// FFI functions are called from generated UniFFI bindings (C-ABI),
// so Rust's dead_code analysis doesn't see the calls.
#![allow(dead_code)]

uniffi::setup_scaffolding!();

pub use zx_document_core::material_type::{MaterialType, PreviewMode};
pub use zx_document_core::image_meta::ImageMeta;
pub use zx_document_core::text::TextStats;
pub use zx_document_core::search::SearchResult;
pub use zx_document_core::anchors::NoteAnchor;
pub use zx_document_core::progress::ReadingPosition;
pub use zx_document_core::events::ReadingEvent;

use zx_document_core::blocks as core_blocks;

// FFI-compatible DocumentBlock (tuple variants, UniFFI proc-macro)
#[derive(Debug, uniffi::Enum)]
pub enum DocumentBlock {
    Heading(String, u8, String),
    Paragraph(String, String),
    List(String, bool, Vec<String>),
    CodeBlock(String, Option<String>, String),
    Quote(String, String),
    Table(String, Vec<String>, Vec<Vec<String>>),
    ImageBlock(String, String, Option<String>),
    HorizontalRule(String),
}

impl From<core_blocks::DocumentBlock> for DocumentBlock {
    fn from(b: core_blocks::DocumentBlock) -> Self {
        match b {
            core_blocks::DocumentBlock::Heading { id, level, text } => {
                DocumentBlock::Heading(id, level, text)
            }
            core_blocks::DocumentBlock::Paragraph { id, text } => {
                DocumentBlock::Paragraph(id, text)
            }
            core_blocks::DocumentBlock::List { id, ordered, items } => {
                DocumentBlock::List(id, ordered, items)
            }
            core_blocks::DocumentBlock::CodeBlock { id, language, code } => {
                DocumentBlock::CodeBlock(id, language, code)
            }
            core_blocks::DocumentBlock::Quote { id, text } => {
                DocumentBlock::Quote(id, text)
            }
            core_blocks::DocumentBlock::Table { id, headers, rows } => {
                DocumentBlock::Table(id, headers, rows)
            }
            core_blocks::DocumentBlock::Image { id, src, alt } => {
                DocumentBlock::ImageBlock(id, src, alt)
            }
            core_blocks::DocumentBlock::HorizontalRule { id } => {
                DocumentBlock::HorizontalRule(id)
            }
        }
    }
}

#[derive(Debug, uniffi::Error)]
pub enum DocumentError {
    FileNotFound,
    UnsupportedFormat,
    ParseError,
    InvalidEncoding,
    IoError,
}

impl std::fmt::Display for DocumentError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::FileNotFound => write!(f, "File not found"),
            Self::UnsupportedFormat => write!(f, "Unsupported format"),
            Self::ParseError => write!(f, "Parse error"),
            Self::InvalidEncoding => write!(f, "Invalid encoding"),
            Self::IoError => write!(f, "IO error"),
        }
    }
}

impl std::error::Error for DocumentError {}

impl From<zx_document_core::error::DocumentError> for DocumentError {
    fn from(e: zx_document_core::error::DocumentError) -> Self {
        match e {
            zx_document_core::error::DocumentError::FileNotFound(_) => Self::FileNotFound,
            zx_document_core::error::DocumentError::UnsupportedFormat(_) => Self::UnsupportedFormat,
            zx_document_core::error::DocumentError::ParseError(_) => Self::ParseError,
            zx_document_core::error::DocumentError::InvalidEncoding => Self::InvalidEncoding,
            zx_document_core::error::DocumentError::IoError(_) => Self::IoError,
        }
    }
}

#[uniffi::export]
fn detect_material_type(file_path: String) -> Result<MaterialType, DocumentError> {
    zx_document_core::material_type::detect_material_type(&file_path).map_err(Into::into)
}

#[uniffi::export]
fn read_image_meta(file_path: String) -> Result<ImageMeta, DocumentError> {
    zx_document_core::image_meta::read_image_meta(&file_path).map_err(Into::into)
}

#[uniffi::export]
fn read_text_stats(file_path: String) -> Result<TextStats, DocumentError> {
    let content = std::fs::read_to_string(&file_path).map_err(|_| DocumentError::FileNotFound)?;
    Ok(zx_document_core::text::text_stats(&content))
}

#[uniffi::export]
fn parse_text(content: String) -> Result<Vec<DocumentBlock>, DocumentError> {
    let blocks = zx_document_core::text::parse_text_content(&content);
    let result: Vec<DocumentBlock> = blocks.into_iter().map(Into::into).collect();
    Ok(result)
}

#[uniffi::export]
fn parse_markdown(content: String) -> Result<Vec<DocumentBlock>, DocumentError> {
    let blocks = zx_document_core::markdown::parse_markdown(&content).map_err(|e| match e {
        zx_document_core::error::DocumentError::ParseError(_) => DocumentError::ParseError,
        _ => DocumentError::ParseError,
    })?;
    let result: Vec<DocumentBlock> = blocks.into_iter().map(Into::into).collect();
    Ok(result)
}

/// Out-pointer free: avoids struct-passing ABI issues
#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_rustbuffer_free_separate(
    capacity: u64,
    len: u64,
    data: *mut u8,
) {
    if data.is_null() { return; }
    unsafe {
        let _v = Vec::from_raw_parts(data, len as usize, capacity as usize);
        // _v drops here, freeing the memory
    }
}

/// Workaround: receive raw bytes via separate len/data args, return via out-pointers
/// Avoids all struct-passing ABI issues on ARM64 iOS.
#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_rustbuffer_from_bytes_separate(
    len: i32,
    data: *const u8,
    out_capacity: *mut u64,
    out_len: *mut u64,
    out_data: *mut *mut u8,
) {
    let mut call_status = uniffi::RustCallStatus::default();
    let buf = unsafe {
        uniffi::ffi::uniffi_rustbuffer_from_bytes(
            uniffi::ForeignBytes::from_raw_parts(data, len),
            &mut call_status,
        )
    };
    unsafe {
        *out_capacity = buf.capacity() as u64;
        *out_len = buf.len() as u64;
        *out_data = buf.data_pointer() as *mut u8;
    }
    // Transfer ownership to caller — don't drop the buffer
    std::mem::forget(buf);
}

/// Full parse_markdown via raw bytes, result via out-pointers — avoids all struct-passing ABI issues
#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_parse_markdown_separate(
    len: i32,
    data: *const u8,
    out_capacity: *mut u64,
    out_len: *mut u64,
    out_data: *mut *mut u8,
    out_error_code: *mut i8,
) {
    let slice = unsafe { std::slice::from_raw_parts(data, len as usize) };
    let content = match std::str::from_utf8(slice) {
        Ok(s) => s.to_string(),
        Err(_) => {
            unsafe { *out_error_code = -1; }
            return;
        }
    };

    let result = crate::parse_markdown(content);

    // Serialize result using UniFFI
    use uniffi::LowerReturn;
    let lowered = <Result<Vec<DocumentBlock>, DocumentError> as LowerReturn<UniFfiTag>>::lower_return(result);
    match lowered {
        Ok(buf) => {
            unsafe {
                *out_capacity = buf.capacity() as u64;
                *out_len = buf.len() as u64;
                *out_data = buf.data_pointer() as *mut u8;
                *out_error_code = 0;
            }
            std::mem::forget(buf);
        }
        Err(e) => {
            unsafe { *out_error_code = -1; }
        }
    }
}

#[uniffi::export]
fn search_markdown_blocks(blocks: Vec<DocumentBlock>, query: String) -> Vec<SearchResult> {
    let core_blocks: Vec<core_blocks::DocumentBlock> = blocks.into_iter().map(core_block_from_ffi).collect();
    zx_document_core::search::search_blocks(&core_blocks, &query)
}

#[uniffi::export]
fn search_text_content(content: String, query: String) -> Vec<SearchResult> {
    zx_document_core::search::search_text(&content, &query)
}

#[uniffi::export]
fn create_note_anchor(material_id: String, position: Option<ReadingPosition>) -> NoteAnchor {
    zx_document_core::anchors::NoteAnchor::from_position(&material_id, position.as_ref())
}

#[uniffi::export]
fn push_reading_event(event: ReadingEvent) {
    zx_document_core::events::push_reading_event(event)
}

#[uniffi::export]
fn update_reading_position(material_id: String, position: ReadingPosition) {
    zx_document_core::events::update_reading_position(&material_id, position)
}

#[uniffi::export]
fn export_pending_events() -> Vec<ReadingEvent> {
    zx_document_core::events::export_pending_events()
}

#[uniffi::export]
fn clear_exported_events(count: u32) {
    zx_document_core::events::clear_exported_events(count as usize)
}

/// Helper: serialize a Result<T, DocumentError> into out-pointers.
/// Generic over T; the RustBuffer methods are accessed via the concrete type
/// after the `lower_return` call.
macro_rules! write_result_to_out {
    ($result:expr, $out_capacity:ident, $out_len:ident, $out_data:ident, $out_error_code:ident) => {{
        use uniffi::LowerReturn;
        match <Result<_, DocumentError> as LowerReturn<UniFfiTag>>::lower_return($result) {
            Ok(buf) => {
                unsafe {
                    *$out_capacity = buf.capacity() as u64;
                    *$out_len = buf.len() as u64;
                    *$out_data = buf.data_pointer() as *mut u8;
                    *$out_error_code = 0;
                }
                std::mem::forget(buf);
            }
            Err(_) => {
                unsafe { *$out_error_code = -1; }
            }
        }
    }};
}

/// Helper: read a UTF-8 string from raw bytes, or set error and return false.
unsafe fn read_str_input(len: i32, data: *const u8, out_error_code: *mut i8) -> Option<String> {
    let slice = std::slice::from_raw_parts(data, len as usize);
    match std::str::from_utf8(slice) {
        Ok(s) => Some(s.to_string()),
        Err(_) => { *out_error_code = -1; None },
    }
}

// ─── Batch 1 out-pointer functions: String input → Result<T, E> output ───

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_detect_material_type_separate(
    len: i32, data: *const u8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let file_path = match unsafe { read_str_input(len, data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let result = crate::detect_material_type(file_path);
    write_result_to_out!(result, out_capacity, out_len, out_data, out_error_code);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_read_image_meta_separate(
    len: i32, data: *const u8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let file_path = match unsafe { read_str_input(len, data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let result = crate::read_image_meta(file_path);
    write_result_to_out!(result, out_capacity, out_len, out_data, out_error_code);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_read_text_stats_separate(
    len: i32, data: *const u8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let file_path = match unsafe { read_str_input(len, data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let result = crate::read_text_stats(file_path);
    write_result_to_out!(result, out_capacity, out_len, out_data, out_error_code);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_parse_text_separate(
    len: i32, data: *const u8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let content = match unsafe { read_str_input(len, data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let result = crate::parse_text(content);
    write_result_to_out!(result, out_capacity, out_len, out_data, out_error_code);
}

// ─── Helper: lift from raw buffer fields ───

macro_rules! lift_from_raw {
    ($T:ty, $capacity:expr, $len:expr, $data:expr) => {{
        let v = unsafe { Vec::from_raw_parts($data as *mut u8, $len as usize, $capacity as usize) };
        let buf = uniffi::RustBuffer::from_vec(v);
        <$T as uniffi::Lift<UniFfiTag>>::try_lift(buf).expect(concat!("failed to lift ", stringify!($T)))
    }};
}

// ─── Batch 2: complex type input/output ───

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_push_reading_event_separate(
    event_cap: u64, event_len: u64, event_data: *const u8,
) {
    let event: ReadingEvent = lift_from_raw!(ReadingEvent, event_cap, event_len, event_data);
    crate::push_reading_event(event);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_update_reading_position_separate(
    mid_len: i32, mid_data: *const u8,
    pos_cap: u64, pos_len: u64, pos_data: *const u8,
    out_error_code: *mut i8,
) {
    let material_id = match unsafe { read_str_input(mid_len, mid_data, out_error_code) } {
        Some(s) => s, None => return,
    };
    unsafe { *out_error_code = 0; }
    let position: ReadingPosition = lift_from_raw!(ReadingPosition, pos_cap, pos_len, pos_data);
    crate::update_reading_position(material_id, position);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_export_pending_events_separate(
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let result: Vec<ReadingEvent> = crate::export_pending_events();
    write_result_to_out!(Ok::<_, DocumentError>(result), out_capacity, out_len, out_data, out_error_code);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_create_note_anchor_separate(
    mid_len: i32, mid_data: *const u8,
    pos_cap: u64, pos_len: u64, pos_data: *const u8, pos_has_value: i8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let material_id = match unsafe { read_str_input(mid_len, mid_data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let position: Option<ReadingPosition> = if pos_has_value != 0 {
        Some(lift_from_raw!(ReadingPosition, pos_cap, pos_len, pos_data))
    } else {
        None
    };
    let result: Result<NoteAnchor, DocumentError> = Ok(crate::create_note_anchor(material_id, position));
    write_result_to_out!(result, out_capacity, out_len, out_data, out_error_code);
}

// ─── Batch 3: search functions ───

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_search_markdown_blocks_separate(
    blocks_cap: u64, blocks_len: u64, blocks_data: *const u8,
    query_len: i32, query_data: *const u8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let query = match unsafe { read_str_input(query_len, query_data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let blocks: Vec<DocumentBlock> = lift_from_raw!(Vec<DocumentBlock>, blocks_cap, blocks_len, blocks_data);
    let result: Vec<SearchResult> = crate::search_markdown_blocks(blocks, query);
    write_result_to_out!(Ok::<_, DocumentError>(result), out_capacity, out_len, out_data, out_error_code);
}

#[no_mangle]
pub extern "C" fn ffi_zx_document_ffi_search_text_content_separate(
    content_len: i32, content_data: *const u8,
    query_len: i32, query_data: *const u8,
    out_capacity: *mut u64, out_len: *mut u64, out_data: *mut *mut u8, out_error_code: *mut i8,
) {
    let content = match unsafe { read_str_input(content_len, content_data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let query = match unsafe { read_str_input(query_len, query_data, out_error_code) } {
        Some(s) => s, None => return,
    };
    let result: Vec<SearchResult> = crate::search_text_content(content, query);
    write_result_to_out!(Ok::<_, DocumentError>(result), out_capacity, out_len, out_data, out_error_code);
}

// Reverse conversion: FFI DocumentBlock → core DocumentBlock, used by search.
fn core_block_from_ffi(block: DocumentBlock) -> core_blocks::DocumentBlock {
    match block {
        DocumentBlock::Heading(id, level, text) => {
            core_blocks::DocumentBlock::Heading { id, level, text }
        }
        DocumentBlock::Paragraph(id, text) => {
            core_blocks::DocumentBlock::Paragraph { id, text }
        }
        DocumentBlock::List(id, ordered, items) => {
            core_blocks::DocumentBlock::List { id, ordered, items }
        }
        DocumentBlock::CodeBlock(id, language, code) => {
            core_blocks::DocumentBlock::CodeBlock { id, language, code }
        }
        DocumentBlock::Quote(id, text) => {
            core_blocks::DocumentBlock::Quote { id, text }
        }
        DocumentBlock::Table(id, headers, rows) => {
            core_blocks::DocumentBlock::Table { id, headers, rows }
        }
        DocumentBlock::ImageBlock(id, src, alt) => {
            core_blocks::DocumentBlock::Image { id, src, alt }
        }
        DocumentBlock::HorizontalRule(id) => {
            core_blocks::DocumentBlock::HorizontalRule { id }
        }
    }
}