              <TouchableOpacity onPress={() => removeQuestion(idx)} hitSlop={{ top: 8, bottom: 8, left: 8, right: 8 }}>
                <Text style={styles.removeBtn}>✕</Text>
              </TouchableOpacity>
            )}
          </View>
        ))}

        <View style={styles.actions}>
          {questions.length < 10 && (
            <TouchableOpacity onPress={addQuestion}>
              <Text style={[styles.addBtn, { color: COLORS.primary }]}>+ Add question</Text>
            </TouchableOpacity>
          )}
          <TouchableOpacity
            style={[
              styles.runBtn,
              { backgroundColor: COLORS.primary },
              (running || !questions.some(q => q.trim())) && styles.runBtnDisabled,
            ]}
            onPress={runTests}
            disabled={running || !questions.some(q => q.trim())}>
            {running
              ? <ActivityIndicator size="small" color="#fff" />
              : <Text style={styles.runBtnText}>▶ Run Tests</Text>
            }
          </TouchableOpacity>
        </View>

        {error ? (
          <Text style={[styles.error, { color: COLORS.error }]}>{error}</Text>
        ) : null}
      </View>

      {results.length > 0 && (
        <>
          <Text style={[styles.resultsLabel, { color: theme.textMuted }]}>
            {results.length} RESULT{results.length !== 1 ? 'S' : ''}
          </Text>
          {results.map((r, idx) => (
            <View key={idx} style={[styles.resultCard, { backgroundColor: theme.surface, borderColor: theme.border }, SHADOWS.sm]}>
              <TouchableOpacity
                style={styles.resultHeader}
                onPress={() => setExpandedIdx(expandedIdx === idx ? null : idx)}>
                <View style={[styles.confBadge, { backgroundColor: confidenceColor(r.confidence_score) + '22' }]}>
                  <Text style={[styles.confText, { color: confidenceColor(r.confidence_score) }]}>
                    {Math.round(r.confidence_score * 100)}%
                  </Text>
                </View>
                <Text style={[styles.resultQuestion, { color: theme.text }]} numberOfLines={1}>{r.question}</Text>
                <Text style={[styles.chevron, { color: theme.textMuted }]}>{expandedIdx === idx ? '▲' : '▼'}</Text>
              </TouchableOpacity>

              {expandedIdx === idx && (
                <View style={[styles.resultBody, { borderTopColor: theme.border }]}>
                  <Text style={[styles.responseText, { color: theme.text }]}>{r.response}</Text>

                  {r.sources.length > 0 && (
                    <>
                      <Text style={[styles.sourcesLabel, { color: theme.textMuted }]}>SOURCES</Text>
                      {r.sources.map((src, si) => (
                        <View key={si} style={[styles.sourceChip, { backgroundColor: theme.bgSecondary, borderColor: theme.border }]}>
                          <Text style={[styles.sourceName, { color: theme.textSecondary }]}>
                            {src.document_name}
                            <Text style={{ color: theme.textMuted }}> · {Math.round(src.score * 100)}%</Text>
                          </Text>
                          <Text style={[styles.sourceChunk, { color: theme.textMuted }]} numberOfLines={2}>{src.chunk_text}</Text>
                        </View>
                      ))}
                    </>
                  )}

                  <Text style={[styles.modelLabel, { color: theme.textMuted }]}>Model: {r.model_used}</Text>
                </View>
              )}
            </View>
          ))}
        </>
      )}
    </ScrollView>
  );
}

const styles = StyleSheet.create({
  scroll: { flex: 1 },
  scrollContent: { padding: SPACING.lg, gap: SPACING.lg, paddingBottom: SPACING.xxxl },

  card: {
    borderRadius: RADIUS.xl,
    borderWidth: 1,
    padding: SPACING.lg,
    gap: SPACING.md,
  },
  cardTitle: { ...TEXT.h4 },
  cardDesc: { ...TEXT.small },

  questionRow: { flexDirection: 'row', alignItems: 'center', gap: SPACING.sm },
  questionNum: { width: 18, fontSize: FONT_SIZE.sm, textAlign: 'right' },
  questionInput: {
    flex: 1,
    borderWidth: 1.5,
    borderRadius: RADIUS.md,
    paddingHorizontal: SPACING.md,
    paddingVertical: SPACING.sm,
    fontSize: FONT_SIZE.md,
  },
  removeBtn: { color: '#ccc', fontSize: FONT_SIZE.md, paddingHorizontal: SPACING.xs },

  actions: { flexDirection: 'row', alignItems: 'center', marginTop: SPACING.xs },
  addBtn: { fontSize: FONT_SIZE.sm, fontWeight: '600' },
  runBtn: {
    marginLeft: 'auto',
    flexDirection: 'row',
    alignItems: 'center',
    gap: SPACING.xs,
    borderRadius: RADIUS.md,
    paddingVertical: SPACING.sm,
    paddingHorizontal: SPACING.lg,
    minWidth: 100,
    justifyContent: 'center',
  },
  runBtnDisabled: { opacity: 0.5 },
  runBtnText: { color: COLORS.white, fontSize: FONT_SIZE.sm, fontWeight: '700' },
  error: { fontSize: FONT_SIZE.sm },

  resultsLabel: { fontSize: FONT_SIZE.xs, fontWeight: '700', letterSpacing: 0.8 },

  resultCard: { borderRadius: RADIUS.xl, borderWidth: 1, overflow: 'hidden' },
  resultHeader: { flexDirection: 'row', alignItems: 'center', padding: SPACING.md, gap: SPACING.sm },
  confBadge: { borderRadius: RADIUS.sm, paddingVertical: 3, paddingHorizontal: SPACING.sm },
  confText: { fontSize: FONT_SIZE.xs, fontWeight: '800' },
  resultQuestion: { flex: 1, ...TEXT.smallM },
  chevron: { fontSize: FONT_SIZE.sm },

  resultBody: { borderTopWidth: 1, padding: SPACING.md, gap: SPACING.sm },
  responseText: { ...TEXT.body, lineHeight: 22 },

  sourcesLabel: { fontSize: FONT_SIZE.xs, fontWeight: '700', letterSpacing: 0.8, marginTop: SPACING.xs },
  sourceChip: {
    borderRadius: RADIUS.md,
    borderWidth: 1,
    padding: SPACING.sm,
    gap: 3,
  },
  sourceName: { fontSize: FONT_SIZE.xs, fontWeight: '600' },
  sourceChunk: { fontSize: FONT_SIZE.xs, lineHeight: 16 },
  modelLabel: { fontSize: FONT_SIZE.xs, marginTop: SPACING.xs },
});