"""
Renders Jinja2 & Sass templates for use by the front end application
"""
# Standard Imports
from pathlib import Path

# Module Imports
import sass
import yaml
import jinja2
import logzero
from logzero import logger
from markdown2 import Markdown
from flask import render_template

# Project Imports
from hyperglass.exceptions import HyperglassError
from hyperglass.configuration import params, devices, logzero_config

# Module Directories
working_directory = Path(__file__).resolve().parent
hyperglass_root = working_directory.parent
file_loader = jinja2.FileSystemLoader(str(working_directory))
env = jinja2.Environment(loader=file_loader)

default_details = {
    "footer": """
---
template: footer
---
By using {{ branding.site_name }}, you agree to be bound by the following terms of \
use: All queries executed on this page are logged for analysis and troubleshooting. \
Users are prohibited from automating queries, or attempting to process queries in \
bulk. This service is provided on a best effort basis, and {{ general.org_name }} \
makes no availability or performance warranties or guarantees whatsoever.
""",
    "bgp_aspath": r"""
---
template: bgp_aspath
title: Supported AS Path Patterns
---
{{ branding.site_name }} accepts the following `AS_PATH` regular expression patterns:

| Expression           | Match                                         |
| :------------------- | :-------------------------------------------- |
| `_65000$`            | Originated by 65000                           |
| `^65000_`            | Received from 65000                           |
| `_65000_`            | Via 65000                                     |
| `_65000_65001_`      | Via 65000 and 65001                           |
| `_65000(_.+_)65001$` | Anything from 65001 that passed through 65000 |
""",
    "bgp_community": """
---
template: bgp_community
title: BGP Communities
---
{{ branding.site_name }} makes use of the following BGP communities:

| Community | Description |
| :-------- | :---------- |
| `65000:1` | Example 1   |
| `65000:2` | Example 2   |
| `65000:3` | Example 3   |
""",
}

default_info = {
    "bgp_route": """
---
template: bgp_route
---
Performs BGP table lookup based on IPv4/IPv6 prefix.
""",
    "bgp_community": """
---
template: bgp_community
link: <a href="#" id="helplink_bgpc">{{ general.org_name }} BGP Communities</a>
---
Performs BGP table lookup based on [Extended](https://tools.ietf.org/html/rfc4360) \
or [Large](https://tools.ietf.org/html/rfc8195) community value.

{{ info["link"] }}
""",
    "bgp_aspath": """
---
template: bgp_aspath
link: <a href="#" id="helplink_bgpa">Supported BGP AS Path Expressions</a>
---
Performs BGP table lookup based on `AS_PATH` regular expression.

{{ info["link"] }}
""",
    "ping": """
---
template: ping
---
Sends 5 ICMP echo requests to the target.
""",
    "traceroute": """
---
template: traceroute
---
Performs UDP Based traceroute to the target.<br>For information about how to \
interpret traceroute results, [click here]\
(https://hyperglass.readthedocs.io/en/latest/assets/traceroute_nanog.pdf).
""",
}


def generate_markdown(section, file_name):
    if section == "info":
        file = working_directory.joinpath(f"templates/info/{file_name}.md")
        defaults = default_info
    elif section == "details":
        file = working_directory.joinpath(f"templates/info/details/{file_name}.md")
        defaults = default_details
    if file.exists():
        with file.open(mode="r") as file_raw:
            yaml_raw = file_raw.read()
    else:
        yaml_raw = defaults[file_name]
        logger.error(yaml_raw.split("---", 2))
    _, frontmatter, content = yaml_raw.split("---", 2)
    html_classes = {"table": "table"}
    markdown = Markdown(
        extras={
            "break-on-newline": True,
            "code-friendly": True,
            "tables": True,
            "html-classes": html_classes,
        }
    )
    frontmatter_rendered = (
        jinja2.Environment(loader=jinja2.BaseLoader)
        .from_string(frontmatter)
        .render(params)
    )
    if frontmatter_rendered:
        frontmatter_loaded = yaml.safe_load(frontmatter_rendered)
    elif not frontmatter_rendered:
        frontmatter_loaded = {"frontmatter": None}
    content_rendered = (
        jinja2.Environment(loader=jinja2.BaseLoader)
        .from_string(content)
        .render(params, info=frontmatter_loaded)
    )
    help_dict = dict(content=markdown.convert(content_rendered), **frontmatter_loaded)
    if not help_dict:
        raise HyperglassError(f"Error reading YAML frontmatter for {file_name}")
    return help_dict


def html(template_name):
    """Renders Jinja2 HTML templates"""
    details_name_list = ["footer", "bgp_aspath", "bgp_community"]
    details_dict = {}
    for details_name in details_name_list:
        details_data = generate_markdown("details", details_name)
        details_dict.update({details_name: details_data})
    info_list = ["bgp_route", "bgp_aspath", "bgp_community", "ping", "traceroute"]
    info_dict = {}
    for info_name in info_list:
        info_data = generate_markdown("info", info_name)
        info_dict.update({info_name: info_data})
    try:
        template_file = f"templates/{template_name}.html.j2"
        template = env.get_template(template_file)
        return template.render(
            params, info=info_dict, details=details_dict, networks=devices.networks
        )
    except jinja2.TemplateNotFound as template_error:
        logger.error(
            f"Error rendering Jinja2 template {Path(template_file).resolve()}."
        )
        raise HyperglassError(template_error)


def css():
    """Renders Jinja2 template to Sass file, then compiles Sass as CSS"""
    scss_file = hyperglass_root.joinpath("static/sass/hyperglass.scss")
    css_file = hyperglass_root.joinpath("static/css/hyperglass.css")
    # Renders Jinja2 template as Sass file
    try:
        template_file = "templates/hyperglass.scss.j2"
        template = env.get_template(template_file)
        rendered_output = template.render(params)
        with scss_file.open(mode="w") as scss_output:
            scss_output.write(rendered_output)
    except jinja2.TemplateNotFound as template_error:
        logger.error(
            f"Error rendering Jinja2 template {Path(template_file).resolve()}."
        )
        raise HyperglassError(template_error)
    # Compiles Sass to CSS
    try:
        generated_sass = sass.compile(filename=str(scss_file))
        with css_file.open(mode="w") as css_output:
            css_output.write(generated_sass)
            logger.debug(f"Compiled Sass file {scss_file} to CSS file {css_file}.")
    except:
        logger.error(f"Error compiling Sass in file {scss_file}.")
        raise