#!/usr/bin/env python3
import csv
import os
import socket
import subprocess
import time
from pathlib import Path
from jinja2 import Environment, FileSystemLoader

LDAPI_SOCKET = "/var/run/slapd/ldapi"
LDIF_DIR = Path("/bootstrap/ldif")
CSV_DIR = Path("/bootstrap/accounts")
INITIALIZED_FLAG = Path("/var/lib/ldap/.initialized")
SLAPD_D = Path("/etc/ldap/slapd.d")


base_dn = os.environ.get("LDAP_BASE_DN") or "dc=example,dc=org"
password = os.environ.get("LDAP_PASSWORD") or "changeit"
tls_enabled = os.environ.get("TLS_ENABLED") == "1"
admin_dn = f"cn=admin,{base_dn}"


def hash_password(password: str) -> str:
    return subprocess.check_output(
        ["slappasswd", "-h", "{SSHA}", "-s", password],
        text=True,
    ).strip()


def run_command(cmd: list, input: str) -> None:
    proc = subprocess.run(cmd, input=input, text=True, capture_output=True, check=False)
    if proc.stdout:
        print(proc.stdout, end="")
    if proc.stderr:
        print(proc.stderr, end="")
    if proc.returncode != 0:
        raise subprocess.CalledProcessError(proc.returncode, proc.args, output=proc.stdout, stderr=proc.stderr)


def apply_ldif(path: Path, env: Environment, command: str = "ldapadd", **ctx) -> None:
    print(f"Applying LDIF: {path.name}")
    rendered = env.get_template(path.name).render(**ctx)
    run_command([command, "-Q", "-Y", "EXTERNAL", "-H", "ldapi:///"], rendered)
    print(f"Finished LDIF: {path.name}")


def wait_for_slapd(timeout: int = 30) -> None:
    for _ in range(timeout):
        try:
            sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
            sock.connect(LDAPI_SOCKET)
            sock.close()
            return
        except OSError:
            time.sleep(1)
    raise RuntimeError("slapd did not become ready in time")


def stop_slapd(proc: subprocess.Popen, timeout: int = 30) -> None:
    proc.terminate()
    try:
        proc.wait(timeout=timeout)
    except subprocess.TimeoutExpired:
        proc.kill()
        proc.wait()


def group_exists(name: str, group_ou: str) -> bool:
    # fmt: off
    result = subprocess.run(
        [
            "ldapsearch", "-Q", "-Y", "EXTERNAL", "-H", "ldapi:///",
            "-b", f"ou={group_ou},{base_dn}", "-s", "one",
            f"(&(objectClass=groupOfNames)(cn={name}))",
            "cn",
        ],
        capture_output=True,
        text=True,
    )
    # fmt: on
    return "numEntries: 1" in result.stdout


def read_users(path: Path, fields: list[str]) -> list[dict]:
    users = []
    with open(path, newline="") as f:
        for row in csv.reader(f):
            if not row or row[0].strip().startswith("#"):
                continue
            users.append(dict(zip(fields, (c.strip() for c in row))))
    return users


def main():
    print("First run — starting initialisation...")
    env = Environment(loader=FileSystemLoader(str(LDIF_DIR)), keep_trailing_newline=True)

    # fmt: off
    proc = subprocess.Popen([
        "slapd",
        "-d", "0",
        "-F", str(SLAPD_D),
        "-u", "openldap",
        "-g", "openldap",
        "-h", "ldapi:///",
    ])
    # fmt: on

    wait_for_slapd()
    print("slapd is ready.")

    apply_ldif(LDIF_DIR / "config-memberof-module.ldif", env)
    apply_ldif(LDIF_DIR / "config-memberof-overlay.ldif", env)
    apply_ldif(LDIF_DIR / "config-indexes.ldif", env)
    apply_ldif(LDIF_DIR / "config-performance.ldif", env)
    apply_ldif(LDIF_DIR / "config-acl.ldif", env, base_dn=base_dn, admin_dn=admin_dn)
    if tls_enabled:
        apply_ldif(LDIF_DIR / "config-tls.ldif", env)

    print("cn=config updated.")

    password_hash = hash_password(password)

    ctx = dict(
        base_dn=base_dn,
        password_hash=password_hash,
    )
    apply_ldif(LDIF_DIR / "base.ldif", env, **ctx)
    apply_ldif(LDIF_DIR / "service-accounts.ldif", env, **ctx)

    # Process optional account CSV files.
    user_files = {
        "users.csv": {
            "name": "users",
            "description": "Regular users",
            "fields": ["uid", "gn", "sn", "mail"],
            "group_ou": "groups",
            "member_ou": "users",
        },
        "admins.csv": {
            "name": "admins",
            "description": "Administrators",
            "fields": ["uid", "gn", "sn", "mail"],
            "group_ou": "privileged-groups",
            "member_ou": "users",
        },
        "posix-users.csv": {
            "name": "users",
            "description": "POSIX users",
            "fields": ["uid", "gn", "sn", "mail", "uidNumber", "gidNumber"],
            "group_ou": "groups",
            "member_ou": "users",
        },
    }

    for filename, group in user_files.items():
        path = CSV_DIR / filename
        if not path.exists():
            # Backward-compatible fallback for older bind-mount layout.
            path = Path("/bootstrap") / filename
        if path.exists():
            print(f'  Reading {group["name"]} from {filename}...')
            users = read_users(path, group["fields"])
            if users:
                ldif = Path(filename).stem + ".ldif"
                for user in users:
                    print(f'  Adding user: {user["uid"]}')
                    apply_ldif(
                        LDIF_DIR / ldif,
                        env,
                        base_dn=base_dn,
                        password_hash=password_hash,
                        **user,
                    )

                uids = [u["uid"] for u in users]
                if group_exists(group["name"], group["group_ou"]):
                    apply_ldif(
                        LDIF_DIR / "add-member.ldif",
                        env,
                        base_dn=base_dn,
                        name=group["name"],
                        group_ou=group["group_ou"],
                        member_ou=group["member_ou"],
                        uids=uids,
                    )
                else:
                    apply_ldif(
                        LDIF_DIR / "group.ldif",
                        env,
                        base_dn=base_dn,
                        name=group["name"],
                        description=group["description"],
                        group_ou=group["group_ou"],
                        member_ou=group["member_ou"],
                        uids=uids,
                    )

    INITIALIZED_FLAG.touch()
    stop_slapd(proc)
    print("Bootstrap complete.")


if __name__ == "__main__":
    main()