use crate::{
    parser::{self, Annotation, Evaluation, Move, SetupInstr, Size, UnknownProperty},
    Color, Date, GameResult, GameType,
};
use std::{collections::HashSet, time::Duration};
use uuid::Uuid;

#[derive(Clone, Debug, PartialEq)]
pub enum GameError {
    InvalidGame,
    RequiredPropertiesMissing,
    InvalidGameNode(GameNodeError),
}

#[derive(Clone, Debug, PartialEq)]
pub enum MoveNodeError {
    IncompatibleProperty(parser::Property),
    ConflictingProperty,
    NotAMoveNode,
    ChildError(Box<GameNodeError>),
}

#[derive(Clone, Debug, PartialEq)]
pub enum SetupNodeError {
    IncompatibleProperty(parser::Property),
    ConflictingProperty,
    ConflictingPosition,
    NotASetupNode,
    ChildError(Box<GameNodeError>),
}

#[derive(Clone, Debug, PartialEq)]
pub enum GameNodeError {
    UnsupportedGameNode(MoveNodeError, SetupNodeError),
    ConflictingProperty,
    ConflictingPosition,
}

#[derive(Clone, Debug, PartialEq, Default)]
pub struct Player {
    pub name: Option<String>,
    pub rank: Option<String>,
    pub team: Option<String>,
}

/// This represents the more semantic version of the game parser. Where the `parser` crate pulls
/// out a raw set of nodes, this structure is guaranteed to be a well-formed game. Getting to this
/// level, the interpreter will reject any games that have setup properties and move properties
/// mixed in a single node. If there are other semantic problems, the interpreter will reject
/// those, as well. Where the function of the parser is to understand and correct fundamental
/// syntax issues, the result of the Game is to have a fully-understood game. However, this doesn't
/// (yet?) go quite to the level of apply the game type (i.e., this is Go, Chess, Yinsh, or
/// whatever).
#[derive(Clone, Debug, PartialEq)]
pub struct Game {
    game_type: GameType,

    // TODO: board size is not necessary in all games. Hive has no defined board size.
    board_size: Size,
    black_player: Player,
    white_player: Player,

    app: Option<String>,
    annotator: Option<String>,
    copyright: Option<String>,
    dates: Vec<Date>,
    event: Option<String>,
    game_name: Option<String>,
    extra_info: Option<String>,
    opening_info: Option<String>,
    location: Option<String>,
    result: Option<GameResult>,
    round: Option<String>,
    rules: Option<String>,
    source: Option<String>,
    time_limit: Option<Duration>,
    overtime: Option<String>,
    transcriber: Option<String>,

    children: Vec<GameNode>,
}

impl Game {
    pub fn new(
        game_type: GameType,
        board_size: Size,
        black_player: Player,
        white_player: Player,
    ) -> Self {
        Self {
            game_type,
            board_size,
            black_player,
            white_player,

            app: None,
            annotator: None,
            copyright: None,
            dates: vec![],
            event: None,
            game_name: None,
            extra_info: None,
            opening_info: None,
            location: None,
            result: None,
            round: None,
            rules: None,
            source: None,
            time_limit: None,
            overtime: None,
            transcriber: None,

            children: vec![],
        }
    }
}

impl Node for Game {
    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
        self.children.iter().collect::<Vec<&'a GameNode>>()
    }

    fn add_child<'a>(&'a mut self, node: GameNode) -> &'a mut GameNode {
        self.children.push(node);
        self.children.last_mut().unwrap()
    }
}

impl TryFrom<&parser::Tree> for Game {
    type Error = GameError;

    fn try_from(tree: &parser::Tree) -> Result<Self, Self::Error> {
        let mut ty = None;
        let mut size = None;
        let mut black_player = Player {
            name: None,
            rank: None,
            team: None,
        };
        let mut white_player = Player {
            name: None,
            rank: None,
            team: None,
        };

        for prop in tree.root.properties.iter() {
            match prop {
                parser::Property::GameType(ty_) => ty = Some(ty_.clone()),
                parser::Property::BoardSize(size_) => size = Some(size_.clone()),
                parser::Property::BlackPlayer(name) => {
                    black_player.name = Some(name.clone());
                }
                parser::Property::WhitePlayer(name) => {
                    white_player.name = Some(name.clone());
                }
                parser::Property::BlackRank(rank) => {
                    black_player.rank = Some(rank.clone());
                }
                parser::Property::WhiteRank(rank) => {
                    white_player.rank = Some(rank.clone());
                }
                parser::Property::BlackTeam(team) => {
                    black_player.team = Some(team.clone());
                }
                parser::Property::WhiteTeam(team) => {
                    white_player.team = Some(team.clone());
                }
                _ => {}
            }
        }

        let mut s = match (ty, size) {
            (Some(ty), Some(size)) => Ok(Self::new(ty, size, black_player, white_player)),
            _ => Err(Self::Error::RequiredPropertiesMissing),
        }?;

        for prop in tree.root.properties.iter() {
            match prop {
                parser::Property::GameType(_)
                | parser::Property::BoardSize(_)
                | parser::Property::BlackPlayer(_)
                | parser::Property::WhitePlayer(_)
                | parser::Property::BlackRank(_)
                | parser::Property::WhiteRank(_)
                | parser::Property::BlackTeam(_)
                | parser::Property::WhiteTeam(_) => {}
                parser::Property::Application(v) => s.app = Some(v.clone()),
                parser::Property::Annotator(v) => s.annotator = Some(v.clone()),
                parser::Property::Copyright(v) => s.copyright = Some(v.clone()),
                parser::Property::EventDates(v) => s.dates = v.clone(),
                parser::Property::EventName(v) => s.event = Some(v.clone()),
                parser::Property::GameName(v) => s.game_name = Some(v.clone()),
                parser::Property::ExtraGameInformation(v) => s.extra_info = Some(v.clone()),
                parser::Property::GameOpening(v) => s.opening_info = Some(v.clone()),
                parser::Property::GameLocation(v) => s.location = Some(v.clone()),
                parser::Property::Result(v) => s.result = Some(v.clone()),
                parser::Property::Round(v) => s.round = Some(v.clone()),
                parser::Property::Ruleset(v) => s.rules = Some(v.clone()),
                parser::Property::Source(v) => s.source = Some(v.clone()),
                parser::Property::TimeLimit(v) => s.time_limit = Some(v.clone()),
                parser::Property::Overtime(v) => s.overtime = Some(v.clone()),
                // parser::Property::Data(v) => s.transcriber = Some(v.clone()),
                _ => {}
            }
        }

        s.children = tree
            .root
            .next
            .iter()
            .map(|node| GameNode::try_from(node))
            .collect::<Result<Vec<GameNode>, GameNodeError>>()
            .map_err(GameError::InvalidGameNode)?;

        Ok(s)
    }
}

#[derive(Clone, Debug, PartialEq)]
pub enum GameNode {
    MoveNode(MoveNode),
    SetupNode(SetupNode),
}

pub trait Node {
    /// Provide a pre-order traversal of all of the nodes in the game tree.
    fn nodes<'a>(&'a self) -> Vec<&'a GameNode> {
        self.children()
            .iter()
            .map(|node| {
                let mut children = node.nodes();
                let mut v = vec![*node];
                v.append(&mut children);
                v
            })
            .flatten()
            .collect::<Vec<&'a GameNode>>()
    }

    fn children<'a>(&'a self) -> Vec<&'a GameNode>;
    fn add_child<'a>(&'a mut self, node: GameNode) -> &'a mut GameNode;
}

impl GameNode {
    pub fn id(&self) -> Uuid {
        match self {
            GameNode::MoveNode(node) => node.id,
            GameNode::SetupNode(node) => node.id,
        }
    }
}

impl Node for GameNode {
    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
        match self {
            GameNode::MoveNode(node) => node.children(),
            GameNode::SetupNode(node) => node.children(),
        }
    }

    fn nodes<'a>(&'a self) -> Vec<&'a GameNode> {
        match self {
            GameNode::MoveNode(node) => node.nodes(),
            GameNode::SetupNode(node) => node.nodes(),
        }
    }

    fn add_child<'a>(&'a mut self, new_node: GameNode) -> &'a mut GameNode {
        match self {
            GameNode::MoveNode(node) => node.add_child(new_node),
            GameNode::SetupNode(node) => node.add_child(new_node),
        }
    }
}

impl TryFrom<&parser::Node> for GameNode {
    type Error = GameNodeError;

    fn try_from(n: &parser::Node) -> Result<Self, Self::Error> {
        // I originally wrote this recursively. However, on an ordinary game of a couple hundred
        // moves, that meant that I was recursing 500 functions, and that exceeded the stack limit.
        // So, instead, I need to unroll everything to non-recursive form.
        //
        // So, I can treat each branch of the tree as a single line. Iterate over that line. I can
        // only use the MoveNode::try_from and SetupNode::try_from if those functions don't
        // recurse. Instead, I'm going to process just that node, then return to here and process
        // the children.
        let move_node = MoveNode::try_from(n);
        let setup_node = SetupNode::try_from(n);

        // I'm much too tired when writing this. I'm still recursing, but I did cut the number of
        // recursions in half. This helps, but it still doesn't guarantee that I'm going to be able
        // to parse all possible games. So, still, treat each branch of the game as a single line.
        // Iterate over that line, don't recurse. Create bookmarks at each branch point, and then
        // come back to each one.
        let children = n
            .next
            .iter()
            .map(|n| GameNode::try_from(n))
            .collect::<Result<Vec<Self>, Self::Error>>()?;

        let node = match (move_node, setup_node) {
            (Ok(mut node), _) => {
                node.children = children;
                Ok(Self::MoveNode(node))
            }
            (Err(_), Ok(mut node)) => {
                node.children = children;
                Ok(Self::SetupNode(node))
            }
            (Err(move_err), Err(setup_err)) => {
                Err(Self::Error::UnsupportedGameNode(move_err, setup_err))
            }
        }?;

        Ok(node)
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct MoveNode {
    id: Uuid,
    color: Color,
    mv: Move,
    children: Vec<GameNode>,

    time_left: Option<Duration>,
    moves_left: Option<usize>,
    name: Option<String>,
    evaluation: Option<Evaluation>,
    value: Option<f64>,
    comments: Option<String>,
    annotation: Option<Annotation>,
    unknown_props: Vec<(String, String)>,
}

impl MoveNode {
    pub fn new(color: Color, mv: Move) -> Self {
        Self {
            id: Uuid::new_v4(),
            color,
            mv,
            children: Vec::new(),

            time_left: None,
            moves_left: None,
            name: None,
            evaluation: None,
            value: None,
            comments: None,
            annotation: None,
            unknown_props: vec![],
        }
    }
}

impl Node for MoveNode {
    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
        self.children.iter().collect::<Vec<&'a GameNode>>()
    }

    fn add_child<'a>(&'a mut self, node: GameNode) -> &'a mut GameNode {
        self.children.push(node);
        self.children.last_mut().unwrap()
    }
}

impl TryFrom<&parser::Node> for MoveNode {
    type Error = MoveNodeError;

    fn try_from(n: &parser::Node) -> Result<Self, Self::Error> {
        let s = match n.mv() {
            Some((color, mv)) => {
                let mut s = Self::new(color, mv);

                for prop in n.properties.iter() {
                    match prop {
                        parser::Property::Move((color, mv)) => {
                            if s.color != *color || s.mv != *mv {
                                return Err(Self::Error::ConflictingProperty);
                            }
                        }
                        parser::Property::TimeLeft((color, duration)) => {
                            if s.color != *color {
                                return Err(Self::Error::ConflictingProperty);
                            }
                            if s.time_left.is_some() {
                                return Err(Self::Error::ConflictingProperty);
                            }
                            s.time_left = Some(duration.clone());
                        }
                        parser::Property::Comment(cmt) => {
                            if s.comments.is_some() {
                                return Err(Self::Error::ConflictingProperty);
                            }
                            s.comments = Some(cmt.clone());
                        }
                        parser::Property::Evaluation(evaluation) => {
                            if s.evaluation.is_some() {
                                return Err(Self::Error::ConflictingProperty);
                            }
                            s.evaluation = Some(*evaluation)
                        }
                        parser::Property::Annotation(annotation) => {
                            if s.annotation.is_some() {
                                return Err(Self::Error::ConflictingProperty);
                            }
                            s.annotation = Some(*annotation)
                        }
                        parser::Property::Territory(..) => {
                            eprintln!("not processing territory property");
                        }
                        parser::Property::Unknown(UnknownProperty { ident, value }) => {
                            s.unknown_props.push((ident.clone(), value.clone()));
                        }
                        _ => return Err(Self::Error::IncompatibleProperty(prop.clone())),
                    }
                }

                Ok(s)
            }
            None => Err(Self::Error::NotAMoveNode),
        }?;

        Ok(s)
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct SetupNode {
    id: Uuid,

    positions: Vec<parser::SetupInstr>,
    children: Vec<GameNode>,
}

impl SetupNode {
    pub fn new(positions: Vec<parser::SetupInstr>) -> Result<Self, SetupNodeError> {
        let mut board = HashSet::new();
        for position in positions.iter() {
            let point = match position {
                SetupInstr::Piece((_, point)) => point,
                SetupInstr::Clear(point) => point,
            };
            if board.contains(point) {
                return Err(SetupNodeError::ConflictingPosition);
            }
            board.insert(point);
        }

        Ok(Self {
            id: Uuid::new_v4(),
            positions,
            children: Vec::new(),
        })
    }
}

impl Node for SetupNode {
    fn children<'a>(&'a self) -> Vec<&'a GameNode> {
        self.children.iter().collect::<Vec<&'a GameNode>>()
    }

    #[allow(dead_code)]
    fn add_child<'a>(&'a mut self, _node: GameNode) -> &'a mut GameNode {
        unimplemented!()
    }
}

impl TryFrom<&parser::Node> for SetupNode {
    type Error = SetupNodeError;

    fn try_from(n: &parser::Node) -> Result<Self, Self::Error> {
        match n.setup() {
            Some(elements) => Self::new(elements),
            None => Err(Self::Error::NotASetupNode),
        }
    }
}

#[allow(dead_code)]
pub fn path_to_node<'a>(node: &'a GameNode, id: Uuid) -> Vec<&'a GameNode> {
    if node.id() == id {
        return vec![node];
    }

    for child in node.children() {
        let mut path = path_to_node(child, id);
        if path.len() > 1 {
            path.push(child);
            return path;
        }
    }

    Vec::new()
}

#[cfg(test)]
mod test {
    use super::*;
    use cool_asserts::assert_matches;

    #[test]
    fn it_can_create_an_empty_game_tree() {
        let tree = Game::new(
            GameType::Go,
            Size {
                width: 19,
                height: 19,
            },
            Player::default(),
            Player::default(),
        );
        assert_eq!(tree.nodes().len(), 0);
    }

    #[test]
    fn it_can_add_moves_to_a_game() {
        let mut game = Game::new(
            GameType::Go,
            Size {
                width: 19,
                height: 19,
            },
            Player::default(),
            Player::default(),
        );

        let first_move = MoveNode::new(Color::Black, Move::Move("dd".to_owned()));
        let first_ = game.add_child(GameNode::MoveNode(first_move.clone()));
        let second_move = MoveNode::new(Color::White, Move::Move("qq".to_owned()));
        first_.add_child(GameNode::MoveNode(second_move.clone()));

        let nodes = game.nodes();
        assert_eq!(nodes.len(), 2);
        assert_eq!(nodes[0].id(), first_move.id);
        assert_eq!(nodes[1].id(), second_move.id);
    }

    #[ignore]
    #[test]
    fn it_can_set_up_a_game() {
        unimplemented!()
    }

    #[ignore]
    #[test]
    fn it_can_load_tree_from_sgf() {
        unimplemented!()
    }

    #[test]
    fn game_node_can_parse_sgf_move_node() {
        let n = parser::Node {
            properties: vec![
                parser::Property::Move((Color::White, Move::Move("dp".to_owned()))),
                parser::Property::TimeLeft((Color::White, Duration::from_secs(176))),
                parser::Property::Comment("Comments in the game".to_owned()),
            ],
            next: vec![],
        };
        assert_matches!(GameNode::try_from(&n), Ok(GameNode::MoveNode(_)));
    }
}

#[cfg(test)]
mod root_node_tests {
    #[ignore]
    #[test]
    fn it_rejects_move_properties() {
        unimplemented!()
    }

    #[ignore]
    #[test]
    fn it_rejects_setup_properties() {
        unimplemented!()
    }

    #[ignore]
    #[test]
    fn it_can_parse_a_root_sgf() {
        unimplemented!()
    }
}

#[cfg(test)]
mod move_node_tests {
    use crate::parser::PositionList;

    use super::*;
    use cool_asserts::assert_matches;

    #[test]
    fn it_can_parse_an_sgf_move_node() {
        let n = parser::Node {
            properties: vec![
                parser::Property::Move((Color::White, Move::Move("dp".to_owned()))),
                parser::Property::TimeLeft((Color::White, Duration::from_secs(176))),
                parser::Property::Comment("Comments in the game".to_owned()),
            ],
            next: vec![],
        };
        assert_matches!(MoveNode::try_from(&n), Ok(node) => {
            assert_eq!(node.color, Color::White);
            assert_eq!(node.mv, Move::Move("dp".to_owned()));
            assert_eq!(node.children, vec![]);
            assert_eq!(node.time_left, Some(Duration::from_secs(176)));
            assert_eq!(node.comments, Some("Comments in the game".to_owned()));
        });
    }

    #[test]
    fn it_rejects_an_sgf_setup_node() {
        let n = parser::Node {
            properties: vec![
                parser::Property::Move((Color::White, Move::Move("dp".to_owned()))),
                parser::Property::TimeLeft((Color::White, Duration::from_secs(176))),
                parser::Property::SetupBlackStones(PositionList(vec![
                    "dd".to_owned(),
                    "de".to_owned(),
                ])),
            ],
            next: vec![],
        };
        assert_matches!(
            MoveNode::try_from(&n),
            Err(MoveNodeError::IncompatibleProperty(_))
        );
    }
}

#[cfg(test)]
mod setup_node_tests {
    use crate::parser::SetupInstr;

    use super::*;
    use cool_asserts::assert_matches;

    #[ignore]
    #[test]
    fn it_can_parse_an_sgf_setup_node() {
        unimplemented!()
    }

    #[test]
    fn it_rejects_conflicting_placement_properties() {
        assert_matches!(
            SetupNode::new(vec![
                SetupInstr::Piece((Color::Black, "dd".to_owned())),
                SetupInstr::Piece((Color::Black, "dd".to_owned())),
            ]),
            Err(SetupNodeError::ConflictingPosition)
        );
        assert_matches!(
            SetupNode::new(vec![
                SetupInstr::Piece((Color::Black, "dd".to_owned())),
                SetupInstr::Piece((Color::Black, "ee".to_owned())),
                SetupInstr::Piece((Color::White, "ee".to_owned())),
            ]),
            Err(SetupNodeError::ConflictingPosition)
        );
    }
}

#[cfg(test)]
mod path_test {
    #[ignore]
    #[test]
    fn returns_empty_list_if_no_game_nodes() {
        unimplemented!()
    }

    #[ignore]
    #[test]
    fn returns_empty_list_if_node_not_found() {
        unimplemented!()
    }

    #[ignore]
    #[test]
    fn path_excludes_root_node() {
        unimplemented!()
    }
}

#[cfg(test)]
mod file_test {
    use super::*;
    use crate::Win;
    use cool_asserts::assert_matches;
    use parser::parse_collection;
    use std::{fs::File, io::Read};

    fn with_text(text: &str, f: impl FnOnce(Vec<Game>)) {
        let (_, games) = parse_collection::<nom::error::VerboseError<&str>>(text).unwrap();
        let games = games
            .into_iter()
            .map(|game| Game::try_from(&game).expect("game to parse"))
            .collect::<Vec<Game>>();
        f(games);
    }

    fn with_file(path: &std::path::Path, f: impl FnOnce(Vec<Game>)) {
        let mut file = File::open(path).unwrap();
        let mut text = String::new();
        let _ = file.read_to_string(&mut text);
        with_text(&text, f);
    }

    /// This test checks against an ordinary game from SGF. It is unannotated and should contain
    /// only move nodes with no setup nodes. The original source is from a game I played on KGS.
    #[test]
    fn it_can_load_an_ordinary_unannotated_game() {
        with_file(
            std::path::Path::new("test_data/2020 USGO DDK, Round 1.sgf"),
            |games| {
                assert_eq!(games.len(), 1);
                let game = &games[0];

                assert_eq!(game.game_type, GameType::Go);
                assert_eq!(
                    game.board_size,
                    Size {
                        width: 19,
                        height: 19
                    }
                );
                assert_eq!(
                    game.black_player,
                    Player {
                        name: Some("savanni".to_owned()),
                        rank: Some("23k".to_owned()),
                        team: None
                    }
                );
                assert_eq!(
                    game.white_player,
                    Player {
                        name: Some("Geckoz".to_owned()),
                        rank: None,
                        team: None
                    }
                );
                assert_eq!(game.app, Some("CGoban:3".to_owned()));

                assert_eq!(game.annotator, None);
                assert_eq!(game.copyright, None);
                assert_eq!(
                    game.dates,
                    vec![Date::Date(
                        chrono::NaiveDate::from_ymd_opt(2020, 8, 5).unwrap()
                    )]
                );
                assert_eq!(game.event, None);
                assert_eq!(game.game_name, None);
                assert_eq!(game.extra_info, None);
                assert_eq!(game.opening_info, None);
                assert_eq!(
                    game.location,
                    Some("The KGS Go Server at http://www.gokgs.com/".to_owned())
                );
                assert_eq!(game.result, Some(GameResult::White(Win::Score(17.5))));
                assert_eq!(game.round, None);
                assert_eq!(game.rules, Some("AGA".to_owned()));
                assert_eq!(game.source, None);
                assert_eq!(game.time_limit, Some(Duration::from_secs(1800)));
                assert_eq!(game.overtime, Some("5x30 byo-yomi".to_owned()));
                assert_eq!(game.transcriber, None);

                /*
                    Property {
                        ident: "KM".to_owned(),
                        values: vec!["7.50".to_owned()],
                    },
                ];

                for i in 0..16 {
                    assert_eq!(node.properties[i], expected_properties[i]);
                }
                */

                let children = game.children();
                let node = children.first().unwrap();
                assert_matches!(node, GameNode::MoveNode(node) => {
                    assert_eq!(node.color, Color::Black);
                    assert_eq!(node.mv, Move::Move("pp".to_owned()));
                    assert_eq!(node.time_left, Some(Duration::from_secs(1795)));
                    assert_eq!(node.comments, Some("Geckoz [?]: Good game\nsavanni [23k?]: There we go! This UI is... tough.\nsavanni [23k?]: Have fun! Talk to you at the end.\nGeckoz [?]: Yeah, OGS is much better; I'm a UX professional\n".to_owned())
                )});

                let children = node.children();
                let node = children.first().unwrap();
                assert_matches!(node, GameNode::MoveNode(node) => {
                    assert_eq!(node.color, Color::White);
                    assert_eq!(node.mv, Move::Move("dp".to_owned()));
                    assert_eq!(node.time_left, Some(Duration::from_secs(1765)));
                    assert_eq!(node.comments, None);
                });
                /*
                let node = node.next().unwrap();
                let expected_properties = vec![
                    Property {
                        ident: "W".to_owned(),
                        values: vec!["dp".to_owned()],
                    },
                    Property {
                        ident: "WL".to_owned(),
                        values: vec!["1765.099".to_owned()],
                    },
                ];
                for i in 0..2 {
                    assert_eq!(node.properties[i], expected_properties[i]);
                }
                */
            },
        );
    }
}