# Copyright Sage Vaillancourt 2021

import os
import subprocess
from dataclasses import dataclass

from flask import send_from_directory, Response


def get_unique():
    import uuid
    unique = str(uuid.uuid1().hex)
    return unique


def get_datetime():
    from datetime import datetime
    now = datetime.now()
    return now.strftime("%Y-%m-%d %H:%M:%S")


root_dir = os.path.dirname(os.getcwd())
proj_dir = root_dir + '/undercover/'
output_dir = proj_dir + 'outputs/'
base_tex_text = open(proj_dir + "/letter_templates/base.tex", "r").read()


@dataclass
class CLData:
    selectedLetter: int  # Metadata

    username: str
    company: str
    jobAndPronoun: str
    skillTypes: str
    mySkills: str
    closingText: str
    body: str

    def get_pairs(self):
        return [
            ("username", self.username),
            ("company", self.company),
            ("jobAndPronoun", self.jobAndPronoun),
            ("skillTypes", self.skillTypes),
            ("mySkills", self.mySkills),
            ("closingText", self.closingText),
            ("body", self.body),
        ]

    def generate_pdf(self) -> Response:
        """
        :return: Response when successful
        :raise ValueError: e.args[0] is a list of error strings, if generation fails
        """
        import threading
        unique_id = get_unique()
        unique_file = output_dir + unique_id + ".tex"
        f = open(unique_file, "w")
        for pair in self.get_pairs():
            f.write("\\def \\" + pair[0] + "{" + pair[1] + "}\n")
        f.write(base_tex_text)
        f.close()

        output_arg = "-jobname=outputs/" + unique_id + " " + unique_file
        com = "pdflatex -halt-on-error " + output_arg
        build_text = "[" + get_datetime() + "] Building for " + unique_id + " "
        result = subprocess.run(
            ['bash', '-c', com],
            stdout=subprocess.PIPE,
            text=True
        )

        if result.returncode == 0:
            print(build_text + "[SUCCESS]")

            result = subprocess.run(
                [
                    'gs',
                    '-sDEVICE=pdfwrite',
                    '-dCompatibilityLevel=1.5',
                    '-dNOPAUSE',
                    '-dQUIET',
                    '-dBATCH',
                    '-dPrinted=false',
                    '-sOutputFile=outputs/' + unique_id + '.compressed.pdf',
                    'outputs/' + unique_id + '.pdf'
                ],
                stdout=subprocess.PIPE,
                text=True
            )

            threading.Timer(60 * 5, cleanup, [output_dir + unique_id]).start()

            output_file = unique_id
            if result.returncode == 0:
                output_file += ".compressed.pdf"
            else:
                output_file += ".pdf"

            return send_from_directory(
                output_dir,
                output_file,
                download_name=self.username.replace(" ", "") + "_CoverLetter.pdf",
                as_attachment=True
            )
        else:
            print(build_text + "[FAIL]")
            # Collect output but delete boilerplate text
            errors = list(map(str.strip, result.stdout.split("\n")))
            del errors[:13]
            del errors[-2:]
            raise ValueError(errors)


def cleanup(unique):
    subprocess.run(['bash', '-c', "rm " + unique + ".*"])