use crate::parser::Filter;
use crate::parser::KVPair;
use crate::parser::OwnedLiteral;
use crate::parser::PartialNameElement;
use crate::parser::RValue;
use crate::renderer::breadcrumb_tree::BreadcrumbTreeElement;
use crate::renderer::context_element::CompareContextElement;
use crate::renderer::context_element::ContextElement;
use crate::renderer::context_element::IceResult;
use crate::renderer::context_element::IntoContextElement;
use crate::renderer::math::MathNumber;
use crate::renderer::walking::walk_path;
use crate::renderer::Castable;
use crate::renderer::DustRenderer;
use crate::renderer::Loopable;
use crate::renderer::RenderError;
use crate::renderer::Renderable;
use crate::renderer::Sizable;
use crate::renderer::Truthiness;
use crate::renderer::WalkError;
use crate::renderer::Walkable;
use std::borrow::Borrow;
use std::cmp::Ordering;
use std::collections::HashMap;
use std::convert::TryInto;

#[derive(Debug)]
pub struct ParametersContext<'a> {
    parent: Option<&'a ParametersContext<'a>>,
    params: HashMap<&'a str, (&'a RValue<'a>, Option<BreadcrumbTreeElement<'a>>)>,
}

impl<'a> ParametersContext<'a> {
    pub fn new(
        renderer: &DustRenderer,
        breadcrumbs: &'a Vec<BreadcrumbTreeElement<'a>>,
        params: &'a Vec<KVPair>,
        parent: Option<&'a ParametersContext<'a>>,
    ) -> Self {
        // If the parameter is a Path, then we resolve it immediately
        // to a context element because those are resolved using the
        // breadcrumbs at the time of assignment.
        //
        // If the parameter is a template (for example `foo="{bar}"`)
        // then those are resolved at the time of access rather than
        // the time of assignment, so we leave them into their
        // original IntoContextElement state.
        let rendered_params: HashMap<&'a str, (&'a RValue<'a>, Option<BreadcrumbTreeElement<'a>>)> =
            params
                .iter()
                .map(|kvpair| {
                    let k = kvpair.key;
                    let v: Option<BreadcrumbTreeElement<'a>> = match &kvpair.value {
                        RValue::RVLiteral(_owned_literal) => {
                            Some(BreadcrumbTreeElement::from_borrowed(&kvpair.value))
                        }
                        RValue::RVPath(_path) => kvpair
                            .value
                            .into_context_element(renderer, breadcrumbs)
                            .map(std::convert::From::from),
                        RValue::RVTemplate(_template) => {
                            Some(BreadcrumbTreeElement::from_borrowed(&kvpair.value))
                        }
                    };
                    (k, (&kvpair.value, v))
                })
                .collect();

        ParametersContext {
            parent: parent,
            params: rendered_params,
        }
    }

    pub fn from_values(
        parent: Option<&'a ParametersContext<'a>>,
        params: HashMap<&'a str, (&'a RValue<'a>, Option<BreadcrumbTreeElement<'a>>)>,
    ) -> Self {
        ParametersContext {
            parent: parent,
            params: params,
        }
    }

    pub fn contains_key(&self, segment: &str) -> bool {
        self.params.contains_key(segment)
            || self
                .parent
                .map(|p| p.contains_key(segment))
                .unwrap_or(false)
    }

    pub fn get_original_rvalue(&self, segment: &str) -> Option<&'a RValue<'a>> {
        self.params
            .get(segment)
            .map(|(rvalue, _bte)| *rvalue)
            .or_else(|| {
                self.parent
                    .map(|p| p.get_original_rvalue(segment))
                    .flatten()
            })
    }
}

impl<'a> IntoContextElement for ParametersContext<'a> {
    fn into_context_element<'b>(
        &'b self,
        _renderer: &DustRenderer,
        _breadcrumbs: &'b Vec<BreadcrumbTreeElement<'b>>,
    ) -> Option<IceResult<'b>> {
        panic!("into_context_element cannot be called on pseudo elements");
    }
}

impl<'a> Walkable for ParametersContext<'a> {
    fn walk(&self, segment: &str) -> Result<&dyn IntoContextElement, WalkError> {
        match self.params.get(segment).map(|(_rvalue, bte)| bte) {
            Some(Some(bte)) => Ok(bte.borrow()),
            Some(None) => Err(WalkError::CantWalk),
            None => self
                .parent
                .map(|p| p.walk(segment))
                .unwrap_or(Err(WalkError::CantWalk)),
        }
    }

    fn is_pseudo_element(&self) -> bool {
        true
    }
}

impl<'a> IntoContextElement for RValue<'a> {
    fn into_context_element<'b>(
        &'b self,
        renderer: &DustRenderer,
        breadcrumbs: &'b Vec<BreadcrumbTreeElement<'b>>,
    ) -> Option<IceResult<'b>> {
        match self {
            RValue::RVLiteral(owned_literal) => Some(IceResult::from_borrowed(owned_literal)),
            RValue::RVPath(path) => walk_path(breadcrumbs, &path.keys)
                .map(|ice| ice.into_context_element(renderer, breadcrumbs))
                .ok()
                .flatten(),
            RValue::RVTemplate(template) => renderer
                .render_partial_name(template, breadcrumbs)
                .map(|rendered| OwnedLiteral::LString(rendered))
                .ok()
                .map(|owned_literal| IceResult::from_owned(owned_literal)),
        }
    }
}

impl<'a> Walkable for RValue<'a> {
    fn walk(&self, _segment: &str) -> Result<&dyn IntoContextElement, WalkError> {
        Err(WalkError::CantWalk)
    }
}

impl ContextElement for OwnedLiteral {}

impl Truthiness for OwnedLiteral {
    fn is_truthy(&self) -> bool {
        match self {
            OwnedLiteral::LString(text) => !text.is_empty(),
            OwnedLiteral::LPositiveInteger(_num) => true,
            OwnedLiteral::LNegativeInteger(_num) => true,
            OwnedLiteral::LFloat(_num) => true,
        }
    }
}

impl Renderable for OwnedLiteral {
    fn render(&self, _filters: &Vec<Filter>) -> Result<String, RenderError> {
        match self {
            OwnedLiteral::LString(text) => Ok(text.clone()),
            OwnedLiteral::LPositiveInteger(num) => Ok(num.to_string()),
            OwnedLiteral::LNegativeInteger(num) => Ok(num.to_string()),
            OwnedLiteral::LFloat(num) => Ok(num.to_string()),
        }
    }
}

impl Loopable for OwnedLiteral {
    fn get_loop_elements(&self) -> Vec<&dyn ContextElement> {
        Vec::new()
    }
}

impl Walkable for OwnedLiteral {
    fn walk(&self, _segment: &str) -> Result<&dyn IntoContextElement, WalkError> {
        Err(WalkError::CantWalk)
    }
}

impl Sizable for OwnedLiteral {
    fn get_size<'a>(&'a self) -> Option<IceResult<'a>> {
        match self {
            OwnedLiteral::LFloat(_) => Some(IceResult::from_borrowed(self)),
            OwnedLiteral::LPositiveInteger(_) => Some(IceResult::from_borrowed(self)),
            OwnedLiteral::LNegativeInteger(_) => Some(IceResult::from_borrowed(self)),
            OwnedLiteral::LString(text) => Some(IceResult::from_owned(
                OwnedLiteral::LPositiveInteger(text.len().try_into().unwrap()),
            )),
        }
    }
}

impl Castable for OwnedLiteral {
    fn cast_to_type<'a>(&'a self, target: &str) -> Option<IceResult<'a>> {
        match (self, target) {
            (OwnedLiteral::LString(text), "number") => text
                .parse::<u64>()
                .map(|num| IceResult::from_owned(OwnedLiteral::LPositiveInteger(num)))
                .or_else(|_| {
                    text.parse::<i64>()
                        .map(|num| IceResult::from_owned(OwnedLiteral::LNegativeInteger(num)))
                })
                .or_else(|_| {
                    text.parse::<f64>()
                        .map(|num| IceResult::from_owned(OwnedLiteral::LFloat(num)))
                })
                .ok(),
            (OwnedLiteral::LPositiveInteger(_), "number") => Some(IceResult::from_borrowed(self)),
            (OwnedLiteral::LNegativeInteger(_), "number") => Some(IceResult::from_borrowed(self)),
            (OwnedLiteral::LFloat(_), "number") => Some(IceResult::from_borrowed(self)),
            (_, _) => panic!("Unimplemented cast"),
        }
    }
}

impl CompareContextElement for OwnedLiteral {
    fn equals(&self, other: &dyn ContextElement) -> bool {
        // println!("Literal equality check {:?} == {:?}", self, other);
        // If its an OwnedLiteral then compare them directly,
        // otherwise defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => other.equals(self),
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(self_text), OwnedLiteral::LString(other_text)) => {
                    self_text == other_text
                }
                (
                    OwnedLiteral::LPositiveInteger(self_num),
                    OwnedLiteral::LPositiveInteger(other_num),
                ) => self_num == other_num,
                (
                    OwnedLiteral::LNegativeInteger(self_num),
                    OwnedLiteral::LNegativeInteger(other_num),
                ) => self_num == other_num,
                (OwnedLiteral::LString(_self_text), _) | (_, OwnedLiteral::LString(_self_text)) => {
                    false
                }
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LFloat(other_num)) => {
                    self_num == other_num
                }
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LPositiveInteger(other_num)) => {
                    *self_num == (*other_num as f64)
                }
                (OwnedLiteral::LPositiveInteger(self_num), OwnedLiteral::LFloat(other_num)) => {
                    (*self_num as f64) == *other_num
                }
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LNegativeInteger(other_num)) => {
                    *self_num == (*other_num as f64)
                }
                (OwnedLiteral::LNegativeInteger(self_num), OwnedLiteral::LFloat(other_num)) => {
                    (*self_num as f64) == *other_num
                }
                (
                    OwnedLiteral::LPositiveInteger(self_num),
                    OwnedLiteral::LNegativeInteger(other_num),
                ) => {
                    if *self_num < std::i64::MAX as u64 {
                        (*self_num as i64) == *other_num
                    } else {
                        false
                    }
                }
                (
                    OwnedLiteral::LNegativeInteger(self_num),
                    OwnedLiteral::LPositiveInteger(other_num),
                ) => {
                    if *other_num < std::i64::MAX as u64 {
                        *self_num == (*other_num as i64)
                    } else {
                        false
                    }
                }
            },
        }
    }

    fn partial_compare(&self, other: &dyn ContextElement) -> Option<Ordering> {
        // If its an OwnedLiteral then compare them directly,
        // otherwise defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => match other.partial_compare(self) {
                None => None,
                Some(ord) => match ord {
                    Ordering::Equal => Some(Ordering::Equal),
                    Ordering::Greater => Some(Ordering::Less),
                    Ordering::Less => Some(Ordering::Greater),
                },
            },
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(self_text), OwnedLiteral::LString(other_text)) => {
                    self_text.partial_cmp(other_text)
                }
                (
                    OwnedLiteral::LPositiveInteger(self_num),
                    OwnedLiteral::LPositiveInteger(other_num),
                ) => self_num.partial_cmp(other_num),
                (
                    OwnedLiteral::LNegativeInteger(self_num),
                    OwnedLiteral::LNegativeInteger(other_num),
                ) => self_num.partial_cmp(other_num),
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LFloat(other_num)) => {
                    self_num.partial_cmp(other_num)
                }
                (OwnedLiteral::LPositiveInteger(self_num), OwnedLiteral::LString(other_text)) => {
                    self_num.to_string().partial_cmp(other_text)
                }
                (OwnedLiteral::LString(self_text), OwnedLiteral::LPositiveInteger(other_num)) => {
                    self_text.partial_cmp(&other_num.to_string())
                }
                (OwnedLiteral::LNegativeInteger(self_num), OwnedLiteral::LString(other_text)) => {
                    self_num.to_string().partial_cmp(other_text)
                }
                (OwnedLiteral::LString(self_text), OwnedLiteral::LNegativeInteger(other_num)) => {
                    self_text.partial_cmp(&other_num.to_string())
                }
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LString(other_text)) => {
                    self_num.to_string().partial_cmp(other_text)
                }
                (OwnedLiteral::LString(self_text), OwnedLiteral::LFloat(other_num)) => {
                    self_text.partial_cmp(&other_num.to_string())
                }
                (OwnedLiteral::LPositiveInteger(self_num), OwnedLiteral::LFloat(other_num)) => {
                    (*self_num as f64).partial_cmp(other_num)
                }
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LPositiveInteger(other_num)) => {
                    self_num.partial_cmp(&(*other_num as f64))
                }
                (OwnedLiteral::LNegativeInteger(self_num), OwnedLiteral::LFloat(other_num)) => {
                    (*self_num as f64).partial_cmp(other_num)
                }
                (OwnedLiteral::LFloat(self_num), OwnedLiteral::LNegativeInteger(other_num)) => {
                    self_num.partial_cmp(&(*other_num as f64))
                }
                (
                    OwnedLiteral::LPositiveInteger(self_num),
                    OwnedLiteral::LNegativeInteger(other_num),
                ) => {
                    if *self_num < std::i64::MAX as u64 {
                        (*self_num as i64).partial_cmp(other_num)
                    } else {
                        Some(Ordering::Greater)
                    }
                }
                (
                    OwnedLiteral::LNegativeInteger(self_num),
                    OwnedLiteral::LPositiveInteger(other_num),
                ) => {
                    if *other_num < std::i64::MAX as u64 {
                        self_num.partial_cmp(&(*other_num as i64))
                    } else {
                        Some(Ordering::Less)
                    }
                }
            },
        }
    }

    fn math_add<'a>(&self, other: &dyn ContextElement) -> Option<IceResult<'a>> {
        // If its an OwnedLiteral then add them directly, otherwise
        // defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => other.math_add(self),
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(_), _) | (_, OwnedLiteral::LString(_)) => None,
                (_, _) => (std::convert::Into::<MathNumber>::into(self)
                    + std::convert::Into::<MathNumber>::into(other_literal))
                .map(IceResult::from_owned),
            },
        }
    }

    fn math_subtract<'a>(&self, other: &dyn ContextElement) -> Option<IceResult<'a>> {
        // If its an OwnedLiteral then subtract them directly,
        // otherwise defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => other.math_subtract(self),
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(_), _) | (_, OwnedLiteral::LString(_)) => None,
                (_, _) => (std::convert::Into::<MathNumber>::into(self)
                    - std::convert::Into::<MathNumber>::into(other_literal))
                .map(IceResult::from_owned),
            },
        }
    }

    fn math_multiply<'a>(&self, other: &dyn ContextElement) -> Option<IceResult<'a>> {
        // If its an OwnedLiteral then multiply them directly,
        // otherwise defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => other.math_multiply(self),
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(_), _) | (_, OwnedLiteral::LString(_)) => None,
                (_, _) => (std::convert::Into::<MathNumber>::into(self)
                    * std::convert::Into::<MathNumber>::into(other_literal))
                .map(IceResult::from_owned),
            },
        }
    }

    fn math_divide<'a>(&self, other: &dyn ContextElement) -> Option<IceResult<'a>> {
        // If its an OwnedLiteral then divide them directly, otherwise
        // defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => other.math_divide(self),
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(_), _) | (_, OwnedLiteral::LString(_)) => None,
                (_, _) => (std::convert::Into::<MathNumber>::into(self)
                    / std::convert::Into::<MathNumber>::into(other_literal))
                .map(IceResult::from_owned),
            },
        }
    }

    fn math_modulus<'a>(&self, other: &dyn ContextElement) -> Option<IceResult<'a>> {
        // If its an OwnedLiteral then modulus them directly,
        // otherwise defer to the other type's implementation of
        // CompareContextElement since the end user could add any
        // type.
        match other.to_any().downcast_ref::<Self>() {
            None => other.math_modulus(self),
            Some(other_literal) => match (self, other_literal) {
                (OwnedLiteral::LString(_), _) | (_, OwnedLiteral::LString(_)) => None,
                (_, _) => (std::convert::Into::<MathNumber>::into(self)
                    % std::convert::Into::<MathNumber>::into(other_literal))
                .map(IceResult::from_owned),
            },
        }
    }

    fn math_abs<'a>(&self) -> Option<IceResult<'a>> {
        std::convert::Into::<MathNumber>::into(self)
            .math_abs()
            .map(IceResult::from_owned)
    }

    fn math_floor<'a>(&self) -> Option<IceResult<'a>> {
        std::convert::Into::<MathNumber>::into(self)
            .math_floor()
            .map(IceResult::from_owned)
    }

    fn math_ceil<'a>(&self) -> Option<IceResult<'a>> {
        std::convert::Into::<MathNumber>::into(self)
            .math_ceil()
            .map(IceResult::from_owned)
    }
}