//! macOS Unicode Private Range Mapping for SMB
//!
//! macOS SMB client maps NTFS illegal characters to Unicode private range.
//! Reference: Samba vfs_catia.c and vfs_fruit.c encoding handling
//!
//! Full mapping table (Samba catia standard):
//!   U+F001 → /    (0x2F)
//!   U+F002 → :    (0x3A)
//!   U+F003 → *    (0x2A)
//!   U+F004 → ?    (0x3F)
//!   U+F005 → "    (0x22)
//!   U+F006 → <    (0x3C)
//!   U+F007 → >    (0x3E)
//!   U+F008 → |    (0x7C)
//!   U+F009 → \    (0x5C)
//!   U+F02A → :    (0x3A)  — macOS Finder uses this for colon

pub const FRUIT_ENC_NATIVE: bool = true;
pub const FRUIT_ENC_PRIVATE: bool = false;

// Apple private range code points (vfs_catia mapping)
const APPLE_SLASH: u16 = 0xF001;
const APPLE_COLON_ALT: u16 = 0xF002;
const APPLE_ASTERISK: u16 = 0xF003;
const APPLE_QUESTION: u16 = 0xF004;
const APPLE_QUOTE: u16 = 0xF005;
const APPLE_LESS_THAN: u16 = 0xF006;
const APPLE_GREATER_THAN: u16 = 0xF007;
const APPLE_PIPE: u16 = 0xF008;
const APPLE_BACKSLASH: u16 = 0xF009;
const APPLE_COLON: u16 = 0xF02A;  // macOS Finder specific

const ASCII_SLASH: u16 = '/' as u16;
const ASCII_COLON: u16 = ':' as u16;
const ASCII_ASTERISK: u16 = '*' as u16;
const ASCII_QUESTION: u16 = '?' as u16;
const ASCII_QUOTE: u16 = '"' as u16;
const ASCII_LESS_THAN: u16 = '<' as u16;
const ASCII_GREATER_THAN: u16 = '>' as u16;
const ASCII_PIPE: u16 = '|' as u16;
const ASCII_BACKSLASH: u16 = '\\' as u16;

/// Check if a UTF-16 code unit is in the macOS private range.
pub fn is_private_range_char(u: u16) -> bool {
    matches!(u,
        APPLE_SLASH | APPLE_COLON_ALT | APPLE_ASTERISK |
        APPLE_QUESTION | APPLE_QUOTE | APPLE_LESS_THAN |
        APPLE_GREATER_THAN | APPLE_PIPE | APPLE_BACKSLASH |
        APPLE_COLON
    )
}

pub fn map_private_to_ascii(units: &[u16]) -> Vec<u16> {
    units.iter().map(|u| {
        match *u {
            APPLE_SLASH => ASCII_SLASH,
            APPLE_COLON | APPLE_COLON_ALT => ASCII_COLON,
            APPLE_ASTERISK => ASCII_ASTERISK,
            APPLE_QUESTION => ASCII_QUESTION,
            APPLE_QUOTE => ASCII_QUOTE,
            APPLE_LESS_THAN => ASCII_LESS_THAN,
            APPLE_GREATER_THAN => ASCII_GREATER_THAN,
            APPLE_PIPE => ASCII_PIPE,
            APPLE_BACKSLASH => ASCII_BACKSLASH,
            _ => *u,
        }
    }).collect()
}

pub fn map_ascii_to_private(units: &[u16]) -> Vec<u16> {
    units.iter().map(|u| {
        match *u {
            ASCII_SLASH => APPLE_SLASH,
            ASCII_COLON => APPLE_COLON,
            ASCII_ASTERISK => APPLE_ASTERISK,
            ASCII_QUESTION => APPLE_QUESTION,
            ASCII_QUOTE => APPLE_QUOTE,
            ASCII_LESS_THAN => APPLE_LESS_THAN,
            ASCII_GREATER_THAN => APPLE_GREATER_THAN,
            ASCII_PIPE => APPLE_PIPE,
            ASCII_BACKSLASH => APPLE_BACKSLASH,
            _ => *u,
        }
    }).collect()
}

pub fn has_private_range_chars(units: &[u16]) -> bool {
    units.iter().any(|u| is_private_range_char(*u))
}

pub fn has_ntfs_illegal_chars(units: &[u16]) -> bool {
    units.iter().any(|u| {
        matches!(*u,
            ASCII_SLASH | ASCII_COLON | ASCII_ASTERISK |
            ASCII_QUESTION | ASCII_QUOTE | ASCII_LESS_THAN |
            ASCII_GREATER_THAN | ASCII_PIPE | ASCII_BACKSLASH
        )
    })
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_map_private_to_ascii() {
        let input = [APPLE_SLASH, APPLE_COLON, APPLE_QUESTION];
        let output = map_private_to_ascii(&input);
        assert_eq!(output, [ASCII_SLASH, ASCII_COLON, ASCII_QUESTION]);
    }

    #[test]
    fn test_map_private_to_ascii_all() {
        let input = [
            APPLE_SLASH, APPLE_COLON_ALT, APPLE_ASTERISK,
            APPLE_QUESTION, APPLE_QUOTE, APPLE_LESS_THAN,
            APPLE_GREATER_THAN, APPLE_PIPE, APPLE_BACKSLASH,
            APPLE_COLON,
        ];
        let output = map_private_to_ascii(&input);
        assert_eq!(output, [
            ASCII_SLASH, ASCII_COLON, ASCII_ASTERISK,
            ASCII_QUESTION, ASCII_QUOTE, ASCII_LESS_THAN,
            ASCII_GREATER_THAN, ASCII_PIPE, ASCII_BACKSLASH,
            ASCII_COLON,
        ]);
    }

    #[test]
    fn test_map_ascii_to_private() {
        let input = [ASCII_SLASH, ASCII_COLON, ASCII_ASTERISK];
        let output = map_ascii_to_private(&input);
        assert_eq!(output, [APPLE_SLASH, APPLE_COLON, APPLE_ASTERISK]);
    }

    #[test]
    fn test_map_ascii_to_private_all() {
        let input = [
            ASCII_SLASH, ASCII_COLON, ASCII_ASTERISK,
            ASCII_QUESTION, ASCII_QUOTE, ASCII_LESS_THAN,
            ASCII_GREATER_THAN, ASCII_PIPE, ASCII_BACKSLASH,
        ];
        let output = map_ascii_to_private(&input);
        assert_eq!(output, [
            APPLE_SLASH, APPLE_COLON, APPLE_ASTERISK,
            APPLE_QUESTION, APPLE_QUOTE, APPLE_LESS_THAN,
            APPLE_GREATER_THAN, APPLE_PIPE, APPLE_BACKSLASH,
        ]);
    }

    #[test]
    fn test_roundtrip() {
        let original = [ASCII_SLASH, ASCII_COLON, 'a' as u16];
        let to_private = map_ascii_to_private(&original);
        let back_to_ascii = map_private_to_ascii(&to_private);
        assert_eq!(back_to_ascii, original);
    }

    #[test]
    fn test_has_private_range_chars() {
        assert!(has_private_range_chars(&[APPLE_SLASH, 'a' as u16]));
        assert!(!has_private_range_chars(&[ASCII_SLASH, 'a' as u16]));
    }

    #[test]
    fn test_has_ntfs_illegal_chars() {
        assert!(has_ntfs_illegal_chars(&[ASCII_SLASH, 'a' as u16]));
        assert!(!has_ntfs_illegal_chars(&['a' as u16, 'b' as u16]));
    }

    #[test]
    fn test_preserve_non_mapped() {
        let input = ['a' as u16, 'b' as u16, 'c' as u16];
        let output = map_private_to_ascii(&input);
        assert_eq!(output, input);
    }

    #[test]
    fn test_is_private_range_char() {
        assert!(is_private_range_char(APPLE_SLASH));
        assert!(is_private_range_char(APPLE_COLON));
        assert!(!is_private_range_char('a' as u16));
    }
}