// Wrapper around the notmuch library

package notmuch

/*
#cgo LDFLAGS: -lnotmuch

#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "notmuch.h"
*/
import "C"
import "unsafe"

// Status codes used for the return values of most functions
type Status C.notmuch_status_t

const (
	STATUS_SUCCESS Status = iota
	STATUS_OUT_OF_MEMORY
	STATUS_READ_ONLY_DATABASE
	STATUS_XAPIAN_EXCEPTION
	STATUS_FILE_ERROR
	STATUS_FILE_NOT_EMAIL
	STATUS_DUPLICATE_MESSAGE_ID
	STATUS_NULL_POINTER
	STATUS_TAG_TOO_LONG
	STATUS_UNBALANCED_FREEZE_THAW
	STATUS_UNBALANCED_ATOMIC

	STATUS_LAST_STATUS
)

func (self Status) String() string {
	var p *C.char

	// p is read-only
	p = C.notmuch_status_to_string(C.notmuch_status_t(self))
	if p != nil {
		s := C.GoString(p)
		return s
	}
	return ""
}

type Database struct {
	db *C.notmuch_database_t
}

type Query struct {
	query *C.notmuch_query_t
}

type Threads struct {
	threads *C.notmuch_threads_t
}

type Thread struct {
	thread *C.notmuch_thread_t
}

type Messages struct {
	messages *C.notmuch_messages_t
}

type Message struct {
	message *C.notmuch_message_t
}

type Tags struct {
	tags *C.notmuch_tags_t
}

type Directory struct {
	dir *C.notmuch_directory_t
}

type Filenames struct {
	fnames *C.notmuch_filenames_t
}

type DatabaseMode C.notmuch_database_mode_t

const (
	DATABASE_MODE_READ_ONLY DatabaseMode = 0
	DATABASE_MODE_READ_WRITE
)

// Create a new, empty notmuch database located at 'path'
func NewDatabase(path string) (*Database, Status) {

	var c_path *C.char = C.CString(path)
	defer C.free(unsafe.Pointer(c_path))

	if c_path == nil {
		return nil, STATUS_OUT_OF_MEMORY
	}

	self := &Database{db: nil}
	st := Status(C.notmuch_database_create(c_path, &self.db))
	if st != STATUS_SUCCESS {
		return nil, st
	}
	return self, st
}

// Open an existing notmuch database located at 'path'. By default the
// database should be opened for reading only
// (NOTMUCH_STATUS_READ_ONLY_DATABASE). In order to write to the
// database you need to pass the NOTMUCH_DATABASE_MODE_READ_WRITE
// mode.
func OpenDatabase(path string, mode DatabaseMode) (*Database, Status) {

	var c_path *C.char = C.CString(path)
	defer C.free(unsafe.Pointer(c_path))

	if c_path == nil {
		return nil, STATUS_OUT_OF_MEMORY
	}

	self := &Database{db: nil}
	st := Status(C.notmuch_database_open(c_path, C.notmuch_database_mode_t(mode), &self.db))
	if st != STATUS_SUCCESS {
		return nil, st
	}
	return self, st
}

func (self *Database) Close() {
	C.notmuch_database_destroy(self.db)
}

// Return the database path of the given database.
func (self *Database) GetPath() string {

	/* The return value is a string owned by notmuch so should not be
	 * modified nor freed by the caller. */
	var p *C.char = C.notmuch_database_get_path(self.db)
	if p != nil {
		s := C.GoString(p)
		return s
	}
	return ""
}

// Return the database format version of the given database.
func (self *Database) GetVersion() uint {
	return uint(C.notmuch_database_get_version(self.db))
}

// Does this database need to be upgraded before writing to it?
func (self *Database) NeedsUpgrade() bool {
	do_upgrade := C.notmuch_database_needs_upgrade(self.db)
	if do_upgrade == 0 {
		return false
	}
	return true
}

// TODO: notmuch_database_upgrade

// Retrieve a directory object from the database for 'path'.
func (self *Database) GetDirectory(path string) (*Directory, Status) {
	var c_path *C.char = C.CString(path)
	defer C.free(unsafe.Pointer(c_path))

	if c_path == nil {
		return nil, STATUS_OUT_OF_MEMORY
	}

	var c_dir *C.notmuch_directory_t
	st := Status(C.notmuch_database_get_directory(self.db, c_path, &c_dir))
	if st != STATUS_SUCCESS || c_dir == nil {
		return nil, st
	}
	return &Directory{dir: c_dir}, st
}

// Add a new message to the given notmuch database.
//
// Here,'filename' should be a path relative to the path of
// 'database' (see notmuch_database_get_path), or else should be an
// absolute filename with initial components that match the path of
// 'database'.
//
// The file should be a single mail message (not a multi-message mbox)
// that is expected to remain at its current location, (since the
// notmuch database will reference the filename, and will not copy the
// entire contents of the file.)
//
// Return value:
//
// NOTMUCH_STATUS_SUCCESS: Message successfully added to database.
//
// NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred,
// message not added.
//
// NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID: Message has the same message
// ID as another message already in the database. The new
// filename was successfully added to the message in the database
// (if not already present).
//
// NOTMUCH_STATUS_FILE_ERROR: an error occurred trying to open the
// file, (such as permission denied, or file not found,
// etc.). Nothing added to the database.
//
// NOTMUCH_STATUS_FILE_NOT_EMAIL: the contents of filename don't look
// like an email message. Nothing added to the database.
//
// NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
// mode so no message can be added.
func (self *Database) AddMessage(fname string) (*Message, Status) {
	var c_fname *C.char = C.CString(fname)
	defer C.free(unsafe.Pointer(c_fname))

	if c_fname == nil {
		return nil, STATUS_OUT_OF_MEMORY
	}

	var c_msg *C.notmuch_message_t = new(C.notmuch_message_t)
	st := Status(C.notmuch_database_add_message(self.db, c_fname, &c_msg))

	return &Message{message: c_msg}, st
}

// Remove a message from the given notmuch database.
//
// Note that only this particular filename association is removed from
// the database. If the same message (as determined by the message ID)
// is still available via other filenames, then the message will
// persist in the database for those filenames. When the last filename
// is removed for a particular message, the database content for that
// message will be entirely removed.
//
// Return value:
//
// NOTMUCH_STATUS_SUCCESS: The last filename was removed and the
// message was removed from the database.
//
// NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred,
// message not removed.
//
// NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID: This filename was removed but
// the message persists in the database with at least one other
// filename.
//
// NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
// mode so no message can be removed.
func (self *Database) RemoveMessage(fname string) Status {

	var c_fname *C.char = C.CString(fname)
	defer C.free(unsafe.Pointer(c_fname))

	if c_fname == nil {
		return STATUS_OUT_OF_MEMORY
	}

	st := C.notmuch_database_remove_message(self.db, c_fname)
	return Status(st)
}

// Find a message with the given message_id. The caller should call
// Destroy() when done with the message.
func (self *Database) FindMessage(message_id string) (*Message, Status) {

	var c_msg_id *C.char = C.CString(message_id)
	defer C.free(unsafe.Pointer(c_msg_id))

	if c_msg_id == nil {
		return nil, STATUS_OUT_OF_MEMORY
	}

	msg := &Message{message: nil}
	st := Status(C.notmuch_database_find_message(self.db, c_msg_id, &msg.message))
	if st != STATUS_SUCCESS {
		return nil, st
	}
	return msg, st
}

// Return a list of all tags found in the database.
func (self *Database) GetAllTags() *Tags {
	tags := C.notmuch_database_get_all_tags(self.db)
	if tags == nil {
		return nil
	}
	return &Tags{tags: tags}
}

// Create a new query for Database. User should call Destroy() when
// finished with this query.
func (self *Database) CreateQuery(query string) *Query {

	var c_query *C.char = C.CString(query)
	defer C.free(unsafe.Pointer(c_query))

	if c_query == nil {
		return nil
	}

	q := C.notmuch_query_create(self.db, c_query)
	if q == nil {
		return nil
	}
	return &Query{query: q}
}

// Sort values for notmuch_query_set_sort
type Sort C.notmuch_sort_t

const (
	SORT_OLDEST_FIRST Sort = 0
	SORT_NEWEST_FIRST
	SORT_MESSAGE_ID
	SORT_UNSORTED
)

func (self *Query) String() string {
	// FIXME: do we own 'q' or not ?
	q := C.notmuch_query_get_query_string(self.query)
	//defer C.free(unsafe.Pointer(q))

	if q != nil {
		s := C.GoString(q)
		return s
	}

	return ""
}

func (self *Query) SetSort(sort Sort) {
	C.notmuch_query_set_sort(self.query, C.notmuch_sort_t(sort))
}

func (self *Query) GetSort() Sort {
	return Sort(C.notmuch_query_get_sort(self.query))
}

// Execute a query for threads, returning a *Threads object
// which can be used to iterate over the results like so:
//
// 	q := db.CreateQuery("*")
// 	defer q.Destroy()
//
// 	ts := q.SearchThreads()
// 	for ; ts.Valid(); ts.MoveToNext() {
// 		t := ts.Get()
// 		// do something here
// 	}
//
// The returned object is owned by the query and as such, will only be valid
// until the query is destroyed.
func (self *Query) SearchThreads() *Threads {
	threads := C.notmuch_query_search_threads(self.query)
	if threads == nil {
		return nil
	}
	return &Threads{threads: threads}
}

// Execute a query for messages, returning a *Messages object
// which can be used to iterate over the results. See SearchThreads().
func (self *Query) SearchMessages() *Messages {
	msgs := C.notmuch_query_search_messages(self.query)
	if msgs == nil {
		return nil
	}
	return &Messages{messages: msgs}
}

// Destroy a notmuch_query_t along with any associated resources.
func (self *Query) Destroy() {
	if self.query != nil {
		C.notmuch_query_destroy(self.query)
	}
}

// Return an estimate of the number of messages matching a search
//
// This function performs a search and returns Xapian's best
// guess as to number of matching messages.
func (self *Query) CountMessages() uint {
	return uint(C.notmuch_query_count_messages(self.query))
}

// TODO: wrap threads and thread

func (self *Threads) Valid() bool {
	if self.threads == nil {
		return false
	}
	valid := C.notmuch_threads_valid(self.threads)
	if valid == 0 {
		return false
	}
	return true
}

func (self *Threads) Destroy() {
	if self.threads != nil {
		C.notmuch_threads_destroy(self.threads)
	}
}

func (self *Messages) Valid() bool {
	if self.messages == nil {
		return false
	}
	valid := C.notmuch_messages_valid(self.messages)
	if valid == 0 {
		return false
	}
	return true
}

func (self *Messages) Get() *Message {
	if self.messages == nil {
		return nil
	}
	msg := C.notmuch_messages_get(self.messages)
	if msg == nil {
		return nil
	}
	return &Message{message: msg}
}

func (self *Messages) MoveToNext() {
	if self.messages == nil {
		return
	}
	C.notmuch_messages_move_to_next(self.messages)
}

func (self *Messages) Destroy() {
	if self.messages != nil {
		C.notmuch_messages_destroy(self.messages)
	}
}

// Return a list of tags from all messages.
//
// The resulting list is guaranteed not to contain duplicated tags.
//
// WARNING: You can no longer iterate over messages after calling this
// function, because the iterator will point at the end of the list.
// We do not have a function to reset the iterator yet and the only
// way how you can iterate over the list again is to recreate the
// message list.
func (self *Messages) CollectTags() *Tags {
	if self.messages == nil {
		return nil
	}
	tags := C.notmuch_messages_collect_tags(self.messages)
	if tags == nil {
		return nil
	}
	return &Tags{tags: tags}
}

// Get the message ID of 'message'.
//
// The returned string belongs to 'message' and as such, should not be
// modified by the caller and will only be valid for as long as the
// message is valid, (which is until the query from which it derived
// is destroyed).
//
// Notmuch ensures that every message has a unique message ID,
// (Notmuch will generate an ID for a message if the original file
// does not contain one).
func (self *Message) GetMessageId() string {

	if self.message == nil {
		return ""
	}
	id := C.notmuch_message_get_message_id(self.message)
	// we dont own id
	// defer C.free(unsafe.Pointer(id))
	if id == nil {
		return ""
	}
	return C.GoString(id)
}

// Get the thread ID of 'message'. See GetMessageId().
func (self *Message) GetThreadId() string {

	if self.message == nil {
		return ""
	}
	id := C.notmuch_message_get_thread_id(self.message)
	// we dont own id
	// defer C.free(unsafe.Pointer(id))

	if id == nil {
		return ""
	}

	return C.GoString(id)
}

// Returns an *Messages object for all replies to the given message.
// Note: This call only makes sense if the message was obtained from a
// query for threads.
func (self *Message) GetReplies() *Messages {
	if self.message == nil {
		return nil
	}
	msgs := C.notmuch_message_get_replies(self.message)
	if msgs == nil {
		return nil
	}
	return &Messages{messages: msgs}
}

// Return the filename for the email corresponding to the message.
// The returned filename is an absolute filename, (the initial
// component will match notmuch_database_get_path() ).
func (self *Message) GetFileName() string {
	if self.message == nil {
		return ""
	}
	fname := C.notmuch_message_get_filename(self.message)
	// we dont own fname
	// defer C.free(unsafe.Pointer(fname))

	if fname == nil {
		return ""
	}

	return C.GoString(fname)
}

type Flag C.notmuch_message_flag_t

const (
	MESSAGE_FLAG_MATCH Flag = 0
)

func (self *Message) GetFlag(flag Flag) bool {
	if self.message == nil {
		return false
	}
	v := C.notmuch_message_get_flag(self.message, C.notmuch_message_flag_t(flag))
	if v == 0 {
		return false
	}
	return true
}

func (self *Message) SetFlag(flag Flag, value bool) {
	if self.message == nil {
		return
	}
	var v C.notmuch_bool_t = 0
	if value {
		v = 1
	}
	C.notmuch_message_set_flag(self.message, C.notmuch_message_flag_t(flag), v)
}

// TODO: wrap notmuch_message_get_date

// Get the value of the specified header from the message. The value
// will be read from the actual message file, not from the notmuch
// database. The header name is case insensitive.
//
// Returns an empty string ("") if the message does not contain a
// header line matching 'header' or an error occured.
func (self *Message) GetHeader(header string) string {
	if self.message == nil {
		return ""
	}

	var c_header *C.char = C.CString(header)
	defer C.free(unsafe.Pointer(c_header))

	/* we dont own value */
	value := C.notmuch_message_get_header(self.message, c_header)
	if value == nil {
		return ""
	}

	return C.GoString(value)
}

// Get the tags for 'message', returning a *Tags object which
// can be used to iterate over all tags. See SearchThreads().
func (self *Message) GetTags() *Tags {
	if self.message == nil {
		return nil
	}
	tags := C.notmuch_message_get_tags(self.message)
	if tags == nil {
		return nil
	}
	return &Tags{tags: tags}
}

/* The longest possible tag value. */
const TAG_MAX = 200

// Add a tag to the given message.
//
// Return value:
//
// NOTMUCH_STATUS_SUCCESS: Tag successfully added to message
//
// NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
//
// NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
// (exceeds NOTMUCH_TAG_MAX)
//
// NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
// mode so message cannot be modified.
func (self *Message) AddTag(tag string) Status {
	if self.message == nil {
		return STATUS_NULL_POINTER
	}
	c_tag := C.CString(tag)
	defer C.free(unsafe.Pointer(c_tag))

	return Status(C.notmuch_message_add_tag(self.message, c_tag))
}

func (self *Message) RemoveTag(tag string) Status {
	if self.message == nil {
		return STATUS_NULL_POINTER
	}
	c_tag := C.CString(tag)
	defer C.free(unsafe.Pointer(c_tag))

	return Status(C.notmuch_message_remove_tag(self.message, c_tag))
}

func (self *Message) RemoveAllTags() Status {
	if self.message == nil {
		return STATUS_NULL_POINTER
	}
	return Status(C.notmuch_message_remove_all_tags(self.message))
}

// Freeze the current state of the message within the database.
//
// This means that changes to the message state will not be committed
// to the database until the message is thawed with Thaw().
//
// Multiple calls to freeze/thaw are valid and these calls will
// "stack". That is there must be as many calls to thaw as to freeze
// before a message is actually thawed.
//
// The ability to do freeze/thaw allows for safe transactions to
// change tag values. For example, explicitly setting a message to
// have a given set of tags might look like this:
//
//    notmuch_message_freeze (message);
//
//    notmuch_message_remove_all_tags (message);
//
//    for (i = 0; i < NUM_TAGS; i++)
//        notmuch_message_add_tag (message, tags[i]);
//
//    notmuch_message_thaw (message);
//
// With freeze/thaw used like this, the message in the database is
// guaranteed to have either the full set of original tag values, or
// the full set of new tag values, but nothing in between.
//
// Imagine the example above without freeze/thaw and the operation
// somehow getting interrupted. This could result in the message being
// left with no tags if the interruption happened after
// notmuch_message_remove_all_tags but before notmuch_message_add_tag.
//
// Return value:
//
// NOTMUCH_STATUS_SUCCESS: Message successfully frozen.
//
// NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
// mode so message cannot be modified.
///
func (self *Message) Freeze() Status {
	if self.message == nil {
		return STATUS_NULL_POINTER
	}
	return Status(C.notmuch_message_freeze(self.message))
}

// Thaw the current 'message', synchronizing any changes that may have
// occurred while 'message' was frozen into the notmuch database.
func (self *Message) Thaw() Status {
	if self.message == nil {
		return STATUS_NULL_POINTER
	}

	return Status(C.notmuch_message_thaw(self.message))
}

// Destroy a notmuch_message_t object.
//
// It can be useful to call this function in the case of a single
// query object with many messages in the result, (such as iterating
// over the entire database). Otherwise, it's fine to never call this
// function and there will still be no memory leaks. (The memory from
// the messages get reclaimed when the containing query is destroyed.)
func (self *Message) Destroy() {
	if self.message == nil {
		return
	}
	C.notmuch_message_destroy(self.message)
}

func (self *Tags) Valid() bool {
	if self.tags == nil {
		return false
	}
	v := C.notmuch_tags_valid(self.tags)
	if v == 0 {
		return false
	}
	return true
}

func (self *Tags) Get() string {
	if self.tags == nil {
		return ""
	}
	s := C.notmuch_tags_get(self.tags)
	// we dont own 's'

	return C.GoString(s)
}

func (self *Tags) String() string {
	return self.Get()
}

func (self *Tags) MoveToNext() {
	if self.tags == nil {
		return
	}
	C.notmuch_tags_move_to_next(self.tags)
}

func (self *Tags) Destroy() {
	if self.tags == nil {
		return
	}
	C.notmuch_tags_destroy(self.tags)
}

// TODO: wrap notmuch_directory_<fct>

// Destroy a notmuch_directory_t object.
func (self *Directory) Destroy() {
	if self.dir == nil {
		return
	}
	C.notmuch_directory_destroy(self.dir)
}

// TODO: wrap notmuch_filenames_<fct>

func (self *Filenames) Destroy() {
	if self.fnames == nil {
		return
	}
	C.notmuch_filenames_destroy(self.fnames)
}

/* EOF */