work

[pspp] / rust / src / cooked.rs

use std::{borrow::Cow, cmp::Ordering, collections::HashMap, iter::repeat, ops::Range};

use crate::{
    encoding::{default_encoding, get_encoding, Error as EncodingError},
    endian::Endian,
    format::{Error as FormatError, Spec, UncheckedSpec},
    identifier::{Error as IdError, Identifier},
    raw::{self, UnencodedStr, VarType},
};
use chrono::{NaiveDate, NaiveDateTime, NaiveTime};
use encoding_rs::{DecoderResult, Encoding};
use num::integer::div_ceil;
use ordered_float::OrderedFloat;
use thiserror::Error as ThisError;

pub use crate::raw::{CategoryLabels, Compression};

#[derive(ThisError, Debug)]
pub enum Error {
    // XXX this is really an internal error and maybe we should change the
    // interfaces to make it impossible
    #[error("Missing header record")]
    MissingHeaderRecord,

    #[error("{0}")]
    EncodingError(EncodingError),

    #[error("Using default encoding {0}.")]
    UsingDefaultEncoding(String),

    #[error("Variable record from offset {:x} to {:x} specifies width {width} not in valid range [-1,255).", offsets.start, offsets.end)]
    InvalidVariableWidth { offsets: Range<u64>, width: i32 },

    #[error("This file has corrupted metadata written by a buggy version of PSPP.  To ensure that other software can read it correctly, save a new copy of the file.")]
    InvalidLongMissingValueFormat,

    #[error("File creation date {creation_date} is not in the expected format \"DD MMM YY\" format.  Using 01 Jan 1970.")]
    InvalidCreationDate { creation_date: String },

    #[error("File creation time {creation_time} is not in the expected format \"HH:MM:SS\" format.  Using midnight.")]
    InvalidCreationTime { creation_time: String },

    #[error("{id_error}  Renaming variable to {new_name}.")]
    InvalidVariableName {
        id_error: IdError,
        new_name: Identifier,
    },

    #[error(
        "Substituting {new_spec} for invalid print format on variable {variable}.  {format_error}"
    )]
    InvalidPrintFormat {
        new_spec: Spec,
        variable: Identifier,
        format_error: FormatError,
    },

    #[error(
        "Substituting {new_spec} for invalid write format on variable {variable}.  {format_error}"
    )]
    InvalidWriteFormat {
        new_spec: Spec,
        variable: Identifier,
        format_error: FormatError,
    },

    #[error("Renaming variable with duplicate name {duplicate_name} to {new_name}.")]
    DuplicateVariableName {
        duplicate_name: Identifier,
        new_name: Identifier,
    },

    #[error("Dictionary index {dict_index} is outside valid range [1,{max_index}].")]
    InvalidDictIndex { dict_index: usize, max_index: usize },

    #[error("Dictionary index {0} refers to a long string continuation.")]
    DictIndexIsContinuation(usize),

    #[error("Variables associated with value label are not all of identical type.  Variable {numeric_var} is numeric, but variable {string_var} is string.")]
    ValueLabelsDifferentTypes {
        numeric_var: Identifier,
        string_var: Identifier,
    },

    #[error(
        "Value labels may not be added to long string variable {0} using record types 3 or 4."
    )]
    InvalidLongStringValueLabel(Identifier),

    #[error("Invalid multiple response set name.  {0}")]
    InvalidMrSetName(IdError),

    #[error("Multiple response set {mr_set} includes unknown variable {short_name}.")]
    UnknownMrSetVariable {
        mr_set: Identifier,
        short_name: Identifier,
    },

    #[error("Multiple response set {0} has no variables.")]
    EmptyMrSet(Identifier),

    #[error("Multiple response set {0} has only one variable.")]
    OneVarMrSet(Identifier),

    #[error("Multiple response set {0} contains both string and numeric variables.")]
    MixedMrSet(Identifier),

    #[error(
        "Invalid numeric format for counted value {number} in multiple response set {mr_set}."
    )]
    InvalidMDGroupCountedValue { mr_set: Identifier, number: String },

    #[error("Counted value {value} has width {width}, but it must be no wider than {max_width}, the width of the narrowest variable in multiple response set {mr_set}.")]
    TooWideMDGroupCountedValue {
        mr_set: Identifier,
        value: String,
        width: usize,
        max_width: u16,
    },

    #[error("Long string value label for variable {name} has width {width}, which is not in the valid range [{min_width},{max_width}].")]
    InvalidLongValueLabelWidth {
        name: Identifier,
        width: u32,
        min_width: u16,
        max_width: u16,
    },

    #[error("Invalid attribute name.  {0}")]
    InvalidAttributeName(IdError),

    #[error("Invalid short name in long variable name record.  {0}")]
    InvalidShortName(IdError),

    #[error("Invalid name in long variable name record.  {0}")]
    InvalidLongName(IdError),

    #[error("Invalid variable name in very long string record.  {0}")]
    InvalidLongStringName(IdError),

    #[error("Invalid variable name in long string value label record.  {0}")]
    InvalidLongStringValueLabelName(IdError),

    #[error("Invalid variable name in attribute record.  {0}")]
    InvalidAttributeVariableName(IdError),

    // XXX This is risky because `text` might be arbitarily long.
    #[error("Text string contains invalid bytes for {encoding} encoding: {text}")]
    MalformedString { encoding: String, text: String },

    #[error("Invalid variable measurement level value {0}")]
    InvalidMeasurement(u32),

    #[error("Invalid variable display alignment value {0}")]
    InvalidAlignment(u32),

    #[error("Details TBD")]
    TBD,
}

#[derive(Clone, Debug)]
pub enum Record {
    Header(HeaderRecord),
    Variable(VariableRecord),
    ValueLabel(ValueLabelRecord),
    Document(DocumentRecord),
    IntegerInfo(IntegerInfoRecord),
    FloatInfo(FloatInfoRecord),
    VariableSets(VariableSetRecord),
    VarDisplay(VarDisplayRecord),
    MultipleResponse(MultipleResponseRecord),
    LongStringMissingValues(LongStringMissingValuesRecord),
    LongStringValueLabels(LongStringValueLabelRecord),
    Encoding(EncodingRecord),
    NumberOfCases(NumberOfCasesRecord),
    ProductInfo(ProductInfoRecord),
    LongNames(LongNameRecord),
    VeryLongStrings(VeryLongStringRecord),
    FileAttributes(FileAttributeRecord),
    VariableAttributes(VariableAttributeRecord),
    OtherExtension(Extension),
    //Case(Vec<Value>),
}

pub use crate::raw::EncodingRecord;
pub use crate::raw::Extension;
pub use crate::raw::FloatInfoRecord;
pub use crate::raw::IntegerInfoRecord;
pub use crate::raw::NumberOfCasesRecord;

type DictIndex = usize;

pub struct Variable {
    pub dict_index: DictIndex,
    pub short_name: Identifier,
    pub long_name: Option<Identifier>,
    pub width: VarWidth,
}

pub struct Decoder {
    pub compression: Option<Compression>,
    pub endian: Endian,
    pub encoding: &'static Encoding,
    pub variables: HashMap<DictIndex, Variable>,
    pub var_names: HashMap<Identifier, DictIndex>,
    n_dict_indexes: usize,
    n_generated_names: usize,
}

pub fn decode(
    headers: Vec<raw::Record>,
    encoding: Option<&'static Encoding>,
    warn: &impl Fn(Error),
) -> Result<Vec<Record>, Error> {
    let Some(header_record) = headers.iter().find_map(|rec| {
        if let raw::Record::Header(header) = rec {
            Some(header)
        } else {
            None
        }
    }) else {
        return Err(Error::MissingHeaderRecord);
    };
    let encoding = match encoding {
        Some(encoding) => encoding,
        None => {
            let encoding = headers.iter().find_map(|rec| {
                if let raw::Record::Encoding(ref e) = rec {
                    Some(e.0.as_str())
                } else {
                    None
                }
            });
            let character_code = headers.iter().find_map(|rec| {
                if let raw::Record::IntegerInfo(ref r) = rec {
                    Some(r.character_code)
                } else {
                    None
                }
            });
            match get_encoding(encoding, character_code) {
                Ok(encoding) => encoding,
                Err(err @ EncodingError::Ebcdic) => return Err(Error::EncodingError(err)),
                Err(err) => {
                    warn(Error::EncodingError(err));
                    // Warn that we're using the default encoding.
                    default_encoding()
                }
            }
        }
    };

    let mut decoder = Decoder {
        compression: header_record.compression,
        endian: header_record.endian,
        encoding,
        variables: HashMap::new(),
        var_names: HashMap::new(),
        n_dict_indexes: 0,
        n_generated_names: 0,
    };

    let mut output = Vec::with_capacity(headers.len());
    for header in &headers {
        match header {
            raw::Record::Header(ref input) => {
                if let Some(header) = HeaderRecord::try_decode(&mut decoder, input, warn)? {
                    output.push(Record::Header(header))
                }
            }
            raw::Record::Variable(ref input) => {
                if let Some(variable) = VariableRecord::try_decode(&mut decoder, input, warn)? {
                    output.push(Record::Variable(variable));
                }
            }
            raw::Record::ValueLabel(ref input) => {
                if let Some(value_label) = ValueLabelRecord::try_decode(&mut decoder, input, warn)?
                {
                    output.push(Record::ValueLabel(value_label));
                }
            }
            raw::Record::Document(ref input) => {
                if let Some(document) = DocumentRecord::try_decode(&mut decoder, input, warn)? {
                    output.push(Record::Document(document))
                }
            }
            raw::Record::IntegerInfo(ref input) => output.push(Record::IntegerInfo(input.clone())),
            raw::Record::FloatInfo(ref input) => output.push(Record::FloatInfo(input.clone())),
            raw::Record::VariableSets(ref input) => {
                let s = decoder.decode_string_cow(&input.text.0, warn);
                output.push(Record::VariableSets(VariableSetRecord::parse(&s, warn)?));
            }
            raw::Record::VarDisplay(ref input) => {
                if let Some(vdr) = VarDisplayRecord::try_decode(&mut decoder, input, warn)? {
                    output.push(Record::VarDisplay(vdr))
                }
            }
            raw::Record::MultipleResponse(ref input) => {
                if let Some(mrr) = MultipleResponseRecord::try_decode(&mut decoder, input, warn)? {
                    output.push(Record::MultipleResponse(mrr))
                }
            }
            raw::Record::LongStringMissingValues(ref input) => {
                if let Some(mrr) = LongStringMissingValuesRecord::try_decode(&mut decoder, input, warn)? {
                    output.push(Record::LongStringMissingValues(mrr))
                }
            }
            raw::Record::LongStringValueLabels(ref input) => {
                if let Some(mrr) =
                    LongStringValueLabelRecord::try_decode(&mut decoder, input, warn)?
                {
                    output.push(Record::LongStringValueLabels(mrr))
                }
            }
            raw::Record::Encoding(ref input) => output.push(Record::Encoding(input.clone())),
            raw::Record::NumberOfCases(ref input) => {
                output.push(Record::NumberOfCases(input.clone()))
            }
            raw::Record::ProductInfo(ref input) => {
                let s = decoder.decode_string_cow(&input.text.0, warn);
                output.push(Record::ProductInfo(ProductInfoRecord::parse(&s, warn)?));
            }
            raw::Record::LongNames(ref input) => {
                let s = decoder.decode_string_cow(&input.text.0, warn);
                output.push(Record::LongNames(LongNameRecord::parse(
                    &mut decoder,
                    &s,
                    warn,
                )?));
            }
            raw::Record::VeryLongStrings(ref input) => {
                let s = decoder.decode_string_cow(&input.text.0, warn);
                output.push(Record::VeryLongStrings(VeryLongStringRecord::parse(
                    &decoder, &s, warn,
                )?));
            }
            raw::Record::FileAttributes(ref input) => {
                let s = decoder.decode_string_cow(&input.text.0, warn);
                output.push(Record::FileAttributes(FileAttributeRecord::parse(
                    &decoder, &s, warn,
                )?));
            }
            raw::Record::VariableAttributes(ref input) => {
                let s = decoder.decode_string_cow(&input.text.0, warn);
                output.push(Record::VariableAttributes(VariableAttributeRecord::parse(
                    &decoder, &s, warn,
                )?));
            }
            raw::Record::OtherExtension(ref input) => {
                output.push(Record::OtherExtension(input.clone()))
            }
            raw::Record::EndOfHeaders(_) => (),
            raw::Record::ZHeader(_) => (),
            raw::Record::ZTrailer(_) => (),
            raw::Record::Cases(_) => (),
        };
    }
    Ok(output)
}

impl Decoder {
    fn generate_name(&mut self) -> Identifier {
        loop {
            self.n_generated_names += 1;
            let name = Identifier::new(&format!("VAR{:03}", self.n_generated_names), self.encoding)
                .unwrap();
            if !self.var_names.contains_key(&name) {
                return name;
            }
            assert!(self.n_generated_names < usize::MAX);
        }
    }
    fn decode_string_cow<'a>(&self, input: &'a [u8], warn: &impl Fn(Error)) -> Cow<'a, str> {
        let (output, malformed) = self.encoding.decode_without_bom_handling(input);
        if malformed {
            warn(Error::MalformedString {
                encoding: self.encoding.name().into(),
                text: output.clone().into(),
            });
        }
        output
    }
    fn decode_string(&self, input: &[u8], warn: &impl Fn(Error)) -> String {
        self.decode_string_cow(input, warn).into()
    }
    pub fn decode_identifier(
        &self,
        input: &[u8],
        warn: &impl Fn(Error),
    ) -> Result<Identifier, IdError> {
        let s = self.decode_string_cow(input, warn);
        Identifier::new(&s, self.encoding)
    }
    fn get_var_by_index(&self, dict_index: usize) -> Result<&Variable, Error> {
        let max_index = self.n_dict_indexes;
        if dict_index == 0 || dict_index > max_index {
            return Err(Error::InvalidDictIndex {
                dict_index,
                max_index,
            });
        }
        let Some(variable) = self.variables.get(&(dict_index - 1)) else {
            return Err(Error::DictIndexIsContinuation(dict_index));
        };
        Ok(variable)
    }

    /// Returns `input` decoded from `self.encoding` into UTF-8 such that
    /// re-encoding the result back into `self.encoding` will have exactly the
    /// same length in bytes.
    ///
    /// XXX warn about errors?
    fn decode_exact_length<'a>(&self, input: &'a [u8]) -> Cow<'a, str> {
        if let (s, false) = self.encoding.decode_without_bom_handling(input) {
            // This is the common case.  Usually there will be no errors.
            s
        } else {
            // Unusual case.  Don't bother to optimize it much.
            let mut decoder = self.encoding.new_decoder_without_bom_handling();
            let mut output = String::with_capacity(
                decoder
                    .max_utf8_buffer_length_without_replacement(input.len())
                    .unwrap(),
            );
            let mut rest = input;
            while !rest.is_empty() {
                match decoder.decode_to_string_without_replacement(rest, &mut output, true) {
                    (DecoderResult::InputEmpty, _) => break,
                    (DecoderResult::OutputFull, _) => unreachable!(),
                    (DecoderResult::Malformed(a, b), consumed) => {
                        let skipped = a as usize + b as usize;
                        output.extend(repeat('?').take(skipped));
                        rest = &rest[consumed..];
                    }
                }
            }
            assert_eq!(self.encoding.encode(&output).0.len(), input.len());
            output.into()
        }
    }
}

pub trait TryDecode: Sized {
    type Input;
    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error>;
}

pub trait Decode<Input>: Sized {
    fn decode(decoder: &Decoder, input: &Input, warn: impl Fn(Error)) -> Self;
}

impl<const N: usize> Decode<UnencodedStr<N>> for String {
    fn decode(decoder: &Decoder, input: &UnencodedStr<N>, warn: impl Fn(Error)) -> Self {
        decoder.decode_string(&input.0, &warn)
    }
}

#[derive(Clone, Debug)]
pub struct HeaderRecord {
    pub eye_catcher: String,
    pub weight_index: Option<usize>,
    pub n_cases: Option<u64>,
    pub creation: NaiveDateTime,
    pub file_label: String,
}

fn trim_end_spaces(mut s: String) -> String {
    s.truncate(s.trim_end_matches(' ').len());
    s
}

impl TryDecode for HeaderRecord {
    type Input = crate::raw::HeaderRecord;

    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error> {
        let eye_catcher = trim_end_spaces(decoder.decode_string(&input.eye_catcher.0, &warn));
        let file_label = trim_end_spaces(decoder.decode_string(&input.file_label.0, &warn));
        let creation_date = decoder.decode_string_cow(&input.creation_date.0, &warn);
        let creation_date =
            NaiveDate::parse_from_str(&creation_date, "%e %b %Y").unwrap_or_else(|_| {
                warn(Error::InvalidCreationDate {
                    creation_date: creation_date.into(),
                });
                Default::default()
            });
        let creation_time = decoder.decode_string_cow(&input.creation_time.0, &warn);
        let creation_time =
            NaiveTime::parse_from_str(&creation_time, "%H:%M:%S").unwrap_or_else(|_| {
                warn(Error::InvalidCreationTime {
                    creation_time: creation_time.into(),
                });
                Default::default()
            });
        Ok(Some(HeaderRecord {
            eye_catcher,
            weight_index: input.weight_index.map(|n| n as usize),
            n_cases: input.n_cases.map(|n| n as u64),
            creation: NaiveDateTime::new(creation_date, creation_time),
            file_label,
        }))
    }
}

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum VarWidth {
    Numeric,
    String(u16),
}

impl PartialOrd for VarWidth {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        match (self, other) {
            (VarWidth::Numeric, VarWidth::Numeric) => Some(Ordering::Equal),
            (VarWidth::String(a), VarWidth::String(b)) => Some(a.cmp(b)),
            _ => None,
        }
    }
}

impl VarWidth {
    const MAX_STRING: u16 = 32767;

    fn n_dict_indexes(self) -> usize {
        match self {
            VarWidth::Numeric => 1,
            VarWidth::String(w) => div_ceil(w as usize, 8),
        }
    }

    fn width_predicate(
        a: Option<VarWidth>,
        b: Option<VarWidth>,
        f: impl Fn(u16, u16) -> u16,
    ) -> Option<VarWidth> {
        match (a, b) {
            (Some(VarWidth::Numeric), Some(VarWidth::Numeric)) => Some(VarWidth::Numeric),
            (Some(VarWidth::String(a)), Some(VarWidth::String(b))) => {
                Some(VarWidth::String(f(a, b)))
            }
            _ => None,
        }
    }

    /// Returns the wider of `self` and `other`:
    /// - Numerical variable widths are equally wide.
    /// - Longer strings are wider than shorter strings.
    /// - Numerical and string types are incomparable, so result in `None`.
    /// - Any `None` in the input yields `None` in the output.
    pub fn wider(a: Option<VarWidth>, b: Option<VarWidth>) -> Option<VarWidth> {
        Self::width_predicate(a, b, |a, b| a.max(b))
    }

    /// Returns the narrower of `self` and `other` (see [`Self::wider`]).
    pub fn narrower(a: Option<VarWidth>, b: Option<VarWidth>) -> Option<VarWidth> {
        Self::width_predicate(a, b, |a, b| a.min(b))
    }
}

impl From<VarWidth> for VarType {
    fn from(source: VarWidth) -> Self {
        match source {
            VarWidth::Numeric => VarType::Numeric,
            VarWidth::String(_) => VarType::String,
        }
    }
}

#[derive(Clone, Debug)]
pub struct VariableRecord {
    pub width: VarWidth,
    pub name: Identifier,
    pub print_format: Spec,
    pub write_format: Spec,
    pub missing_values: MissingValues,
    pub label: Option<String>,
}

#[derive(Clone, Debug)]
pub struct MissingValues {
    /// Individual missing values, up to 3 of them.
    pub values: Vec<Value>,

    /// Optional range of missing values.
    pub range: Option<(Value, Value)>,
}

impl Decode<raw::MissingValues> for MissingValues {
    fn decode(decoder: &Decoder, input: &raw::MissingValues, _warn: impl Fn(Error)) -> Self {
        MissingValues {
            values: input
                .values
                .iter()
                .map(|value| Value::decode(value, decoder))
                .collect(),
            range: input
                .range
                .as_ref()
                .map(|(low, high)| (Value::decode(low, decoder), Value::decode(high, decoder))),
        }
    }
}

fn decode_format(raw: raw::Spec, width: VarWidth, warn: impl Fn(Spec, FormatError)) -> Spec {
    UncheckedSpec::try_from(raw)
        .and_then(Spec::try_from)
        .and_then(|x| x.check_width_compatibility(width))
        .unwrap_or_else(|error| {
            let new_format = Spec::default_for_width(width);
            warn(new_format, error);
            new_format
        })
}

impl TryDecode for VariableRecord {
    type Input = raw::VariableRecord;

    fn try_decode(
        decoder: &mut Decoder,
        input: &crate::raw::VariableRecord,
        warn: impl Fn(Error),
    ) -> Result<Option<VariableRecord>, Error> {
        let width = match input.width {
            0 => VarWidth::Numeric,
            w @ 1..=255 => VarWidth::String(w as u16),
            -1 => return Ok(None),
            _ => {
                return Err(Error::InvalidVariableWidth {
                    offsets: input.offsets.clone(),
                    width: input.width,
                })
            }
        };
        let name = trim_end_spaces(decoder.decode_string(&input.name.0, &warn));
        let name = match Identifier::new(&name, decoder.encoding) {
            Ok(name) => {
                if !decoder.var_names.contains_key(&name) {
                    name
                } else {
                    let new_name = decoder.generate_name();
                    warn(Error::DuplicateVariableName {
                        duplicate_name: name.clone(),
                        new_name: new_name.clone(),
                    });
                    new_name
                }
            }
            Err(id_error) => {
                let new_name = decoder.generate_name();
                warn(Error::InvalidVariableName {
                    id_error,
                    new_name: new_name.clone(),
                });
                new_name
            }
        };
        let variable = Variable {
            dict_index: decoder.n_dict_indexes,
            short_name: name.clone(),
            long_name: None,
            width,
        };
        decoder.n_dict_indexes += width.n_dict_indexes();
        assert!(decoder
            .var_names
            .insert(name.clone(), variable.dict_index)
            .is_none());
        assert!(decoder
            .variables
            .insert(variable.dict_index, variable)
            .is_none());

        let print_format = decode_format(input.print_format, width, |new_spec, format_error| {
            warn(Error::InvalidPrintFormat {
                new_spec,
                variable: name.clone(),
                format_error,
            })
        });
        let write_format = decode_format(input.write_format, width, |new_spec, format_error| {
            warn(Error::InvalidWriteFormat {
                new_spec,
                variable: name.clone(),
                format_error,
            })
        });
        let label = input
            .label
            .as_ref()
            .map(|label| decoder.decode_string(&label.0, &warn));
        Ok(Some(VariableRecord {
            width,
            name,
            print_format,
            write_format,
            missing_values: MissingValues::decode(decoder, &input.missing_values, warn),
            label,
        }))
    }
}

#[derive(Clone, Debug)]
pub struct DocumentRecord(Vec<String>);

impl TryDecode for DocumentRecord {
    type Input = crate::raw::DocumentRecord;

    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error> {
        Ok(Some(DocumentRecord(
            input
                .lines
                .iter()
                .map(|s| trim_end_spaces(decoder.decode_string(&s.0, &warn)))
                .collect(),
        )))
    }
}

trait TextRecord
where
    Self: Sized,
{
    const NAME: &'static str;
    fn parse(input: &str, warn: impl Fn(Error)) -> Result<Self, Error>;
}

#[derive(Clone, Debug)]
pub struct VariableSet {
    pub name: String,
    pub vars: Vec<String>,
}

impl VariableSet {
    fn parse(input: &str) -> Result<Self, Error> {
        let (name, input) = input.split_once('=').ok_or(Error::TBD)?;
        let vars = input.split_ascii_whitespace().map(String::from).collect();
        Ok(VariableSet {
            name: name.into(),
            vars,
        })
    }
}

trait WarnOnError<T> {
    fn warn_on_error<F: Fn(Error)>(self, warn: &F) -> Option<T>;
}
impl<T> WarnOnError<T> for Result<T, Error> {
    fn warn_on_error<F: Fn(Error)>(self, warn: &F) -> Option<T> {
        match self {
            Ok(result) => Some(result),
            Err(error) => {
                warn(error);
                None
            }
        }
    }
}

#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Value {
    Number(Option<OrderedFloat<f64>>),
    String(String),
}

impl Value {
    pub fn decode(raw: &raw::Value, decoder: &Decoder) -> Self {
        match raw {
            raw::Value::Number(x) => Value::Number(x.map(|x| x.into())),
            raw::Value::String(s) => Value::String(decoder.decode_exact_length(&s.0).into()),
        }
    }
}

#[derive(Clone, Debug)]
pub struct ValueLabel {
    pub value: Value,
    pub label: String,
}

#[derive(Clone, Debug)]
pub struct ValueLabelRecord {
    pub var_type: VarType,
    pub labels: Vec<ValueLabel>,
    pub variables: Vec<Identifier>,
}

impl TryDecode for ValueLabelRecord {
    type Input = crate::raw::ValueLabelRecord;
    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<ValueLabelRecord>, Error> {
        let variables: Vec<&Variable> = input
            .dict_indexes
            .iter()
            .filter_map(|&dict_index| {
                decoder
                    .get_var_by_index(dict_index as usize)
                    .warn_on_error(&warn)
            })
            .filter(|&variable| match variable.width {
                VarWidth::String(width) if width > 8 => {
                    warn(Error::InvalidLongStringValueLabel(
                        variable.short_name.clone(),
                    ));
                    false
                }
                _ => true,
            })
            .collect();
        let mut i = variables.iter();
        let Some(&first_var) = i.next() else {
            return Ok(None);
        };
        let var_type: VarType = first_var.width.into();
        for &variable in i {
            let this_type: VarType = variable.width.into();
            if var_type != this_type {
                let (numeric_var, string_var) = match var_type {
                    VarType::Numeric => (first_var, variable),
                    VarType::String => (variable, first_var),
                };
                warn(Error::ValueLabelsDifferentTypes {
                    numeric_var: numeric_var.short_name.clone(),
                    string_var: string_var.short_name.clone(),
                });
                return Ok(None);
            }
        }
        let labels = input
            .labels
            .iter()
            .map(|(value, label)| {
                let label = decoder.decode_string(&label.0, &warn);
                let value = Value::decode(
                    &raw::Value::from_raw(value, var_type, decoder.endian),
                    decoder,
                );
                ValueLabel { value, label }
            })
            .collect();
        let variables = variables
            .iter()
            .map(|&variable| variable.short_name.clone())
            .collect();
        Ok(Some(ValueLabelRecord {
            var_type,
            labels,
            variables,
        }))
    }
}

#[derive(Clone, Debug)]
pub struct VariableSetRecord(Vec<VariableSet>);

impl TextRecord for VariableSetRecord {
    const NAME: &'static str = "variable set";
    fn parse(input: &str, warn: impl Fn(Error)) -> Result<Self, Error> {
        let mut sets = Vec::new();
        for line in input.lines() {
            if let Some(set) = VariableSet::parse(line).warn_on_error(&warn) {
                sets.push(set)
            }
        }
        Ok(VariableSetRecord(sets))
    }
}

#[derive(Clone, Debug)]
pub struct ProductInfoRecord(pub String);

impl TextRecord for ProductInfoRecord {
    const NAME: &'static str = "extra product info";
    fn parse(input: &str, _warn: impl Fn(Error)) -> Result<Self, Error> {
        Ok(ProductInfoRecord(input.into()))
    }
}

#[derive(Clone, Debug)]
pub struct LongName {
    pub short_name: Identifier,
    pub long_name: Identifier,
}

impl LongName {
    fn new(decoder: &mut Decoder, short_name: &str, long_name: &str) -> Result<LongName, Error> {
        let short_name =
            Identifier::new(short_name, decoder.encoding).map_err(Error::InvalidShortName)?;
        let long_name =
            Identifier::new(long_name, decoder.encoding).map_err(Error::InvalidLongName)?;
        Ok(LongName {
            short_name,
            long_name,
        })
    }
}

#[derive(Clone, Debug)]
pub struct LongNameRecord(Vec<LongName>);

impl LongNameRecord {
    pub fn parse(decoder: &mut Decoder, input: &str, warn: impl Fn(Error)) -> Result<Self, Error> {
        let mut names = Vec::new();
        for pair in input.split('\t').filter(|s| !s.is_empty()) {
            if let Some((short_name, long_name)) = pair.split_once('=') {
                if let Some(long_name) =
                    LongName::new(decoder, short_name, long_name).warn_on_error(&warn)
                {
                    names.push(long_name);
                }
            } else {
                warn(Error::TBD)
            }
        }
        Ok(LongNameRecord(names))
    }
}

#[derive(Clone, Debug)]
pub struct VeryLongString {
    pub short_name: Identifier,
    pub length: u16,
}

impl VeryLongString {
    fn parse(decoder: &Decoder, input: &str) -> Result<VeryLongString, Error> {
        let Some((short_name, length)) = input.split_once('=') else {
            return Err(Error::TBD);
        };
        let short_name =
            Identifier::new(short_name, decoder.encoding).map_err(Error::InvalidLongStringName)?;
        let length: u16 = length.parse().map_err(|_| Error::TBD)?;
        if length > VarWidth::MAX_STRING {
            return Err(Error::TBD);
        }
        Ok(VeryLongString { short_name, length })
    }
}

#[derive(Clone, Debug)]
pub struct VeryLongStringRecord(Vec<VeryLongString>);

impl VeryLongStringRecord {
    pub fn parse(decoder: &Decoder, input: &str, warn: impl Fn(Error)) -> Result<Self, Error> {
        let mut very_long_strings = Vec::new();
        for tuple in input
            .split('\0')
            .map(|s| s.trim_end_matches('\t'))
            .filter(|s| !s.is_empty())
        {
            if let Some(vls) = VeryLongString::parse(decoder, tuple).warn_on_error(&warn) {
                very_long_strings.push(vls)
            }
        }
        Ok(VeryLongStringRecord(very_long_strings))
    }
}

#[derive(Clone, Debug)]
pub struct Attribute {
    pub name: Identifier,
    pub values: Vec<String>,
}

impl Attribute {
    fn parse<'a>(
        decoder: &Decoder,
        input: &'a str,
        warn: &impl Fn(Error),
    ) -> Result<(Option<Attribute>, &'a str), Error> {
        let Some((name, mut input)) = input.split_once('(') else {
            return Err(Error::TBD);
        };
        let mut values = Vec::new();
        loop {
            let Some((value, rest)) = input.split_once('\n') else {
                return Err(Error::TBD);
            };
            if let Some(stripped) = value
                .strip_prefix('\'')
                .and_then(|value| value.strip_suffix('\''))
            {
                values.push(stripped.into());
            } else {
                warn(Error::TBD);
                values.push(value.into());
            }
            if let Some(rest) = rest.strip_prefix(')') {
                let attribute = Identifier::new(name, decoder.encoding)
                    .map_err(Error::InvalidAttributeName)
                    .warn_on_error(warn)
                    .map(|name| Attribute { name, values });
                return Ok((attribute, rest));
            };
            input = rest;
        }
    }
}

#[derive(Clone, Debug)]
pub struct AttributeSet(pub Vec<Attribute>);

impl AttributeSet {
    fn parse<'a>(
        decoder: &Decoder,
        mut input: &'a str,
        sentinel: Option<char>,
        warn: &impl Fn(Error),
    ) -> Result<(AttributeSet, &'a str), Error> {
        let mut attributes = Vec::new();
        let rest = loop {
            match input.chars().next() {
                None => break input,
                c if c == sentinel => break &input[1..],
                _ => {
                    let (attribute, rest) = Attribute::parse(decoder, input, &warn)?;
                    if let Some(attribute) = attribute {
                        attributes.push(attribute);
                    }
                    input = rest;
                }
            }
        };
        Ok((AttributeSet(attributes), rest))
    }
}

#[derive(Clone, Debug)]
pub struct FileAttributeRecord(AttributeSet);

impl FileAttributeRecord {
    pub fn parse(decoder: &Decoder, input: &str, warn: impl Fn(Error)) -> Result<Self, Error> {
        let (set, rest) = AttributeSet::parse(decoder, input, None, &warn)?;
        if !rest.is_empty() {
            warn(Error::TBD);
        }
        Ok(FileAttributeRecord(set))
    }
}

#[derive(Clone, Debug)]
pub struct VarAttributeSet {
    pub long_var_name: Identifier,
    pub attributes: AttributeSet,
}

impl VarAttributeSet {
    fn parse<'a>(
        decoder: &Decoder,
        input: &'a str,
        warn: &impl Fn(Error),
    ) -> Result<(Option<VarAttributeSet>, &'a str), Error> {
        let Some((long_var_name, rest)) = input.split_once(':') else {
            return Err(Error::TBD);
        };
        let (attributes, rest) = AttributeSet::parse(decoder, rest, Some('/'), warn)?;
        let var_attribute = Identifier::new(long_var_name, decoder.encoding)
            .map_err(Error::InvalidAttributeVariableName)
            .warn_on_error(warn)
            .map(|name| VarAttributeSet {
                long_var_name: name,
                attributes,
            });
        Ok((var_attribute, rest))
    }
}

#[derive(Clone, Debug)]
pub struct VariableAttributeRecord(Vec<VarAttributeSet>);

impl VariableAttributeRecord {
    pub fn parse(decoder: &Decoder, mut input: &str, warn: impl Fn(Error)) -> Result<Self, Error> {
        let mut var_attribute_sets = Vec::new();
        while !input.is_empty() {
            let Some((var_attribute, rest)) =
                VarAttributeSet::parse(decoder, input, &warn).warn_on_error(&warn)
            else {
                break;
            };
            if let Some(var_attribute) = var_attribute {
                var_attribute_sets.push(var_attribute);
            }
            input = rest;
        }
        Ok(VariableAttributeRecord(var_attribute_sets))
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Measure {
    Nominal,
    Ordinal,
    Scale,
}

impl Measure {
    fn try_decode(source: u32) -> Result<Option<Measure>, Error> {
        match source {
            0 => Ok(None),
            1 => Ok(Some(Measure::Nominal)),
            2 => Ok(Some(Measure::Ordinal)),
            3 => Ok(Some(Measure::Scale)),
            _ => Err(Error::InvalidMeasurement(source)),
        }
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Alignment {
    Left,
    Right,
    Center,
}

impl Alignment {
    fn try_decode(source: u32) -> Result<Option<Alignment>, Error> {
        match source {
            0 => Ok(None),
            1 => Ok(Some(Alignment::Left)),
            2 => Ok(Some(Alignment::Right)),
            3 => Ok(Some(Alignment::Center)),
            _ => Err(Error::InvalidAlignment(source)),
        }
    }
}

#[derive(Clone, Debug)]
pub struct VarDisplay {
    pub measure: Option<Measure>,
    pub width: Option<u32>,
    pub alignment: Option<Alignment>,
}

#[derive(Clone, Debug)]
pub struct VarDisplayRecord(pub Vec<VarDisplay>);

impl TryDecode for VarDisplayRecord {
    type Input = raw::VarDisplayRecord;
    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error> {
        let n_vars = decoder.variables.len();
        let n_per_var = if input.0.len() == 3 * n_vars {
            3
        } else if input.0.len() == 2 * n_vars {
            2
        } else {
            return Err(Error::TBD);
        };

        let var_displays = input
            .0
            .chunks(n_per_var)
            .map(|chunk| {
                let (measure, width, alignment) = match n_per_var == 3 {
                    true => (chunk[0], Some(chunk[1]), chunk[2]),
                    false => (chunk[0], None, chunk[1]),
                };
                let measure = Measure::try_decode(measure).warn_on_error(&warn).flatten();
                let alignment = Alignment::try_decode(alignment)
                    .warn_on_error(&warn)
                    .flatten();
                VarDisplay {
                    measure,
                    width,
                    alignment,
                }
            })
            .collect();
        Ok(Some(VarDisplayRecord(var_displays)))
    }
}

#[derive(Clone, Debug)]
pub enum MultipleResponseType {
    MultipleDichotomy {
        value: Value,
        labels: CategoryLabels,
    },
    MultipleCategory,
}

impl MultipleResponseType {
    fn decode(
        decoder: &Decoder,
        mr_set: &Identifier,
        input: &raw::MultipleResponseType,
        min_width: VarWidth,
        warn: &impl Fn(Error),
    ) -> Result<Self, Error> {
        let mr_type = match input {
            raw::MultipleResponseType::MultipleDichotomy { value, labels } => {
                let value = decoder.decode_string_cow(&value.0, warn);
                let value = match min_width {
                    VarWidth::Numeric => {
                        let number: f64 = value.trim().parse().map_err(|_| {
                            Error::InvalidMDGroupCountedValue {
                                mr_set: mr_set.clone(),
                                number: value.into(),
                            }
                        })?;
                        Value::Number(Some(number.into()))
                    }
                    VarWidth::String(max_width) => {
                        let value = value.trim_end_matches(' ');
                        let width = value.len();
                        if width > max_width as usize {
                            return Err(Error::TooWideMDGroupCountedValue {
                                mr_set: mr_set.clone(),
                                value: value.into(),
                                width,
                                max_width,
                            });
                        };
                        Value::String(value.into())
                    }
                };
                MultipleResponseType::MultipleDichotomy {
                    value,
                    labels: *labels,
                }
            }
            raw::MultipleResponseType::MultipleCategory => MultipleResponseType::MultipleCategory,
        };
        Ok(mr_type)
    }
}

#[derive(Clone, Debug)]
pub struct MultipleResponseSet {
    pub name: Identifier,
    pub min_width: VarWidth,
    pub max_width: VarWidth,
    pub label: String,
    pub mr_type: MultipleResponseType,
    pub dict_indexes: Vec<DictIndex>,
}

impl MultipleResponseSet {
    fn decode(
        decoder: &Decoder,
        input: &raw::MultipleResponseSet,
        warn: &impl Fn(Error),
    ) -> Result<Self, Error> {
        let mr_set_name = decoder
            .decode_identifier(&input.name.0, warn)
            .map_err(Error::InvalidMrSetName)?;

        let label = decoder.decode_string(&input.label.0, warn);

        let mut dict_indexes = Vec::with_capacity(input.short_names.len());
        for short_name in input.short_names.iter() {
            let short_name = match decoder.decode_identifier(&short_name.0, warn) {
                Ok(name) => name,
                Err(error) => {
                    warn(Error::InvalidMrSetName(error));
                    continue;
                }
            };
            let Some(&dict_index) = decoder.var_names.get(&short_name) else {
                warn(Error::UnknownMrSetVariable {
                    mr_set: mr_set_name.clone(),
                    short_name: short_name.clone(),
                });
                continue;
            };
            dict_indexes.push(dict_index);
        }

        match dict_indexes.len() {
            0 => return Err(Error::EmptyMrSet(mr_set_name)),
            1 => return Err(Error::OneVarMrSet(mr_set_name)),
            _ => (),
        }

        let Some((Some(min_width), Some(max_width))) = dict_indexes
            .iter()
            .map(|dict_index| decoder.variables[dict_index].width)
            .map(|w| (Some(w), Some(w)))
            .reduce(|(na, wa), (nb, wb)| (VarWidth::narrower(na, nb), VarWidth::wider(wa, wb)))
        else {
            return Err(Error::MixedMrSet(mr_set_name));
        };

        let mr_type =
            MultipleResponseType::decode(decoder, &mr_set_name, &input.mr_type, min_width, warn)?;

        Ok(MultipleResponseSet {
            name: mr_set_name,
            min_width,
            max_width,
            label,
            mr_type,
            dict_indexes,
        })
    }
}

#[derive(Clone, Debug)]
pub struct MultipleResponseRecord(pub Vec<MultipleResponseSet>);

impl TryDecode for MultipleResponseRecord {
    type Input = raw::MultipleResponseRecord;

    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error> {
        let mut sets = Vec::with_capacity(input.0.len());
        for set in &input.0 {
            match MultipleResponseSet::decode(decoder, set, &warn) {
                Ok(set) => sets.push(set),
                Err(error) => warn(error),
            }
        }
        Ok(Some(MultipleResponseRecord(sets)))
    }
}

#[derive(Clone, Debug)]
pub struct LongStringMissingValues {
    /// Variable name.
    pub var_name: Identifier,

    /// Missing values.
    pub missing_values: MissingValues,
}

impl LongStringMissingValues {
    fn decode(
        decoder: &Decoder,
        input: &raw::LongStringMissingValues,
        warn: &impl Fn(Error),
    ) -> Result<Self, Error> {
        let var_name = decoder.decode_string(&input.var_name.0, warn);
        let var_name = Identifier::new(var_name.trim_end(), decoder.encoding)
            .map_err(Error::InvalidLongStringValueLabelName)?;

        let missing_values = MissingValues::decode(decoder, &input.missing_values, warn);

        Ok(LongStringMissingValues {
            var_name,
            missing_values
        })
    }
}

#[derive(Clone, Debug)]
pub struct LongStringMissingValuesRecord(Vec<LongStringMissingValues>);

impl TryDecode for LongStringMissingValuesRecord {
    type Input = raw::LongStringMissingValueSet;

    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error> {
        let mut labels = Vec::with_capacity(input.0.len());
        for label in &input.0 {
            match LongStringMissingValues::decode(decoder, label, &warn) {
                Ok(set) => labels.push(set),
                Err(error) => warn(error),
            }
        }
        Ok(Some(LongStringMissingValuesRecord(labels)))
    }
}

#[derive(Clone, Debug)]
pub struct LongStringValueLabels {
    pub var_name: Identifier,
    pub width: VarWidth,
    pub labels: Vec<ValueLabel>,
}

impl LongStringValueLabels {
    fn decode(
        decoder: &Decoder,
        input: &raw::LongStringValueLabels,
        warn: &impl Fn(Error),
    ) -> Result<Self, Error> {
        let var_name = decoder.decode_string(&input.var_name.0, warn);
        let var_name = Identifier::new(var_name.trim_end(), decoder.encoding)
            .map_err(Error::InvalidLongStringValueLabelName)?;

        let min_width = 9;
        let max_width = VarWidth::MAX_STRING;
        if input.width < 9 || input.width > max_width as u32 {
            return Err(Error::InvalidLongValueLabelWidth {
                name: var_name,
                width: input.width,
                min_width,
                max_width,
            });
        }
        let width = input.width as u16;

        let mut labels = Vec::with_capacity(input.labels.len());
        for (value, label) in input.labels.iter() {
            let value = Value::String(decoder.decode_exact_length(&value.0).into());
            let label = decoder.decode_string(&label.0, warn);
            labels.push(ValueLabel { value, label });
        }

        Ok(LongStringValueLabels {
            var_name,
            width: VarWidth::String(width),
            labels,
        })
    }
}

#[derive(Clone, Debug)]
pub struct LongStringValueLabelRecord(pub Vec<LongStringValueLabels>);

impl TryDecode for LongStringValueLabelRecord {
    type Input = raw::LongStringValueLabelRecord;

    fn try_decode(
        decoder: &mut Decoder,
        input: &Self::Input,
        warn: impl Fn(Error),
    ) -> Result<Option<Self>, Error> {
        let mut labels = Vec::with_capacity(input.0.len());
        for label in &input.0 {
            match LongStringValueLabels::decode(decoder, label, &warn) {
                Ok(set) => labels.push(set),
                Err(error) => warn(error),
            }
        }
        Ok(Some(LongStringValueLabelRecord(labels)))
    }
}

#[cfg(test)]
mod test {
    use encoding_rs::WINDOWS_1252;

    #[test]
    fn test() {
        let mut s = String::new();
        s.push(char::REPLACEMENT_CHARACTER);
        let encoded = WINDOWS_1252.encode(&s).0;
        let decoded = WINDOWS_1252.decode(&encoded[..]).0;
        println!("{:?}", decoded);
    }

    #[test]
    fn test2() {
        let charset: Vec<u8> = (0..=255).collect();
        println!("{}", charset.len());
        let decoded = WINDOWS_1252.decode(&charset[..]).0;
        println!("{}", decoded.len());
        let encoded = WINDOWS_1252.encode(&decoded[..]).0;
        println!("{}", encoded.len());
        assert_eq!(&charset[..], &encoded[..]);
    }
}