//! Types that specify what is contained in a ZIP.
use crate::cp437::FromCp437;
use crate::write::{FileOptionExtension, FileOptions};
use path::{Component, Path, PathBuf};
use std::fmt;
use std::mem;
use std::path;
use std::sync::{Arc, OnceLock};

#[cfg(feature = "chrono")]
use chrono::{Datelike, NaiveDate, NaiveDateTime, NaiveTime, Timelike};

use crate::result::{ZipError, ZipResult};
use crate::spec::{self, FixedSizeBlock};

pub(crate) mod ffi {
    pub const S_IFDIR: u32 = 0o0040000;
    pub const S_IFREG: u32 = 0o0100000;
    pub const S_IFLNK: u32 = 0o0120000;
}

use crate::extra_fields::ExtraField;
use crate::result::DateTimeRangeError;
use crate::spec::is_dir;
use crate::types::ffi::S_IFDIR;
use crate::CompressionMethod;
#[cfg(feature = "time")]
use time::{error::ComponentRange, Date, Month, OffsetDateTime, PrimitiveDateTime, Time};

pub(crate) struct ZipRawValues {
    pub(crate) crc32: u32,
    pub(crate) compressed_size: u64,
    pub(crate) uncompressed_size: u64,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
#[repr(u8)]
pub enum System {
    Dos = 0,
    Unix = 3,
    Unknown,
}

impl From<u8> for System {
    fn from(system: u8) -> Self {
        match system {
            0 => Self::Dos,
            3 => Self::Unix,
            _ => Self::Unknown,
        }
    }
}

impl From<System> for u8 {
    fn from(system: System) -> Self {
        match system {
            System::Dos => 0,
            System::Unix => 3,
            System::Unknown => 4,
        }
    }
}

/// Representation of a moment in time.
///
/// Zip files use an old format from DOS to store timestamps,
/// with its own set of peculiarities.
/// For example, it has a resolution of 2 seconds!
///
/// A [`DateTime`] can be stored directly in a zipfile with [`FileOptions::last_modified_time`],
/// or read from one with [`ZipFile::last_modified`](crate::read::ZipFile::last_modified).
///
/// # Warning
///
/// Because there is no timezone associated with the [`DateTime`], they should ideally only
/// be used for user-facing descriptions.
///
/// Modern zip files store more precise timestamps; see [`crate::extra_fields::ExtendedTimestamp`]
/// for details.
#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct DateTime {
    year: u16,
    month: u8,
    day: u8,
    hour: u8,
    minute: u8,
    second: u8,
}

impl DateTime {
    /// Returns the current time if possible, otherwise the default of 1980-01-01.
    #[cfg(feature = "time")]
    pub fn default_for_write() -> Self {
        OffsetDateTime::now_utc()
            .try_into()
            .unwrap_or_else(|_| DateTime::default())
    }

    /// Returns the current time if possible, otherwise the default of 1980-01-01.
    #[cfg(not(feature = "time"))]
    pub fn default_for_write() -> Self {
        DateTime::default()
    }
}

#[cfg(fuzzing)]
impl arbitrary::Arbitrary<'_> for DateTime {
    fn arbitrary(u: &mut arbitrary::Unstructured) -> arbitrary::Result<Self> {
        Ok(DateTime {
            year: u.int_in_range(1980..=2107)?,
            month: u.int_in_range(1..=12)?,
            day: u.int_in_range(1..=31)?,
            hour: u.int_in_range(0..=23)?,
            minute: u.int_in_range(0..=59)?,
            second: u.int_in_range(0..=58)?,
        })
    }
}

#[cfg(feature = "chrono")]
impl TryFrom<NaiveDateTime> for DateTime {
    type Error = DateTimeRangeError;

    fn try_from(value: NaiveDateTime) -> Result<Self, Self::Error> {
        DateTime::from_date_and_time(
            value.year().try_into()?,
            value.month().try_into()?,
            value.day().try_into()?,
            value.hour().try_into()?,
            value.minute().try_into()?,
            value.second().try_into()?,
        )
    }
}

#[cfg(feature = "chrono")]
impl TryFrom<DateTime> for NaiveDateTime {
    type Error = DateTimeRangeError;

    fn try_from(value: DateTime) -> Result<Self, Self::Error> {
        let date = NaiveDate::from_ymd_opt(value.year.into(), value.month.into(), value.day.into())
            .ok_or(DateTimeRangeError)?;
        let time =
            NaiveTime::from_hms_opt(value.hour.into(), value.minute.into(), value.second.into())
                .ok_or(DateTimeRangeError)?;
        Ok(NaiveDateTime::new(date, time))
    }
}

impl TryFrom<(u16, u16)> for DateTime {
    type Error = DateTimeRangeError;

    #[inline]
    fn try_from(values: (u16, u16)) -> Result<Self, Self::Error> {
        Self::try_from_msdos(values.0, values.1)
    }
}

impl From<DateTime> for (u16, u16) {
    #[inline]
    fn from(dt: DateTime) -> Self {
        (dt.datepart(), dt.timepart())
    }
}

impl Default for DateTime {
    /// Constructs an 'default' datetime of 1980-01-01 00:00:00
    fn default() -> DateTime {
        DateTime {
            year: 1980,
            month: 1,
            day: 1,
            hour: 0,
            minute: 0,
            second: 0,
        }
    }
}

impl fmt::Display for DateTime {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "{:04}-{:02}-{:02} {:02}:{:02}:{:02}",
            self.year, self.month, self.day, self.hour, self.minute, self.second
        )
    }
}

impl DateTime {
    /// Converts an msdos (u16, u16) pair to a DateTime object
    ///
    /// # Safety
    /// The caller must ensure the date and time are valid.
    pub const unsafe fn from_msdos_unchecked(datepart: u16, timepart: u16) -> DateTime {
        let seconds = (timepart & 0b0000000000011111) << 1;
        let minutes = (timepart & 0b0000011111100000) >> 5;
        let hours = (timepart & 0b1111100000000000) >> 11;
        let days = datepart & 0b0000000000011111;
        let months = (datepart & 0b0000000111100000) >> 5;
        let years = (datepart & 0b1111111000000000) >> 9;

        DateTime {
            year: years + 1980,
            month: months as u8,
            day: days as u8,
            hour: hours as u8,
            minute: minutes as u8,
            second: seconds as u8,
        }
    }

    /// Converts an msdos (u16, u16) pair to a DateTime object if it represents a valid date and
    /// time.
    pub fn try_from_msdos(datepart: u16, timepart: u16) -> Result<DateTime, DateTimeRangeError> {
        let seconds = (timepart & 0b0000000000011111) << 1;
        let minutes = (timepart & 0b0000011111100000) >> 5;
        let hours = (timepart & 0b1111100000000000) >> 11;
        let days = datepart & 0b0000000000011111;
        let months = (datepart & 0b0000000111100000) >> 5;
        let years = (datepart & 0b1111111000000000) >> 9;
        Self::from_date_and_time(
            years.checked_add(1980).ok_or(DateTimeRangeError)?,
            months.try_into()?,
            days.try_into()?,
            hours.try_into()?,
            minutes.try_into()?,
            seconds.try_into()?,
        )
    }

    /// Constructs a DateTime from a specific date and time
    ///
    /// The bounds are:
    /// * year: [1980, 2107]
    /// * month: [1, 12]
    /// * day: [1, 28..=31]
    /// * hour: [0, 23]
    /// * minute: [0, 59]
    /// * second: [0, 58]
    pub fn from_date_and_time(
        year: u16,
        month: u8,
        day: u8,
        hour: u8,
        minute: u8,
        second: u8,
    ) -> Result<DateTime, DateTimeRangeError> {
        fn is_leap_year(year: u16) -> bool {
            (year % 4 == 0) && ((year % 25 != 0) || (year % 16 == 0))
        }

        if (1980..=2107).contains(&year)
            && (1..=12).contains(&month)
            && (1..=31).contains(&day)
            && hour <= 23
            && minute <= 59
            && second <= 60
        {
            let second = second.min(58); // exFAT can't store leap seconds
            let max_day = match month {
                1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
                4 | 6 | 9 | 11 => 30,
                2 if is_leap_year(year) => 29,
                2 => 28,
                _ => unreachable!(),
            };
            if day > max_day {
                return Err(DateTimeRangeError);
            }
            Ok(DateTime {
                year,
                month,
                day,
                hour,
                minute,
                second,
            })
        } else {
            Err(DateTimeRangeError)
        }
    }

    /// Indicates whether this date and time can be written to a zip archive.
    pub fn is_valid(&self) -> bool {
        DateTime::from_date_and_time(
            self.year,
            self.month,
            self.day,
            self.hour,
            self.minute,
            self.second,
        )
        .is_ok()
    }

    #[cfg(feature = "time")]
    /// Converts a OffsetDateTime object to a DateTime
    ///
    /// Returns `Err` when this object is out of bounds
    #[deprecated(since = "0.6.4", note = "use `DateTime::try_from()` instead")]
    pub fn from_time(dt: OffsetDateTime) -> Result<DateTime, DateTimeRangeError> {
        dt.try_into()
    }

    /// Gets the time portion of this datetime in the msdos representation
    pub const fn timepart(&self) -> u16 {
        ((self.second as u16) >> 1) | ((self.minute as u16) << 5) | ((self.hour as u16) << 11)
    }

    /// Gets the date portion of this datetime in the msdos representation
    pub const fn datepart(&self) -> u16 {
        (self.day as u16) | ((self.month as u16) << 5) | ((self.year - 1980) << 9)
    }

    #[cfg(feature = "time")]
    /// Converts the DateTime to a OffsetDateTime structure
    #[deprecated(since = "1.3.1", note = "use `OffsetDateTime::try_from()` instead")]
    pub fn to_time(&self) -> Result<OffsetDateTime, ComponentRange> {
        (*self).try_into()
    }

    /// Get the year. There is no epoch, i.e. 2018 will be returned as 2018.
    pub const fn year(&self) -> u16 {
        self.year
    }

    /// Get the month, where 1 = january and 12 = december
    ///
    /// # Warning
    ///
    /// When read from a zip file, this may not be a reasonable value
    pub const fn month(&self) -> u8 {
        self.month
    }

    /// Get the day
    ///
    /// # Warning
    ///
    /// When read from a zip file, this may not be a reasonable value
    pub const fn day(&self) -> u8 {
        self.day
    }

    /// Get the hour
    ///
    /// # Warning
    ///
    /// When read from a zip file, this may not be a reasonable value
    pub const fn hour(&self) -> u8 {
        self.hour
    }

    /// Get the minute
    ///
    /// # Warning
    ///
    /// When read from a zip file, this may not be a reasonable value
    pub const fn minute(&self) -> u8 {
        self.minute
    }

    /// Get the second
    ///
    /// # Warning
    ///
    /// When read from a zip file, this may not be a reasonable value
    pub const fn second(&self) -> u8 {
        self.second
    }
}

#[cfg(feature = "time")]
impl TryFrom<OffsetDateTime> for DateTime {
    type Error = DateTimeRangeError;

    fn try_from(dt: OffsetDateTime) -> Result<Self, Self::Error> {
        if dt.year() >= 1980 && dt.year() <= 2107 {
            Ok(DateTime {
                year: dt.year().try_into()?,
                month: dt.month().into(),
                day: dt.day(),
                hour: dt.hour(),
                minute: dt.minute(),
                second: dt.second(),
            })
        } else {
            Err(DateTimeRangeError)
        }
    }
}

#[cfg(feature = "time")]
impl TryFrom<DateTime> for OffsetDateTime {
    type Error = ComponentRange;

    fn try_from(dt: DateTime) -> Result<Self, Self::Error> {
        let date = Date::from_calendar_date(dt.year as i32, Month::try_from(dt.month)?, dt.day)?;
        let time = Time::from_hms(dt.hour, dt.minute, dt.second)?;
        Ok(PrimitiveDateTime::new(date, time).assume_utc())
    }
}

pub const MIN_VERSION: u8 = 10;
pub const DEFAULT_VERSION: u8 = 45;

/// Structure representing a ZIP file.
#[derive(Debug, Clone)]
pub struct ZipFileData {
    /// Compatibility of the file attribute information
    pub system: System,
    /// Specification version
    pub version_made_by: u8,
    /// True if the file is encrypted.
    pub encrypted: bool,
    /// True if file_name and file_comment are UTF8
    pub is_utf8: bool,
    /// True if the file uses a data-descriptor section
    pub using_data_descriptor: bool,
    /// Compression method used to store the file
    pub compression_method: crate::compression::CompressionMethod,
    /// Compression level to store the file
    pub compression_level: Option<i64>,
    /// Last modified time. This will only have a 2 second precision.
    pub last_modified_time: Option<DateTime>,
    /// CRC32 checksum
    pub crc32: u32,
    /// Size of the file in the ZIP
    pub compressed_size: u64,
    /// Size of the file when extracted
    pub uncompressed_size: u64,
    /// Name of the file
    pub file_name: Box<str>,
    /// Raw file name. To be used when file_name was incorrectly decoded.
    pub file_name_raw: Box<[u8]>,
    /// Extra field usually used for storage expansion
    pub extra_field: Option<Arc<Vec<u8>>>,
    /// Extra field only written to central directory
    pub central_extra_field: Option<Arc<Vec<u8>>>,
    /// File comment
    pub file_comment: Box<str>,
    /// Specifies where the local header of the file starts
    pub header_start: u64,
    /// Specifies where the extra data of the file starts
    pub extra_data_start: Option<u64>,
    /// Specifies where the central header of the file starts
    ///
    /// Note that when this is not known, it is set to 0
    pub central_header_start: u64,
    /// Specifies where the compressed data of the file starts
    pub data_start: OnceLock<u64>,
    /// External file attributes
    pub external_attributes: u32,
    /// Reserve local ZIP64 extra field
    pub large_file: bool,
    /// AES mode if applicable
    pub aes_mode: Option<(AesMode, AesVendorVersion, CompressionMethod)>,
    /// Specifies where in the extra data the AES metadata starts
    pub aes_extra_data_start: u64,

    /// extra fields, see <https://libzip.org/specifications/extrafld.txt>
    pub extra_fields: Vec<ExtraField>,
}

impl ZipFileData {
    #[allow(dead_code)]
    pub fn is_dir(&self) -> bool {
        is_dir(&self.file_name)
    }

    pub fn file_name_sanitized(&self) -> PathBuf {
        let no_null_filename = match self.file_name.find('\0') {
            Some(index) => &self.file_name[0..index],
            None => &self.file_name,
        }
        .to_string();

        // zip files can contain both / and \ as separators regardless of the OS
        // and as we want to return a sanitized PathBuf that only supports the
        // OS separator let's convert incompatible separators to compatible ones
        let separator = path::MAIN_SEPARATOR;
        let opposite_separator = match separator {
            '/' => '\\',
            _ => '/',
        };
        let filename =
            no_null_filename.replace(&opposite_separator.to_string(), &separator.to_string());

        Path::new(&filename)
            .components()
            .filter(|component| matches!(*component, Component::Normal(..)))
            .fold(PathBuf::new(), |mut path, ref cur| {
                path.push(cur.as_os_str());
                path
            })
    }

    pub(crate) fn enclosed_name(&self) -> Option<PathBuf> {
        if self.file_name.contains('\0') {
            return None;
        }
        let path = PathBuf::from(self.file_name.to_string());
        let mut depth = 0usize;
        for component in path.components() {
            match component {
                Component::Prefix(_) | Component::RootDir => return None,
                Component::ParentDir => depth = depth.checked_sub(1)?,
                Component::Normal(_) => depth += 1,
                Component::CurDir => (),
            }
        }
        Some(path)
    }

    /// Get unix mode for the file
    pub(crate) const fn unix_mode(&self) -> Option<u32> {
        if self.external_attributes == 0 {
            return None;
        }

        match self.system {
            System::Unix => Some(self.external_attributes >> 16),
            System::Dos => {
                // Interpret MS-DOS directory bit
                let mut mode = if 0x10 == (self.external_attributes & 0x10) {
                    ffi::S_IFDIR | 0o0775
                } else {
                    ffi::S_IFREG | 0o0664
                };
                if 0x01 == (self.external_attributes & 0x01) {
                    // Read-only bit; strip write permissions
                    mode &= 0o0555;
                }
                Some(mode)
            }
            _ => None,
        }
    }

    /// PKZIP version needed to open this file (from APPNOTE 4.4.3.2).
    pub fn version_needed(&self) -> u16 {
        let compression_version: u16 = match self.compression_method {
            CompressionMethod::Stored => MIN_VERSION.into(),
            #[cfg(feature = "_deflate-any")]
            CompressionMethod::Deflated => 20,
            #[cfg(feature = "bzip2")]
            CompressionMethod::Bzip2 => 46,
            #[cfg(feature = "deflate64")]
            CompressionMethod::Deflate64 => 21,
            #[cfg(feature = "lzma")]
            CompressionMethod::Lzma => 63,
            // APPNOTE doesn't specify a version for Zstandard
            _ => DEFAULT_VERSION as u16,
        };
        let crypto_version: u16 = if self.aes_mode.is_some() {
            51
        } else if self.encrypted {
            20
        } else {
            10
        };
        let misc_feature_version: u16 = if self.large_file {
            45
        } else if self
            .unix_mode()
            .is_some_and(|mode| mode & S_IFDIR == S_IFDIR)
        {
            // file is directory
            20
        } else {
            10
        };
        compression_version
            .max(crypto_version)
            .max(misc_feature_version)
    }
    #[inline(always)]
    pub(crate) fn extra_field_len(&self) -> usize {
        self.extra_field
            .as_ref()
            .map(|v| v.len())
            .unwrap_or_default()
    }
    #[inline(always)]
    pub(crate) fn central_extra_field_len(&self) -> usize {
        self.central_extra_field
            .as_ref()
            .map(|v| v.len())
            .unwrap_or_default()
    }

    #[allow(clippy::too_many_arguments)]
    pub(crate) fn initialize_local_block<S, T: FileOptionExtension>(
        name: S,
        options: &FileOptions<T>,
        raw_values: ZipRawValues,
        header_start: u64,
        extra_data_start: Option<u64>,
        aes_extra_data_start: u64,
        compression_method: crate::compression::CompressionMethod,
        aes_mode: Option<(AesMode, AesVendorVersion, CompressionMethod)>,
        extra_field: Option<Arc<Vec<u8>>>,
    ) -> Self
    where
        S: Into<Box<str>>,
    {
        let permissions = options.permissions.unwrap_or(0o100644);
        let file_name: Box<str> = name.into();
        let file_name_raw: Box<[u8]> = file_name.bytes().collect();
        let mut local_block = ZipFileData {
            system: System::Unix,
            version_made_by: DEFAULT_VERSION,
            encrypted: options.encrypt_with.is_some(),
            using_data_descriptor: false,
            is_utf8: !file_name.is_ascii(),
            compression_method,
            compression_level: options.compression_level,
            last_modified_time: Some(options.last_modified_time),
            crc32: raw_values.crc32,
            compressed_size: raw_values.compressed_size,
            uncompressed_size: raw_values.uncompressed_size,
            file_name, // Never used for saving, but used as map key in insert_file_data()
            file_name_raw,
            extra_field,
            central_extra_field: options.extended_options.central_extra_data().cloned(),
            file_comment: String::with_capacity(0).into_boxed_str(),
            header_start,
            data_start: OnceLock::new(),
            central_header_start: 0,
            external_attributes: permissions << 16,
            large_file: options.large_file,
            aes_mode,
            extra_fields: Vec::new(),
            extra_data_start,
            aes_extra_data_start,
        };
        local_block.version_made_by = local_block.version_needed() as u8;
        local_block
    }

    pub(crate) fn from_local_block<R: std::io::Read>(
        block: ZipLocalEntryBlock,
        reader: &mut R,
    ) -> ZipResult<Self> {
        let ZipLocalEntryBlock {
            // magic,
            version_made_by,
            flags,
            compression_method,
            last_mod_time,
            last_mod_date,
            crc32,
            compressed_size,
            uncompressed_size,
            file_name_length,
            extra_field_length,
            ..
        } = block;

        let encrypted: bool = flags & 1 == 1;
        if encrypted {
            return Err(ZipError::UnsupportedArchive(
                "Encrypted files are not supported",
            ));
        }

        /* FIXME: these were previously incorrect: add testing! */
        /* flags & (1 << 3) != 0 */
        let using_data_descriptor: bool = flags & (1 << 3) == 1 << 3;
        if using_data_descriptor {
            return Err(ZipError::UnsupportedArchive(
                "The file length is not available in the local header",
            ));
        }

        /* flags & (1 << 1) != 0 */
        let is_utf8: bool = flags & (1 << 11) != 0;
        let compression_method = crate::CompressionMethod::parse_from_u16(compression_method);
        let file_name_length: usize = file_name_length.into();
        let extra_field_length: usize = extra_field_length.into();

        let mut file_name_raw = vec![0u8; file_name_length];
        reader.read_exact(&mut file_name_raw)?;
        let mut extra_field = vec![0u8; extra_field_length];
        reader.read_exact(&mut extra_field)?;

        let file_name: Box<str> = match is_utf8 {
            true => String::from_utf8_lossy(&file_name_raw).into(),
            false => file_name_raw.clone().from_cp437().into(),
        };

        let system: u8 = (version_made_by >> 8).try_into().unwrap();
        Ok(ZipFileData {
            system: System::from(system),
            /* NB: this strips the top 8 bits! */
            version_made_by: version_made_by as u8,
            encrypted,
            using_data_descriptor,
            is_utf8,
            compression_method,
            compression_level: None,
            last_modified_time: DateTime::try_from_msdos(last_mod_date, last_mod_time).ok(),
            crc32,
            compressed_size: compressed_size.into(),
            uncompressed_size: uncompressed_size.into(),
            file_name,
            file_name_raw: file_name_raw.into(),
            extra_field: Some(Arc::new(extra_field)),
            central_extra_field: None,
            file_comment: String::with_capacity(0).into_boxed_str(), // file comment is only available in the central directory
            // header_start and data start are not available, but also don't matter, since seeking is
            // not available.
            header_start: 0,
            data_start: OnceLock::new(),
            central_header_start: 0,
            // The external_attributes field is only available in the central directory.
            // We set this to zero, which should be valid as the docs state 'If input came
            // from standard input, this field is set to zero.'
            external_attributes: 0,
            large_file: false,
            aes_mode: None,
            extra_fields: Vec::new(),
            extra_data_start: None,
            aes_extra_data_start: 0,
        })
    }

    fn is_utf8(&self) -> bool {
        std::str::from_utf8(&self.file_name_raw).is_ok()
    }

    fn is_ascii(&self) -> bool {
        self.file_name_raw.is_ascii()
    }

    fn flags(&self) -> u16 {
        let utf8_bit: u16 = if self.is_utf8() && !self.is_ascii() {
            1u16 << 11
        } else {
            0
        };
        let encrypted_bit: u16 = if self.encrypted { 1u16 << 0 } else { 0 };

        utf8_bit | encrypted_bit
    }

    fn clamp_size_field(&self, field: u64) -> u32 {
        if self.large_file {
            spec::ZIP64_BYTES_THR as u32
        } else {
            field.min(spec::ZIP64_BYTES_THR).try_into().unwrap()
        }
    }

    pub(crate) fn local_block(&self) -> ZipResult<ZipLocalEntryBlock> {
        let compressed_size: u32 = self.clamp_size_field(self.compressed_size);
        let uncompressed_size: u32 = self.clamp_size_field(self.uncompressed_size);

        let extra_block_len: usize = self
            .zip64_extra_field_block()
            .map(|block| block.full_size())
            .unwrap_or(0);
        let extra_field_length: u16 = (self.extra_field_len() + extra_block_len)
            .try_into()
            .map_err(|_| ZipError::InvalidArchive("Extra data field is too large"))?;

        let last_modified_time = self
            .last_modified_time
            .unwrap_or_else(DateTime::default_for_write);
        Ok(ZipLocalEntryBlock {
            magic: ZipLocalEntryBlock::MAGIC,
            version_made_by: self.version_needed(),
            flags: self.flags(),
            compression_method: self.compression_method.serialize_to_u16(),
            last_mod_time: last_modified_time.timepart(),
            last_mod_date: last_modified_time.datepart(),
            crc32: self.crc32,
            compressed_size,
            uncompressed_size,
            file_name_length: self.file_name_raw.len().try_into().unwrap(),
            extra_field_length,
        })
    }

    pub(crate) fn block(&self, zip64_extra_field_length: u16) -> ZipCentralEntryBlock {
        let extra_field_len: u16 = self.extra_field_len().try_into().unwrap();
        let central_extra_field_len: u16 = self.central_extra_field_len().try_into().unwrap();
        let last_modified_time = self
            .last_modified_time
            .unwrap_or_else(DateTime::default_for_write);
        ZipCentralEntryBlock {
            magic: ZipCentralEntryBlock::MAGIC,
            version_made_by: (self.system as u16) << 8
                | (self.version_made_by as u16).max(self.version_needed()),
            version_to_extract: self.version_needed(),
            flags: self.flags(),
            compression_method: self.compression_method.serialize_to_u16(),
            last_mod_time: last_modified_time.timepart(),
            last_mod_date: last_modified_time.datepart(),
            crc32: self.crc32,
            compressed_size: self
                .compressed_size
                .min(spec::ZIP64_BYTES_THR)
                .try_into()
                .unwrap(),
            uncompressed_size: self
                .uncompressed_size
                .min(spec::ZIP64_BYTES_THR)
                .try_into()
                .unwrap(),
            file_name_length: self.file_name_raw.len().try_into().unwrap(),
            extra_field_length: zip64_extra_field_length
                + extra_field_len
                + central_extra_field_len,
            file_comment_length: self.file_comment.as_bytes().len().try_into().unwrap(),
            disk_number: 0,
            internal_file_attributes: 0,
            external_file_attributes: self.external_attributes,
            offset: self
                .header_start
                .min(spec::ZIP64_BYTES_THR)
                .try_into()
                .unwrap(),
        }
    }

    pub(crate) fn zip64_extra_field_block(&self) -> Option<Zip64ExtraFieldBlock> {
        let uncompressed_size: Option<u64> =
            if self.uncompressed_size >= spec::ZIP64_BYTES_THR || self.large_file {
                Some(spec::ZIP64_BYTES_THR)
            } else {
                None
            };
        let compressed_size: Option<u64> =
            if self.compressed_size >= spec::ZIP64_BYTES_THR || self.large_file {
                Some(spec::ZIP64_BYTES_THR)
            } else {
                None
            };
        let header_start: Option<u64> = if self.header_start >= spec::ZIP64_BYTES_THR {
            Some(spec::ZIP64_BYTES_THR)
        } else {
            None
        };

        let mut size: u16 = 0;
        if uncompressed_size.is_some() {
            size += mem::size_of::<u64>() as u16;
        }
        if compressed_size.is_some() {
            size += mem::size_of::<u64>() as u16;
        }
        if header_start.is_some() {
            size += mem::size_of::<u64>() as u16;
        }
        if size == 0 {
            return None;
        }

        Some(Zip64ExtraFieldBlock {
            magic: spec::ExtraFieldMagic::ZIP64_EXTRA_FIELD_TAG,
            size,
            uncompressed_size,
            compressed_size,
            header_start,
        })
    }
}

#[derive(Copy, Clone, Debug)]
#[repr(packed)]
pub(crate) struct ZipCentralEntryBlock {
    magic: spec::Magic,
    pub version_made_by: u16,
    pub version_to_extract: u16,
    pub flags: u16,
    pub compression_method: u16,
    pub last_mod_time: u16,
    pub last_mod_date: u16,
    pub crc32: u32,
    pub compressed_size: u32,
    pub uncompressed_size: u32,
    pub file_name_length: u16,
    pub extra_field_length: u16,
    pub file_comment_length: u16,
    pub disk_number: u16,
    pub internal_file_attributes: u16,
    pub external_file_attributes: u32,
    pub offset: u32,
}

impl FixedSizeBlock for ZipCentralEntryBlock {
    const MAGIC: spec::Magic = spec::Magic::CENTRAL_DIRECTORY_HEADER_SIGNATURE;

    #[inline(always)]
    fn magic(self) -> spec::Magic {
        self.magic
    }

    const WRONG_MAGIC_ERROR: ZipError =
        ZipError::InvalidArchive("Invalid Central Directory header");

    to_and_from_le![
        (magic, spec::Magic),
        (version_made_by, u16),
        (version_to_extract, u16),
        (flags, u16),
        (compression_method, u16),
        (last_mod_time, u16),
        (last_mod_date, u16),
        (crc32, u32),
        (compressed_size, u32),
        (uncompressed_size, u32),
        (file_name_length, u16),
        (extra_field_length, u16),
        (file_comment_length, u16),
        (disk_number, u16),
        (internal_file_attributes, u16),
        (external_file_attributes, u32),
        (offset, u32),
    ];
}

#[derive(Copy, Clone, Debug)]
#[repr(packed)]
pub(crate) struct ZipLocalEntryBlock {
    magic: spec::Magic,
    pub version_made_by: u16,
    pub flags: u16,
    pub compression_method: u16,
    pub last_mod_time: u16,
    pub last_mod_date: u16,
    pub crc32: u32,
    pub compressed_size: u32,
    pub uncompressed_size: u32,
    pub file_name_length: u16,
    pub extra_field_length: u16,
}

impl FixedSizeBlock for ZipLocalEntryBlock {
    const MAGIC: spec::Magic = spec::Magic::LOCAL_FILE_HEADER_SIGNATURE;

    #[inline(always)]
    fn magic(self) -> spec::Magic {
        self.magic
    }

    const WRONG_MAGIC_ERROR: ZipError = ZipError::InvalidArchive("Invalid local file header");

    to_and_from_le![
        (magic, spec::Magic),
        (version_made_by, u16),
        (flags, u16),
        (compression_method, u16),
        (last_mod_time, u16),
        (last_mod_date, u16),
        (crc32, u32),
        (compressed_size, u32),
        (uncompressed_size, u32),
        (file_name_length, u16),
        (extra_field_length, u16),
    ];
}

#[derive(Copy, Clone, Debug)]
pub(crate) struct Zip64ExtraFieldBlock {
    magic: spec::ExtraFieldMagic,
    size: u16,
    uncompressed_size: Option<u64>,
    compressed_size: Option<u64>,
    header_start: Option<u64>,
    // Excluded fields:
    // u32: disk start number
}

impl Zip64ExtraFieldBlock {
    pub fn full_size(&self) -> usize {
        assert!(self.size > 0);
        self.size as usize + mem::size_of::<spec::ExtraFieldMagic>() + mem::size_of::<u16>()
    }

    pub fn serialize(self) -> Box<[u8]> {
        let Self {
            magic,
            size,
            uncompressed_size,
            compressed_size,
            header_start,
        } = self;

        let full_size = self.full_size();

        let mut ret = Vec::with_capacity(full_size);
        ret.extend(magic.to_le_bytes());
        ret.extend(u16::to_le_bytes(size));

        if let Some(uncompressed_size) = uncompressed_size {
            ret.extend(u64::to_le_bytes(uncompressed_size));
        }
        if let Some(compressed_size) = compressed_size {
            ret.extend(u64::to_le_bytes(compressed_size));
        }
        if let Some(header_start) = header_start {
            ret.extend(u64::to_le_bytes(header_start));
        }
        debug_assert_eq!(ret.len(), full_size);

        ret.into_boxed_slice()
    }
}

/// The encryption specification used to encrypt a file with AES.
///
/// According to the [specification](https://www.winzip.com/win/en/aes_info.html#winzip11) AE-2
/// does not make use of the CRC check.
#[derive(Copy, Clone, Debug)]
#[repr(u16)]
pub enum AesVendorVersion {
    Ae1 = 0x0001,
    Ae2 = 0x0002,
}

/// AES variant used.
#[derive(Copy, Clone, Debug)]
#[cfg_attr(fuzzing, derive(arbitrary::Arbitrary))]
#[repr(u8)]
pub enum AesMode {
    /// 128-bit AES encryption.
    Aes128 = 0x01,
    /// 192-bit AES encryption.
    Aes192 = 0x02,
    /// 256-bit AES encryption.
    Aes256 = 0x03,
}

#[cfg(feature = "aes-crypto")]
impl AesMode {
    /// Length of the salt for the given AES mode.
    pub const fn salt_length(&self) -> usize {
        self.key_length() / 2
    }

    /// Length of the key for the given AES mode.
    pub const fn key_length(&self) -> usize {
        match self {
            Self::Aes128 => 16,
            Self::Aes192 => 24,
            Self::Aes256 => 32,
        }
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn system() {
        use super::System;
        assert_eq!(u8::from(System::Dos), 0u8);
        assert_eq!(System::Dos as u8, 0u8);
        assert_eq!(System::Unix as u8, 3u8);
        assert_eq!(u8::from(System::Unix), 3u8);
        assert_eq!(System::from(0), System::Dos);
        assert_eq!(System::from(3), System::Unix);
        assert_eq!(u8::from(System::Unknown), 4u8);
        assert_eq!(System::Unknown as u8, 4u8);
    }

    #[test]
    fn sanitize() {
        use super::*;
        let file_name = "/path/../../../../etc/./passwd\0/etc/shadow".to_string();
        let data = ZipFileData {
            system: System::Dos,
            version_made_by: 0,
            encrypted: false,
            using_data_descriptor: false,
            is_utf8: true,
            compression_method: crate::compression::CompressionMethod::Stored,
            compression_level: None,
            last_modified_time: None,
            crc32: 0,
            compressed_size: 0,
            uncompressed_size: 0,
            file_name: file_name.clone().into_boxed_str(),
            file_name_raw: file_name.into_bytes().into_boxed_slice(),
            extra_field: None,
            central_extra_field: None,
            file_comment: String::with_capacity(0).into_boxed_str(),
            header_start: 0,
            extra_data_start: None,
            data_start: OnceLock::new(),
            central_header_start: 0,
            external_attributes: 0,
            large_file: false,
            aes_mode: None,
            aes_extra_data_start: 0,
            extra_fields: Vec::new(),
        };
        assert_eq!(data.file_name_sanitized(), PathBuf::from("path/etc/passwd"));
    }

    #[test]
    #[allow(clippy::unusual_byte_groupings)]
    fn datetime_default() {
        use super::DateTime;
        let dt = DateTime::default();
        assert_eq!(dt.timepart(), 0);
        assert_eq!(dt.datepart(), 0b0000000_0001_00001);
    }

    #[test]
    #[allow(clippy::unusual_byte_groupings)]
    fn datetime_max() {
        use super::DateTime;
        let dt = DateTime::from_date_and_time(2107, 12, 31, 23, 59, 58).unwrap();
        assert_eq!(dt.timepart(), 0b10111_111011_11101);
        assert_eq!(dt.datepart(), 0b1111111_1100_11111);
    }

    #[test]
    fn datetime_equality() {
        use super::DateTime;

        let dt = DateTime::from_date_and_time(2018, 11, 17, 10, 38, 30).unwrap();
        assert_eq!(
            dt,
            DateTime::from_date_and_time(2018, 11, 17, 10, 38, 30).unwrap()
        );
        assert_ne!(dt, DateTime::default());
    }

    #[test]
    fn datetime_order() {
        use std::cmp::Ordering;

        use super::DateTime;

        let dt = DateTime::from_date_and_time(2018, 11, 17, 10, 38, 30).unwrap();
        assert_eq!(
            dt.cmp(&DateTime::from_date_and_time(2018, 11, 17, 10, 38, 30).unwrap()),
            Ordering::Equal
        );
        // year
        assert!(dt < DateTime::from_date_and_time(2019, 11, 17, 10, 38, 30).unwrap());
        assert!(dt > DateTime::from_date_and_time(2017, 11, 17, 10, 38, 30).unwrap());
        // month
        assert!(dt < DateTime::from_date_and_time(2018, 12, 17, 10, 38, 30).unwrap());
        assert!(dt > DateTime::from_date_and_time(2018, 10, 17, 10, 38, 30).unwrap());
        // day
        assert!(dt < DateTime::from_date_and_time(2018, 11, 18, 10, 38, 30).unwrap());
        assert!(dt > DateTime::from_date_and_time(2018, 11, 16, 10, 38, 30).unwrap());
        // hour
        assert!(dt < DateTime::from_date_and_time(2018, 11, 17, 11, 38, 30).unwrap());
        assert!(dt > DateTime::from_date_and_time(2018, 11, 17, 9, 38, 30).unwrap());
        // minute
        assert!(dt < DateTime::from_date_and_time(2018, 11, 17, 10, 39, 30).unwrap());
        assert!(dt > DateTime::from_date_and_time(2018, 11, 17, 10, 37, 30).unwrap());
        // second
        assert!(dt < DateTime::from_date_and_time(2018, 11, 17, 10, 38, 31).unwrap());
        assert!(dt > DateTime::from_date_and_time(2018, 11, 17, 10, 38, 29).unwrap());
    }

    #[test]
    fn datetime_display() {
        use super::DateTime;

        assert_eq!(format!("{}", DateTime::default()), "1980-01-01 00:00:00");
        assert_eq!(
            format!(
                "{}",
                DateTime::from_date_and_time(2018, 11, 17, 10, 38, 30).unwrap()
            ),
            "2018-11-17 10:38:30"
        );
        assert_eq!(
            format!(
                "{}",
                DateTime::from_date_and_time(2107, 12, 31, 23, 59, 58).unwrap()
            ),
            "2107-12-31 23:59:58"
        );
    }

    #[test]
    fn datetime_bounds() {
        use super::DateTime;

        assert!(DateTime::from_date_and_time(2000, 1, 1, 23, 59, 60).is_ok());
        assert!(DateTime::from_date_and_time(2000, 1, 1, 24, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2000, 1, 1, 0, 60, 0).is_err());
        assert!(DateTime::from_date_and_time(2000, 1, 1, 0, 0, 61).is_err());

        assert!(DateTime::from_date_and_time(2107, 12, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(1980, 1, 1, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(1979, 1, 1, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(1980, 0, 1, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(1980, 1, 0, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2108, 12, 31, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2107, 13, 31, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2107, 12, 32, 0, 0, 0).is_err());

        assert!(DateTime::from_date_and_time(2018, 1, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 2, 28, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 2, 29, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2018, 3, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 4, 30, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 4, 31, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2018, 5, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 6, 30, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 6, 31, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2018, 7, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 8, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 9, 30, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 9, 31, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2018, 10, 31, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 11, 30, 0, 0, 0).is_ok());
        assert!(DateTime::from_date_and_time(2018, 11, 31, 0, 0, 0).is_err());
        assert!(DateTime::from_date_and_time(2018, 12, 31, 0, 0, 0).is_ok());

        // leap year: divisible by 4
        assert!(DateTime::from_date_and_time(2024, 2, 29, 0, 0, 0).is_ok());
        // leap year: divisible by 100 and by 400
        assert!(DateTime::from_date_and_time(2000, 2, 29, 0, 0, 0).is_ok());
        // common year: divisible by 100 but not by 400
        assert!(DateTime::from_date_and_time(2100, 2, 29, 0, 0, 0).is_err());
    }

    #[cfg(feature = "time")]
    use time::{format_description::well_known::Rfc3339, OffsetDateTime};

    #[cfg(feature = "time")]
    #[test]
    fn datetime_try_from_offset_datetime() {
        use time::macros::datetime;

        use super::DateTime;

        // 2018-11-17 10:38:30
        let dt = DateTime::try_from(datetime!(2018-11-17 10:38:30 UTC)).unwrap();
        assert_eq!(dt.year(), 2018);
        assert_eq!(dt.month(), 11);
        assert_eq!(dt.day(), 17);
        assert_eq!(dt.hour(), 10);
        assert_eq!(dt.minute(), 38);
        assert_eq!(dt.second(), 30);
    }

    #[cfg(feature = "time")]
    #[test]
    fn datetime_try_from_bounds() {
        use super::DateTime;
        use time::macros::datetime;

        // 1979-12-31 23:59:59
        assert!(DateTime::try_from(datetime!(1979-12-31 23:59:59 UTC)).is_err());

        // 1980-01-01 00:00:00
        assert!(DateTime::try_from(datetime!(1980-01-01 00:00:00 UTC)).is_ok());

        // 2107-12-31 23:59:59
        assert!(DateTime::try_from(datetime!(2107-12-31 23:59:59 UTC)).is_ok());

        // 2108-01-01 00:00:00
        assert!(DateTime::try_from(datetime!(2108-01-01 00:00:00 UTC)).is_err());
    }

    #[cfg(feature = "time")]
    #[test]
    fn offset_datetime_try_from_datetime() {
        use time::macros::datetime;

        use super::DateTime;

        // 2018-11-17 10:38:30 UTC
        let dt =
            OffsetDateTime::try_from(DateTime::try_from_msdos(0x4D71, 0x54CF).unwrap()).unwrap();
        assert_eq!(dt, datetime!(2018-11-17 10:38:30 UTC));
    }

    #[cfg(feature = "time")]
    #[test]
    fn offset_datetime_try_from_bounds() {
        use super::DateTime;

        // 1980-00-00 00:00:00
        assert!(OffsetDateTime::try_from(unsafe {
            DateTime::from_msdos_unchecked(0x0000, 0x0000)
        })
        .is_err());

        // 2107-15-31 31:63:62
        assert!(OffsetDateTime::try_from(unsafe {
            DateTime::from_msdos_unchecked(0xFFFF, 0xFFFF)
        })
        .is_err());
    }

    #[test]
    #[allow(deprecated)]
    fn time_conversion() {
        use super::DateTime;
        let dt = DateTime::try_from_msdos(0x4D71, 0x54CF).unwrap();
        assert_eq!(dt.year(), 2018);
        assert_eq!(dt.month(), 11);
        assert_eq!(dt.day(), 17);
        assert_eq!(dt.hour(), 10);
        assert_eq!(dt.minute(), 38);
        assert_eq!(dt.second(), 30);

        let dt = DateTime::try_from((0x4D71, 0x54CF)).unwrap();
        assert_eq!(dt.year(), 2018);
        assert_eq!(dt.month(), 11);
        assert_eq!(dt.day(), 17);
        assert_eq!(dt.hour(), 10);
        assert_eq!(dt.minute(), 38);
        assert_eq!(dt.second(), 30);

        #[cfg(feature = "time")]
        assert_eq!(
            dt.to_time().unwrap().format(&Rfc3339).unwrap(),
            "2018-11-17T10:38:30Z"
        );

        assert_eq!(<(u16, u16)>::from(dt), (0x4D71, 0x54CF));
    }

    #[test]
    #[allow(deprecated)]
    fn time_out_of_bounds() {
        use super::DateTime;
        let dt = unsafe { DateTime::from_msdos_unchecked(0xFFFF, 0xFFFF) };
        assert_eq!(dt.year(), 2107);
        assert_eq!(dt.month(), 15);
        assert_eq!(dt.day(), 31);
        assert_eq!(dt.hour(), 31);
        assert_eq!(dt.minute(), 63);
        assert_eq!(dt.second(), 62);

        #[cfg(feature = "time")]
        assert!(dt.to_time().is_err());

        let dt = unsafe { DateTime::from_msdos_unchecked(0x0000, 0x0000) };
        assert_eq!(dt.year(), 1980);
        assert_eq!(dt.month(), 0);
        assert_eq!(dt.day(), 0);
        assert_eq!(dt.hour(), 0);
        assert_eq!(dt.minute(), 0);
        assert_eq!(dt.second(), 0);

        #[cfg(feature = "time")]
        assert!(dt.to_time().is_err());
    }

    #[cfg(feature = "time")]
    #[test]
    fn time_at_january() {
        use super::DateTime;

        // 2020-01-01 00:00:00
        let clock = OffsetDateTime::from_unix_timestamp(1_577_836_800).unwrap();

        assert!(DateTime::try_from(clock).is_ok());
    }
}
