import { Injectable } from '@angular/core';
import { CapacitorHttp, CapacitorCookies, HttpResponse } from '@capacitor/core';
import { Filesystem, Directory } from '@capacitor/filesystem';
import { FileOpener } from '@capacitor-community/file-opener';
import { AuthService } from './auth.service';

@Injectable({ providedIn: 'root' })
export class SiuService {
    constructor(private authService: AuthService) {}
    private readonly BASE_URL = 'https://autogestion.udelaciudad.edu.ar/caba';

    async getAcademicHistory(dni: string, pass: string, carreraId: string = '30'): Promise<any[]> {
        try {
            const authCookies = await this.authenticateSiu(dni, pass);
            const sessionCookies = await this.selectCareer(carreraId, authCookies);

            // 3. OBTENER PLAN DE ESTUDIO
            const { html: rawHtml } = await this.getHtml(`${this.BASE_URL}/plan_estudio`, sessionCookies);

            if (!rawHtml) {
                throw new Error('No se recibió contenido del plan de estudios.');
            }

            const regex = /on_arrival\((\{.*?"id":"info_plan".*?\})\);/s;
            const match = rawHtml.match(regex);

            if (match && match[1]) {
                const jsonData = JSON.parse(match[1]);
                const contentHtml = jsonData.content;
                return this.parseHtmlSubjects(contentHtml);
            }

            if (rawHtml.includes('acceso?auth=form') || rawHtml.includes('id="login"')) {
                throw new Error('La sesión de SIU Guaraní no se pudo autenticar o expiró.');
            }

            throw new Error('No se encontró el bloque de materias');
        } catch (error) {
            console.error('Error SIU Academic History:', error);
            throw error;
        }
    }

    async getInscripcionesActivas(dni: string, pass: string, carreraId: string = '30'): Promise<any[]> {
        try {
            const authCookies = await this.authenticateSiu(dni, pass);
            const sessionCookies = await this.selectCareer(carreraId, authCookies);

            // OBTENER PÁGINA DE CURSADA
            const { html: rawHtml } = await this.getHtml(`${this.BASE_URL}/cursada`, sessionCookies);

            if (!rawHtml) return [];
            
            // 1. Extraer directamente de "notificaciones" donde SIU provee el array JSON "asignaciones"
            const regexNotif = /on_arrival\((\{.*?"id":"notificaciones".*?\})\);/s;
            const matchNotif = rawHtml.match(regexNotif);
            if (matchNotif && matchNotif[1]) {
                try {
                    const jsonNotif = JSON.parse(matchNotif[1]);
                    const asignaciones = jsonNotif.info?.asignaciones;
                    if (Array.isArray(asignaciones) && asignaciones.length > 0) {
                        return asignaciones.map((asig: any) => ({
                            nombre: asig.NOMBRE_MATERIA || asig.MATERIA,
                            codigo: asig.NOMBRE || asig.MATERIA, // ej: "ASIG00127-E1-TD"
                            comision: asig.COMISION,
                            dia: asig.DIA_SEMANA
                        }));
                    }
                } catch (e) {
                    console.warn('No se pudieron leer asignaciones estructuradas:', e);
                }
            }

            // 2. Fallback: extraer del bloque HTML "info_materia" (tabla .js-mis-inscripciones)
            const regex = /on_arrival\((\{.*?"id":"info_materia".*?\})\);/s;
            const match = rawHtml.match(regex);

            if (match && match[1]) {
                const jsonData = JSON.parse(match[1]);
                const contentHtml = jsonData.content;
                return this.parseInscripcionesActivasHtml(contentHtml);
            }

            return [];
        } catch (error) {
            console.error('Error SIU Active Inscriptions:', error);
            return [];
        }
    }

    private async authenticateSiu(dni: string, pass: string): Promise<string> {
        console.log('Autenticando en SIU...');
        const loginData = `usuario=${encodeURIComponent(dni)}&password=${encodeURIComponent(pass)}&login=Ingresar`;
        const headers = this.getCommonHeaders();
        headers['Content-Type'] = 'application/x-www-form-urlencoded';

        const resLogin: HttpResponse = await CapacitorHttp.post({
            url: `${this.BASE_URL}/acceso?auth=form`,
            data: loginData,
            headers
        });

        let cookies = this.extractCookies(resLogin.headers);
        const stored = await this.getStoredCookies();
        cookies = this.mergeCookieStrings(cookies, stored);

        const dataStr = this.decodeResponseData(resLogin.data);

        if (dataStr && (dataStr.includes('El usuario o la contraseña no son correctos') || dataStr.includes('error-login') || dataStr.includes('login_error'))) {
            throw new Error('DNI o Contraseña incorrectos en SIU Guaraní.');
        }

        return cookies;
    }

    private async selectCareer(carreraId: string, currentCookies: string): Promise<string> {
        console.log('Seleccionando carrera:', carreraId);
        const resCambio = await this.getHtml(`${this.BASE_URL}/acceso/cambiar_carrera?id=${carreraId}&op=inicio_alumno`, currentCookies);
        const resInicio = await this.getHtml(`${this.BASE_URL}/inicio_alumno`, resCambio.cookies);
        return resInicio.cookies;
    }

    private async getHtml(url: string, cookies: string): Promise<{ html: string; cookies: string }> {
        let updatedCookies = cookies;
        const res: HttpResponse = await CapacitorHttp.get({
            url,
            headers: this.getCommonHeaders(updatedCookies)
        });

        updatedCookies = this.mergeCookies(updatedCookies, res.headers);
        const stored = await this.getStoredCookies();
        updatedCookies = this.mergeCookieStrings(updatedCookies, stored);

        let html = this.decodeResponseData(res.data);

        // Fallback: si html es nulo/vacío por codificación no-UTF8 (ej. ISO-8859-1 en SIU), solicitar arraybuffer y decodificar
        if (!html) {
            console.log(`Reintentando ${url} con arraybuffer para decodificación ISO-8859-1...`);
            const resBuffer: HttpResponse = await CapacitorHttp.get({
                url,
                responseType: 'arraybuffer',
                headers: this.getCommonHeaders(updatedCookies)
            });
            updatedCookies = this.mergeCookies(updatedCookies, resBuffer.headers);
            html = this.decodeBase64Response(resBuffer.data);
        }

        return { html, cookies: updatedCookies };
    }

    private decodeResponseData(data: any): string {
        if (typeof data === 'string') {
            return data;
        }
        if (data && typeof data === 'object') {
            return JSON.stringify(data);
        }
        return '';
    }

    private decodeBase64Response(base64: string): string {
        if (!base64 || typeof base64 !== 'string') return '';
        try {
            const binaryString = window.atob(base64);
            const bytes = new Uint8Array(binaryString.length);
            for (let i = 0; i < binaryString.length; i++) {
                bytes[i] = binaryString.charCodeAt(i);
            }
            try {
                const utf8Decoder = new TextDecoder('utf-8', { fatal: true });
                return utf8Decoder.decode(bytes);
            } catch {
                const latinDecoder = new TextDecoder('iso-8859-1');
                return latinDecoder.decode(bytes);
            }
        } catch (e) {
            console.error('Error decoding base64 response:', e);
            return '';
        }
    }

    private async getStoredCookies(): Promise<string> {
        try {
            const cookieMap = await CapacitorCookies.getCookies({ url: this.BASE_URL });
            if (cookieMap && typeof cookieMap === 'object') {
                return Object.entries(cookieMap)
                    .filter(([k, v]) => k && v)
                    .map(([k, v]) => `${k}=${v}`)
                    .join('; ');
            }
        } catch (e) {
            // CapacitorCookies can fail gracefully without breaking flow
        }
        return '';
    }

    private extractTobaContent(html: string, pageletId: string = 'pagelet'): string {
        const regexes = [
            /kernel\.renderer\.on_arrival\((\{.*?\})\);/gs,
            /on_arrival\((\{.*?\})\);/gs
        ];

        for (const regex of regexes) {
            let match;
            // Reset regex index for global searches
            regex.lastIndex = 0;
            while ((match = regex.exec(html)) !== null) {
                try {
                    const jsonData = JSON.parse(match[1]);
                    if (jsonData.id === pageletId || jsonData.info?.id === pageletId) {
                        return jsonData.content || '';
                    }
                } catch (e) { continue; }
            }
        }
        return '';
    }

    async downloadCertificate(dni: string, pass: string): Promise<{ base64: string, filename: string }> {
        console.log('Iniciando descarga de certificado para:', dni);
        try {
            const authCookies = await this.authenticateSiu(dni, pass);
            const sessionCookies = await this.selectCareer('30', authCookies);
            console.log('Login y selección de carrera (ID 30) listos');

            // 1. VALIDAR SI EXISTE UNO VIGENTE (< 30 DÍAS)
            const { html: rawHtmlSolicitudes, cookies: solicitCookies } = await this.getHtml(`${this.BASE_URL}/solicitudes`, sessionCookies);
            console.log('Página de solicitudes obtenida');

            const contentHtmlSolicitudes = this.extractTobaContent(rawHtmlSolicitudes, 'pagelet');
            if (contentHtmlSolicitudes) {
                const existingCert = this.findValidCertificate(contentHtmlSolicitudes);
                if (existingCert) {
                    console.log('Certificado vigente encontrado:', existingCert.filename);
                    return await this.downloadFile(existingCert.url, existingCert.filename, solicitCookies);
                }
            }

            // 2. GENERAR NUEVA SOLICITUD (HEADLESS)
            console.log('No hay certificado vigente o no se pudo leer la tabla. Intentando generar uno nuevo...');
            const { html: rawHtmlGestion, cookies: gestionCookies } = await this.getHtml(`${this.BASE_URL}/solicitudes/solicitud_gestion`, solicitCookies);

            const contentHtmlGestion = this.extractTobaContent(rawHtmlGestion, 'pagelet');
            if (!contentHtmlGestion) {
                console.error('HTML completo de gestión no contiene on_arrival de pagelet. Muestra:', rawHtmlGestion.substring(0, 1000));
                throw new Error('No se pudo localizar el generador (content missing)');
            }

            const parser = new DOMParser();
            const doc = parser.parseFromString(contentHtmlGestion, 'text/html');
            const iframe = doc.querySelector('iframe#frameSolicitud') as HTMLIFrameElement;
            let iframeSrc = iframe?.getAttribute('src');

            if (!iframeSrc) {
                throw new Error('No se pudo localizar el generador (iframe src missing)');
            }

            console.log('Iframe localizado, src:', iframeSrc);
            
            // Asegurar que la URL del iframe es completa
            if (!iframeSrc.startsWith('http')) {
                const baseUrlParsed = new URL(this.BASE_URL);
                iframeSrc = `${baseUrlParsed.origin}${iframeSrc.startsWith('/') ? '' : '/'}${iframeSrc}`;
            }

            // Trigger the print event via URL parameters
            const printUrl = iframeSrc.includes('?') 
                ? `${iframeSrc}&toba_ei_notificar=imprimir` 
                : `${iframeSrc}?toba_ei_notificar=imprimir`;
            
            console.log('Solicitando generación de PDF:', printUrl);
            return await this.downloadFile(printUrl, `Certificado_Alumno_Regular_${new Date().getTime()}.pdf`, gestionCookies);

        } catch (error) {
            console.error('Error detallado en SIU Certificate:', error);
            throw error;
        }
    }

    private findValidCertificate(html: string): { url: string, filename: string } | null {
        const parser = new DOMParser();
        const doc = parser.parseFromString(html, 'text/html');
        const rows = Array.from(doc.querySelectorAll('tr'));

        for (const row of rows) {
            const cells = Array.from(row.querySelectorAll('td'));
            if (cells.length >= 3) {
                const tipo = cells[0].textContent?.trim().toLowerCase() || '';
                const presentarA = cells[2].textContent?.trim().toLowerCase() || '';
                
                // Identificar constancia de alumno regular
                if (tipo.includes('alumno regular')) {
                    const fechaStr = cells[1].textContent?.trim() || ''; 
                    console.log(`Revisando: ${tipo} | Para: ${presentarA} | Fecha: ${fechaStr}`);
                    
                    if (this.isWithin30Days(fechaStr)) {
                        // El usuario indico que si dice "Quien corresponda" o similares (como "Google LLC") sirve.
                        // Solo descartamos si es para un destinatario muy especifico que no sea el solicitado.
                        const downloadLink = row.querySelector('a.descargar_cert, a[href*="descargar_comprobante"]') as HTMLAnchorElement;
                        if (downloadLink) {
                            return {
                                url: downloadLink.getAttribute('href') || '',
                                filename: `Certificado_SIU_${presentarA.replace(/\s+/g, '_')}_${fechaStr.replace(/\//g, '-')}.pdf`
                            };
                        }
                    }
                }
            }
        }
        return null;
    }

    private isWithin30Days(fechaStr: string): boolean {
        // Formato esperado: DD/MM/YYYY
        const parts = fechaStr.split('/');
        if (parts.length !== 3) return false;
        const date = new Date(parseInt(parts[2]), parseInt(parts[1]) - 1, parseInt(parts[0]));
        const diff = new Date().getTime() - date.getTime();
        const days = diff / (1000 * 60 * 60 * 24);
        return days < 30;
    }

    private async downloadFile(url: string, filename: string, cookies?: string): Promise<{ base64: string, filename: string }> {
        // Si la URL es relativa, completarla
        const fullUrl = url.startsWith('http') ? url : `${this.BASE_URL}/${url.startsWith('/') ? url.substring(1) : url}`;
        
        const response: HttpResponse = await CapacitorHttp.get({
            url: fullUrl,
            responseType: 'blob',
            headers: this.getCommonHeaders(cookies)
        });

        return {
            base64: response.data, // CapacitorHttp con responseType blob devuelve base64 string
            filename
        };
    }

    private getCommonHeaders(cookies?: string): Record<string, string> {
        const headers: Record<string, string> = {
            'User-Agent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 17_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148',
            'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
            'Accept-Language': 'es-AR,es;q=0.9'
        };
        if (cookies) {
            headers['Cookie'] = cookies;
        }
        return headers;
    }

    private extractCookies(headers: Record<string, string> | undefined): string {
        return this.mergeCookies('', headers);
    }

    private mergeCookies(existingCookies: string, newHeaders: Record<string, string> | undefined): string {
        if (!newHeaders) return existingCookies;
        const rawSetCookie: string = newHeaders['set-cookie'] || newHeaders['Set-Cookie'] || '';
        if (!rawSetCookie) return existingCookies;

        const cookieMap = new Map<string, string>();
        if (existingCookies) {
            existingCookies.split(';').forEach(c => {
                const [k, ...v] = c.trim().split('=');
                if (k) cookieMap.set(k.trim(), v.join('='));
            });
        }

        const newCookies = rawSetCookie.split(/,(?=[^ ])/);
        newCookies.forEach(c => {
            const cookiePart = c.trim().split(';')[0];
            const [k, ...v] = cookiePart.split('=');
            if (k && v.length > 0) {
                cookieMap.set(k.trim(), v.join('='));
            }
        });

        return Array.from(cookieMap.entries())
            .map(([k, v]) => `${k}=${v}`)
            .join('; ');
    }

    private mergeCookieStrings(cookies1: string, cookies2: string): string {
        if (!cookies1) return cookies2 || '';
        if (!cookies2) return cookies1 || '';
        const cookieMap = new Map<string, string>();
        cookies1.split(';').forEach(c => {
            const [k, ...v] = c.trim().split('=');
            if (k) cookieMap.set(k.trim(), v.join('='));
        });
        cookies2.split(';').forEach(c => {
            const [k, ...v] = c.trim().split('=');
            if (k) cookieMap.set(k.trim(), v.join('='));
        });
        return Array.from(cookieMap.entries())
            .map(([k, v]) => `${k}=${v}`)
            .join('; ');
    }

    async saveAndOpenFile(base64Data: string, filename: string): Promise<void> {
        try {
            const savedFile = await Filesystem.writeFile({
                path: `Certificados/${filename}`,
                data: base64Data,
                directory: Directory.Documents,
                recursive: true
            });

            await FileOpener.open({
                filePath: savedFile.uri,
                contentType: 'application/pdf',
            });
        } catch (error) {
            console.error('Error saving or opening file:', error);
            throw error;
        }
    }

    private parseInscripcionesActivasHtml(html: string): any[] {
        const parser = new DOMParser();
        const doc = parser.parseFromString(html, 'text/html');
        // Buscamos los elementos que contienen las inscripciones activas
        const rows = Array.from(doc.querySelectorAll('.js-mis-inscripciones td, .inscripciones-lista td, .cuadro_materias td, table.tabla_cursada td'));
        
        const results: any[] = [];
        for (const td of rows) {
            const text = td.textContent?.trim() || '';
            if (!text || text.length < 5) continue;
            
            // Caso 1: "Nombre Materia - ASIG00127-E1-TD"
            if (text.includes(' - ')) {
                const parts = text.split(' - ');
                const codigo = parts[parts.length - 1].trim();
                const nombre = parts.slice(0, -1).join(' - ').trim();
                if (codigo.toUpperCase().includes('ASIG') || codigo.length >= 4) {
                    results.push({ nombre, codigo });
                    continue;
                }
            }

            // Caso 2: "Nombre Materia (ASIG00127-E1-TD)"
            const matchParen = text.match(/^(.*?)\s*\((ASIG[^\)]+)\)/i);
            if (matchParen) {
                results.push({ nombre: matchParen[1].trim(), codigo: matchParen[2].trim() });
                continue;
            }

            // Caso 3: contiene código ASIG embebido
            const matchAsig = text.match(/(ASIG[A-Z0-9\-_]+)/i);
            if (matchAsig) {
                const codigo = matchAsig[1].trim();
                const nombre = text.replace(codigo, '').replace(/[-–()]/g, '').trim();
                results.push({ nombre, codigo });
            }
        }
        return results;
    }

    private parseHtmlSubjects(html: string): any[] {
        const parser = new DOMParser();
        const doc = parser.parseFromString(html, 'text/html');
        const rows = Array.from(doc.querySelectorAll('tr'));

        return rows.map(row => {
            const cols = row.querySelectorAll('td');
            if (cols.length >= 6) {
                const nombreRaw = cols[0].textContent?.trim() || '';
                return {
                    nombre: nombreRaw.split(' (')[0],
                    nota: cols[4].textContent?.trim(),
                    origen: cols[5].textContent?.trim()
                };
            }
            return null;
        }).filter(item => item && item.nombre);
    }
}