//! Pdf - Main facade for PDF document creation
//!
//! This is the main entry point for creating PDF documents.
//! Provides a high-level API similar to fpdf2's FPDF class.
//!
//! Based on: fpdf2/fpdf/fpdf.py (FPDF class)

const std = @import("std");
const Page = @import("page.zig").Page;
const ContentStream = @import("content_stream.zig").ContentStream;
const Color = @import("graphics/color.zig").Color;
const Font = @import("fonts/type1.zig").Font;
const TrueTypeFont = @import("fonts/ttf.zig").TrueTypeFont;
const PageSize = @import("objects/base.zig").PageSize;
const Orientation = @import("objects/base.zig").Orientation;
const Unit = @import("objects/base.zig").Unit;
const OutputProducer = @import("output/producer.zig").OutputProducer;
const PageData = @import("output/producer.zig").PageData;
const ExtGStateData = @import("output/producer.zig").ExtGStateData;
const GradientOutputData = @import("output/producer.zig").GradientOutputData;
const producer_GradientType = @import("output/producer.zig").GradientType;
const GradientData = @import("graphics/gradient.zig").GradientData;
const page_GradientType = @import("graphics/gradient.zig").GradientType;
const DocumentMetadata = @import("output/producer.zig").DocumentMetadata;
const CompressionOptions = @import("output/producer.zig").CompressionOptions;
const ImageInfo = @import("images/image_info.zig").ImageInfo;
const jpeg = @import("images/jpeg.zig");
const png = @import("images/png.zig");
const images_mod = @import("images/mod.zig");
const Outline = @import("outline.zig").Outline;

/// Configuration constants for zcatpdf
pub const Config = struct {
    /// Maximum file size for image loading (default: 10MB)
    pub const max_image_file_size: usize = 10 * 1024 * 1024;
    /// Maximum decompression buffer size (default: 100MB)
    pub const max_decompression_size: usize = 100 * 1024 * 1024;
};

/// A PDF document builder.
///
/// Example usage:
/// ```zig
/// var pdf = Pdf.init(allocator, .{});
/// defer pdf.deinit();
///
/// var page = try pdf.addPage(.{});
/// try page.setFont(.helvetica_bold, 24);
/// try page.drawText(50, 750, "Hello, World!");
///
/// try pdf.save("hello.pdf");
/// ```
pub const Pdf = struct {
    allocator: std.mem.Allocator,

    /// All pages in the document
    pages: std.ArrayListUnmanaged(Page),

    /// All images in the document
    images: std.ArrayListUnmanaged(ImageInfo),

    /// TrueType fonts loaded
    ttf_fonts: std.ArrayListUnmanaged(TrueTypeFont),

    /// TTF font data (raw bytes, need to keep alive)
    ttf_data: std.ArrayListUnmanaged([]u8),

    /// Document outline (bookmarks)
    outline: Outline,

    /// Document metadata
    title: ?[]const u8 = null,
    author: ?[]const u8 = null,
    subject: ?[]const u8 = null,
    creator: ?[]const u8 = null,

    /// Default page settings
    default_page_size: PageSize,
    default_orientation: Orientation,
    unit: Unit,

    /// Compression settings
    compression: CompressionOptions,

    const Self = @This();

    /// Options for creating a PDF document.
    pub const Options = struct {
        /// Default page size
        page_size: PageSize = .a4,
        /// Default page orientation
        orientation: Orientation = .portrait,
        /// Unit of measurement for user coordinates
        unit: Unit = .pt,
        /// Compression options for PDF streams
        compression: CompressionOptions = .{},
    };

    /// Options for adding a page.
    pub const PageOptions = struct {
        /// Page size (uses document default if null)
        size: ?PageSize = null,
        /// Page orientation (uses document default if null)
        orientation: ?Orientation = null,
    };

    // =========================================================================
    // Initialization
    // =========================================================================

    /// Creates a new PDF document.
    pub fn init(allocator: std.mem.Allocator, options: Options) Self {
        return .{
            .allocator = allocator,
            .pages = .{},
            .images = .{},
            .ttf_fonts = .{},
            .ttf_data = .{},
            .outline = Outline.init(allocator),
            .default_page_size = options.page_size,
            .default_orientation = options.orientation,
            .unit = options.unit,
            .compression = options.compression,
        };
    }

    /// Sets the compression level (0-12, where 0=disabled, 6=default, 12=max).
    pub fn setCompressionLevel(self: *Self, level: i32) void {
        if (level <= 0) {
            self.compression.enabled = false;
        } else {
            self.compression.enabled = true;
            self.compression.level = @min(level, 12);
        }
    }

    /// Enables or disables stream compression.
    pub fn setCompression(self: *Self, enabled: bool) void {
        self.compression.enabled = enabled;
    }

    /// Frees all resources.
    pub fn deinit(self: *Self) void {
        for (self.pages.items) |*page| {
            page.deinit();
        }
        self.pages.deinit(self.allocator);

        // Free image data if owned
        for (self.images.items) |*img| {
            img.deinit(self.allocator);
        }
        self.images.deinit(self.allocator);

        // Free TTF fonts
        for (self.ttf_fonts.items) |*font| {
            font.deinit();
        }
        self.ttf_fonts.deinit(self.allocator);

        // Free TTF raw data
        for (self.ttf_data.items) |data| {
            self.allocator.free(data);
        }
        self.ttf_data.deinit(self.allocator);

        self.outline.deinit();
    }

    // =========================================================================
    // Document Metadata
    // =========================================================================

    /// Sets the document title.
    pub fn setTitle(self: *Self, title: []const u8) void {
        self.title = title;
    }

    /// Sets the document author.
    pub fn setAuthor(self: *Self, author: []const u8) void {
        self.author = author;
    }

    /// Sets the document subject.
    pub fn setSubject(self: *Self, subject: []const u8) void {
        self.subject = subject;
    }

    /// Sets the document creator.
    pub fn setCreator(self: *Self, creator: []const u8) void {
        self.creator = creator;
    }

    // =========================================================================
    // Page Management
    // =========================================================================

    /// Adds a new page to the document.
    pub fn addPage(self: *Self, options: PageOptions) !*Page {
        const size = options.size orelse self.default_page_size;
        const orientation = options.orientation orelse self.default_orientation;

        const dims = size.dimensions();
        const width = if (orientation == .landscape) dims.height else dims.width;
        const height = if (orientation == .landscape) dims.width else dims.height;

        const page = Page.initCustom(self.allocator, width, height);
        try self.pages.append(self.allocator, page);
        return &self.pages.items[self.pages.items.len - 1];
    }

    /// Adds a new page with custom dimensions (in the document's unit).
    pub fn addPageCustom(self: *Self, width: f32, height: f32) !*Page {
        const width_pt = self.unit.toPoints(width);
        const height_pt = self.unit.toPoints(height);

        const page = Page.initCustom(self.allocator, width_pt, height_pt);
        try self.pages.append(self.allocator, page);
        return &self.pages.items[self.pages.items.len - 1];
    }

    /// Returns the number of pages.
    pub fn pageCount(self: *const Self) usize {
        return self.pages.items.len;
    }

    /// Returns a page by index (0-based).
    pub fn getPage(self: *Self, index: usize) ?*Page {
        if (index < self.pages.items.len) {
            return &self.pages.items[index];
        }
        return null;
    }

    // =========================================================================
    // Image Management
    // =========================================================================

    /// Adds a JPEG image from raw data and returns its index.
    /// The image data is stored and will be embedded in the PDF.
    pub fn addJpegImage(self: *Self, jpeg_data: []const u8) !usize {
        const info = try jpeg.parse(jpeg_data);
        try self.images.append(self.allocator, info);
        return self.images.items.len - 1;
    }

    /// Adds a JPEG image from a file and returns its index.
    pub fn addJpegImageFromFile(self: *Self, path: []const u8) !usize {
        const file = try std.fs.cwd().openFile(path, .{});
        defer file.close();

        const data = try file.readToEndAlloc(self.allocator, Config.max_image_file_size);

        var info = try jpeg.parse(data);
        // Mark as owned since we allocated the data
        info.data = data;
        info.owns_data = true;

        try self.images.append(self.allocator, info);
        return self.images.items.len - 1;
    }

    /// Adds a PNG image from raw data and returns its index.
    /// Supports PNG with alpha channel (transparency).
    pub fn addPngImage(self: *Self, png_data: []const u8) !usize {
        const info = try png.parse(self.allocator, png_data);
        try self.images.append(self.allocator, info);
        return self.images.items.len - 1;
    }

    /// Adds a PNG image from a file and returns its index.
    /// Supports PNG with alpha channel (transparency).
    pub fn addPngImageFromFile(self: *Self, path: []const u8) !usize {
        const file = try std.fs.cwd().openFile(path, .{});
        defer file.close();

        const data = try file.readToEndAlloc(self.allocator, Config.max_image_file_size);
        defer self.allocator.free(data);

        const info = try png.parse(self.allocator, data);
        try self.images.append(self.allocator, info);
        return self.images.items.len - 1;
    }

    /// Adds an image from file, auto-detecting format (JPEG or PNG).
    pub fn addImageFromFile(self: *Self, path: []const u8) !usize {
        const file = try std.fs.cwd().openFile(path, .{});
        defer file.close();

        const data = try file.readToEndAlloc(self.allocator, Config.max_image_file_size);

        const format = images_mod.detectFormat(data) orelse {
            self.allocator.free(data);
            return error.UnsupportedImageFormat;
        };

        switch (format) {
            .jpeg => {
                var info = try jpeg.parse(data);
                info.data = data;
                info.owns_data = true;
                try self.images.append(self.allocator, info);
            },
            .png => {
                defer self.allocator.free(data);
                const info = try png.parse(self.allocator, data);
                try self.images.append(self.allocator, info);
            },
        }

        return self.images.items.len - 1;
    }

    /// Returns the ImageInfo for an image by index.
    pub fn getImage(self: *const Self, index: usize) ?*const ImageInfo {
        if (index < self.images.items.len) {
            return &self.images.items[index];
        }
        return null;
    }

    /// Returns the number of images.
    pub fn imageCount(self: *const Self) usize {
        return self.images.items.len;
    }

    // =========================================================================
    // TrueType Font Management
    // =========================================================================

    /// Adds a TrueType font from raw data and returns its index.
    /// The font can then be used with page.setTtfFont(index, size).
    pub fn addTtfFont(self: *Self, ttf_data: []const u8) !usize {
        const font = try TrueTypeFont.parse(self.allocator, ttf_data);
        try self.ttf_fonts.append(self.allocator, font);
        return self.ttf_fonts.items.len - 1;
    }

    /// Adds a TrueType font from a file and returns its index.
    pub fn addTtfFontFromFile(self: *Self, path: []const u8) !usize {
        const file = try std.fs.cwd().openFile(path, .{});
        defer file.close();

        const data = try file.readToEndAlloc(self.allocator, Config.max_image_file_size);
        try self.ttf_data.append(self.allocator, data);

        const font = try TrueTypeFont.parse(self.allocator, data);
        try self.ttf_fonts.append(self.allocator, font);
        return self.ttf_fonts.items.len - 1;
    }

    /// Returns the TrueTypeFont for a font by index.
    pub fn getTtfFont(self: *const Self, index: usize) ?*const TrueTypeFont {
        if (index < self.ttf_fonts.items.len) {
            return &self.ttf_fonts.items[index];
        }
        return null;
    }

    /// Returns the number of TTF fonts loaded.
    pub fn ttfFontCount(self: *const Self) usize {
        return self.ttf_fonts.items.len;
    }

    // =========================================================================
    // Bookmarks / Outline
    // =========================================================================

    /// Adds a top-level bookmark pointing to a page.
    pub fn addBookmark(self: *Self, title: []const u8, page: usize) !void {
        try self.outline.addBookmark(title, page);
    }

    /// Adds a bookmark with a specific Y position on the page.
    pub fn addBookmarkAt(self: *Self, title: []const u8, page: usize, y: f32) !void {
        try self.outline.addBookmarkAt(title, page, y);
    }

    /// Adds a nested bookmark (child).
    pub fn addBookmarkChild(self: *Self, title: []const u8, page: usize, level: u8) !void {
        try self.outline.addChild(title, page, level);
    }

    /// Adds a nested bookmark with Y position.
    pub fn addBookmarkChildAt(self: *Self, title: []const u8, page: usize, y: f32, level: u8) !void {
        try self.outline.addChildAt(title, page, y, level);
    }

    /// Returns the number of bookmarks.
    pub fn bookmarkCount(self: *const Self) usize {
        return self.outline.count();
    }

    // =========================================================================
    // Output
    // =========================================================================

    /// Renders the document to a byte buffer.
    pub fn render(self: *Self) ![]u8 {
        // Collect page data
        var page_data: std.ArrayListUnmanaged(PageData) = .{};
        defer page_data.deinit(self.allocator);

        // Keep track of all slices to free them after generation
        var font_slices: std.ArrayListUnmanaged([]Font) = .{};
        var extgstate_slices: std.ArrayListUnmanaged([]ExtGStateData) = .{};
        var gradient_slices: std.ArrayListUnmanaged([]GradientOutputData) = .{};
        defer {
            for (font_slices.items) |slice| {
                self.allocator.free(slice);
            }
            font_slices.deinit(self.allocator);
            for (extgstate_slices.items) |slice| {
                self.allocator.free(slice);
            }
            extgstate_slices.deinit(self.allocator);
            for (gradient_slices.items) |slice| {
                self.allocator.free(slice);
            }
            gradient_slices.deinit(self.allocator);
        }

        for (self.pages.items) |*page| {
            // Get fonts used - convert to owned slice
            var fonts: std.ArrayListUnmanaged(Font) = .{};
            var iter = page.fonts_used.keyIterator();
            while (iter.next()) |font| {
                try fonts.append(self.allocator, font.*);
            }
            const fonts_slice = try fonts.toOwnedSlice(self.allocator);
            try font_slices.append(self.allocator, fonts_slice);

            // Get ExtGStates used - convert to owned slice
            var extgstates: std.ArrayListUnmanaged(ExtGStateData) = .{};
            for (page.getExtGStates()) |gs| {
                try extgstates.append(self.allocator, .{
                    .fill_opacity = gs.fill_opacity,
                    .stroke_opacity = gs.stroke_opacity,
                });
            }
            const extgstates_slice = try extgstates.toOwnedSlice(self.allocator);
            try extgstate_slices.append(self.allocator, extgstates_slice);

            // Get Gradients used - convert to output format
            var gradients: std.ArrayListUnmanaged(GradientOutputData) = .{};
            for (page.getGradients()) |grad| {
                // Convert GradientData to GradientOutputData
                const start_color = grad.start_color.toRgbFloats();
                const end_color = grad.end_color.toRgbFloats();

                try gradients.append(self.allocator, .{
                    .gradient_type = if (grad.gradient_type == page_GradientType.linear)
                        producer_GradientType.linear
                    else
                        producer_GradientType.radial,
                    .coords = grad.coords,
                    .start_color = .{ start_color.r, start_color.g, start_color.b },
                    .end_color = .{ end_color.r, end_color.g, end_color.b },
                });
            }
            const gradients_slice = try gradients.toOwnedSlice(self.allocator);
            try gradient_slices.append(self.allocator, gradients_slice);

            try page_data.append(self.allocator, .{
                .width = page.width,
                .height = page.height,
                .content = page.getContent(),
                .fonts_used = fonts_slice,
                .links = page.getLinks(),
                .extgstates = extgstates_slice,
                .gradients = gradients_slice,
            });
        }

        // Collect image pointers
        var image_ptrs: std.ArrayListUnmanaged(*const ImageInfo) = .{};
        defer image_ptrs.deinit(self.allocator);

        for (self.images.items) |*img| {
            try image_ptrs.append(self.allocator, img);
        }

        // Generate PDF
        var producer = OutputProducer.initWithCompression(self.allocator, self.compression);
        defer producer.deinit();

        return try producer.generateFull(page_data.items, .{
            .title = self.title,
            .author = self.author,
            .subject = self.subject,
            .creator = self.creator,
        }, image_ptrs.items, self.outline.getItems());
    }

    /// Saves the document to a file.
    pub fn save(self: *Self, path: []const u8) !void {
        const data = try self.render();
        defer self.allocator.free(data);

        const file = try std.fs.cwd().createFile(path, .{});
        defer file.close();

        try file.writeAll(data);
    }

    /// Outputs the document and returns the bytes.
    pub fn output(self: *Self) ![]u8 {
        return try self.render();
    }
};

// =============================================================================
// Tests
// =============================================================================

test "Pdf init" {
    const allocator = std.testing.allocator;

    var pdf = Pdf.init(allocator, .{});
    defer pdf.deinit();

    try std.testing.expectEqual(@as(usize, 0), pdf.pageCount());
}

test "Pdf addPage" {
    const allocator = std.testing.allocator;

    var pdf = Pdf.init(allocator, .{});
    defer pdf.deinit();

    _ = try pdf.addPage(.{});
    try std.testing.expectEqual(@as(usize, 1), pdf.pageCount());

    _ = try pdf.addPage(.{ .size = .letter });
    try std.testing.expectEqual(@as(usize, 2), pdf.pageCount());
}

test "Pdf metadata" {
    const allocator = std.testing.allocator;

    var pdf = Pdf.init(allocator, .{});
    defer pdf.deinit();

    pdf.setTitle("Test Document");
    pdf.setAuthor("Test Author");

    try std.testing.expectEqualStrings("Test Document", pdf.title.?);
    try std.testing.expectEqualStrings("Test Author", pdf.author.?);
}

test "Pdf render" {
    const allocator = std.testing.allocator;

    var pdf = Pdf.init(allocator, .{});
    defer pdf.deinit();

    var page = try pdf.addPage(.{});
    try page.setFont(.helvetica, 12);
    try page.drawText(100, 700, "Hello");

    const output = try pdf.render();
    defer allocator.free(output);

    try std.testing.expect(std.mem.startsWith(u8, output, "%PDF-1.4"));
    try std.testing.expect(std.mem.endsWith(u8, output, "%%EOF\n"));
}