//! Diagnostic report types for el-lint.

#[derive(Debug, Clone, PartialEq)]
pub enum LintSeverity {
    Error,
    Warning,
    Info,
}

#[derive(Debug, Clone)]
pub struct LintDiagnostic {
    pub severity: LintSeverity,
    /// Rule code, e.g. "E001", "W002", "S001", "I001".
    pub code: String,
    pub message: String,
    /// Human-readable location hint, e.g. "function foo" or "file".
    pub location: String,
    pub suggestion: Option<String>,
}

#[derive(Debug)]
pub struct LintReport {
    pub diagnostics: Vec<LintDiagnostic>,
    pub file_path: Option<String>,
    pub source_lines: usize,
}

impl LintReport {
    pub fn has_errors(&self) -> bool {
        self.diagnostics
            .iter()
            .any(|d| d.severity == LintSeverity::Error)
    }

    pub fn error_count(&self) -> usize {
        self.diagnostics
            .iter()
            .filter(|d| d.severity == LintSeverity::Error)
            .count()
    }

    pub fn warning_count(&self) -> usize {
        self.diagnostics
            .iter()
            .filter(|d| d.severity == LintSeverity::Warning)
            .count()
    }

    /// Format as human-readable output (similar to rustc error output).
    pub fn display(&self) -> String {
        let mut out = String::new();
        for d in &self.diagnostics {
            let prefix = match d.severity {
                LintSeverity::Error => "error",
                LintSeverity::Warning => "warning",
                LintSeverity::Info => "info",
            };
            out.push_str(&format!("[{}] {}: {}\n", d.code, prefix, d.message));
            out.push_str(&format!("    --> {}\n", d.location));
            if let Some(suggestion) = &d.suggestion {
                out.push_str(&format!("    help: {}\n", suggestion));
            }
            out.push('\n');
        }
        if self.diagnostics.is_empty() {
            out.push_str("No issues found.\n");
        }
        out
    }

    /// Format as JSON for editor integration.
    pub fn to_json(&self) -> String {
        let items: Vec<serde_json::Value> = self
            .diagnostics
            .iter()
            .map(|d| {
                serde_json::json!({
                    "severity": match d.severity {
                        LintSeverity::Error => "error",
                        LintSeverity::Warning => "warning",
                        LintSeverity::Info => "info",
                    },
                    "code": d.code,
                    "message": d.message,
                    "location": d.location,
                    "suggestion": d.suggestion,
                })
            })
            .collect();
        serde_json::to_string_pretty(&items).unwrap()
    }
}