use chrono::TimeZone;
use ldap3_proto::{
    proto::LdapOp, LdapFilter, LdapPartialAttribute, LdapResultCode, LdapSearchResultEntry,
};
use tracing::{debug, instrument, warn};

use crate::domain::{
    deserialize::deserialize_attribute_value,
    handler::{UserListerBackendHandler, UserRequestFilter},
    ldap::{
        error::{LdapError, LdapResult},
        utils::{
            expand_attribute_wildcards, get_custom_attribute, get_group_id_from_distinguished_name,
            get_user_id_from_distinguished_name, map_user_field, LdapInfo, UserFieldType,
        },
    },
    schema::{PublicSchema, SchemaUserAttributeExtractor},
    types::{
        AttributeName, AttributeType, GroupDetails, LdapObjectClass, User, UserAndGroups,
        UserColumn, UserId,
    },
};

pub fn get_user_attribute(
    user: &User,
    attribute: &str,
    base_dn_str: &str,
    groups: Option<&[GroupDetails]>,
    ignored_user_attributes: &[AttributeName],
    schema: &PublicSchema,
) -> Option<Vec<Vec<u8>>> {
    let attribute = AttributeName::from(attribute);
    let attribute_values = match map_user_field(&attribute, schema) {
        UserFieldType::ObjectClass => {
            let mut classes = vec![
                b"inetOrgPerson".to_vec(),
                b"posixAccount".to_vec(),
                b"mailAccount".to_vec(),
                b"person".to_vec(),
            ];
            classes.extend(
                schema
                    .get_schema()
                    .extra_user_object_classes
                    .iter()
                    .map(|c| c.as_str().as_bytes().to_vec()),
            );
            classes
        }
        // dn is always returned as part of the base response.
        UserFieldType::Dn => return None,
        UserFieldType::EntryDn => {
            vec![format!("uid={},ou=people,{}", &user.user_id, base_dn_str).into_bytes()]
        }
        UserFieldType::MemberOf => groups
            .into_iter()
            .flatten()
            .map(|id_and_name| {
                format!("cn={},ou=groups,{}", &id_and_name.display_name, base_dn_str).into_bytes()
            })
            .collect(),
        UserFieldType::PrimaryField(UserColumn::UserId) => {
            vec![user.user_id.to_string().into_bytes()]
        }
        UserFieldType::PrimaryField(UserColumn::Email) => vec![user.email.to_string().into_bytes()],
        UserFieldType::PrimaryField(
            UserColumn::LowercaseEmail
            | UserColumn::PasswordHash
            | UserColumn::TotpSecret
            | UserColumn::MfaType,
        ) => panic!("Should not get here"),
        UserFieldType::PrimaryField(UserColumn::Uuid) => vec![user.uuid.to_string().into_bytes()],
        UserFieldType::PrimaryField(UserColumn::DisplayName) => {
            vec![user.display_name.clone()?.into_bytes()]
        }
        UserFieldType::PrimaryField(UserColumn::CreationDate) => vec![chrono::Utc
            .from_utc_datetime(&user.creation_date)
            .to_rfc3339()
            .into_bytes()],
        UserFieldType::Attribute(attr, _, _) => {
            get_custom_attribute::<SchemaUserAttributeExtractor>(&user.attributes, &attr, schema)?
        }
        UserFieldType::NoMatch => match attribute.as_str() {
            "1.1" => return None,
            // We ignore the operational attribute wildcard.
            "+" => return None,
            "*" => {
                panic!(
                    "Matched {}, * should have been expanded into attribute list and * removed",
                    attribute
                )
            }
            _ => {
                if ignored_user_attributes.contains(&attribute) {
                    return None;
                }
                get_custom_attribute::<SchemaUserAttributeExtractor>(
                    &user.attributes,
                    &attribute,
                    schema,
                )
                .or_else(|| {
                    warn!(
                        r#"Ignoring unrecognized group attribute: {}\n\
                      To disable this warning, add it to "ignored_user_attributes" in the config."#,
                        attribute
                    );
                    None
                })?
            }
        },
    };
    if attribute_values.len() == 1 && attribute_values[0].is_empty() {
        None
    } else {
        Some(attribute_values)
    }
}

const ALL_USER_ATTRIBUTE_KEYS: &[&str] = &[
    "objectclass",
    "uid",
    "mail",
    "givenname",
    "sn",
    "cn",
    "jpegPhoto",
    "createtimestamp",
    "entryuuid",
];

fn make_ldap_search_user_result_entry(
    user: User,
    base_dn_str: &str,
    expanded_attributes: &[&str],
    groups: Option<&[GroupDetails]>,
    ignored_user_attributes: &[AttributeName],
    schema: &PublicSchema,
) -> LdapSearchResultEntry {
    let dn = format!("uid={},ou=people,{}", user.user_id.as_str(), base_dn_str);
    LdapSearchResultEntry {
        dn,
        attributes: expanded_attributes
            .iter()
            .filter_map(|a| {
                let values = get_user_attribute(
                    &user,
                    a,
                    base_dn_str,
                    groups,
                    ignored_user_attributes,
                    schema,
                )?;
                Some(LdapPartialAttribute {
                    atype: a.to_string(),
                    vals: values,
                })
            })
            .collect::<Vec<LdapPartialAttribute>>(),
    }
}

fn get_user_attribute_equality_filter(
    field: &AttributeName,
    typ: AttributeType,
    is_list: bool,
    value: &str,
) -> LdapResult<UserRequestFilter> {
    deserialize_attribute_value(&[value.to_owned()], typ, is_list)
        .map_err(|e| LdapError {
            code: LdapResultCode::Other,
            message: format!("Invalid value for attribute {}: {}", field, e),
        })
        .map(|v| UserRequestFilter::AttributeEquality(field.clone(), v))
}

fn convert_user_filter(
    ldap_info: &LdapInfo,
    filter: &LdapFilter,
    schema: &PublicSchema,
) -> LdapResult<UserRequestFilter> {
    let rec = |f| convert_user_filter(ldap_info, f, schema);
    match filter {
        LdapFilter::And(filters) => Ok(UserRequestFilter::And(
            filters.iter().map(rec).collect::<LdapResult<_>>()?,
        )),
        LdapFilter::Or(filters) => Ok(UserRequestFilter::Or(
            filters.iter().map(rec).collect::<LdapResult<_>>()?,
        )),
        LdapFilter::Not(filter) => Ok(UserRequestFilter::Not(Box::new(rec(filter)?))),
        LdapFilter::Equality(field, value) => {
            let field = AttributeName::from(field.as_str());
            let value = value.to_ascii_lowercase();
            match map_user_field(&field, schema) {
                UserFieldType::PrimaryField(UserColumn::UserId) => {
                    Ok(UserRequestFilter::UserId(UserId::new(&value)))
                }
                UserFieldType::PrimaryField(field) => Ok(UserRequestFilter::Equality(field, value)),
                UserFieldType::Attribute(field, typ, is_list) => {
                    get_user_attribute_equality_filter(&field, typ, is_list, &value)
                }
                UserFieldType::NoMatch => {
                    if !ldap_info.ignored_user_attributes.contains(&field) {
                        warn!(
                            r#"Ignoring unknown user attribute "{}" in filter.\n\
                                      To disable this warning, add it to "ignored_user_attributes" in the config"#,
                            field
                        );
                    }
                    Ok(UserRequestFilter::from(false))
                }
                UserFieldType::ObjectClass => Ok(UserRequestFilter::from(
                    matches!(
                        value.as_str(),
                        "person" | "inetorgperson" | "posixaccount" | "mailaccount"
                    ) || schema
                        .get_schema()
                        .extra_user_object_classes
                        .contains(&LdapObjectClass::from(value)),
                )),
                UserFieldType::MemberOf => Ok(UserRequestFilter::MemberOf(
                    get_group_id_from_distinguished_name(
                        &value,
                        &ldap_info.base_dn,
                        &ldap_info.base_dn_str,
                    )?,
                )),
                UserFieldType::EntryDn | UserFieldType::Dn => {
                    Ok(get_user_id_from_distinguished_name(
                        value.as_str(),
                        &ldap_info.base_dn,
                        &ldap_info.base_dn_str,
                    )
                    .map(UserRequestFilter::UserId)
                    .unwrap_or_else(|_| {
                        warn!("Invalid dn filter on user: {}", value);
                        UserRequestFilter::from(false)
                    }))
                }
            }
        }
        LdapFilter::Present(field) => {
            let field = AttributeName::from(field.as_str());
            // Check that it's a field we support.
            Ok(UserRequestFilter::from(
                field.as_str() == "objectclass"
                    || field.as_str() == "dn"
                    || field.as_str() == "distinguishedname"
                    || !matches!(map_user_field(&field, schema), UserFieldType::NoMatch),
            ))
        }
        LdapFilter::Substring(field, substring_filter) => {
            let field = AttributeName::from(field.as_str());
            match map_user_field(&field, schema) {
                UserFieldType::PrimaryField(UserColumn::UserId) => Ok(
                    UserRequestFilter::UserIdSubString(substring_filter.clone().into()),
                ),
                UserFieldType::Attribute(_, _, _)
                | UserFieldType::ObjectClass
                | UserFieldType::MemberOf
                | UserFieldType::Dn
                | UserFieldType::EntryDn
                | UserFieldType::PrimaryField(UserColumn::CreationDate)
                | UserFieldType::PrimaryField(UserColumn::Uuid) => Err(LdapError {
                    code: LdapResultCode::UnwillingToPerform,
                    message: format!(
                        "Unsupported user attribute for substring filter: {:?}",
                        field
                    ),
                }),
                UserFieldType::NoMatch => Ok(UserRequestFilter::from(false)),
                UserFieldType::PrimaryField(field) => Ok(UserRequestFilter::SubString(
                    field,
                    substring_filter.clone().into(),
                )),
            }
        }
        _ => Err(LdapError {
            code: LdapResultCode::UnwillingToPerform,
            message: format!("Unsupported user filter: {:?}", filter),
        }),
    }
}

fn expand_user_attribute_wildcards(attributes: &[String]) -> Vec<&str> {
    expand_attribute_wildcards(attributes, ALL_USER_ATTRIBUTE_KEYS)
}

#[instrument(skip_all, level = "debug", fields(ldap_filter, request_groups))]
pub async fn get_user_list<Backend: UserListerBackendHandler>(
    ldap_info: &LdapInfo,
    ldap_filter: &LdapFilter,
    request_groups: bool,
    base: &str,
    backend: &Backend,
    schema: &PublicSchema,
) -> LdapResult<Vec<UserAndGroups>> {
    let filters = convert_user_filter(ldap_info, ldap_filter, schema)?;
    debug!(?filters);
    backend
        .list_users(Some(filters), request_groups)
        .await
        .map_err(|e| LdapError {
            code: LdapResultCode::Other,
            message: format!(r#"Error while searching user "{}": {:#}"#, base, e),
        })
}

pub fn convert_users_to_ldap_op<'a>(
    users: Vec<UserAndGroups>,
    attributes: &'a [String],
    ldap_info: &'a LdapInfo,
    schema: &'a PublicSchema,
) -> impl Iterator<Item = LdapOp> + 'a {
    let expanded_attributes = if users.is_empty() {
        None
    } else {
        Some(expand_user_attribute_wildcards(attributes))
    };
    users.into_iter().map(move |u| {
        LdapOp::SearchResultEntry(make_ldap_search_user_result_entry(
            u.user,
            &ldap_info.base_dn_str,
            expanded_attributes.as_ref().unwrap(),
            u.groups.as_deref(),
            &ldap_info.ignored_user_attributes,
            schema,
        ))
    })
}