nu_plugin_dcm 0.2.2

use std::io::Cursor;
use std::path::{Path, PathBuf};

use crate::meta::make_row_from_dicom_metadata;
use crate::reader::{read_dcm_file, read_dcm_stream};

use crate::dcm;
use dicom::object::DefaultDicomObject;
use dicom::object::StandardDataDictionary;
use indexmap::IndexMap;
use nu_plugin::{EngineInterface, Plugin, PluginCommand};
use nu_protocol::ast::CellPath;
use nu_protocol::{
    Category, Example, LabeledError, PipelineData, Record, ShellError, Signature, Span,
    SyntaxShape, Value,
};

#[derive(Default)]
pub struct DcmPlugin {
    pub dcm_dictionary: StandardDataDictionary,
}

impl Plugin for DcmPlugin {
    fn version(&self) -> String {
        env!("CARGO_PKG_VERSION").to_string()
    }

    fn commands(&self) -> Vec<Box<dyn nu_plugin::PluginCommand<Plugin = Self>>> {
        vec![Box::new(DcmPluginCommand)]
    }
}

#[derive(Default)]
pub struct DcmPluginCommand;

impl PluginCommand for DcmPluginCommand {
    type Plugin = DcmPlugin;

    fn name(&self) -> &str {
        "dcm"
    }

    fn description(&self) -> &str {
        "Parse DICOM object from file or binary data. Invalid DICOM objects are reported as errors and excluded from the output."
    }

    fn signature(&self) -> Signature {
        /*
        // Some example DICOM fields
        let dicom_record_fields = vec![
            ("StudyInstanceUID".to_string(), Type::String),
            ("StudyDate".to_string(), Type::String),
            ("Modality".to_string(), Type::Float),
            (
                "PixelSpacing".to_string(),
                Type::List(Box::new(Type::Float)),
            ),
            ("...".to_string(), Type::Any),
        ];

        let file_record_fields = vec![
            ("name".to_string(), Type::String),
            ("type".to_string(), Type::String),
        ];

        let dicom_record_type = Type::Record(dicom_record_fields.into_boxed_slice());
        let file_record_type = Type::Record(file_record_fields.into_boxed_slice());
        */

        Signature::build(nu_plugin::PluginCommand::name(self))
            // TODO is it possible to specify all input/output types? The plugin is very
            // dynamic and e.g. `echo file.dcm | wrap foo | dcm foo` failed the type check...
            /*
            .input_output_types(
                vec![
                    // String (filename) -> Record (DICOM data)
                    (Type::String, dicom_record_type.clone()),
                    // Binary (DICOM data) -> Record (DICOM data)
                    (Type::Binary, dicom_record_type.clone()),
                    // Record (file data) -> Record (DICOM data)
                    (file_record_type.clone(), dicom_record_type.clone()),
                    // List of Strings (filenames) -> List of Records
                    (Type::List(Box::new(Type::String)), Type::List(Box::new(dicom_record_type.clone()))),
                    // List of Binary -> List of Records (e.g. [(open 1.dcm), (open 2.dcm)] | dcm)
                    (Type::List(Box::new(Type::Binary)), Type::List(Box::new(dicom_record_type.clone()))),
                    // List of file records) -> List of Records (e.g. `ls *.dcm | dcm name`)
                    (Type::List(Box::new(file_record_type.clone())), Type::List(Box::new(dicom_record_type))),
                ])
              */
            .named(
                "error",
                SyntaxShape::String,
                "If an error occurs when Dicom object is parsed, the error message will be inserted in this column instead producing an error result.",
                Some('e'))
            .optional(
                "column",
                SyntaxShape::CellPath,
                "Optional column name to use as Dicom source",
            )
            .category(Category::Formats)  // More appropriate category
            .search_terms(vec!["dicom".to_string(), "medical".to_string(), "parse".to_string()])
            .description("Parse DICOM files and binary data")
            .extra_description("Parse DICOM objects from files or binary data. Invalid DICOM objects are reported as errors and excluded from the output unless --error flag is used.")
    }

    fn examples(&self) -> Vec<Example> {
        vec![
            Example {
                description: "Parse a DICOM file by passing binary data",
                example: "open file.dcm | dcm",
                result: Some(Value::test_record(Record::from_iter([
                    ("PatientName".to_string(), Value::test_string("John Doe")),
                    ("Modality".to_string(), Value::test_string("CT")),
                    ("StudyDate".to_string(), Value::test_string("20231201")),
                    (
                        "ImageType".to_string(),
                        Value::test_string("ORIGINAL\\PRIMARY"),
                    ),
                ]))),
            },
            Example {
                description: "Parse DICOM files from a list",
                example: "ls *.dcm | dcm name",
                result: None,
            },
            Example {
                description: "Parse a specific file by filename",
                example: "\"file.dcm\" | dcm",
                result: None,
            },
            Example {
                description: "Parse with error handling",
                example: "ls *.dcm | dcm name --error parse_error",
                result: None,
            },
        ]
    }

    fn run(
        &self,
        plugin: &DcmPlugin,
        engine: &EngineInterface,
        call: &nu_plugin::EvaluatedCall,
        input: PipelineData,
    ) -> Result<PipelineData, LabeledError> {
        let current_dir = engine.get_current_dir().map(PathBuf::from);

        let span = input.span().unwrap_or(call.head);
        let input_metadata = input.metadata();

        // Convert input PipelineData to Value. The default behaviour for BinaryStream is to detect the type of the stream and if unknown, try to read it as a UTF-8 string.
        // This behaviour is wrong for us, since we want to read any binary input stream as binary data.
        // Unfortunately, a list of `[(`open file.dcm`), ...]` gets converted to a list of strings by nushell before we can access it.
        let input = if let PipelineData::ByteStream(byte_stream, ..) = input {
            // TODO eventually support streaming?
            let bytes = byte_stream.into_bytes()?;
            Value::binary(bytes, span)
        } else {
            // convert PipelineData to Value the usual way
            input.into_value(span)?
        };

        // parse args, nu makes sure the num of args and type is correct
        let source_column = call.nth(0);
        let source_column = if let Some(Value::CellPath { val, .. }) = source_column {
            Some(val)
        } else {
            None
        };

        let error_column = call.get_flag_value("error");
        let error_column = if let Some(Value::String { val, .. }) = error_column {
            Some(val)
        } else {
            None
        };

        // run
        let output = self.run_filter(
            plugin,
            current_dir.as_deref(),
            &input,
            source_column,
            error_column,
        )?;

        // Forward DataSource metadata from input to output, but clear any content type. This keeps the source.
        let output_metadata = input_metadata.map(|m| m.with_content_type(None));

        Ok(PipelineData::Value(output, output_metadata))
    }
}

impl DcmPluginCommand {
    pub fn run_filter(
        &self,
        plugin: &DcmPlugin,
        current_dir: Result<&Path, &ShellError>,
        value: &Value,
        source_column: Option<CellPath>,
        error_column: Option<String>,
    ) -> Result<Value, LabeledError> {
        // use source column if known
        if let Some(source_column) = source_column {
            // TODO is it possible without cloning?
            let value = value.clone();
            let value = value.follow_cell_path(&source_column.members)?;

            // AFAIK a list, process_value will handle it
            self.process_value(plugin, current_dir, &value, &error_column)
        } else {
            // expect a primitive value if column is not known
            self.process_value(plugin, current_dir, value, &error_column)
        }
    }

    fn process_value(
        &self,
        plugin: &DcmPlugin,
        current_dir: Result<&Path, &ShellError>,
        value: &Value,
        error_column: &Option<String>,
    ) -> Result<Value, LabeledError> {
        let result = self.process_value_with_normal_error(plugin, current_dir, value, error_column);

        // TODO better value.span().unwrap()
        match (error_column, &result) {
            (Some(error_column), Err(err)) => Ok(Value::record(
                Record::from_raw_cols_vals(
                    vec![error_column.to_string()],
                    vec![Value::string(err.msg.to_string(), value.span())],
                    Span::unknown(),
                    Span::unknown(),
                )?,
                value.span(),
            )),
            _ => result,
        }
    }

    fn process_value_with_normal_error(
        &self,
        plugin: &DcmPlugin,
        current_dir: Result<&Path, &ShellError>,
        value: &Value,
        error_column: &Option<String>,
    ) -> Result<Value, LabeledError> {
        match &value {
            Value::String {
                val, internal_span, ..
            } => {
                // make absolute if needed
                let file = resolve_path(val, current_dir, value.span())?;

                // TODO add some heuristics to determine if the input string is filename or DICOM binary data connverted to utf-8 by nu?
                // (see `ByteStream::into_value()` which does the conversion to string.)

                let obj = read_dcm_file(&file).map_err(|e| {
                    // Report a better error if the input string looks like DICOM binary data with preamble.
                    // TODO this is messy. In fact the whole error reporting is messy.
                    let text = if val.get(128..132) == Some("DICM") {
                        "Input string looks like DICOM binary data. Either pass binary data, or a filename.".to_string()
                    } else {
                        format!("{} [file {}]", e, file.to_string_lossy())
                    };

                    LabeledError::new("`dcm` expects valid DICOM binary data").with_label( text, *internal_span)
                })?;

                self.process_dicom_object(plugin, internal_span, obj, error_column)
            }
            Value::Record { val, internal_span } => {
                let record_type = get_record_string(val, "type");
                let record_name = get_record_string(val, "name");

                match (record_type, record_name) {
                    // Probably a file Record
                    (Some("file"), Some(name)) => {
                        Err(LabeledError::new("Cannot process file records directly")
                            .with_help("Extract the filename first using: `dcm name`, `get name | dcm`, or `select name | dcm`")
                            .with_label(
                                format!("Found file record with name: '{}'", name),
                                *internal_span
                            ))
                    }
                    // Output generic record error
                    _ =>  Err(LabeledError::new("Cannot process records directly")
                           .with_label(
                               "Select file name or binary data from the record before passing it to dcm",
                               *internal_span
                           ))
                }
            }
            Value::Binary {
                val, internal_span, ..
            } => {
                let cursor = Cursor::new(val);
                let obj = read_dcm_stream(cursor).map_err(|e| {
                    LabeledError::new("Invalid DICOM data")
                        .with_label(e.to_string(), *internal_span)
                })?;

                self.process_dicom_object(plugin, internal_span, obj, error_column)
            }
            Value::List {
                vals,
                internal_span,
                ..
            } => {
                // Use either a dicom result or an error for each input element>
                let result: Vec<Value> = vals
                    .iter()
                    .map(|v| {
                        self.process_value(plugin, current_dir, v, error_column)
                            .unwrap_or_else(|e| Value::error(e.into(), *internal_span))
                    })
                    .collect();

                Ok(Value::list(result, *internal_span))
            }
            _ => Err(LabeledError::new("Unrecognized type in stream").with_label(
                "'dcm' expects a string (filepath), binary, or column path",
                value.span(),
            )),
        }
    }

    fn process_dicom_object(
        &self,
        plugin: &DcmPlugin,
        span: &Span,
        obj: DefaultDicomObject,
        error_column: &Option<String>,
    ) -> Result<Value, LabeledError> {
        let dcm_dumper = dcm::DicomDump {
            dcm_dictionary: &plugin.dcm_dictionary,
        };

        let mut index_map = IndexMap::with_capacity(1000);

        // make sure that when --error is used, the column always exists
        if let Some(error_column) = error_column {
            index_map.insert(
                error_column.to_string(),
                Value::string(String::new(), *span),
            );
        }

        // dump both metadata and data into a single table
        make_row_from_dicom_metadata(span, &mut index_map, obj.meta());
        dcm_dumper.make_row_from_dicom_object(span, &mut index_map, &obj);

        // convert index map to a record
        Ok(Value::record(Record::from_iter(index_map), *span))
    }
}

fn get_record_string<'a>(record: &'a Record, field_name: &str) -> Option<&'a str> {
    let value = record.get(field_name)?;
    let Value::String { val, .. } = value else {
        return None;
    };
    Some(val.as_str())
}

fn resolve_path(
    filename: &str,
    current_dir: Result<&Path, &ShellError>,
    span: Span,
) -> Result<PathBuf, LabeledError> {
    use std::path::Path;

    let path = Path::new(filename);

    // If path is already absolute, return it as-is
    if path.is_absolute() {
        return Ok(path.to_path_buf());
    }

    // Path is relative, need to resolve against current working directory
    let current_dir = current_dir.map_err(|e| {
        LabeledError::new("Failed to get current working directory").with_label(
            format!(
                "Cannot resolve relative path '{}'\n\nError: {}",
                filename, e
            ),
            span,
        )
    })?;

    Ok(PathBuf::from(current_dir).join(filename))
}