/*
 * Copyright 2012 - 2013 Michael Drake <tlsa@netsurf-browser.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/** \file
 * Treeview handling (interface).
 */

#ifndef _NETSURF_DESKTOP_TREEVIEW_H_
#define _NETSURF_DESKTOP_TREEVIEW_H_

#include <stdbool.h>
#include <stdint.h>

#include "desktop/mouse.h"
#include "desktop/core_window.h"
#include "desktop/textinput.h"

struct redraw_context;

typedef struct treeview treeview;
typedef struct treeview_node treeview_node;

enum treeview_node_type {
	TREE_NODE_NONE		= 0,		/**< No node  */
	TREE_NODE_ROOT		= (1 << 0),	/**< Node is treeview's root */
	TREE_NODE_FOLDER	= (1 << 1),	/**< Node is folder */
	TREE_NODE_ENTRY		= (1 << 2)	/**< Node is an entry */
};

enum treeview_relationship {
	TREE_REL_FIRST_CHILD,
	TREE_REL_NEXT_SIBLING
};					/**< Relationship between nodes */

typedef enum {
	TREE_OPTION_NONE		= (0),		/* No flags set */
	TREE_OPTION_SPECIAL_DIR		= (1 << 0),	/* Special folder */
	TREE_OPTION_SUPPRESS_RESIZE	= (1 << 1),	/* Suppress callback */
	TREE_OPTION_SUPPRESS_REDRAW	= (1 << 2)	/* Suppress callback */
} treeview_node_options_flags;		/**< Node change handling options */

typedef enum {
	TREEVIEW_NO_FLAGS	= (0),		/**< No flags set */
	TREEVIEW_NO_MOVES	= (1 << 0),	/**< No node drags */
	TREEVIEW_NO_DELETES	= (1 << 1),	/**< No node deletes */
	TREEVIEW_READ_ONLY	= TREEVIEW_NO_MOVES | TREEVIEW_NO_DELETES,
	TREEVIEW_DEL_EMPTY_DIRS	= (1 << 2)	/**< Delete dirs on empty */
} treeview_flags;

enum treeview_msg {
	TREE_MSG_NODE_DELETE,		/**< Node to be deleted */
	TREE_MSG_NODE_EDIT,		/**< Node to be edited */
	TREE_MSG_NODE_LAUNCH		/**< Node to be launched */
};
struct treeview_node_msg {
	enum treeview_msg msg; /**< The message type */
	union {
		struct {
			bool user; /* True iff delete by user interaction */
		} delete;
		struct {
			lwc_string *field; /* The field being edited */
			const char *text;  /* The proposed new value */
		} node_edit; /* Client may call treeview_update_node_* */
		struct {
			browser_mouse_state mouse; /* Button / modifier used */
		} node_launch;
	} data; /**< The message data. */
};

enum treeview_field_flags {
	TREE_FLAG_NONE		= 0,		/**< No flags set */
	TREE_FLAG_ALLOW_EDIT	= (1 << 0),	/**< Whether allow edit field */
	TREE_FLAG_DEFAULT	= (1 << 1),	/**< Whether field is default */
	TREE_FLAG_SHOW_NAME	= (1 << 2),	/**< Whether field name shown */
	TREE_FLAG_COPY_TEXT	= (1 << 3)	/**< Whether to copy to clipb */
};
struct treeview_field_desc {
	lwc_string *field;			/**< A treeview field name */
	enum treeview_field_flags flags;	/**< Flags for field */
}; /**< Treeview field description */

struct treeview_field_data {
	lwc_string *field;		/**< Field name */
	const char *value;		/**< Field value */
	size_t value_len;		/**< Field value length (bytes) */
};


struct treeview_callback_table {
	nserror (*folder)(struct treeview_node_msg msg, void *data);
	nserror (*entry)(struct treeview_node_msg msg, void *data);
}; /**< Client callbacks for events concerning nodes */

/**
 * Prepare treeview module for treeview usage
 *
 * \param font_pt_size	Treeview text size in pt.  Set to <= 0 for default.
 * \return NSERROR_OK on success, appropriate error otherwise
 */
nserror treeview_init(int font_pt_size);

/**
 * Finalise the treeview module (all treeviews must have been destroyed first)
 *
 * \return NSERROR_OK on success, appropriate error otherwise
 */
nserror treeview_fini(void);

/**
 * Create a treeview
 *
 * \param tree		Returns created treeview object
 * \param callbacks	Treeview client node event callbacks
 * \param n_fields	Number of treeview fields (see description)
 * \param fields	Array of treeview fields
 * \param cw_t		Callback table for core_window containing the treeview
 * \param cw		The core_window in which the treeview is shown
 * \param flags		Treeview behaviour flags
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * The fields array order is as follows (N = n_fields):
 *
 *    fields[0]			Main field for entries (shown when not expanded)
 *    fields[1]...fields[N-2]	Additional fields for entries
 *    fields[N-1]		Field for folder nodes
 *
 * So fields[0] and fields[N-1] have TREE_FLAG_DEFAULT set.
 */
nserror treeview_create(treeview **tree,
		const struct treeview_callback_table *callbacks,
		int n_fields, struct treeview_field_desc fields[],
		const struct core_window_callback_table *cw_t,
		struct core_window *cw, treeview_flags flags);

/**
 * Destroy a treeview object
 *
 * \param tree		Treeview object to destroy
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Will emit folder and entry deletion msg callbacks for all nodes in treeview.
 */
nserror treeview_destroy(treeview *tree);

/**
 * Find a releation for node creation.
 *
 * \param tree		Treeview object in which to create folder
 * \param relation	Existing node to insert as relation of, or NULL
 * \param rel		Folder's relationship to relation
 * \param at_y		Iff true, insert at y-offest
 * \param y		Y-offset in px from top of hotlist.  Ignored if (!at_y).
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * If at_y is set, we find a relation that will put the created node at that
 * position.
 *
 * If at_y is unset, we find a relation that would put the node below the first
 * selected node, or at the end of the treeview if no nodes selected.
 */
nserror treeview_get_relation(treeview *tree, treeview_node **relation,
		enum treeview_relationship *rel, bool at_y, int y);

/**
 * Create a folder node in given treeview
 *
 * \param tree		Treeview object in which to create folder
 * \param folder	Returns created folder node
 * \param relation	Existing node to insert as relation of, or NULL
 * \param rel		Folder's relationship to relation
 * \param field		Field data
 * \param data		Client data for node event callbacks
 * \param flags		Treeview node options flags
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Field name must match name past in treeview_create fields[N-1].
 *
 * If relation is NULL, will insert as child of root node.
 */
nserror treeview_create_node_folder(treeview *tree,
		treeview_node **folder,
		treeview_node *relation,
		enum treeview_relationship rel,
		const struct treeview_field_data *field,
		void *data, treeview_node_options_flags flags);

/**
 * Create an entry node in given treeview
 *
 * \param tree		Treeview object in which to create entry
 * \param entry		Returns created entry node
 * \param relation	Existing node to insert as relation of, or NULL
 * \param rel		Folder's relationship to relation
 * \param fields	Array of field data
 * \param data		Client data for node event callbacks
 * \param flags		Treeview node options flags
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Fields array names must match names past in treeview_create fields[0...N-2].
 *
 * If relation is NULL, will insert as child of root node.
 */
nserror treeview_create_node_entry(treeview *tree,
		treeview_node **entry,
		treeview_node *relation,
		enum treeview_relationship rel,
		const struct treeview_field_data fields[],
		void *data, treeview_node_options_flags flags);

/**
 * Update an folder node in given treeview
 *
 * \param tree	 Treeview object in which to create entry
 * \param folder Folder node to update
 * \param field	 New field data
 * \param data	 Client data for node event callbacks
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Field name must match name past in treeview_create fields[N-1].
 */
nserror treeview_update_node_folder(treeview *tree,
		treeview_node *folder,
		const struct treeview_field_data *field,
		void *data);

/**
 * Update an entry node in given treeview
 *
 * \param tree		Treeview object in which to create entry
 * \param entry		Entry node to update
 * \param fields	Array of new field data
 * \param data		Client data for node event callbacks
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Fields array names must match names past in treeview_create fields[0...N-2].
 */
nserror treeview_update_node_entry(treeview *tree,
		treeview_node *entry,
		const struct treeview_field_data fields[],
		void *data);


/**
 * Client callback for treeview_walk
 *
 * \param ctx		Client context
 * \param node_data	Client data for the current treeview node
 * \param type		The node type
 * \param abort		Set to true to abort treeview walk prematurely
 * \return NSERROR_OK on success, or appropriate error otherwise
 */
typedef nserror (*treeview_walk_cb)(void *ctx, void *node_data,
		enum treeview_node_type type, bool *abort);

/**
 * Walk (depth first) a treeview subtree, calling a callback at each node of
 * required type.
 *
 * \param tree		Treeview object to walk
 * \param root		Root node to walk tree from (or NULL for tree root)
 * \param enter_cb	Function to call on entering nodes, or NULL
 * \param leave_cb	Function to call on leaving nodes, or NULL
 * \param ctx		Client context, passed back to callback function
 * \param type		The node type(s) of interest
 * \return NSERROR_OK on success, or appropriate error otherwise
 *
 * Example usage: To export a treeview as XML, XML elements can be opened in
 * enter_cb, and closed in leave_cb.
 *
 * Note, if deleting returned node in enter_cb, the walk must be terminated by
 * setting abort to true.
 */
nserror treeview_walk(treeview *tree, treeview_node *root,
		treeview_walk_cb enter_cb, treeview_walk_cb leave_cb,
		void *ctx, enum treeview_node_type type);

/**
 * Delete a treeview node
 *
 * \param tree		Treeview object to delete node from
 * \param n		Node to delete
 * \param flags		Treeview node options flags
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Will emit folder or entry deletion msg callback.
 */
nserror treeview_delete_node(treeview *tree, treeview_node *n,
		treeview_node_options_flags flags);

/**
 * Expand a treeview node
 *
 * \param tree		Treeview object to expand node in
 * \param node		Node to expand
 * \return NSERROR_OK on success, appropriate error otherwise
 */
nserror treeview_node_expand(treeview *tree, treeview_node *node);

/**
 * Contract a treeview node
 *
 * \param tree		Treeview object to contract node in
 * \param node		Node to contract
 * \return NSERROR_OK on success, appropriate error otherwise
 */
nserror treeview_node_contract(treeview *tree, treeview_node *node);

/**
 * Expand a treeview's nodes
 *
 * \param tree		Treeview object to expand nodes in
 * \param only_folders	Iff true, only folders are expanded.
 * \return NSERROR_OK on success, appropriate error otherwise
 */
nserror treeview_expand(treeview *tree, bool only_folders);

/**
 * Contract a treeview's nodes
 *
 * \param tree		Treeview object to contract nodes in
 * \param all		Iff false, only entries are contracted.
 * \return NSERROR_OK on success, appropriate error otherwise
 */
nserror treeview_contract(treeview *tree, bool all);

/**
 * Redraw a treeview object
 *
 * \param tree		Treeview object to render
 * \param x		X coordinate to render treeview at
 * \param y		Y coordinate to render treeview at
 * \param clip		Current clip rectangle (wrt tree origin)
 * \param ctx		Current redraw context
 */
void treeview_redraw(treeview *tree, int x, int y, struct rect *clip,
		const struct redraw_context *ctx);

/**
 * Key press handling for treeviews.
 *
 * \param tree		The treeview which got the keypress
 * \param key		The ucs4 character codepoint
 * \return true if the keypress is dealt with, false otherwise.
 */
bool treeview_keypress(treeview *tree, uint32_t key);

/**
 * Handles all kinds of mouse action
 *
 * \param tree		Treeview object
 * \param mouse		The current mouse state
 * \param x		X coordinate
 * \param y		Y coordinate
 */
void treeview_mouse_action(treeview *tree,
		browser_mouse_state mouse, int x, int y);

/**
 * Determine whether treeview has a selection
 *
 * \param tree		Treeview object to delete node from
 * \return true iff treeview has a selection
 */
bool treeview_has_selection(treeview *tree);

/**
 * Get the first selected node
 *
 * \param tree		Treeview object to get selected node in
 * \param node_data	Client data for the selected treeview node, or NULL
 * \return node type of first selected node.
 */
enum treeview_node_type treeview_get_selection(treeview *tree,
		void **node_data);

/**
 * Edit the first selected node
 *
 * \param tree		Treeview object to edit selected node in
 */
void treeview_edit_selection(treeview *tree);

/**
 * Find current height of a treeview
 *
 * \param tree		Treeview object to find height of
 * \return height of treeview in px
 */
int treeview_get_height(treeview *tree);

#endif
