/// A definition path.
#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
pub struct DefinitionPath(pub String);

impl std::borrow::Borrow<str> for DefinitionPath {
    fn borrow(&self) -> &str {
        &self.0
    }
}

impl std::ops::Deref for DefinitionPath {
    type Target = str;

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

impl std::fmt::Display for DefinitionPath {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        self.0.fmt(f)
    }
}

/// An integer format. This corresponds to the `"format"` property of an `"integer"` schema type.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum IntegerFormat {
    Int32,
    Int64,
}

/// The value of an `x-kubernetes-list-type` annotation on a property.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Default, PartialOrd, Ord)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
pub enum KubernetesListType {
    #[default]
    #[cfg_attr(feature = "serde", serde(rename = "atomic"))]
    Atomic,

    #[cfg_attr(feature = "serde", serde(rename = "map"))]
    Map,

    #[cfg_attr(feature = "serde", serde(rename = "set"))]
    Set,
}

/// The value of an `x-kubernetes-map-type` annotation on a property.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Default, PartialOrd, Ord)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
pub enum KubernetesMapType {
    #[cfg_attr(feature = "serde", serde(rename = "atomic"))]
    Atomic,

    #[default]
    #[cfg_attr(feature = "serde", serde(rename = "granular"))]
    Granular,
}

#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum MergeType {
    Default,

    List {
        strategy: KubernetesListType,
        keys: Vec<String>,
        item_merge_type: Box<MergeType>,
    },

    Map {
        strategy: KubernetesMapType,
        value_merge_type: Box<MergeType>,
    },
}

/// A number format. This corresponds to the `"format"` property of a `"number"` schema type.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum NumberFormat {
    Double,
}

/// The name of a property of a schema type with a `"properties"` map.
#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
pub struct PropertyName(pub String);

impl std::borrow::Borrow<str> for PropertyName {
    fn borrow(&self) -> &str {
        &self.0
    }
}

impl std::ops::Deref for PropertyName {
    type Target = str;

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

impl std::fmt::Display for PropertyName {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        self.0.fmt(f)
    }
}

/// The path specified by a `"$ref"` property.
#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub struct RefPath {
    pub path: String,
    pub can_be_default: Option<bool>,
}

#[cfg(feature = "serde")]
impl<'de> serde::Deserialize<'de> for RefPath {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: serde::Deserializer<'de> {
        let path: String = serde::Deserialize::deserialize(deserializer)?;
        let mut parts = path.split('/');

        if parts.next() != Some("#") {
            return Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(&path), &"path like `#/definitions/$definitionName`"));
        }

        if parts.next() != Some("definitions") {
            return Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(&path), &"path like `#/definitions/$definitionName`"));
        }

        let ref_path = parts.next().ok_or_else(|| serde::de::Error::invalid_value(serde::de::Unexpected::Str(&path), &"path like `#/definitions/$definitionName`"))?;

        if parts.next().is_some() {
            return Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(&path), &"path like `#/definitions/$definitionName`"));
        }

        Ok(RefPath {
            path: ref_path.to_string(),
            can_be_default: None,
        })
    }
}

impl RefPath {
    pub(crate) fn references_scope(&self, map_namespace: &impl crate::MapNamespace) -> bool {
        let path_parts: Vec<_> = self.path.split('.').collect();
        map_namespace.map_namespace(&path_parts[..(path_parts.len() - 1)]).is_none()
    }
}

/// The schema of a definition or operation parameter.
#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub struct Schema {
    pub description: Option<String>,
    pub kind: SchemaKind,
    pub kubernetes_group_kind_versions: Vec<super::KubernetesGroupKindVersion>,

    pub merge_type: MergeType,

    /// Used to store the definition path of the corresponding list type, if any.
    pub list_kind: Option<String>,

    /// Used to enable or disable the auto-generated impl of `k8s_openapi::DeepMerge` on the generated type.
    pub impl_deep_merge: bool,
}

#[cfg(feature = "serde")]
#[allow(clippy::use_self)]
impl<'de> serde::Deserialize<'de> for Schema {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: serde::Deserializer<'de> {
        #[derive(Debug, serde::Deserialize)]
        struct InnerSchema {
            #[serde(rename = "additionalProperties")]
            additional_properties: Option<Box<Schema>>,

            description: Option<String>,

            format: Option<String>,

            items: Option<Box<Schema>>,

            #[serde(default, rename = "x-kubernetes-group-version-kind")]
            kubernetes_group_kind_versions: Vec<super::KubernetesGroupKindVersion>,

            #[serde(default, rename = "x-kubernetes-list-map-keys")]
            kubernetes_list_map_keys: Vec<String>,

            #[serde(default, rename = "x-kubernetes-list-type")]
            kubernetes_list_type: KubernetesListType,

            #[serde(default, rename = "x-kubernetes-map-type")]
            kubernetes_map_type: KubernetesMapType,

            #[serde(default, rename = "x-kubernetes-patch-merge-key")]
            kubernetes_patch_merge_key: Option<String>,

            /// Comma-separated list of strategy tags.
            /// Ref: https://github.com/kubernetes/community/blob/master/contributors/devel/sig-api-machinery/strategic-merge-patch.md
            #[serde(default, rename = "x-kubernetes-patch-strategy")]
            kubernetes_patch_strategy: String,

            properties: Option<std::collections::BTreeMap<PropertyName, Schema>>,

            #[serde(rename = "$ref")]
            ref_path: Option<RefPath>,

            #[serde(default)]
            required: Vec<PropertyName>,

            #[serde(rename = "type")]
            ty: Option<String>,
        }

        let mut value: InnerSchema = serde::Deserialize::deserialize(deserializer)?;

        let kind =
            if let Some(ref_path) = value.ref_path {
                SchemaKind::Ref(ref_path)
            }
            else if let Some(properties) = value.properties.take() {
                if value.ty.as_deref() != Some("object") {
                    return Err(serde::de::Error::custom(format!("schema has properties but not type=object {value:?}")));
                }

                let required: std::collections::BTreeSet<_> = value.required.into_iter().collect();
                SchemaKind::Properties(properties.into_iter().map(|(name, schema)| {
                    let required = required.contains(&name);
                    (name, (schema, required))
                }).collect())
            }
            else if let Some(ty) = value.ty {
                SchemaKind::Ty(Type::parse::<D>(
                    &ty,
                    value.additional_properties,
                    value.format.as_deref(),
                    value.items,
                )?)
            }
            else {
                SchemaKind::Ty(Type::Any)
            };

        if let Some(key) = value.kubernetes_patch_merge_key {
            value.kubernetes_list_map_keys = vec![key];
        }
        if value.kubernetes_patch_strategy.split(',').any(|x| x == "merge") {
            value.kubernetes_list_type =
                if value.kubernetes_list_map_keys.is_empty() {
                    KubernetesListType::Set
                }
                else {
                    KubernetesListType::Map
                };
        }

        let merge_type = match &kind {
            SchemaKind::Ty(Type::Array { items }) => MergeType::List {
                strategy: value.kubernetes_list_type,
                keys: value.kubernetes_list_map_keys,
                item_merge_type: Box::new(items.merge_type.clone()),
            },

            SchemaKind::Ty(Type::Object { additional_properties }) => MergeType::Map {
                strategy: value.kubernetes_map_type,
                value_merge_type: Box::new(additional_properties.merge_type.clone()),
            },

            _ => MergeType::Default,
        };

        Ok(Schema {
            description: value.description,
            kind,
            kubernetes_group_kind_versions: value.kubernetes_group_kind_versions,
            list_kind: None,
            merge_type,
            impl_deep_merge: true,
        })
    }
}

/// The kind of a [`Schema`]
#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum SchemaKind {
    Properties(std::collections::BTreeMap<PropertyName, (Schema, bool)>),
    Ref(RefPath),
    Ty(Type),
}

/// A string format. This corresponds to the `"format"` property of an `"string"` schema type.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum StringFormat {
    Byte,
    DateTime,
}

/// A type definition.
#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum Type {
    Any,
    Array { items: Box<Schema> },
    Boolean,
    Integer { format: IntegerFormat },
    Number { format: NumberFormat },
    Object { additional_properties: Box<Schema> },
    String { format: Option<StringFormat> },

    // Special type for the `subresources` field of custom resources.
    CustomResourceSubresources(String),

    // Special types that need alterative codegen
    IntOrString,
    JsonSchemaPropsOr(&'static str, JsonSchemaPropsOr),

    Patch,
    WatchEvent(RefPath),

    // Special type for lists
    ListDef { metadata: Box<SchemaKind> }, // The definition of the List type
    ListRef { items: Box<SchemaKind> }, // A reference to a specialization of the List type for a particular resource type, eg List<Pod> for PodList
}

#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum JsonSchemaPropsOr {
    Array,
    Bool,
    StringArray,
}

impl Type {
    #[cfg(feature = "serde")]
    pub(crate) fn parse<'de, D>(
        ty: &str,
        additional_properties: Option<Box<Schema>>,
        format: Option<&str>,
        items: Option<Box<Schema>>,
    ) -> Result<Self, D::Error> where D: serde::Deserializer<'de> {
        match ty {
            "array" => Ok(Type::Array {
                items: items.ok_or_else(|| serde::de::Error::missing_field("items"))?,
            }),

            "boolean" => Ok(Type::Boolean),

            "integer" => {
                let format = match format {
                    Some("int32") => IntegerFormat::Int32,
                    Some("int64") | None => IntegerFormat::Int64,
                    Some(format) => return Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(format), &"one of int32, int64")),
                };
                Ok(Type::Integer { format })
            },

            "number" => {
                let format = format.ok_or_else(|| serde::de::Error::missing_field("format"))?;
                let format = match format {
                    "double" => NumberFormat::Double,
                    format => return Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(format), &"one of double")),
                };
                Ok(Type::Number { format })
            },

            "object" => match additional_properties {
                Some(additional_properties) => Ok(Type::Object { additional_properties }),
                None => Ok(Type::Any),
            },

            "string" => {
                let format = match format {
                    Some("byte") => Some(StringFormat::Byte),
                    Some("date-time") => Some(StringFormat::DateTime),
                    Some("int-or-string") => return Ok(Type::IntOrString),
                    Some(format) => return Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(format), &"one of byte, date-time, int-or-string")),
                    None => None,
                };
                Ok(Type::String { format })
            },

            s => Err(serde::de::Error::invalid_value(serde::de::Unexpected::Str(s), &"one of array, boolean, integer, number, object, string")),
        }
    }
}