use crate::{LogLevel, info, verb};
use regex::Regex;
use serde_json::{Map, Value, json};
use std::path::{Path, PathBuf};
use std::{env, fmt, fs};
use walkdir::WalkDir;
use yaml_serde;

#[derive(Debug)]
pub struct Specification {
    pub partitional: PathBuf,
    pub regional: PathBuf,
    pub common: PathBuf,
    pub zonal: PathBuf,
    pub device: PathBuf,
    pub compiled: Value,
}

impl Specification {
    pub fn build(
        partitional: PathBuf,
        regional: PathBuf,
        common: PathBuf,
        zonal: PathBuf,
        device: PathBuf,
    ) -> Result<Self, Box<dyn std::error::Error>> {
        let json_values: Vec<Value> = [&partitional, &regional, &common, &zonal, &device]
            .iter()
            .filter_map(|path| fs::read_to_string(path).ok())
            .map(|content| yaml_serde::from_str::<Value>(&content))
            .collect::<Result<Vec<Value>, _>>()?;

        let merged_map: Map<String, Value> = json_values
            .into_iter()
            .filter_map(|v| v.as_object().cloned())
            .flat_map(|obj| obj.into_values().filter_map(|v| v.as_object().cloned()))
            .flatten()
            .collect();

        let compiled = json!({"data": merged_map});

        Ok(Self {
            partitional,
            regional,
            common,
            zonal,
            device,
            compiled,
        })
    }

    pub fn get_layer(&self) -> String {
        self.device
            .parent()
            .unwrap()
            .file_name()
            .unwrap()
            .to_string_lossy()
            .chars()
            .filter(|c| !c.is_numeric())
            .collect::<String>()
    }
}

impl fmt::Display for Specification {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(
            f,
            "Specification:\nPartitional: {}\nRegional: {}\nCommon: {}\nZonal: {}\nDevice: {}\nCompiled:\n{}",
            self.partitional.display(),
            self.regional.display(),
            self.common.display(),
            self.zonal.display(),
            self.device.display(),
            self.compiled
        )
    }
}

pub fn compile(pattern: &Regex, spec_path: &String, dbg: LogLevel) -> Vec<Specification> {
    let spec_list: Vec<PathBuf> = filter_specs(pattern, get_specs(spec_path, dbg));
    info!(
        dbg,
        "Matched {} devices against '{}'",
        &spec_list.len(),
        &pattern
    );
    for spec in &spec_list {
        verb!(dbg, " | {}", spec.display());
    }
    let mut specifications: Vec<Specification> = Vec::new();
    for spec in spec_list {
        let zonal = get_zonal(&spec);
        let common = get_common(&spec);
        let regional = get_regional(&spec);
        let partitional = get_partitional(&common, &regional);
        specifications.push(
            match Specification::build(partitional, regional, common, zonal, spec) {
                Ok(compiled_spec) => compiled_spec,
                Err(e) => panic!("failed to build Specification: {}", e),
            },
        )
    }
    specifications
}

fn get_partitional(common: &PathBuf, regional: &PathBuf) -> PathBuf {
    let re = Regex::new(r"partition: ([^\n\r$]+)").expect("failed");

    [common, regional]
        .iter()
        .find_map(|path| {
            fs::read_to_string(path).ok().and_then(|contents| {
                re.captures(&contents).and_then(|captures| {
                    captures.get(1).map(|matched| {
                        PathBuf::from(format!("./spec/common/{}.yaml", matched.as_str().trim()))
                    })
                })
            })
        })
        .unwrap_or_else(|| PathBuf::from("./spec/common/default.yaml"))
}

fn get_regional(path: &PathBuf) -> PathBuf {
    let dir_name = path
        .parent()
        .unwrap()
        .file_name()
        .unwrap()
        .to_string_lossy()
        .into_owned();

    path.parent()
        .unwrap()
        .parent()
        .unwrap()
        .join("common")
        .join(format!("{}.yaml", &dir_name[0..2]))
}

fn get_common(spec: &PathBuf) -> PathBuf {
    spec.with_file_name("common.yaml")
}

fn get_zonal(spec: &PathBuf) -> PathBuf {
    let zone = spec
        .file_name()
        .and_then(|f| f.to_str())
        .and_then(|f| f.split_once('-'))
        .map(|(zone, _)| spec.with_file_name(zone))
        .unwrap_or_else(|| spec.with_file_name("common.yaml"));

    PathBuf::from(format!("{}.common.yaml", zone.to_str().unwrap()))
}

fn filter_specs(pattern: &Regex, spec_list: Vec<PathBuf>) -> Vec<PathBuf> {
    spec_list
        .into_iter()
        .filter(|spec| {
            spec.file_name()
                .and_then(|name| name.to_str())
                .map_or(false, |name| pattern.is_match(name))
        })
        .collect()
}

fn get_specs(spec_path: &String, dbg: LogLevel) -> Vec<PathBuf> {
    let mut result = Vec::new();
    let root = Path::new(&spec_path);
    for entry in WalkDir::new(root).into_iter().filter_map(|e| e.ok()) {
        if let Ok(path) = entry.path().strip_prefix(root) {
            let path_str = path.to_string_lossy().to_string();
            if !path_str.contains("common") && path_str.ends_with("yaml") {
                result.push(root.join(path));
            }
        }
    }
    info!(
        dbg,
        "Skyforge found {} renderable devices in {}",
        result.len(),
        env::current_dir().unwrap().display()
    );
    result
}