use std::{borrow::Cow, collections::HashMap};

use log::{info, warn};

use crate::{
    arn::ARN,
    auth::UserIdentity,
    cache::CacheInner,
    policy::{utils::get_values_from_claims, Args, Policy},
    store::Store,
    Error,
};

pub(crate) struct Handler<'m, T> {
    cache: CacheInner,
    api: &'m T,
    roles: &'m HashMap<ARN, Vec<String>>,
}

impl<'m, T> Handler<'m, T> {
    pub fn new(cache: CacheInner, api: &'m T, roles: &'m HashMap<ARN, Vec<String>>) -> Self {
        Self { cache, api, roles }
    }
}

impl<'m, T> Handler<'m, T>
where
    T: Store,
{
    #[inline]
    fn get_user<'a>(&self, user_name: &'a str) -> Option<&UserIdentity> {
        self.cache
            .users
            .get(user_name)
            .or_else(|| self.cache.sts_accounts.get(user_name))
    }

    async fn get_policy(&self, name: &str, _groups: &[String]) -> crate::Result<Vec<String>> {
        if name.is_empty() {
            return Err(Error::InvalidArgument);
        }

        todo!()
        // self.api.policy_db_get(name, groups)
    }

    /// 如果是临时用户，返回Ok(Some(partent_name)))
    /// 如果不是临时用户，返回Ok(None)
    fn is_temp_user<'a>(&self, user_name: &'a str) -> crate::Result<Option<&str>> {
        let user = self
            .get_user(user_name)
            .ok_or_else(|| Error::NoSuchUser(user_name.to_owned()))?;

        if user.credentials.is_temp() {
            Ok(Some(&user.credentials.parent_user))
        } else {
            Ok(None)
        }
    }

    /// 如果是临时用户，返回Ok(Some(partent_name)))
    /// 如果不是临时用户，返回Ok(None)
    fn is_service_account<'a>(&self, user_name: &'a str) -> crate::Result<Option<&str>> {
        let user = self
            .get_user(user_name)
            .ok_or_else(|| Error::NoSuchUser(user_name.to_owned()))?;

        if user.credentials.is_service_account() {
            Ok(Some(&user.credentials.parent_user))
        } else {
            Ok(None)
        }
    }

    // todo
    pub fn is_allowed_sts(&self, args: &Args, parent: &str) -> bool {
        warn!("unimplement is_allowed_sts");
        false
    }

    // todo
    pub async fn is_allowed_service_account<'a>(&self, args: &Args<'a>, parent: &str) -> bool {
        let Some(p) = args.claims.get(parent) else {
            return false;
        };

        if let Some(parent_in_chaim) = p.as_str() {
            if parent_in_chaim != parent {
                return false;
            }
        } else {
            return false;
        }

        let is_owner_derived = parent == "rustfsadmin"; // todo ,使用全局变量
        let role_arn = args.get_role_arn();
        let mut svc_policies = None;

        if is_owner_derived {
        } else if let Some(x) = role_arn {
            let Ok(arn) = x.parse::<ARN>() else {
                info!("error parsing role ARN {x}");
                return false;
            };

            svc_policies = self.roles.get(&arn).map(|x| Cow::from(x));
        } else {
            let Ok(mut p) = self.get_policy(parent, &args.groups[..]).await else { return false };
            if p.is_empty() {
                // todo iamPolicyClaimNameOpenID
                let (p1, _) = get_values_from_claims(&args.claims, "");
                p = p1;
            }
            svc_policies = Some(Cow::Owned(p));
        }

        if is_owner_derived && svc_policies.as_ref().map(|x| x.as_ref().len()).unwrap_or_default() == 0 {
            return false;
        }

        false
    }

    pub async fn get_combined_policy(&self, _policies: &[String]) -> Policy {
        todo!()
    }

    pub async fn is_allowed<'a>(&self, args: Args<'a>) -> bool {
        if args.is_owner {
            return true;
        }

        match self.is_temp_user(&args.account) {
            Ok(Some(parent)) => return self.is_allowed_sts(&args, parent),
            Err(_) => return false,
            _ => {}
        }

        match self.is_service_account(&args.account) {
            Ok(Some(parent)) => return self.is_allowed_service_account(&args, parent).await,
            Err(_) => return false,
            _ => {}
        }

        let Ok(policies) = self.get_policy(&args.account, &args.groups).await else { return false };

        if policies.is_empty() {
            return false;
        }

        let policy = self.get_combined_policy(&policies[..]).await;
        policy.is_allowed(&args)
    }
}