//! Import from a simple csv format logic.
#[cfg(test)]
#[path = "../../../tests/unit/extensions/import/csv_test.rs"]
mod csv_test;

pub use self::actual::read_csv_problem;

#[cfg(feature = "csv-format")]
mod actual {
    extern crate csv;
    extern crate serde;

    use serde::Deserialize;
    use std::collections::{HashMap, HashSet};
    use std::error::Error;
    use std::io::{BufReader, Read};
    use vrp_pragmatic::format::problem::*;
    use vrp_pragmatic::format::{FormatError, Location};

    #[derive(Debug, Deserialize)]
    #[serde(rename_all = "UPPERCASE")]
    struct CsvJob {
        id: String,
        lat: f64,
        lng: f64,
        demand: i32,
        duration: usize,
        tw_start: Option<String>,
        tw_end: Option<String>,
    }

    #[derive(Debug, Deserialize)]
    #[serde(rename_all = "UPPERCASE")]
    struct CsvVehicle {
        id: String,
        lat: f64,
        lng: f64,
        capacity: i32,
        tw_start: String,
        tw_end: String,
        amount: usize,
        profile: String,
    }

    fn read_csv_entries<T, R: Read>(reader: BufReader<R>) -> Result<Vec<T>, Box<dyn Error>>
    where
        for<'de> T: Deserialize<'de>,
    {
        let mut reader = csv::Reader::from_reader(reader);
        let mut entries = vec![];

        for entry in reader.deserialize() {
            entries.push(entry?);
        }

        Ok(entries)
    }

    fn parse_tw(start: Option<String>, end: Option<String>) -> Option<Vec<String>> {
        match (start, end) {
            (Some(start), Some(end)) => Some(vec![start, end]),
            _ => None,
        }
    }

    fn read_jobs<R: Read>(reader: BufReader<R>) -> Result<Vec<Job>, Box<dyn Error>> {
        let get_task = |job: &CsvJob| JobTask {
            places: vec![JobPlace {
                location: Location::Coordinate { lat: job.lat, lng: job.lng },
                duration: job.duration as f64,
                times: parse_tw(job.tw_start.clone(), job.tw_end.clone()).map(|tw| vec![tw]),
                tag: None,
            }],
            demand: if job.demand != 0 { Some(vec![job.demand.abs()]) } else { None },
            order: None,
        };

        let get_tasks = |jobs: &Vec<&CsvJob>, filter: Box<dyn Fn(&CsvJob) -> bool>| {
            let tasks = jobs.iter().filter(|j| (filter)(j)).map(|job| get_task(job)).collect::<Vec<_>>();
            if tasks.is_empty() {
                None
            } else {
                Some(tasks)
            }
        };

        let jobs = read_csv_entries::<CsvJob, _>(reader)?
            .iter()
            .fold(HashMap::new(), |mut acc, job| {
                acc.entry(&job.id).or_insert_with(Vec::new).push(job);
                acc
            })
            .into_iter()
            .map(|(job_id, tasks)| Job {
                id: job_id.clone(),
                pickups: get_tasks(&tasks, Box::new(|j| j.demand > 0)),
                deliveries: get_tasks(&tasks, Box::new(|j| j.demand < 0)),
                replacements: None,
                services: get_tasks(&tasks, Box::new(|j| j.demand == 0)),
                skills: None,
                value: None,
                group: None,
                compatibility: None,
            })
            .collect();

        Ok(jobs)
    }

    fn read_vehicles<R: Read>(reader: BufReader<R>) -> Result<Vec<VehicleType>, Box<dyn Error>> {
        let vehicles = read_csv_entries::<CsvVehicle, _>(reader)?
            .into_iter()
            .map(|vehicle| {
                let depot_location = Location::Coordinate { lat: vehicle.lat, lng: vehicle.lng };

                VehicleType {
                    type_id: vehicle.id.clone(),
                    vehicle_ids: (1..=vehicle.amount).map(|seq| format!("{}_{}", vehicle.profile, seq)).collect(),
                    profile: VehicleProfile { matrix: vehicle.profile, scale: None },
                    costs: VehicleCosts { fixed: Some(25.), distance: 0.0002, time: 0.005 },
                    shifts: vec![VehicleShift {
                        start: ShiftStart {
                            earliest: vehicle.tw_start,
                            latest: None,
                            location: depot_location.clone(),
                        },
                        end: Some(ShiftEnd { earliest: None, latest: vehicle.tw_end, location: depot_location }),
                        dispatch: None,
                        breaks: None,
                        reloads: None,
                    }],
                    capacity: vec![vehicle.capacity],
                    skills: None,
                    limits: None,
                }
            })
            .collect();

        Ok(vehicles)
    }

    fn create_format_error(entity: &str, error: Box<dyn Error>) -> FormatError {
        FormatError::new_with_details(
            "E0000".to_string(),
            format!("cannot read {entity}"),
            format!("check {entity} definition"),
            format!("{error}",),
        )
    }

    /// Reads problem from csv format.
    pub fn read_csv_problem<R1: Read, R2: Read>(
        jobs_reader: BufReader<R1>,
        vehicles_reader: BufReader<R2>,
    ) -> Result<Problem, FormatError> {
        let jobs = read_jobs(jobs_reader).map_err(|err| create_format_error("jobs", err))?;
        let vehicles = read_vehicles(vehicles_reader).map_err(|err| create_format_error("vehicles", err))?;
        let matrix_profile_names = vehicles.iter().map(|v| v.profile.matrix.clone()).collect::<HashSet<_>>();

        Ok(Problem {
            plan: Plan { jobs, relations: None, clustering: None },
            fleet: Fleet {
                vehicles,
                profiles: matrix_profile_names.into_iter().map(|name| MatrixProfile { name, speed: None }).collect(),
                resources: None,
            },
            objectives: None,
        })
    }
}

#[cfg(not(feature = "csv-format"))]
mod actual {
    use std::io::{BufReader, Read};
    use vrp_pragmatic::format::problem::Problem;
    use vrp_pragmatic::format::FormatError;

    /// A stub method for reading problem from csv format.
    pub fn read_csv_problem<R1: Read, R2: Read>(
        _jobs_reader: BufReader<R1>,
        _vehicles_reader: BufReader<R2>,
    ) -> Result<Problem, FormatError> {
        unreachable!("csv-format feature is not included")
    }
}