//! Test generator for comprehensive test coverage

use super::{CreateSpec, QualityProfile};
use anyhow::Result;

/// Test generator for comprehensive test coverage
pub struct TestGenerator {
    pub(crate) profile: QualityProfile,
}

impl TestGenerator {
    #[must_use]
    /// Create a new instance.
    pub fn new(profile: QualityProfile) -> Self {
        Self { profile }
    }

    /// Generate comprehensive tests for a function
    pub fn generate_for_function(&self, _code: &str, spec: &CreateSpec) -> Result<String> {
        let mut tests = String::new();

        tests.push_str("#[cfg(test)]\nmod tests {\n    use super::*;\n\n");

        // Generate basic unit test
        tests.push_str(&format!(
            "    #[test]\n    fn test_{}_basic() {{\n",
            spec.name
        ));
        tests.push_str("        // Test basic functionality\n");
        tests.push_str(&format!("        let result = {}(", spec.name));

        for (i, param) in spec.inputs.iter().enumerate() {
            if i > 0 {
                tests.push_str(", ");
            }
            tests.push_str(&self.generate_test_value(&param.param_type));
        }

        tests.push_str(");\n");
        tests.push_str("        assert!(result.is_ok());\n");
        tests.push_str("    }\n\n");

        // Generate error test
        tests.push_str(&format!(
            "    #[test]\n    fn test_{}_edge_cases() {{\n",
            spec.name
        ));
        tests.push_str("        // Test edge cases and error conditions\n");
        tests.push_str("        // Add specific edge case tests here\n");
        tests.push_str("    }\n\n");

        // Generate property test if required
        if self.profile.thresholds.require_property_tests {
            tests.push_str("    use proptest::prelude::*;\n\n");
            tests.push_str(&format!(
                "    proptest! {{\n        #[test]\n        fn prop_{}_always_valid(\n",
                spec.name
            ));

            for param in &spec.inputs {
                tests.push_str(&format!(
                    "            {} in any::<{}>(),\n",
                    param.name, param.param_type
                ));
            }

            tests.push_str("        ) {\n");
            tests.push_str(&format!("            let result = {}(", spec.name));

            for (i, param) in spec.inputs.iter().enumerate() {
                if i > 0 {
                    tests.push_str(", ");
                }
                tests.push_str(&param.name);
            }

            tests.push_str(");\n");
            tests.push_str(
                "            // Property: function should handle all inputs gracefully\n",
            );
            tests.push_str("            // Add property assertions here\n");
            tests.push_str("        }\n    }\n\n");
        }

        tests.push_str("}\n");

        Ok(tests)
    }

    /// Generate test value for parameter type
    pub fn generate_test_value(&self, param_type: &str) -> String {
        match param_type {
            "u32" | "i32" => "42".to_string(),
            "f32" | "f64" => "3.14".to_string(),
            "String" => "\"test\".to_string()".to_string(),
            "&str" => "\"test\"".to_string(),
            "bool" => "true".to_string(),
            _ => "Default::default()".to_string(),
        }
    }

    /// Generate tests for any code
    pub fn generate_tests(&self, _code: &str) -> Result<String> {
        let mut tests = String::new();

        tests.push_str("#[cfg(test)]\nmod tests {\n    use super::*;\n\n");
        tests.push_str("    #[test]\n    fn test_generated_code() {\n");
        tests.push_str("        // Auto-generated test for code quality\n");
        tests.push_str("        assert!(true); // Placeholder\n");
        tests.push_str("    }\n");

        // Add property tests if required
        if self.profile.thresholds.require_property_tests {
            tests.push_str("\n    #[cfg(feature = \"property-testing\")]\n");
            tests.push_str("    mod property_tests {\n");
            tests.push_str("        use super::*;\n");
            tests.push_str("        use proptest::prelude::*;\n\n");
            tests.push_str("        proptest! {\n");
            tests.push_str("            #[test]\n");
            tests.push_str("            fn property_test_code(input in any::<u32>()) {\n");
            tests.push_str("                // Property-based test\n");
            tests.push_str("                assert!(input == input);\n");
            tests.push_str("            }\n");
            tests.push_str("        }\n");
            tests.push_str("    }\n");
        }

        tests.push_str("}\n");
        Ok(tests)
    }
}
