// Copyright 2026 The NativeLink Authors. All rights reserved.

//

// Licensed under the Functional Source License, Version 1.1, Apache 2.0 Future License (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//    See LICENSE file for details

//

// 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 core::fmt::Write;

use core::hash::BuildHasher;

use std::collections::HashMap;

use nativelink_util::background_spawn;

use redis::Value;

use redis_test::IntoRedisValue;

use tokio::io::{AsyncReadExt, AsyncWriteExt};

use tokio::net::TcpListener;

use tracing::{error, info, warn};

fn cmd_as_string(cmd: &redis::Cmd) -> String {

    let raw = cmd.get_packed_command();

    String::from_utf8(raw).unwrap()

}

pub(crate) fn arg_as_string(output: &mut String, arg: Value) {

    match arg {

        Value::SimpleString(s) => {

            write!(output, "+{s}\r\n").unwrap();

        }

        Value::Okay => {

            write!(output, "+OK\r\n").unwrap();

        }

        Value::BulkString(s) => {

            write!(

                output,

                "${}\r\n{}\r\n",

                s.len(),

                str::from_utf8(&s).unwrap()

            )

            .unwrap();

        }

        Value::Int(v) => {

            write!(output, ":{v}\r\n").unwrap();

        }

        Value::Array(values) => {

            write!(output, "*{}\r\n", values.len()).unwrap();

            for value in 
values187
 {

                arg_as_string(output, value);

            }

        }

        Value::Map(values) => {

            write!(output, "%{}\r\n", values.len()).unwrap();

            for (key, value) in 
values52
 {

                arg_as_string(output, key);

                arg_as_string(output, value);

            }

        }

        Value::Nil => {

            write!(output, "_\r\n").unwrap();

        }

        Value::Boolean(value) => {

            if value {

                write!(output, "#t\r\n")

            } else {

                write!(output, "#f\r\n")

            }

            .unwrap();

        }

        _ => {

            panic!("No support for {arg:?}")

        }

    }

}

fn args_as_string(args: Vec<Value>) -> String {

    let mut output = String::new();

    for arg in 
args65
 {

        arg_as_string(&mut output, arg);

    }

    output

}

pub fn add_to_response<B: BuildHasher>(

    response: &mut HashMap<String, String, B>,

    cmd: &redis::Cmd,

    args: Vec<Value>,

) {

    add_to_response_raw(response, cmd, args_as_string(args));

}

pub fn add_to_response_raw<B: BuildHasher>(

    response: &mut HashMap<String, String, B>,

    cmd: &redis::Cmd,

    args: String,

) {

    response.insert(cmd_as_string(cmd), args);

}

fn setinfo(responses: &mut HashMap<String, String>) {

    // We do raw inserts of command here, because the library sends 3/4 commands in one go

    // They always start with HELLO, then optionally SELECT, so we use this to differentiate

    let hello = cmd_as_string(redis::cmd("HELLO").arg("3"));

    let setinfo = cmd_as_string(

        redis::cmd("CLIENT")

            .arg("SETINFO")

            .arg("LIB-NAME")

            .arg("redis-rs"),

    );

    responses.insert(

        [hello.clone(), setinfo.clone()].join(""),

        args_as_string(vec![

            Value::Map(vec![(

                Value::SimpleString("server".into()),

                Value::SimpleString("redis".into()),

            )]),

            Value::Okay,

            Value::Okay,

        ]),

    );

    responses.insert(

        [hello, cmd_as_string(redis::cmd("SELECT").arg(3)), setinfo].join(""),

        args_as_string(vec![

            Value::Map(vec![(

                Value::SimpleString("server".into()),

                Value::SimpleString("redis".into()),

            )]),

            Value::Okay,

            Value::Okay,

            Value::Okay,

        ]),

    );

}

pub fn add_lua_script<B: BuildHasher>(

    responses: &mut HashMap<String, String, B>,

    lua_script: &str,

    hash: &str,

) {

    add_to_response(

        responses,

        redis::cmd("SCRIPT").arg("LOAD").arg(lua_script),

        vec![hash.into_redis_value()],

    );

}

pub fn fake_redis_stream() -> HashMap<String, String> {

    let mut responses = HashMap::new();

    setinfo(&mut responses);

    // Does setinfo as well, so need to respond to all 3

    add_to_response(

        &mut responses,

        redis::cmd("SELECT").arg("3"),

        vec![Value::Okay, Value::Okay, Value::Okay],

    );

    responses

}

pub fn fake_redis_sentinel_master_stream() -> HashMap<String, String> {

    let mut response = fake_redis_stream();

    add_to_response(

        &mut response,

        &redis::cmd("ROLE"),

        vec![Value::Array(vec![

            "master".into_redis_value(),

            0.into_redis_value(),

            Value::Array(vec![]),

        ])],

    );

    response

}

pub fn fake_redis_sentinel_stream(master_name: &str, redis_port: u16) -> HashMap<String, String> {

    let mut response = HashMap::new();

    setinfo(&mut response);

    // Not a full "sentinel masters" response, but enough for redis-rs

    let resp: Vec<(Value, Value)> = vec![

        ("name".into_redis_value(), master_name.into_redis_value()),

        ("ip".into_redis_value(), "127.0.0.1".into_redis_value()),

        (

            "port".into_redis_value(),

            i64::from(redis_port).into_redis_value(),

        ),

        ("flags".into_redis_value(), "master".into_redis_value()),

    ];

    add_to_response(

        &mut response,

        redis::cmd("SENTINEL").arg("MASTERS"),

        vec![Value::Array(vec![Value::Map(resp)])],

    );

    response

}

pub(crate) async fn fake_redis_internal<H>(listener: TcpListener, handlers: Vec<H>)

where

    H: Fn(&[u8]) -> String + Send + Clone + 'static + Sync,

{

    let mut handler_iter = handlers.iter().cloned().cycle();

    loop {

        info!(

            "Waiting for connection on {}",

            listener.local_addr().unwrap()

        );

        let Ok((
mut stream36
, _)) = listener.accept().await else {

            error!("accept error");

            panic!("error");

        };

        info!("Accepted new connection");

        let local_handler = handler_iter.next().unwrap();

        background_spawn!("thread", async move {

            loop {

                let mut buf = vec![0; 8192];

                let 
res100k
 = stream.read(&mut buf).await.
unwrap100k
();

                if res != 0 {

                    let output = local_handler(&buf[..res]);

                    if !output.is_empty() {

                        stream.write_all(output.as_bytes()).await.unwrap();

                    }

                }

            }

        });

    }

}

async fn fake_redis<B>(listener: TcpListener, all_responses: Vec<HashMap<String, String, B>>)

where

    B: BuildHasher + Clone + Send + 'static + Sync,

{

    let funcs = all_responses

        .iter()

        .map(|responses| {

            info!("Responses are: {:?}", responses);

            let values = responses.clone();

            move |buf: &[u8]| -> String {

                let str_buf = String::from_utf8_lossy(buf).into_owned();

                for (key, value) in 
&values180
 {

                    if str_buf.starts_with(key) {

                        info!("Responding to {}", str_buf.replace("\r\n", "\\r\\n"));

                        return value.clone();

                    }

                }

                warn!(

                    "Unknown command: {}",

                    str_buf.chars().take(1000).collect::<String>()

                );

                String::new()

            }

        })

        .collect();

    fake_redis_internal(listener, funcs).await;

}

async fn make_fake_redis_with_multiple_responses<B: BuildHasher + Clone + Send + 'static + Sync>(

    responses: Vec<HashMap<String, String, B>>,

) -> u16 {

    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();

    let port = listener.local_addr().unwrap().port();

    info!(port, "Fake redis booted");

    background_spawn!("listener", async move {

        fake_redis(listener, responses).await;

    });

    port

}

pub async fn make_fake_redis_with_responses<B: BuildHasher + Clone + Send + 'static + Sync>(

    responses: HashMap<String, String, B>,

) -> u16 {

    make_fake_redis_with_multiple_responses(vec![responses]).await

}