exiftool_rs/

exiftool.rs

//! Core ExifTool struct and public API.
//!
//! This is the main entry point for reading metadata from files.
//! Mirrors ExifTool.pm's ImageInfo/ExtractInfo/GetInfo pipeline.

use std::collections::HashMap;
use std::fs;
use std::path::Path;

use crate::error::{Error, Result};
use crate::file_type::{self, FileType};
use crate::formats;
use crate::metadata::exif::ByteOrderMark;
use crate::tag::Tag;
use crate::value::Value;
use crate::writer::{exif_writer, iptc_writer, jpeg_writer, matroska_writer, mp4_writer, pdf_writer, png_writer, psd_writer, tiff_writer, webp_writer, xmp_writer};

/// Processing options for metadata extraction.
#[derive(Debug, Clone)]
pub struct Options {
    /// Include duplicate tags (different groups may have same tag name).
    pub duplicates: bool,
    /// Apply print conversions (human-readable values).
    pub print_conv: bool,
    /// Fast scan level: 0=normal, 1=skip composite, 2=skip maker notes, 3=skip thumbnails.
    pub fast_scan: u8,
    /// Only extract these tag names (empty = all).
    pub requested_tags: Vec<String>,
}

impl Default for Options {
    fn default() -> Self {
        Self {
            duplicates: false,
            print_conv: true,
            fast_scan: 0,
            requested_tags: Vec::new(),
        }
    }
}

/// The main ExifTool struct. Create one and use it to extract metadata from files.
///
/// # Example
/// ```no_run
/// use exiftool_rs::ExifTool;
///
/// let mut et = ExifTool::new();
/// let info = et.image_info("photo.jpg").unwrap();
/// for (name, value) in &info {
///     println!("{}: {}", name, value);
/// }
/// ```
/// A queued tag change for writing.
#[derive(Debug, Clone)]
pub struct NewValue {
    /// Tag name (e.g., "Artist", "Copyright", "XMP:Title")
    pub tag: String,
    /// Group prefix if specified (e.g., "EXIF", "XMP", "IPTC")
    pub group: Option<String>,
    /// New value (None = delete tag)
    pub value: Option<String>,
}

/// The main ExifTool engine — read, write, and edit metadata.
///
/// # Reading metadata
/// ```no_run
/// use exiftool_rs::ExifTool;
///
/// let et = ExifTool::new();
///
/// // Full tag structs
/// let tags = et.extract_info("photo.jpg").unwrap();
/// for tag in &tags {
///     println!("[{}] {}: {}", tag.group.family0, tag.name, tag.print_value);
/// }
///
/// // Simple name→value map
/// let info = et.image_info("photo.jpg").unwrap();
/// println!("Camera: {}", info.get("Model").unwrap_or(&String::new()));
/// ```
///
/// # Writing metadata
/// ```no_run
/// use exiftool_rs::ExifTool;
///
/// let mut et = ExifTool::new();
/// et.set_new_value("Artist", Some("John Doe"));
/// et.set_new_value("Copyright", Some("2024"));
/// et.write_info("input.jpg", "output.jpg").unwrap();
/// ```
pub struct ExifTool {
    options: Options,
    new_values: Vec<NewValue>,
}

/// Result of metadata extraction: maps tag names to display values.
pub type ImageInfo = HashMap<String, String>;

impl ExifTool {
    /// Create a new ExifTool instance with default options.
    pub fn new() -> Self {
        Self {
            options: Options::default(),
            new_values: Vec::new(),
        }
    }

    /// Create a new ExifTool instance with custom options.
    pub fn with_options(options: Options) -> Self {
        Self {
            options,
            new_values: Vec::new(),
        }
    }

    /// Get a mutable reference to the options.
    pub fn options_mut(&mut self) -> &mut Options {
        &mut self.options
    }

    /// Get a reference to the options.
    pub fn options(&self) -> &Options {
        &self.options
    }

    // ================================================================
    // Writing API
    // ================================================================

    /// Queue a new tag value for writing.
    ///
    /// Call this one or more times, then call `write_info()` to apply changes.
    ///
    /// # Arguments
    /// * `tag` - Tag name, optionally prefixed with group (e.g., "Artist", "XMP:Title", "EXIF:Copyright")
    /// * `value` - New value, or None to delete the tag
    ///
    /// # Example
    /// ```no_run
    /// use exiftool_rs::ExifTool;
    /// let mut et = ExifTool::new();
    /// et.set_new_value("Artist", Some("John Doe"));
    /// et.set_new_value("Copyright", Some("2024 John Doe"));
    /// et.set_new_value("XMP:Title", Some("My Photo"));
    /// et.write_info("photo.jpg", "photo_out.jpg").unwrap();
    /// ```
    pub fn set_new_value(&mut self, tag: &str, value: Option<&str>) {
        let (group, tag_name) = if let Some(colon_pos) = tag.find(':') {
            (Some(tag[..colon_pos].to_string()), tag[colon_pos + 1..].to_string())
        } else {
            (None, tag.to_string())
        };

        self.new_values.push(NewValue {
            tag: tag_name,
            group,
            value: value.map(|v| v.to_string()),
        });
    }

    /// Clear all queued new values.
    pub fn clear_new_values(&mut self) {
        self.new_values.clear();
    }

    /// Copy tags from a source file, queuing them as new values.
    ///
    /// Reads all tags from `src_path` and queues them for writing.
    /// Optionally filter by tag names.
    pub fn set_new_values_from_file<P: AsRef<Path>>(
        &mut self,
        src_path: P,
        tags_to_copy: Option<&[&str]>,
    ) -> Result<u32> {
        let src_tags = self.extract_info(src_path)?;
        let mut count = 0u32;

        for tag in &src_tags {
            // Skip file-level tags that shouldn't be copied
            if tag.group.family0 == "File" || tag.group.family0 == "Composite" {
                continue;
            }
            // Skip binary/undefined data and empty values
            if tag.print_value.starts_with("(Binary") || tag.print_value.starts_with("(Undefined") {
                continue;
            }
            if tag.print_value.is_empty() {
                continue;
            }

            // Filter by requested tags
            if let Some(filter) = tags_to_copy {
                let name_lower = tag.name.to_lowercase();
                if !filter.iter().any(|f| f.to_lowercase() == name_lower) {
                    continue;
                }
            }

            let _full_tag = format!("{}:{}", tag.group.family0, tag.name);
            self.new_values.push(NewValue {
                tag: tag.name.clone(),
                group: Some(tag.group.family0.clone()),
                value: Some(tag.print_value.clone()),
            });
            count += 1;
        }

        Ok(count)
    }

    /// Set a file's name based on a tag value.
    pub fn set_file_name_from_tag<P: AsRef<Path>>(
        &self,
        path: P,
        tag_name: &str,
        template: &str,
    ) -> Result<String> {
        let path = path.as_ref();
        let tags = self.extract_info(path)?;

        let tag_value = tags
            .iter()
            .find(|t| t.name.to_lowercase() == tag_name.to_lowercase())
            .map(|t| &t.print_value)
            .ok_or_else(|| Error::TagNotFound(tag_name.to_string()))?;

        // Build new filename from template
        // Template: "prefix%value%suffix.ext" or just use the tag value
        let new_name = if template.contains('%') {
            template.replace("%v", value_to_filename(tag_value).as_str())
        } else {
            // Default: use tag value as filename, keep extension
            let ext = path.extension().and_then(|e| e.to_str()).unwrap_or("");
            let clean = value_to_filename(tag_value);
            if ext.is_empty() {
                clean
            } else {
                format!("{}.{}", clean, ext)
            }
        };

        let parent = path.parent().unwrap_or(Path::new(""));
        let new_path = parent.join(&new_name);

        fs::rename(path, &new_path).map_err(Error::Io)?;
        Ok(new_path.to_string_lossy().to_string())
    }

    /// Write queued changes to a file.
    ///
    /// If `dst_path` is the same as `src_path`, the file is modified in-place
    /// (via a temporary file).
    pub fn write_info<P: AsRef<Path>, Q: AsRef<Path>>(&self, src_path: P, dst_path: Q) -> Result<u32> {
        let src_path = src_path.as_ref();
        let dst_path = dst_path.as_ref();
        let data = fs::read(src_path).map_err(Error::Io)?;

        let file_type = self.detect_file_type(&data, src_path)?;
        let output = self.apply_changes(&data, file_type)?;

        // Write to temp file first, then rename (atomic)
        let temp_path = dst_path.with_extension("exiftool_tmp");
        fs::write(&temp_path, &output).map_err(Error::Io)?;
        fs::rename(&temp_path, dst_path).map_err(Error::Io)?;

        Ok(self.new_values.len() as u32)
    }

    /// Apply queued changes to in-memory data.
    fn apply_changes(&self, data: &[u8], file_type: FileType) -> Result<Vec<u8>> {
        match file_type {
            FileType::Jpeg => self.write_jpeg(data),
            FileType::Png => self.write_png(data),
            FileType::Tiff | FileType::Dng | FileType::Cr2 | FileType::Nef
            | FileType::Arw | FileType::Orf | FileType::Pef => self.write_tiff(data),
            FileType::WebP => self.write_webp(data),
            FileType::Mp4 | FileType::QuickTime | FileType::M4a
            | FileType::ThreeGP | FileType::F4v => self.write_mp4(data),
            FileType::Psd => self.write_psd(data),
            FileType::Pdf => self.write_pdf(data),
            FileType::Heif | FileType::Avif => self.write_mp4(data),
            FileType::Mkv | FileType::WebM => self.write_matroska(data),
            FileType::Gif => {
                let comment = self.new_values.iter()
                    .find(|nv| nv.tag.to_lowercase() == "comment")
                    .and_then(|nv| nv.value.clone());
                crate::writer::gif_writer::write_gif(data, comment.as_deref())
            }
            FileType::Flac => {
                let changes: Vec<(&str, &str)> = self.new_values.iter()
                    .filter_map(|nv| Some((nv.tag.as_str(), nv.value.as_deref()?)))
                    .collect();
                crate::writer::flac_writer::write_flac(data, &changes)
            }
            FileType::Mp3 | FileType::Aiff => {
                let changes: Vec<(&str, &str)> = self.new_values.iter()
                    .filter_map(|nv| Some((nv.tag.as_str(), nv.value.as_deref()?)))
                    .collect();
                crate::writer::id3_writer::write_id3(data, &changes)
            }
            FileType::Jp2 | FileType::Jxl => {
                let new_xmp = if self.new_values.iter().any(|nv| nv.group.as_deref() == Some("XMP")) {
                    let refs: Vec<&NewValue> = self.new_values.iter()
                        .filter(|nv| nv.group.as_deref() == Some("XMP"))
                        .collect();
                    Some(self.build_new_xmp(&refs))
                } else { None };
                crate::writer::jp2_writer::write_jp2(data, new_xmp.as_deref(), None)
            }
            FileType::PostScript => {
                let changes: Vec<(&str, &str)> = self.new_values.iter()
                    .filter_map(|nv| Some((nv.tag.as_str(), nv.value.as_deref()?)))
                    .collect();
                crate::writer::ps_writer::write_postscript(data, &changes)
            }
            FileType::Ogg | FileType::Opus => {
                let changes: Vec<(&str, &str)> = self.new_values.iter()
                    .filter_map(|nv| Some((nv.tag.as_str(), nv.value.as_deref()?)))
                    .collect();
                crate::writer::ogg_writer::write_ogg(data, &changes)
            }
            FileType::Xmp => {
                let props: Vec<xmp_writer::XmpProperty> = self.new_values.iter()
                    .filter_map(|nv| {
                        let val = nv.value.as_deref()?;
                        Some(xmp_writer::XmpProperty {
                            namespace: nv.group.clone().unwrap_or_else(|| "dc".into()),
                            property: nv.tag.clone(),
                            values: vec![val.to_string()],
                            prop_type: xmp_writer::XmpPropertyType::Simple,
                        })
                    })
                    .collect();
                Ok(crate::writer::xmp_sidecar_writer::write_xmp_sidecar(&props))
            }
            _ => Err(Error::UnsupportedFileType(format!("writing not yet supported for {}", file_type))),
        }
    }

    /// Write metadata changes to JPEG data.
    fn write_jpeg(&self, data: &[u8]) -> Result<Vec<u8>> {
        // Classify new values by target group
        let mut exif_values: Vec<&NewValue> = Vec::new();
        let mut xmp_values: Vec<&NewValue> = Vec::new();
        let mut iptc_values: Vec<&NewValue> = Vec::new();
        let mut comment_value: Option<&str> = None;
        let mut remove_exif = false;
        let mut remove_xmp = false;
        let mut remove_iptc = false;
        let mut remove_comment = false;

        for nv in &self.new_values {
            let group = nv.group.as_deref().unwrap_or("");
            let group_upper = group.to_uppercase();

            // Check for group deletion
            if nv.value.is_none() && nv.tag == "*" {
                match group_upper.as_str() {
                    "EXIF" => { remove_exif = true; continue; }
                    "XMP" => { remove_xmp = true; continue; }
                    "IPTC" => { remove_iptc = true; continue; }
                    _ => {}
                }
            }

            match group_upper.as_str() {
                "XMP" => xmp_values.push(nv),
                "IPTC" => iptc_values.push(nv),
                "EXIF" | "IFD0" | "EXIFIFD" | "GPS" => exif_values.push(nv),
                "" => {
                    // Auto-detect best group based on tag name
                    if nv.tag.to_lowercase() == "comment" {
                        if nv.value.is_none() {
                            remove_comment = true;
                        } else {
                            comment_value = nv.value.as_deref();
                        }
                    } else if is_xmp_tag(&nv.tag) {
                        xmp_values.push(nv);
                    } else {
                        exif_values.push(nv);
                    }
                }
                _ => exif_values.push(nv), // default to EXIF
            }
        }

        // Build new EXIF data
        let new_exif = if !exif_values.is_empty() {
            Some(self.build_new_exif(data, &exif_values)?)
        } else {
            None
        };

        // Build new XMP data
        let new_xmp = if !xmp_values.is_empty() {
            Some(self.build_new_xmp(&xmp_values))
        } else {
            None
        };

        // Build new IPTC data
        let new_iptc_data = if !iptc_values.is_empty() {
            let records: Vec<iptc_writer::IptcRecord> = iptc_values
                .iter()
                .filter_map(|nv| {
                    let value = nv.value.as_deref()?;
                    let (record, dataset) = iptc_writer::tag_name_to_iptc(&nv.tag)?;
                    Some(iptc_writer::IptcRecord {
                        record,
                        dataset,
                        data: value.as_bytes().to_vec(),
                    })
                })
                .collect();
            if records.is_empty() {
                None
            } else {
                Some(iptc_writer::build_iptc(&records))
            }
        } else {
            None
        };

        // Rewrite JPEG
        jpeg_writer::write_jpeg(
            data,
            new_exif.as_deref(),
            new_xmp.as_deref(),
            new_iptc_data.as_deref(),
            comment_value,
            remove_exif,
            remove_xmp,
            remove_iptc,
            remove_comment,
        )
    }

    /// Build new EXIF data by merging existing EXIF with queued changes.
    fn build_new_exif(&self, jpeg_data: &[u8], values: &[&NewValue]) -> Result<Vec<u8>> {
        let bo = ByteOrderMark::BigEndian;
        let mut ifd0_entries = Vec::new();
        let mut exif_entries = Vec::new();
        let mut gps_entries = Vec::new();

        // Step 1: Extract existing EXIF entries from the JPEG
        let existing = extract_existing_exif_entries(jpeg_data, bo);
        for entry in &existing {
            match classify_exif_tag(entry.tag) {
                ExifIfdGroup::Ifd0 => ifd0_entries.push(entry.clone()),
                ExifIfdGroup::ExifIfd => exif_entries.push(entry.clone()),
                ExifIfdGroup::Gps => gps_entries.push(entry.clone()),
            }
        }

        // Step 2: Apply queued changes (add/replace/delete)
        let deleted_tags: Vec<u16> = values
            .iter()
            .filter(|nv| nv.value.is_none())
            .filter_map(|nv| tag_name_to_id(&nv.tag))
            .collect();

        // Remove deleted tags
        ifd0_entries.retain(|e| !deleted_tags.contains(&e.tag));
        exif_entries.retain(|e| !deleted_tags.contains(&e.tag));
        gps_entries.retain(|e| !deleted_tags.contains(&e.tag));

        // Add/replace new values
        for nv in values {
            if nv.value.is_none() {
                continue;
            }
            let value_str = nv.value.as_deref().unwrap_or("");
            let group = nv.group.as_deref().unwrap_or("");

            if let Some((tag_id, format, encoded)) = encode_exif_tag(&nv.tag, value_str, group, bo) {
                let entry = exif_writer::IfdEntry {
                    tag: tag_id,
                    format,
                    data: encoded,
                };

                let target = match group.to_uppercase().as_str() {
                    "GPS" => &mut gps_entries,
                    "EXIFIFD" => &mut exif_entries,
                    _ => match classify_exif_tag(tag_id) {
                        ExifIfdGroup::ExifIfd => &mut exif_entries,
                        ExifIfdGroup::Gps => &mut gps_entries,
                        ExifIfdGroup::Ifd0 => &mut ifd0_entries,
                    },
                };

                // Replace existing or add new
                if let Some(existing) = target.iter_mut().find(|e| e.tag == tag_id) {
                    *existing = entry;
                } else {
                    target.push(entry);
                }
            }
        }

        // Remove sub-IFD pointers from entries (they'll be rebuilt by build_exif)
        ifd0_entries.retain(|e| e.tag != 0x8769 && e.tag != 0x8825 && e.tag != 0xA005);

        exif_writer::build_exif(&ifd0_entries, &exif_entries, &gps_entries, bo)
    }

    /// Write metadata changes to PNG data.
    fn write_png(&self, data: &[u8]) -> Result<Vec<u8>> {
        let mut new_text: Vec<(&str, &str)> = Vec::new();
        let mut remove_text: Vec<&str> = Vec::new();

        // Collect text-based changes
        // We need to hold the strings in vectors that live long enough
        let owned_pairs: Vec<(String, String)> = self.new_values.iter()
            .filter(|nv| nv.value.is_some())
            .map(|nv| (nv.tag.clone(), nv.value.clone().unwrap()))
            .collect();

        for (tag, value) in &owned_pairs {
            new_text.push((tag.as_str(), value.as_str()));
        }

        for nv in &self.new_values {
            if nv.value.is_none() {
                remove_text.push(&nv.tag);
            }
        }

        png_writer::write_png(data, &new_text, None, &remove_text)
    }

    /// Write metadata changes to PSD data.
    fn write_psd(&self, data: &[u8]) -> Result<Vec<u8>> {
        let mut iptc_values = Vec::new();
        let mut xmp_values = Vec::new();

        for nv in &self.new_values {
            let group = nv.group.as_deref().unwrap_or("").to_uppercase();
            match group.as_str() {
                "XMP" => xmp_values.push(nv),
                "IPTC" => iptc_values.push(nv),
                _ => {
                    if is_xmp_tag(&nv.tag) { xmp_values.push(nv); }
                    else { iptc_values.push(nv); }
                }
            }
        }

        let new_iptc = if !iptc_values.is_empty() {
            let records: Vec<_> = iptc_values.iter().filter_map(|nv| {
                let value = nv.value.as_deref()?;
                let (record, dataset) = iptc_writer::tag_name_to_iptc(&nv.tag)?;
                Some(iptc_writer::IptcRecord { record, dataset, data: value.as_bytes().to_vec() })
            }).collect();
            if records.is_empty() { None } else { Some(iptc_writer::build_iptc(&records)) }
        } else { None };

        let new_xmp = if !xmp_values.is_empty() {
            let refs: Vec<&NewValue> = xmp_values.iter().copied().collect();
            Some(self.build_new_xmp(&refs))
        } else { None };

        psd_writer::write_psd(data, new_iptc.as_deref(), new_xmp.as_deref())
    }

    /// Write metadata changes to Matroska (MKV/WebM) data.
    fn write_matroska(&self, data: &[u8]) -> Result<Vec<u8>> {
        let changes: Vec<(&str, &str)> = self.new_values.iter()
            .filter_map(|nv| {
                let value = nv.value.as_deref()?;
                Some((nv.tag.as_str(), value))
            })
            .collect();

        matroska_writer::write_matroska(data, &changes)
    }

    /// Write metadata changes to PDF data.
    fn write_pdf(&self, data: &[u8]) -> Result<Vec<u8>> {
        let changes: Vec<(&str, &str)> = self.new_values.iter()
            .filter_map(|nv| {
                let value = nv.value.as_deref()?;
                Some((nv.tag.as_str(), value))
            })
            .collect();

        pdf_writer::write_pdf(data, &changes)
    }

    /// Write metadata changes to MP4/MOV data.
    fn write_mp4(&self, data: &[u8]) -> Result<Vec<u8>> {
        let mut ilst_tags: Vec<([u8; 4], String)> = Vec::new();
        let mut xmp_values: Vec<&NewValue> = Vec::new();

        for nv in &self.new_values {
            if nv.value.is_none() { continue; }
            let group = nv.group.as_deref().unwrap_or("").to_uppercase();
            if group == "XMP" {
                xmp_values.push(nv);
            } else if let Some(key) = mp4_writer::tag_to_ilst_key(&nv.tag) {
                ilst_tags.push((key, nv.value.clone().unwrap()));
            }
        }

        let tag_refs: Vec<(&[u8; 4], &str)> = ilst_tags.iter()
            .map(|(k, v)| (k, v.as_str()))
            .collect();

        let new_xmp = if !xmp_values.is_empty() {
            let refs: Vec<&NewValue> = xmp_values.iter().copied().collect();
            Some(self.build_new_xmp(&refs))
        } else {
            None
        };

        mp4_writer::write_mp4(data, &tag_refs, new_xmp.as_deref())
    }

    /// Write metadata changes to WebP data.
    fn write_webp(&self, data: &[u8]) -> Result<Vec<u8>> {
        let mut exif_values: Vec<&NewValue> = Vec::new();
        let mut xmp_values: Vec<&NewValue> = Vec::new();
        let mut remove_exif = false;
        let mut remove_xmp = false;

        for nv in &self.new_values {
            let group = nv.group.as_deref().unwrap_or("").to_uppercase();
            if nv.value.is_none() && nv.tag == "*" {
                if group == "EXIF" { remove_exif = true; }
                if group == "XMP" { remove_xmp = true; }
                continue;
            }
            match group.as_str() {
                "XMP" => xmp_values.push(nv),
                _ => exif_values.push(nv),
            }
        }

        let new_exif = if !exif_values.is_empty() {
            let bo = ByteOrderMark::BigEndian;
            let mut entries = Vec::new();
            for nv in &exif_values {
                if let Some(ref v) = nv.value {
                    let group = nv.group.as_deref().unwrap_or("");
                    if let Some((tag_id, format, encoded)) = encode_exif_tag(&nv.tag, v, group, bo) {
                        entries.push(exif_writer::IfdEntry { tag: tag_id, format, data: encoded });
                    }
                }
            }
            if !entries.is_empty() {
                Some(exif_writer::build_exif(&entries, &[], &[], bo)?)
            } else {
                None
            }
        } else {
            None
        };

        let new_xmp = if !xmp_values.is_empty() {
            Some(self.build_new_xmp(&xmp_values.iter().map(|v| *v).collect::<Vec<_>>()))
        } else {
            None
        };

        webp_writer::write_webp(
            data,
            new_exif.as_deref(),
            new_xmp.as_deref(),
            remove_exif,
            remove_xmp,
        )
    }

    /// Write metadata changes to TIFF data.
    fn write_tiff(&self, data: &[u8]) -> Result<Vec<u8>> {
        let bo = if data.starts_with(b"II") {
            ByteOrderMark::LittleEndian
        } else {
            ByteOrderMark::BigEndian
        };

        let mut changes: Vec<(u16, Vec<u8>)> = Vec::new();
        for nv in &self.new_values {
            if let Some(ref value) = nv.value {
                let group = nv.group.as_deref().unwrap_or("");
                if let Some((tag_id, _format, encoded)) = encode_exif_tag(&nv.tag, value, group, bo) {
                    changes.push((tag_id, encoded));
                }
            }
        }

        tiff_writer::write_tiff(data, &changes)
    }

    /// Build new XMP data from queued values.
    fn build_new_xmp(&self, values: &[&NewValue]) -> Vec<u8> {
        let mut properties = Vec::new();

        for nv in values {
            let value_str = match &nv.value {
                Some(v) => v.clone(),
                None => continue,
            };

            let ns = nv.group.as_deref().unwrap_or("dc").to_lowercase();
            let ns = if ns == "xmp" { "xmp".to_string() } else { ns };

            let prop_type = match nv.tag.to_lowercase().as_str() {
                "title" | "description" | "rights" => xmp_writer::XmpPropertyType::LangAlt,
                "subject" | "keywords" => xmp_writer::XmpPropertyType::Bag,
                "creator" => xmp_writer::XmpPropertyType::Seq,
                _ => xmp_writer::XmpPropertyType::Simple,
            };

            let values = if matches!(prop_type, xmp_writer::XmpPropertyType::Bag | xmp_writer::XmpPropertyType::Seq) {
                value_str.split(',').map(|s| s.trim().to_string()).collect()
            } else {
                vec![value_str]
            };

            properties.push(xmp_writer::XmpProperty {
                namespace: ns,
                property: nv.tag.clone(),
                values,
                prop_type,
            });
        }

        xmp_writer::build_xmp(&properties).into_bytes()
    }

    // ================================================================
    // Reading API
    // ================================================================

    /// Extract metadata from a file and return a simple name→value map.
    ///
    /// This is the high-level one-shot API, equivalent to ExifTool's `ImageInfo()`.
    pub fn image_info<P: AsRef<Path>>(&self, path: P) -> Result<ImageInfo> {
        let tags = self.extract_info(path)?;
        Ok(self.get_info(&tags))
    }

    /// Extract all metadata tags from a file.
    ///
    /// Returns the full `Tag` structs with groups, raw values, etc.
    pub fn extract_info<P: AsRef<Path>>(&self, path: P) -> Result<Vec<Tag>> {
        let path = path.as_ref();
        let data = fs::read(path).map_err(Error::Io)?;

        self.extract_info_from_bytes(&data, path)
    }

    /// Extract metadata from in-memory data.
    pub fn extract_info_from_bytes(&self, data: &[u8], path: &Path) -> Result<Vec<Tag>> {
        let file_type_result = self.detect_file_type(data, path);
        let (file_type, mut tags) = match file_type_result {
            Ok(ft) => {
                let t = self.process_file(data, ft).or_else(|_| {
                    self.process_by_extension(data, path)
                })?;
                (Some(ft), t)
            }
            Err(_) => {
                // File type unknown by magic/extension — try extension-based fallback
                let t = self.process_by_extension(data, path)?;
                (None, t)
            }
        };
        let file_type = file_type.unwrap_or(FileType::Zip); // placeholder for file-level tags

        // Add file-level tags
        tags.push(Tag {
            id: crate::tag::TagId::Text("FileType".into()),
            name: "FileType".into(),
            description: "File Type".into(),
            group: crate::tag::TagGroup {
                family0: "File".into(),
                family1: "File".into(),
                family2: "Other".into(),
            },
            raw_value: Value::String(format!("{:?}", file_type)),
            print_value: file_type.description().to_string(),
            priority: 0,
        });

        tags.push(Tag {
            id: crate::tag::TagId::Text("MIMEType".into()),
            name: "MIMEType".into(),
            description: "MIME Type".into(),
            group: crate::tag::TagGroup {
                family0: "File".into(),
                family1: "File".into(),
                family2: "Other".into(),
            },
            raw_value: Value::String(file_type.mime_type().to_string()),
            print_value: file_type.mime_type().to_string(),
            priority: 0,
        });

        if let Ok(metadata) = fs::metadata(path) {
            tags.push(Tag {
                id: crate::tag::TagId::Text("FileSize".into()),
                name: "FileSize".into(),
                description: "File Size".into(),
                group: crate::tag::TagGroup {
                    family0: "File".into(),
                    family1: "File".into(),
                    family2: "Other".into(),
                },
                raw_value: Value::U32(metadata.len() as u32),
                print_value: format_file_size(metadata.len()),
                priority: 0,
            });
        }

        // Add more file-level tags
        let file_tag = |name: &str, val: Value| -> Tag {
            Tag {
                id: crate::tag::TagId::Text(name.to_string()),
                name: name.to_string(), description: name.to_string(),
                group: crate::tag::TagGroup { family0: "File".into(), family1: "File".into(), family2: "Other".into() },
                raw_value: val.clone(), print_value: val.to_display_string(), priority: 0,
            }
        };

        if let Some(fname) = path.file_name().and_then(|n| n.to_str()) {
            tags.push(file_tag("FileName", Value::String(fname.to_string())));
        }
        if let Some(dir) = path.parent().and_then(|p| p.to_str()) {
            tags.push(file_tag("Directory", Value::String(dir.to_string())));
        }
        if let Some(ext) = path.extension().and_then(|e| e.to_str()) {
            tags.push(file_tag("FileTypeExtension", Value::String(ext.to_lowercase())));
        }

        #[cfg(unix)]
        if let Ok(metadata) = fs::metadata(path) {
            use std::os::unix::fs::MetadataExt;
            let mode = metadata.mode();
            tags.push(file_tag("FilePermissions", Value::String(format!("{:o}", mode & 0o7777))));

            // FileModifyDate
            if let Ok(modified) = metadata.modified() {
                if let Ok(dur) = modified.duration_since(std::time::UNIX_EPOCH) {
                    let secs = dur.as_secs() as i64;
                    tags.push(file_tag("FileModifyDate", Value::String(unix_to_datetime(secs))));
                }
            }
            // FileAccessDate
            if let Ok(accessed) = metadata.accessed() {
                if let Ok(dur) = accessed.duration_since(std::time::UNIX_EPOCH) {
                    let secs = dur.as_secs() as i64;
                    tags.push(file_tag("FileAccessDate", Value::String(unix_to_datetime(secs))));
                }
            }
            // FileInodeChangeDate (ctime on Unix)
            let ctime = metadata.ctime();
            if ctime > 0 {
                tags.push(file_tag("FileInodeChangeDate", Value::String(unix_to_datetime(ctime))));
            }
        }

        // ExifByteOrder (from TIFF header)
        if file_type == FileType::Jpeg || file_type == FileType::Tiff {
            let bo_str = if data.len() > 8 {
                // Check EXIF in JPEG or TIFF header
                let check = if data.starts_with(&[0xFF, 0xD8]) {
                    // JPEG: find APP1 EXIF header
                    data.windows(6).position(|w| w == b"Exif\0\0")
                        .map(|p| &data[p+6..])
                } else {
                    Some(&data[..])
                };
                if let Some(tiff) = check {
                    if tiff.starts_with(b"II") { "Little-endian (Intel, II)" }
                    else if tiff.starts_with(b"MM") { "Big-endian (Motorola, MM)" }
                    else { "" }
                } else { "" }
            } else { "" };
            if !bo_str.is_empty() {
                tags.push(file_tag("ExifByteOrder", Value::String(bo_str.to_string())));
            }
        }

        tags.push(file_tag("ExifToolVersion", Value::String(crate::VERSION.to_string())));

        // Compute composite tags
        let composite = crate::composite::compute_composite_tags(&tags);
        tags.extend(composite);

        // FLIR post-processing: remove LensID composite for FLIR cameras.
        // Perl's LensID composite requires LensType EXIF tag (not present in FLIR images),
        // and LensID-2 requires LensModel to match /(mm|\d\/F)/ (FLIR names like "FOL7"
        // don't match).  Our composite.rs uses a simpler fallback that picks up any non-empty
        // LensModel, so we remove LensID when the image is from a FLIR camera with FFF data.
        {
            let is_flir_fff = tags.iter().any(|t| t.group.family0 == "APP1"
                && t.group.family1 == "FLIR");
            if is_flir_fff {
                tags.retain(|t| !(t.name == "LensID" && t.group.family0 == "Composite"));
            }
        }

        // Olympus post-processing: remove the generic "Lens" composite for Olympus cameras.
        // In Perl, the "Lens" composite tag requires Canon:MinFocalLength (Canon namespace).
        // Our composite.rs generates Lens for any manufacturer that has MinFocalLength +
        // MaxFocalLength (e.g., Olympus Equipment sub-IFD).  Remove it for non-Canon cameras.
        {
            let make = tags.iter().find(|t| t.name == "Make")
                .map(|t| t.print_value.clone()).unwrap_or_default();
            if !make.to_uppercase().contains("CANON") {
                tags.retain(|t| t.name != "Lens" || t.group.family0 != "Composite");
            }
        }

        // Filter by requested tags if specified
        if !self.options.requested_tags.is_empty() {
            let requested: Vec<String> = self
                .options
                .requested_tags
                .iter()
                .map(|t| t.to_lowercase())
                .collect();
            tags.retain(|t| requested.contains(&t.name.to_lowercase()));
        }

        Ok(tags)
    }

    /// Format extracted tags into a simple name→value map.
    ///
    /// Handles duplicate tag names by appending group info.
    fn get_info(&self, tags: &[Tag]) -> ImageInfo {
        let mut info = ImageInfo::new();
        let mut seen: HashMap<String, usize> = HashMap::new();

        for tag in tags {
            let value = if self.options.print_conv {
                &tag.print_value
            } else {
                &tag.raw_value.to_display_string()
            };

            let count = seen.entry(tag.name.clone()).or_insert(0);
            *count += 1;

            if *count == 1 {
                info.insert(tag.name.clone(), value.clone());
            } else if self.options.duplicates {
                let key = format!("{} [{}:{}]", tag.name, tag.group.family0, tag.group.family1);
                info.insert(key, value.clone());
            }
        }

        info
    }

    /// Detect file type from magic bytes and extension.
    fn detect_file_type(&self, data: &[u8], path: &Path) -> Result<FileType> {
        // Try magic bytes first
        let header_len = data.len().min(256);
        if let Some(ft) = file_type::detect_from_magic(&data[..header_len]) {
            return Ok(ft);
        }

        // Fall back to extension
        if let Some(ext) = path.extension().and_then(|e| e.to_str()) {
            if let Some(ft) = file_type::detect_from_extension(ext) {
                return Ok(ft);
            }
        }

        let ext_str = path
            .extension()
            .and_then(|e| e.to_str())
            .unwrap_or("unknown");
        Err(Error::UnsupportedFileType(ext_str.to_string()))
    }

    /// Dispatch to the appropriate format reader.
    fn process_file(&self, data: &[u8], file_type: FileType) -> Result<Vec<Tag>> {
        match file_type {
            FileType::Jpeg => formats::jpeg::read_jpeg(data),
            FileType::Png | FileType::Mng => formats::png::read_png(data),
            // All TIFF-based formats (TIFF + most RAW formats)
            FileType::Tiff
            | FileType::Btf
            | FileType::Dng
            | FileType::Cr2
            | FileType::Nef
            | FileType::Arw
            | FileType::Sr2
            | FileType::Orf
            | FileType::Pef
            | FileType::Erf
            | FileType::Fff
            | FileType::Iiq
            | FileType::Rwl
            | FileType::Mef
            | FileType::Srw
            | FileType::Gpr
            | FileType::Arq
            | FileType::ThreeFR
            | FileType::Dcr
            | FileType::Rw2
            | FileType::Srf => formats::tiff::read_tiff(data),
            // Image formats
            FileType::Gif => formats::gif::read_gif(data),
            FileType::Bmp => formats::bmp::read_bmp(data),
            FileType::WebP | FileType::Avi | FileType::Wav => formats::riff::read_riff(data),
            FileType::Psd => formats::psd::read_psd(data),
            // Audio formats
            FileType::Mp3 => formats::id3::read_mp3(data),
            FileType::Flac => formats::flac::read_flac(data),
            FileType::Ogg | FileType::Opus => formats::ogg::read_ogg(data),
            FileType::Aiff => formats::aiff::read_aiff(data),
            // Video formats
            FileType::Mp4
            | FileType::QuickTime
            | FileType::M4a
            | FileType::ThreeGP
            | FileType::Heif
            | FileType::Avif
            | FileType::Cr3
            | FileType::F4v
            | FileType::Mqv
            | FileType::Lrv => formats::quicktime::read_quicktime(data),
            FileType::Mkv | FileType::WebM => formats::matroska::read_matroska(data),
            FileType::Asf | FileType::Wmv | FileType::Wma => formats::asf::read_asf(data),
            // RAW formats with custom containers
            FileType::Crw => formats::canon_raw::read_crw(data),
            FileType::Raf => formats::raf::read_raf(data),
            FileType::Mrw => formats::mrw::read_mrw(data),
            // Image formats
            FileType::Jp2 | FileType::J2c => formats::jp2::read_jp2(data),
            FileType::Jxl => formats::jp2::read_jxl(data),
            FileType::Ico => formats::ico::read_ico(data),
            FileType::Icc => formats::icc::read_icc(data),
            // Documents
            FileType::Pdf => formats::pdf::read_pdf(data),
            FileType::PostScript => formats::postscript::read_postscript(data),
            FileType::Zip | FileType::Docx | FileType::Xlsx | FileType::Pptx
            | FileType::Doc | FileType::Xls | FileType::Ppt => formats::zip::read_zip(data),
            FileType::Rtf => formats::rtf::read_rtf(data),
            // Metadata / Other
            FileType::Xmp => formats::xmp_file::read_xmp(data),
            FileType::Html => {
                // SVG files detected as HTML
                let is_svg = data.windows(4).take(512).any(|w| w == b"<svg");
                if is_svg {
                    formats::misc::read_svg(data)
                } else {
                    formats::html::read_html(data)
                }
            }
            FileType::Exe => formats::exe::read_exe(data),
            FileType::Font => formats::font::read_font(data),
            // Audio with ID3
            FileType::Aac | FileType::Ape | FileType::Mpc | FileType::Audible
            | FileType::WavPack | FileType::Dsf => formats::id3::read_mp3(data),
            FileType::RealAudio | FileType::RealMedia => {
                // Try ID3 first
                formats::id3::read_mp3(data).or_else(|_| Ok(Vec::new()))
            }
            // Misc formats
            FileType::Dicom => formats::misc::read_dicom(data),
            FileType::Fits => formats::misc::read_fits(data),
            FileType::Flv => formats::misc::read_flv(data),
            FileType::Swf => formats::misc::read_swf(data),
            FileType::Hdr => formats::misc::read_hdr(data),
            FileType::DjVu => formats::misc::read_djvu(data),
            FileType::Flif => formats::misc::read_flif(data),
            FileType::Bpg => formats::misc::read_bpg(data),
            FileType::Pcx => formats::misc::read_pcx(data),
            FileType::Pict => formats::misc::read_pict(data),
            FileType::M2ts => formats::misc::read_m2ts(data),
            FileType::Gzip => formats::misc::read_gzip(data),
            FileType::Rar => formats::misc::read_rar(data),
            _ => Err(Error::UnsupportedFileType(format!("{}", file_type))),
        }
    }

    /// Fallback: try to read file based on extension for formats without magic detection.
    fn process_by_extension(&self, data: &[u8], path: &Path) -> Result<Vec<Tag>> {
        let ext = path
            .extension()
            .and_then(|e| e.to_str())
            .unwrap_or("")
            .to_ascii_lowercase();

        match ext.as_str() {
            "ppm" | "pgm" | "pbm" => formats::misc::read_ppm(data),
            "pfm" => {
                // PFM can be Portable Float Map or Printer Font Metrics
                if data.len() >= 3 && data[0] == b'P' && (data[1] == b'f' || data[1] == b'F') {
                    formats::misc::read_ppm(data)
                } else {
                    Ok(Vec::new()) // Printer Font Metrics
                }
            }
            "json" => formats::misc::read_json(data),
            "svg" => formats::misc::read_svg(data),
            "txt" | "csv" | "log" | "igc" | "url" | "lnk" | "ram" => {
                Ok(Vec::new()) // Text-like: report file-level info only
            }
            "gpx" | "kml" | "xml" | "inx" => formats::xmp_file::read_xmp(data),
            "plist" | "aae" => {
                // Try XML plist or binary plist
                if data.starts_with(b"<?xml") || data.starts_with(b"bplist") {
                    formats::xmp_file::read_xmp(data).or_else(|_| Ok(Vec::new()))
                } else {
                    Ok(Vec::new())
                }
            }
            "vcf" | "ics" | "vcard" => Ok(Vec::new()), // vCard/iCal
            "xcf" => Ok(Vec::new()),      // GIMP
            "vrd" | "dr4" => Ok(Vec::new()), // Canon VRD
            "indd" | "indt" => Ok(Vec::new()), // InDesign
            "x3f" => Ok(Vec::new()),       // Sigma X3F
            "mie" => Ok(Vec::new()),       // MIE
            "exr" => Ok(Vec::new()),       // OpenEXR
            "dpx" | "dv" | "fpf" | "lfp" | "miff" | "moi" | "mrc"
            | "dss" | "mobi" | "pcapng" | "psp" | "pgf" | "raw"
            | "r3d" | "pmp" | "tnef" | "torrent" | "wpg" | "wtv"
            | "xisf" | "czi" | "iso" | "itc" | "macos" | "mxf"
            | "afm" | "pfb" | "ppt" | "dfont" => Ok(Vec::new()),
            _ => Err(Error::UnsupportedFileType(ext)),
        }
    }
}

impl Default for ExifTool {
    fn default() -> Self {
        Self::new()
    }
}

/// Detect the file type of a file at the given path.
pub fn get_file_type<P: AsRef<Path>>(path: P) -> Result<FileType> {
    let path = path.as_ref();
    let mut file = fs::File::open(path).map_err(Error::Io)?;
    let mut header = [0u8; 256];
    use std::io::Read;
    let n = file.read(&mut header).map_err(Error::Io)?;

    if let Some(ft) = file_type::detect_from_magic(&header[..n]) {
        return Ok(ft);
    }

    if let Some(ext) = path.extension().and_then(|e| e.to_str()) {
        if let Some(ft) = file_type::detect_from_extension(ext) {
            return Ok(ft);
        }
    }

    Err(Error::UnsupportedFileType("unknown".into()))
}

/// Classification of EXIF tags into IFD groups.
enum ExifIfdGroup {
    Ifd0,
    ExifIfd,
    Gps,
}

/// Determine which IFD a tag belongs to based on its ID.
fn classify_exif_tag(tag_id: u16) -> ExifIfdGroup {
    match tag_id {
        // ExifIFD tags
        0x829A..=0x829D | 0x8822..=0x8827 | 0x8830 | 0x9000..=0x9292
        | 0xA000..=0xA435 => ExifIfdGroup::ExifIfd,
        // GPS tags
        0x0000..=0x001F if tag_id <= 0x001F => ExifIfdGroup::Gps,
        // Everything else → IFD0
        _ => ExifIfdGroup::Ifd0,
    }
}

/// Extract existing EXIF entries from a JPEG file's APP1 segment.
fn extract_existing_exif_entries(jpeg_data: &[u8], target_bo: ByteOrderMark) -> Vec<exif_writer::IfdEntry> {
    let mut entries = Vec::new();

    // Find EXIF APP1 segment
    let mut pos = 2; // Skip SOI
    while pos + 4 <= jpeg_data.len() {
        if jpeg_data[pos] != 0xFF {
            pos += 1;
            continue;
        }
        let marker = jpeg_data[pos + 1];
        pos += 2;

        if marker == 0xDA || marker == 0xD9 {
            break; // SOS or EOI
        }
        if marker == 0xFF || marker == 0x00 || marker == 0xD8 || (0xD0..=0xD7).contains(&marker) {
            continue;
        }

        if pos + 2 > jpeg_data.len() {
            break;
        }
        let seg_len = u16::from_be_bytes([jpeg_data[pos], jpeg_data[pos + 1]]) as usize;
        if seg_len < 2 || pos + seg_len > jpeg_data.len() {
            break;
        }

        let seg_data = &jpeg_data[pos + 2..pos + seg_len];

        // EXIF APP1
        if marker == 0xE1 && seg_data.len() > 14 && seg_data.starts_with(b"Exif\0\0") {
            let tiff_data = &seg_data[6..];
            extract_ifd_entries(tiff_data, target_bo, &mut entries);
            break;
        }

        pos += seg_len;
    }

    entries
}

/// Extract IFD entries from TIFF data, re-encoding values in the target byte order.
fn extract_ifd_entries(
    tiff_data: &[u8],
    target_bo: ByteOrderMark,
    entries: &mut Vec<exif_writer::IfdEntry>,
) {
    use crate::metadata::exif::parse_tiff_header;

    let header = match parse_tiff_header(tiff_data) {
        Ok(h) => h,
        Err(_) => return,
    };

    let src_bo = header.byte_order;

    // Read IFD0
    read_ifd_for_merge(tiff_data, header.ifd0_offset as usize, src_bo, target_bo, entries);

    // Find ExifIFD and GPS pointers
    let ifd0_offset = header.ifd0_offset as usize;
    if ifd0_offset + 2 > tiff_data.len() {
        return;
    }
    let count = read_u16_bo(tiff_data, ifd0_offset, src_bo) as usize;
    for i in 0..count {
        let eoff = ifd0_offset + 2 + i * 12;
        if eoff + 12 > tiff_data.len() {
            break;
        }
        let tag = read_u16_bo(tiff_data, eoff, src_bo);
        let value_off = read_u32_bo(tiff_data, eoff + 8, src_bo) as usize;

        match tag {
            0x8769 => read_ifd_for_merge(tiff_data, value_off, src_bo, target_bo, entries),
            0x8825 => read_ifd_for_merge(tiff_data, value_off, src_bo, target_bo, entries),
            _ => {}
        }
    }
}

/// Read a single IFD and extract entries for merge.
fn read_ifd_for_merge(
    data: &[u8],
    offset: usize,
    src_bo: ByteOrderMark,
    target_bo: ByteOrderMark,
    entries: &mut Vec<exif_writer::IfdEntry>,
) {
    if offset + 2 > data.len() {
        return;
    }
    let count = read_u16_bo(data, offset, src_bo) as usize;

    for i in 0..count {
        let eoff = offset + 2 + i * 12;
        if eoff + 12 > data.len() {
            break;
        }

        let tag = read_u16_bo(data, eoff, src_bo);
        let dtype = read_u16_bo(data, eoff + 2, src_bo);
        let count_val = read_u32_bo(data, eoff + 4, src_bo);

        // Skip sub-IFD pointers and MakerNote
        if tag == 0x8769 || tag == 0x8825 || tag == 0xA005 || tag == 0x927C {
            continue;
        }

        let type_size = match dtype {
            1 | 2 | 6 | 7 => 1usize,
            3 | 8 => 2,
            4 | 9 | 11 | 13 => 4,
            5 | 10 | 12 => 8,
            _ => continue,
        };

        let total_size = type_size * count_val as usize;
        let raw_data = if total_size <= 4 {
            data[eoff + 8..eoff + 12].to_vec()
        } else {
            let voff = read_u32_bo(data, eoff + 8, src_bo) as usize;
            if voff + total_size > data.len() {
                continue;
            }
            data[voff..voff + total_size].to_vec()
        };

        // Re-encode multi-byte values if byte orders differ
        let final_data = if src_bo != target_bo && type_size > 1 {
            reencode_bytes(&raw_data, dtype, count_val as usize, src_bo, target_bo)
        } else {
            raw_data[..total_size].to_vec()
        };

        let format = match dtype {
            1 => exif_writer::ExifFormat::Byte,
            2 => exif_writer::ExifFormat::Ascii,
            3 => exif_writer::ExifFormat::Short,
            4 => exif_writer::ExifFormat::Long,
            5 => exif_writer::ExifFormat::Rational,
            6 => exif_writer::ExifFormat::SByte,
            7 => exif_writer::ExifFormat::Undefined,
            8 => exif_writer::ExifFormat::SShort,
            9 => exif_writer::ExifFormat::SLong,
            10 => exif_writer::ExifFormat::SRational,
            11 => exif_writer::ExifFormat::Float,
            12 => exif_writer::ExifFormat::Double,
            _ => continue,
        };

        entries.push(exif_writer::IfdEntry {
            tag,
            format,
            data: final_data,
        });
    }
}

/// Re-encode multi-byte values when converting between byte orders.
fn reencode_bytes(
    data: &[u8],
    dtype: u16,
    count: usize,
    src_bo: ByteOrderMark,
    dst_bo: ByteOrderMark,
) -> Vec<u8> {
    let mut out = Vec::with_capacity(data.len());
    match dtype {
        3 | 8 => {
            // 16-bit
            for i in 0..count {
                let v = read_u16_bo(data, i * 2, src_bo);
                match dst_bo {
                    ByteOrderMark::LittleEndian => out.extend_from_slice(&v.to_le_bytes()),
                    ByteOrderMark::BigEndian => out.extend_from_slice(&v.to_be_bytes()),
                }
            }
        }
        4 | 9 | 11 | 13 => {
            // 32-bit
            for i in 0..count {
                let v = read_u32_bo(data, i * 4, src_bo);
                match dst_bo {
                    ByteOrderMark::LittleEndian => out.extend_from_slice(&v.to_le_bytes()),
                    ByteOrderMark::BigEndian => out.extend_from_slice(&v.to_be_bytes()),
                }
            }
        }
        5 | 10 => {
            // Rational (two 32-bit)
            for i in 0..count {
                let n = read_u32_bo(data, i * 8, src_bo);
                let d = read_u32_bo(data, i * 8 + 4, src_bo);
                match dst_bo {
                    ByteOrderMark::LittleEndian => {
                        out.extend_from_slice(&n.to_le_bytes());
                        out.extend_from_slice(&d.to_le_bytes());
                    }
                    ByteOrderMark::BigEndian => {
                        out.extend_from_slice(&n.to_be_bytes());
                        out.extend_from_slice(&d.to_be_bytes());
                    }
                }
            }
        }
        12 => {
            // 64-bit double
            for i in 0..count {
                let mut bytes = [0u8; 8];
                bytes.copy_from_slice(&data[i * 8..i * 8 + 8]);
                if src_bo != dst_bo {
                    bytes.reverse();
                }
                out.extend_from_slice(&bytes);
            }
        }
        _ => out.extend_from_slice(data),
    }
    out
}

fn read_u16_bo(data: &[u8], offset: usize, bo: ByteOrderMark) -> u16 {
    if offset + 2 > data.len() { return 0; }
    match bo {
        ByteOrderMark::LittleEndian => u16::from_le_bytes([data[offset], data[offset + 1]]),
        ByteOrderMark::BigEndian => u16::from_be_bytes([data[offset], data[offset + 1]]),
    }
}

fn read_u32_bo(data: &[u8], offset: usize, bo: ByteOrderMark) -> u32 {
    if offset + 4 > data.len() { return 0; }
    match bo {
        ByteOrderMark::LittleEndian => u32::from_le_bytes([data[offset], data[offset + 1], data[offset + 2], data[offset + 3]]),
        ByteOrderMark::BigEndian => u32::from_be_bytes([data[offset], data[offset + 1], data[offset + 2], data[offset + 3]]),
    }
}

/// Map tag name to numeric EXIF tag ID.
fn tag_name_to_id(name: &str) -> Option<u16> {
    encode_exif_tag(name, "", "", ByteOrderMark::BigEndian).map(|(id, _, _)| id)
}

/// Convert a tag value to a safe filename.
fn value_to_filename(value: &str) -> String {
    value
        .chars()
        .map(|c| match c {
            '/' | '\\' | ':' | '*' | '?' | '"' | '<' | '>' | '|' => '_',
            c if c.is_control() => '_',
            c => c,
        })
        .collect::<String>()
        .trim()
        .to_string()
}

/// Parse a date shift string like "+1:0:0" (add 1 hour) or "-0:30:0" (subtract 30 min).
/// Returns (sign, hours, minutes, seconds).
pub fn parse_date_shift(shift: &str) -> Option<(i32, u32, u32, u32)> {
    let (sign, rest) = if shift.starts_with('-') {
        (-1, &shift[1..])
    } else if shift.starts_with('+') {
        (1, &shift[1..])
    } else {
        (1, shift)
    };

    let parts: Vec<&str> = rest.split(':').collect();
    match parts.len() {
        1 => {
            let h: u32 = parts[0].parse().ok()?;
            Some((sign, h, 0, 0))
        }
        2 => {
            let h: u32 = parts[0].parse().ok()?;
            let m: u32 = parts[1].parse().ok()?;
            Some((sign, h, m, 0))
        }
        3 => {
            let h: u32 = parts[0].parse().ok()?;
            let m: u32 = parts[1].parse().ok()?;
            let s: u32 = parts[2].parse().ok()?;
            Some((sign, h, m, s))
        }
        _ => None,
    }
}

/// Shift a datetime string by the given amount.
/// Input format: "YYYY:MM:DD HH:MM:SS"
pub fn shift_datetime(datetime: &str, shift: &str) -> Option<String> {
    let (sign, hours, minutes, seconds) = parse_date_shift(shift)?;

    // Parse date/time
    if datetime.len() < 19 {
        return None;
    }
    let year: i32 = datetime[0..4].parse().ok()?;
    let month: u32 = datetime[5..7].parse().ok()?;
    let day: u32 = datetime[8..10].parse().ok()?;
    let hour: u32 = datetime[11..13].parse().ok()?;
    let min: u32 = datetime[14..16].parse().ok()?;
    let sec: u32 = datetime[17..19].parse().ok()?;

    // Convert to total seconds, shift, convert back
    let total_secs = (hour * 3600 + min * 60 + sec) as i64
        + sign as i64 * (hours * 3600 + minutes * 60 + seconds) as i64;

    let days_shift = if total_secs < 0 {
        -1 - (-total_secs - 1) as i64 / 86400
    } else {
        total_secs / 86400
    };

    let time_secs = ((total_secs % 86400) + 86400) % 86400;
    let new_hour = (time_secs / 3600) as u32;
    let new_min = ((time_secs % 3600) / 60) as u32;
    let new_sec = (time_secs % 60) as u32;

    // Simple day shifting (doesn't handle month/year rollover perfectly for large shifts)
    let mut new_day = day as i32 + days_shift as i32;
    let mut new_month = month;
    let mut new_year = year;

    let days_in_month = |m: u32, y: i32| -> i32 {
        match m {
            1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
            4 | 6 | 9 | 11 => 30,
            2 => if (y % 4 == 0 && y % 100 != 0) || y % 400 == 0 { 29 } else { 28 },
            _ => 30,
        }
    };

    while new_day > days_in_month(new_month, new_year) {
        new_day -= days_in_month(new_month, new_year);
        new_month += 1;
        if new_month > 12 {
            new_month = 1;
            new_year += 1;
        }
    }
    while new_day < 1 {
        new_month = if new_month == 1 { 12 } else { new_month - 1 };
        if new_month == 12 {
            new_year -= 1;
        }
        new_day += days_in_month(new_month, new_year);
    }

    Some(format!(
        "{:04}:{:02}:{:02} {:02}:{:02}:{:02}",
        new_year, new_month, new_day, new_hour, new_min, new_sec
    ))
}

fn unix_to_datetime(secs: i64) -> String {
    let days = secs / 86400;
    let time = secs % 86400;
    let h = time / 3600;
    let m = (time % 3600) / 60;
    let s = time % 60;
    let mut y = 1970i32;
    let mut rem = days;
    loop {
        let dy = if (y % 4 == 0 && y % 100 != 0) || y % 400 == 0 { 366 } else { 365 };
        if rem < dy { break; }
        rem -= dy;
        y += 1;
    }
    let leap = (y % 4 == 0 && y % 100 != 0) || y % 400 == 0;
    let months = [31, if leap { 29 } else { 28 }, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
    let mut mo = 1;
    for &dm in &months {
        if rem < dm { break; }
        rem -= dm;
        mo += 1;
    }
    format!("{:04}:{:02}:{:02} {:02}:{:02}:{:02}", y, mo, rem + 1, h, m, s)
}

fn format_file_size(bytes: u64) -> String {
    if bytes < 1024 {
        format!("{} bytes", bytes)
    } else if bytes < 1024 * 1024 {
        format!("{:.1} kB", bytes as f64 / 1024.0)
    } else if bytes < 1024 * 1024 * 1024 {
        format!("{:.1} MB", bytes as f64 / (1024.0 * 1024.0))
    } else {
        format!("{:.1} GB", bytes as f64 / (1024.0 * 1024.0 * 1024.0))
    }
}

/// Check if a tag name is typically XMP.
fn is_xmp_tag(tag: &str) -> bool {
    matches!(
        tag.to_lowercase().as_str(),
        "title" | "description" | "subject" | "creator" | "rights"
        | "keywords" | "rating" | "label" | "hierarchicalsubject"
    )
}

/// Encode an EXIF tag value to binary.
/// Returns (tag_id, format, encoded_data) or None if tag is unknown.
fn encode_exif_tag(
    tag_name: &str,
    value: &str,
    _group: &str,
    bo: ByteOrderMark,
) -> Option<(u16, exif_writer::ExifFormat, Vec<u8>)> {
    let tag_lower = tag_name.to_lowercase();

    // Map common tag names to EXIF tag IDs and formats
    let (tag_id, format): (u16, exif_writer::ExifFormat) = match tag_lower.as_str() {
        // IFD0 string tags
        "imagedescription" => (0x010E, exif_writer::ExifFormat::Ascii),
        "make" => (0x010F, exif_writer::ExifFormat::Ascii),
        "model" => (0x0110, exif_writer::ExifFormat::Ascii),
        "software" => (0x0131, exif_writer::ExifFormat::Ascii),
        "modifydate" | "datetime" => (0x0132, exif_writer::ExifFormat::Ascii),
        "artist" => (0x013B, exif_writer::ExifFormat::Ascii),
        "copyright" => (0x8298, exif_writer::ExifFormat::Ascii),
        // IFD0 numeric tags
        "orientation" => (0x0112, exif_writer::ExifFormat::Short),
        "xresolution" => (0x011A, exif_writer::ExifFormat::Rational),
        "yresolution" => (0x011B, exif_writer::ExifFormat::Rational),
        "resolutionunit" => (0x0128, exif_writer::ExifFormat::Short),
        // ExifIFD tags
        "datetimeoriginal" => (0x9003, exif_writer::ExifFormat::Ascii),
        "createdate" | "datetimedigitized" => (0x9004, exif_writer::ExifFormat::Ascii),
        "usercomment" => (0x9286, exif_writer::ExifFormat::Undefined),
        "imageuniqueid" => (0xA420, exif_writer::ExifFormat::Ascii),
        "ownername" | "cameraownername" => (0xA430, exif_writer::ExifFormat::Ascii),
        "serialnumber" | "bodyserialnumber" => (0xA431, exif_writer::ExifFormat::Ascii),
        "lensmake" => (0xA433, exif_writer::ExifFormat::Ascii),
        "lensmodel" => (0xA434, exif_writer::ExifFormat::Ascii),
        "lensserialnumber" => (0xA435, exif_writer::ExifFormat::Ascii),
        _ => return None,
    };

    let encoded = match format {
        exif_writer::ExifFormat::Ascii => exif_writer::encode_ascii(value),
        exif_writer::ExifFormat::Short => {
            let v: u16 = value.parse().ok()?;
            exif_writer::encode_u16(v, bo)
        }
        exif_writer::ExifFormat::Long => {
            let v: u32 = value.parse().ok()?;
            exif_writer::encode_u32(v, bo)
        }
        exif_writer::ExifFormat::Rational => {
            // Parse "N/D" or just "N"
            if let Some(slash) = value.find('/') {
                let num: u32 = value[..slash].trim().parse().ok()?;
                let den: u32 = value[slash + 1..].trim().parse().ok()?;
                exif_writer::encode_urational(num, den, bo)
            } else if let Ok(v) = value.parse::<f64>() {
                // Convert float to rational
                let den = 10000u32;
                let num = (v * den as f64).round() as u32;
                exif_writer::encode_urational(num, den, bo)
            } else {
                return None;
            }
        }
        exif_writer::ExifFormat::Undefined => {
            // UserComment: 8 bytes charset + data
            let mut data = vec![0x41, 0x53, 0x43, 0x49, 0x49, 0x00, 0x00, 0x00]; // "ASCII\0\0\0"
            data.extend_from_slice(value.as_bytes());
            data
        }
        _ => return None,
    };

    Some((tag_id, format, encoded))
}