second commit

internal/autoassignment/model.go

@@ -0,0 +1,102 @@
+package autoassignment
+
+// GORM models for the auto-assignment system.
+//
+// Reference: Chatwoot AutoAssignment pattern
+//   - AssignmentPolicy: global policy for how conversations are assigned
+//     (round_robin, longest_waiting). Has fair_distribution_limit and
+//     fair_distribution_window for rate limiting per agent.
+//   - InboxAssignmentPolicy: per-inbox override of the global policy.
+//     Each inbox can have its own assignment policy and rate limits.
+//
+// Pattern: gochat models embed model.Base (ID, CreatedAt, UpdatedAt, DeletedAt),
+// use TableName() method, and use gorm struct tags.
+
+import (
+	"github.com/gochat/gochat/internal/model"
+)
+
+// AssignmentPolicyType defines the type of auto-assignment policy.
+type AssignmentPolicyType string
+
+const (
+	// PolicyRoundRobin assigns conversations to agents in round-robin order.
+	// Reference: Chatwoot InboxRoundRobinService
+	PolicyRoundRobin AssignmentPolicyType = "round_robin"
+
+	// PolicyLongestWaiting assigns conversations to the agent with the
+	// longest idle time since their last assignment.
+	// Reference: Chatwoot "longest_waiting" policy (planned feature)
+	PolicyLongestWaiting AssignmentPolicyType = "longest_waiting"
+
+	// PolicyLowestLoad assigns conversations to the agent with the
+	// fewest currently open conversations.
+	// Reference: Chatwoot "least_busy" concept — agent with lowest workload.
+	PolicyLowestLoad AssignmentPolicyType = "lowest_load"
+)
+
+// AssignmentPolicy represents the global auto-assignment policy for an account.
+// Reference: Chatwoot AssignmentPolicy model
+//   - Defines how unassigned conversations are distributed among agents
+//   - fair_distribution_limit: max assignments per agent per window (default 5)
+//   - fair_distribution_window: time window in seconds for rate limiting (default 300 = 5 min)
+type AssignmentPolicy struct {
+	model.Base
+	AccountID              uint               `gorm:"index;not null" json:"account_id"`
+	Policy                 AssignmentPolicyType `gorm:"size:50;default:round_robin" json:"policy"`
+	FairDistributionLimit  int                `gorm:"default:5" json:"fair_distribution_limit"`
+	FairDistributionWindow int                `gorm:"default:300" json:"fair_distribution_window"` // seconds
+	Active                 bool               `gorm:"default:true" json:"active"`
+}
+
+func (AssignmentPolicy) TableName() string { return "assignment_policies" }
+
+// InboxAssignmentPolicy represents a per-inbox override of the global assignment policy.
+// Reference: Chatwoot InboxAssignmentPolicy model
+//   - Each inbox can override the account-level policy
+//   - If no inbox-specific policy exists, the account policy is used
+type InboxAssignmentPolicy struct {
+	model.Base
+	AccountID              uint               `gorm:"index;not null" json:"account_id"`
+	InboxID                uint               `gorm:"uniqueIndex;not null" json:"inbox_id"`
+	Policy                 AssignmentPolicyType `gorm:"size:50;default:round_robin" json:"policy"`
+	FairDistributionLimit  int                `gorm:"default:5" json:"fair_distribution_limit"`
+	FairDistributionWindow int                `gorm:"default:300" json:"fair_distribution_window"` // seconds
+	Active                 bool               `gorm:"default:true" json:"active"`
+}
+
+func (InboxAssignmentPolicy) TableName() string { return "inbox_assignment_policies" }
+
+// EffectivePolicy returns the effective assignment policy for a given inbox.
+// If the inbox has a specific policy, it is used; otherwise the account policy is used.
+func EffectivePolicy(accountPolicy *AssignmentPolicy, inboxPolicy *InboxAssignmentPolicy) AssignmentPolicyType {
+	if inboxPolicy != nil && inboxPolicy.Active {
+		return inboxPolicy.Policy
+	}
+	if accountPolicy != nil && accountPolicy.Active {
+		return accountPolicy.Policy
+	}
+	return PolicyRoundRobin // default
+}
+
+// EffectiveLimit returns the effective fair distribution limit for a given inbox.
+func EffectiveLimit(accountPolicy *AssignmentPolicy, inboxPolicy *InboxAssignmentPolicy) int {
+	if inboxPolicy != nil && inboxPolicy.Active && inboxPolicy.FairDistributionLimit > 0 {
+		return inboxPolicy.FairDistributionLimit
+	}
+	if accountPolicy != nil && accountPolicy.FairDistributionLimit > 0 {
+		return accountPolicy.FairDistributionLimit
+	}
+	return 5 // default
+}
+
+// EffectiveWindow returns the effective fair distribution window (in seconds).
+func EffectiveWindow(accountPolicy *AssignmentPolicy, inboxPolicy *InboxAssignmentPolicy) int {
+	if inboxPolicy != nil && inboxPolicy.Active && inboxPolicy.FairDistributionWindow > 0 {
+		return inboxPolicy.FairDistributionWindow
+	}
+	if accountPolicy != nil && accountPolicy.FairDistributionWindow > 0 {
+		return accountPolicy.FairDistributionWindow
+	}
+	return 300 // default (5 minutes)
+}