"""
Servicio de generación de imágenes para posts.
"""

import os
from typing import Dict, Optional
from pathlib import Path
from html2image import Html2Image
from PIL import Image
from jinja2 import Environment, FileSystemLoader

from app.core.config import settings


class ImageGenerator:
    """Generador de imágenes usando plantillas HTML."""

    def __init__(self):
        self.templates_dir = Path("templates")
        self.output_dir = Path("uploads/generated")
        self.output_dir.mkdir(parents=True, exist_ok=True)

        self.jinja_env = Environment(
            loader=FileSystemLoader(self.templates_dir)
        )

        self._hti = None

    @property
    def hti(self):
        """Lazy initialization de Html2Image."""
        if self._hti is None:
            try:
                self._hti = Html2Image(
                    output_path=str(self.output_dir),
                    custom_flags=['--no-sandbox', '--disable-gpu']
                )
            except FileNotFoundError:
                raise RuntimeError(
                    "Chrome/Chromium no encontrado. Instala Chrome o ejecuta en Docker."
                )
        return self._hti

    def _render_template(self, template_name: str, variables: Dict) -> str:
        """Renderizar una plantilla HTML con variables."""
        template = self.jinja_env.get_template(template_name)
        return template.render(**variables)

    async def generate_tip_card(
        self,
        title: str,
        content: str,
        category: str,
        output_name: str
    ) -> str:
        """Generar imagen de tip tech."""
        variables = {
            "title": title,
            "content": content,
            "category": category,
            "logo_url": f"{settings.BUSINESS_WEBSITE}/logo.png",
            "website": settings.BUSINESS_WEBSITE,
            "business_name": settings.BUSINESS_NAME
        }

        html_content = self._render_template("tip_card.html", variables)

        # Generar imagen
        output_file = f"{output_name}.png"
        self.hti.screenshot(
            html_str=html_content,
            save_as=output_file,
            size=(1080, 1080)
        )

        return str(self.output_dir / output_file)

    async def generate_product_card(
        self,
        name: str,
        price: float,
        image_url: str,
        highlights: list,
        output_name: str
    ) -> str:
        """Generar imagen de producto."""
        variables = {
            "name": name,
            "price": f"${price:,.2f} MXN",
            "image_url": image_url,
            "highlights": highlights[:3],  # Máximo 3 highlights
            "logo_url": f"{settings.BUSINESS_WEBSITE}/logo.png",
            "website": settings.BUSINESS_WEBSITE,
            "business_name": settings.BUSINESS_NAME
        }

        html_content = self._render_template("product_card.html", variables)

        output_file = f"{output_name}.png"
        self.hti.screenshot(
            html_str=html_content,
            save_as=output_file,
            size=(1080, 1080)
        )

        return str(self.output_dir / output_file)

    async def generate_service_card(
        self,
        name: str,
        tagline: str,
        benefits: list,
        icon: str,
        output_name: str
    ) -> str:
        """Generar imagen de servicio."""
        variables = {
            "name": name,
            "tagline": tagline,
            "benefits": benefits[:4],  # Máximo 4 beneficios
            "icon": icon,
            "logo_url": f"{settings.BUSINESS_WEBSITE}/logo.png",
            "website": settings.BUSINESS_WEBSITE,
            "business_name": settings.BUSINESS_NAME
        }

        html_content = self._render_template("service_card.html", variables)

        output_file = f"{output_name}.png"
        self.hti.screenshot(
            html_str=html_content,
            save_as=output_file,
            size=(1080, 1080)
        )

        return str(self.output_dir / output_file)

    async def resize_for_platform(
        self,
        image_path: str,
        platform: str
    ) -> str:
        """Redimensionar imagen para una plataforma específica."""
        sizes = {
            "x": (1200, 675),       # 16:9
            "threads": (1080, 1080), # 1:1
            "instagram": (1080, 1080), # 1:1
            "facebook": (1200, 630)  # ~1.9:1
        }

        target_size = sizes.get(platform, (1080, 1080))

        img = Image.open(image_path)

        # Crear nueva imagen con el tamaño objetivo
        new_img = Image.new('RGB', target_size, (26, 26, 46))  # Color de fondo de la marca

        # Calcular posición para centrar
        img_ratio = img.width / img.height
        target_ratio = target_size[0] / target_size[1]

        if img_ratio > target_ratio:
            # Imagen más ancha
            new_width = target_size[0]
            new_height = int(new_width / img_ratio)
        else:
            # Imagen más alta
            new_height = target_size[1]
            new_width = int(new_height * img_ratio)

        img_resized = img.resize((new_width, new_height), Image.Resampling.LANCZOS)

        # Centrar en la nueva imagen
        x = (target_size[0] - new_width) // 2
        y = (target_size[1] - new_height) // 2
        new_img.paste(img_resized, (x, y))

        # Guardar
        output_path = image_path.replace('.png', f'_{platform}.png')
        new_img.save(output_path, 'PNG', quality=95)

        return output_path


# Instancia global
image_generator = ImageGenerator()