//! Raw discovery and lifecycle guest for activation protocol tests.
use serde_json::{Value, json};
use std::io::{self, BufRead, Write};
/// Emits one flushed JSON-RPC response.
fn send(value: Value) {
    println!("{value}");
    io::stdout().flush().unwrap();
}
/// Calls a provider after activation releases an old consumer process.
fn deferred(request: &Value, plugin: &str, lines: &mut impl Iterator<Item = io::Result<String>>) {
    send(
        json!({"jsonrpc":"2.0","id":request["id"],"result":std::env::var("SAUSAGE_PID").unwrap()}),
    );
    while !std::path::Path::new(&format!("/state/{plugin}/release-call")).exists() {
        std::thread::sleep(std::time::Duration::from_millis(1));
    }
    send(json!({"jsonrpc":"2.0","id":"deferred","method":"notes.legacy","params":{}}));
    for line in lines {
        let response: Value = serde_json::from_str(&line.unwrap()).unwrap();
        if response["id"] == "deferred" {
            std::fs::write(format!("/state/{plugin}/call-result"), response.to_string()).unwrap();
            break;
        }
    }
}
/// Answers a method that version two removes from its interface.
fn legacy(request: &Value, document: &Value, version: &str) {
    if document["methods"]
        .as_array()
        .unwrap()
        .iter()
        .any(|m| m["name"] == "legacy")
    {
        send(json!({"jsonrpc":"2.0","id":request["id"],"result":version}));
    } else {
        send(
            json!({"jsonrpc":"2.0","id":request["id"],"error":{"code":-32601,"message":"legacy removed","data":{"version":version}}}),
        );
    }
}
/// Reads a version-specific discovery document without the SDK.
fn main() {
    let version = env!("FIXTURE_VERSION");
    let plugin = std::env::var("SAUSAGE_PLUGIN").unwrap();
    let mut lines = io::stdin().lock().lines();
    let request: Value = serde_json::from_str(&lines.next().unwrap().unwrap()).unwrap();
    let document: Value =
        serde_json::from_slice(&std::fs::read(format!("/state/{plugin}/{version}.json")).unwrap())
            .unwrap();
    let result = match request["method"].as_str().unwrap() {
        "deferred" => {
            deferred(&request, &plugin, &mut lines);
            return;
        }
        "legacy" => {
            legacy(&request, &document, version);
            return;
        }
        "rpc.discover" => {
            if document["x-test-wait"] == true {
                std::fs::write(format!("/state/{plugin}/discover-started"), "ready").unwrap();
                while !std::path::Path::new(&format!("/state/{plugin}/discover-release")).exists() {
                    std::thread::sleep(std::time::Duration::from_millis(1));
                }
            }
            document
        }
        "read" => {
            let text =
                std::fs::read_to_string(request["params"]["path"].as_str().unwrap()).unwrap();
            serde_json::from_str(&text).unwrap_or(json!(text))
        }
        "rpc.retired" => {
            std::fs::write(
                format!("/state/{plugin}/retired"),
                request["params"]["previous"].as_str().unwrap(),
            )
            .unwrap();
            json!({"retired":version})
        }
        "serve" | "hold" => {
            send(json!({"jsonrpc":"2.0","id":request["id"],"result":{"version":version}}));
            if request["method"] == "serve" {
                let exclusive = format!("/run/{plugin}-service");
                if std::fs::OpenOptions::new()
                    .write(true)
                    .create_new(true)
                    .open(&exclusive)
                    .is_err()
                {
                    std::fs::write(format!("/state/{plugin}/duplicate-service"), "duplicate")
                        .unwrap();
                }
                std::fs::write(format!("/state/{plugin}/service"), version).unwrap();
            }
            for _ in lines {}
            if request["method"] == "serve" {
                let _ = std::fs::remove_file(format!("/run/{plugin}-service"));
            }
            std::fs::write(format!("/state/{plugin}/ended-{version}"), "ended").unwrap();
            return;
        }
        _ => json!({"version":version}),
    };
    send(json!({"jsonrpc":"2.0","id":request["id"],"result":result}));
    if request["method"] == "rpc.discover" && result["x-test-linger"] == true {
        if result["x-test-stubborn"] == true {
            while !std::path::Path::new(&format!("/state/{plugin}/discovery-exit")).exists() {
                std::thread::sleep(std::time::Duration::from_millis(1));
            }
        } else {
            for _ in lines {}
        }
        std::fs::write(
            format!("/state/{plugin}/discovery-ended-{version}"),
            "ended",
        )
        .unwrap();
    }
}