use std::collections::HashMap;
use std::path::PathBuf;

use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
use codex_utils_pty::DEFAULT_OUTPUT_BYTES_CAP;
use serde::Deserialize;
use serde::Serialize;

pub const INITIALIZE_METHOD: &str = "initialize";
pub const INITIALIZED_METHOD: &str = "initialized";
pub const EXEC_METHOD: &str = "command/exec";
pub const EXEC_WRITE_METHOD: &str = "command/exec/write";
pub const EXEC_TERMINATE_METHOD: &str = "command/exec/terminate";
pub const EXEC_OUTPUT_DELTA_METHOD: &str = "command/exec/outputDelta";
pub const EXEC_EXITED_METHOD: &str = "command/exec/exited";
pub const PROTOCOL_VERSION: &str = "exec-server.v0";

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(transparent)]
pub struct ByteChunk(#[serde(with = "base64_bytes")] pub Vec<u8>);

impl ByteChunk {
    pub fn into_inner(self) -> Vec<u8> {
        self.0
    }
}

impl From<Vec<u8>> for ByteChunk {
    fn from(value: Vec<u8>) -> Self {
        Self(value)
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct InitializeParams {
    pub client_name: String,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct InitializeResponse {
    pub protocol_version: String,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ExecParams {
    pub process_id: String,
    pub argv: Vec<String>,
    pub cwd: PathBuf,
    pub env: HashMap<String, String>,
    pub tty: bool,
    #[serde(default = "default_output_bytes_cap")]
    pub output_bytes_cap: usize,
    pub arg0: Option<String>,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ExecResponse {
    pub process_id: String,
    pub running: bool,
    pub exit_code: Option<i32>,
    pub stdout: Option<ByteChunk>,
    pub stderr: Option<ByteChunk>,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct WriteParams {
    pub process_id: String,
    pub chunk: ByteChunk,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct WriteResponse {
    pub accepted: bool,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct TerminateParams {
    pub process_id: String,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct TerminateResponse {
    pub running: bool,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum ExecOutputStream {
    Stdout,
    Stderr,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ExecOutputDeltaNotification {
    pub process_id: String,
    pub stream: ExecOutputStream,
    pub chunk: ByteChunk,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ExecExitedNotification {
    pub process_id: String,
    pub exit_code: i32,
}

fn default_output_bytes_cap() -> usize {
    DEFAULT_OUTPUT_BYTES_CAP
}

mod base64_bytes {
    use super::BASE64_STANDARD;
    use base64::Engine as _;
    use serde::Deserialize;
    use serde::Deserializer;
    use serde::Serializer;

    pub fn serialize<S>(bytes: &[u8], serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_str(&BASE64_STANDARD.encode(bytes))
    }

    pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
    where
        D: Deserializer<'de>,
    {
        let encoded = String::deserialize(deserializer)?;
        BASE64_STANDARD
            .decode(encoded)
            .map_err(serde::de::Error::custom)
    }
}