-pub fn arrow_schema::Schema::all_fields(&self) -> alloc::vec::Vec<&arrow_schema::Field>

use regex::Regex;
use std::path::Path;
use crate::output::{Issue, Severity};
use crate::rules::Rule;

/// ARROW-007: Detect removed Schema::all_fields usage
/// 
/// Arrow 56.0 removed Schema::all_fields method. Suggest migration to
/// Schema::fields() or Schema::flattened_fields() depending on use case.
pub struct Arrow007Rule;

impl Rule for Arrow007Rule {
    fn rule_id(&self) -> &'static str {
        "ARROW-007"
    }

    fn check_rust_source(&self, file_path: &Path, content: &str) -> Result<Vec<Issue>, Box<dyn std::error::Error>> {
        let mut issues = Vec::new();
        
        // Pattern to match .all_fields() method calls
        let pattern = Regex::new(r"\.all_fields\s*\(\s*\)")?;
        
        for (line_num, line) in content.lines().enumerate() {
            if let Some(mat) = pattern.find(line) {
                let issue = Issue {
                    rule_id: self.rule_id().to_string(),
                    severity: Severity::Error,
                    message: "Schema::all_fields() was removed in Arrow 56.0".to_string(),
                    file_path: file_path.to_path_buf(),
                    line: line_num + 1,
                    column: mat.start() + 1,
                    suggestion: Some("Replace with schema.fields() for immediate fields or schema.flattened_fields() for recursive field collection. Note: flattened_fields() returns owned Fields, not references.".to_string()),
                    auto_fixable: false, // Requires semantic analysis
                    deprecated_since: Some("56.0.0".to_string()),
                    changelog_url: Some("https://github.com/apache/arrow-rs/blob/main/CHANGELOG.md#560".to_string()),
                    migration_guide_url: Some("https://arrow.apache.org/docs/rust/migration_guide.html#schema-all-fields-removal".to_string()),
                };
                issues.push(issue);
            }
        }
        
        Ok(issues)
    }

    fn check_cargo_toml(&self, _file_path: &Path, _content: &str) -> Result<Vec<Issue>, Box<dyn std::error::Error>> {
        Ok(Vec::new())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::path::PathBuf;

    #[test]
    fn test_detects_all_fields_usage() {
        let rule = Arrow007Rule;
        let content = r#"
use arrow_schema::Schema;

fn process_schema(schema: &Schema) {
    let fields = schema.all_fields();
    for field in fields {
        println\!("{}", field.name());
    }
}
"#;
        
        let issues = rule.check_rust_source(&PathBuf::from("test.rs"), content).unwrap();
        assert_eq\!(issues.len(), 1);
        assert_eq\!(issues[0].rule_id, "ARROW-007");
        assert\!(matches\!(issues[0].severity, Severity::Error));
        assert\!(issues[0].message.contains("all_fields() was removed"));
        assert\!(\!issues[0].auto_fixable);
    }

    #[test]
    fn test_no_issues_for_fields() {
        let rule = Arrow007Rule;
        let content = r#"
use arrow_schema::Schema;

fn process_schema(schema: &Schema) {
    let fields = schema.fields();
    for field in fields {
        println\!("{}", field.name());
    }
}
"#;
        
        let issues = rule.check_rust_source(&PathBuf::from("test.rs"), content).unwrap();
        assert_eq\!(issues.len(), 0);
    }
}