/* Copyright (C) 2002 Timo Sirainen */

#include "lib.h"
#include "iobuffer.h"
#include "ioloop.h"
#include "rfc822-date.h"
#include "rfc822-tokenize.h"
#include "message-parser.h"
#include "message-size.h"
#include "imap-envelope.h"
#include "imap-bodystructure.h"
#include "mail-index.h"
#include "mail-index-data.h"
#include "mail-index-util.h"

struct _MailIndexUpdate {
	Pool pool;

	MailIndex *index;
	MailIndexRecord *rec;

	unsigned int updated_fields;
	char *fields[FIELD_TYPE_MAX_BITS];
	unsigned int field_sizes[FIELD_TYPE_MAX_BITS];
	unsigned int field_extra_sizes[FIELD_TYPE_MAX_BITS];
};

MailIndexUpdate *mail_index_update_begin(MailIndex *index, MailIndexRecord *rec)
{
	Pool pool;
	MailIndexUpdate *update;

	i_assert(index->lock_type == MAIL_LOCK_EXCLUSIVE);

	pool = pool_create("MailIndexUpdate", 1024, FALSE);

	update = p_new(pool, MailIndexUpdate, 1);
	update->pool = pool;
	update->index = index;
	update->rec = rec;
	return update;
}

static int mail_field_get_index(MailField field)
{
	unsigned int i, mask;

	for (i = 0, mask = 1; i < FIELD_TYPE_MAX_BITS; i++, mask <<= 1) {
		if (field == mask)
			return i;
	}

	return -1;
}

static int have_new_fields(MailIndexUpdate *update)
{
	MailField field;

	if (update->rec->cached_fields == 0) {
		/* new record */
		return TRUE;
	}

	for (field = 1; field != FIELD_TYPE_LAST; field <<= 1) {
		if ((update->updated_fields & field) &&
		    (update->rec->cached_fields & field) == 0)
			return TRUE;
	}

	return FALSE;
}

static int have_too_large_fields(MailIndexUpdate *update)
{
	MailIndexDataRecord *rec;
	unsigned int size_left;
	int index;

	size_left = update->rec->data_size;

	/* start from the first data field - it's required to exist */
	rec = mail_index_data_lookup(update->index->data, update->rec, 1);
	while (rec != NULL) {
		if (rec->full_field_size > size_left) {
			/* corrupted */
			update->index->header->flags |= MAIL_INDEX_FLAG_REBUILD;
			return TRUE;
		}
		size_left -= rec->full_field_size;

		if (rec->field & update->updated_fields) {
			/* field was changed */
			index = mail_field_get_index(rec->field);
			i_assert(index >= 0);

			if (update->field_sizes[index] >= rec->full_field_size)
				return TRUE;
		}
		rec = mail_index_data_next(update->index->data,
					   update->rec, rec);
	}

	return FALSE;
}

/* Append all the data at the end of the data file and update 
   the index's data position */
static int update_by_append(MailIndexUpdate *update)
{
        MailIndexDataRecord *rec, *destrec;
	MailField field;
	uoff_t fpos;
	void *mem;
	const void *src;
	unsigned int max_size, pos, src_size;
	int i;

	/* allocate the old size + also the new size of all changed or added
	   fields. this is more than required, but it's much easier than
	   calculating the exact size.

	   If this calculation overflows (no matter what value), it doesn't
	   really matter as it's later checked anyway. */
	max_size = update->rec->data_size;
	for (i = 0; i < FIELD_TYPE_MAX_BITS; i++) {
		max_size += SIZEOF_MAIL_INDEX_DATA +
			update->field_sizes[i] +
			update->field_extra_sizes[i] + MEM_ALIGN_SIZE-1;
	}

	if (max_size > INT_MAX) {
		/* rec->data_size most likely corrupted */
		index_set_error(update->index, "Error in index file %s: "
				"data_size points outside file",
				update->index->filepath);
		update->index->header->flags |= MAIL_INDEX_FLAG_REBUILD;
		return FALSE;
	}

	/* allocate two extra records to avoid overflows in case of bad
	   rec->full_field_size which itself fits into max_size, but
	   either the record part would make it point ouside allocate memory,
	   or the next field's record would do that */
	mem = p_malloc(update->pool, max_size + sizeof(MailIndexDataRecord)*2);
	pos = 0;

	rec = mail_index_data_lookup(update->index->data, update->rec, 1);
	for (i = 0, field = 1; field != FIELD_TYPE_LAST; i++, field <<= 1) {
		destrec = (MailIndexDataRecord *) ((char *) mem + pos);

		if (update->fields[i] != NULL) {
			/* value was modified - use it */
			destrec->full_field_size = update->field_sizes[i] +
				update->field_extra_sizes[i];
			src = update->fields[i];
			src_size = update->field_sizes[i];
		} else if (rec != NULL) {
			/* use the old value */
			destrec->full_field_size = rec->full_field_size;
			src = rec->data;
			src_size = rec->full_field_size;
		} else {
			/* the field doesn't exist, jump to next */
			continue;
		}

		if (src_size > max_size || max_size - src_size < pos) {
			/* corrupted data file - old value had a field
			   larger than expected */
			index_set_error(update->index,
					"Error in index file %s: "
					"full_field_size points outside "
					"data_size", update->index->filepath);
			update->index->header->flags |= MAIL_INDEX_FLAG_REBUILD;
			return FALSE;
		}
		memcpy(destrec->data, src, src_size);

		/* memory alignment fix */
		destrec->full_field_size = MEM_ALIGN(destrec->full_field_size);

		destrec->field = field;
		pos += DATA_RECORD_SIZE(destrec);

		if (rec != NULL && rec->field == field) {
			rec = mail_index_data_next(update->index->data,
						   update->rec, rec);
		}
	}

	i_assert(pos <= max_size);

	/* append the data at the end of the data file */
	fpos = mail_index_data_append(update->index->data, mem, pos);
	if (fpos == 0)
		return FALSE;

	/* update index file position - it's mmap()ed so it'll be writte
	   into disk when index is unlocked. */
	update->rec->data_position = fpos;
	update->rec->data_size = pos;
	return TRUE;
}

/* Replace the modified fields in the file - assumes there's enough
   space to do it */
static void update_by_replace(MailIndexUpdate *update)
{
	MailIndexDataRecord *rec;
	int index;

	/* start from the first data field - it's required to exist */
	rec = mail_index_data_lookup(update->index->data, update->rec, 1);
	while (rec != NULL) {
		if (rec->field & update->updated_fields) {
			/* field was changed */
			index = mail_field_get_index(rec->field);
			i_assert(index >= 0);

			i_assert(update->field_sizes[index] <=
				 rec->full_field_size);

			memcpy(rec->data, update->fields[index],
			       update->field_sizes[index]);
		}
		rec = mail_index_data_next(update->index->data,
					   update->rec, rec);
	}
}

int mail_index_update_end(MailIndexUpdate *update)
{
	int failed;

	i_assert(update->index->lock_type == MAIL_LOCK_EXCLUSIVE);

	/* if any of the fields were newly added, or have grown larger
	   than their old max. size, we need to move the record to end
	   of file. */
	if (have_new_fields(update) || have_too_large_fields(update))
		failed = !update_by_append(update);
	else {
		update_by_replace(update);
		failed = FALSE;
	}

	if (!failed) {
		/* update cached fields mask */
		update->rec->cached_fields |= update->updated_fields;
	}

	pool_unref(update->pool);
	return !failed;
}

void mail_index_update_field(MailIndexUpdate *update, MailField field,
			     const char *value, unsigned int extra_space)
{
	unsigned int size;
	int index;

	index = mail_field_get_index(field);
	i_assert(index >= 0);

	size = strlen(value)+1;

	update->updated_fields |= field;
	update->field_sizes[index] = size;
	update->field_extra_sizes[index] = extra_space;
	update->fields[index] = p_malloc(update->pool, size);
	memcpy(update->fields[index], value, size);
}

static MailField mail_header_get_field(const char *str, unsigned int len)
{
	if (len == 7 && strncasecmp(str, "Subject", 7) == 0)
		return FIELD_TYPE_SUBJECT;
	if (len == 4 && strncasecmp(str, "From", 4) == 0)
		return FIELD_TYPE_FROM;
	if (len == 2 && strncasecmp(str, "To", 2) == 0)
		return FIELD_TYPE_TO;
	if (len == 2 && strncasecmp(str, "Cc", 2) == 0)
		return FIELD_TYPE_CC;
	if (len == 3 && strncasecmp(str, "Bcc", 3) == 0)
		return FIELD_TYPE_BCC;

	return 0;
}

static const char *field_get_value(const char *value, unsigned int len)
{
	char *ret, *p;
	unsigned int i;

	ret = t_malloc(len+1);

	/* compress the long headers (remove \r?\n before space or tab) */
	for (i = 0, p = ret; i < len; i++) {
		if (value[i] == '\r' && i+1 != len && value[i+1] == '\n')
			i++;

		if (value[i] == '\n') {
			i_assert(IS_LWSP(value[i+1]));
		} else {
			*p++ = value[i];
		}
	}
	*p = '\0';

	return ret;
}

typedef struct {
	MailIndexUpdate *update;
	Pool envelope_pool;
	MessagePartEnvelopeData *envelope;

	MessageHeaderFunc header_func;
	void *context;
} HeaderUpdateContext;

static void update_header_func(MessagePart *part,
			       const char *name, unsigned int name_len,
			       const char *value, unsigned int value_len,
			       void *context)
{
	HeaderUpdateContext *ctx = context;
	MailField field;
	const char *str;

	if (part != NULL && part->parent != NULL)
		return;

	if (ctx->header_func != NULL) {
		ctx->header_func(part, name, name_len,
				 value, value_len, ctx->context);
	}

	if (name_len == 4 && strncasecmp(name, "Date", 4) == 0) {
		/* date is stored into index record itself */
		str = field_get_value(value, value_len);
		if (!rfc822_parse_date(str, &ctx->update->rec->sent_date))
			ctx->update->rec->sent_date = ioloop_time;
		return;
	}

	/* see if we can do anything with this field */
	field = mail_header_get_field(name, name_len);
	if (field != 0) {
		/* do we want to store this? */
		if (ctx->update->index->header->cache_fields & field) {
			str = field_get_value(value, value_len);
			ctx->update->index->update_field(ctx->update,
							 field, str, 0);
		}
	}

	if (ctx->update->index->header->cache_fields & FIELD_TYPE_ENVELOPE) {
		if (ctx->envelope_pool == NULL) {
			ctx->envelope_pool =
				pool_create("index envelope", 2048, FALSE);
		}
		imap_envelope_parse_header(ctx->envelope_pool,
					   &ctx->envelope,
					   t_strndup(name, name_len),
					   value, value_len);
	}
}

void mail_index_update_headers(MailIndexUpdate *update, IOBuffer *inbuf,
                               MailField cache_fields,
			       MessageHeaderFunc header_func, void *context)
{
	HeaderUpdateContext ctx;
	MessagePart *part;
	MessageSize hdr_size, body_size;
	Pool pool;
	const char *value;

	ctx.update = update;
	ctx.envelope_pool = NULL;
	ctx.envelope = NULL;
	ctx.header_func = header_func;
	ctx.context = context;

	if (cache_fields == 0)
                cache_fields = update->index->header->cache_fields;

	if ((cache_fields & (FIELD_TYPE_BODY|FIELD_TYPE_BODYSTRUCTURE)) != 0) {
		/* for body / bodystructure, we need need to
		   fully parse the message */
		pool = pool_create("index message parser", 2048, FALSE);
		part = message_parse(pool, inbuf, update_header_func, &ctx);

		/* update our sizes */
		update->rec->header_size = part->header_size.physical_size;
		update->rec->body_size = part->body_size.physical_size;
		update->rec->full_virtual_size =
			part->header_size.virtual_size +
			part->body_size.virtual_size;

		if (cache_fields & FIELD_TYPE_BODY) {
			t_push();
			io_buffer_seek(inbuf, 0);
			value = imap_part_get_bodystructure(pool, &part,
							    inbuf, FALSE);
			update->index->update_field(update, FIELD_TYPE_BODY,
						    value, 0);
			t_pop();
		}

		if (cache_fields & FIELD_TYPE_BODYSTRUCTURE) {
			t_push();
			io_buffer_seek(inbuf, 0);
			value = imap_part_get_bodystructure(pool, &part,
							    inbuf, TRUE);
			update->index->update_field(update,
						    FIELD_TYPE_BODYSTRUCTURE,
						    value, 0);
			t_pop();
		}

		pool_unref(pool);
	} else {
		message_parse_header(NULL, inbuf, &hdr_size,
				     update_header_func, &ctx);

		update->rec->header_size = hdr_size.physical_size;
		update->rec->body_size = inbuf->size - inbuf->offset;

		if (update->rec->full_virtual_size == 0) {
			/* we need to calculate virtual size of the
			   body as well. message_parse_header() left the
			   inbuf point to beginning of the body. */
			message_get_body_size(inbuf, &body_size, (uoff_t)-1);

			update->rec->full_virtual_size =
				hdr_size.virtual_size + body_size.virtual_size;
		}
	}

	if (ctx.envelope != NULL) {
		t_push();
		value = imap_envelope_get_part_data(ctx.envelope);
		update->index->update_field(update, FIELD_TYPE_ENVELOPE,
					    value, 0);
		t_pop();

		pool_unref(ctx.envelope_pool);
	}
}