#!/usr/bin/env python
# format:
# $ nix run nixpkgs#python3Packages.black -- update.py
# type-check:
# $ nix run nixpkgs#python3Packages.mypy -- update.py
# linted:
# $ nix run nixpkgs#python3Packages.flake8 -- --ignore E501,E265,E402 update.py

import inspect
import os
import tempfile
import shutil
from dataclasses import dataclass
import subprocess
import csv
import logging
import textwrap
from multiprocessing.dummy import Pool
import pluginupdate
from pluginupdate import update_plugins, FetchConfig

from typing import List, Tuple, Optional
from pathlib import Path

log = logging.getLogger()
log.addHandler(logging.StreamHandler())

ROOT = Path(os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))).parent.parent  # type: ignore

PKG_LIST = "maintainers/scripts/luarocks-packages.csv"
TMP_FILE = "$(mktemp)"
GENERATED_NIXFILE = "pkgs/development/lua-modules/generated-packages.nix"

HEADER = """/* {GENERATED_NIXFILE} is an auto-generated file -- DO NOT EDIT!
Regenerate it with: nix run nixpkgs#luarocks-packages-updater
You can customize the generated packages in pkgs/development/lua-modules/overrides.nix
*/
""".format(
    GENERATED_NIXFILE=GENERATED_NIXFILE
)

FOOTER = """
}
/* GENERATED - do not edit this file */
"""


@dataclass
class LuaPlugin:
    name: str
    """Name of the plugin, as seen on luarocks.org"""
    rockspec: str
    """Full path towards the rockspec"""
    ref: Optional[str]
    """git reference (branch name/tag)"""
    version: Optional[str]
    """Set it to pin a package """
    server: Optional[str]
    """luarocks.org registers packages under different manifests.
    Its value can be 'http://luarocks.org/dev'
    """
    luaversion: Optional[str]
    """Attribue of the lua interpreter if a package is available only for a specific lua version"""
    maintainers: Optional[str]
    """ Optional string listing maintainers separated by spaces"""

    @property
    def normalized_name(self) -> str:
        return self.name.replace(".", "-")


# rename Editor to LangUpdate/ EcosystemUpdater
class LuaEditor(pluginupdate.Editor):

    def create_parser(self):
        parser = super().create_parser()
        parser.set_defaults(proc=1)
        return parser

    def get_current_plugins(self):
        return []

    def load_plugin_spec(self, input_file) -> List[LuaPlugin]:
        luaPackages = []
        csvfilename = input_file
        log.info("Loading package descriptions from %s", csvfilename)

        with open(csvfilename, newline="") as csvfile:
            reader = csv.DictReader(
                csvfile,
            )
            for row in reader:
                # name,server,version,luaversion,maintainers
                plugin = LuaPlugin(**row)
                luaPackages.append(plugin)
        return luaPackages

    def update(self, args):
        update_plugins(self, args)

    def generate_nix(self, results: List[Tuple[LuaPlugin, str]], outfilename: str):
        with tempfile.NamedTemporaryFile("w+") as f:
            f.write(HEADER)
            header2 = textwrap.dedent(
                """
                { stdenv, lib, fetchurl, fetchgit, callPackage, ... }:
                final: prev:
                {
            """
            )
            f.write(header2)
            for plugin, nix_expr in results:
                f.write(f"{plugin.normalized_name} = {nix_expr}")
            f.write(FOOTER)
            f.flush()

            # if everything went fine, move the generated file to its destination
            # using copy since move doesn't work across disks
            shutil.copy(f.name, outfilename)

        print(f"updated {outfilename}")

    @property
    def attr_path(self):
        return "luaPackages"

    def get_update(self, input_file: str, outfile: str, config: FetchConfig):
        _prefetch = generate_pkg_nix

        def update() -> dict:
            plugin_specs = self.load_plugin_spec(input_file)
            sorted_plugin_specs = sorted(plugin_specs, key=lambda v: v.name.lower())

            try:
                pool = Pool(processes=config.proc)
                results = pool.map(_prefetch, sorted_plugin_specs)
            finally:
                pass

            self.generate_nix(results, outfile)

            redirects = {}
            return redirects

        return update

    def rewrite_input(self, input_file: str, *args, **kwargs):
        # vim plugin reads the file before update but that shouldn't be our case
        # not implemented yet
        # fieldnames = ['name', 'server', 'version', 'luaversion', 'maintainers']
        # input_file = "toto.csv"
        # with open(input_file, newline='') as csvfile:
        #     writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
        #     writer.writeheader()
        #     for row in reader:
        #         # name,server,version,luaversion,maintainers
        #         plugin = LuaPlugin(**row)
        #         luaPackages.append(plugin)
        pass


def generate_pkg_nix(plug: LuaPlugin):
    """
    Generate nix expression for a luarocks package
    Our cache key associates "p.name-p.version" to its rockspec
    """
    log.debug("Generating nix expression for %s", plug.name)

    cmd = ["luarocks", "nix"]

    if plug.maintainers:
        cmd.append(f"--maintainers={plug.maintainers}")

    if plug.rockspec != "":
        if plug.ref or plug.version:
            msg = (
                "'version' and 'ref' will be ignored as the rockspec is hardcoded for package %s"
                % plug.name
            )
            log.warning(msg)

        log.debug("Updating from rockspec %s", plug.rockspec)
        cmd.append(plug.rockspec)

    # update the plugin from luarocks
    else:
        cmd.append(plug.name)
        if plug.version and plug.version != "src":
            cmd.append(plug.version)

    if plug.server != "src" and plug.server:
        cmd.append(f"--only-server={plug.server}")

    if plug.luaversion:
        cmd.append(f"--lua-version={plug.luaversion}")
        luaver = plug.luaversion.replace('.', '')
        if luaver := os.getenv(f"LUA_{luaver}"):
            cmd.append(f"--lua-dir={luaver}")

    log.debug("running %s", " ".join(cmd))

    output = subprocess.check_output(cmd, text=True)
    output = "callPackage(" + output.strip() + ") {};\n\n"
    return (plug, output)


def main():
    editor = LuaEditor(
        "lua",
        ROOT,
        "",
        default_in=PKG_LIST,
        default_out=GENERATED_NIXFILE,
    )

    editor.run()


if __name__ == "__main__":
    main()