/**
 * WordPress dependencies
 */
import { __ } from '@wordpress/i18n';
import { SelectControl, TextareaControl, Button, TextControl } from '@wordpress/components';
import { useState, useEffect } from '@wordpress/element';
import { MediaUpload, MediaUploadCheck } from '@wordpress/block-editor';
import LCPDatasetBuilder from './LCPDatasetBuilder';

const DEFAULT_COLORS = [
    '#FF6384', '#36A2EB', '#FFCE56', '#4BC0C0', '#9966FF',
    '#FF9F40', '#FF6384', '#C9CBCF', '#4BC0C0', '#FF9F40'
];

/**
 * LCPDataSelector Component
 * 
 * @param {Object} props Component properties
 * @param {Object} props.value Current data value
 * @param {Function} props.onChange Callback function when data changes
 * @param {string} props.dataSource Current data source type
 * @param {Function} props.onDataSourceChange Callback function when data source changes
 */
const LCPDataSelector = ({ value, onChange, dataSource, onDataSourceChange }) => {
    const [csvUrl, setCsvUrl] = useState('');
    const [jsonData, setJsonData] = useState('');
    const [error, setError] = useState('');

    // Initialize component state with existing data
    useEffect(() => {
        if (value && Object.keys(value).length > 0) {
            if (dataSource === 'manual_json') {
                setJsonData(JSON.stringify(value, null, 2));
            } else if (dataSource === 'csv_url') {
                const storedUrl = value[Object.keys(value)[0]]?.[0]?.sourceUrl;
                if (storedUrl) {
                    setCsvUrl(storedUrl);
                }
            }
        }
    }, []);

    const dataSourceOptions = [
        { label: __('Manual JSON', 'lcp'), value: 'manual_json' },
        { label: __('CSV Upload', 'lcp'), value: 'csv_upload' },
        { label: __('CSV URL', 'lcp'), value: 'csv_url' },
        { label: __('Dataset Builder', 'lcp'), value: 'dataset_builder' },
    ];

    const validateJsonData = (jsonString) => {
        try {
            const parsed = JSON.parse(jsonString);
            if (typeof parsed !== 'object' || Array.isArray(parsed)) {
                throw new Error('Data must be an object with dataset names as keys');
            }

            // Validate each dataset
            Object.entries(parsed).forEach(([datasetName, dataset]) => {
                if (!Array.isArray(dataset)) {
                    throw new Error(`Dataset "${datasetName}" must be an array`);
                }

                dataset.forEach((item, index) => {
                    if (!item.label || !item.value) {
                        throw new Error(`Item at index ${index} in dataset "${datasetName}" is missing required fields (label or value)`);
                    }
                    // Add default color if not provided
                    if (!item.color) {
                        item.color = DEFAULT_COLORS[index % DEFAULT_COLORS.length];
                    }
                });
            });

            setError('');
            return parsed;
        } catch (e) {
            setError(e.message);
            return null;
        }
    };

    const handleJsonChange = (newJsonData) => {
        setJsonData(newJsonData);
        const validData = validateJsonData(newJsonData);
        if (validData) {
            onChange(validData);
        }
    };

    const handleCsvUpload = (media) => {
        const sourceUrl = media.url;
        fetch(media.url)
            .then(response => response.text())
            .then(csvText => {
                const data = parseCsvToJson(csvText, sourceUrl);
                if (data) {
                    onChange(data);
                }
            })
            .catch(err => {
                setError('Error reading CSV file: ' + err.message);
            });
    };

    const handleCsvUrlChange = (url) => {
        setCsvUrl(url);
        if (url) {
            fetch(url)
                .then(response => response.text())
                .then(csvText => {
                    const data = parseCsvToJson(csvText, url);
                    if (data) {
                        onChange(data);
                    }
                })
                .catch(err => {
                    setError('Error fetching CSV file: ' + err.message);
                });
        }
    };

    const parseCsvToJson = (csvText, sourceUrl = '') => {
        try {
            const lines = csvText.split('\n');
            if (lines.length < 2) {
                throw new Error('CSV must have at least a header row and one data row');
            }

            const headers = lines[0].split(',').map(h => h.trim());
            if (!headers.includes('label') || !headers.includes('value')) {
                throw new Error('CSV must have "label" and "value" columns');
            }

            // Create a single dataset from CSV
            const dataset = lines.slice(1)
                .filter(line => line.trim())
                .map((line, index) => {
                    const values = line.split(',').map(v => v.trim());
                    const item = {};
                    headers.forEach((header, i) => {
                        if (header === 'color' && !values[i]) {
                            item[header] = DEFAULT_COLORS[index % DEFAULT_COLORS.length];
                        } else {
                            item[header] = values[i];
                        }
                    });
                    if (sourceUrl) {
                        item.sourceUrl = sourceUrl;
                    }
                    return item;
                });

            // Create the new data structure
            const data = {
                'Dataset 1': dataset
            };

            setError('');
            return data;
        } catch (e) {
            setError('Error parsing CSV: ' + e.message);
            return null;
        }
    };

    return (
        <div className="lcp-data-selector">
            <SelectControl
                label={__('Data Source', 'lcp')}
                value={dataSource}
                options={dataSourceOptions}
                onChange={onDataSourceChange}
            />

            {dataSource === 'dataset_builder' && (
                <LCPDatasetBuilder
                    value={value}
                    onChange={(newValue) => {
                        onChange(newValue);
                    }}
                />
            )}

            {dataSource === 'manual_json' && (
                <TextareaControl
                    label={__('JSON Data', 'lcp')}
                    help={__('Enter datasets with arrays containing objects with label and value properties. Color is optional.', 'lcp')}
                    value={jsonData}
                    onChange={handleJsonChange}
                    placeholder={`{
  "Dataset 1": [
    {
      "label": "Label 1",
      "value": 100,
      "color": "red"
    },
    {
      "label": "Label 2",
      "value": 200
    }
  ],
  "Dataset 2": [
    {
      "label": "Label 3",
      "value": 300,
      "color": "green"
    }
  ]
}`}
                />
            )}

            {dataSource === 'csv_upload' && (
                <MediaUploadCheck>
                    <MediaUpload
                        onSelect={handleCsvUpload}
                        allowedTypes={['text/csv']}
                        render={({ open }) => (
                            <div>
                                <Button onClick={open} isPrimary>
                                    {__('Upload CSV File', 'lcp')}
                                </Button>
                                {value && Object.keys(value).length > 0 && value[Object.keys(value)[0]]?.[0]?.sourceUrl && (
                                    <div className="current-file" style={{ marginTop: '10px' }}>
                                        {__('Current file:', 'lcp')} {value[Object.keys(value)[0]][0].sourceUrl.split('/').pop()}
                                    </div>
                                )}
                            </div>
                        )}
                    />
                </MediaUploadCheck>
            )}

            {dataSource === 'csv_url' && (
                <TextControl
                    label={__('CSV URL', 'lcp')}
                    value={csvUrl}
                    onChange={handleCsvUrlChange}
                    help={__('Enter URL of a CSV file with label and value columns. Color column is optional.', 'lcp')}
                />
            )}

            {error && (
                <div className="lcp-data-selector-error" style={{ color: 'red', marginTop: '10px' }}>
                    {error}
                </div>
            )}

            {value && Object.keys(value).length > 0 && (
                <div className="data-preview" style={{ marginTop: '15px' }}>
                    <h4>{__('Current Data Preview:', 'lcp')}</h4>
                    <div style={{ fontSize: '12px', color: '#666' }}>
                        {Object.entries(value).map(([datasetName, dataset]) => (
                            <div key={datasetName}>
                                {datasetName}: {dataset.length} {__('data points', 'lcp')}
                            </div>
                        ))}
                    </div>
                </div>
            )}
        </div>
    );
};

export default LCPDataSelector;