use crate::spec::{AlternativeAction, AlternativeBuild, AlternativeBuildChild, AlternativeChild, AlternativeTest, BooleanChildToBuild, BuildSpec, EnumBuildSpec, EnumRule, EnumRuleChild, EnumRuleChildKind, EnumRuleNodeChild, LeafEnumBuildSpec, LeafEnumRule, LeafStructBuildSpec, LeafStructMember, LeafStructMemberKind, MemberChild, MemberChildToBuild, NameAndKind, NodeChildToBuild, PolymorphicBuildAlternative, PolymorphicBuildBuildSpec, PolymorphicEnumBuildSpec, PolymorphicEnumMember, PolymorphicEnumRule, PolymorphicTypeBuildSpec, ProductionBuildSpec, ProductionKind, ProductionStringFrom, SkipChild, StructBuildSpec, StructChildSpec, VecChild, VecChildToBuild, VecNodeChildToBuild};
use convert_case::{Case, Casing};
use yaml_rust2::{Yaml, YamlLoader};

fn get_as_bool(yaml: &Yaml) -> bool {
    yaml.as_bool().unwrap_or_else(|| false)
}

fn unwrap_single_member_hash(hash: &Yaml) -> (String, &Yaml) {
    let as_hash = hash.as_hash().unwrap();
    if as_hash.is_empty() {
        panic!("empty hash");
    } else if as_hash.len() > 1 {
        panic!("hash contains more than one key");
    }
    let (member_key, member_value) = as_hash.iter().collect::<Vec<(&Yaml, &Yaml)>>()[0];
    let key_as_string = member_key.as_str().unwrap().to_string();
    (key_as_string, member_value)
}

fn deserialize_polymorphic_enum_build_spec(name: &str, build_spec: &Yaml) -> PolymorphicEnumBuildSpec {
    let return_type = build_spec["return_type"].as_str().unwrap();
    let rules = build_spec["rules"]
        .as_vec()
        .unwrap()
        .iter()
        .map(|rule_yaml| {
            let (rule_name, props) = unwrap_single_member_hash(rule_yaml);
            if props["wrap"].is_hash() {
                PolymorphicEnumRule::Wrap(NameAndKind::new(
                    &rule_name,
                    props["wrap"]["enum_variant"].as_str().unwrap()
                ))
            } else if props["return_build"].is_hash() {
                PolymorphicEnumRule::ReturnBuild(NameAndKind::new(
                    &rule_name,
                    props["return_build"]["kind"].as_str().unwrap()
                ))
            } else {
                panic!()
            }
        })
        .map(Box::new)
        .collect::<Vec<_>>();
    PolymorphicEnumBuildSpec::new(name, return_type, rules)
}

fn deserialize_polymorphic_action(action_yaml: &Yaml) -> AlternativeAction {
    if action_yaml["return_build"].is_hash() {
        let kind = action_yaml["return_build"]["kind"].as_str().unwrap();
        AlternativeAction::ReturnBuild(kind.to_string())
    } else if action_yaml["build"].is_hash() {
        let build_children = action_yaml["build"]["children"]
            .as_vec()
            .unwrap()
            .iter()
            .map(|child_yaml| {
                let (child_name, child_props) = unwrap_single_member_hash(child_yaml);
                if get_as_bool(&child_props["skip"]) {
                    AlternativeChild::Skip
                } else {
                    let kind = child_props["kind"].as_str().unwrap();
                    let rule = child_props["rule"].as_str().unwrap();
                    AlternativeChild::Build(AlternativeBuildChild::new(&child_name, kind, rule))
                }
            })
            .map(Box::new)
            .collect();
        let enum_variant = action_yaml["build"]["enum_variant"].as_str().unwrap();
        let build = AlternativeBuild::new(enum_variant, build_children);
        AlternativeAction::Build(build)
    } else {
        panic!("return_build or build is required for an alternative")
    }
}

fn deserialize_polymorphic_build_build_spec(
    name: &str,
    polymorphic_build_yaml: &Yaml
) -> PolymorphicBuildBuildSpec {
    let return_type = polymorphic_build_yaml["return_type"].as_str().unwrap();
    let alternatives = polymorphic_build_yaml["alternatives"]
        .as_vec()
        .unwrap()
        .iter()
        .map(|alternative_yaml| {
            let number_of_pairs = alternative_yaml["test"]["number_of_pairs"].as_i64().unwrap();
            let action = deserialize_polymorphic_action(&alternative_yaml["action"]);
            PolymorphicBuildAlternative::new(
                AlternativeTest::NumberOfPairs(number_of_pairs),
                action
            )
        })
        .map(Box::new)
        .collect();
    PolymorphicBuildBuildSpec::new(name, return_type, alternatives)
}

fn deserialize_polymorphic_enum_members(
    enum_members_yaml: &Yaml,
) -> Vec<Box<PolymorphicEnumMember>> {
    enum_members_yaml
        .as_vec()
        .unwrap()
        .iter()
        .map(|enum_member_yaml| {
            let (member_name, member_hash) = unwrap_single_member_hash(enum_member_yaml);
            let inner_kind = member_hash["inner"]["kind"].as_str().unwrap();
            PolymorphicEnumMember::new(&member_name, inner_kind)
        })
        .map(Box::new)
        .collect()
}

fn deserialize_polymorphic_spec(name: &str, spec_props: &Yaml) -> PolymorphicTypeBuildSpec {
    let enum_members = deserialize_polymorphic_enum_members(&spec_props["enum_members"]);
    let build_kind = spec_props["build"]["kind"].as_str().unwrap();
    PolymorphicTypeBuildSpec::new(name, enum_members, build_kind)
}

fn deserialize_production_spec(rule: &str, production_yaml: &Yaml) -> ProductionBuildSpec {
    let kind = if production_yaml["kind"].is_hash() {
        let node = production_yaml["kind"]["node"].as_str().unwrap();
        ProductionKind::Node(node.to_string())
    } else { 
        match production_yaml["kind"].as_str().unwrap() {
            "int" => ProductionKind::Int,
            "long" => ProductionKind::Long,
            "double" => ProductionKind::Double,
            "boolean" => ProductionKind::Boolean,
            "string" => {
                let from = match production_yaml["from"].as_str().unwrap() {
                    "string_inner" => ProductionStringFrom::StringInner,
                    "whole_pair" => ProductionStringFrom::WholePair,
                    _ => panic!(
                        "invalid from: {}",
                        production_yaml["from"].as_str().unwrap()
                    ),
                };
                ProductionKind::String(from)
            }
            _ => panic!(
                "invalid kind: {}",
                production_yaml["kind"].as_str().unwrap()
            ),
        }
    };
    ProductionBuildSpec::new(rule, kind)
}

fn deserialize_leaf_enum_rule(rule_yaml: &Yaml) -> Box<LeafEnumRule> {
    Box::new(LeafEnumRule::new(rule_yaml.as_str().unwrap()))
}

fn deserialize_leaf_enum_rules(rules_yaml: &Yaml) -> Vec<Box<LeafEnumRule>> {
    rules_yaml
        .as_vec()
        .unwrap()
        .iter()
        .map(|rule_yaml| deserialize_leaf_enum_rule(rule_yaml))
        .collect()
}

fn deserialize_enum_rule_custom_child(rule_props: &Yaml) -> Option<Box<EnumRuleChild>> {
    if !rule_props["child"].as_bool().unwrap_or(true) {
        None
    } else {
        let kind = match rule_props["kind"].as_str().unwrap() {
            "int" => EnumRuleChildKind::Int,
            "long" => EnumRuleChildKind::Long,
            "double" => EnumRuleChildKind::Double,
            "usize" => EnumRuleChildKind::USize,
            "string" => EnumRuleChildKind::String,
            "boolean" => EnumRuleChildKind::Boolean,
            _ => panic!(
                "unsupported enum rule kind: {}",
                rule_props["kind"].as_str().unwrap()
            ),
        };
        Some(Box::new(EnumRuleChild::new(Box::new(kind))))
    }
}

fn deserialize_enum_rule_node_child(rule: &str) -> Box<EnumRuleChild> {
    Box::new(EnumRuleChild::new(Box::new(EnumRuleChildKind::Node(
        EnumRuleNodeChild::new(rule),
    ))))
}

fn deserialize_enum_rule(rule_yaml: &Yaml) -> Box<EnumRule> {
    if rule_yaml.is_hash() {
        let (rule, rule_props) = unwrap_single_member_hash(rule_yaml);
        Box::new(EnumRule::new(
            &rule,
            deserialize_enum_rule_custom_child(rule_props),
        ))
    } else {
        let rule_as_str = rule_yaml.as_str().unwrap();
        Box::new(EnumRule::new(
            rule_as_str,
            Some(deserialize_enum_rule_node_child(rule_as_str)),
        ))
    }
}

fn deserialize_enum_rules(rules_yaml: &Yaml) -> Vec<Box<EnumRule>> {
    rules_yaml
        .as_vec()
        .unwrap()
        .iter()
        .map(|rule_yaml| deserialize_enum_rule(rule_yaml))
        .collect()
}

fn deserialize_leaf_struct_member(name: &str, props: &Yaml) -> Box<LeafStructMember> {
    let kind = props["kind"].as_str().unwrap();
    if kind == "string" {
        Box::new(LeafStructMember::new(name, LeafStructMemberKind::String))
    } else {
        panic!("invalid member kind: {}", kind);
    }
}

fn deserialize_leaf_struct_members(members_yaml: &Yaml) -> Vec<Box<LeafStructMember>> {
    members_yaml
        .as_vec()
        .unwrap()
        .iter()
        .map(|member| {
            let (member_name, member_props) = unwrap_single_member_hash(member);
            deserialize_leaf_struct_member(&member_name, member_props)
        })
        .collect()
}

fn deserialize_member_node_to_build(
    rule: &str,
    build_props: &Yaml,
    optional: bool,
) -> Box<MemberChildToBuild> {
    let or_else = build_props["or_else"]
        .as_str()
        .or_else(|| {
            if get_as_bool(&build_props["or_else_default"]) {
                Some("default")
            } else {
                None
            }
        })
        .map(ToString::to_string);

    Box::new(MemberChildToBuild::Node(NodeChildToBuild::new(
        rule, or_else, optional,
    )))
}

fn deserialize_member_boolean_to_build(name: &str) -> Box<MemberChildToBuild> {
    Box::new(MemberChildToBuild::Boolean(BooleanChildToBuild::new(name)))
}

fn deserialize_member_child_to_build(
    name: &str,
    rule: &str,
    props: &Yaml,
    optional: bool,
) -> Box<MemberChildToBuild> {
    if props["build"].is_hash() {
        let build_props = &props["build"];
        let kind = build_props["kind"].as_str().or(Some("node")).unwrap();
        if kind == "node" {
            deserialize_member_node_to_build(rule, build_props, optional)
        } else if kind == "boolean" {
            deserialize_member_boolean_to_build(name)
        } else {
            panic!("unsupported kind: {}", kind)
        }
    } else {
        let optional = get_as_bool(&props["optional"]);
        Box::new(MemberChildToBuild::Node(NodeChildToBuild::new(
            rule, None, optional,
        )))
    }
}

fn deserialize_member_child(
    name: &str,
    rule: &str,
    optional: bool,
    props: &Yaml,
) -> Box<StructChildSpec> {
    Box::new(StructChildSpec::MemberChild(MemberChild::new(
        name,
        rule,
        deserialize_member_child_to_build(name, rule, props, optional),
    )))
}

fn deserialize_vec_node_child(name: &str, props: &Yaml) -> Box<StructChildSpec> {
    let rule = props["rule"].as_str().unwrap();
    Box::new(StructChildSpec::VecChild(VecChild::new(
        name,
        rule,
        Box::new(VecChildToBuild::Node(VecNodeChildToBuild::new(rule))),
    )))
}

fn deserialize_vec_string_child(name: &str, props: &Yaml) -> Box<StructChildSpec> {
    let rule = props["rule"].as_str().unwrap();
    Box::new(StructChildSpec::VecChild(VecChild::new(
        name,
        rule,
        Box::new(VecChildToBuild::String),
    )))
}

fn deserialize_vec_child(name: &str, props: &Yaml) -> Box<StructChildSpec> {
    let kind = props["kind"].as_str().or_else(|| Some("node")).unwrap();
    if kind == "node" {
        deserialize_vec_node_child(name, props)
    } else if kind == "string" {
        deserialize_vec_string_child(name, props)
    } else {
        panic!("invalid kind: {}", kind);
    }
}

fn deserialize_skip_child(name: &str, rule: &str) -> Box<StructChildSpec> {
    Box::new(StructChildSpec::SkipChild(SkipChild::new(name, rule)))
}

fn deserialize_struct_hash_child(child: &Yaml) -> Box<StructChildSpec> {
    let (name, props) = unwrap_single_member_hash(child);

    let rule = props["rule"]
        .as_str()
        .map(|s| s.to_string())
        .unwrap_or(name.to_case(Case::Pascal));

    if get_as_bool(&props["skip"]) {
        deserialize_skip_child(&name, &rule)
    } else {
        if get_as_bool(&props["vec"]) {
            deserialize_vec_child(&name, props)
        } else {
            let optional = get_as_bool(&props["optional"]);
            deserialize_member_child(&name, &rule, optional, props)
        }
    }
}

fn deserialize_struct_string_child(child: &Yaml) -> Box<StructChildSpec> {
    let child_as_str = child.as_str().unwrap();
    let child_name_pascal = child_as_str.to_case(Case::Pascal);
    Box::new(StructChildSpec::MemberChild(MemberChild::new(
        child_as_str,
        &child_name_pascal,
        Box::new(MemberChildToBuild::Node(NodeChildToBuild::new(
            &child_name_pascal,
            None,
            false,
        ))),
    )))
}

fn deserialize_struct_children(children: &Yaml) -> Vec<Box<StructChildSpec>> {
    children
        .as_vec()
        .unwrap()
        .iter()
        .map(|child_spec| {
            if child_spec.is_hash() {
                deserialize_struct_hash_child(child_spec)
            } else {
                deserialize_struct_string_child(child_spec)
            }
        })
        .collect()
}

fn deserialize_build_spec(build_spec_name: &str, build_spec: &Yaml) -> BuildSpec {
    if build_spec["children"].is_array() {
        let children = deserialize_struct_children(&build_spec["children"]);
        BuildSpec::Struct(StructBuildSpec::new(build_spec_name, children))
    } else if build_spec["members"].is_array() {
        let members = deserialize_leaf_struct_members(&build_spec["members"]);
        BuildSpec::LeafStruct(LeafStructBuildSpec::new(build_spec_name, members))
    } else if build_spec["rules"].is_array() {
        let rules = deserialize_enum_rules(&build_spec["rules"]);
        BuildSpec::Enum(EnumBuildSpec::new(build_spec_name, rules))
    } else if build_spec["leaf_rules"].is_array() {
        let leaf_rules = deserialize_leaf_enum_rules(&build_spec["leaf_rules"]);
        BuildSpec::LeafEnum(LeafEnumBuildSpec::new(build_spec_name, leaf_rules))
    } else if build_spec["produce"].is_hash() {
        BuildSpec::Production(deserialize_production_spec(
            build_spec_name,
            &build_spec["produce"],
        ))
    } else if build_spec["polymorphic_type"].is_hash() {
        BuildSpec::Polymorphic(deserialize_polymorphic_spec(
            build_spec_name,
            &build_spec["polymorphic_type"],
        ))
    } else if build_spec["polymorphic_build"].is_hash() {
        BuildSpec::PolymorphicBuild(deserialize_polymorphic_build_build_spec(
            build_spec_name,
            &build_spec["polymorphic_build"],
        ))
    } else if build_spec["polymorphic_enum"].is_hash() {
        BuildSpec::PolymorphicEnum(deserialize_polymorphic_enum_build_spec(
            build_spec_name,
            &build_spec["polymorphic_enum"],
        ))    
    } else {
        panic!(
            "Expected a node spec for either a struct, leaf_struct, enum, leaf_enum node type, production, polymorphic type, or polymorphic build type."
        );
    }
}

pub fn deserialize_yaml_spec(yaml: &str) -> Vec<BuildSpec> {
    let docs = YamlLoader::load_from_str(yaml).unwrap();
    let doc = &docs[0];

    doc.as_hash()
        .unwrap()
        .iter()
        .map(|(build_spec_name, build_spec)| {
            let name_as_str = build_spec_name.as_str().unwrap();
            deserialize_build_spec(name_as_str, build_spec)
        })
        .collect()
}