// Code generators for template system
//
// This module provides various code generation capabilities for creating
// plugin files, documentation, tests, and configuration.

use super::config::*;
use super::templates::*;
use crate::error::{OptimError, Result};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::path::{Path, PathBuf};

/// Code generator types
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum GeneratorType {
    /// Core plugin code generator
    CorePlugin,
    /// Test file generator
    Tests,
    /// Documentation generator
    Documentation,
    /// Benchmark generator
    Benchmarks,
    /// Example generator
    Examples,
    /// CI/CD configuration generator
    CICD,
    /// Cargo.toml generator
    CargoConfig,
    /// README generator
    Readme,
    /// License generator
    License,
    /// GPU kernel generator
    GPUKernels,
    /// Distributed training generator
    Distributed,
    /// FFI bindings generator
    FFIBindings,
    /// Custom generator
    Custom(String),
}

/// Generated file information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GeneratedFile {
    /// File path relative to project root
    pub path: PathBuf,
    /// File content
    pub content: String,
    /// File type
    pub file_type: GeneratedFileType,
    /// Whether file should be executable
    pub executable: bool,
}

/// Types of generated files
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum GeneratedFileType {
    RustSource,
    CargoToml,
    Markdown,
    YAML,
    JSON,
    Shell,
    Python,
    Text,
    Binary,
}

/// Trait for code generators
pub trait CodeGenerator: std::fmt::Debug {
    /// Generate files for a plugin template
    fn generate(&self, template: &PluginTemplate, config: &TemplateGeneratorConfig) -> Result<Vec<GeneratedFile>>;

    /// Get the generator type
    fn generator_type(&self) -> GeneratorType;

    /// Validate that the generator can handle the template
    fn can_handle(&self, template: &PluginTemplate) -> bool;
}

/// Core plugin code generator
#[derive(Debug)]
pub struct CorePluginGenerator {
    /// Code templates
    templates: HashMap<String, String>,
}

impl CorePluginGenerator {
    pub fn new() -> Self {
        let mut templates = HashMap::new();

        // Basic optimizer template
        templates.insert("optimizer".to_string(), include_str!("templates/optimizer.rs").to_string());
        templates.insert("lib".to_string(), include_str!("templates/lib.rs").to_string());
        templates.insert("error".to_string(), include_str!("templates/error.rs").to_string());

        Self { templates }
    }

    fn generate_optimizer_code(&self, template: &PluginTemplate, config: &TemplateGeneratorConfig) -> Result<String> {
        let template_content = self.templates.get("optimizer")
            .ok_or_else(|| OptimError::InvalidConfig("Optimizer template not found".to_string()))?;

        // Simple template substitution (in a real implementation, use a proper template engine)
        let mut code = template_content.clone();
        code = code.replace("{{PLUGIN_NAME}}", &template.structure.name);
        code = code.replace("{{PLUGIN_DESCRIPTION}}", &template.structure.description);
        code = code.replace("{{AUTHOR}}", &template.metadata.author);

        Ok(code)
    }
}

impl CodeGenerator for CorePluginGenerator {
    fn generate(&self, template: &PluginTemplate, config: &TemplateGeneratorConfig) -> Result<Vec<GeneratedFile>> {
        let mut files = Vec::new();

        // Generate main optimizer code
        let optimizer_code = self.generate_optimizer_code(template, config)?;
        files.push(GeneratedFile {
            path: PathBuf::from("src/lib.rs"),
            content: optimizer_code,
            file_type: GeneratedFileType::RustSource,
            executable: false,
        });

        // Generate error handling module
        if let Some(error_template) = self.templates.get("error") {
            files.push(GeneratedFile {
                path: PathBuf::from("src/error.rs"),
                content: error_template.clone(),
                file_type: GeneratedFileType::RustSource,
                executable: false,
            });
        }

        Ok(files)
    }

    fn generator_type(&self) -> GeneratorType {
        GeneratorType::CorePlugin
    }

    fn can_handle(&self, _template: &PluginTemplate) -> bool {
        true // Core generator can handle any template
    }
}

/// Documentation generator
#[derive(Debug)]
pub struct DocumentationGenerator;

impl CodeGenerator for DocumentationGenerator {
    fn generate(&self, template: &PluginTemplate, config: &TemplateGeneratorConfig) -> Result<Vec<GeneratedFile>> {
        if !config.include_docs {
            return Ok(Vec::new());
        }

        let mut files = Vec::new();

        // Generate README.md
        let readme_content = self.generate_readme(template)?;
        files.push(GeneratedFile {
            path: PathBuf::from("README.md"),
            content: readme_content,
            file_type: GeneratedFileType::Markdown,
            executable: false,
        });

        // Generate API documentation
        let api_docs = self.generate_api_docs(template)?;
        files.push(GeneratedFile {
            path: PathBuf::from("docs/api.md"),
            content: api_docs,
            file_type: GeneratedFileType::Markdown,
            executable: false,
        });

        Ok(files)
    }

    fn generator_type(&self) -> GeneratorType {
        GeneratorType::Documentation
    }

    fn can_handle(&self, _template: &PluginTemplate) -> bool {
        true
    }
}

impl DocumentationGenerator {
    fn generate_readme(&self, template: &PluginTemplate) -> Result<String> {
        let content = format!(
            r#"# {}

{}

## Features

- Advanced optimization algorithm
- High-performance implementation
- GPU acceleration support
- Comprehensive testing

## Installation

Add this to your `Cargo.toml`:

```toml
[dependencies]
{} = "0.1.0"
```

## Usage

```rust
use {}::{{Optimizer}};

let optimizer = Optimizer::new();
// Use the optimizer...
```

## License

Licensed under {} license.
"#,
            template.structure.name,
            template.structure.description,
            template.structure.name.to_lowercase().replace(' ', "_"),
            template.structure.name.to_lowercase().replace(' ', "_"),
            template.metadata.license
        );

        Ok(content)
    }

    fn generate_api_docs(&self, template: &PluginTemplate) -> Result<String> {
        let content = format!(
            r#"# {} API Documentation

## Overview

{}

## Main Components

### Optimizer

The main optimizer implementation.

### Configuration

Configuration options for the optimizer.

## Examples

See the examples directory for usage examples.
"#,
            template.structure.name,
            template.structure.description
        );

        Ok(content)
    }
}

/// Test generator
#[derive(Debug)]
pub struct TestGenerator;

impl CodeGenerator for TestGenerator {
    fn generate(&self, template: &PluginTemplate, config: &TemplateGeneratorConfig) -> Result<Vec<GeneratedFile>> {
        let mut files = Vec::new();

        // Generate unit tests
        let test_content = self.generate_unit_tests(template)?;
        files.push(GeneratedFile {
            path: PathBuf::from("src/lib.rs").join("tests"),
            content: test_content,
            file_type: GeneratedFileType::RustSource,
            executable: false,
        });

        // Generate integration tests if requested
        if config.include_benchmarks {
            let bench_content = self.generate_benchmarks(template)?;
            files.push(GeneratedFile {
                path: PathBuf::from("benches/benchmark.rs"),
                content: bench_content,
                file_type: GeneratedFileType::RustSource,
                executable: false,
            });
        }

        Ok(files)
    }

    fn generator_type(&self) -> GeneratorType {
        GeneratorType::Tests
    }

    fn can_handle(&self, _template: &PluginTemplate) -> bool {
        true
    }
}

impl TestGenerator {
    fn generate_unit_tests(&self, template: &PluginTemplate) -> Result<String> {
        let content = format!(
            r#"#[cfg(test)]
mod tests {{
    use super::*;

    #[test]
    fn test_{}_creation() {{
        let optimizer = Optimizer::new();
        assert!(optimizer.is_ok());
    }}

    #[test]
    fn test_{}_optimization() {{
        // Add optimization tests here
    }}
}}
"#,
            template.structure.name.to_lowercase().replace(' ', "_"),
            template.structure.name.to_lowercase().replace(' ', "_")
        );

        Ok(content)
    }

    fn generate_benchmarks(&self, template: &PluginTemplate) -> Result<String> {
        let content = format!(
            r#"use criterion::{{black_box, criterion_group, criterion_main, Criterion}};
use {}::Optimizer;

fn benchmark_{}(c: &mut Criterion) {{
    c.bench_function("{}", |b| {{
        let optimizer = Optimizer::new().unwrap();
        b.iter(|| {{
            // Benchmark code here
            black_box(&optimizer);
        }});
    }});
}}

criterion_group!(benches, benchmark_{});
criterion_main!(benches);
"#,
            template.structure.name.to_lowercase().replace(' ', "_"),
            template.structure.name.to_lowercase().replace(' ', "_"),
            template.structure.name,
            template.structure.name.to_lowercase().replace(' ', "_")
        );

        Ok(content)
    }
}

impl Default for CorePluginGenerator {
    fn default() -> Self {
        Self::new()
    }
}