use crate::sparql::eval::StringOrStoreString;
use crate::store::numeric_encoder::{
    EncodedQuad, EncodedTerm, Encoder, MemoryStrStore, StrContainer, StrLookup,
    ENCODED_DEFAULT_GRAPH,
};
use crate::store::StoreConnection;
use crate::Result;
use std::cell::{RefCell, RefMut};
use std::collections::BTreeSet;

pub type EncodedTuple = Vec<Option<EncodedTerm>>;

#[derive(Eq, PartialEq, Debug, Clone, Hash)]
pub enum PlanNode {
    Init,
    StaticBindings {
        tuples: Vec<EncodedTuple>,
    },
    QuadPatternJoin {
        child: Box<PlanNode>,
        subject: PatternValue,
        predicate: PatternValue,
        object: PatternValue,
        graph_name: PatternValue,
    },
    PathPatternJoin {
        child: Box<PlanNode>,
        subject: PatternValue,
        path: PlanPropertyPath,
        object: PatternValue,
        graph_name: PatternValue,
    },
    Join {
        left: Box<PlanNode>,
        right: Box<PlanNode>,
    },
    AntiJoin {
        left: Box<PlanNode>,
        right: Box<PlanNode>,
    },
    Filter {
        child: Box<PlanNode>,
        expression: PlanExpression,
    },
    Union {
        children: Vec<PlanNode>,
    },
    LeftJoin {
        left: Box<PlanNode>,
        right: Box<PlanNode>,
        possible_problem_vars: Vec<usize>, //Variables that should not be part of the entry of the left join
    },
    Extend {
        child: Box<PlanNode>,
        position: usize,
        expression: PlanExpression,
    },
    Sort {
        child: Box<PlanNode>,
        by: Vec<Comparator>,
    },
    HashDeduplicate {
        child: Box<PlanNode>,
    },
    Skip {
        child: Box<PlanNode>,
        count: usize,
    },
    Limit {
        child: Box<PlanNode>,
        count: usize,
    },
    Project {
        child: Box<PlanNode>,
        mapping: Vec<(usize, usize)>, // pairs of (variable key in child, variable key in output)
    },
    Aggregate {
        // By definition the group by key are the range 0..key_mapping.len()
        child: Box<PlanNode>,
        key_mapping: Vec<usize>, //index of the new key for each old key (that is the vec key)
        aggregates: Vec<(PlanAggregation, usize)>,
    },
}

impl PlanNode {
    pub fn variables(&self) -> BTreeSet<usize> {
        let mut set = BTreeSet::default();
        self.add_variables(&mut set);
        set
    }

    fn add_variables(&self, set: &mut BTreeSet<usize>) {
        match self {
            PlanNode::Init => (),
            PlanNode::StaticBindings { tuples } => {
                for tuple in tuples {
                    for (key, value) in tuple.iter().enumerate() {
                        if value.is_some() {
                            set.insert(key);
                        }
                    }
                }
            }
            PlanNode::QuadPatternJoin {
                child,
                subject,
                predicate,
                object,
                graph_name,
            } => {
                if let PatternValue::Variable(var) = subject {
                    set.insert(*var);
                }
                if let PatternValue::Variable(var) = predicate {
                    set.insert(*var);
                }
                if let PatternValue::Variable(var) = object {
                    set.insert(*var);
                }
                if let PatternValue::Variable(var) = graph_name {
                    set.insert(*var);
                }
                child.add_variables(set);
            }
            PlanNode::PathPatternJoin {
                child,
                subject,
                object,
                graph_name,
                ..
            } => {
                if let PatternValue::Variable(var) = subject {
                    set.insert(*var);
                }
                if let PatternValue::Variable(var) = object {
                    set.insert(*var);
                }
                if let PatternValue::Variable(var) = graph_name {
                    set.insert(*var);
                }
                child.add_variables(set);
            }
            PlanNode::Filter { child, expression } => {
                child.add_variables(set);
                expression.add_variables(set);
            }
            PlanNode::Union { children } => {
                for child in children {
                    child.add_variables(set);
                }
            }
            PlanNode::Join { left, right }
            | PlanNode::AntiJoin { left, right }
            | PlanNode::LeftJoin { left, right, .. } => {
                left.add_variables(set);
                right.add_variables(set);
            }
            PlanNode::Extend {
                child, position, ..
            } => {
                set.insert(*position);
                child.add_variables(set);
            }
            PlanNode::Sort { child, .. } => child.add_variables(set),
            PlanNode::HashDeduplicate { child } => child.add_variables(set),
            PlanNode::Skip { child, .. } => child.add_variables(set),
            PlanNode::Limit { child, .. } => child.add_variables(set),
            PlanNode::Project { child: _, mapping } => {
                for i in 0..mapping.len() {
                    set.insert(i);
                }
            }
            PlanNode::Aggregate {
                key_mapping,
                aggregates,
                ..
            } => {
                set.extend(key_mapping);
                for (_, var) in aggregates {
                    set.insert(*var);
                }
            }
        }
    }
}

#[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
pub enum PatternValue {
    Constant(EncodedTerm),
    Variable(usize),
}

impl PatternValue {
    pub fn is_var(&self) -> bool {
        match self {
            PatternValue::Constant(_) => false,
            PatternValue::Variable(_) => true,
        }
    }
}

#[derive(Eq, PartialEq, Debug, Clone, Hash)]
pub enum PlanExpression {
    Constant(EncodedTerm),
    Variable(usize),
    Exists(Box<PlanNode>),
    Or(Box<PlanExpression>, Box<PlanExpression>),
    And(Box<PlanExpression>, Box<PlanExpression>),
    Equal(Box<PlanExpression>, Box<PlanExpression>),
    NotEqual(Box<PlanExpression>, Box<PlanExpression>),
    Greater(Box<PlanExpression>, Box<PlanExpression>),
    GreaterOrEq(Box<PlanExpression>, Box<PlanExpression>),
    Lower(Box<PlanExpression>, Box<PlanExpression>),
    LowerOrEq(Box<PlanExpression>, Box<PlanExpression>),
    In(Box<PlanExpression>, Vec<PlanExpression>),
    Add(Box<PlanExpression>, Box<PlanExpression>),
    Sub(Box<PlanExpression>, Box<PlanExpression>),
    Mul(Box<PlanExpression>, Box<PlanExpression>),
    Div(Box<PlanExpression>, Box<PlanExpression>),
    UnaryPlus(Box<PlanExpression>),
    UnaryMinus(Box<PlanExpression>),
    UnaryNot(Box<PlanExpression>),
    Str(Box<PlanExpression>),
    Lang(Box<PlanExpression>),
    LangMatches(Box<PlanExpression>, Box<PlanExpression>),
    Datatype(Box<PlanExpression>),
    Bound(usize),
    IRI(Box<PlanExpression>),
    BNode(Option<Box<PlanExpression>>),
    Rand,
    Abs(Box<PlanExpression>),
    Ceil(Box<PlanExpression>),
    Floor(Box<PlanExpression>),
    Round(Box<PlanExpression>),
    Concat(Vec<PlanExpression>),
    SubStr(
        Box<PlanExpression>,
        Box<PlanExpression>,
        Option<Box<PlanExpression>>,
    ),
    StrLen(Box<PlanExpression>),
    Replace(
        Box<PlanExpression>,
        Box<PlanExpression>,
        Box<PlanExpression>,
        Option<Box<PlanExpression>>,
    ),
    UCase(Box<PlanExpression>),
    LCase(Box<PlanExpression>),
    EncodeForURI(Box<PlanExpression>),
    Contains(Box<PlanExpression>, Box<PlanExpression>),
    StrStarts(Box<PlanExpression>, Box<PlanExpression>),
    StrEnds(Box<PlanExpression>, Box<PlanExpression>),
    StrBefore(Box<PlanExpression>, Box<PlanExpression>),
    StrAfter(Box<PlanExpression>, Box<PlanExpression>),
    Year(Box<PlanExpression>),
    Month(Box<PlanExpression>),
    Day(Box<PlanExpression>),
    Hours(Box<PlanExpression>),
    Minutes(Box<PlanExpression>),
    Seconds(Box<PlanExpression>),
    Timezone(Box<PlanExpression>),
    Tz(Box<PlanExpression>),
    Now,
    UUID,
    StrUUID,
    MD5(Box<PlanExpression>),
    SHA1(Box<PlanExpression>),
    SHA256(Box<PlanExpression>),
    SHA384(Box<PlanExpression>),
    SHA512(Box<PlanExpression>),
    Coalesce(Vec<PlanExpression>),
    If(
        Box<PlanExpression>,
        Box<PlanExpression>,
        Box<PlanExpression>,
    ),
    StrLang(Box<PlanExpression>, Box<PlanExpression>),
    StrDT(Box<PlanExpression>, Box<PlanExpression>),
    SameTerm(Box<PlanExpression>, Box<PlanExpression>),
    IsIRI(Box<PlanExpression>),
    IsBlank(Box<PlanExpression>),
    IsLiteral(Box<PlanExpression>),
    IsNumeric(Box<PlanExpression>),
    Regex(
        Box<PlanExpression>,
        Box<PlanExpression>,
        Option<Box<PlanExpression>>,
    ),
    BooleanCast(Box<PlanExpression>),
    DoubleCast(Box<PlanExpression>),
    FloatCast(Box<PlanExpression>),
    DecimalCast(Box<PlanExpression>),
    IntegerCast(Box<PlanExpression>),
    DateCast(Box<PlanExpression>),
    TimeCast(Box<PlanExpression>),
    DateTimeCast(Box<PlanExpression>),
    StringCast(Box<PlanExpression>),
}

impl PlanExpression {
    fn add_variables(&self, set: &mut BTreeSet<usize>) {
        match self {
            PlanExpression::Constant(_)
            | PlanExpression::BNode(None)
            | PlanExpression::UUID
            | PlanExpression::StrUUID
            | PlanExpression::Rand
            | PlanExpression::Now => (),
            PlanExpression::Variable(v) | PlanExpression::Bound(v) => {
                set.insert(*v);
            }
            PlanExpression::UnaryPlus(e)
            | PlanExpression::UnaryMinus(e)
            | PlanExpression::UnaryNot(e)
            | PlanExpression::Str(e)
            | PlanExpression::Lang(e)
            | PlanExpression::Datatype(e)
            | PlanExpression::IRI(e)
            | PlanExpression::BNode(Some(e))
            | PlanExpression::Year(e)
            | PlanExpression::Month(e)
            | PlanExpression::Day(e)
            | PlanExpression::Hours(e)
            | PlanExpression::Minutes(e)
            | PlanExpression::Seconds(e)
            | PlanExpression::IsIRI(e)
            | PlanExpression::IsBlank(e)
            | PlanExpression::IsLiteral(e)
            | PlanExpression::IsNumeric(e)
            | PlanExpression::BooleanCast(e)
            | PlanExpression::DoubleCast(e)
            | PlanExpression::FloatCast(e)
            | PlanExpression::IntegerCast(e)
            | PlanExpression::DecimalCast(e)
            | PlanExpression::DateCast(e)
            | PlanExpression::TimeCast(e)
            | PlanExpression::DateTimeCast(e)
            | PlanExpression::StringCast(e)
            | PlanExpression::Abs(e)
            | PlanExpression::Ceil(e)
            | PlanExpression::Floor(e)
            | PlanExpression::Round(e)
            | PlanExpression::StrLen(e)
            | PlanExpression::UCase(e)
            | PlanExpression::LCase(e)
            | PlanExpression::EncodeForURI(e)
            | PlanExpression::Timezone(e)
            | PlanExpression::Tz(e)
            | PlanExpression::MD5(e)
            | PlanExpression::SHA1(e)
            | PlanExpression::SHA256(e)
            | PlanExpression::SHA384(e)
            | PlanExpression::SHA512(e) => {
                e.add_variables(set);
            }
            PlanExpression::Or(a, b)
            | PlanExpression::And(a, b)
            | PlanExpression::Equal(a, b)
            | PlanExpression::NotEqual(a, b)
            | PlanExpression::Greater(a, b)
            | PlanExpression::GreaterOrEq(a, b)
            | PlanExpression::Lower(a, b)
            | PlanExpression::LowerOrEq(a, b)
            | PlanExpression::Add(a, b)
            | PlanExpression::Sub(a, b)
            | PlanExpression::Mul(a, b)
            | PlanExpression::Div(a, b)
            | PlanExpression::SameTerm(a, b)
            | PlanExpression::LangMatches(a, b)
            | PlanExpression::StrLang(a, b)
            | PlanExpression::Contains(a, b)
            | PlanExpression::StrStarts(a, b)
            | PlanExpression::StrEnds(a, b)
            | PlanExpression::StrBefore(a, b)
            | PlanExpression::StrAfter(a, b)
            | PlanExpression::StrDT(a, b)
            | PlanExpression::Regex(a, b, None)
            | PlanExpression::SubStr(a, b, None) => {
                a.add_variables(set);
                b.add_variables(set);
            }
            PlanExpression::If(a, b, c)
            | PlanExpression::SubStr(a, b, Some(c))
            | PlanExpression::Replace(a, b, c, None)
            | PlanExpression::Regex(a, b, Some(c)) => {
                a.add_variables(set);
                b.add_variables(set);
                c.add_variables(set);
            }
            PlanExpression::Replace(a, b, c, Some(d)) => {
                a.add_variables(set);
                b.add_variables(set);
                c.add_variables(set);
                d.add_variables(set);
            }
            PlanExpression::Coalesce(l) | PlanExpression::Concat(l) => {
                for e in l {
                    e.add_variables(set);
                }
            }
            PlanExpression::In(e, l) => {
                e.add_variables(set);
                for e in l {
                    e.add_variables(set);
                }
            }
            PlanExpression::Exists(n) => n.add_variables(set),
        }
    }
}

#[derive(Eq, PartialEq, Debug, Clone, Hash)]
pub struct PlanAggregation {
    pub function: PlanAggregationFunction,
    pub parameter: Option<PlanExpression>,
    pub distinct: bool,
}

#[derive(Eq, PartialEq, Debug, Clone, Hash)]
pub enum PlanAggregationFunction {
    Count,
    Sum,
    Min,
    Max,
    Avg,
    Sample,
    GroupConcat { separator: String },
}

#[derive(Eq, PartialEq, Debug, Clone, Hash)]
pub enum PlanPropertyPath {
    PredicatePath(EncodedTerm),
    InversePath(Box<PlanPropertyPath>),
    SequencePath(Box<PlanPropertyPath>, Box<PlanPropertyPath>),
    AlternativePath(Box<PlanPropertyPath>, Box<PlanPropertyPath>),
    ZeroOrMorePath(Box<PlanPropertyPath>),
    OneOrMorePath(Box<PlanPropertyPath>),
    ZeroOrOnePath(Box<PlanPropertyPath>),
    NegatedPropertySet(Vec<EncodedTerm>),
}

#[derive(Eq, PartialEq, Debug, Clone, Hash)]
pub enum Comparator {
    Asc(PlanExpression),
    Desc(PlanExpression),
}

#[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
pub struct TripleTemplate {
    pub subject: TripleTemplateValue,
    pub predicate: TripleTemplateValue,
    pub object: TripleTemplateValue,
}

#[derive(Eq, PartialEq, Debug, Clone, Copy, Hash)]
pub enum TripleTemplateValue {
    Constant(EncodedTerm),
    BlankNode(usize),
    Variable(usize),
}

pub struct DatasetView<S: StoreConnection> {
    store: S,
    extra: RefCell<MemoryStrStore>,
    default_graph_as_union: bool,
}

impl<S: StoreConnection> DatasetView<S> {
    pub fn new(store: S, default_graph_as_union: bool) -> Self {
        Self {
            store,
            extra: RefCell::new(MemoryStrStore::default()),
            default_graph_as_union,
        }
    }

    pub fn quads_for_pattern<'a>(
        &'a self,
        subject: Option<EncodedTerm>,
        predicate: Option<EncodedTerm>,
        object: Option<EncodedTerm>,
        graph_name: Option<EncodedTerm>,
    ) -> Box<dyn Iterator<Item = Result<EncodedQuad>> + 'a> {
        if graph_name == None {
            Box::new(
                self.store
                    .quads_for_pattern(subject, predicate, object, None)
                    .filter(|quad| match quad {
                        Err(_) => true,
                        Ok(quad) => quad.graph_name != ENCODED_DEFAULT_GRAPH,
                    }),
            )
        } else if graph_name == Some(ENCODED_DEFAULT_GRAPH) && self.default_graph_as_union {
            Box::new(
                self.store
                    .quads_for_pattern(subject, predicate, object, None)
                    .map(|quad| {
                        let quad = quad?;
                        Ok(EncodedQuad::new(
                            quad.subject,
                            quad.predicate,
                            quad.object,
                            ENCODED_DEFAULT_GRAPH,
                        ))
                    }),
            )
        } else {
            self.store
                .quads_for_pattern(subject, predicate, object, graph_name)
        }
    }

    pub fn encoder<'a>(&'a self) -> impl Encoder + StrContainer + 'a {
        DatasetViewStrContainer {
            store: &self.store,
            extra: self.extra.borrow_mut(),
        }
    }
}

impl<S: StoreConnection> StrLookup for DatasetView<S> {
    type StrType = StringOrStoreString<S::StrType>;

    fn get_str(&self, id: u128) -> Result<Option<StringOrStoreString<S::StrType>>> {
        Ok(if let Some(value) = self.extra.borrow().get_str(id)? {
            Some(StringOrStoreString::String(value))
        } else if let Some(value) = self.store.get_str(id)? {
            Some(StringOrStoreString::Store(value))
        } else {
            None
        })
    }
}

struct DatasetViewStrContainer<'a, S: StoreConnection> {
    store: &'a S,
    extra: RefMut<'a, MemoryStrStore>,
}

impl<'a, S: StoreConnection> StrContainer for DatasetViewStrContainer<'a, S> {
    fn insert_str(&mut self, key: u128, value: &str) -> Result<()> {
        if self.store.get_str(key)?.is_none() {
            self.extra.insert_str(key, value)
        } else {
            Ok(())
        }
    }
}