pub struct Strategy {}

use std::fs::{copy, create_dir_all};
use std::io::{Error, ErrorKind, Result};
use std::path::Path;

use crate::file_handler::{File, FileType, Strategy as FileHandlerStrategy};

impl Strategy {
    fn handle(source: &Path, destination: &Path, file: &File) -> Result<()> {
        let relative_path = file.path.strip_prefix(source).map_err(|_| {
            Error::new(
                ErrorKind::InvalidData,
                "Path was not part of source directory.",
            )
        })?;
        let complete_destination = destination.join(relative_path);
        match complete_destination.parent() {
            Some(destination_parent) => {
                create_dir_all(destination_parent)?;
                copy(&file.path, &complete_destination)?;
                Ok(())
            }
            None => Err(Error::new(
                ErrorKind::InvalidData,
                "Destination parent was not readable.",
            )),
        }
    }
}

impl FileHandlerStrategy for Strategy {
    fn is(&self, path: &Path) -> bool {
        !path.is_dir()
    }

    fn identify(&self) -> FileType {
        FileType::File
    }

    fn can_handle(&self, file_type: &FileType) -> bool {
        matches!(file_type, FileType::File)
    }

    fn handle_html(&self, source: &Path, destination: &Path, file: &File, _l: &str) -> Result<()> {
        Strategy::handle(source, destination, file)
    }

    fn handle_gemini(&self, source: &Path, destination: &Path, file: &File) -> Result<()> {
        Strategy::handle(source, destination, file)
    }
}

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

    use super::*;

    use test_utilities::*;

    #[test]
    fn identifies_regular_files() {
        let test_dir = setup_test_dir();
        create_test_file(&test_dir.join("image.png"), "");
        create_test_file(&test_dir.join("style.css"), "");
        let strategy = Strategy {};
        assert!(strategy.is(&test_dir.join("image.png")));
        assert!(strategy.is(&test_dir.join("style.css")));
    }

    #[test]
    fn rejects_directories() {
        let test_dir = setup_test_dir();
        let strategy = Strategy {};
        assert!(!strategy.is(&test_dir));
    }

    #[test]
    fn identifies_file_type() {
        let strategy = Strategy {};
        assert!(matches!(strategy.identify(), FileType::File));
    }

    #[test]
    fn handles_file_type() {
        let strategy = Strategy {};
        assert!(strategy.can_handle(&FileType::File));
    }

    #[test]
    fn rejects_non_file_types() {
        let strategy = Strategy {};
        assert!(!strategy.can_handle(&FileType::Layout));
        assert!(!strategy.can_handle(&FileType::Gemini));
        assert!(!strategy.can_handle(&FileType::Unknown));
    }

    #[test]
    fn copies_single_file() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let output_dir = test_dir.join("output");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_dir_all(&output_dir).expect("Could not create output test directory");
        create_test_file(&source_dir.join("image.png"), "A fish playing the banjo");

        let file = File {
            path: source_dir.join("image.png"),
            file_type: FileType::File,
        };

        assert!(Strategy::handle(&source_dir, &output_dir, &file).is_ok());

        let copied_path = &output_dir.join("image.png");
        assert!(copied_path.exists());

        // Verify file contents are identical
        let original = fs::read(&file.path).unwrap();
        let copied = fs::read(copied_path).unwrap();
        assert_eq!(original, copied);
    }

    #[test]
    fn copies_nested_file() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let output_dir = test_dir.join("output");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_dir_all(&output_dir).expect("Could not create output test directory");
        create_dir_all(source_dir.join("nested")).expect("Could not create source test directory");
        create_test_file(
            &source_dir.join("nested/style.css"),
            "* { margin: 0; padding: 0 }",
        );

        let file = File {
            path: source_dir.join("nested/style.css"),
            file_type: FileType::File,
        };

        assert!(Strategy::handle(&source_dir, &output_dir, &file).is_ok());

        let copied_path = output_dir.join("nested/style.css");
        assert!(copied_path.exists());

        // Verify file contents are identical
        let original = fs::read(&file.path).unwrap();
        let copied = fs::read(&copied_path).unwrap();
        assert_eq!(original, copied);
    }

    #[test]
    fn handle_html_copies_file() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let output_dir = test_dir.join("output");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_dir_all(&output_dir).expect("Could not create output test directory");
        create_test_file(&source_dir.join("image.png"), "A fish playing the banjo");
        let strategy = Strategy {};

        let file = File {
            path: source_dir.join("image.png"),
            file_type: FileType::File,
        };

        assert!(
            strategy
                .handle_html(&source_dir, &output_dir, &file, "unused layout")
                .is_ok()
        );

        let copied_path = &output_dir.join("image.png");
        assert!(copied_path.exists());

        // Verify file contents are identical
        let original = fs::read(&file.path).unwrap();
        let copied = fs::read(copied_path).unwrap();
        assert_eq!(original, copied);
    }

    #[test]
    fn handle_gemini_copies_file() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let output_dir = test_dir.join("output");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_dir_all(&output_dir).expect("Could not create output test directory");
        create_test_file(&source_dir.join("image.png"), "A fish playing the banjo");
        let strategy = Strategy {};

        let file = File {
            path: source_dir.join("image.png"),
            file_type: FileType::File,
        };

        assert!(
            strategy
                .handle_gemini(&source_dir, &output_dir, &file)
                .is_ok()
        );

        let copied_path = &output_dir.join("image.png");
        assert!(copied_path.exists());

        // Verify file contents are identical
        let original = fs::read(&file.path).unwrap();
        let copied = fs::read(copied_path).unwrap();
        assert_eq!(original, copied);
    }

    #[test]
    fn fails_if_file_is_not_part_of_source() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        let output_dir = test_dir.join("output");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_dir_all(&output_dir).expect("Could not create output test directory");
        create_test_file(&source_dir.join("image.png"), "A fish playing the banjo");

        let file = File {
            path: output_dir.join("image.png"),
            file_type: FileType::File,
        };

        assert!(Strategy::handle(&source_dir, &output_dir, &file).is_err());
    }

    #[test]
    fn fails_if_destination_parent_is_not_readable() {
        let test_dir = setup_test_dir();
        let source_dir = test_dir.join("source");
        create_dir_all(&source_dir).expect("Could not create source test directory");
        create_test_file(&source_dir.join("image.png"), "A fish playing the banjo");
        let output_dir = Path::new("");

        let file = File {
            path: source_dir.clone(),
            file_type: FileType::File,
        };

        assert!(Strategy::handle(&source_dir, output_dir, &file).is_err());
    }
}