use crate::abi_example::{normalize_type_name, AbiEnumVisitor};
use crate::hash::{Hash, Hasher};

use log::*;

use serde::ser::Error as SerdeError;
use serde::ser::*;
use serde::{Serialize, Serializer};

use std::any::type_name;
use std::io::Write;

use thiserror::Error;

#[derive(Debug)]
pub struct AbiDigester {
    data_types: std::rc::Rc<std::cell::RefCell<Vec<String>>>,
    depth: usize,
    for_enum: bool,
    opaque_scope: Option<String>,
}

pub type DigestResult = Result<AbiDigester, DigestError>;
type Sstr = &'static str;

#[derive(Debug, Error)]
pub enum DigestError {
    #[error("Option::None is serialized; no ABI digest for Option::Some")]
    NoneIsSerialized,
    #[error("nested error")]
    Node(Sstr, Box<DigestError>),
    #[error("leaf error")]
    Leaf(Sstr, Sstr, Box<DigestError>),
}

impl SerdeError for DigestError {
    fn custom<T: std::fmt::Display>(_msg: T) -> DigestError {
        unreachable!("This error should never be used");
    }
}

impl DigestError {
    pub(crate) fn wrap_by_type<T: ?Sized>(e: DigestError) -> DigestError {
        DigestError::Node(type_name::<T>(), Box::new(e))
    }

    pub(crate) fn wrap_by_str(e: DigestError, s: Sstr) -> DigestError {
        DigestError::Node(s, Box::new(e))
    }
}

const INDENT_WIDTH: usize = 4;

impl AbiDigester {
    pub fn create() -> Self {
        AbiDigester {
            data_types: std::rc::Rc::new(std::cell::RefCell::new(vec![])),
            for_enum: false,
            depth: 0,
            opaque_scope: None,
        }
    }

    // must create separate instances because we can't pass the single instance to
    // `.serialize()` multiple times
    pub fn create_new(&self) -> Self {
        Self {
            data_types: self.data_types.clone(),
            depth: self.depth,
            for_enum: false,
            opaque_scope: self.opaque_scope.clone(),
        }
    }

    pub fn create_new_opaque(&self, top_scope: &str) -> Self {
        Self {
            data_types: self.data_types.clone(),
            depth: self.depth,
            for_enum: false,
            opaque_scope: Some(top_scope.to_owned()),
        }
    }

    pub fn create_child(&self) -> Self {
        Self {
            data_types: self.data_types.clone(),
            depth: self.depth + 1,
            for_enum: false,
            opaque_scope: self.opaque_scope.clone(),
        }
    }

    pub fn create_enum_child(&self) -> Self {
        Self {
            data_types: self.data_types.clone(),
            depth: self.depth + 1,
            for_enum: true,
            opaque_scope: self.opaque_scope.clone(),
        }
    }

    pub fn digest_data<T: ?Sized + Serialize>(&mut self, value: &T) -> DigestResult {
        let type_name = normalize_type_name(type_name::<T>());
        if type_name.ends_with("__SerializeWith")
            || (self.opaque_scope.is_some()
                && type_name.starts_with(self.opaque_scope.as_ref().unwrap()))
        {
            // we can't use the AbiEnumVisitor trait for these cases.
            value.serialize(self.create_new())
        } else {
            // Don't call value.visit_for_abi(...) to prefer autoref specialization
            // resolution for IgnoreAsHelper
            <&T>::visit_for_abi(&value, &mut self.create_new())
        }
    }

    pub fn update(&mut self, strs: &[&str]) {
        let mut buf = strs
            .iter()
            .map(|s| {
                // this is a bit crude, but just normalize all strings as if they're
                // `type_name`s!
                normalize_type_name(s)
            })
            .collect::<Vec<_>>()
            .join(" ");
        buf = format!("{:0width$}{}\n", "", buf, width = self.depth * INDENT_WIDTH);
        info!("updating with: {}", buf.trim_end());
        (*self.data_types.borrow_mut()).push(buf);
    }

    pub fn update_with_type<T: ?Sized>(&mut self, label: &str) {
        self.update(&[label, type_name::<T>()]);
    }

    pub fn update_with_string(&mut self, label: String) {
        self.update(&[&label]);
    }

    fn digest_primitive<T: Serialize>(mut self) -> Result<AbiDigester, DigestError> {
        self.update_with_type::<T>("primitive");
        Ok(self)
    }

    fn digest_element<T: ?Sized + Serialize>(&mut self, v: &T) -> Result<(), DigestError> {
        self.update_with_type::<T>("element");
        self.create_child().digest_data(v).map(|_| ())
    }

    fn digest_named_field<T: ?Sized + Serialize>(
        &mut self,
        key: Sstr,
        v: &T,
    ) -> Result<(), DigestError> {
        self.update_with_string(format!("field {}: {}", key, type_name::<T>()));
        self.create_child()
            .digest_data(v)
            .map(|_| ())
            .map_err(|e| DigestError::wrap_by_str(e, key))
    }

    fn digest_unnamed_field<T: ?Sized + Serialize>(&mut self, v: &T) -> Result<(), DigestError> {
        self.update_with_type::<T>("field");
        self.create_child().digest_data(v).map(|_| ())
    }

    fn check_for_enum(
        &mut self,
        label: &'static str,
        variant: &'static str,
    ) -> Result<(), DigestError> {
        if !self.for_enum {
            panic!("derive AbiEnumVisitor or implement it for the enum, which contains a variant ({}) named {}", label, variant);
        }
        Ok(())
    }

    pub fn finalize(self) -> Hash {
        let mut hasher = Hasher::default();

        for buf in (*self.data_types.borrow()).iter() {
            hasher.hash(buf.as_bytes());
        }

        let hash = hasher.result();

        if let Ok(dir) = std::env::var("SOLANA_ABI_DUMP_DIR") {
            let thread_name = std::thread::current()
                .name()
                .unwrap_or("unknown-test-thread")
                .replace(':', "_");
            if thread_name == "main" {
                error!("Bad thread name detected for dumping; Maybe, --test-threads=1? Sorry, SOLANA_ABI_DUMP_DIR doesn't work under 1; increase it");
            }

            let path = format!("{}/{}_{}", dir, thread_name, hash,);
            let mut file = std::fs::File::create(path).unwrap();
            for buf in (*self.data_types.borrow()).iter() {
                file.write_all(buf.as_bytes()).unwrap();
            }
            file.sync_data().unwrap();
        }

        hash
    }
}

impl Serializer for AbiDigester {
    type Ok = Self;
    type Error = DigestError;
    type SerializeSeq = Self;
    type SerializeTuple = Self;
    type SerializeTupleStruct = Self;
    type SerializeTupleVariant = Self;
    type SerializeMap = Self;
    type SerializeStruct = Self;
    type SerializeStructVariant = Self;

    fn serialize_bool(self, _data: bool) -> DigestResult {
        self.digest_primitive::<bool>()
    }

    fn serialize_i8(self, _data: i8) -> DigestResult {
        self.digest_primitive::<i8>()
    }

    fn serialize_i16(self, _data: i16) -> DigestResult {
        self.digest_primitive::<i16>()
    }

    fn serialize_i32(self, _data: i32) -> DigestResult {
        self.digest_primitive::<i32>()
    }

    fn serialize_i64(self, _data: i64) -> DigestResult {
        self.digest_primitive::<i64>()
    }

    fn serialize_i128(self, _data: i128) -> DigestResult {
        self.digest_primitive::<i128>()
    }

    fn serialize_u8(self, _data: u8) -> DigestResult {
        self.digest_primitive::<u8>()
    }

    fn serialize_u16(self, _data: u16) -> DigestResult {
        self.digest_primitive::<u16>()
    }

    fn serialize_u32(self, _data: u32) -> DigestResult {
        self.digest_primitive::<u32>()
    }

    fn serialize_u64(self, _data: u64) -> DigestResult {
        self.digest_primitive::<u64>()
    }

    fn serialize_u128(self, _data: u128) -> DigestResult {
        self.digest_primitive::<u128>()
    }

    fn serialize_f32(self, _data: f32) -> DigestResult {
        self.digest_primitive::<f32>()
    }

    fn serialize_f64(self, _data: f64) -> DigestResult {
        self.digest_primitive::<f64>()
    }

    fn serialize_char(self, _data: char) -> DigestResult {
        self.digest_primitive::<char>()
    }

    fn serialize_str(self, _data: &str) -> DigestResult {
        self.digest_primitive::<&str>()
    }

    fn serialize_unit(self) -> DigestResult {
        self.digest_primitive::<()>()
    }

    fn serialize_bytes(mut self, v: &[u8]) -> DigestResult {
        self.update_with_string(format!("bytes [u8] (len = {})", v.len()));
        Ok(self)
    }

    fn serialize_none(self) -> DigestResult {
        Err(DigestError::NoneIsSerialized)
    }

    fn serialize_some<T>(mut self, v: &T) -> DigestResult
    where
        T: ?Sized + Serialize,
    {
        // emulate the ABI digest for the Option enum; see TestMyOption
        self.update(&["enum Option (variants = 2)"]);
        let mut variant_digester = self.create_child();

        variant_digester.update_with_string("variant(0) None (unit)".to_owned());
        variant_digester
            .update_with_string(format!("variant(1) Some({}) (newtype)", type_name::<T>()));
        variant_digester.create_child().digest_data(v)
    }

    fn serialize_unit_struct(mut self, name: Sstr) -> DigestResult {
        self.update(&["struct", name, "(unit)"]);
        Ok(self)
    }

    fn serialize_unit_variant(mut self, _name: Sstr, index: u32, variant: Sstr) -> DigestResult {
        self.check_for_enum("unit_variant", variant)?;
        self.update_with_string(format!("variant({}) {} (unit)", index, variant));
        Ok(self)
    }

    fn serialize_newtype_struct<T>(mut self, name: Sstr, v: &T) -> DigestResult
    where
        T: ?Sized + Serialize,
    {
        self.update_with_string(format!("struct {}({}) (newtype)", name, type_name::<T>()));
        self.create_child()
            .digest_data(v)
            .map_err(|e| DigestError::wrap_by_str(e, "newtype_struct"))
    }

    fn serialize_newtype_variant<T>(
        mut self,
        _name: Sstr,
        i: u32,
        variant: Sstr,
        v: &T,
    ) -> DigestResult
    where
        T: ?Sized + Serialize,
    {
        self.check_for_enum("newtype_variant", variant)?;
        self.update_with_string(format!(
            "variant({}) {}({}) (newtype)",
            i,
            variant,
            type_name::<T>()
        ));
        self.create_child()
            .digest_data(v)
            .map_err(|e| DigestError::wrap_by_str(e, "newtype_variant"))
    }

    fn serialize_seq(mut self, len: Option<usize>) -> DigestResult {
        let len = len.unwrap();
        assert_eq!(
            len, 1,
            "Exactly 1 seq element is needed to generate the ABI digest precisely"
        );
        self.update_with_string(format!("seq (elements = {})", len));
        Ok(self.create_child())
    }

    fn serialize_tuple(mut self, len: usize) -> DigestResult {
        self.update_with_string(format!("tuple (elements = {})", len));
        Ok(self.create_child())
    }

    fn serialize_tuple_struct(mut self, name: Sstr, len: usize) -> DigestResult {
        self.update_with_string(format!("struct {} (fields = {}) (tuple)", name, len));
        Ok(self.create_child())
    }

    fn serialize_tuple_variant(
        mut self,
        _name: Sstr,
        i: u32,
        variant: Sstr,
        len: usize,
    ) -> DigestResult {
        self.check_for_enum("tuple_variant", variant)?;
        self.update_with_string(format!("variant({}) {} (fields = {})", i, variant, len));
        Ok(self.create_child())
    }

    fn serialize_map(mut self, len: Option<usize>) -> DigestResult {
        let len = len.unwrap();
        assert_eq!(
            len, 1,
            "Exactly 1 map entry is needed to generate the ABI digest precisely"
        );
        self.update_with_string(format!("map (entries = {})", len));
        Ok(self.create_child())
    }

    fn serialize_struct(mut self, name: Sstr, len: usize) -> DigestResult {
        self.update_with_string(format!("struct {} (fields = {})", name, len));
        Ok(self.create_child())
    }

    fn serialize_struct_variant(
        mut self,
        _name: Sstr,
        i: u32,
        variant: Sstr,
        len: usize,
    ) -> DigestResult {
        self.check_for_enum("struct_variant", variant)?;
        self.update_with_string(format!(
            "variant({}) struct {} (fields = {})",
            i, variant, len
        ));
        Ok(self.create_child())
    }
}

impl SerializeSeq for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_element<T: ?Sized + Serialize>(&mut self, data: &T) -> Result<(), DigestError> {
        self.digest_element(data)
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}

impl SerializeTuple for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_element<T: ?Sized + Serialize>(&mut self, data: &T) -> Result<(), DigestError> {
        self.digest_element(data)
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}
impl SerializeTupleStruct for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_field<T: ?Sized + Serialize>(&mut self, data: &T) -> Result<(), DigestError> {
        self.digest_unnamed_field(data)
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}

impl SerializeTupleVariant for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_field<T: ?Sized + Serialize>(&mut self, data: &T) -> Result<(), DigestError> {
        self.digest_unnamed_field(data)
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}

impl SerializeMap for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_key<T: ?Sized + Serialize>(&mut self, key: &T) -> Result<(), DigestError> {
        self.update_with_type::<T>("key");
        self.create_child().digest_data(key).map(|_| ())
    }

    fn serialize_value<T: ?Sized + Serialize>(&mut self, value: &T) -> Result<(), DigestError> {
        self.update_with_type::<T>("value");
        self.create_child().digest_data(value).map(|_| ())
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}

impl SerializeStruct for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_field<T: ?Sized + Serialize>(
        &mut self,
        key: Sstr,
        data: &T,
    ) -> Result<(), DigestError> {
        self.digest_named_field(key, data)
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}

impl SerializeStructVariant for AbiDigester {
    type Ok = Self;
    type Error = DigestError;

    fn serialize_field<T: ?Sized + Serialize>(
        &mut self,
        key: Sstr,
        data: &T,
    ) -> Result<(), DigestError> {
        self.digest_named_field(key, data)
    }

    fn end(self) -> DigestResult {
        Ok(self)
    }
}

#[cfg(test)]
mod tests {
    use std::collections::HashMap;
    use std::sync::atomic::AtomicIsize;

    #[frozen_abi(digest = "CQiGCzsGquChkwffHjZKFqa3tCYtS3GWYRRYX7iDR38Q")]
    type TestTypeAlias = i32;

    #[frozen_abi(digest = "Apwkp9Ah9zKirzwuSzVoU9QRc43EghpkD1nGVakJLfUY")]
    #[derive(Serialize, AbiExample)]
    struct TestStruct {
        test_field: i8,
        test_field2: i8,
    }

    #[frozen_abi(digest = "4LbuvQLX78XPbm4hqqZcHFHpseDJcw4qZL9EUZXSi2Ss")]
    #[derive(Serialize, AbiExample)]
    struct TestTupleStruct(i8, i8);

    #[frozen_abi(digest = "FNHa6mNYJZa59Fwbipep5dXRXcFreaDHn9jEUZEH1YLv")]
    #[derive(Serialize, AbiExample)]
    struct TestNewtypeStruct(i8);

    #[frozen_abi(digest = "5qio5qYurHDv6fq5kcwP2ue2RBEazSZF8CPk2kUuwC2j")]
    #[derive(Serialize, AbiExample)]
    struct TestStructReversed {
        test_field2: i8,
        test_field: i8,
    }

    #[frozen_abi(digest = "DLLrTWprsMjdJGR447A4mui9HpqxbKdsFXBfaWPcwhny")]
    #[derive(Serialize, AbiExample)]
    struct TestStructAnotherType {
        test_field: i16,
        test_field2: i8,
    }

    #[frozen_abi(digest = "GMeECsxg37a5qznstWXeeX3d6HXs6j12oB4SKaZZuNJk")]
    #[derive(Serialize, AbiExample)]
    struct TestNest {
        nested_field: [TestStruct; 5],
    }

    #[frozen_abi(digest = "GttWH8FAY3teUjTaSds9mL3YbiDQ7qWw7WAvDXKd4ZzX")]
    type TestUnitStruct = std::marker::PhantomData<i8>;

    #[frozen_abi(digest = "2zvXde11f8sNnFbc9E6ZZeFxV7D2BTVLKEZmNTsCDBpS")]
    #[derive(Serialize, AbiExample, AbiEnumVisitor)]
    enum TestEnum {
        VARIANT1,
        VARIANT2,
    }

    #[frozen_abi(digest = "6keb3v7GXLahhL6zoinzCWwSvB3KhmvZMB3tN2mamAm3")]
    #[derive(Serialize, AbiExample, AbiEnumVisitor)]
    enum TestTupleVariant {
        VARIANT1(u8, u16),
        VARIANT2(u8, u16),
    }

    #[frozen_abi(digest = "DywMfwKq8HZCbUfTwnemHWMN8LvMZCvipQuLddQ2ywwG")]
    #[derive(Serialize, AbiExample)]
    struct TestVecEnum {
        enums: Vec<TestTupleVariant>,
    }

    #[derive(Serialize, AbiExample)]
    struct TestGenericStruct<T: Ord> {
        test_field: T,
    }

    #[frozen_abi(digest = "2Dr5k3Z513mV4KrGeUfcMwjsVHLmVyLiZarmfnXawEbf")]
    type TestConcreteStruct = TestGenericStruct<i64>;

    #[derive(Serialize, AbiExample, AbiEnumVisitor)]
    enum TestGenericEnum<T: serde::Serialize + Sized + Ord> {
        TestVariant(T),
    }

    #[frozen_abi(digest = "2B2HqxHaziSfW3kdxJqV9vEMpCpRaEipXL6Bskv1GV7J")]
    type TestConcreteEnum = TestGenericEnum<u128>;

    #[frozen_abi(digest = "GyExD8nkYb9e6tijFL5S1gFtdN9GfY6L2sUDjTLhVGn4")]
    type TestMap = HashMap<char, i128>;

    #[frozen_abi(digest = "AFLTVyVBkjc1SAPnzyuwTvmie994LMhJGN7PrP7hCVwL")]
    type TestVec = Vec<f32>;

    #[frozen_abi(digest = "F5RniBQtNMBiDnyLEf72aQKHskV1TuBrD4jrEH5odPAW")]
    type TestArray = [f64; 10];

    #[frozen_abi(digest = "8cgZGpckC4dFovh3QuZpgvcvK2125ig7P4HsK9KCw39N")]
    type TestUnit = ();

    #[frozen_abi(digest = "FgnBPy2T5iNNbykMteq1M4FRpNeSkzRoi9oXeCjEW6uq")]
    type TestResult = Result<u8, u16>;

    #[frozen_abi(digest = "F5s6YyJkfz7LM56q5j9RzTLa7QX4Utx1ecNkHX5UU9Fp")]
    type TestAtomic = AtomicIsize;

    #[frozen_abi(digest = "7rH7gnEhJ8YouzqPT6VPyUDELvL51DGednSPcoLXG2rg")]
    type TestOptionWithIsize = Option<isize>;

    #[derive(Serialize, AbiExample, AbiEnumVisitor)]
    enum TestMyOption<T: serde::Serialize + Sized + Ord> {
        None,
        Some(T),
    }
    #[frozen_abi(digest = "BzXkoRacijFTCPW4PyyvhkqMVgcuhmvPXjZfMsHJCeet")]
    type TestMyOptionWithIsize = TestMyOption<isize>;

    #[frozen_abi(digest = "9PMdHRb49BpkywrmPoJyZWMsEmf5E1xgmsFGkGmea5RW")]
    type TestBitVec = bv::BitVec<u64>;

    mod skip_should_be_same {
        #[frozen_abi(digest = "4LbuvQLX78XPbm4hqqZcHFHpseDJcw4qZL9EUZXSi2Ss")]
        #[derive(Serialize, AbiExample)]
        struct TestTupleStruct(i8, i8, #[serde(skip)] i8);

        #[frozen_abi(digest = "Hk7BYjZ71upWQJAx2PqoNcapggobPmFbMJd34xVdvRso")]
        #[derive(Serialize, AbiExample)]
        struct TestStruct {
            test_field: i8,
            #[serde(skip)]
            _skipped_test_field: i8,
        }

        #[frozen_abi(digest = "2zvXde11f8sNnFbc9E6ZZeFxV7D2BTVLKEZmNTsCDBpS")]
        #[derive(Serialize, AbiExample, AbiEnumVisitor)]
        enum TestEnum {
            VARIANT1,
            VARIANT2,
            #[serde(skip)]
            #[allow(dead_code)]
            VARIANT3,
        }

        #[frozen_abi(digest = "6keb3v7GXLahhL6zoinzCWwSvB3KhmvZMB3tN2mamAm3")]
        #[derive(Serialize, AbiExample, AbiEnumVisitor)]
        enum TestTupleVariant {
            VARIANT1(u8, u16),
            VARIANT2(u8, u16, #[serde(skip)] u32),
        }
    }
}