package sqlite

import (
	"context"
	"database/sql"
	"fmt"
	"strings"
	"time"

	"github.com/steveyegge/beads/internal/types"
)

// GetCloseReason retrieves the close reason from the most recent closed event for an issue
func (s *SQLiteStorage) GetCloseReason(ctx context.Context, issueID string) (string, error) {
	var comment sql.NullString
	err := s.db.QueryRowContext(ctx, `
		SELECT comment FROM events
		WHERE issue_id = ? AND event_type = ?
		ORDER BY created_at DESC
		LIMIT 1
	`, issueID, types.EventClosed).Scan(&comment)

	if err == sql.ErrNoRows {
		return "", nil
	}
	if err != nil {
		return "", fmt.Errorf("failed to get close reason: %w", err)
	}
	if comment.Valid {
		return comment.String, nil
	}
	return "", nil
}

// GetCloseReasonsForIssues retrieves close reasons for multiple issues in a single query
func (s *SQLiteStorage) GetCloseReasonsForIssues(ctx context.Context, issueIDs []string) (map[string]string, error) {
	result := make(map[string]string)
	if len(issueIDs) == 0 {
		return result, nil
	}

	// Build placeholders for IN clause
	placeholders := make([]string, len(issueIDs))
	args := make([]interface{}, len(issueIDs)+1)
	args[0] = types.EventClosed
	for i, id := range issueIDs {
		placeholders[i] = "?"
		args[i+1] = id
	}

	// Use a subquery to get the most recent closed event for each issue
	// #nosec G201 - safe SQL with controlled formatting
	query := fmt.Sprintf(`
		SELECT e.issue_id, e.comment
		FROM events e
		INNER JOIN (
			SELECT issue_id, MAX(created_at) as max_created_at
			FROM events
			WHERE event_type = ? AND issue_id IN (%s)
			GROUP BY issue_id
		) latest ON e.issue_id = latest.issue_id AND e.created_at = latest.max_created_at
		WHERE e.event_type = ?
	`, strings.Join(placeholders, ", "))

	// Append event_type again for the outer WHERE clause
	args = append(args, types.EventClosed)

	rows, err := s.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("failed to get close reasons: %w", err)
	}
	defer func() { _ = rows.Close() }()

	for rows.Next() {
		var issueID string
		var comment sql.NullString
		if err := rows.Scan(&issueID, &comment); err != nil {
			return nil, fmt.Errorf("failed to scan close reason: %w", err)
		}
		if comment.Valid && comment.String != "" {
			result[issueID] = comment.String
		}
	}

	return result, nil
}

// GetIssueByExternalRef retrieves an issue by external reference
func (s *SQLiteStorage) GetIssueByExternalRef(ctx context.Context, externalRef string) (*types.Issue, error) {
	var issue types.Issue
	var closedAt sql.NullTime
	var estimatedMinutes sql.NullInt64
	var assignee sql.NullString
	var externalRefCol sql.NullString
	var compactedAt sql.NullTime
	var originalSize sql.NullInt64
	var contentHash sql.NullString
	var compactedAtCommit sql.NullString
	var sourceRepo sql.NullString
	var closeReason sql.NullString
	var deletedAt sql.NullString // TEXT column, not DATETIME - must parse manually
	var deletedBy sql.NullString
	var deleteReason sql.NullString
	var originalType sql.NullString
	// Messaging fields (bd-kwro)
	var sender sql.NullString
	var wisp sql.NullInt64
	// Pinned field (bd-7h5)
	var pinned sql.NullInt64
	// Template field (beads-1ra)
	var isTemplate sql.NullInt64
	// Gate fields (bd-udsi)
	var awaitType sql.NullString
	var awaitID sql.NullString
	var timeoutNs sql.NullInt64
	var waiters sql.NullString

	err := s.db.QueryRowContext(ctx, `
		SELECT id, content_hash, title, description, design, acceptance_criteria, notes,
		       status, priority, issue_type, assignee, estimated_minutes,
		       created_at, updated_at, closed_at, external_ref,
		       compaction_level, compacted_at, compacted_at_commit, original_size, source_repo, close_reason,
		       deleted_at, deleted_by, delete_reason, original_type,
		       sender, ephemeral, pinned, is_template,
		       await_type, await_id, timeout_ns, waiters
		FROM issues
		WHERE external_ref = ?
	`, externalRef).Scan(
		&issue.ID, &contentHash, &issue.Title, &issue.Description, &issue.Design,
		&issue.AcceptanceCriteria, &issue.Notes, &issue.Status,
		&issue.Priority, &issue.IssueType, &assignee, &estimatedMinutes,
		&issue.CreatedAt, &issue.UpdatedAt, &closedAt, &externalRefCol,
		&issue.CompactionLevel, &compactedAt, &compactedAtCommit, &originalSize, &sourceRepo, &closeReason,
		&deletedAt, &deletedBy, &deleteReason, &originalType,
		&sender, &wisp, &pinned, &isTemplate,
		&awaitType, &awaitID, &timeoutNs, &waiters,
	)

	if err == sql.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, fmt.Errorf("failed to get issue by external_ref: %w", err)
	}

	if contentHash.Valid {
		issue.ContentHash = contentHash.String
	}
	if closedAt.Valid {
		issue.ClosedAt = &closedAt.Time
	}
	if estimatedMinutes.Valid {
		mins := int(estimatedMinutes.Int64)
		issue.EstimatedMinutes = &mins
	}
	if assignee.Valid {
		issue.Assignee = assignee.String
	}
	if externalRefCol.Valid {
		issue.ExternalRef = &externalRefCol.String
	}
	if compactedAt.Valid {
		issue.CompactedAt = &compactedAt.Time
	}
	if compactedAtCommit.Valid {
		issue.CompactedAtCommit = &compactedAtCommit.String
	}
	if originalSize.Valid {
		issue.OriginalSize = int(originalSize.Int64)
	}
	if sourceRepo.Valid {
		issue.SourceRepo = sourceRepo.String
	}
	if closeReason.Valid {
		issue.CloseReason = closeReason.String
	}
	issue.DeletedAt = parseNullableTimeString(deletedAt)
	if deletedBy.Valid {
		issue.DeletedBy = deletedBy.String
	}
	if deleteReason.Valid {
		issue.DeleteReason = deleteReason.String
	}
	if originalType.Valid {
		issue.OriginalType = originalType.String
	}
	// Messaging fields (bd-kwro)
	if sender.Valid {
		issue.Sender = sender.String
	}
	if wisp.Valid && wisp.Int64 != 0 {
		issue.Wisp = true
	}
	// Pinned field (bd-7h5)
	if pinned.Valid && pinned.Int64 != 0 {
		issue.Pinned = true
	}
	// Template field (beads-1ra)
	if isTemplate.Valid && isTemplate.Int64 != 0 {
		issue.IsTemplate = true
	}
	// Gate fields (bd-udsi)
	if awaitType.Valid {
		issue.AwaitType = awaitType.String
	}
	if awaitID.Valid {
		issue.AwaitID = awaitID.String
	}
	if timeoutNs.Valid {
		issue.Timeout = time.Duration(timeoutNs.Int64)
	}
	if waiters.Valid && waiters.String != "" {
		issue.Waiters = parseJSONStringArray(waiters.String)
	}

	// Fetch labels for this issue
	labels, err := s.GetLabels(ctx, issue.ID)
	if err != nil {
		return nil, fmt.Errorf("failed to get labels: %w", err)
	}
	issue.Labels = labels

	return &issue, nil
}

// SearchIssues finds issues matching query and filters
func (s *SQLiteStorage) SearchIssues(ctx context.Context, query string, filter types.IssueFilter) ([]*types.Issue, error) {
	// Check for external database file modifications (daemon mode)
	s.checkFreshness()

	// Hold read lock during database operations to prevent reconnect() from
	// closing the connection mid-query (GH#607 race condition fix)
	s.reconnectMu.RLock()
	defer s.reconnectMu.RUnlock()

	whereClauses := []string{}
	args := []interface{}{}

	if query != "" {
		whereClauses = append(whereClauses, "(title LIKE ? OR description LIKE ? OR id LIKE ?)")
		pattern := "%" + query + "%"
		args = append(args, pattern, pattern, pattern)
	}

	if filter.TitleSearch != "" {
		whereClauses = append(whereClauses, "title LIKE ?")
		pattern := "%" + filter.TitleSearch + "%"
		args = append(args, pattern)
	}

	// Pattern matching
	if filter.TitleContains != "" {
		whereClauses = append(whereClauses, "title LIKE ?")
		args = append(args, "%"+filter.TitleContains+"%")
	}
	if filter.DescriptionContains != "" {
		whereClauses = append(whereClauses, "description LIKE ?")
		args = append(args, "%"+filter.DescriptionContains+"%")
	}
	if filter.NotesContains != "" {
		whereClauses = append(whereClauses, "notes LIKE ?")
		args = append(args, "%"+filter.NotesContains+"%")
	}

	if filter.Status != nil {
		whereClauses = append(whereClauses, "status = ?")
		args = append(args, *filter.Status)
	} else if !filter.IncludeTombstones {
		// Exclude tombstones by default unless explicitly filtering for them (bd-1bu)
		whereClauses = append(whereClauses, "status != ?")
		args = append(args, types.StatusTombstone)
	}

	if filter.Priority != nil {
		whereClauses = append(whereClauses, "priority = ?")
		args = append(args, *filter.Priority)
	}

	// Priority ranges
	if filter.PriorityMin != nil {
		whereClauses = append(whereClauses, "priority >= ?")
		args = append(args, *filter.PriorityMin)
	}
	if filter.PriorityMax != nil {
		whereClauses = append(whereClauses, "priority <= ?")
		args = append(args, *filter.PriorityMax)
	}

	if filter.IssueType != nil {
		whereClauses = append(whereClauses, "issue_type = ?")
		args = append(args, *filter.IssueType)
	}

	if filter.Assignee != nil {
		whereClauses = append(whereClauses, "assignee = ?")
		args = append(args, *filter.Assignee)
	}

	// Date ranges
	if filter.CreatedAfter != nil {
		whereClauses = append(whereClauses, "created_at > ?")
		args = append(args, filter.CreatedAfter.Format(time.RFC3339))
	}
	if filter.CreatedBefore != nil {
		whereClauses = append(whereClauses, "created_at < ?")
		args = append(args, filter.CreatedBefore.Format(time.RFC3339))
	}
	if filter.UpdatedAfter != nil {
		whereClauses = append(whereClauses, "updated_at > ?")
		args = append(args, filter.UpdatedAfter.Format(time.RFC3339))
	}
	if filter.UpdatedBefore != nil {
		whereClauses = append(whereClauses, "updated_at < ?")
		args = append(args, filter.UpdatedBefore.Format(time.RFC3339))
	}
	if filter.ClosedAfter != nil {
		whereClauses = append(whereClauses, "closed_at > ?")
		args = append(args, filter.ClosedAfter.Format(time.RFC3339))
	}
	if filter.ClosedBefore != nil {
		whereClauses = append(whereClauses, "closed_at < ?")
		args = append(args, filter.ClosedBefore.Format(time.RFC3339))
	}

	// Empty/null checks
	if filter.EmptyDescription {
		whereClauses = append(whereClauses, "(description IS NULL OR description = '')")
	}
	if filter.NoAssignee {
		whereClauses = append(whereClauses, "(assignee IS NULL OR assignee = '')")
	}
	if filter.NoLabels {
		whereClauses = append(whereClauses, "id NOT IN (SELECT DISTINCT issue_id FROM labels)")
	}

	// Label filtering: issue must have ALL specified labels
	if len(filter.Labels) > 0 {
		for _, label := range filter.Labels {
			whereClauses = append(whereClauses, "id IN (SELECT issue_id FROM labels WHERE label = ?)")
			args = append(args, label)
		}
	}

	// Label filtering (OR): issue must have AT LEAST ONE of these labels
	if len(filter.LabelsAny) > 0 {
		placeholders := make([]string, len(filter.LabelsAny))
		for i, label := range filter.LabelsAny {
			placeholders[i] = "?"
			args = append(args, label)
		}
		whereClauses = append(whereClauses, fmt.Sprintf("id IN (SELECT issue_id FROM labels WHERE label IN (%s))", strings.Join(placeholders, ", ")))
	}

	// ID filtering: match specific issue IDs
	if len(filter.IDs) > 0 {
		placeholders := make([]string, len(filter.IDs))
		for i, id := range filter.IDs {
			placeholders[i] = "?"
			args = append(args, id)
		}
		whereClauses = append(whereClauses, fmt.Sprintf("id IN (%s)", strings.Join(placeholders, ", ")))
	}

	// Wisp filtering (bd-kwro.9)
	if filter.Wisp != nil {
		if *filter.Wisp {
			whereClauses = append(whereClauses, "ephemeral = 1") // SQL column is still 'ephemeral'
		} else {
			whereClauses = append(whereClauses, "(ephemeral = 0 OR ephemeral IS NULL)")
		}
	}

	// Pinned filtering (bd-7h5)
	if filter.Pinned != nil {
		if *filter.Pinned {
			whereClauses = append(whereClauses, "pinned = 1")
		} else {
			whereClauses = append(whereClauses, "(pinned = 0 OR pinned IS NULL)")
		}
	}

	// Template filtering (beads-1ra)
	if filter.IsTemplate != nil {
		if *filter.IsTemplate {
			whereClauses = append(whereClauses, "is_template = 1")
		} else {
			whereClauses = append(whereClauses, "(is_template = 0 OR is_template IS NULL)")
		}
	}

	// Parent filtering (bd-yqhh): filter children by parent issue
	if filter.ParentID != nil {
		whereClauses = append(whereClauses, "id IN (SELECT issue_id FROM dependencies WHERE type = 'parent-child' AND depends_on_id = ?)")
		args = append(args, *filter.ParentID)
	}

	whereSQL := ""
	if len(whereClauses) > 0 {
		whereSQL = "WHERE " + strings.Join(whereClauses, " AND ")
	}

	limitSQL := ""
	if filter.Limit > 0 {
		limitSQL = " LIMIT ?"
		args = append(args, filter.Limit)
	}

	// #nosec G201 - safe SQL with controlled formatting
	querySQL := fmt.Sprintf(`
		SELECT id, content_hash, title, description, design, acceptance_criteria, notes,
		       status, priority, issue_type, assignee, estimated_minutes,
		       created_at, updated_at, closed_at, external_ref, source_repo, close_reason,
		       deleted_at, deleted_by, delete_reason, original_type,
		       sender, ephemeral, pinned, is_template,
		       await_type, await_id, timeout_ns, waiters
		FROM issues
		%s
		ORDER BY priority ASC, created_at DESC
		%s
	`, whereSQL, limitSQL)

	rows, err := s.db.QueryContext(ctx, querySQL, args...)
	if err != nil {
		return nil, fmt.Errorf("failed to search issues: %w", err)
	}
	defer func() { _ = rows.Close() }()

	return s.scanIssues(ctx, rows)
}