/**
 * CSV Manager - CRUD operations for CSV files
 * Handles reading, parsing, editing, and saving CSV data
 */

/**
 * Parse CSV text to array of objects
 * @param {string} csvText - CSV content
 * @returns {Array<object>} Parsed data
 */
export function parseCSV(csvText) {
    const lines = csvText.trim().split('\n');
    if (lines.length === 0) return [];
    
    // Get headers
    const headers = lines[0].split(',').map(h => h.trim());
    
    // Parse rows
    const data = [];
    for (let i = 1; i < lines.length; i++) {
        const values = lines[i].split(',').map(v => v.trim());
        const row = {};
        headers.forEach((header, index) => {
            row[header] = values[index] || '';
        });
        data.push(row);
    }
    
    return data;
}

/**
 * Convert array of objects to CSV text
 * @param {Array<object>} data - Data array
 * @returns {string} CSV text
 */
export function toCSV(data) {
    if (data.length === 0) return '';
    
    // Get headers from first object
    const headers = Object.keys(data[0]);
    
    // Create CSV lines
    const lines = [headers.join(',')];
    
    data.forEach(row => {
        const values = headers.map(header => {
            const value = row[header] || '';
            // Escape commas and quotes
            if (value.includes(',') || value.includes('"')) {
                return `"${value.replace(/"/g, '""')}"`;
            }
            return value;
        });
        lines.push(values.join(','));
    });
    
    return lines.join('\n');
}

/**
 * Load CSV file
 * @param {string} filename - CSV filename
 * @returns {Promise<Array<object>>} Parsed data
 */
export async function loadCSV(filename) {
    try {
        const response = await fetch(`BD/${filename}`);
        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`);
        }
        const text = await response.text();
        return parseCSV(text);
    } catch (error) {
        console.error(`Erro ao carregar ${filename}:`, error);
        throw error;
    }
}

/**
 * Download CSV file
 * @param {string} filename - Filename
 * @param {string} csvText - CSV content
 */
export function downloadCSV(filename, csvText) {
    const blob = new Blob([csvText], { type: 'text/csv;charset=utf-8;' });
    const link = document.createElement('a');
    const url = URL.createObjectURL(blob);
    
    link.setAttribute('href', url);
    link.setAttribute('download', filename);
    link.style.visibility = 'hidden';
    
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    
    URL.revokeObjectURL(url);
}

/**
 * Get available CSV files
 * @returns {Array<object>} List of CSV files with metadata
 */
export function getAvailableCSVFiles() {
    return [
        { 
            id: 'perfis_w', 
            name: 'Perfis W', 
            filename: 'perfis_w.csv',
            description: 'Perfis de aço tipo W (vigas)',
            icon: '🏗️'
        },
        { 
            id: 'perfis_i', 
            name: 'Perfis I', 
            filename: 'perfis_i.csv',
            description: 'Perfis de aço tipo I',
            icon: '🏗️'
        },
        { 
            id: 'cantoneiras', 
            name: 'Cantoneiras', 
            filename: 'cantoneiras.csv',
            description: 'Cantoneiras de aço',
            icon: '📐'
        },
        { 
            id: 'tubos_circulares', 
            name: 'Tubos Circulares', 
            filename: 'tubos_circulares.csv',
            description: 'Tubos de seção circular',
            icon: '⭕'
        },
        { 
            id: 'tubos_rhs', 
            name: 'Tubos RHS', 
            filename: 'tubos_rhs.csv',
            description: 'Tubos retangulares/quadrados',
            icon: '⬜'
        },
        { 
            id: 'chapas', 
            name: 'Chapas', 
            filename: 'chapas.csv',
            description: 'Chapas de aço',
            icon: '📄'
        },
        { 
            id: 'barras', 
            name: 'Barras', 
            filename: 'barras.csv',
            description: 'Barras redondas',
            icon: '➖'
        },
        { 
            id: 'eletrodos', 
            name: 'Eletrodos', 
            filename: 'eletrodos.csv',
            description: 'Eletrodos de soldagem',
            icon: '⚡'
        },
        { 
            id: 'parafusos', 
            name: 'Parafusos', 
            filename: 'parafusos.csv',
            description: 'Parafusos estruturais',
            icon: '🔩'
        },
        { 
            id: 'tintas', 
            name: 'Tintas', 
            filename: 'tintas.csv',
            description: 'Tintas e revestimentos',
            icon: '🎨'
        },
        { 
            id: 'acos_soldagem', 
            name: 'Aços - Soldagem', 
            filename: 'Tabela_Acos_Soldagem_Consumiveis.csv',
            description: 'Relação aços e consumíveis',
            icon: '🔥'
        },
        { 
            id: 'acos_pintura', 
            name: 'Aços - Pintura', 
            filename: 'Tabela_Acos_Pintura_Tintas.csv',
            description: 'Relação aços e tintas',
            icon: '🎨'
        }
    ];
}

/**
 * Validate CSV data
 * @param {Array<object>} data - Data to validate
 * @returns {object} Validation result
 */
export function validateCSVData(data) {
    const errors = [];
    
    if (!Array.isArray(data) || data.length === 0) {
        errors.push('Dados vazios ou inválidos');
        return { valid: false, errors };
    }
    
    // Check if all rows have same keys
    const firstKeys = Object.keys(data[0]).sort();
    for (let i = 1; i < data.length; i++) {
        const keys = Object.keys(data[i]).sort();
        if (JSON.stringify(keys) !== JSON.stringify(firstKeys)) {
            errors.push(`Linha ${i + 1}: Colunas inconsistentes`);
        }
    }
    
    // Check for empty required fields (id, nome)
    data.forEach((row, index) => {
        if (!row.id || row.id.trim() === '') {
            errors.push(`Linha ${index + 2}: Campo 'id' vazio`);
        }
        if (!row.nome || row.nome.trim() === '') {
            errors.push(`Linha ${index + 2}: Campo 'nome' vazio`);
        }
    });
    
    return {
        valid: errors.length === 0,
        errors
    };
}