use std::fs;
use std::path::{Path, PathBuf};

use anyhow::Result;
use serde_json::{json, Value};

use crate::virtual_model::AdapterState;

pub(crate) fn infer_source_path(project: &str) -> String {
    if Path::new(project).join("src/lib.rs").is_file() {
        "src/lib.rs".to_owned()
    } else if Path::new(project).join("src/main.rs").is_file() {
        "src/main.rs".to_owned()
    } else if Path::new(project).join("src/build.rs").is_file() {
        "src/build.rs".to_owned()
    } else {
        "src/main.rs".to_owned()
    }
}

pub(crate) fn source_name(source_path: &str) -> &str {
    Path::new(source_path)
        .file_name()
        .and_then(|name| name.to_str())
        .unwrap_or(source_path)
}

pub(crate) fn stack_source_path(state: &AdapterState) -> String {
    normalized_source_path(&state.project, &state.source_path)
        .to_string_lossy()
        .into_owned()
}

pub(crate) fn source_paths_match(project: &str, configured: &str, requested: &str) -> bool {
    normalized_source_path(project, configured) == normalized_source_path(project, requested)
}

pub(crate) fn source_response(state: &AdapterState, request: &Value) -> Result<Value> {
    let source_path = request
        .get("arguments")
        .and_then(|arguments| arguments.get("source"))
        .and_then(|source| source.get("path"))
        .and_then(Value::as_str)
        .unwrap_or(&state.source_path);
    let content = fs::read_to_string(resolve_source_path(&state.project, source_path))?;
    Ok(json!({
        "content": content,
        "mimeType": "text/x-rustsrc",
    }))
}

pub(crate) fn resolve_source_path(project: &str, source_path: &str) -> PathBuf {
    let path = Path::new(source_path);
    if path.is_absolute() {
        path.to_path_buf()
    } else {
        Path::new(project).join(path)
    }
}

fn normalized_source_path(project: &str, source_path: &str) -> PathBuf {
    let resolved = resolve_source_path(project, source_path);
    let absolute = if resolved.is_absolute() {
        resolved
    } else {
        std::env::current_dir()
            .unwrap_or_else(|_| Path::new(".").to_path_buf())
            .join(resolved)
    };
    absolute.canonicalize().unwrap_or(absolute)
}