import type { Genome } from './genome';
import type { EvolutionConfig } from './evolution';

/**
 * Export/Import system for trained genomes.
 * 
 * Allows saving champion genomes as JSON files and loading them back
 * for exhibition matches or continued training.
 */

export interface ExportedGenome {
    version: string;
    timestamp: number;
    config: {
        inputCount: number;
        outputCount: number;
    };
    genome: Genome;
    metadata?: {
        generation?: number;
        fitness?: number;
        speciesCount?: number;
    };
}

const EXPORT_VERSION = '1.0.0';

/**
 * Export a genome to a downloadable JSON format
 */
export function exportGenome(
    genome: Genome,
    config: EvolutionConfig,
    metadata?: ExportedGenome['metadata']
): ExportedGenome {
    return {
        version: EXPORT_VERSION,
        timestamp: Date.now(),
        config: {
            inputCount: config.inputCount,
            outputCount: config.outputCount,
        },
        genome: {
            id: genome.id,
            nodes: genome.nodes,
            connections: genome.connections,
            fitness: genome.fitness,
        },
        metadata,
    };
}

/**
 * Import a genome from JSON
 */
export function importGenome(exported: ExportedGenome): {
    genome: Genome;
    config: { inputCount: number; outputCount: number };
} {
    // Version check
    if (exported.version !== EXPORT_VERSION) {
        console.warn(`Imported genome version ${exported.version} may be incompatible with current version ${EXPORT_VERSION}`);
    }
    
    return {
        genome: exported.genome,
        config: exported.config,
    };
}

/**
 * Download genome as JSON file
 */
export function downloadGenomeAsFile(exported: ExportedGenome, filename?: string): void {
    const json = JSON.stringify(exported, null, 2);
    const blob = new Blob([json], { type: 'application/json' });
    const url = URL.createObjectURL(blob);
    
    const link = document.createElement('a');
    link.href = url;
    link.download = filename || `neat-champion-${Date.now()}.json`;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    
    URL.revokeObjectURL(url);
}

/**
 * Upload and parse genome from file
 */
export function uploadGenomeFromFile(): Promise<ExportedGenome> {
    return new Promise((resolve, reject) => {
        const input = document.createElement('input');
        input.type = 'file';
        input.accept = 'application/json,.json';
        
        input.onchange = (e) => {
            const file = (e.target as HTMLInputElement).files?.[0];
            if (!file) {
                reject(new Error('No file selected'));
                return;
            }
            
            const reader = new FileReader();
            reader.onload = (event) => {
                try {
                    const json = event.target?.result as string;
                    const exported = JSON.parse(json) as ExportedGenome;
                    resolve(exported);
                } catch (err) {
                    reject(new Error('Failed to parse genome file'));
                }
            };
            reader.onerror = () => reject(new Error('Failed to read file'));
            reader.readAsText(file);
        };
        
        input.click();
    });
}