/* Copyright (c) 2004-2009 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "array.h"
#include "buffer.h"
#include "seq-range-array.h"
#include "mail-index-private.h"
#include "mail-index-view-private.h"
#include "mail-index-transaction-private.h"

struct mail_index_view_transaction {
	struct mail_index_view view;
	struct mail_index_view_vfuncs *super;
	struct mail_index_transaction *t;

	struct mail_index_map *lookup_map;
	struct mail_index_header hdr;

	buffer_t *lookup_return_data;
	uint32_t lookup_prev_seq;

	unsigned int recs_count;
	struct mail_index_record *recs;
};

static void tview_close(struct mail_index_view *view)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;
	struct mail_index_transaction *t = tview->t;

	if (tview->lookup_map != NULL)
		mail_index_unmap(&tview->lookup_map);
	if (tview->lookup_return_data != NULL)
		buffer_free(&tview->lookup_return_data);
	i_free(tview->recs);

	tview->super->close(view);
	mail_index_transaction_unref(&t);
}

static uint32_t tview_get_message_count(struct mail_index_view *view)
{
	struct mail_index_view_transaction *tview =
                (struct mail_index_view_transaction *)view;

	return view->map->hdr.messages_count +
		(tview->t->last_new_seq == 0 ? 0 :
		 tview->t->last_new_seq - tview->t->first_new_seq + 1);
}

static const struct mail_index_header *
tview_get_header(struct mail_index_view *view)
{
	struct mail_index_view_transaction *tview =
                (struct mail_index_view_transaction *)view;
	const struct mail_index_header *hdr;
	uint32_t next_uid;

	/* FIXME: header counters may not be correct */
	hdr = tview->super->get_header(view);

	next_uid = mail_index_transaction_get_next_uid(tview->t);
	if (next_uid != hdr->next_uid) {
		tview->hdr = *hdr;
		tview->hdr.next_uid = next_uid;
		hdr = &tview->hdr;
	}
	return hdr;
}

static const struct mail_index_record *
tview_apply_flag_updates(struct mail_index_view_transaction *tview,
			 const struct mail_index_record *rec, uint32_t seq)
{
	struct mail_index_transaction *t = tview->t;
	const struct mail_transaction_flag_update *updates;
	unsigned int idx, count;

	/* see if there are any flag updates */
	if (seq < t->min_flagupdate_seq || seq > t->max_flagupdate_seq ||
	    !array_is_created(&t->updates))
		return rec;

	updates = array_get(&t->updates, &count);
	idx = mail_index_transaction_get_flag_update_pos(t, 0, count, seq);
	if (seq < updates[idx].uid1 || seq > updates[idx].uid2)
		return rec;

	/* yes, we have flag updates. since we can't modify rec directly and
	   we want to be able to handle multiple mail_index_lookup() calls
	   without the second one overriding the first one's data, we'll
	   create a records array and return data from there */
	if (tview->recs == NULL) {
		tview->recs_count = t->first_new_seq;
		tview->recs = i_new(struct mail_index_record,
				    tview->recs_count);
	}
	i_assert(tview->recs_count == t->first_new_seq);
	i_assert(seq > 0 && seq <= tview->recs_count);

	tview->recs[seq-1] = *rec;
	tview->recs[seq-1].flags |= updates[idx].add_flags;
	tview->recs[seq-1].flags &= ~updates[idx].remove_flags;
	return &tview->recs[seq-1];
}

static const struct mail_index_record *
tview_lookup_full(struct mail_index_view *view, uint32_t seq,
		  struct mail_index_map **map_r, bool *expunged_r)
{
	struct mail_index_view_transaction *tview =
                (struct mail_index_view_transaction *)view;
	const struct mail_index_record *rec;

	if (seq >= tview->t->first_new_seq) {
		/* FIXME: is this right to return index map..?
		   it's not there yet. */
		*map_r = view->index->map;
		*expunged_r = FALSE;
		return mail_index_transaction_lookup(tview->t, seq);
	}

	rec = tview->super->lookup_full(view, seq, map_r, expunged_r);
	rec = tview_apply_flag_updates(tview, rec, seq);

	if (array_is_created(&tview->t->expunges) &&
	    seq_range_exists(&tview->t->expunges, seq))
		*expunged_r = TRUE;
	return rec;
}

static void
tview_lookup_uid(struct mail_index_view *view, uint32_t seq, uint32_t *uid_r)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;

	if (seq >= tview->t->first_new_seq)
		*uid_r = mail_index_transaction_lookup(tview->t, seq)->uid;
	else
		tview->super->lookup_uid(view, seq, uid_r);
}

static void tview_lookup_seq_range(struct mail_index_view *view,
				   uint32_t first_uid, uint32_t last_uid,
				   uint32_t *first_seq_r, uint32_t *last_seq_r)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;
	const struct mail_index_record *rec;
	uint32_t seq;

	if (!tview->t->reset) {
		tview->super->lookup_seq_range(view, first_uid, last_uid,
					       first_seq_r, last_seq_r);
	} else {
		/* index is being reset. we never want to return old
		   sequences. */
		*first_seq_r = *last_seq_r = 0;
	}
	if (tview->t->last_new_seq == 0) {
		/* no new messages, the results are final. */
		return;
	}

	rec = mail_index_transaction_lookup(tview->t, tview->t->first_new_seq);
	if (rec->uid == 0) {
		/* new messages don't have UIDs */
		return;
	}
	if (last_uid < rec->uid) {
		/* all wanted messages were existing */
		return;
	}

	/* at least some of the wanted messages are newly created */
	if (*first_seq_r == 0) {
		seq = tview->t->first_new_seq;
		for (; seq <= tview->t->last_new_seq; seq++) {
			rec = mail_index_transaction_lookup(tview->t, seq);
			if (first_uid <= rec->uid)
				break;
		}
		if (seq > tview->t->last_new_seq) {
			/* no messages in range */
			return;
		}
		*first_seq_r = seq;
	}

	seq = tview->t->last_new_seq;
	for (; seq >= tview->t->first_new_seq; seq--) {
		rec = mail_index_transaction_lookup(tview->t, seq);
		if (rec->uid <= last_uid) {
			*last_seq_r = seq;
			break;
		}
	}
	i_assert(seq >= tview->t->first_new_seq);
}

static void tview_lookup_first(struct mail_index_view *view,
			       enum mail_flags flags, uint8_t flags_mask,
			       uint32_t *seq_r)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;
	const struct mail_index_record *rec;
	unsigned int append_count;
	uint32_t seq, message_count;

	if (!tview->t->reset) {
		tview->super->lookup_first(view, flags, flags_mask, seq_r);
		if (*seq_r != 0)
			return;
	} else {
		*seq_r = 0;
	}

	rec = array_get(&tview->t->appends, &append_count);
	seq = tview->t->first_new_seq;
	message_count = tview->t->last_new_seq;
	i_assert(append_count == message_count - seq + 1);

	for (; seq <= message_count; seq++, rec++) {
		if ((rec->flags & flags_mask) == (uint8_t)flags) {
			*seq_r = seq;
			break;
		}
	}
}

static void keyword_index_add(ARRAY_TYPE(keyword_indexes) *keywords,
			      unsigned int idx)
{
	const unsigned int *indexes;
	unsigned int i, count;

	indexes = array_get(keywords, &count);
	for (i = 0; i < count; i++) {
		if (indexes[i] == idx)
			return;
	}
	array_append(keywords, &idx, 1);
}

static void keyword_index_remove(ARRAY_TYPE(keyword_indexes) *keywords,
				 unsigned int idx)
{
	const unsigned int *indexes;
	unsigned int i, count;

	indexes = array_get(keywords, &count);
	for (i = 0; i < count; i++) {
		if (indexes[i] == idx) {
			array_delete(keywords, i, 1);
			break;
		}
	}
}

static void tview_lookup_keywords(struct mail_index_view *view, uint32_t seq,
				  ARRAY_TYPE(keyword_indexes) *keyword_idx)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;
	struct mail_index_transaction *t = tview->t;
	const struct mail_index_transaction_keyword_update *updates;
	unsigned int i, count;

	tview->super->lookup_keywords(view, seq, keyword_idx);

	if (seq < t->min_flagupdate_seq || seq > t->max_flagupdate_seq) {
		/* no keyword updates for this sequence */
		return;
	}

	/* apply any keyword updates in this transaction */
	if (array_is_created(&t->keyword_resets)) {
		if (seq_range_exists(&t->keyword_resets, seq))
			array_clear(keyword_idx);
	}

	if (array_is_created(&t->keyword_updates))
		updates = array_get(&t->keyword_updates, &count);
	else {
		updates = NULL;
		count = 0;
	}
	for (i = 0; i < count; i++) {
		if (array_is_created(&updates[i].add_seq) &&
		    seq_range_exists(&updates[i].add_seq, seq))
			keyword_index_add(keyword_idx, i);
		else if (array_is_created(&updates[i].remove_seq) &&
			 seq_range_exists(&updates[i].remove_seq, seq))
			keyword_index_remove(keyword_idx, i);
	}
}

static struct mail_index_map *
tview_get_lookup_map(struct mail_index_view_transaction *tview)
{
	if (tview->lookup_map == NULL) {
		tview->lookup_map =
			mail_index_map_clone(tview->view.index->map);
	}
	return tview->lookup_map;
}

static const void *
tview_return_updated_ext(struct mail_index_view_transaction *tview,
			 uint32_t seq, const void *data, uint32_t ext_id)
{
	const struct mail_index_ext *ext;
	const struct mail_index_registered_ext *rext;
	const struct mail_transaction_ext_intro *intro;
	unsigned int record_align, record_size;
	uint32_t ext_idx;
	size_t pos;

	/* data begins with a 32bit sequence, followed by the actual
	   extension data */
	data = CONST_PTR_OFFSET(data, sizeof(uint32_t));

	if (!mail_index_map_get_ext_idx(tview->lookup_map, ext_id, &ext_idx)) {
		/* we're adding the extension now. */
		rext = array_idx(&tview->view.index->extensions, ext_id);
		record_align = rext->record_align;
		record_size = rext->record_size;
	} else {
		ext = array_idx(&tview->lookup_map->extensions, ext_idx);
		record_align = ext->record_align;
		record_size = ext->record_size;
	}

	/* see if the extension has been resized within this transaction */
	if (array_is_created(&tview->t->ext_resizes) &&
	    ext_id < array_count(&tview->t->ext_resizes)) {
		intro = array_idx(&tview->t->ext_resizes, ext_id);
		if (intro[ext_id].name_size != 0) {
			record_align = intro->record_align;
			record_size = intro->record_size;
		}
	}

	if (record_align <= sizeof(uint32_t)) {
		/* data is 32bit aligned already */
		return data;
	} else {
		/* assume we want 64bit alignment - copy the data to
		   temporary buffer and return it */
		if (tview->lookup_return_data == NULL) {
			tview->lookup_return_data =
				buffer_create_dynamic(default_pool,
						      record_size + 64);
		} else if (seq != tview->lookup_prev_seq) {
			/* clear the buffer between lookups for different
			   messages */
			buffer_set_used_size(tview->lookup_return_data, 0);
		}
		tview->lookup_prev_seq = seq;
		pos = tview->lookup_return_data->used;
		buffer_append(tview->lookup_return_data, data, record_size);
		return CONST_PTR_OFFSET(tview->lookup_return_data->data, pos);
	}
}

static void
tview_lookup_ext_full(struct mail_index_view *view, uint32_t seq,
		      uint32_t ext_id, struct mail_index_map **map_r,
		      const void **data_r, bool *expunged_r)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;
	const ARRAY_TYPE(seq_array) *ext_buf;
	const void *data;
	unsigned int idx;

	i_assert(ext_id < array_count(&view->index->extensions));

	*expunged_r = FALSE;

	if (array_is_created(&tview->t->ext_rec_updates) &&
	    ext_id < array_count(&tview->t->ext_rec_updates)) {
		/* there are some ext updates in transaction.
		   see if there's any for this sequence. */
		ext_buf = array_idx(&tview->t->ext_rec_updates, ext_id);
		if (array_is_created(ext_buf) &&
		    mail_index_seq_array_lookup(ext_buf, seq, &idx)) {
			data = array_idx(ext_buf, idx);
			*map_r = tview_get_lookup_map(tview);
			*data_r = tview_return_updated_ext(tview, seq, data,
							   ext_id);
			return;
		}
	}

	/* not updated, return the existing value */
	if (seq < tview->t->first_new_seq) {
		tview->super->lookup_ext_full(view, seq, ext_id,
					      map_r, data_r, expunged_r);
	} else {
		*map_r = view->index->map;
		*data_r = NULL;
	}
}

static void tview_get_header_ext(struct mail_index_view *view,
				 struct mail_index_map *map, uint32_t ext_id,
				 const void **data_r, size_t *data_size_r)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;

	/* FIXME: check updates */
	tview->super->get_header_ext(view, map, ext_id, data_r, data_size_r);
}

static bool tview_ext_get_reset_id(struct mail_index_view *view,
				   struct mail_index_map *map,
				   uint32_t ext_id, uint32_t *reset_id_r)
{
	struct mail_index_view_transaction *tview =
		(struct mail_index_view_transaction *)view;
	const uint32_t *reset_id_p;

	if (array_is_created(&tview->t->ext_reset_ids) &&
	    ext_id < array_count(&tview->t->ext_reset_ids) &&
	    map == tview->lookup_map) {
		reset_id_p = array_idx(&tview->t->ext_reset_ids, ext_id);
		*reset_id_r = *reset_id_p;
		return TRUE;
	}

	return tview->super->ext_get_reset_id(view, map, ext_id, reset_id_r);
}

static struct mail_index_view_vfuncs trans_view_vfuncs = {
	tview_close,
        tview_get_message_count,
	tview_get_header,
	tview_lookup_full,
	tview_lookup_uid,
	tview_lookup_seq_range,
	tview_lookup_first,
	tview_lookup_keywords,
	tview_lookup_ext_full,
	tview_get_header_ext,
	tview_ext_get_reset_id
};

struct mail_index_view *
mail_index_transaction_open_updated_view(struct mail_index_transaction *t)
{
	struct mail_index_view_transaction *tview;

	if (t->view->syncing) {
		/* transaction view is being synced. while it's done, it's not
		   possible to add new messages, but the view itself might
		   change. so we can't make a copy of the view. */
		mail_index_view_ref(t->view);
		return t->view;
	}

	tview = i_new(struct mail_index_view_transaction, 1);
	mail_index_view_clone(&tview->view, t->view);
	tview->view.v = trans_view_vfuncs;
	tview->super = &t->view->v;
	tview->t = t;

	mail_index_transaction_ref(t);
	return &tview->view;
}