backend/internal/store/models.go

// Package store defines the persistence layer for CarrotAssistant.
//
// All persistent structured state lives here: admin accounts, applications,
// model configurations, skill metadata, chat sessions and messages, and
// audit logs. Skill *content* itself (the markdown file) lives on disk and
// is managed by the skill package; this package only stores the metadata
// needed to locate and govern that file (status, version, ownership).
package store

import (
	"time"

	"gorm.io/datatypes"
)

// AdminUser is an operator who can log in to the admin console.
type AdminUser struct {
	ID           int64     `gorm:"primaryKey;autoIncrement" json:"id"`
	Username     string    `gorm:"uniqueIndex;size:64;not null" json:"username"`
	PasswordHash string    `gorm:"size:255;not null" json:"-"`
	CreatedAt    time.Time `json:"created_at"`
	UpdatedAt    time.Time `json:"updated_at"`
}

// App is a target application (a forum, a resource site, ...). Each App owns
// a set of Skills and exposes a Chat API guarded by its access token.
type App struct {
	ID            int64     `gorm:"primaryKey;autoIncrement" json:"id"`
	Slug          string    `gorm:"uniqueIndex;size:64;not null" json:"slug"`
	Name          string    `gorm:"size:128;not null" json:"name"`
	Description   string    `gorm:"size:512" json:"description"`
	TokenHash     string    `gorm:"size:255;not null" json:"-"` // SHA-256 hash of the access token; never store plaintext
	ModelConfigID *int64    `gorm:"index" json:"model_config_id,omitempty"`
	Status        string    `gorm:"size:32;not null;default:'active'" json:"status"` // active | disabled
	CreatedAt     time.Time `json:"created_at"`
	UpdatedAt     time.Time `json:"updated_at"`
}

// ModelConfig describes an OpenAI-compatible LLM endpoint. Any provider
// speaking the OpenAI Chat Completions + tool-calling protocol (OpenAI,
// DeepSeek, Moonshot, vLLM, Ollama, ...) can be wired in here.
type ModelConfig struct {
	ID              int64     `gorm:"primaryKey;autoIncrement" json:"id"`
	Name            string    `gorm:"uniqueIndex;size:64;not null" json:"name"`
	BaseURL         string    `gorm:"size:255;not null" json:"base_url"`
	APIKeyEncrypted string    `gorm:"size:512;not null" json:"-"` // AES-GCM ciphertext, base64
	APIKeyPreview   string    `gorm:"size:16" json:"api_key_preview"` // last 4 chars, display only
	DefaultModel    string    `gorm:"size:64;not null" json:"default_model"`
	SupportsTools   bool      `gorm:"not null;default:true" json:"supports_tools"`
	MaxTokens       int       `gorm:"default:0" json:"max_tokens"` // 0 = leave unset
	CreatedAt       time.Time `json:"created_at"`
	UpdatedAt       time.Time `json:"updated_at"`
}

// Skill is the metadata row for a skill markdown file. The markdown content
// (system prompt + tool definitions) lives at FilePath; this row only governs
// lifecycle (draft/published/archived), versioning, and ownership.
type Skill struct {
	ID          int64     `gorm:"primaryKey;autoIncrement" json:"id"`
	AppID       int64     `gorm:"index;not null" json:"app_id"`
	Slug        string    `gorm:"size:64;not null" json:"slug"` // unique within app
	Name        string    `gorm:"size:128;not null" json:"name"`
	Description string    `gorm:"size:512" json:"description"`
	FilePath    string    `gorm:"size:512;not null" json:"file_path"` // path under SkillsDir
	Version     int       `gorm:"not null;default:1" json:"version"`
	Status      string    `gorm:"size:32;not null;default:'draft'" json:"status"` // draft | published | archived
	Source      string    `gorm:"size:32" json:"source"`                            // openapi | markdown | source | manual
	PublishedAt *time.Time `json:"published_at,omitempty"`
	CreatedAt   time.Time `json:"created_at"`
	UpdatedAt   time.Time `json:"updated_at"`
}

// Session is a chat conversation between an end-user and an App's assistant.
type Session struct {
	ID           string         `gorm:"primaryKey;type:text" json:"id"` // UUID
	AppID        int64          `gorm:"index;not null" json:"app_id"`
	Title        string         `gorm:"size:255" json:"title"`
	MessageCount int            `gorm:"not null;default:0" json:"message_count"`
	// PendingConfirmation, when non-empty, holds a JSON blob describing a
	// mutating tool call awaiting the user's approval. The chat stream pauses
	// until POST /chat/confirm resolves it. Empty = no pending call.
	PendingConfirmation datatypes.JSON `json:"pending_confirmation,omitempty"`
	CreatedAt            time.Time      `json:"created_at"`
	UpdatedAt            time.Time      `json:"updated_at"`
}

// Message is a single message within a Session. Role follows the OpenAI
// convention: system | user | assistant | tool. ToolCalls stores the
// assistant's tool call payload (JSON) when present.
type Message struct {
	ID         int64         `gorm:"primaryKey;autoIncrement" json:"id"`
	SessionID  string        `gorm:"index;not null" json:"session_id"`
	Role       string        `gorm:"size:32;not null" json:"role"` // system | user | assistant | tool
	Content    string        `gorm:"type:text" json:"content"`
	ToolCalls  datatypes.JSON `json:"tool_calls,omitempty"`
	ToolCallID string        `gorm:"size:64" json:"tool_call_id,omitempty"` // for role=tool, the call id it answers
	Tokens     int           `gorm:"default:0" json:"tokens"`
	CreatedAt  time.Time     `json:"created_at"`
}

// AuditLog records security-relevant actions for traceability.
type AuditLog struct {
	ID        int64          `gorm:"primaryKey;autoIncrement" json:"id"`
	AppID     *int64         `gorm:"index" json:"app_id,omitempty"`
	SessionID *string        `gorm:"index" json:"session_id,omitempty"`
	Actor     string         `gorm:"size:128" json:"actor"` // admin username, "system", app slug, ...
	Action    string         `gorm:"size:64;not null;index" json:"action"`
	Detail    datatypes.JSON `json:"detail"`
	CreatedAt time.Time      `gorm:"index" json:"created_at"`
}