use std::collections::HashMap;
use std::fmt;

use serde::de::{Deserializer, IgnoredAny, MapAccess, SeqAccess, Visitor};
use serde::Deserialize;
use url::Url;

use super::files::File;
use super::id::{CommentId, EventId, FileId, GameId, MemberId, ModId, ResourceId, UserId};
use super::{deserialize_empty_object, DeserializeField, MissingField, TargetPlatform};
use super::{Logo, Status, User};

/// See the [Mod Object](https://docs.mod.io/#mod-object) docs for more information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Mod {
    pub id: ModId,
    pub game_id: GameId,
    pub status: Status,
    pub visible: Visibility,
    pub submitted_by: User,
    pub date_added: u64,
    pub date_updated: u64,
    pub date_live: u64,
    pub maturity_option: MaturityOption,
    pub community_options: CommunityOptions,
    pub price: f32,
    pub tax: u32,
    pub logo: Logo,
    pub homepage_url: Option<Url>,
    pub name: String,
    pub name_id: String,
    pub summary: String,
    pub description: Option<String>,
    pub description_plaintext: Option<String>,
    pub metadata_blob: Option<String>,
    pub profile_url: Url,
    #[serde(default, deserialize_with = "deserialize_empty_object")]
    pub modfile: Option<File>,
    pub media: Media,
    #[serde(rename = "metadata_kvp")]
    pub metadata: MetadataMap,
    pub tags: Vec<Tag>,
    pub dependencies: bool,
    pub stats: Statistics,
    pub platforms: Vec<Platform>,
}

newtype_enum! {
    /// See [Status & Visibility](https://docs.mod.io/#status-amp-visibility) docs for more information.
    pub struct Visibility: u8 {
        const HIDDEN = 0;
        const PUBLIC = 1;
    }
}

bitflags! {
    /// Community options a mod can enable.
    pub struct CommunityOptions: u16 {
        /// Comments enabled.
        const COMMENTS = 1;
        /// Previews enabled.
        const PREVIEWS = 64;
        /// Preview URLs enabled.
        const PREVIEW_URLS = 128;
        /// Allow mod dependencies
        const ALLOW_DEPENDENCIES = 1024;
    }

    /// Maturity options a mod can be flagged.
    ///
    /// This is only relevant if the parent game allows mods to be labelled as mature.
    pub struct MaturityOption: u8 {
        const ALCOHOL   = 1;
        const DRUGS     = 2;
        const VIOLENCE  = 4;
        const EXPLICIT  = 8;
    }
}

/// See the [Mod Event Object](https://docs.mod.io/#mod-event-object) docs for more information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Event {
    pub id: EventId,
    pub mod_id: ModId,
    pub user_id: UserId,
    pub date_added: u64,
    pub event_type: EventType,
}

newtype_enum! {
    /// Type of mod event that was triggered.
    #[derive(Deserialize)]
    #[serde(transparent)]
    pub struct EventType<24> {
        /// Primary file changed, the mod should be updated.
        const MODFILE_CHANGED     = b"MODFILE_CHANGED";
        /// Mod is marked as accepted and public.
        const MOD_AVAILABLE       = b"MOD_AVAILABLE";
        /// Mod is marked as not accepted, deleted or hidden.
        const MOD_UNAVAILABLE     = b"MOD_UNAVAILABLE";
        /// Mod has been updated.
        const MOD_EDITED          = b"MOD_EDITED";
        /// Mod has been permanently deleted.
        const MOD_DELETED         = b"MOD_DELETED";
        /// User has joined or left the mod team.
        const MOD_TEAM_CHANGED    = b"MOD_TEAM_CHANGED";
        /// A comment has been published for a mod.
        const MOD_COMMENT_ADDED   = b"MOD_COMMENT_ADDED";
        /// A comment has been deleted from a mod.
        const MOD_COMMENT_DELETED = b"MOD_COMMENT_DELETED";
    }
}

impl fmt::Display for EventType {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str(self.as_str())
    }
}

/// See the [Mod Dependency Object](https://docs.mod.io/#mod-dependencies-object) docs for more
/// information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Dependency {
    pub mod_id: ModId,
    pub date_added: u64,
}

/// See the [Mod Media Object](https://docs.mod.io/#mod-media-object) docs for more
/// information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Media {
    #[serde(default = "Vec::new")]
    pub youtube: Vec<String>,
    #[serde(default = "Vec::new")]
    pub sketchfab: Vec<String>,
    #[serde(default = "Vec::new")]
    pub images: Vec<Image>,
}

/// See the [Image Object](https://docs.mod.io/#image-object) docs for more information.
#[derive(Deserialize)]
#[non_exhaustive]
pub struct Image {
    pub filename: String,
    pub original: Url,
    pub thumb_320x180: Url,
}

impl fmt::Debug for Image {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Image")
            .field("filename", &self.filename)
            .field("original", &self.original.as_str())
            .field("thumb_320x180", &self.thumb_320x180.as_str())
            .finish()
    }
}

/// See the [Statistics Object](https://docs.mod.io/#mod-stats-object) docs for more
/// information.
#[derive(Debug)]
#[non_exhaustive]
pub struct Statistics {
    pub mod_id: ModId,
    pub downloads_today: u32,
    pub downloads_total: u32,
    pub subscribers_total: u32,
    pub popularity: Popularity,
    pub ratings: Ratings,
    pub date_expires: u64,
}

impl<'de> Deserialize<'de> for Statistics {
    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        #[derive(Deserialize)]
        #[serde(field_identifier, rename_all = "snake_case")]
        enum Field {
            ModId,
            DownloadsToday,
            DownloadsTotal,
            SubscribersTotal,
            PopularityRankPosition,
            PopularityRankTotalMods,
            RatingsTotal,
            RatingsPositive,
            RatingsNegative,
            RatingsPercentagePositive,
            RatingsWeightedAggregate,
            RatingsDisplayText,
            DateExpires,
            #[allow(dead_code)]
            Other(String),
        }

        struct StatisticsVisitor;

        impl<'de> Visitor<'de> for StatisticsVisitor {
            type Value = Statistics;

            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
                formatter.write_str("struct Statistics")
            }

            fn visit_map<A: MapAccess<'de>>(self, mut map: A) -> Result<Self::Value, A::Error> {
                let mut mod_id = None;
                let mut downloads_today = None;
                let mut downloads_total = None;
                let mut subscribers_total = None;
                let mut rank_position = None;
                let mut rank_total = None;
                let mut ratings_total = None;
                let mut ratings_positive = None;
                let mut ratings_negative = None;
                let mut ratings_percentage_positive = None;
                let mut ratings_weighted_aggregate = None;
                let mut ratings_display_text = None;
                let mut date_expires = None;

                while let Some(key) = map.next_key()? {
                    match key {
                        Field::ModId => {
                            mod_id.deserialize_value("mod_id", &mut map)?;
                        }
                        Field::DownloadsToday => {
                            downloads_today.deserialize_value("downloads_today", &mut map)?;
                        }
                        Field::DownloadsTotal => {
                            downloads_total.deserialize_value("downloads_total", &mut map)?;
                        }
                        Field::SubscribersTotal => {
                            subscribers_total.deserialize_value("subscribers_total", &mut map)?;
                        }
                        Field::PopularityRankPosition => {
                            rank_position
                                .deserialize_value("popularity_rank_position", &mut map)?;
                        }
                        Field::PopularityRankTotalMods => {
                            rank_total.deserialize_value("popularity_rank_total_mods", &mut map)?;
                        }
                        Field::RatingsTotal => {
                            ratings_total.deserialize_value("ratings_total", &mut map)?;
                        }
                        Field::RatingsPositive => {
                            ratings_positive.deserialize_value("ratings_positive", &mut map)?;
                        }
                        Field::RatingsNegative => {
                            ratings_negative.deserialize_value("ratings_negative", &mut map)?;
                        }
                        Field::RatingsPercentagePositive => {
                            ratings_percentage_positive
                                .deserialize_value("ratings_percentage_positive", &mut map)?;
                        }
                        Field::RatingsWeightedAggregate => {
                            ratings_weighted_aggregate
                                .deserialize_value("ratings_weighted_aggregate", &mut map)?;
                        }
                        Field::RatingsDisplayText => {
                            ratings_display_text
                                .deserialize_value("ratings_display_text", &mut map)?;
                        }
                        Field::DateExpires => {
                            date_expires.deserialize_value("date_expires", &mut map)?;
                        }
                        Field::Other(_) => {
                            map.next_value::<IgnoredAny>()?;
                        }
                    }
                }

                let mod_id = mod_id.missing_field("mod_id")?;
                let downloads_today = downloads_today.missing_field("downloads_today")?;
                let downloads_total = downloads_total.missing_field("downloads_total")?;
                let subscribers_total = subscribers_total.missing_field("subscribers_total")?;
                let rank_position = rank_position.missing_field("popularity_rank_position")?;
                let rank_total = rank_total.missing_field("popularity_rank_total_mods")?;
                let ratings_total = ratings_total.missing_field("ratings_total")?;
                let ratings_positive = ratings_positive.missing_field("ratings_positive")?;
                let ratings_negative = ratings_negative.missing_field("ratings_negative")?;
                let ratings_percentage_positive =
                    ratings_percentage_positive.missing_field("ratings_percentage_positive")?;
                let ratings_weighted_aggregate =
                    ratings_weighted_aggregate.missing_field("ratings_weighted_aggregate")?;
                let ratings_display_text =
                    ratings_display_text.missing_field("ratings_display_text")?;
                let date_expires = date_expires.missing_field("date_expires")?;

                Ok(Statistics {
                    mod_id,
                    downloads_today,
                    downloads_total,
                    subscribers_total,
                    popularity: Popularity {
                        rank_position,
                        rank_total,
                    },
                    ratings: Ratings {
                        total: ratings_total,
                        positive: ratings_positive,
                        negative: ratings_negative,
                        percentage_positive: ratings_percentage_positive,
                        weighted_aggregate: ratings_weighted_aggregate,
                        display_text: ratings_display_text,
                    },
                    date_expires,
                })
            }
        }

        deserializer.deserialize_map(StatisticsVisitor)
    }
}

/// Part of [`Statistics`]
#[derive(Debug)]
#[non_exhaustive]
pub struct Popularity {
    pub rank_position: u32,
    pub rank_total: u32,
}

/// Part of [`Statistics`]
#[derive(Debug)]
#[non_exhaustive]
pub struct Ratings {
    pub total: u32,
    pub positive: u32,
    pub negative: u32,
    pub percentage_positive: u32,
    pub weighted_aggregate: f32,
    pub display_text: String,
}

/// See the [Rating Object](https://docs.mod.io/#rating-object) docs for more information.
#[derive(Debug)]
#[non_exhaustive]
pub enum Rating {
    Positive {
        game_id: GameId,
        mod_id: ModId,
        date_added: u64,
    },
    Negative {
        game_id: GameId,
        mod_id: ModId,
        date_added: u64,
    },
}

impl<'de> Deserialize<'de> for Rating {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        use serde::de::Error;

        #[derive(Deserialize)]
        struct R {
            game_id: GameId,
            mod_id: ModId,
            rating: i8,
            date_added: u64,
        }

        match R::deserialize(deserializer) {
            Ok(R {
                game_id,
                mod_id,
                rating: 1,
                date_added,
            }) => Ok(Self::Positive {
                game_id,
                mod_id,
                date_added,
            }),
            Ok(R {
                game_id,
                mod_id,
                rating: -1,
                date_added,
            }) => Ok(Self::Negative {
                game_id,
                mod_id,
                date_added,
            }),
            Ok(R { rating, .. }) => {
                Err(D::Error::custom(format!("invalid rating value: {rating}")))
            }
            Err(e) => Err(e),
        }
    }
}

/// See the [Mod Platforms Object](https://docs.mod.io/#mod-platforms-object) docs for more information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Platform {
    #[serde(rename = "platform")]
    pub target: TargetPlatform,
    /// The unique id of the modfile that is currently live on the platform specified in the
    /// `target` field.
    #[serde(rename = "modfile_live")]
    pub modfile_id: FileId,
}

/// See the [Mod Tag Object](https://docs.mod.io/#mod-tag-object) docs for more information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Tag {
    pub name: String,
    pub date_added: u64,
}

impl fmt::Display for Tag {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.name.fmt(fmt)
    }
}

/// See the [Metadata KVP Object](https://docs.mod.io/#metadata-kvp-object) docs for more
/// information.
#[derive(Debug, Clone, Default, PartialEq)]
pub struct MetadataMap(HashMap<String, Vec<String>>);

impl MetadataMap {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn with_capacity(capacity: usize) -> Self {
        Self(HashMap::with_capacity(capacity))
    }
}

impl std::ops::Deref for MetadataMap {
    type Target = HashMap<String, Vec<String>>;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl std::ops::DerefMut for MetadataMap {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.0
    }
}

/// Deserialize a sequence of key-value objects to a `MetadataMap`.
///
/// ## Input
///
/// ```json
/// [
///     {"metakey": "pistol-dmg", "metavalue": "800"},
///     {"metakey": "smg-dmg", "metavalue": "1200"},
///     {"metakey": "pistol-dmg", "metavalue": "850"}
/// ]
/// ```
///
/// ## Result
///
/// ```text
/// MetadataMap({
///     "pistol-dmg": [
///         "800",
///         "850",
///     ],
///     "smg-dmg": [
///         "1200",
///     ],
/// })
/// ```
impl<'de> Deserialize<'de> for MetadataMap {
    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        #[derive(Debug)]
        enum ListField {
            Data,
            Other,
        }

        impl<'de> Deserialize<'de> for ListField {
            fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
                struct FieldVisitor;

                impl<'de> Visitor<'de> for FieldVisitor {
                    type Value = ListField;

                    fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
                        formatter.write_str("`data` field")
                    }

                    fn visit_str<E: serde::de::Error>(self, value: &str) -> Result<Self::Value, E> {
                        match value {
                            "data" => Ok(ListField::Data),
                            _ => Ok(ListField::Other),
                        }
                    }
                }

                deserializer.deserialize_identifier(FieldVisitor)
            }
        }

        struct MetadataVisitor;

        impl<'de> Visitor<'de> for MetadataVisitor {
            type Value = MetadataMap;

            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
                formatter.write_str("metadata kvp")
            }

            fn visit_map<A: MapAccess<'de>>(self, mut map: A) -> Result<Self::Value, A::Error> {
                let mut data = None;

                while let Some(key) = map.next_key()? {
                    match key {
                        ListField::Data => {
                            data.deserialize_value("data", &mut map)?;
                        }
                        ListField::Other => {
                            map.next_value::<IgnoredAny>()?;
                        }
                    }
                }

                let map = data.missing_field("data")?;
                Ok(map)
            }

            fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
                #[derive(Deserialize)]
                struct Element {
                    metakey: String,
                    metavalue: String,
                }

                let mut map = seq
                    .size_hint()
                    .map_or_else(MetadataMap::new, MetadataMap::with_capacity);

                while let Some(Element { metakey, metavalue }) = seq.next_element()? {
                    map.entry(metakey).or_default().push(metavalue);
                }

                Ok(map)
            }
        }

        deserializer.deserialize_any(MetadataVisitor)
    }
}

/// See the [Comment Object](https://docs.mod.io/#comment-object) docs for more information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct Comment {
    pub id: CommentId,
    pub resource_id: ResourceId,
    pub user: User,
    pub date_added: u64,
    pub reply_id: CommentId,
    pub thread_position: String,
    pub karma: i32,
    pub content: String,
}

/// See the [Team Member Object](https://docs.mod.io/#team-member-object) docs for more
/// information.
#[derive(Debug, Deserialize)]
#[non_exhaustive]
pub struct TeamMember {
    pub id: MemberId,
    pub user: User,
    pub level: TeamLevel,
    pub date_added: u64,
    pub position: String,
}

newtype_enum! {
    /// Defines the role of a team member.
    pub struct TeamLevel: u8 {
        const MODERATOR = 1;
        const CREATOR   = 4;
        const ADMIN     = 8;
    }
}

#[cfg(test)]
mod tests {
    use serde_test::{assert_de_tokens, Token};

    use super::{EventType, MetadataMap};
    use crate::types::List;

    #[test]
    fn metadata_from_result_list_serde() {
        #[derive(Debug, PartialEq, serde::Deserialize)]
        struct Entry {
            metakey: String,
            metavalue: String,
        }

        let list = List {
            data: vec![
                Entry {
                    metakey: "foo".to_owned(),
                    metavalue: "bar".to_owned(),
                },
                Entry {
                    metakey: "foo".to_owned(),
                    metavalue: "baz".to_owned(),
                },
            ],
            count: 2,
            offset: 0,
            limit: 100,
            total: 2,
        };

        let mut map = MetadataMap::new();
        map.entry("foo".to_owned())
            .or_insert(vec!["bar".to_owned(), "baz".to_owned()]);

        let tokens = &[
            Token::Struct {
                name: "List",
                len: 5,
            },
            Token::Str("data"),
            Token::Seq { len: Some(2) },
            Token::Map { len: Some(2) },
            Token::Str("metakey"),
            Token::Str("foo"),
            Token::Str("metavalue"),
            Token::Str("bar"),
            Token::MapEnd,
            Token::Map { len: Some(2) },
            Token::Str("metakey"),
            Token::Str("foo"),
            Token::Str("metavalue"),
            Token::Str("baz"),
            Token::MapEnd,
            Token::SeqEnd,
            Token::Str("result_count"),
            Token::U64(2),
            Token::Str("result_offset"),
            Token::U64(0),
            Token::Str("result_limit"),
            Token::U64(100),
            Token::Str("result_total"),
            Token::U64(2),
            Token::StructEnd,
        ];

        assert_de_tokens(&list, tokens);
        assert_de_tokens(&map, tokens);
    }

    #[test]
    fn metadata_from_mod_serde() {
        #[derive(Debug, PartialEq, serde::Deserialize)]
        struct Mod {
            id: u32,
            #[serde(rename = "metadata_kvp")]
            metadata: MetadataMap,
        }

        let mut map = MetadataMap::new();
        map.entry("foo".to_owned())
            .or_insert(vec!["bar".to_owned(), "baz".to_owned()]);

        let mod_ = Mod {
            id: 2,
            metadata: map,
        };
        assert_de_tokens(
            &mod_,
            &[
                Token::Struct {
                    name: "Mod",
                    len: 1,
                },
                Token::Str("id"),
                Token::U32(2),
                Token::Str("metadata_kvp"),
                Token::Seq { len: Some(2) },
                Token::Map { len: Some(2) },
                Token::Str("metakey"),
                Token::Str("foo"),
                Token::Str("metavalue"),
                Token::Str("bar"),
                Token::MapEnd,
                Token::Map { len: Some(2) },
                Token::Str("metakey"),
                Token::Str("foo"),
                Token::Str("metavalue"),
                Token::Str("baz"),
                Token::MapEnd,
                Token::SeqEnd,
                Token::StructEnd,
            ],
        );
    }

    #[test]
    fn mod_event_type_serde() {
        assert_de_tokens(
            &EventType::MODFILE_CHANGED,
            &[Token::Str("MODFILE_CHANGED")],
        );
        assert_de_tokens(&EventType::MOD_AVAILABLE, &[Token::Str("MOD_AVAILABLE")]);
        assert_de_tokens(
            &EventType::MOD_UNAVAILABLE,
            &[Token::Str("MOD_UNAVAILABLE")],
        );
        assert_de_tokens(&EventType::MOD_EDITED, &[Token::Str("MOD_EDITED")]);
        assert_de_tokens(&EventType::MOD_DELETED, &[Token::Str("MOD_DELETED")]);
        assert_de_tokens(
            &EventType::MOD_TEAM_CHANGED,
            &[Token::Str("MOD_TEAM_CHANGED")],
        );
        assert_de_tokens(
            &EventType::MOD_COMMENT_ADDED,
            &[Token::Str("MOD_COMMENT_ADDED")],
        );
        assert_de_tokens(
            &EventType::MOD_COMMENT_DELETED,
            &[Token::Str("MOD_COMMENT_DELETED")],
        );
        assert_de_tokens(&EventType::from_bytes(b"foo"), &[Token::Str("foo")]);
    }
}