use std::fs;
use std::io::{BufWriter, Write};

use serde::Deserialize;

fn main() {
    println!("cargo:rerun-if-changed=build.rs");
    if let Err(e) = gen_data_mod() {
        eprintln!("Error: {}", e);
    }
}

fn gen_data_mod() -> Result<(), std::io::Error> {
    let file = fs::File::create("src/data.rs")?;
    let mut buf = BufWriter::new(file);
    write_structs(&mut buf)?;
    println!("cargo:rerun-if-changed=data/ingredients/*.toml");
    write_ingredients(&mut buf)?;
    Ok(())
}

fn write_structs(file: &mut BufWriter<fs::File>) -> Result<(), std::io::Error> {
    let structs = r#"
#[derive(Debug)]
pub struct Ingredient {
    pub key: &'static str,
    pub translates: IngredientTranslate,
}

#[derive(Debug)]
pub struct IngredientTranslate {
    pub ru: &'static str,
    pub en: Option<&'static str>,
}

#[derive(Debug)]
pub struct Recipe {
    key: &'static str,
    ingredients: Vec<RecipeIngredient>,
    steps: u8,
    translates: RecipeTranslates,
}

#[derive(Debug)]
pub struct RecipeIngredient {
    key: &'static str,
    measure: RecipeIngredientMeasure,
}

#[derive(Debug)]
pub enum RecipeIngredientMeasure {
    Gram(u32),
    KiloGram(u32),
    MilliLiter(u32),
    Liter(u32),
}

#[derive(Debug)]
pub struct RecipeTranslates {
    ru: RecipeTranslate,
    en: Option<RecipeTranslate>,
}

#[derive(Debug)]
pub struct RecipeTranslate {
    name: &'static str,
    instructions: Vec<&'static str>,
}
"#;

    writeln!(file, "{}", structs)?;

    Ok(())
}

#[derive(Deserialize, Debug)]
pub struct Main {
    ingredients: Option<Vec<Ingredient>>,
    recipes: Option<Vec<Recipe>>,
}

#[derive(Deserialize, Debug)]
pub struct Ingredient {
    key: String,
    translates: IngredientTranslate,
}

#[derive(Deserialize, Debug)]
pub struct IngredientTranslate {
    ru: String,
    en: Option<String>,
}

#[derive(Deserialize, Debug)]
pub struct Recipe {
    key: String,
    ingredients: Vec<RecipeIngredient>,
    steps: u8,
    translates: RecipeTranslates,
}

#[derive(Deserialize, Debug)]
pub struct RecipeIngredient {
    key: String,
    #[serde(flatten)]
    measure: RecipeIngredientMeasure,
}

#[derive(Deserialize, Debug)]
pub enum RecipeIngredientMeasure {
    #[serde(rename = "g")]
    Gram(u32),
    #[serde(rename = "kg")]
    KiloGram(u32),
    #[serde(rename = "ml")]
    MilliLiter(u32),
    #[serde(rename = "l")]
    Liter(u32),
}

#[derive(Deserialize, Debug)]
pub struct RecipeTranslates {
    ru: RecipeTranslate,
    en: Option<RecipeTranslate>,
}

#[derive(Deserialize, Debug)]
pub struct RecipeTranslate {
    name: String,
    instructions: Vec<String>,
}

fn write_ingredients(file: &mut BufWriter<fs::File>) -> Result<(), std::io::Error> {
    let ingredients = get_ingredient_configs()?;

    writeln!(
        file,
        "pub const INGREDIENTS: [Ingredient; {}] = [{}];",
        ingredients.len(),
        ingredients
            .into_iter()
            .map(|i| to_ingredient_data_content(1, i))
            .collect::<String>()
    )?;

    Ok(())
}

fn to_ingredient_data_content(indent_size: usize, ingredient: Ingredient) -> String {
    format!(
        r#"
{i}Ingredient {{
{i}    key: {key:?},
{i}    translates: IngredientTranslate {{
{i}        ru: {tr_ru:?},
{i}        en: {tr_en:?},
{i}    }},
{i}}},
"#,
        i = indent(indent_size),
        key = to_str(ingredient.key),
        tr_ru = to_str(ingredient.translates.ru),
        tr_en = ingredient.translates.en.map(to_str),
    )
}

fn get_ingredient_configs() -> Result<Vec<Ingredient>, std::io::Error> {
    Ok(fs::read_dir("data/ingredients")?
        .map(|res| res.and_then(|e| fs::read_to_string(e.path())))
        .collect::<Result<Vec<_>, std::io::Error>>()?
        .into_iter()
        .map(|content| toml::from_str(&content).unwrap())
        .filter_map(|cfg: Main| cfg.ingredients)
        .flatten()
        .collect::<Vec<Ingredient>>())
}

fn indent(indent_size: usize) -> String {
    std::iter::repeat(" ").take(indent_size * 4).collect()
}

fn to_str(string: String) -> &'static str {
    Box::leak(string.into_boxed_str())
}