use chrono::{Datelike, Days, Months, NaiveDate};
use common::ron_api;
use gloo::storage::{LocalStorage, Storage};
use ron::ser::{PrettyConfig, to_string_pretty};
use serde::{Deserialize, Serialize};
use thiserror::Error;

use crate::{calendar, request};

#[derive(Error, Debug)]
pub enum Error {
    #[error("Request error: {0}")]
    Request(#[from] request::Error),
}

type Result<T> = std::result::Result<T, Error>;

#[derive(Clone, Copy)]
pub struct RecipeScheduler {
    is_local: bool,
}

pub enum ScheduleRecipeResult {
    Ok,
    RecipeAlreadyScheduledAtThisDate,
}

impl From<ron_api::ScheduleRecipeResult> for ScheduleRecipeResult {
    fn from(api_res: ron_api::ScheduleRecipeResult) -> Self {
        match api_res {
            ron_api::ScheduleRecipeResult::Ok => Self::Ok,
            ron_api::ScheduleRecipeResult::RecipeAlreadyScheduledAtThisDate => {
                Self::RecipeAlreadyScheduledAtThisDate
            }
        }
    }
}

#[derive(Serialize, Deserialize, Clone, Debug)]
struct ScheduledRecipesStore {
    recipe_id: i64,
    date: NaiveDate,
}

fn build_key(year: i32, month: u32) -> String {
    format!("scheduled_recipes-{}-{}", year, month)
}

fn load_scheduled_recipes(year: i32, month: u32) -> Vec<ScheduledRecipesStore> {
    LocalStorage::get::<Vec<ScheduledRecipesStore>>(build_key(year, month)).unwrap_or_default()
}

fn save_scheduled_recipes(scheduled_recipes: Vec<ScheduledRecipesStore>, year: i32, month: u32) {
    LocalStorage::set(build_key(year, month), scheduled_recipes).unwrap();
}

impl RecipeScheduler {
    pub fn new(is_local: bool) -> Self {
        Self { is_local }
    }

    pub async fn get_scheduled_recipes(
        &self,
        start_date: NaiveDate,
        end_date: NaiveDate,
    ) -> Result<Vec<(NaiveDate, String, i64)>> {
        if self.is_local {
            let mut recipe_ids_and_dates = vec![];
            let mut current_date = start_date;
            while current_date <= end_date {
                current_date = current_date + Months::new(1);
                for recipe in load_scheduled_recipes(current_date.year(), current_date.month0()) {
                    if recipe.date >= start_date && recipe.date <= end_date {
                        recipe_ids_and_dates.push(recipe);
                    }
                }
            }

            if recipe_ids_and_dates.is_empty() {
                return Ok(vec![]);
            }

            let titles: ron_api::Strings = request::get(
                "recipe/titles",
                ron_api::Ids {
                    ids: recipe_ids_and_dates
                        .iter()
                        .map(|r| r.recipe_id)
                        .collect::<Vec<_>>(),
                },
            )
            .await?;

            Ok(recipe_ids_and_dates
                .iter()
                .zip(titles.strs.into_iter())
                .map(|(id_and_date, title)| (id_and_date.date, title, id_and_date.recipe_id))
                .collect::<Vec<_>>())
        } else {
            let scheduled_recipes: ron_api::ScheduledRecipes = request::get(
                "calendar/scheduled_recipes",
                ron_api::DateRange {
                    start_date,
                    end_date,
                },
            )
            .await?;

            Ok(scheduled_recipes.recipes)
        }
    }

    pub async fn shedule_recipe(
        &self,
        recipe_id: i64,
        date: NaiveDate,
        servings: u32,
        add_ingredients_to_shopping_list: bool,
    ) -> Result<ScheduleRecipeResult> {
        if self.is_local {
            // TODO: use 'add_ingredients_to_shopping_list'.
            let mut recipe_ids_and_dates = load_scheduled_recipes(date.year(), date.month0());
            for recipe in recipe_ids_and_dates.iter() {
                if recipe.recipe_id == recipe_id && recipe.date == date {
                    return Ok(ScheduleRecipeResult::RecipeAlreadyScheduledAtThisDate);
                }
            }
            recipe_ids_and_dates.push(ScheduledRecipesStore { recipe_id, date });
            save_scheduled_recipes(recipe_ids_and_dates, date.year(), date.month0());
            Ok(ScheduleRecipeResult::Ok)
        } else {
            request::post::<ron_api::ScheduleRecipeResult, _>(
                "calendar/schedule_recipe",
                ron_api::ScheduleRecipe {
                    recipe_id,
                    date,
                    servings,
                    add_ingredients_to_shopping_list,
                },
            )
            .await
            .map_err(Error::from)
            .map(From::<ron_api::ScheduleRecipeResult>::from)
        }
    }

    // pub async fn remove_scheduled_recipe(
    //     &self,
    //     recipe_id: i64
    // )
}