# -*- coding: utf-8 -*-
import os
import io
import hashlib
from datetime import datetime
from typing import Optional
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import cm
from reportlab.lib import colors
import streamlit as st

# Credenciais de admin via env (defina no Hugging Face Space Settings)
ADMIN_USER = os.environ.get("ADMIN_USER", "admin")
# Armazena hash sha256 da senha; por padrão 'admin'
_admin_pass_default = os.environ.get("ADMIN_PASS", "admin")
ADMIN_PASS_HASH = hashlib.sha256(_admin_pass_default.encode()).hexdigest()

def ensure_dirs():
    os.makedirs("data", exist_ok=True)
    os.makedirs("data/videos", exist_ok=True)
    os.makedirs("data/pdfs", exist_ok=True)
    os.makedirs("data/certificates", exist_ok=True)

def save_uploaded_file(file, base_dir="data") -> str:
    ensure_dirs()
    filename = file.name
    safe_name = f"{int(datetime.utcnow().timestamp())}_{filename}"
    out_path = os.path.join(base_dir, safe_name)
    with open(out_path, "wb") as f:
        f.write(file.getbuffer())
    return out_path

def human_dt(dt: Optional[datetime]) -> str:
    if not dt:
        return "—"
    return dt.strftime("%d/%m/%Y %H:%M")

def generate_certificate_pdf(student_name: str, course_title: str) -> str:
    ensure_dirs()
    fname = f"cert_{int(datetime.utcnow().timestamp())}.pdf"
    out_path = os.path.join("data/certificates", fname)

    c = canvas.Canvas(out_path, pagesize=A4)
    w, h = A4

    # Moldura simples
    c.setStrokeColor(colors.HexColor("#2c3e50"))
    c.setLineWidth(6)
    c.rect(1*cm, 1*cm, w-2*cm, h-2*cm)

    # Título
    c.setFillColor(colors.HexColor("#2c3e50"))
    c.setFont("Helvetica-Bold", 28)
    c.drawCentredString(w/2, h-5*cm, "CERTIFICADO DE CONCLUSÃO")

    # Texto principal
    c.setFillColor(colors.black)
    c.setFont("Helvetica", 14)
    text = (
        f"Certificamos que {student_name} concluiu com êxito o curso '{course_title}'."
    )
    c.drawCentredString(w/2, h-8*cm, text)

    # Data
    c.setFont("Helvetica-Oblique", 12)
    c.drawCentredString(w/2, h-10*cm, datetime.now().strftime("Emitido em %d/%m/%Y"))

    # Assinatura (placeholder)
    c.line(w/2-5*cm, 4*cm, w/2+5*cm, 4*cm)
    c.setFont("Helvetica", 10)
    c.drawCentredString(w/2, 3.5*cm, "Coordenação — ARM Logística")

    c.showPage()
    c.save()
    return out_path