package sqlite

import (
	"context"
	"fmt"
	"strings"
)

const (
	defaultLogicalGroupRoutePolicy = "priority"
	defaultLogicalGroupStickyMode  = "conversation_preferred"
	defaultConversationTTLSeconds  = 7200
	defaultUserModelTTLSeconds     = 1800
	defaultFailoverThreshold       = 2
	defaultCooldownSeconds         = 600
)

type LogicalGroup struct {
	ID                     int64
	LogicalGroupID         string
	DisplayName            string
	Status                 string
	Description            string
	RoutePolicy            string
	StickyMode             string
	ConversationTTLSeconds int
	UserModelTTLSeconds    int
	FailoverThreshold      int
	CooldownSeconds        int
	CreatedAt              string
	UpdatedAt              string
}

type LogicalGroupsRepo struct {
	db execQuerier
}

func newLogicalGroupsRepo(db execQuerier) *LogicalGroupsRepo {
	return &LogicalGroupsRepo{db: db}
}

func (r *LogicalGroupsRepo) Create(ctx context.Context, group LogicalGroup) (int64, error) {
	group, err := normalizeLogicalGroup(group)
	if err != nil {
		return 0, err
	}

	result, err := r.db.ExecContext(
		ctx,
		`INSERT INTO logical_groups (
			logical_group_id,
			display_name,
			status,
			description,
			route_policy,
			sticky_mode,
			conversation_ttl_seconds,
			user_model_ttl_seconds,
			failover_threshold,
			cooldown_seconds
		) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		group.LogicalGroupID,
		group.DisplayName,
		group.Status,
		group.Description,
		group.RoutePolicy,
		group.StickyMode,
		group.ConversationTTLSeconds,
		group.UserModelTTLSeconds,
		group.FailoverThreshold,
		group.CooldownSeconds,
	)
	if err != nil {
		return 0, fmt.Errorf("insert logical group %q: %w", group.LogicalGroupID, err)
	}

	id, err := result.LastInsertId()
	if err != nil {
		return 0, fmt.Errorf("read inserted logical group id for %q: %w", group.LogicalGroupID, err)
	}
	return id, nil
}

func (r *LogicalGroupsRepo) GetByLogicalGroupID(ctx context.Context, logicalGroupID string) (LogicalGroup, error) {
	logicalGroupID = strings.TrimSpace(logicalGroupID)
	if logicalGroupID == "" {
		return LogicalGroup{}, fmt.Errorf("logical_group_id is required")
	}

	var group LogicalGroup
	if err := r.db.QueryRowContext(
		ctx,
		`SELECT id, logical_group_id, display_name, status, description, route_policy, sticky_mode, conversation_ttl_seconds, user_model_ttl_seconds, failover_threshold, cooldown_seconds, created_at, updated_at
		FROM logical_groups
		WHERE logical_group_id = ?`,
		logicalGroupID,
	).Scan(
		&group.ID,
		&group.LogicalGroupID,
		&group.DisplayName,
		&group.Status,
		&group.Description,
		&group.RoutePolicy,
		&group.StickyMode,
		&group.ConversationTTLSeconds,
		&group.UserModelTTLSeconds,
		&group.FailoverThreshold,
		&group.CooldownSeconds,
		&group.CreatedAt,
		&group.UpdatedAt,
	); err != nil {
		return LogicalGroup{}, err
	}
	return group, nil
}

func (r *LogicalGroupsRepo) List(ctx context.Context) ([]LogicalGroup, error) {
	rows, err := r.db.QueryContext(
		ctx,
		`SELECT id, logical_group_id, display_name, status, description, route_policy, sticky_mode, conversation_ttl_seconds, user_model_ttl_seconds, failover_threshold, cooldown_seconds, created_at, updated_at
		FROM logical_groups
		ORDER BY id ASC`,
	)
	if err != nil {
		return nil, fmt.Errorf("list logical groups: %w", err)
	}
	defer rows.Close()

	groups := make([]LogicalGroup, 0)
	for rows.Next() {
		var group LogicalGroup
		if err := rows.Scan(
			&group.ID,
			&group.LogicalGroupID,
			&group.DisplayName,
			&group.Status,
			&group.Description,
			&group.RoutePolicy,
			&group.StickyMode,
			&group.ConversationTTLSeconds,
			&group.UserModelTTLSeconds,
			&group.FailoverThreshold,
			&group.CooldownSeconds,
			&group.CreatedAt,
			&group.UpdatedAt,
		); err != nil {
			return nil, fmt.Errorf("scan logical group: %w", err)
		}
		groups = append(groups, group)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("iterate logical groups: %w", err)
	}
	return groups, nil
}

func (r *LogicalGroupsRepo) UpdateByLogicalGroupID(ctx context.Context, group LogicalGroup) error {
	group, err := normalizeLogicalGroup(group)
	if err != nil {
		return err
	}

	result, err := r.db.ExecContext(
		ctx,
		`UPDATE logical_groups
		SET display_name = ?, status = ?, description = ?, route_policy = ?, sticky_mode = ?, conversation_ttl_seconds = ?, user_model_ttl_seconds = ?, failover_threshold = ?, cooldown_seconds = ?, updated_at = CURRENT_TIMESTAMP
		WHERE logical_group_id = ?`,
		group.DisplayName,
		group.Status,
		group.Description,
		group.RoutePolicy,
		group.StickyMode,
		group.ConversationTTLSeconds,
		group.UserModelTTLSeconds,
		group.FailoverThreshold,
		group.CooldownSeconds,
		group.LogicalGroupID,
	)
	if err != nil {
		return fmt.Errorf("update logical group %q: %w", group.LogicalGroupID, err)
	}
	affected, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("read updated logical group rows for %q: %w", group.LogicalGroupID, err)
	}
	if affected == 0 {
		return fmt.Errorf("logical group %q not found", group.LogicalGroupID)
	}
	return nil
}

func (r *LogicalGroupsRepo) DeleteByLogicalGroupID(ctx context.Context, logicalGroupID string) error {
	logicalGroupID = strings.TrimSpace(logicalGroupID)
	if logicalGroupID == "" {
		return fmt.Errorf("logical_group_id is required")
	}

	result, err := r.db.ExecContext(ctx, `DELETE FROM logical_groups WHERE logical_group_id = ?`, logicalGroupID)
	if err != nil {
		return fmt.Errorf("delete logical group %q: %w", logicalGroupID, err)
	}
	affected, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("read deleted logical group rows for %q: %w", logicalGroupID, err)
	}
	if affected == 0 {
		return fmt.Errorf("logical group %q not found", logicalGroupID)
	}
	return nil
}

func normalizeLogicalGroup(group LogicalGroup) (LogicalGroup, error) {
	group.LogicalGroupID = strings.TrimSpace(group.LogicalGroupID)
	group.DisplayName = strings.TrimSpace(group.DisplayName)
	group.Status = strings.TrimSpace(group.Status)
	group.Description = strings.TrimSpace(group.Description)
	group.RoutePolicy = strings.TrimSpace(group.RoutePolicy)
	group.StickyMode = strings.TrimSpace(group.StickyMode)

	switch {
	case group.LogicalGroupID == "":
		return LogicalGroup{}, fmt.Errorf("logical_group_id is required")
	case group.DisplayName == "":
		return LogicalGroup{}, fmt.Errorf("display_name is required")
	case group.Status == "":
		return LogicalGroup{}, fmt.Errorf("status is required")
	}

	if group.RoutePolicy == "" {
		group.RoutePolicy = defaultLogicalGroupRoutePolicy
	}
	if group.StickyMode == "" {
		group.StickyMode = defaultLogicalGroupStickyMode
	}
	if group.ConversationTTLSeconds <= 0 {
		group.ConversationTTLSeconds = defaultConversationTTLSeconds
	}
	if group.UserModelTTLSeconds <= 0 {
		group.UserModelTTLSeconds = defaultUserModelTTLSeconds
	}
	if group.FailoverThreshold <= 0 {
		group.FailoverThreshold = defaultFailoverThreshold
	}
	if group.CooldownSeconds <= 0 {
		group.CooldownSeconds = defaultCooldownSeconds
	}

	return group, nil
}