use crate::model::file::MediaFile;
use crate::utils::{Result, ScannerError};
use std::fs;
use std::path::Path;
use tracing::{debug, warn};

/// Scans a directory for media files and folders
pub struct FileScanner {
    extensions: Vec<String>,
}

impl FileScanner {
    /// Create a new FileScanner with default media extensions
    pub fn new() -> Self {
        Self {
            extensions: vec![
                ".mp4".to_string(),
                ".mkv".to_string(),
                ".avi".to_string(),
                ".mov".to_string(),
                ".flv".to_string(),
                ".webm".to_string(),
            ],
        }
    }

    /// Check if a file has a media extension
    pub fn is_media_file(&self, path: &Path) -> bool {
        path.extension()
            .and_then(|ext| ext.to_str())
            .map(|ext| {
                self.extensions
                    .contains(&format!(".{}", ext.to_lowercase()))
            })
            .unwrap_or(false)
    }

    /// Scan a directory for media files and folders (non-recursive)
    /// This version doesn't require a callback and can be used in async contexts
    /// 
    /// This method is designed to be Send-safe for use with async/await
    pub async fn scan_directory_simple(&self, path: &Path) -> Result<Vec<MediaFile>> {
        // Inline the scan logic directly to avoid the Send issue with callbacks
        let mut items = Vec::new();
        let mut file_count = 0;

        // First, collect all entries to get a total count
        let mut total_files = 0;
        let mut dir_count = 0;

        // Read directory entries
        let entries = match fs::read_dir(path) {
            Ok(e) => e,
            Err(e) => {
                if e.kind() == std::io::ErrorKind::PermissionDenied {
                    warn!("Permission denied reading directory: {:?}", path);
                    return Ok(Vec::new());
                }
                return Err(ScannerError::Io(e).into());
            }
        };

        // First pass: count total files and directories
        for entry in entries.flatten() {
            if let Ok(file_type) = entry.file_type() {
                let file_name = entry.file_name();
                let file_name_str = file_name.to_string_lossy();

                if file_name_str.starts_with('.') {
                    continue;
                }

                if file_type.is_dir() {
                    dir_count += 1;
                } else if file_type.is_file() {
                    total_files += 1;
                }
            }
        }

        debug!(
            "Directory scan: {} folders, {} media files to process",
            dir_count, total_files
        );

        // Second pass: process entries (no callback needed)
        let entries = match fs::read_dir(path) {
            Ok(e) => e,
            Err(e) => {
                if e.kind() == std::io::ErrorKind::PermissionDenied {
                    warn!("Permission denied reading directory: {:?}", path);
                    return Ok(Vec::new());
                }
                return Err(ScannerError::Io(e).into());
            }
        };

        for entry in entries.flatten() {
            let file_type = match entry.file_type() {
                Ok(t) => t,
                Err(e) => {
                    warn!("Failed to get file type for {:?}: {}", entry.path(), e);
                    continue;
                }
            };

            let file_name = entry.file_name();
            let file_name_str = file_name.to_string_lossy();

            // Skip hidden files
            if file_name_str.starts_with('.') {
                continue;
            }

            if file_type.is_dir() {
                // Handle directory
                let metadata = match entry.metadata() {
                    Ok(m) => m,
                    Err(e) => {
                        warn!(
                            "Failed to get metadata for directory {:?}: {}",
                            entry.path(),
                            e
                        );
                        continue;
                    }
                };

                items.push(MediaFile {
                    path: entry.path(),
                    name: file_name.to_string_lossy().to_string(),
                    size: 0,
                    modified: metadata
                        .modified()
                        .map(|m| {
                            // Convert SystemTime to DateTime<Utc>
                            use chrono::DateTime;
                            DateTime::from(m)
                        })
                        .unwrap_or_else(|_| chrono::Utc::now()),
                    duration: "".to_string(),
                    quality: "".to_string(),
                    fps: "".to_string(),
                    is_folder: true,
                    is_problematic: false,
                    tags: Vec::new(),
                });
            } else if file_type.is_file() && self.is_media_file(&entry.path()) {
                // Handle media file
                file_count += 1;

                // Extract metadata
                let mut file = MediaFile::from_path(entry.path());

                // Update size and modified time
                match entry.metadata() {
                    Ok(metadata) => {
                        file.size = metadata.len();
                        file.modified = metadata
                            .modified()
                            .map(|m| {
                                let sys_time: chrono::DateTime<chrono::Utc> = m.into();
                                sys_time
                            })
                            .unwrap_or_else(|_| chrono::Utc::now());
                    }
                    Err(e) => {
                        warn!("Failed to get metadata for {:?}: {}", entry.path(), e);
                        file.is_problematic = true;
                    }
                }

                items.push(file);
            }
        }

        debug!("Directory scan complete: {} items found", items.len());

        // Sort: folders first, then files
        items.sort_by(|a, b| {
            if a.is_folder && !b.is_folder {
                std::cmp::Ordering::Less
            } else if !a.is_folder && b.is_folder {
                std::cmp::Ordering::Greater
            } else {
                a.name.cmp(&b.name)
            }
        });

        Ok(items)
    }

    /// Scan a directory for media files and folders (non-recursive)
    ///
    /// # Arguments
    /// * `path` - The directory path to scan
    /// * `progress_callback` - Optional mutable callback for progress updates
    ///   Signature: `FnMut(usize, usize, &str)` where:
    ///   - First usize: current file count
    ///   - Second usize: total files to process
    ///   - &str: current file name
    #[allow(clippy::type_complexity)]
    pub async fn scan_directory(
        &self,
        path: &Path,
        mut progress_callback: Option<&mut dyn FnMut(usize, usize, &str)>,
    ) -> Result<Vec<MediaFile>> {
        let mut items = Vec::new();
        let mut file_count = 0;

        // First, collect all entries to get a total count
        let mut total_files = 0;
        let mut dir_count = 0;

        // Read directory entries
        let entries = match fs::read_dir(path) {
            Ok(e) => e,
            Err(e) => {
                if e.kind() == std::io::ErrorKind::PermissionDenied {
                    warn!("Permission denied reading directory: {:?}", path);
                    return Ok(Vec::new());
                }
                return Err(ScannerError::Io(e).into());
            }
        };

        // First pass: count total files and directories
        for entry in entries.flatten() {
            if let Ok(file_type) = entry.file_type() {
                let file_name = entry.file_name();
                let file_name_str = file_name.to_string_lossy();

                if file_name_str.starts_with('.') {
                    continue;
                }

                if file_type.is_dir() {
                    dir_count += 1;
                } else if file_type.is_file() {
                    total_files += 1;
                }
            }
        }

        debug!(
            "Directory scan: {} folders, {} media files to process",
            dir_count, total_files
        );

        // Second pass: process entries
        let entries = match fs::read_dir(path) {
            Ok(e) => e,
            Err(e) => {
                if e.kind() == std::io::ErrorKind::PermissionDenied {
                    warn!("Permission denied reading directory: {:?}", path);
                    return Ok(Vec::new());
                }
                return Err(ScannerError::Io(e).into());
            }
        };

        for entry in entries.flatten() {
            let file_type = match entry.file_type() {
                Ok(t) => t,
                Err(e) => {
                    warn!("Failed to get file type for {:?}: {}", entry.path(), e);
                    continue;
                }
            };

            let file_name = entry.file_name();
            let file_name_str = file_name.to_string_lossy();

            // Skip hidden files
            if file_name_str.starts_with('.') {
                continue;
            }

            if file_type.is_dir() {
                // Handle directory
                let metadata = match entry.metadata() {
                    Ok(m) => m,
                    Err(e) => {
                        warn!(
                            "Failed to get metadata for directory {:?}: {}",
                            entry.path(),
                            e
                        );
                        continue;
                    }
                };

                items.push(MediaFile {
                    path: entry.path(),
                    name: file_name.to_string_lossy().to_string(),
                    size: 0,
                    modified: metadata
                        .modified()
                        .map(|m| {
                            // Convert SystemTime to DateTime<Utc>
                            use chrono::DateTime;
                            DateTime::from(m)
                        })
                        .unwrap_or_else(|_| chrono::Utc::now()),
                    duration: "".to_string(),
                    quality: "".to_string(),
                    fps: "".to_string(),
                    is_folder: true,
                    is_problematic: false,
                    tags: Vec::new(),
                });
            } else if file_type.is_file() && self.is_media_file(&entry.path()) {
                // Handle media file
                file_count += 1;

                if let Some(callback) = &mut progress_callback {
                    callback(file_count, total_files, &file_name_str);
                }

                // Extract metadata
                let mut file = MediaFile::from_path(entry.path());

                // Update size and modified time
                match entry.metadata() {
                    Ok(metadata) => {
                        file.size = metadata.len();
                        file.modified = metadata
                            .modified()
                            .map(|m| {
                                let sys_time: chrono::DateTime<chrono::Utc> = m.into();
                                sys_time
                            })
                            .unwrap_or_else(|_| chrono::Utc::now());
                    }
                    Err(e) => {
                        warn!("Failed to get metadata for {:?}: {}", entry.path(), e);
                        file.is_problematic = true;
                    }
                }

                items.push(file);
            }
        }

        debug!("Directory scan complete: {} items found", items.len());

        // Sort: folders first, then files
        items.sort_by(|a, b| {
            if a.is_folder && !b.is_folder {
                std::cmp::Ordering::Less
            } else if !a.is_folder && b.is_folder {
                std::cmp::Ordering::Greater
            } else {
                a.name.cmp(&b.name)
            }
        });

        Ok(items)
    }
}

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

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs::{self, File};
    use tempfile::tempdir;

    #[test]
    fn test_is_media_file() {
        let scanner = FileScanner::new();

        assert!(scanner.is_media_file(Path::new("/test/video.mp4")));
        assert!(scanner.is_media_file(Path::new("/test/video.MP4")));
        assert!(scanner.is_media_file(Path::new("/test/video.mkv")));
        assert!(scanner.is_media_file(Path::new("/test/video.avi")));
        assert!(scanner.is_media_file(Path::new("/test/video.mov")));
        assert!(scanner.is_media_file(Path::new("/test/video.flv")));
        assert!(scanner.is_media_file(Path::new("/test/video.webm")));

        assert!(!scanner.is_media_file(Path::new("/test/video.txt")));
        assert!(!scanner.is_media_file(Path::new("/test/video.jpg")));
        assert!(!scanner.is_media_file(Path::new("/test/folder")));
    }

    #[tokio::test]
    async fn test_scan_directory_empty() {
        let scanner = FileScanner::new();
        let temp_dir = tempdir().unwrap();
        let result: Result<Vec<MediaFile>> = scanner.scan_directory(temp_dir.path(), None).await;

        assert!(result.is_ok());
        assert_eq!(result.unwrap().len(), 0);
    }

    #[tokio::test]
    async fn test_scan_directory_with_media_files() {
        let scanner = FileScanner::new();
        let temp_dir = tempdir().unwrap();

        // Create some test media files
        let media_files = vec!["video1.mp4", "video2.mkv", "video3.avi"];
        for filename in &media_files {
            let path = temp_dir.path().join(filename);
            File::create(&path).unwrap();
        }

        let result: Result<Vec<MediaFile>> = scanner.scan_directory(temp_dir.path(), None).await;
        let result = result.unwrap();
        assert_eq!(result.len(), 3);

        // Verify files are sorted
        assert_eq!(result[0].name, "video1.mp4");
        assert_eq!(result[1].name, "video2.mkv");
        assert_eq!(result[2].name, "video3.avi");
    }

    #[tokio::test]
    async fn test_scan_directory_with_folders() {
        let scanner = FileScanner::new();
        let temp_dir = tempdir().unwrap();

        // Create folders
        fs::create_dir(temp_dir.path().join("folder1")).unwrap();
        fs::create_dir(temp_dir.path().join("folder2")).unwrap();

        let result: Result<Vec<MediaFile>> = scanner.scan_directory(temp_dir.path(), None).await;
        let result = result.unwrap();

        // Folders should be first
        assert_eq!(result.len(), 2);
        assert!(result[0].is_folder);
        assert!(result[1].is_folder);
    }

    #[tokio::test]
    async fn test_scan_directory_with_mixed_content() {
        let scanner = FileScanner::new();
        let temp_dir = tempdir().unwrap();

        // Create folders
        fs::create_dir(temp_dir.path().join("movies")).unwrap();
        fs::create_dir(temp_dir.path().join("tv")).unwrap();

        // Create media files
        let media_files = vec!["movie1.mp4", "movie2.mkv"];
        for filename in &media_files {
            let path = temp_dir.path().join(filename);
            File::create(&path).unwrap();
        }

        let result: Result<Vec<MediaFile>> = scanner.scan_directory(temp_dir.path(), None).await;
        let result = result.unwrap();

        // Should have 4 items: 2 folders + 2 media files
        assert_eq!(result.len(), 4);

        // Folders should come first
        assert!(result[0].is_folder);
        assert!(result[1].is_folder);
        assert!(!result[2].is_folder);
        assert!(!result[3].is_folder);
    }

    #[tokio::test]
    async fn test_scan_directory_with_progress_callback() {
        let scanner = FileScanner::new();
        let temp_dir = tempdir().unwrap();

        // Create media files
        let media_files = vec!["video1.mp4", "video2.mkv", "video3.avi"];
        for filename in &media_files {
            let path = temp_dir.path().join(filename);
            File::create(&path).unwrap();
        }

        let mut progress_count = 0;
        let mut progress_data = Vec::new();
        let mut callback = |current: usize, total: usize, filename: &str| {
            progress_count += 1;
            progress_data.push((current, total, filename.to_string()));
        };

        let result: Result<Vec<MediaFile>> = scanner
            .scan_directory(temp_dir.path(), Some(&mut callback))
            .await;
        let result = result.unwrap();

        assert_eq!(progress_count, 3);
        assert_eq!(result.len(), 3);
    }

    #[tokio::test]
    async fn test_scan_directory_with_hidden_files() {
        let scanner = FileScanner::new();
        let temp_dir = tempdir().unwrap();

        // Create media files (including hidden)
        let media_files = vec![".hidden.mp4", "visible.mkv"];
        for filename in &media_files {
            let path = temp_dir.path().join(filename);
            File::create(&path).unwrap();
        }

        let result: Result<Vec<MediaFile>> = scanner.scan_directory(temp_dir.path(), None).await;
        let result = result.unwrap();

        // Hidden files should be skipped
        assert_eq!(result.len(), 1);
        assert_eq!(result[0].name, "visible.mkv");
    }

    #[tokio::test]
    async fn test_scan_directory_nonexistent() {
        let scanner = FileScanner::new();
        let result: Result<Vec<MediaFile>> = scanner
            .scan_directory(Path::new("/nonexistent/path"), None)
            .await;

        // Should return an error for non-existent directory
        assert!(result.is_err());
    }
}