// Copyright (c) 2021 ESR Labs GmbH. All rights reserved.
//
// NOTICE:  All information contained herein is, and remains
// the property of E.S.R.Labs and its suppliers, if any.
// The intellectual and technical concepts contained herein are
// proprietary to E.S.R.Labs and its suppliers and may be covered
// by German and Foreign Patents, patents in process, and are protected
// by trade secret or copyright law.
// Dissemination of this information or reproduction of this material
// is strictly forbidden unless prior written permission is obtained
// from E.S.R.Labs.

//! # filter definitions for filtering dlt messages
use crate::dlt;
use serde::{Deserialize, Serialize};
use std::{collections::HashSet, fs, io::Read, iter::FromIterator};

/// Describes what DLT message to filter out based on log-level and app/ecu/context-id
///
/// In the current form each filter element is independent from another, i.e. it is
/// not possible to define filters like:
/// - `app-id == "abc" && log-level <= WARN OR app-id == "foo" && log-level <= DEBUG`
///
/// only this is possible:
/// - `app-id is_one_of ["abc","foo"] AND log-level <= DEBUG`
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct DltFilterConfig {
    /// only select log entries with level MIN_LEVEL and more severe
    ///
    /// ``` text
    ///  1 => FATAL
    ///  2 => ERROR
    ///  3 => WARN
    ///  4 => INFO
    ///  5 => DEBUG
    ///  6 => VERBOSE
    /// ```
    pub min_log_level: Option<u8>,
    /// what app ids should be allowed.
    pub app_ids: Option<Vec<String>>,
    /// what ecu ids should be allowed
    pub ecu_ids: Option<Vec<String>>,
    /// what context ids should be allowed
    pub context_ids: Option<Vec<String>>,
    /// how many app ids exist in total
    pub app_id_count: i64,
    /// how many context ids exist in total
    pub context_id_count: i64,
}

/// A processed version of the filter configuration that can be used to parse dlt.
///
/// When a `DltFilterConfig` is received (e.g. as serialized json), this can easily
/// be converted into this processed version using `filter_config.into()`
#[derive(Clone, Debug)]
pub struct ProcessedDltFilterConfig {
    pub min_log_level: Option<dlt::LogLevel>,
    pub app_ids: Option<HashSet<String>>,
    pub ecu_ids: Option<HashSet<String>>,
    pub context_ids: Option<HashSet<String>>,
    pub app_id_count: i64,
    pub context_id_count: i64,
}

impl From<DltFilterConfig> for ProcessedDltFilterConfig {
    fn from(cfg: DltFilterConfig) -> Self {
        ProcessedDltFilterConfig {
            min_log_level: cfg.min_log_level.and_then(dlt::u8_to_log_level),
            app_ids: cfg.app_ids.map(HashSet::from_iter),
            ecu_ids: cfg.ecu_ids.map(HashSet::from_iter),
            context_ids: cfg.context_ids.map(HashSet::from_iter),
            app_id_count: cfg.app_id_count,
            context_id_count: cfg.context_id_count,
        }
    }
}

impl From<&DltFilterConfig> for ProcessedDltFilterConfig {
    fn from(cfg: &DltFilterConfig) -> Self {
        ProcessedDltFilterConfig {
            min_log_level: cfg.min_log_level.and_then(dlt::u8_to_log_level),
            app_ids: cfg.app_ids.as_ref().map(|s| HashSet::from_iter(s.clone())),
            ecu_ids: cfg.ecu_ids.as_ref().map(|s| HashSet::from_iter(s.clone())),
            context_ids: cfg
                .context_ids
                .as_ref()
                .map(|s| HashSet::from_iter(s.clone())),
            app_id_count: cfg.app_id_count,
            context_id_count: cfg.context_id_count,
        }
    }
}

/// Read filter config from a json file
pub fn read_filter_options(f: &mut fs::File) -> Option<DltFilterConfig> {
    let mut contents = String::new();
    f.read_to_string(&mut contents)
        .ok()
        .and_then(|_| serde_json::from_str(&contents[..]).ok())
}