#!/usr/bin/env python3
"""Smol listing manager."""

import string
import subprocess
from pathlib import Path

import smolcgi as scgi
scgi.require_client_cert()

ALLOWED_LIST_NAME_CHARS = string.ascii_lowercase + string.digits + "_"


def show_lists():
    user_dir = scgi.get_user_dir()
    scgi.header(20, "text/gemini")
    print("# Lists")
    for child in user_dir.iterdir():
        if child.is_file():
            scgi.link(f"/{child.name}", f"📄 {child.name}")
    scgi.link("/_/create", "✨ Create a new list")


def show_list(list_name):
    list_file = scgi.get_user_dir() / list_name
    try:
        with open(list_file, "rt") as f:
            content = f.read()
    except FileNotFoundError:
        scgi.not_found()
    else:
        scgi.header(20, "text/gemini")
        print("# " + list_name)
        print(content)
        scgi.link(f"/{list_name}/add", "Append item")
        scgi.link(f"/{list_name}/pop", "Pop first item")
        scgi.link(f"/{list_name}/clear", "Clear list")
        scgi.link(f"/{list_name}/delete", "Delete list")


def process_action(list_name, action):
    if list_name == "_":
        if action == "create":
            process_creation()
        else:
            scgi.not_found()
    else:
        if action == "add":
            process_add(list_name)
        elif action == "pop":
            process_pop(list_name)
        elif action == "clear":
            process_clear(list_name)
        elif action == "delete":
            process_delete(list_name)
        else:
            scgi.not_found()


def process_creation():
    if not (new_list_name := scgi.query_string_dec):
        meta = "List name (allowed chars: lowercase, digits, underscore)"
        scgi.require_input(meta)
    else:
        for char in new_list_name:
            if char not in ALLOWED_LIST_NAME_CHARS:
                scgi.temp_error(f"Illegal character in list name: {char}")
        list_file = scgi.get_user_dir() / new_list_name
        list_file.touch(mode=0o660)
        redirect_to_list(new_list_name)


def process_add(list_name):
    if not (item := scgi.query_string_dec):
        scgi.require_input("Enter your item")
    else:
        if "\n" in item:
            scgi.temp_error("No new line allowed in item.")
        line = f"* {item}\n"
        list_file = scgi.get_user_dir() / list_name
        try:
            with open(list_file, "at") as f:
                f.write(line)
        except FileNotFoundError:
            scgi.not_found()
        else:
            redirect_to_list(list_name)


def process_pop(list_name):
    list_file = scgi.get_user_dir() / list_name
    subprocess.run(["sed", "-i", "1d", str(list_file)])
    redirect_to_list(list_name)


def process_clear(list_name):
    if scgi.query_string_dec:
        if scgi.query_string_dec != list_name:
            redirect_to_list(list_name)
        list_file = scgi.get_user_dir() / list_name
        try:
            with open(list_file, "wt") as f:
                f.truncate()
        except OSError:
            scgi.temp_error()
        redirect_to_list(list_name)
    else:
        scgi.require_input("Type the list name to confirm its clearing.")


def process_delete(list_name):
    if scgi.query_string_dec:
        if scgi.query_string_dec != list_name:
            redirect_to_list(list_name)
        list_file = scgi.get_user_dir() / list_name
        list_file.unlink()
        scgi.redirect_temp(scgi.script_name)
    else:
        scgi.require_input("Type the list name to confirm its deletion.")


def redirect_to_list(list_name):
    scgi.redirect_temp(scgi.script_name + "/" + list_name)


path_components = scgi.path_info.lstrip("/").split("/", maxsplit=1)
list_name = path_components[0]
action = path_components[1] if len(path_components) > 1 else ''
if not list_name:
    show_lists()
elif not action and list_name != "_":
    show_list(list_name)
else:
    process_action(list_name, action)