//! LSP diagnostic utility types.
use std::fmt;

use serde::{Deserialize, Serialize};

/// Describes the severity level of a [`Diagnostic`].
#[derive(Debug, Clone, Copy, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum Severity {
    Hint,
    Info,
    Warning,
    Error,
}

impl Default for Severity {
    fn default() -> Self {
        Self::Hint
    }
}

/// A range of `char`s within the text.
#[derive(Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq)]
pub struct Range {
    pub start: usize,
    pub end: usize,
}

impl Range {
    pub fn contains(self, pos: usize) -> bool {
        (self.start..self.end).contains(&pos)
    }
}

#[derive(Debug, Eq, Hash, PartialEq, Clone, Deserialize, Serialize)]
pub enum NumberOrString {
    Number(i32),
    String(String),
}

#[derive(Debug, Clone)]
pub enum DiagnosticTag {
    Unnecessary,
    Deprecated,
}

/// Corresponds to [`lsp_types::Diagnostic`](https://docs.rs/lsp-types/0.94.0/lsp_types/struct.Diagnostic.html)
#[derive(Debug, Clone)]
pub struct Diagnostic {
    pub range: Range,
    // whether this diagnostic ends at the end of(or inside) a word
    pub ends_at_word: bool,
    pub starts_at_word: bool,
    pub zero_width: bool,
    pub line: usize,
    pub message: String,
    pub severity: Option<Severity>,
    pub code: Option<NumberOrString>,
    pub provider: DiagnosticProvider,
    pub tags: Vec<DiagnosticTag>,
    pub source: Option<String>,
    pub data: Option<serde_json::Value>,
}

// TODO turn this into an enum + feature flag when lsp becomes optional
pub type DiagnosticProvider = LanguageServerId;

// while I would prefer having this in helix-lsp that necessitates a bunch of
// conversions I would rather not add. I think its fine since this just a very
// trivial newtype wrapper and we would need something similar once we define
// completions in core
slotmap::new_key_type! {
    pub struct LanguageServerId;
}

impl fmt::Display for LanguageServerId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{:?}", self.0)
    }
}

impl Diagnostic {
    #[inline]
    pub fn severity(&self) -> Severity {
        self.severity.unwrap_or(Severity::Warning)
    }
}