use std::fmt;
use std::marker::PhantomData;
use std::collections::BTreeMap;
use serde::de::{self, Visitor};
use serde::{Deserialize, Deserializer};

#[derive(Deserialize, Debug)]
pub struct GalleryTitleInfo {
    pub english: Option<String>,
    pub japanese: Option<String>,
    pub pretty: Option<String>,
}

#[derive(Deserialize, Debug)]
pub struct GalleryImageInfo {
    pub t: String,
    pub w: i32,
    pub h: i32
}

#[derive(Deserialize, Debug)]
pub struct GalleryImagesInfo {
    pub pages: Vec<GalleryImageInfo>,
    pub cover: GalleryImageInfo,
    pub thumbnail: GalleryImageInfo
}

#[derive(Deserialize, Debug)]
pub struct GalleryTagInfo {
    pub id: i32,
    pub r#type: String,
    pub name: String,
    pub url: String,
    pub count: i32
}

#[derive(Deserialize, Debug)]
pub struct GalleryInfoSuccess {
    #[serde(deserialize_with = "convert_to_i32")]
    pub id: i32,
    pub media_id: String,
    pub title: GalleryTitleInfo,
    pub images: GalleryImagesInfo,
    pub scanlator: String,
    pub upload_date: i32,
    pub tags: Vec<GalleryTagInfo>,
    pub num_pages: i32,
    pub num_favorites: i32
}

#[derive(Deserialize, Debug)]
pub struct GalleryInfoError {
    pub error: String
}

#[derive(Deserialize, Debug)]
#[serde(untagged)]
pub enum GalleryInfo {
    Info(GalleryInfoSuccess),
    Error(GalleryInfoError)
}

#[derive(Deserialize, Debug)]
pub struct SearchInfo {
    pub result: Vec<GalleryInfoSuccess>,
    pub num_pages: i32,
    pub per_page: i32
}

impl fmt::Display for GalleryInfoSuccess {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut text = format!("Sauce: {}\nTitle: ", self.id);
        let japanese_title = self.title.japanese.as_ref();
        let english_title = self.title.english.as_ref();
        if english_title.filter(|i| !i.is_empty()).is_some() {
            text.push_str(english_title.unwrap());
            if japanese_title.filter(|i| !i.is_empty()).is_some() {
                text.push_str(&format!("\nJapanese Title: {}", japanese_title.unwrap()));
            }
        } else {
            text.push_str(japanese_title.unwrap());
        }
        let mut tag_hashmap = BTreeMap::new();
        for tag_info in &self.tags {
            let tag_key = tag_info.r#type.as_str();
            let tag_value = tag_info.name.as_str();
            let tag_vec = tag_hashmap.entry(tag_key).or_insert(Vec::new());
            tag_vec.push(tag_value);
        }
        for (tag_key, tag_value) in tag_hashmap {
            let tag_key = match tag_key {
                "tag" => "Tags",
                "artist" => "Artists",
                "parody" => "Parodies",
                "character" => "Characters",
                "group" => "Groups",
                "language" => "Languages",
                "category" => "Categories",
                _ => tag_key
            };
            text.push_str(&format!("\n{}: {}", tag_key, tag_value.join(", ")));
        }
        text.push_str(&format!("\nPages: {}\nFavorites: {}", self.num_pages, self.num_favorites));
        formatter.write_str(&text)
    }
}

fn convert_to_i32<'de, D>(deserializer: D) -> Result<i32, D::Error>
where
    D: Deserializer<'de>
{
    struct ConvertToI32<T>(PhantomData<fn() -> T>);

    impl<'de> Visitor<'de> for ConvertToI32<i32>
    {
        type Value = i32;

        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
            formatter.write_str("an integer between -2^31 and 2^31")
        }

        fn visit_i8<E>(self, value: i8) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            Ok(i32::from(value))
        }

        fn visit_i16<E>(self, value: i16) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            Ok(i32::from(value))
        }

        fn visit_i32<E>(self, value: i32) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            Ok(value)
        }

        fn visit_i64<E>(self, value: i64) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            use std::i32;
            if value >= i64::from(i32::MIN) && value <= i64::from(i32::MAX) {
                Ok(value as i32)
            } else {
                Err(E::custom(format!("i32 out of range: {}", value)))
            }
        }

        fn visit_u8<E>(self, value: u8) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            Ok(i32::from(value))
        }

        fn visit_u16<E>(self, value: u16) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            Ok(i32::from(value))
        }

        fn visit_u32<E>(self, value: u32) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            use std::{i32, u32};
            if value <= i32::MAX as u32 {
                Ok(value as i32)
            } else {
                Err(E::custom(format!("i32 out of range: {}", value)))
            }
        }

        fn visit_u64<E>(self, value: u64) -> Result<Self::Value, E>
        where
            E: de::Error
        {
            use std::{i32, u64};
            if value <= i32::MAX as u64 {
                Ok(value as i32)
            } else {
                Err(E::custom(format!("i32 out of range: {}", value)))
            }
        }

        fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
        where
            E: de::Error
        {
//            https://brokenco.de/2020/08/03/serde-deserialize-with-string.html
            value.parse::<i32>().map_err(serde::de::Error::custom)
        }
    }

    deserializer.deserialize_any(ConvertToI32(PhantomData))
}