use std::borrow::Cow;
use std::collections::BTreeMap;

#[cfg(feature = "serde_json")]
use displaydoc::Display;
use thiserror::Error;

use crate::Nomo;

#[derive(Clone)]
pub enum NomoValue {
    String {
        value: Cow<'static, str>,
    },
    Array {
        value: Vec<NomoValue>,
    },
    Bool {
        value: bool,
    },
    Object {
        value: BTreeMap<String, NomoValue>,
    },
    Integer {
        value: u64,
    },
    SignedInteger {
        value: i64,
    },
    Float {
        value: f64,
    },
    Iterator {
        value: Box<dyn CloneIterator<Item = NomoValue>>,
    },
}

impl NomoValue {
    pub fn as_str(&self) -> Option<&str> {
        if let Self::String { value } = self {
            Some(value)
        } else {
            None
        }
    }

    pub fn as_array(&self) -> Option<&[NomoValue]> {
        if let Self::Array { value } = self {
            Some(value)
        } else {
            None
        }
    }

    pub fn as_bool(&self) -> Option<bool> {
        if let Self::Bool { value } = self {
            Some(*value)
        } else {
            None
        }
    }

    pub fn as_object(&self) -> Option<&BTreeMap<String, NomoValue>> {
        if let Self::Object { value } = self {
            Some(value)
        } else {
            None
        }
    }

    pub fn as_integer(&self) -> Option<u64> {
        if let Self::Integer { value } = self {
            Some(*value)
        } else {
            None
        }
    }

    pub fn as_float(&self) -> Option<f64> {
        if let Self::Float { value } = self {
            Some(*value)
        } else {
            None
        }
    }

    pub fn as_iterator(&self) -> Option<&dyn CloneIterator<Item = NomoValue>> {
        if let Self::Iterator { value } = self {
            Some(value)
        } else {
            None
        }
    }

    pub fn as_iterator_mut(&mut self) -> Option<&mut dyn CloneIterator<Item = NomoValue>> {
        if let Self::Iterator { value } = self {
            Some(value)
        } else {
            None
        }
    }

    pub(crate) fn try_add(&self, right_value: &NomoValue) -> Option<NomoValue> {
        match (self, right_value) {
            (NomoValue::Integer { value: lval }, NomoValue::Integer { value: rval }) => {
                Some(NomoValue::Integer {
                    value: *lval + *rval,
                })
            }
            (
                NomoValue::SignedInteger { value: lval },
                NomoValue::SignedInteger { value: rval },
            ) => Some(NomoValue::SignedInteger {
                value: *lval + *rval,
            }),
            (NomoValue::Integer { value: val }, NomoValue::SignedInteger { value: sval })
            | (NomoValue::SignedInteger { value: sval }, NomoValue::Integer { value: val }) => {
                Some(NomoValue::SignedInteger {
                    value: (i64::try_from(*val).ok()?) + *sval,
                })
            }
            (NomoValue::String { value: rstr }, NomoValue::String { value: lstr }) => {
                Some(NomoValue::String {
                    value: Cow::Owned(format!("{rstr}{lstr}")),
                })
            }
            (NomoValue::Array { value: lval }, NomoValue::Array { value: rval }) => {
                Some(NomoValue::Array {
                    value: Vec::from_iter(lval.iter().chain(rval.iter()).cloned()),
                })
            }
            _ => None,
        }
    }

    pub(crate) fn try_sub(&self, right_value: &NomoValue) -> Option<NomoValue> {
        macro_rules! op {
            ($left:expr, $right:expr) => {{ ($left) - ($right) }};
        }
        match (self, right_value) {
            (NomoValue::Integer { value: lval }, NomoValue::Integer { value: rval }) => {
                Some(NomoValue::Integer {
                    value: op!(*lval, *rval),
                })
            }
            (
                NomoValue::SignedInteger { value: lval },
                NomoValue::SignedInteger { value: rval },
            ) => Some(NomoValue::SignedInteger {
                value: op!(*lval, *rval),
            }),
            (NomoValue::Integer { value: val }, NomoValue::SignedInteger { value: sval })
            | (NomoValue::SignedInteger { value: sval }, NomoValue::Integer { value: val }) => {
                Some(NomoValue::SignedInteger {
                    value: op!(i64::try_from(*val).ok()?, *sval),
                })
            }
            _ => None,
        }
    }

    pub(crate) fn try_mul(&self, right_value: &NomoValue) -> Option<NomoValue> {
        macro_rules! op {
            ($left:expr, $right:expr) => {{ ($left) * ($right) }};
        }
        match (self, right_value) {
            (NomoValue::Integer { value: lval }, NomoValue::Integer { value: rval }) => {
                Some(NomoValue::Integer {
                    value: op!(*lval, *rval),
                })
            }
            (
                NomoValue::SignedInteger { value: lval },
                NomoValue::SignedInteger { value: rval },
            ) => Some(NomoValue::SignedInteger {
                value: op!(*lval, *rval),
            }),
            (NomoValue::Integer { value: val }, NomoValue::SignedInteger { value: sval })
            | (NomoValue::SignedInteger { value: sval }, NomoValue::Integer { value: val }) => {
                Some(NomoValue::SignedInteger {
                    value: op!(i64::try_from(*val).ok()?, *sval),
                })
            }
            _ => None,
        }
    }

    pub(crate) fn try_div(&self, right_value: &NomoValue) -> Option<NomoValue> {
        macro_rules! op {
            ($left:expr, $right:expr) => {{ ($left) / ($right) }};
        }
        match (self, right_value) {
            (NomoValue::Integer { value: lval }, NomoValue::Integer { value: rval }) => {
                Some(NomoValue::Integer {
                    value: op!(*lval, *rval),
                })
            }
            (
                NomoValue::SignedInteger { value: lval },
                NomoValue::SignedInteger { value: rval },
            ) => Some(NomoValue::SignedInteger {
                value: op!(*lval, *rval),
            }),
            (NomoValue::Integer { value: val }, NomoValue::SignedInteger { value: sval })
            | (NomoValue::SignedInteger { value: sval }, NomoValue::Integer { value: val }) => {
                Some(NomoValue::SignedInteger {
                    value: op!(i64::try_from(*val).ok()?, *sval),
                })
            }
            _ => None,
        }
    }

    pub(crate) fn try_and(&self, right_value: &NomoValue) -> Option<NomoValue> {
        match (self, right_value) {
            (NomoValue::Bool { value: lval }, NomoValue::Bool { value: rval }) => {
                Some(NomoValue::Bool {
                    value: *lval && *rval,
                })
            }
            _ => None,
        }
    }

    pub(crate) fn try_or(&self, right_value: &NomoValue) -> Option<NomoValue> {
        match (self, right_value) {
            (NomoValue::Bool { value: lval }, NomoValue::Bool { value: rval }) => {
                Some(NomoValue::Bool {
                    value: *lval || *rval,
                })
            }
            _ => None,
        }
    }

    pub(crate) fn try_to_string(&self) -> Option<String> {
        match self {
            NomoValue::String { value } => Some(value.to_string()),
            NomoValue::Array { .. } => None,
            NomoValue::Bool { value } => Some(value.to_string()),
            NomoValue::Object { .. } => None,
            NomoValue::Integer { value } => Some(value.to_string()),
            NomoValue::SignedInteger { value } => Some(value.to_string()),
            NomoValue::Float { value } => Some(value.to_string()),
            NomoValue::Iterator { .. } => None,
        }
    }
}

pub trait CloneIterator: Iterator<Item = NomoValue> {
    fn clone_box(&self) -> Box<dyn CloneIterator<Item = NomoValue>>;
}

impl<I> CloneIterator for I
where
    I: Iterator<Item = NomoValue> + Clone + 'static,
{
    fn clone_box(&self) -> Box<dyn CloneIterator<Item = NomoValue>> {
        Box::new(Clone::clone(self))
    }
}

impl Clone for Box<dyn CloneIterator> {
    fn clone(&self) -> Self {
        self.clone_box()
    }
}

impl std::fmt::Debug for NomoValue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::String { value } => f.debug_struct("String").field("value", value).finish(),
            Self::Array { value } => f.debug_struct("Array").field("value", value).finish(),
            Self::Bool { value } => f.debug_struct("Bool").field("value", value).finish(),
            Self::Object { value } => f.debug_struct("Object").field("value", value).finish(),
            Self::Integer { value } => f.debug_struct("Integer").field("value", value).finish(),
            Self::SignedInteger { value } => f
                .debug_struct("SignedInteger")
                .field("value", value)
                .finish(),
            Self::Float { value } => f.debug_struct("Float").field("value", value).finish(),
            Self::Iterator { value: _ } => f
                .debug_struct("Iterator")
                .field("value", &"Iterator")
                .finish(),
        }
    }
}

impl<R> From<&R> for NomoValue
where
    R: Into<NomoValue> + Clone,
{
    fn from(value: &R) -> Self {
        value.clone().into()
    }
}

impl From<String> for NomoValue {
    fn from(val: String) -> Self {
        NomoValue::String {
            value: Cow::Owned(val),
        }
    }
}

impl From<&'static str> for NomoValue {
    fn from(val: &'static str) -> Self {
        NomoValue::String {
            value: Cow::Borrowed(val),
        }
    }
}

impl<V> From<Vec<V>> for NomoValue
where
    V: Into<NomoValue>,
{
    fn from(val: Vec<V>) -> Self {
        NomoValue::Array {
            value: val.into_iter().map(Into::into).collect(),
        }
    }
}

impl<V> From<std::collections::VecDeque<V>> for NomoValue
where
    V: Into<NomoValue>,
{
    fn from(val: std::collections::VecDeque<V>) -> Self {
        NomoValue::Array {
            value: val.into_iter().map(Into::into).collect(),
        }
    }
}

impl<V> From<&[V]> for NomoValue
where
    V: Into<NomoValue> + Clone,
{
    fn from(value: &[V]) -> Self {
        NomoValue::Array {
            value: value.iter().cloned().map(Into::into).collect(),
        }
    }
}

impl<K, V> From<std::collections::HashMap<K, V>> for NomoValue
where
    K: Into<String>,
    V: Into<NomoValue>,
{
    fn from(val: std::collections::HashMap<K, V>) -> Self {
        NomoValue::Object {
            value: val.into_iter().map(|(k, v)| (k.into(), v.into())).collect(),
        }
    }
}

#[cfg(feature = "serde_json")]
#[derive(Debug, Error, Display)]
/// Could not transform value to [`NomoValue`]
pub struct NomoValueError;

#[cfg(feature = "serde_json")]
impl TryFrom<serde_json::Value> for NomoValue {
    type Error = NomoValueError;
    fn try_from(value: serde_json::Value) -> Result<Self, NomoValueError> {
        match value {
            serde_json::Value::Null => todo!(),
            serde_json::Value::Bool(value) => Ok(NomoValue::Bool { value }),
            serde_json::Value::Number(number) => {
                if let Some(value) = number.as_u64() {
                    return Ok(NomoValue::Integer { value });
                }

                if let Some(value) = number.as_f64() {
                    return Ok(NomoValue::Float { value });
                }

                if let Some(value) = number.as_i64() {
                    return Ok(NomoValue::SignedInteger { value });
                }

                Err(NomoValueError)
            }
            serde_json::Value::String(str) => Ok(NomoValue::String {
                value: Cow::Owned(str),
            }),
            serde_json::Value::Array(values) => Ok(NomoValue::Array {
                value: values
                    .into_iter()
                    .map(TryInto::try_into)
                    .collect::<Result<_, _>>()?,
            }),
            serde_json::Value::Object(_map) => todo!(),
        }
    }
}