//! Common types use throughout
use log::{trace, warn};
use memmap2::{Mmap, MmapOptions};
use std::fmt::{Debug, Display};
use std::io::{Read, Seek, Write};
use std::ops::Deref;
use std::str::FromStr;

use crate::headers::NitfSegmentHeader;
use crate::{NitfError, NitfResult};

/// Lowest level object for file parsing
#[derive(Default, Clone, Debug, Eq, PartialEq)]
pub struct NitfField<V: FromStr + Debug + Default + Display> {
    /// Parsed representation of value
    pub val: V,
    /// Number of bytes used to store value in file
    pub length: usize,
    /// Name of field
    pub name: String,
}

/// Provide default field implementations.
impl<V> NitfField<V>
where
    V: FromStr + Debug + Default + Display,
    <V as FromStr>::Err: Debug,
{
    pub fn init(length: u8, name: &str) -> Self {
        Self {
            val: V::default(),
            length: length.into(),
            name: name.to_string(),
        }
    }
    // Reading/Writing

    /// Read the specified number of bytes and parse the value of a given field
    pub fn read(&mut self, reader: &mut (impl Read + Seek)) -> NitfResult<()> {
        let mut bytes = vec![0; self.length];
        let string;

        // Crash if something goes wrong with the cursor
        let offset = reader
            .stream_position()
            .or(Err(NitfError::ReadFatal(self.name.clone())))?;

        // Crash if there is an error reading the bytes
        reader
            .read_exact(&mut bytes)
            .or(Err(NitfError::ReadFatal(self.name.clone())))?;

        // Try to read the bytes to a string
        match String::from_utf8(bytes.to_vec()) {
            // If it's ok, trim and try to parse to enum/native representation
            Ok(str) => {
                string = str.clone();
                // Warn and assign a default value if error parsing
                self.val = str.trim().parse().unwrap_or_else(|e| {
                    warn!("Non-fatal error parsing {}: {e:?}", self.name);
                    V::default()
                });
            }

            Err(_) => {
                string = "Error parsing to string".to_string();
                warn!("Failed to parse {} from bytes: {bytes:?}", self.name);
            }
        }
        trace!("Read {} at offset {offset}: {string}", self.name);
        Ok(())
    }

    pub fn write(&self, writer: &mut (impl Write + Seek)) -> NitfResult<usize> {
        let buf = format!("{:<1$}", self.val.to_string(), self.length);
        let offset = writer.stream_position()?;
        trace!(
            "Wrote {} bytes for {} at {offset}: {buf}",
            buf.len(),
            self.name
        );
        writer.write(buf.as_bytes()).map_err(NitfError::IOError)
    }
}

impl<V: FromStr + Debug + Default + Display> Display for NitfField<V> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}: {:<2$}",
            self.name,
            self.val.to_string(),
            self.length
        )
    }
}

#[derive(Default, Debug, Clone, PartialEq, Eq, Copy)]
pub struct NitfSegment<T: NitfSegmentHeader> {
    /// Header fields defined in module
    pub header: T,
    /// Segment data offset
    pub header_offset: u64,
    /// Segment data size
    pub data_size: u64,
    /// Segment data offset
    pub data_offset: u64,
}
impl<T: NitfSegmentHeader> NitfSegment<T> {
    pub(crate) fn read(reader: &mut (impl Read + Seek), data_size: u64) -> NitfResult<Self> {
        let header_offset = reader.stream_position()?;
        let header = T::from_reader(reader)?;
        let data_offset = reader.stream_position()?;
        // Seek to end of data for next segment to be read
        reader.seek(std::io::SeekFrom::Start(data_offset + data_size))?;
        Ok(Self {
            header,
            header_offset,
            data_size,
            data_offset,
        })
    }
    /// Write segment header to file
    pub(crate) fn write_header(&mut self, writer: &mut (impl Write + Seek)) -> NitfResult<usize> {
        writer.seek(std::io::SeekFrom::Start(self.header_offset))?;
        let bytes_written = self.header.write(writer)?;
        self.data_offset = writer.stream_position()?;
        Ok(bytes_written)
    }

    /// Memory-map the data from this segment.
    pub fn get_data_map(&self, reader: &mut std::fs::File) -> NitfResult<Mmap> {
        if self.data_offset == 0 {
            Err(NitfError::Fatal(
                "Data offset location is not set. Cannot read data".to_string(),
            ))?
        }
        let mut opts = MmapOptions::new();
        Ok(unsafe {
            opts.len(self.data_size as usize)
                .offset(self.data_offset)
                .map(reader.deref())
        }?)
    }
    /// Write segment data to file. Assumes cursor is in correct position
    pub fn write_data(&self, writer: &mut (impl Write + Seek), data: &[u8]) -> NitfResult<usize> {
        writer.seek(std::io::SeekFrom::Start(self.data_offset))?;
        writer.write(data).map_err(NitfError::IOError)
    }
    pub fn length(&self) -> usize {
        self.header.length() + self.data_size as usize
    }
}
impl<T: NitfSegmentHeader + Display> Display for NitfSegment<T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.header)
    }
}
/// Standard security metadata
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct Security {
    /// File Security Classification
    pub clas: NitfField<Classification>,
    /// File Classification Security System
    pub clsy: NitfField<String>, // TODO: Check value registry
    /// File Codewords
    pub code: NitfField<String>,
    /// File Control and Handling
    pub ctlh: NitfField<String>,
    /// File Releasing Instructions
    pub rel: NitfField<String>,
    /// File Declassification Type
    pub dctp: NitfField<DeclassificationType>,
    /// File Declassification Date
    pub dcdt: NitfField<String>,
    /// File Declassification Exemption
    pub dcxm: NitfField<DeclassificationExemption>,
    /// File Downgrade
    pub dg: NitfField<Downgrade>,
    /// File Downgrade Date
    pub dgdt: NitfField<String>,
    /// File Classification Text
    pub cltx: NitfField<String>,
    /// File Classification Authority Type
    pub catp: NitfField<ClassificationAuthorityType>,
    /// File Classification Authority
    pub caut: NitfField<String>,
    /// File Classification Reason
    pub crsn: NitfField<ClassificationReason>, // TODO: Check value registry
    /// File Security Source Date
    pub srdt: NitfField<String>,
    /// File Security Control Number
    pub ctln: NitfField<String>,
}

impl Default for Security {
    fn default() -> Self {
        Self {
            clas: NitfField::init(1u8, "CLAS"),
            clsy: NitfField::init(2u8, "CLSY"),
            code: NitfField::init(11u8, "CODE"),
            ctlh: NitfField::init(2u8, "CTLH"),
            rel: NitfField::init(20u8, "REL"),
            dctp: NitfField::init(2u8, "DCTP"),
            dcdt: NitfField::init(8u8, "DCDT"),
            dcxm: NitfField::init(4u8, "DCXM"),
            dg: NitfField::init(1u8, "DG"),
            dgdt: NitfField::init(8u8, "DGDT"),
            cltx: NitfField::init(43u8, "CLTX"),
            catp: NitfField::init(1u8, "CATP"),
            caut: NitfField::init(40u8, "CAUT"),
            crsn: NitfField::init(1u8, "CRSN"),
            srdt: NitfField::init(8u8, "SRDT"),
            ctln: NitfField::init(15u8, "CTLN"),
        }
    }
}

impl Security {
    pub fn read(&mut self, reader: &mut (impl Read + Seek)) -> NitfResult<()> {
        self.clas.read(reader)?;
        self.clsy.read(reader)?;
        self.code.read(reader)?;
        self.ctlh.read(reader)?;
        self.rel.read(reader)?;
        self.dctp.read(reader)?;
        self.dcdt.read(reader)?;
        self.dcxm.read(reader)?;
        self.dg.read(reader)?;
        self.dgdt.read(reader)?;
        self.cltx.read(reader)?;
        self.catp.read(reader)?;
        self.caut.read(reader)?;
        self.crsn.read(reader)?;
        self.srdt.read(reader)?;
        self.ctln.read(reader)?;
        Ok(())
    }
    pub fn write(&self, writer: &mut (impl Write + Seek)) -> NitfResult<usize> {
        let mut bytes_written = 0;
        bytes_written += self.clas.write(writer)?;
        bytes_written += self.clsy.write(writer)?;
        bytes_written += self.code.write(writer)?;
        bytes_written += self.ctlh.write(writer)?;
        bytes_written += self.rel.write(writer)?;
        bytes_written += self.dctp.write(writer)?;
        bytes_written += self.dcdt.write(writer)?;
        bytes_written += self.dcxm.write(writer)?;
        bytes_written += self.dg.write(writer)?;
        bytes_written += self.dgdt.write(writer)?;
        bytes_written += self.cltx.write(writer)?;
        bytes_written += self.catp.write(writer)?;
        bytes_written += self.caut.write(writer)?;
        bytes_written += self.crsn.write(writer)?;
        bytes_written += self.srdt.write(writer)?;
        bytes_written += self.ctln.write(writer)?;
        Ok(bytes_written)
    }
    /// Sum of all security fields
    pub fn length(&self) -> usize {
        167
    }
}
impl Display for Security {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let mut out_str = String::default();
        out_str += &format!("{}, ", self.clas);
        out_str += &format!("{}, ", self.clsy);
        out_str += &format!("{}, ", self.code);
        out_str += &format!("{}, ", self.ctlh);
        out_str += &format!("{}, ", self.rel);
        out_str += &format!("{}, ", self.dctp);
        out_str += &format!("{}, ", self.dcdt);
        out_str += &format!("{}, ", self.dcxm);
        out_str += &format!("{}, ", self.dg);
        out_str += &format!("{}, ", self.dgdt);
        out_str += &format!("{}, ", self.cltx);
        out_str += &format!("{}, ", self.catp);
        out_str += &format!("{}, ", self.caut);
        out_str += &format!("{}, ", self.crsn);
        out_str += &format!("{}, ", self.srdt);
        out_str += &format!("{}", self.ctln);
        write!(f, "{out_str}")
    }
}

/// Classification codes
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum Classification {
    #[default]
    /// Unclassified
    U,
    /// Top Secret
    T,
    /// Secret
    S,
    /// Confidential
    C,
    /// Restricted
    R,
}
impl FromStr for Classification {
    type Err = NitfError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "U" => Ok(Self::U),
            "T" => Ok(Self::T),
            "S" => Ok(Self::S),
            "C" => Ok(Self::C),
            "R" => Ok(Self::R),
            _ => Err(NitfError::ParseError("Classification".to_string())),
        }
    }
}
impl Display for Classification {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::U => write!(f, "U"),
            Self::T => write!(f, "T"),
            Self::S => write!(f, "S"),
            Self::C => write!(f, "C"),
            Self::R => write!(f, "R"),
        }
    }
}
/// Declassification codes
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum DeclassificationType {
    #[default]
    /// Default value, two spaces
    DEFAULT,
    /// Declassify on specific date
    DD,
    /// Declassify on occurrence of event
    DE,
    /// Downgrade to specified level on specific date
    GD,
    /// Downgrade to specified level on occurrence of event
    GE,
    /// OADR
    O,
    /// Exempt from automatic declassification
    X,
}
impl FromStr for DeclassificationType {
    type Err = NitfError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "" => Ok(Self::DEFAULT),
            "DD" => Ok(Self::DD),
            "DE" => Ok(Self::DE),
            "GD" => Ok(Self::GD),
            "GE" => Ok(Self::GE),
            "O" => Ok(Self::O),
            "X" => Ok(Self::X),
            _ => Err(NitfError::ParseError("DeclassificationType".to_string())),
        }
    }
}
impl Display for DeclassificationType {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::DEFAULT => write!(f, "  "),
            Self::DD => write!(f, "DD"),
            Self::DE => write!(f, "DE"),
            Self::GD => write!(f, "GD"),
            Self::GE => write!(f, "GE"),
            Self::O => write!(f, "O"),
            Self::X => write!(f, "X"),
        }
    }
}

///  Declassification exemption
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum DeclassificationExemption {
    #[default]
    /// Default value, four spaces
    DEFAULT,
    /// Valid values
    DExX1,
    DExX2,
    DExX3,
    DExX4,
    DExX5,
    DExX6,
    DExX7,
    DExX8,
    DEx25X1,
    DEx25X2,
    DEx25X3,
    DEx25X4,
    DEx25X5,
    DEx25X6,
    DEx25X7,
    DEx25X8,
    DEx25X9,
    DExDN10,
    DExDNI,
}
impl FromStr for DeclassificationExemption {
    type Err = NitfError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "" => Ok(Self::DEFAULT),
            "X1" => Ok(Self::DExX1),     // DOD 5200.01-V1, 4-201b(1)
            "X2" => Ok(Self::DExX2),     // DOD 5200.01-V1, 4-201b(2)
            "X3" => Ok(Self::DExX3),     // DOD 5200.01-V1, 4-201b(3)
            "X4" => Ok(Self::DExX4),     // DOD 5200.01-V1, 4-201b(4)
            "X5" => Ok(Self::DExX5),     // DOD 5200.01-V1, 4-201b(5)
            "X6" => Ok(Self::DExX6),     // DOD 5200.01-V1, 4-201b(6)
            "X7" => Ok(Self::DExX7),     // DOD 5200.01-V1, 4-201b(7)
            "X8" => Ok(Self::DExX8),     // DOD 5200.01-V1, 4-201b(8)
            "25X1" => Ok(Self::DEx25X1), // DOD 5200.01-V1, 4-301b(1)
            "25X2" => Ok(Self::DEx25X2), // DOD 5200.01-V1, 4-301b(2)
            "25X3" => Ok(Self::DEx25X3), // DOD 5200.01-V1, 4-301b(3)
            "25X4" => Ok(Self::DEx25X4), // DOD 5200.01-V1, 4-301b(4)
            "25X5" => Ok(Self::DEx25X5), // DOD 5200.01-V1, 4-301b(5)
            "25X6" => Ok(Self::DEx25X6), // DOD 5200.01-V1, 4-301b(6)
            "25X7" => Ok(Self::DEx25X7), // DOD 5200.01-V1, 4-301b(7)
            "25X8" => Ok(Self::DEx25X8), // DOD 5200.01-V1, 4-301b(8)
            "25X9" => Ok(Self::DEx25X9), // DOD 5200.01-V1, 4-301b(9)
            "DN10" => Ok(Self::DExDN10),
            "DNI" => Ok(Self::DExDNI),
            _ => Err(NitfError::ParseError(
                "DeclassificationExemption".to_string(),
            )),
        }
    }
}
impl Display for DeclassificationExemption {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::DEFAULT => write!(f, ""),
            Self::DExX1 => write!(f, "X1"),
            Self::DExX2 => write!(f, "X2"),
            Self::DExX3 => write!(f, "X3"),
            Self::DExX4 => write!(f, "X4"),
            Self::DExX5 => write!(f, "X5"),
            Self::DExX6 => write!(f, "X6"),
            Self::DExX7 => write!(f, "X7"),
            Self::DExX8 => write!(f, "X8"),
            Self::DEx25X1 => write!(f, "25X1"),
            Self::DEx25X2 => write!(f, "25X2"),
            Self::DEx25X3 => write!(f, "25X3"),
            Self::DEx25X4 => write!(f, "25X4"),
            Self::DEx25X5 => write!(f, "25X5"),
            Self::DEx25X6 => write!(f, "25X6"),
            Self::DEx25X7 => write!(f, "25X7"),
            Self::DEx25X8 => write!(f, "25X8"),
            Self::DEx25X9 => write!(f, "25X9"),
            Self::DExDN10 => write!(f, "DN10"),
            Self::DExDNI => write!(f, "DNI"),
        }
    }
}

/// Downgrade classification
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum Downgrade {
    #[default]
    /// Default value, two spaces
    DEFAULT,
    /// Secret
    S,
    /// Confidential
    C,
    /// Restricted
    R,
}
impl FromStr for Downgrade {
    type Err = NitfError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "" => Ok(Self::DEFAULT),
            "S" => Ok(Self::S),
            "C" => Ok(Self::C),
            "R" => Ok(Self::R),
            _ => Err(NitfError::ParseError("Downgrade".to_string())),
        }
    }
}
impl Display for Downgrade {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::DEFAULT => write!(f, ""),
            Self::S => write!(f, "S"),
            Self::C => write!(f, "C"),
            Self::R => write!(f, "R"),
        }
    }
}

/// Classification authority
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum ClassificationAuthorityType {
    #[default]
    /// Default, one space
    DEFAULT,
    /// Original classification authority
    O,
    /// Derivative from a single source
    D,
    /// Derivative from multiple sources
    M,
}
impl FromStr for ClassificationAuthorityType {
    type Err = NitfError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "" => Ok(Self::DEFAULT),
            "O" => Ok(Self::O),
            "D" => Ok(Self::D),
            "M" => Ok(Self::M),
            _ => Err(NitfError::ParseError(
                "ClassificationAuthorityType".to_string(),
            )),
        }
    }
}
impl Display for ClassificationAuthorityType {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::DEFAULT => write!(f, ""),
            Self::O => write!(f, "O"),
            Self::D => write!(f, "D"),
            Self::M => write!(f, "M"),
        }
    }
}

/// Reason for classification
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub enum ClassificationReason {
    #[default]
    /// Default value, one space
    DEFAULT,
    /// Valid values
    A,
    B,
    C,
    D,
    E,
    F,
    G,
    H,
}
impl FromStr for ClassificationReason {
    type Err = NitfError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "" => Ok(Self::DEFAULT),
            "A" => Ok(Self::A),
            "B" => Ok(Self::B),
            "C" => Ok(Self::C),
            "D" => Ok(Self::D),
            "E" => Ok(Self::E),
            "F" => Ok(Self::F),
            "G" => Ok(Self::G),
            "H" => Ok(Self::H),
            _ => Err(NitfError::ParseError("ClassificationReason".to_string())),
        }
    }
}
impl Display for ClassificationReason {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::DEFAULT => write!(f, ""),
            Self::A => write!(f, "A"),
            Self::B => write!(f, "B"),
            Self::C => write!(f, "C"),
            Self::D => write!(f, "D"),
            Self::E => write!(f, "E"),
            Self::F => write!(f, "F"),
            Self::G => write!(f, "G"),
            Self::H => write!(f, "H"),
        }
    }
}

/// Extended sub-header TRE data type
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub struct ExtendedSubheader {
    /// User defined tagged record entries (TREs)
    tre: Vec<u8>,
    /// Length of subheader
    size: usize,
    /// Name of subheader
    pub name: String,
}
impl ExtendedSubheader {
    /// Get `tre`
    pub fn tre(&self) -> &Vec<u8> {
        &self.tre
    }
    /// Get `size`
    pub fn size(&self) -> &usize {
        &self.size
    }
    pub fn init(name: &str) -> Self {
        Self {
            tre: vec![],
            size: 0,
            name: name.to_string(),
        }
    }
    /// Updates the TRE byte vector and size field.
    pub fn set_tre(&mut self, new_tre: Vec<u8>) {
        self.size = new_tre.len();
        self.tre = new_tre;
    }
    pub fn read(&mut self, reader: &mut (impl Read + Seek), n_bytes: usize) -> NitfResult<()> {
        self.size = n_bytes;
        self.tre = vec![0; n_bytes];
        trace!("Reading: {}", self.name);
        reader
            .read_exact(self.tre.as_mut_slice())
            .map_err(NitfError::IOError)
    }
    pub fn write(&self, writer: &mut (impl Write + Seek)) -> NitfResult<usize> {
        trace!("Writing: {}", self.name);
        writer
            .write(self.tre.as_slice())
            .map_err(NitfError::IOError)
    }
}
impl Display for ExtendedSubheader {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        // Can't copy vector directly, convert to slice, then clone into new vector
        let out_str = String::from_utf8(self.tre.to_vec()).or(Err(std::fmt::Error))?;
        write!(f, "{}: [{out_str}], ", self.name)
    }
}