//! Image module for zcatpdf
//!
//! Provides image parsing and embedding support for PDF generation.
//! Supports JPEG (direct embedding) and PNG (with alpha support).

pub const jpeg = @import("jpeg.zig");
pub const png = @import("png.zig");
pub const ImageInfo = @import("image_info.zig").ImageInfo;
pub const ImageFormat = @import("image_info.zig").ImageFormat;

// Re-export common functions
pub const parseJpeg = jpeg.parse;
pub const parsePng = png.parse;

/// Detects image format from raw bytes
pub fn detectFormat(data: []const u8) ?ImageFormat {
    if (data.len < 8) return null;

    // JPEG: starts with FF D8 FF
    if (data[0] == 0xFF and data[1] == 0xD8 and data[2] == 0xFF) {
        return .jpeg;
    }

    // PNG: starts with 89 50 4E 47 0D 0A 1A 0A
    if (data[0] == 0x89 and data[1] == 0x50 and data[2] == 0x4E and data[3] == 0x47 and
        data[4] == 0x0D and data[5] == 0x0A and data[6] == 0x1A and data[7] == 0x0A)
    {
        return .png;
    }

    return null;
}

test "detect JPEG format" {
    const jpeg_header = [_]u8{ 0xFF, 0xD8, 0xFF, 0xE0, 0x00, 0x10, 0x4A, 0x46 };
    const format = detectFormat(&jpeg_header);
    try @import("std").testing.expectEqual(ImageFormat.jpeg, format.?);
}

test "detect PNG format" {
    const png_header = [_]u8{ 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
    const format = detectFormat(&png_header);
    try @import("std").testing.expectEqual(ImageFormat.png, format.?);
}

test "detect unknown format" {
    const unknown = [_]u8{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 };
    const format = detectFormat(&unknown);
    try @import("std").testing.expect(format == null);
}