// SPDX-License-Identifier: GPL-3.0-or-later
// src/document/loader.rs
//
// Document loading: format dispatch and directory scanning.

use crate::document::format::{detect_format, DocumentFormat};
use crate::document::portable::PortableModel;
use crate::document::raster::RasterModel;
use crate::document::session::{SessionData, SessionItem};
use crate::document::vector::VectorModel;
use crate::document::{core::PageLayout, DocumentContent};
use crate::error::{Error, Result};
use std::path::Path;

/// Loads a document from a path and returns its content.
pub fn load_document(path: &Path) -> Result<DocumentContent> {
    if !path.exists() {
        return Err(Error::NotFound(format!("{:?}", path)));
    }

    match detect_format(path) {
        Some(DocumentFormat::Portable) => {
            // TODO: Replace with actual pdfium-render loading.
            Ok(DocumentContent::Portable(PortableModel {
                path: path.to_path_buf(),
                page_count: 3,
                layout: PageLayout::new(vec![(595.0, 842.0); 3], 10.0),
            }))
        }
        Some(DocumentFormat::Vector) => {
            // TODO: Replace with actual usvg parsing.
            Ok(DocumentContent::Vector(VectorModel {
                path: path.to_path_buf(),
                view_box: None,
            }))
        }
        Some(DocumentFormat::Raster) => {
            // TODO: Replace with actual image-crate loading.
            Ok(DocumentContent::Raster(RasterModel {
                path: path.to_path_buf(),
                dimensions: (1920, 1080),
            }))
        }
        None => Err(Error::Unsupported(format!(
            "extension: {}",
            path.extension()
                .and_then(|e| e.to_str())
                .unwrap_or("(none)")
        ))),
    }
}

/// Scans a directory for supported files and populates the session.
pub fn scan_directory_into(session: &mut SessionData, dir: &Path) {
    if let Ok(entries) = std::fs::read_dir(dir) {
        let mut paths: Vec<_> = entries
            .filter_map(|e| e.ok())
            .map(|e| e.path())
            .filter(|p| p.is_file() && detect_format(p).is_some())
            .collect();

        paths.sort();

        session.items = paths.into_iter().map(|p| SessionItem::new(p, 0)).collect();
    }

    session.current_index = if session.items.is_empty() {
        None
    } else {
        Some(0)
    };
}