// Copyright 2024 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::collections::HashMap;

use serde::de::{self, DeserializeSeed, EnumAccess, MapAccess, SeqAccess, VariantAccess, Visitor};
use serde::Deserialize;

use crate::error::{Error, Result};

#[derive(Debug)]
pub struct Deserializer<'s, 'o> {
    input: &'s str,
    objects: Option<&'o HashMap<&'s str, &'s str>>,
    top_level: bool,
    key: &'s str,
}

impl<'s, 'o, 'a> de::Deserializer<'s> for &'a mut Deserializer<'s, 'o> {
    type Error = Error;

    fn deserialize_any<V>(self, _visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        Err(Error::UnknownType)
    }

    fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        let s = self.consume_input();
        match s {
            "on" | "true" => visitor.visit_bool(true),
            "off" | "false" => visitor.visit_bool(false),
            _ => Err(Error::ExpectedBool),
        }
    }

    fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_i8(self.parse_signed()?)
    }

    fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_i16(self.parse_signed()?)
    }

    fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_i32(self.parse_signed()?)
    }

    fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_i64(self.parse_signed()?)
    }

    fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_u8(self.parse_unsigned()?)
    }

    fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_u16(self.parse_unsigned()?)
    }

    fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_u32(self.parse_unsigned()?)
    }

    fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_u64(self.parse_unsigned()?)
    }

    fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        let s = self.consume_input();
        visitor.visit_f32(s.parse().map_err(|_| Error::ExpectedFloat)?)
    }

    fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        let s = self.consume_input();
        visitor.visit_f64(s.parse().map_err(|_| Error::ExpectedFloat)?)
    }

    fn deserialize_char<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_str(visitor)
    }

    fn deserialize_str<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        if self.top_level {
            visitor.visit_borrowed_str(self.consume_all())
        } else {
            let id = self.consume_input();
            visitor.visit_borrowed_str(self.deref_id(id)?)
        }
    }

    fn deserialize_string<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_str(visitor)
    }

    fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_seq(visitor)
    }

    fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_bytes(visitor)
    }

    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        let id = self.consume_input();
        let s = self.deref_id(id)?;
        if id.starts_with("id_") && s.is_empty() {
            visitor.visit_none()
        } else {
            let mut sub_de = Deserializer { input: s, ..*self };
            visitor.visit_some(&mut sub_de)
        }
    }

    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        let s = self.consume_input();
        if s.is_empty() {
            visitor.visit_unit()
        } else {
            Err(Error::ExpectedUnit)
        }
    }

    fn deserialize_unit_struct<V>(self, _name: &'static str, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_unit(visitor)
    }

    fn deserialize_newtype_struct<V>(self, _name: &'static str, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_newtype_struct(self)
    }

    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_nested(|de| visitor.visit_seq(CommaSeparated::new(de)))
    }

    fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_seq(visitor)
    }

    fn deserialize_tuple_struct<V>(
        self,
        _name: &'static str,
        _len: usize,
        visitor: V,
    ) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_seq(visitor)
    }

    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_nested(|de| visitor.visit_map(CommaSeparated::new(de)))
    }

    fn deserialize_struct<V>(
        self,
        _name: &'static str,
        _fields: &'static [&'static str],
        visitor: V,
    ) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_map(visitor)
    }

    fn deserialize_enum<V>(
        self,
        _name: &'static str,
        _variants: &'static [&'static str],
        visitor: V,
    ) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        self.deserialize_nested(|de| visitor.visit_enum(Enum::new(de)))
    }

    fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_borrowed_str(self.consume_input())
    }

    fn deserialize_ignored_any<V>(self, _visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        Err(Error::Ignored(self.key.to_owned()))
    }
}

impl<'s, 'o> Deserializer<'s, 'o> {
    pub fn from_args(input: &'s str, objects: &'o HashMap<&'s str, &'s str>) -> Self {
        Deserializer {
            input,
            objects: Some(objects),
            top_level: true,
            key: "",
        }
    }

    pub fn from_arg(input: &'s str) -> Self {
        Deserializer {
            input,
            objects: None,
            top_level: true,
            key: "",
        }
    }

    fn end(&self) -> Result<()> {
        if self.input.is_empty() {
            Ok(())
        } else {
            Err(Error::Trailing(self.input.to_owned()))
        }
    }

    fn deserialize_nested<F, V>(&mut self, f: F) -> Result<V>
    where
        F: FnOnce(&mut Self) -> Result<V>,
    {
        let mut sub_de;
        let de = if !self.top_level {
            let id = self.consume_input();
            let sub_input = self.deref_id(id)?;
            sub_de = Deserializer {
                input: sub_input,
                ..*self
            };
            &mut sub_de
        } else {
            self.top_level = false;
            self
        };
        let val = f(de)?;
        de.end()?;
        Ok(val)
    }

    fn consume_input_until(&mut self, end: char) -> Option<&'s str> {
        let len = self.input.find(end)?;
        let s = &self.input[..len];
        self.input = &self.input[len + end.len_utf8()..];
        Some(s)
    }

    fn consume_all(&mut self) -> &'s str {
        let s = self.input;
        self.input = "";
        s
    }

    fn consume_input(&mut self) -> &'s str {
        match self.consume_input_until(',') {
            Some(s) => s,
            None => self.consume_all(),
        }
    }

    fn deref_id(&self, id: &'s str) -> Result<&'s str> {
        if id.starts_with("id_") {
            if let Some(s) = self.objects.and_then(|objects| objects.get(id)) {
                Ok(s)
            } else {
                Err(Error::IdNotFound(id.to_owned()))
            }
        } else {
            Ok(id)
        }
    }

    fn parse_unsigned<T>(&mut self) -> Result<T>
    where
        T: TryFrom<u64>,
    {
        let s = self.consume_input();
        let (num, shift) = if let Some((num, "")) = s.split_once(['k', 'K']) {
            (num, 10)
        } else if let Some((num, "")) = s.split_once(['m', 'M']) {
            (num, 20)
        } else if let Some((num, "")) = s.split_once(['g', 'G']) {
            (num, 30)
        } else if let Some((num, "")) = s.split_once(['t', 'T']) {
            (num, 40)
        } else {
            (s, 0)
        };
        let n = if let Some(num_h) = num.strip_prefix("0x") {
            u64::from_str_radix(num_h, 16)
        } else if let Some(num_o) = num.strip_prefix("0o") {
            u64::from_str_radix(num_o, 8)
        } else if let Some(num_b) = num.strip_prefix("0b") {
            u64::from_str_radix(num_b, 2)
        } else {
            num.parse::<u64>()
        }
        .map_err(|_| Error::ExpectedInteger)?;

        let shifted_n = n.checked_shl(shift).ok_or(Error::Overflow)?;

        T::try_from(shifted_n).map_err(|_| Error::Overflow)
    }

    fn parse_signed<T>(&mut self) -> Result<T>
    where
        T: TryFrom<i64>,
    {
        let i = if self.input.starts_with('-') {
            let s = self.consume_input();
            s.parse().map_err(|_| Error::ExpectedInteger)
        } else {
            let n = self.parse_unsigned::<u64>()?;
            i64::try_from(n).map_err(|_| Error::Overflow)
        }?;
        T::try_from(i).map_err(|_| Error::Overflow)
    }
}

pub fn from_args<'s, 'o, T>(s: &'s str, objects: &'o HashMap<&'s str, &'s str>) -> Result<T>
where
    T: Deserialize<'s>,
{
    let mut deserializer = Deserializer::from_args(s, objects);
    let value = T::deserialize(&mut deserializer)?;
    deserializer.end()?;
    Ok(value)
}

pub fn from_arg<'s, T>(s: &'s str) -> Result<T>
where
    T: Deserialize<'s>,
{
    let mut deserializer = Deserializer::from_arg(s);
    let value = T::deserialize(&mut deserializer)?;
    deserializer.end()?;
    Ok(value)
}

struct CommaSeparated<'a, 's: 'a, 'o: 'a> {
    de: &'a mut Deserializer<'s, 'o>,
}

impl<'a, 's, 'o> CommaSeparated<'a, 's, 'o> {
    fn new(de: &'a mut Deserializer<'s, 'o>) -> Self {
        CommaSeparated { de }
    }
}

impl<'a, 's, 'o> SeqAccess<'s> for CommaSeparated<'a, 's, 'o> {
    type Error = Error;
    fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>
    where
        T: DeserializeSeed<'s>,
    {
        if self.de.input.is_empty() {
            return Ok(None);
        }
        seed.deserialize(&mut *self.de).map(Some)
    }
}

impl<'a, 's, 'o> MapAccess<'s> for CommaSeparated<'a, 's, 'o> {
    type Error = Error;

    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>>
    where
        K: DeserializeSeed<'s>,
    {
        if self.de.input.is_empty() {
            return Ok(None);
        }
        let Some(key) = self.de.consume_input_until('=') else {
            return Err(Error::ExpectedMapEq);
        };
        if key.contains(',') {
            return Err(Error::ExpectedMapEq);
        }
        self.de.key = key;
        let mut sub_de = Deserializer {
            input: key,
            key: "",
            ..*self.de
        };
        seed.deserialize(&mut sub_de).map(Some)
    }

    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value>
    where
        V: DeserializeSeed<'s>,
    {
        seed.deserialize(&mut *self.de)
    }
}

struct Enum<'a, 's: 'a, 'o: 'a> {
    de: &'a mut Deserializer<'s, 'o>,
}

impl<'a, 's, 'o> Enum<'a, 's, 'o> {
    fn new(de: &'a mut Deserializer<'s, 'o>) -> Self {
        Enum { de }
    }
}

impl<'a, 's, 'o> EnumAccess<'s> for Enum<'a, 's, 'o> {
    type Error = Error;
    type Variant = Self;

    fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant)>
    where
        V: DeserializeSeed<'s>,
    {
        let val = seed.deserialize(&mut *self.de)?;
        Ok((val, self))
    }
}

impl<'a, 's, 'o> VariantAccess<'s> for Enum<'a, 's, 'o> {
    type Error = Error;

    fn unit_variant(self) -> Result<()> {
        Ok(())
    }

    fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value>
    where
        T: DeserializeSeed<'s>,
    {
        self.de.top_level = true;
        seed.deserialize(self.de)
    }

    fn tuple_variant<V>(self, _len: usize, visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_seq(CommaSeparated::new(self.de))
    }

    fn struct_variant<V>(self, _fields: &'static [&'static str], visitor: V) -> Result<V::Value>
    where
        V: Visitor<'s>,
    {
        visitor.visit_map(CommaSeparated::new(self.de))
    }
}

#[cfg(test)]
mod test {
    use std::collections::HashMap;
    use std::marker::PhantomData;

    use assert_matches::assert_matches;
    use serde::Deserialize;
    use serde_bytes::{ByteArray, ByteBuf};

    use crate::{from_arg, from_args, Error};

    #[test]
    fn test_option() {
        assert_matches!(from_arg::<Option<u32>>(""), Err(Error::ExpectedInteger));
        assert_eq!(from_arg::<Option<u32>>("12").unwrap(), Some(12));

        assert_eq!(from_arg::<Option<&'static str>>("").unwrap(), Some(""));
        assert_eq!(
            from_args::<Option<&'static str>>("id_1", &HashMap::from([("id_1", "")])).unwrap(),
            None
        );
        assert_eq!(from_arg::<Option<&'static str>>("12").unwrap(), Some("12"));
        assert_matches!(
            from_arg::<Option<&'static str>>("id_1"),
            Err(Error::IdNotFound(id)) if id == "id_1"
        );
        assert_eq!(
            from_args::<Option<&'static str>>("id_1", &HashMap::from([("id_1", "id_2")])).unwrap(),
            Some("id_2")
        );

        let map_none = HashMap::from([("id_none", "")]);
        assert_eq!(from_arg::<Vec<Option<u32>>>("").unwrap(), vec![]);
        assert_eq!(
            from_args::<Vec<Option<u32>>>("id_none,", &map_none).unwrap(),
            vec![None]
        );
        assert_eq!(from_arg::<Vec<Option<u32>>>("1,").unwrap(), vec![Some(1)]);
        assert_eq!(
            from_arg::<Vec<Option<u32>>>("1,2,").unwrap(),
            vec![Some(1), Some(2)]
        );
        assert_eq!(
            from_args::<Vec<Option<u32>>>("1,2,id_none,", &map_none).unwrap(),
            vec![Some(1), Some(2), None]
        );
        assert_eq!(
            from_args::<Vec<Option<u32>>>("id_none,2", &map_none).unwrap(),
            vec![None, Some(2)]
        );
    }

    #[test]
    fn test_unit() {
        assert!(from_arg::<()>("").is_ok());
        assert_matches!(from_arg::<()>("unit"), Err(Error::ExpectedUnit));

        assert!(from_arg::<PhantomData<u8>>("").is_ok());
        assert_matches!(from_arg::<PhantomData<u8>>("12"), Err(Error::ExpectedUnit));

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct Param {
            p: PhantomData<u8>,
        }
        assert_eq!(from_arg::<Param>("p=").unwrap(), Param { p: PhantomData });
        assert_matches!(from_arg::<Param>("p=1,"), Err(Error::ExpectedUnit));
    }

    #[test]
    fn test_numbers() {
        assert_eq!(from_arg::<i8>("0").unwrap(), 0);
        assert_eq!(from_arg::<i8>("1").unwrap(), 1);
        assert_eq!(from_arg::<i8>("127").unwrap(), 127);
        assert_matches!(from_arg::<i8>("128"), Err(Error::Overflow));
        assert_eq!(from_arg::<i8>("-1").unwrap(), -1);
        assert_eq!(from_arg::<i8>("-128").unwrap(), -128);
        assert_matches!(from_arg::<i8>("-129"), Err(Error::Overflow));

        assert_eq!(from_arg::<i16>("1k").unwrap(), 1 << 10);

        assert_eq!(from_arg::<i32>("1g").unwrap(), 1 << 30);
        assert_matches!(from_arg::<i32>("2g"), Err(Error::Overflow));
        assert_matches!(from_arg::<i32>("0xffffffff"), Err(Error::Overflow));

        assert_eq!(from_arg::<i64>("0xffffffff").unwrap(), 0xffffffff);

        assert_matches!(from_arg::<i64>("gg"), Err(Error::ExpectedInteger));

        assert_matches!(from_arg::<f32>("0.125").unwrap(), 0.125);

        assert_matches!(from_arg::<f64>("-0.5").unwrap(), -0.5);
    }

    #[test]
    fn test_char() {
        assert_eq!(from_arg::<char>("=").unwrap(), '=');
        assert_eq!(from_arg::<char>("a").unwrap(), 'a');
        assert_matches!(from_arg::<char>("an"), Err(Error::Message(_)));

        assert_eq!(
            from_args::<HashMap<char, char>>(
                "id_1=a,b=id_2,id_2=id_1",
                &HashMap::from([("id_1", ","), ("id_2", "="),])
            )
            .unwrap(),
            HashMap::from([(',', 'a'), ('b', '='), ('=', ',')])
        );
    }

    #[test]
    fn test_bytes() {
        assert!(from_arg::<ByteArray<6>>("0xea,0xd7,0xa8,0xe8,0xc6,0x2f").is_ok());
        assert_matches!(
            from_arg::<ByteArray<5>>("0xea,0xd7,0xa8,0xe8,0xc6,0x2f"),
            Err(Error::Trailing(t)) if t == "0x2f"
        );
        assert_eq!(
            from_arg::<ByteBuf>("0xea,0xd7,0xa8,0xe8,0xc6,0x2f").unwrap(),
            vec![0xea, 0xd7, 0xa8, 0xe8, 0xc6, 0x2f]
        );

        #[derive(Debug, Deserialize, Eq, PartialEq)]
        struct MacAddr {
            addr: ByteArray<6>,
        }
        assert_eq!(
            from_args::<MacAddr>(
                "addr=id_addr",
                &HashMap::from([("id_addr", "0xea,0xd7,0xa8,0xe8,0xc6,0x2f")])
            )
            .unwrap(),
            MacAddr {
                addr: ByteArray::new([0xea, 0xd7, 0xa8, 0xe8, 0xc6, 0x2f])
            }
        )
    }

    #[test]
    fn test_string() {
        assert_eq!(
            from_arg::<String>("test,s=1,c").unwrap(),
            "test,s=1,c".to_owned()
        );
        assert_eq!(
            from_args::<HashMap<String, String>>(
                "cmd=id_1",
                &HashMap::from([("id_1", "console=ttyS0")])
            )
            .unwrap(),
            HashMap::from([("cmd".to_owned(), "console=ttyS0".to_owned())])
        )
    }

    #[test]
    fn test_seq() {
        assert_eq!(from_arg::<Vec<u32>>("").unwrap(), vec![]);

        assert_eq!(from_arg::<Vec<u32>>("1").unwrap(), vec![1]);

        assert_eq!(from_arg::<Vec<u32>>("1,2,3,4").unwrap(), vec![1, 2, 3, 4]);

        assert_eq!(from_arg::<(u16, bool)>("12,true").unwrap(), (12, true));
        assert_matches!(
            from_arg::<(u16, bool)>("12,true,false"),
            Err(Error::Trailing(t)) if t == "false"
        );

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct TestStruct {
            a: (u16, bool),
        }
        assert_eq!(
            from_args::<TestStruct>("a=id_a", &HashMap::from([("id_a", "12,true")])).unwrap(),
            TestStruct { a: (12, true) }
        );
        assert_matches!(
            from_args::<TestStruct>("a=id_a", &HashMap::from([("id_a", "12,true,true")])),
            Err(Error::Trailing(t)) if t == "true"
        );

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct Node {
            #[serde(default)]
            name: String,
            #[serde(default)]
            start: u64,
            size: u64,
        }
        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct Numa {
            nodes: Vec<Node>,
        }

        assert_eq!(
            from_args::<Numa>(
                "nodes=id_nodes",
                &HashMap::from([
                    ("id_nodes", "id_node1,id_node2"),
                    ("id_node1", "name=a,start=0,size=2g"),
                    ("id_node2", "name=b,start=4g,size=2g"),
                ])
            )
            .unwrap(),
            Numa {
                nodes: vec![
                    Node {
                        name: "a".to_owned(),
                        start: 0,
                        size: 2 << 30
                    },
                    Node {
                        name: "b".to_owned(),
                        start: 4 << 30,
                        size: 2 << 30
                    }
                ]
            }
        );

        assert_eq!(
            from_arg::<Numa>("nodes=size=2g,").unwrap(),
            Numa {
                nodes: vec![Node {
                    name: "".to_owned(),
                    start: 0,
                    size: 2 << 30
                }]
            }
        );

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct Info(bool, u32);

        assert_eq!(from_arg::<Info>("true,32").unwrap(), Info(true, 32));
    }

    #[test]
    fn test_map() {
        #[derive(Debug, Deserialize, PartialEq, Eq, Hash)]
        struct MapKey {
            name: String,
            id: u32,
        }
        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct MapVal {
            addr: String,
            info: HashMap<String, String>,
        }

        assert_matches!(
            from_arg::<MapKey>("name=a,id=1,addr=b"),
            Err(Error::Ignored(k)) if k == "addr"
        );
        assert_matches!(
            from_arg::<MapKey>("name=a,addr=b,id=1"),
            Err(Error::Ignored(k)) if k == "addr"
        );
        assert_matches!(from_arg::<MapKey>("name=a,ids=b"), Err(Error::Ignored(k)) if k == "ids");
        assert_matches!(from_arg::<MapKey>("name=a,ids=b,id=1"), Err(Error::Ignored(k)) if k == "ids");

        assert_eq!(
            from_args::<HashMap<MapKey, MapVal>>(
                "id_key1=id_val1,id_key2=id_val2",
                &HashMap::from([
                    ("id_key1", "name=gic,id=1"),
                    ("id_key2", "name=pci,id=2"),
                    ("id_val1", "addr=0xff,info=id_info1"),
                    ("id_info1", "compatible=id_gic,msi-controller=,#msi-cells=1"),
                    ("id_gic", "arm,gic-v3-its"),
                    ("id_val2", "addr=0xcc,info=compatible=pci-host-ecam-generic"),
                ])
            )
            .unwrap(),
            HashMap::from([
                (
                    MapKey {
                        name: "gic".to_owned(),
                        id: 1
                    },
                    MapVal {
                        addr: "0xff".to_owned(),
                        info: HashMap::from([
                            ("compatible".to_owned(), "arm,gic-v3-its".to_owned()),
                            ("msi-controller".to_owned(), "".to_owned()),
                            ("#msi-cells".to_owned(), "1".to_owned())
                        ])
                    }
                ),
                (
                    MapKey {
                        name: "pci".to_owned(),
                        id: 2
                    },
                    MapVal {
                        addr: "0xcc".to_owned(),
                        info: HashMap::from([(
                            "compatible".to_owned(),
                            "pci-host-ecam-generic".to_owned()
                        )])
                    }
                )
            ])
        );
    }

    #[test]
    fn test_nested_struct() {
        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct Param {
            byte: u8,
            word: u16,
            dw: u32,
            long: u64,
            enable_1: bool,
            enable_2: bool,
            enable_3: Option<bool>,
            sub: SubParam,
            addr: Addr,
        }

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct SubParam {
            b: u8,
            w: u16,
            enable: Option<bool>,
            s: String,
        }

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct Addr(u32);

        assert_eq!(
            from_args::<Param>(
                "byte=0b10,word=0o7k,dw=0x8m,long=10t,enable_1=on,enable_2=off,sub=id_1,addr=1g",
                &[("id_1", "b=1,w=2,s=s1,enable=on")].into()
            )
            .unwrap(),
            Param {
                byte: 0b10,
                word: 0o7 << 10,
                dw: 0x8 << 20,
                long: 10 << 40,
                enable_1: true,
                enable_2: false,
                enable_3: None,
                sub: SubParam {
                    b: 1,
                    w: 2,
                    enable: Some(true),
                    s: "s1".to_owned(),
                },
                addr: Addr(1 << 30)
            }
        );
        assert_matches!(
            from_arg::<SubParam>("b=1,w=2,enable,s=s1"),
            Err(Error::ExpectedMapEq)
        );
        assert_matches!(
            from_arg::<SubParam>("b=1,w=2,s=s1,enable"),
            Err(Error::ExpectedMapEq)
        );
    }

    #[test]
    fn test_bool() {
        assert_matches!(from_arg::<bool>("on"), Ok(true));
        assert_matches!(from_arg::<bool>("off"), Ok(false));
        assert_matches!(from_arg::<bool>("true"), Ok(true));
        assert_matches!(from_arg::<bool>("false"), Ok(false));
        assert_matches!(from_arg::<bool>("on,off"), Err(Error::Trailing(t)) if t == "off");

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct BoolStruct {
            val: bool,
        }
        assert_eq!(
            from_arg::<BoolStruct>("val=on").unwrap(),
            BoolStruct { val: true }
        );
        assert_eq!(
            from_arg::<BoolStruct>("val=off").unwrap(),
            BoolStruct { val: false }
        );
        assert_eq!(
            from_arg::<BoolStruct>("val=true").unwrap(),
            BoolStruct { val: true }
        );
        assert_eq!(
            from_arg::<BoolStruct>("val=false").unwrap(),
            BoolStruct { val: false }
        );
        assert_matches!(from_arg::<BoolStruct>("val=a"), Err(Error::ExpectedBool));

        assert_matches!(
            from_arg::<BoolStruct>("val=on,key=off"),
            Err(Error::Ignored(k)) if k == "key"
        );
    }

    #[test]
    fn test_enum() {
        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct SubStruct {
            a: u32,
            b: bool,
        }

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        enum TestEnum {
            A {
                #[serde(default)]
                val: u32,
            },
            B(u64),
            C(u8, u8),
            D,
            #[serde(alias = "e")]
            E,
            F(SubStruct),
            G(u16, String, bool),
        }

        #[derive(Debug, Deserialize, PartialEq, Eq)]
        struct TestStruct {
            num: u32,
            e: TestEnum,
        }

        assert_eq!(
            from_args::<TestStruct>("num=3,e=id_a", &[("id_a", "A,val=1")].into()).unwrap(),
            TestStruct {
                num: 3,
                e: TestEnum::A { val: 1 }
            }
        );
        assert_eq!(
            from_arg::<TestStruct>("num=4,e=A").unwrap(),
            TestStruct {
                num: 4,
                e: TestEnum::A { val: 0 },
            }
        );
        assert_eq!(
            from_args::<TestStruct>("num=4,e=id_a", &[("id_a", "A")].into()).unwrap(),
            TestStruct {
                num: 4,
                e: TestEnum::A { val: 0 },
            }
        );
        assert_eq!(
            from_arg::<TestStruct>("num=4,e=D").unwrap(),
            TestStruct {
                num: 4,
                e: TestEnum::D,
            }
        );
        assert_eq!(
            from_args::<TestStruct>("num=4,e=id_d", &[("id_d", "D")].into()).unwrap(),
            TestStruct {
                num: 4,
                e: TestEnum::D,
            }
        );
        assert_eq!(
            from_arg::<TestStruct>("num=3,e=e").unwrap(),
            TestStruct {
                num: 3,
                e: TestEnum::E
            }
        );
        assert_matches!(
            from_arg::<TestStruct>("num=4,e=id_d"),
            Err(Error::IdNotFound(id)) if id == "id_d"
        );
        assert_matches!(
            from_args::<TestStruct>("num=4,e=id_d", &[].into()),
            Err(Error::IdNotFound(id)) if id == "id_d"
        );
        assert_eq!(from_arg::<TestEnum>("B,1").unwrap(), TestEnum::B(1));
        assert_eq!(from_arg::<TestEnum>("D").unwrap(), TestEnum::D);
        assert_eq!(
            from_arg::<TestEnum>("F,a=1,b=on").unwrap(),
            TestEnum::F(SubStruct { a: 1, b: true })
        );
        assert_eq!(
            from_arg::<TestEnum>("G,1,a,true").unwrap(),
            TestEnum::G(1, "a".to_owned(), true)
        );
        assert_matches!(
            from_arg::<TestEnum>("G,1,a,true,false"),
            Err(Error::Trailing(t)) if t == "false"
        );
        assert_matches!(
            from_args::<TestStruct>(
                "num=4,e=id_e",
                &HashMap::from([("id_e", "G,1,a,true,false")])
            ),
            Err(Error::Trailing(t)) if t == "false"
        );
    }
}