mod file_strategies;

use file_strategies::file::Strategy as FileStrategy;
use file_strategies::gemini::Strategy as GeminiStrategy;
use file_strategies::layout::Strategy as LayoutStrategy;

use std::fs::read_to_string;
use std::io::{Error, ErrorKind, Result};
use std::path::{Path, PathBuf};

pub struct FileHandler {
    pub strategies: Vec<Box<dyn Strategy>>,
    pub layout: Option<String>,
}

impl Default for FileHandler {
    fn default() -> FileHandler {
        FileHandler {
            strategies: vec![
                Box::new(GeminiStrategy {}),
                Box::new(LayoutStrategy {}),
                Box::new(FileStrategy {}),
            ],
            layout: None,
        }
    }
}

impl FileHandler {
    pub fn identify(&self, path: &Path) -> FileType {
        for strategy in &self.strategies {
            if strategy.is(path) {
                return strategy.identify();
            }
        }
        FileType::Unknown
    }

    pub fn get_layout(&mut self, files: &[File]) -> Result<()> {
        for file in files {
            if file.file_type == FileType::Layout {
                let layout_text = read_to_string(&file.path)?;
                self.layout = Some(layout_text);
                return Ok(());
            }
        }
        Err(Error::new(
            ErrorKind::NotFound,
            "No layout found. Please ensure there's a _layout.html file at the root",
        ))
    }

    pub fn handle_all(
        &self,
        source: &Path,
        html_destination: &Path,
        gemini_destination: &Path,
        files: &[File],
    ) -> Result<()> {
        for file in files {
            self.handle(source, html_destination, gemini_destination, file)?;
        }
        Ok(())
    }

    pub fn handle(
        &self,
        source: &Path,
        html_destination: &Path,
        gemini_destination: &Path,
        file: &File,
    ) -> Result<()> {
        match self
            .strategies
            .iter()
            .find(|s| s.can_handle(&file.file_type))
        {
            Some(strategy) => {
                let layout = self.layout.as_ref().ok_or_else(|| {
                    Error::new(
                        ErrorKind::NotFound,
                        "Layout should be initialized before handling files",
                    )
                })?;
                strategy.handle_html(source, html_destination, file, layout)?;
                strategy.handle_gemini(source, gemini_destination, file)?;
                Ok(())
            }

            // We silently ignore files we can't process.
            None => Ok(()),
        }
    }
}

pub trait Strategy {
    fn is(&self, path: &Path) -> bool;
    fn identify(&self) -> FileType;
    fn can_handle(&self, file_type: &FileType) -> bool;
    fn handle_html(
        &self,
        source: &Path,
        destination: &Path,
        file: &File,
        layout: &str,
    ) -> Result<()>;
    fn handle_gemini(&self, source: &Path, destination: &Path, file: &File) -> Result<()>;
}

#[derive(Debug, Clone, PartialEq)]
pub enum FileType {
    Gemini,
    File,
    Layout,
    Unknown,
}

#[derive(PartialEq, Debug)]
pub struct File {
    pub path: PathBuf,
    pub file_type: FileType,
}

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

    use super::*;

    use test_utilities::*;

    fn create_test_internal_file(path: &str, file_type: FileType) -> File {
        File {
            path: PathBuf::from(path),
            file_type,
        }
    }

    #[test]
    fn test_identify_gemini_file() {
        let handler = FileHandler::default();
        let path = PathBuf::from("test.gmi");
        assert!(matches!(handler.identify(&path), FileType::Gemini));
    }

    #[test]
    fn test_identify_layout_file() {
        let handler = FileHandler::default();
        let path = PathBuf::from("_layout.html");
        assert!(matches!(handler.identify(&path), FileType::Layout));
    }

    #[test]
    fn test_identify_regular_file() {
        let handler = FileHandler::default();
        let path = PathBuf::from("regular.html");
        assert!(matches!(handler.identify(&path), FileType::File));
    }

    #[test]
    fn test_identify_unknown_file() {
        let handler = FileHandler::default();
        let path = PathBuf::from("tests");
        assert!(matches!(handler.identify(&path), FileType::Unknown));
    }

    #[test]
    fn test_get_layout_success() {
        let test_dir = setup_test_dir();
        let layout_path = test_dir.join("_layout.html");
        create_test_file(&layout_path, "");

        let mut handler = FileHandler::default();
        let files = vec![
            create_test_internal_file("test.gmi", FileType::Gemini),
            create_test_internal_file(
                layout_path.to_str().expect("Could not encode layout"),
                FileType::Layout,
            ),
            create_test_internal_file("regular.html", FileType::File),
        ];

        assert!(handler.get_layout(&files).is_ok());
    }

    #[test]
    fn test_get_layout_failure() {
        let mut handler = FileHandler::default();
        let files = vec![
            create_test_internal_file("test.gmi", FileType::Gemini),
            create_test_internal_file("regular.html", FileType::File),
        ];

        assert!(handler.get_layout(&files).is_err());
    }

    // Mock strategy for testing
    struct MockStrategy {
        is_match: bool,
        file_type: FileType,
    }

    impl Strategy for MockStrategy {
        fn is(&self, _path: &Path) -> bool {
            self.is_match
        }

        fn identify(&self) -> FileType {
            self.file_type.clone()
        }

        fn can_handle(&self, file_type: &FileType) -> bool {
            &self.file_type == file_type
        }

        fn handle_html(
            &self,
            _source: &Path,
            _destination: &Path,
            _file: &File,
            _layout: &str,
        ) -> Result<()> {
            Ok(())
        }
        fn handle_gemini(&self, _source: &Path, _destination: &Path, _file: &File) -> Result<()> {
            Ok(())
        }
    }

    // Mock strategy for testing
    struct ErroringMockStrategy {
        is_match: bool,
        file_type: FileType,
    }

    impl Strategy for ErroringMockStrategy {
        fn is(&self, _path: &Path) -> bool {
            self.is_match
        }

        fn identify(&self) -> FileType {
            self.file_type.clone()
        }

        fn can_handle(&self, file_type: &FileType) -> bool {
            &self.file_type == file_type
        }

        fn handle_html(
            &self,
            _source: &Path,
            _destination: &Path,
            _file: &File,
            _layout: &str,
        ) -> Result<()> {
            Err(Error::new(
                ErrorKind::Other,
                "Forced to fail by my cruel author.",
            ))
        }
        fn handle_gemini(&self, _source: &Path, _destination: &Path, _file: &File) -> Result<()> {
            Err(Error::new(
                ErrorKind::Other,
                "Forced to fail by my benevolent author.",
            ))
        }
    }

    #[test]
    fn test_custom_strategy() {
        let mock_strategy = MockStrategy {
            is_match: true,
            file_type: FileType::Gemini,
        };

        let handler = FileHandler {
            strategies: vec![Box::new(mock_strategy)],
            layout: Some("None".to_string()),
        };

        let path = PathBuf::from("test.whatever");
        let file = File {
            path: path.clone(),
            file_type: FileType::Gemini,
        };
        assert!(matches!(handler.identify(&path), FileType::Gemini));
        assert!(handler.handle(&path, &path, &path, &file).is_ok());
    }

    #[test]
    fn test_failure_propagates_in_handler() {
        let mock_strategy = ErroringMockStrategy {
            is_match: true,
            file_type: FileType::Gemini,
        };

        let handler = FileHandler {
            strategies: vec![Box::new(mock_strategy)],
            layout: Some("None".to_string()),
        };

        let path = PathBuf::from("test.whatever");
        let file = File {
            path: path.clone(),
            file_type: FileType::Gemini,
        };
        assert!(matches!(handler.identify(&path), FileType::Gemini));
        assert!(handler.handle(&path, &path, &path, &file).is_err());
    }

    #[test]
    fn silently_ignore_unhandleable_files() {
        let mock_strategy = MockStrategy {
            is_match: false,
            file_type: FileType::Gemini,
        };

        let handler = FileHandler {
            strategies: vec![Box::new(mock_strategy)],
            layout: Some("None".to_string()),
        };

        let path = PathBuf::from("test.whatever");
        let file = File {
            path: path.clone(),
            file_type: FileType::Layout,
        };
        assert!(handler.handle(&path, &path, &path, &file).is_ok());
    }

    #[test]
    fn test_handle_all_empty_files() {
        let handler = FileHandler::default();
        let files: Vec<File> = vec![];

        // Should not panic with empty vector
        assert!(
            handler
                .handle_all(
                    &PathBuf::from("source"),
                    &PathBuf::from("output_html"),
                    &PathBuf::from("output_gemini"),
                    &files,
                )
                .is_ok()
        );
    }

    #[test]
    fn test_handle_with_layout() {
        let handler = FileHandler {
            layout: Some("test layout".to_string()),
            ..Default::default()
        };

        let test_dir = setup_test_dir();
        create_dir_all(test_dir.join("output_html"))
            .expect("Could not create output html test directory");
        create_dir_all(test_dir.join("output_gemini"))
            .expect("Could not create output gemini test directory");
        let test_path = test_dir.join("test.gmi");
        create_test_file(&test_path, "");
        let file = create_test_internal_file(
            test_path
                .to_str()
                .expect("Could not encode gemini test file"),
            FileType::Gemini,
        );

        // Should not panic with valid layout
        assert!(
            handler
                .handle(
                    &test_dir,
                    &test_dir.join("output_html"),
                    &test_dir.join("output_gemini"),
                    &file,
                )
                .is_ok()
        );
    }

    #[test]
    fn test_handle_without_layout() {
        let handler = FileHandler::default();
        let file = create_test_internal_file("test.gmi", FileType::Gemini);

        assert!(
            handler
                .handle(
                    &PathBuf::from("source"),
                    &PathBuf::from("output_html"),
                    &PathBuf::from("output_gemini"),
                    &file,
                )
                .is_err()
        );
    }

    #[test]
    fn test_slice_handling() {
        let test_dir = setup_test_dir();
        let layout_path = test_dir.join("_layout.html");
        create_test_file(&layout_path, "");
        create_test_file(&test_dir.join("test1.gmi"), "");
        create_test_file(&test_dir.join("test2.gmi"), "");
        create_test_file(&test_dir.join("test3.gmi"), "");
        create_dir_all(test_dir.join("output_html"))
            .expect("Could not create output html test directory");
        create_dir_all(test_dir.join("output_gemini"))
            .expect("Could not create output gemini test directory");

        let mut handler = FileHandler::default();
        let files = [
            create_test_internal_file(
                test_dir
                    .join("test1.gmi")
                    .to_str()
                    .expect("Could not encode test1"),
                FileType::Gemini,
            ),
            create_test_internal_file(
                layout_path.to_str().expect("Could not encode layout"),
                FileType::Layout,
            ),
            create_test_internal_file(
                test_dir
                    .join("test2.gmi")
                    .to_str()
                    .expect("Could not encode test2"),
                FileType::Gemini,
            ),
            create_test_internal_file(
                test_dir
                    .join("test3.gmi")
                    .to_str()
                    .expect("Could not encode test3"),
                FileType::Gemini,
            ),
        ];

        let _ = handler.get_layout(&files[1..]);

        // Test with slice
        assert!(
            handler
                .handle_all(
                    &test_dir,
                    &test_dir.join("output_html"),
                    &test_dir.join("output_gemini"),
                    &files[1..], // Test with slice of last three elements
                )
                .is_ok()
        );
    }
}