// Copyright (C) 2004-2021 Artifex Software, Inc.
//
// This file is part of MuPDF.
//
// MuPDF is free software: you can redistribute it and/or modify it under the
// terms of the GNU Affero General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
// details.
//
// You should have received a copy of the GNU Affero General Public License
// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
//
// Alternative licensing terms are available from the licensor.
// For commercial licensing, see <https://www.artifex.com/> or contact
// Artifex Software, Inc., 1305 Grant Avenue - Suite 200, Novato,
// CA 94945, U.S.A., +1(415)492-9861, for further information.

#include "mupdf/fitz.h"
#include "pdf-annot-imp.h"

#include <stdlib.h>
#include <string.h>
#include <limits.h>

int
pdf_count_pages(fz_context *ctx, pdf_document *doc)
{
	/* FIXME: We should reset linear_page_count to 0 when editing starts
	 * (or when linear loading ends) */
	if (doc->linear_page_count != 0)
		return doc->linear_page_count;
	return pdf_to_int(ctx, pdf_dict_getp(ctx, pdf_trailer(ctx, doc), "Root/Pages/Count"));
}

int pdf_count_pages_imp(fz_context *ctx, fz_document *doc, int chapter)
{
	return pdf_count_pages(ctx, (pdf_document*)doc);
}

static int
pdf_load_page_tree_imp(fz_context *ctx, pdf_document *doc, pdf_obj *node, int idx)
{
	pdf_obj *type = pdf_dict_get(ctx, node, PDF_NAME(Type));
	if (pdf_name_eq(ctx, type, PDF_NAME(Pages)))
	{
		pdf_obj *kids = pdf_dict_get(ctx, node, PDF_NAME(Kids));
		int i, n = pdf_array_len(ctx, kids);

		if (pdf_mark_obj(ctx, node))
			fz_throw(ctx, FZ_ERROR_GENERIC, "cycle in page tree");
		fz_try(ctx)
			for (i = 0; i < n; ++i)
				idx = pdf_load_page_tree_imp(ctx, doc, pdf_array_get(ctx, kids, i), idx);
		fz_always(ctx)
			pdf_unmark_obj(ctx, node);
		fz_catch(ctx)
			fz_rethrow(ctx);
	}
	else if (pdf_name_eq(ctx, type, PDF_NAME(Page)))
	{
		if (idx >= doc->rev_page_count)
			fz_throw(ctx, FZ_ERROR_GENERIC, "too many kids in page tree");
		doc->rev_page_map[idx].page = idx;
		doc->rev_page_map[idx].object = pdf_to_num(ctx, node);
		++idx;
	}
	else
	{
		fz_throw(ctx, FZ_ERROR_GENERIC, "non-page object in page tree");
	}
	return idx;
}

static int
cmp_rev_page_map(const void *va, const void *vb)
{
	const pdf_rev_page_map *a = va;
	const pdf_rev_page_map *b = vb;
	return a->object - b->object;
}

void
pdf_load_page_tree(fz_context *ctx, pdf_document *doc)
{
	if (!doc->rev_page_map)
	{
		doc->rev_page_count = pdf_count_pages(ctx, doc);
		doc->rev_page_map = Memento_label(fz_malloc_array(ctx, doc->rev_page_count, pdf_rev_page_map), "pdf_rev_page_map");
		pdf_load_page_tree_imp(ctx, doc, pdf_dict_getp(ctx, pdf_trailer(ctx, doc), "Root/Pages"), 0);
		qsort(doc->rev_page_map, doc->rev_page_count, sizeof *doc->rev_page_map, cmp_rev_page_map);
	}
}

void
pdf_drop_page_tree(fz_context *ctx, pdf_document *doc)
{
	fz_free(ctx, doc->rev_page_map);
	doc->rev_page_map = NULL;
	doc->rev_page_count = 0;
}

enum
{
	LOCAL_STACK_SIZE = 16
};

static pdf_obj *
pdf_lookup_page_loc_imp(fz_context *ctx, pdf_document *doc, pdf_obj *node, int *skip, pdf_obj **parentp, int *indexp)
{
	pdf_obj *kids;
	pdf_obj *hit = NULL;
	int i, len;
	pdf_obj *local_stack[LOCAL_STACK_SIZE];
	pdf_obj **stack = &local_stack[0];
	int stack_max = LOCAL_STACK_SIZE;
	int stack_len = 0;

	fz_var(hit);
	fz_var(stack);
	fz_var(stack_len);
	fz_var(stack_max);

	fz_try(ctx)
	{
		do
		{
			kids = pdf_dict_get(ctx, node, PDF_NAME(Kids));
			len = pdf_array_len(ctx, kids);

			if (len == 0)
				fz_throw(ctx, FZ_ERROR_GENERIC, "malformed page tree");

			/* Every node we need to unmark goes into the stack */
			if (stack_len == stack_max)
			{
				if (stack == &local_stack[0])
				{
					stack = fz_malloc_array(ctx, stack_max * 2, pdf_obj*);
					memcpy(stack, &local_stack[0], stack_max * sizeof(*stack));
				}
				else
				{
					stack = fz_realloc_array(ctx, stack, stack_max * 2, pdf_obj*);
				}
				stack_max *= 2;
			}
			stack[stack_len++] = node;

			if (pdf_mark_obj(ctx, node))
				fz_throw(ctx, FZ_ERROR_GENERIC, "cycle in page tree");

			for (i = 0; i < len; i++)
			{
				pdf_obj *kid = pdf_array_get(ctx, kids, i);
				pdf_obj *type = pdf_dict_get(ctx, kid, PDF_NAME(Type));
				if (type ? pdf_name_eq(ctx, type, PDF_NAME(Pages)) : pdf_dict_get(ctx, kid, PDF_NAME(Kids)) && !pdf_dict_get(ctx, kid, PDF_NAME(MediaBox)))
				{
					int count = pdf_dict_get_int(ctx, kid, PDF_NAME(Count));
					if (*skip < count)
					{
						node = kid;
						break;
					}
					else
					{
						*skip -= count;
					}
				}
				else
				{
					if (type ? !pdf_name_eq(ctx, type, PDF_NAME(Page)) : !pdf_dict_get(ctx, kid, PDF_NAME(MediaBox)))
						fz_warn(ctx, "non-page object in page tree (%s)", pdf_to_name(ctx, type));
					if (*skip == 0)
					{
						if (parentp) *parentp = node;
						if (indexp) *indexp = i;
						hit = kid;
						break;
					}
					else
					{
						(*skip)--;
					}
				}
			}
		}
		/* If i < len && hit != NULL the desired page was found in the
		Kids array, done. If i < len && hit == NULL the found page tree
		node contains a Kids array that contains the desired page, loop
		back to top to extract it. When i == len the Kids array has been
		exhausted without finding the desired page, give up.
		*/
		while (hit == NULL && i < len);
	}
	fz_always(ctx)
	{
		for (i = stack_len; i > 0; i--)
			pdf_unmark_obj(ctx, stack[i-1]);
		if (stack != &local_stack[0])
			fz_free(ctx, stack);
	}
	fz_catch(ctx)
	{
		fz_rethrow(ctx);
	}

	return hit;
}

pdf_obj *
pdf_lookup_page_loc(fz_context *ctx, pdf_document *doc, int needle, pdf_obj **parentp, int *indexp)
{
	pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
	pdf_obj *node = pdf_dict_get(ctx, root, PDF_NAME(Pages));
	int skip = needle;
	pdf_obj *hit;

	if (!node)
		fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find page tree");

	hit = pdf_lookup_page_loc_imp(ctx, doc, node, &skip, parentp, indexp);
	if (!hit)
		fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find page %d in page tree", needle+1);
	return hit;
}

pdf_obj *
pdf_lookup_page_obj(fz_context *ctx, pdf_document *doc, int needle)
{
	return pdf_lookup_page_loc(ctx, doc, needle, NULL, NULL);
}

static int
pdf_count_pages_before_kid(fz_context *ctx, pdf_document *doc, pdf_obj *parent, int kid_num)
{
	pdf_obj *kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
	int i, total = 0, len = pdf_array_len(ctx, kids);
	for (i = 0; i < len; i++)
	{
		pdf_obj *kid = pdf_array_get(ctx, kids, i);
		if (pdf_to_num(ctx, kid) == kid_num)
			return total;
		if (pdf_name_eq(ctx, pdf_dict_get(ctx, kid, PDF_NAME(Type)), PDF_NAME(Pages)))
		{
			pdf_obj *count = pdf_dict_get(ctx, kid, PDF_NAME(Count));
			int n = pdf_to_int(ctx, count);
			if (!pdf_is_int(ctx, count) || n < 0)
				fz_throw(ctx, FZ_ERROR_GENERIC, "illegal or missing count in pages tree");
			total += n;
		}
		else
			total++;
	}
	fz_throw(ctx, FZ_ERROR_GENERIC, "kid not found in parent's kids array");
}

static int
pdf_lookup_page_number_slow(fz_context *ctx, pdf_document *doc, pdf_obj *node)
{
	int needle = pdf_to_num(ctx, node);
	int total = 0;
	pdf_obj *parent, *parent2;

	if (!pdf_name_eq(ctx, pdf_dict_get(ctx, node, PDF_NAME(Type)), PDF_NAME(Page)))
		fz_throw(ctx, FZ_ERROR_GENERIC, "invalid page object");

	parent2 = parent = pdf_dict_get(ctx, node, PDF_NAME(Parent));
	fz_var(parent);
	fz_try(ctx)
	{
		while (pdf_is_dict(ctx, parent))
		{
			if (pdf_mark_obj(ctx, parent))
				fz_throw(ctx, FZ_ERROR_GENERIC, "cycle in page tree (parents)");
			total += pdf_count_pages_before_kid(ctx, doc, parent, needle);
			needle = pdf_to_num(ctx, parent);
			parent = pdf_dict_get(ctx, parent, PDF_NAME(Parent));
		}
	}
	fz_always(ctx)
	{
		/* Run back and unmark */
		while (parent2)
		{
			pdf_unmark_obj(ctx, parent2);
			if (parent2 == parent)
				break;
			parent2 = pdf_dict_get(ctx, parent2, PDF_NAME(Parent));
		}
	}
	fz_catch(ctx)
	{
		fz_rethrow(ctx);
	}

	return total;
}

static int
pdf_lookup_page_number_fast(fz_context *ctx, pdf_document *doc, int needle)
{
	int l = 0;
	int r = doc->rev_page_count - 1;
	while (l <= r)
	{
		int m = (l + r) >> 1;
		int c = needle - doc->rev_page_map[m].object;
		if (c < 0)
			r = m - 1;
		else if (c > 0)
			l = m + 1;
		else
			return doc->rev_page_map[m].page;
	}
	return -1;
}

int
pdf_lookup_page_number(fz_context *ctx, pdf_document *doc, pdf_obj *page)
{
	if (doc->rev_page_map)
		return pdf_lookup_page_number_fast(ctx, doc, pdf_to_num(ctx, page));
	else
		return pdf_lookup_page_number_slow(ctx, doc, page);
}

int
pdf_lookup_anchor(fz_context *ctx, pdf_document *doc, const char *name, float *xp, float *yp)
{
	pdf_obj *needle, *dest = NULL;
	char *uri;

	if (xp) *xp = 0;
	if (yp) *yp = 0;

	needle = pdf_new_string(ctx, name, strlen(name));
	fz_try(ctx)
		dest = pdf_lookup_dest(ctx, doc, needle);
	fz_always(ctx)
		pdf_drop_obj(ctx, needle);
	fz_catch(ctx)
		fz_rethrow(ctx);

	if (dest)
	{
		uri = pdf_parse_link_dest(ctx, doc, dest);
		return pdf_resolve_link(ctx, doc, uri, xp, yp);
	}

	if (!strncmp(name, "page=", 5))
		return fz_atoi(name + 5) - 1;

	return fz_atoi(name) - 1;
}

static void
pdf_flatten_inheritable_page_item(fz_context *ctx, pdf_obj *page, pdf_obj *key)
{
	pdf_obj *val = pdf_dict_get_inheritable(ctx, page, key);
	if (val)
		pdf_dict_put(ctx, page, key, val);
}

void
pdf_flatten_inheritable_page_items(fz_context *ctx, pdf_obj *page)
{
	pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(MediaBox));
	pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(CropBox));
	pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(Rotate));
	pdf_flatten_inheritable_page_item(ctx, page, PDF_NAME(Resources));
}

/* We need to know whether to install a page-level transparency group */

/*
 * Object memo flags - allows us to secretly remember "a memo" (a bool) in an
 * object, and to read back whether there was a memo, and if so, what it was.
 */
enum
{
	PDF_FLAGS_MEMO_BM = 0,
	PDF_FLAGS_MEMO_OP = 1
};

static int pdf_resources_use_blending(fz_context *ctx, pdf_obj *rdb);

static int
pdf_extgstate_uses_blending(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(BM));
	if (obj && !pdf_name_eq(ctx, obj, PDF_NAME(Normal)))
		return 1;
	return 0;
}

static int
pdf_pattern_uses_blending(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *obj;
	obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
	if (pdf_resources_use_blending(ctx, obj))
		return 1;
	obj = pdf_dict_get(ctx, dict, PDF_NAME(ExtGState));
	return pdf_extgstate_uses_blending(ctx, obj);
}

static int
pdf_xobject_uses_blending(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
	if (pdf_name_eq(ctx, pdf_dict_getp(ctx, dict, "Group/S"), PDF_NAME(Transparency)))
		return 1;
	return pdf_resources_use_blending(ctx, obj);
}

static int
pdf_resources_use_blending(fz_context *ctx, pdf_obj *rdb)
{
	pdf_obj *obj;
	int i, n, useBM = 0;

	if (!rdb)
		return 0;

	/* Have we been here before and remembered an answer? */
	if (pdf_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_BM, &useBM))
		return useBM;

	/* stop on cyclic resource dependencies */
	if (pdf_mark_obj(ctx, rdb))
		return 0;

	fz_try(ctx)
	{
		obj = pdf_dict_get(ctx, rdb, PDF_NAME(ExtGState));
		n = pdf_dict_len(ctx, obj);
		for (i = 0; i < n; i++)
			if (pdf_extgstate_uses_blending(ctx, pdf_dict_get_val(ctx, obj, i)))
				goto found;

		obj = pdf_dict_get(ctx, rdb, PDF_NAME(Pattern));
		n = pdf_dict_len(ctx, obj);
		for (i = 0; i < n; i++)
			if (pdf_pattern_uses_blending(ctx, pdf_dict_get_val(ctx, obj, i)))
				goto found;

		obj = pdf_dict_get(ctx, rdb, PDF_NAME(XObject));
		n = pdf_dict_len(ctx, obj);
		for (i = 0; i < n; i++)
			if (pdf_xobject_uses_blending(ctx, pdf_dict_get_val(ctx, obj, i)))
				goto found;
		if (0)
		{
found:
			useBM = 1;
		}
	}
	fz_always(ctx)
	{
		pdf_unmark_obj(ctx, rdb);
	}
	fz_catch(ctx)
	{
		fz_rethrow(ctx);
	}

	pdf_set_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_BM, useBM);
	return useBM;
}

static int pdf_resources_use_overprint(fz_context *ctx, pdf_obj *rdb);

static int
pdf_extgstate_uses_overprint(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(OP));
	if (obj && pdf_to_bool(ctx, obj))
		return 1;
	return 0;
}

static int
pdf_pattern_uses_overprint(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *obj;
	obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
	if (pdf_resources_use_overprint(ctx, obj))
		return 1;
	obj = pdf_dict_get(ctx, dict, PDF_NAME(ExtGState));
	return pdf_extgstate_uses_overprint(ctx, obj);
}

static int
pdf_xobject_uses_overprint(fz_context *ctx, pdf_obj *dict)
{
	pdf_obj *obj = pdf_dict_get(ctx, dict, PDF_NAME(Resources));
	return pdf_resources_use_overprint(ctx, obj);
}

static int
pdf_resources_use_overprint(fz_context *ctx, pdf_obj *rdb)
{
	pdf_obj *obj;
	int i, n, useOP = 0;

	if (!rdb)
		return 0;

	/* Have we been here before and remembered an answer? */
	if (pdf_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_OP, &useOP))
		return useOP;

	/* stop on cyclic resource dependencies */
	if (pdf_mark_obj(ctx, rdb))
		return 0;

	fz_try(ctx)
	{
		obj = pdf_dict_get(ctx, rdb, PDF_NAME(ExtGState));
		n = pdf_dict_len(ctx, obj);
		for (i = 0; i < n; i++)
			if (pdf_extgstate_uses_overprint(ctx, pdf_dict_get_val(ctx, obj, i)))
				goto found;

		obj = pdf_dict_get(ctx, rdb, PDF_NAME(Pattern));
		n = pdf_dict_len(ctx, obj);
		for (i = 0; i < n; i++)
			if (pdf_pattern_uses_overprint(ctx, pdf_dict_get_val(ctx, obj, i)))
				goto found;

		obj = pdf_dict_get(ctx, rdb, PDF_NAME(XObject));
		n = pdf_dict_len(ctx, obj);
		for (i = 0; i < n; i++)
			if (pdf_xobject_uses_overprint(ctx, pdf_dict_get_val(ctx, obj, i)))
				goto found;
		if (0)
		{
found:
			useOP = 1;
		}
	}
	fz_always(ctx)
	{
		pdf_unmark_obj(ctx, rdb);
	}
	fz_catch(ctx)
	{
		fz_rethrow(ctx);
	}

	pdf_set_obj_memo(ctx, rdb, PDF_FLAGS_MEMO_OP, useOP);
	return useOP;
}

fz_transition *
pdf_page_presentation(fz_context *ctx, pdf_page *page, fz_transition *transition, float *duration)
{
	pdf_obj *obj, *transdict;

	*duration = pdf_dict_get_real(ctx, page->obj, PDF_NAME(Dur));

	transdict = pdf_dict_get(ctx, page->obj, PDF_NAME(Trans));
	if (!transdict)
		return NULL;

	obj = pdf_dict_get(ctx, transdict, PDF_NAME(D));

	transition->duration = (obj ? pdf_to_real(ctx, obj) : 1);

	transition->vertical = !pdf_name_eq(ctx, pdf_dict_get(ctx, transdict, PDF_NAME(Dm)), PDF_NAME(H));
	transition->outwards = !pdf_name_eq(ctx, pdf_dict_get(ctx, transdict, PDF_NAME(M)), PDF_NAME(I));
	/* FIXME: If 'Di' is None, it should be handled differently, but
	 * this only affects Fly, and we don't implement that currently. */
	transition->direction = (pdf_dict_get_int(ctx, transdict, PDF_NAME(Di)));
	/* FIXME: Read SS for Fly when we implement it */
	/* FIXME: Read B for Fly when we implement it */

	obj = pdf_dict_get(ctx, transdict, PDF_NAME(S));
	if (pdf_name_eq(ctx, obj, PDF_NAME(Split)))
		transition->type = FZ_TRANSITION_SPLIT;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Blinds)))
		transition->type = FZ_TRANSITION_BLINDS;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Box)))
		transition->type = FZ_TRANSITION_BOX;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Wipe)))
		transition->type = FZ_TRANSITION_WIPE;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Dissolve)))
		transition->type = FZ_TRANSITION_DISSOLVE;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Glitter)))
		transition->type = FZ_TRANSITION_GLITTER;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Fly)))
		transition->type = FZ_TRANSITION_FLY;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Push)))
		transition->type = FZ_TRANSITION_PUSH;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Cover)))
		transition->type = FZ_TRANSITION_COVER;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Uncover)))
		transition->type = FZ_TRANSITION_UNCOVER;
	else if (pdf_name_eq(ctx, obj, PDF_NAME(Fade)))
		transition->type = FZ_TRANSITION_FADE;
	else
		transition->type = FZ_TRANSITION_NONE;

	return transition;
}

fz_rect
pdf_bound_page(fz_context *ctx, pdf_page *page)
{
	fz_matrix page_ctm;
	fz_rect mediabox;
	pdf_page_transform(ctx, page, &mediabox, &page_ctm);
	return fz_transform_rect(mediabox, page_ctm);
}

fz_link *
pdf_load_links(fz_context *ctx, pdf_page *page)
{
	return fz_keep_link(ctx, page->links);
}

pdf_obj *
pdf_page_resources(fz_context *ctx, pdf_page *page)
{
	return pdf_dict_get_inheritable(ctx, page->obj, PDF_NAME(Resources));
}

pdf_obj *
pdf_page_contents(fz_context *ctx, pdf_page *page)
{
	return pdf_dict_get(ctx, page->obj, PDF_NAME(Contents));
}

pdf_obj *
pdf_page_group(fz_context *ctx, pdf_page *page)
{
	return pdf_dict_get(ctx, page->obj, PDF_NAME(Group));
}

void
pdf_page_obj_transform(fz_context *ctx, pdf_obj *pageobj, fz_rect *page_mediabox, fz_matrix *page_ctm)
{
	pdf_obj *obj;
	fz_rect mediabox, cropbox, realbox, pagebox;
	float userunit = 1;
	int rotate;

	if (!page_mediabox)
		page_mediabox = &pagebox;

	obj = pdf_dict_get(ctx, pageobj, PDF_NAME(UserUnit));
	if (pdf_is_real(ctx, obj))
		userunit = pdf_to_real(ctx, obj);

	mediabox = pdf_to_rect(ctx, pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(MediaBox)));
	if (fz_is_empty_rect(mediabox))
	{
		mediabox.x0 = 0;
		mediabox.y0 = 0;
		mediabox.x1 = 612;
		mediabox.y1 = 792;
	}

	cropbox = pdf_to_rect(ctx, pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(CropBox)));
	if (!fz_is_empty_rect(cropbox))
		mediabox = fz_intersect_rect(mediabox, cropbox);

	page_mediabox->x0 = fz_min(mediabox.x0, mediabox.x1);
	page_mediabox->y0 = fz_min(mediabox.y0, mediabox.y1);
	page_mediabox->x1 = fz_max(mediabox.x0, mediabox.x1);
	page_mediabox->y1 = fz_max(mediabox.y0, mediabox.y1);

	if (page_mediabox->x1 - page_mediabox->x0 < 1 || page_mediabox->y1 - page_mediabox->y0 < 1)
		*page_mediabox = fz_unit_rect;

	rotate = pdf_to_int(ctx, pdf_dict_get_inheritable(ctx, pageobj, PDF_NAME(Rotate)));

	/* Snap page rotation to 0, 90, 180 or 270 */
	if (rotate < 0)
		rotate = 360 - ((-rotate) % 360);
	if (rotate >= 360)
		rotate = rotate % 360;
	rotate = 90*((rotate + 45)/90);
	if (rotate >= 360)
		rotate = 0;

	/* Compute transform from fitz' page space (upper left page origin, y descending, 72 dpi)
	 * to PDF user space (arbitrary page origin, y ascending, UserUnit dpi). */

	/* Make left-handed and scale by UserUnit */
	*page_ctm = fz_scale(userunit, -userunit);

	/* Rotate */
	*page_ctm = fz_pre_rotate(*page_ctm, -rotate);

	/* Translate page origin to 0,0 */
	realbox = fz_transform_rect(*page_mediabox, *page_ctm);
	*page_ctm = fz_concat(*page_ctm, fz_translate(-realbox.x0, -realbox.y0));
}

void
pdf_page_transform(fz_context *ctx, pdf_page *page, fz_rect *page_mediabox, fz_matrix *page_ctm)
{
	pdf_page_obj_transform(ctx, page->obj, page_mediabox, page_ctm);
}

static void
find_seps(fz_context *ctx, fz_separations **seps, pdf_obj *obj, pdf_obj *clearme)
{
	int i, n;
	pdf_obj *nameobj, *cols;

	nameobj = pdf_array_get(ctx, obj, 0);
	if (pdf_name_eq(ctx, nameobj, PDF_NAME(Separation)))
	{
		fz_colorspace *cs;
		const char *name = pdf_to_name(ctx, pdf_array_get(ctx, obj, 1));

		/* Skip 'special' colorants. */
		if (!strcmp(name, "Black") ||
			!strcmp(name, "Cyan") ||
			!strcmp(name, "Magenta") ||
			!strcmp(name, "Yellow") ||
			!strcmp(name, "All") ||
			!strcmp(name, "None"))
			return;

		n = fz_count_separations(ctx, *seps);
		for (i = 0; i < n; i++)
		{
			if (!strcmp(name, fz_separation_name(ctx, *seps, i)))
				return; /* Got that one already */
		}

		fz_try(ctx)
			cs = pdf_load_colorspace(ctx, obj);
		fz_catch(ctx)
		{
			fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
			return; /* ignore broken colorspace */
		}
		fz_try(ctx)
		{
			if (!*seps)
				*seps = fz_new_separations(ctx, 0);
			fz_add_separation(ctx, *seps, name, cs, 0);
		}
		fz_always(ctx)
			fz_drop_colorspace(ctx, cs);
		fz_catch(ctx)
			fz_rethrow(ctx);
	}
	else if (pdf_name_eq(ctx, nameobj, PDF_NAME(Indexed)))
	{
		if (pdf_is_indirect(ctx, obj))
		{
			if (pdf_mark_obj(ctx, obj))
				return; /* already been here */
			/* remember to clear this colorspace dictionary at the end */
			pdf_array_push(ctx, clearme, obj);
		}

		find_seps(ctx, seps, pdf_array_get(ctx, obj, 1), clearme);
	}
	else if (pdf_name_eq(ctx, nameobj, PDF_NAME(DeviceN)))
	{
		if (pdf_is_indirect(ctx, obj))
		{
			if (pdf_mark_obj(ctx, obj))
				return; /* already been here */
			/* remember to clear this colorspace dictionary at the end */
			pdf_array_push(ctx, clearme, obj);
		}

		/* If the separation colorants exists for this DeviceN color space
		 * add those prior to our search for DeviceN color */
		cols = pdf_dict_get(ctx, pdf_array_get(ctx, obj, 4), PDF_NAME(Colorants));
		n = pdf_dict_len(ctx, cols);
		for (i = 0; i < n; i++)
			find_seps(ctx, seps, pdf_dict_get_val(ctx, cols, i), clearme);
	}
}

static void
find_devn(fz_context *ctx, fz_separations **seps, pdf_obj *obj, pdf_obj *clearme)
{
	int i, j, n, m;
	pdf_obj *arr;
	pdf_obj *nameobj = pdf_array_get(ctx, obj, 0);

	if (!pdf_name_eq(ctx, nameobj, PDF_NAME(DeviceN)))
		return;

	arr = pdf_array_get(ctx, obj, 1);
	m = pdf_array_len(ctx, arr);
	for (j = 0; j < m; j++)
	{
		fz_colorspace *cs;
		const char *name = pdf_to_name(ctx, pdf_array_get(ctx, arr, j));

		/* Skip 'special' colorants. */
		if (!strcmp(name, "Black") ||
			!strcmp(name, "Cyan") ||
			!strcmp(name, "Magenta") ||
			!strcmp(name, "Yellow") ||
			!strcmp(name, "All") ||
			!strcmp(name, "None"))
			continue;

		n = fz_count_separations(ctx, *seps);
		for (i = 0; i < n; i++)
		{
			if (!strcmp(name, fz_separation_name(ctx, *seps, i)))
				break; /* Got that one already */
		}

		if (i == n)
		{
			fz_try(ctx)
				cs = pdf_load_colorspace(ctx, obj);
			fz_catch(ctx)
			{
				fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
				continue; /* ignore broken colorspace */
			}
			fz_try(ctx)
			{
				if (!*seps)
					*seps = fz_new_separations(ctx, 0);
				fz_add_separation(ctx, *seps, name, cs, j);
			}
			fz_always(ctx)
				fz_drop_colorspace(ctx, cs);
			fz_catch(ctx)
				fz_rethrow(ctx);
		}
	}
}

typedef void (res_finder_fn)(fz_context *ctx, fz_separations **seps, pdf_obj *obj, pdf_obj *clearme);

static void
scan_page_seps(fz_context *ctx, pdf_obj *res, fz_separations **seps, res_finder_fn *fn, pdf_obj *clearme)
{
	pdf_obj *dict;
	pdf_obj *obj;
	int i, n;

	if (pdf_mark_obj(ctx, res))
		return; /* already been here */

	/* remember to clear this resource dictionary at the end */
	pdf_array_push(ctx, clearme, res);

	dict = pdf_dict_get(ctx, res, PDF_NAME(ColorSpace));
	n = pdf_dict_len(ctx, dict);
	for (i = 0; i < n; i++)
	{
		obj = pdf_dict_get_val(ctx, dict, i);
		fn(ctx, seps, obj, clearme);
	}

	dict = pdf_dict_get(ctx, res, PDF_NAME(Shading));
	n = pdf_dict_len(ctx, dict);
	for (i = 0; i < n; i++)
	{
		obj = pdf_dict_get_val(ctx, dict, i);
		fn(ctx, seps, pdf_dict_get(ctx, obj, PDF_NAME(ColorSpace)), clearme);
	}

	dict = pdf_dict_get(ctx, res, PDF_NAME(XObject));
	n = pdf_dict_len(ctx, dict);
	for (i = 0; i < n; i++)
	{
		obj = pdf_dict_get_val(ctx, dict, i);
		fn(ctx, seps, pdf_dict_get(ctx, obj, PDF_NAME(ColorSpace)), clearme);
		/* Recurse on XObject forms. */
		scan_page_seps(ctx, pdf_dict_get(ctx, obj, PDF_NAME(Resources)), seps, fn, clearme);
	}
}

fz_separations *
pdf_page_separations(fz_context *ctx, pdf_page *page)
{
	pdf_obj *res = pdf_page_resources(ctx, page);
	pdf_obj *clearme = NULL;
	fz_separations *seps = NULL;

	clearme = pdf_new_array(ctx, page->doc, 100);
	fz_try(ctx)
	{
		/* Run through and look for separations first. This is
		 * because separations are simplest to deal with, and
		 * because DeviceN may be implemented on top of separations.
		 */
		scan_page_seps(ctx, res, &seps, find_seps, clearme);
	}
	fz_always(ctx)
	{
		int i, n = pdf_array_len(ctx, clearme);
		for (i = 0; i < n; ++i)
			pdf_unmark_obj(ctx, pdf_array_get(ctx, clearme, i));
		pdf_drop_obj(ctx, clearme);
	}
	fz_catch(ctx)
	{
		fz_drop_separations(ctx, seps);
		fz_rethrow(ctx);
	}

	clearme = pdf_new_array(ctx, page->doc, 100);
	fz_try(ctx)
	{
		/* Now run through again, and look for DeviceNs. These may
		 * have spot colors in that aren't defined in terms of
		 * separations. */
		scan_page_seps(ctx, res, &seps, find_devn, clearme);
	}
	fz_always(ctx)
	{
		int i, n = pdf_array_len(ctx, clearme);
		for (i = 0; i < n; ++i)
			pdf_unmark_obj(ctx, pdf_array_get(ctx, clearme, i));
		pdf_drop_obj(ctx, clearme);
	}
	fz_catch(ctx)
	{
		fz_drop_separations(ctx, seps);
		fz_rethrow(ctx);
	}

	return seps;
}

int
pdf_page_uses_overprint(fz_context *ctx, pdf_page *page)
{
	return page ? page->overprint : 0;
}

static void
pdf_drop_page_imp(fz_context *ctx, pdf_page *page)
{
	fz_drop_link(ctx, page->links);
	pdf_drop_annots(ctx, page->annots);
	pdf_drop_widgets(ctx, page->widgets);
	pdf_drop_obj(ctx, page->obj);
}

static pdf_page *
pdf_new_page(fz_context *ctx, pdf_document *doc)
{
	pdf_page *page = fz_new_derived_page(ctx, pdf_page, (fz_document*) doc);

	page->doc = doc; /* typecast alias for page->super.doc */

	page->super.drop_page = (fz_page_drop_page_fn*)pdf_drop_page_imp;
	page->super.load_links = (fz_page_load_links_fn*)pdf_load_links;
	page->super.bound_page = (fz_page_bound_page_fn*)pdf_bound_page;
	page->super.run_page_contents = (fz_page_run_page_fn*)pdf_run_page_contents;
	page->super.run_page_annots = (fz_page_run_page_fn*)pdf_run_page_annots;
	page->super.run_page_widgets = (fz_page_run_page_fn*)pdf_run_page_widgets;
	page->super.page_presentation = (fz_page_page_presentation_fn*)pdf_page_presentation;
	page->super.separations = (fz_page_separations_fn *)pdf_page_separations;
	page->super.overprint = (fz_page_uses_overprint_fn *)pdf_page_uses_overprint;
	page->super.create_link = (fz_page_create_link_fn *)pdf_create_link;

	page->obj = NULL;

	page->transparency = 0;
	page->links = NULL;
	page->annots = NULL;
	page->annot_tailp = &page->annots;
	page->widgets = NULL;
	page->widget_tailp = &page->widgets;

	return page;
}

static void
pdf_load_default_colorspaces_imp(fz_context *ctx, fz_default_colorspaces *default_cs, pdf_obj *obj)
{
	pdf_obj *cs_obj;

	/* The spec says to ignore any colors we can't understand */

	cs_obj = pdf_dict_get(ctx, obj, PDF_NAME(DefaultGray));
	if (cs_obj)
	{
		fz_try(ctx)
		{
			fz_colorspace *cs = pdf_load_colorspace(ctx, cs_obj);
			fz_set_default_gray(ctx, default_cs, cs);
			fz_drop_colorspace(ctx, cs);
		}
		fz_catch(ctx)
			fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
	}

	cs_obj = pdf_dict_get(ctx, obj, PDF_NAME(DefaultRGB));
	if (cs_obj)
	{
		fz_try(ctx)
		{
			fz_colorspace *cs = pdf_load_colorspace(ctx, cs_obj);
			fz_set_default_rgb(ctx, default_cs, cs);
			fz_drop_colorspace(ctx, cs);
		}
		fz_catch(ctx)
			fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
	}

	cs_obj = pdf_dict_get(ctx, obj, PDF_NAME(DefaultCMYK));
	if (cs_obj)
	{
		fz_try(ctx)
		{
			fz_colorspace *cs = pdf_load_colorspace(ctx, cs_obj);
			fz_set_default_cmyk(ctx, default_cs, cs);
			fz_drop_colorspace(ctx, cs);
		}
		fz_catch(ctx)
			fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
	}
}

fz_default_colorspaces *
pdf_load_default_colorspaces(fz_context *ctx, pdf_document *doc, pdf_page *page)
{
	pdf_obj *res;
	pdf_obj *obj;
	fz_default_colorspaces *default_cs;
	fz_colorspace *oi;

	default_cs = fz_new_default_colorspaces(ctx);

	fz_try(ctx)
	{
		res = pdf_page_resources(ctx, page);
		obj = pdf_dict_get(ctx, res, PDF_NAME(ColorSpace));
		if (obj)
			pdf_load_default_colorspaces_imp(ctx, default_cs, obj);

		oi = pdf_document_output_intent(ctx, doc);
		if (oi)
			fz_set_default_output_intent(ctx, default_cs, oi);
	}
	fz_catch(ctx)
	{
		if (fz_caught(ctx) != FZ_ERROR_TRYLATER)
		{
			fz_drop_default_colorspaces(ctx, default_cs);
			fz_rethrow(ctx);
		}
		page->super.incomplete = 1;
	}

	return default_cs;
}

fz_default_colorspaces *
pdf_update_default_colorspaces(fz_context *ctx, fz_default_colorspaces *old_cs, pdf_obj *res)
{
	pdf_obj *obj;
	fz_default_colorspaces *new_cs;

	obj = pdf_dict_get(ctx, res, PDF_NAME(ColorSpace));
	if (!obj)
		return fz_keep_default_colorspaces(ctx, old_cs);

	new_cs = fz_clone_default_colorspaces(ctx, old_cs);
	fz_try(ctx)
		pdf_load_default_colorspaces_imp(ctx, new_cs, obj);
	fz_catch(ctx)
	{
		fz_drop_default_colorspaces(ctx, new_cs);
		fz_rethrow(ctx);
	}

	return new_cs;
}

pdf_page *
pdf_load_page(fz_context *ctx, pdf_document *doc, int number)
{
	return (pdf_page*)fz_load_page(ctx, (fz_document*)doc, number);
}

fz_page *
pdf_load_page_imp(fz_context *ctx, fz_document *doc_, int chapter, int number)
{
	pdf_document *doc = (pdf_document*)doc_;
	pdf_page *page;
	pdf_annot *annot;
	pdf_obj *pageobj, *obj;

	if (doc->file_reading_linearly)
	{
		pageobj = pdf_progressive_advance(ctx, doc, number);
		if (pageobj == NULL)
			fz_throw(ctx, FZ_ERROR_TRYLATER, "page %d not available yet", number);
	}
	else
		pageobj = pdf_lookup_page_obj(ctx, doc, number);

	page = pdf_new_page(ctx, doc);
	page->obj = pdf_keep_obj(ctx, pageobj);

	/* Pre-load annotations and links */
	fz_try(ctx)
	{
		obj = pdf_dict_get(ctx, pageobj, PDF_NAME(Annots));
		if (obj)
		{
			fz_rect page_mediabox;
			fz_matrix page_ctm;
			pdf_page_transform(ctx, page, &page_mediabox, &page_ctm);
			page->links = pdf_load_link_annots(ctx, doc, obj, number, page_ctm);
			pdf_load_annots(ctx, page, obj);
		}
	}
	fz_catch(ctx)
	{
		if (fz_caught(ctx) != FZ_ERROR_TRYLATER)
		{
			fz_drop_page(ctx, &page->super);
			fz_rethrow(ctx);
		}
		page->super.incomplete = 1;
		fz_drop_link(ctx, page->links);
		page->links = NULL;
	}

	/* Scan for transparency and overprint */
	fz_try(ctx)
	{
		pdf_obj *resources = pdf_page_resources(ctx, page);
		if (pdf_name_eq(ctx, pdf_dict_getp(ctx, pageobj, "Group/S"), PDF_NAME(Transparency)))
			page->transparency = 1;
		else if (pdf_resources_use_blending(ctx, resources))
			page->transparency = 1;
		if (pdf_resources_use_overprint(ctx, resources))
			page->overprint = 1;
		for (annot = page->annots; annot && !page->transparency; annot = annot->next)
		{
			fz_try(ctx)
			{
				pdf_obj *ap;
				pdf_obj *res;
				pdf_annot_push_local_xref(ctx, annot);
				ap = pdf_annot_ap(ctx, annot);
				if (!ap)
					break;
				res = pdf_xobject_resources(ctx, ap);
				if (pdf_resources_use_blending(ctx, res))
					page->transparency = 1;
				if (pdf_resources_use_overprint(ctx, pdf_xobject_resources(ctx, res)))
					page->overprint = 1;
			}
			fz_always(ctx)
				pdf_annot_pop_local_xref(ctx, annot);
			fz_catch(ctx)
				fz_rethrow(ctx);
		}
	}
	fz_catch(ctx)
	{
		if (fz_caught(ctx) != FZ_ERROR_TRYLATER)
		{
			fz_drop_page(ctx, &page->super);
			fz_rethrow(ctx);
		}
		page->super.incomplete = 1;
	}

	return (fz_page*)page;
}

void
pdf_delete_page(fz_context *ctx, pdf_document *doc, int at)
{
	pdf_obj *parent, *kids;
	int i;

	pdf_lookup_page_loc(ctx, doc, at, &parent, &i);
	kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
	pdf_array_delete(ctx, kids, i);

	while (parent)
	{
		int count = pdf_dict_get_int(ctx, parent, PDF_NAME(Count));
		pdf_dict_put_int(ctx, parent, PDF_NAME(Count), count - 1);
		parent = pdf_dict_get(ctx, parent, PDF_NAME(Parent));
	}
}

void
pdf_delete_page_range(fz_context *ctx, pdf_document *doc, int start, int end)
{
	int count = pdf_count_pages(ctx, doc);

	if (end < 0 || end > count)
		end = count+1;
	if (start < 0)
		start = 0;
	while (start < end)
	{
		pdf_delete_page(ctx, doc, start);
		end--;
	}
}

pdf_obj *
pdf_add_page(fz_context *ctx, pdf_document *doc, fz_rect mediabox, int rotate, pdf_obj *resources, fz_buffer *contents)
{
	pdf_obj *page_obj = pdf_new_dict(ctx, doc, 5);
	fz_try(ctx)
	{
		pdf_dict_put(ctx, page_obj, PDF_NAME(Type), PDF_NAME(Page));
		pdf_dict_put_rect(ctx, page_obj, PDF_NAME(MediaBox), mediabox);
		pdf_dict_put_int(ctx, page_obj, PDF_NAME(Rotate), rotate);

		if (pdf_is_indirect(ctx, resources))
			pdf_dict_put(ctx, page_obj, PDF_NAME(Resources), resources);
		else if (pdf_is_dict(ctx, resources))
			pdf_dict_put_drop(ctx, page_obj, PDF_NAME(Resources), pdf_add_object(ctx, doc, resources));
		else
			pdf_dict_put_dict(ctx, page_obj, PDF_NAME(Resources), 1);

		if (contents)
			pdf_dict_put_drop(ctx, page_obj, PDF_NAME(Contents), pdf_add_stream(ctx, doc, contents, NULL, 0));
	}
	fz_catch(ctx)
	{
		pdf_drop_obj(ctx, page_obj);
		fz_rethrow(ctx);
	}
	return pdf_add_object_drop(ctx, doc, page_obj);
}

void
pdf_insert_page(fz_context *ctx, pdf_document *doc, int at, pdf_obj *page_ref)
{
	int count = pdf_count_pages(ctx, doc);
	pdf_obj *parent, *kids;
	int i;

	if (at < 0)
		at = count;
	if (at == INT_MAX)
		at = count;
	if (at > count)
		fz_throw(ctx, FZ_ERROR_GENERIC, "cannot insert page beyond end of page tree");

	if (count == 0)
	{
		pdf_obj *root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
		parent = pdf_dict_get(ctx, root, PDF_NAME(Pages));
		if (!parent)
			fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find page tree");
		kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
		if (!kids)
			fz_throw(ctx, FZ_ERROR_GENERIC, "malformed page tree");
		pdf_array_insert(ctx, kids, page_ref, 0);
	}
	else if (at == count)
	{
		/* append after last page */
		pdf_lookup_page_loc(ctx, doc, count - 1, &parent, &i);
		kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
		pdf_array_insert(ctx, kids, page_ref, i + 1);
	}
	else
	{
		/* insert before found page */
		pdf_lookup_page_loc(ctx, doc, at, &parent, &i);
		kids = pdf_dict_get(ctx, parent, PDF_NAME(Kids));
		pdf_array_insert(ctx, kids, page_ref, i);
	}

	pdf_dict_put(ctx, page_ref, PDF_NAME(Parent), parent);

	/* Adjust page counts */
	while (parent)
	{
		count = pdf_dict_get_int(ctx, parent, PDF_NAME(Count));
		pdf_dict_put_int(ctx, parent, PDF_NAME(Count), count + 1);
		parent = pdf_dict_get(ctx, parent, PDF_NAME(Parent));
	}
}
