package freedoc

import (
	"errors"
	"time"
)

var (
	ErrNotFound             = errors.New("freeform document not found")
	ErrForbidden            = errors.New("permission denied to access document")
	ErrConflict             = errors.New("optimistic concurrency conflict: version or sha mismatch")
	ErrInvalidParam         = errors.New("invalid parameter")
	ErrMessageNotExportable = errors.New("chat message is not exportable or content is empty")
)

// FreeformDocument 自由私密/共享文档元数据
type FreeformDocument struct {
	DocID               string     `json:"doc_id"`
	ProjectID           int64      `json:"project_id"`
	OwnerUserID         int        `json:"owner_user_id"`
	SourceMessageID     *int64     `json:"source_message_id,omitempty"`
	SourceContentSHA256 string     `json:"source_content_sha256"`
	ClientKey           *string    `json:"client_key,omitempty"`
	Title               string     `json:"title"`
	GovernanceMode      string     `json:"governance_mode"` // 恒为 'freeform'
	Space               string     `json:"space"`           // 'my_private' | 'project_shared' | 'trash'
	CurrentVersionID    int        `json:"current_version_id"`
	CurrentSHA256       string     `json:"current_sha256"`
	// 上传附件注册时持久化的源文件元数据；非上传文档恒为零值。
	SourceFilename  string `json:"source_filename,omitempty"`
	SourceMimeType  string `json:"source_mime_type,omitempty"`
	SourceSizeBytes int64  `json:"source_size_bytes,omitempty"`
	SourceAssetID   int64  `json:"source_asset_id,omitempty"`
	IsDeleted       bool       `json:"is_deleted"`
	DeletedAt           *time.Time `json:"deleted_at,omitempty"`
	CreatedAt           time.Time  `json:"created_at"`
	UpdatedAt           time.Time  `json:"updated_at"`
}

// FreeformDocumentVersion 自由文档历史版本快照
type FreeformDocumentVersion struct {
	ID              int64     `json:"id"`
	DocID           string    `json:"doc_id"`
	VersionNo       int       `json:"version_no"`
	ContentSHA256   string    `json:"content_sha256"`
	ContentMarkdown string    `json:"content_markdown"`
	CreatedBy       int       `json:"created_by"`
	ChangeSummary   string    `json:"change_summary"`
	CreatedAt       time.Time `json:"created_at"`
}

// FreeformDocDetail 自由文档详情（含当前版本 Markdown 正文）
type FreeformDocDetail struct {
	Document FreeformDocument `json:"document"`
	Content  string           `json:"content_markdown"`
}

// FreeformDocSummary 列表项概要
type FreeformDocSummary struct {
	DocID            string    `json:"doc_id"`
	ProjectID        int64     `json:"project_id"`
	OwnerUserID      int       `json:"owner_user_id"`
	Title            string    `json:"title"`
	Space            string    `json:"space"`
	CurrentVersionID int       `json:"current_version_id"`
	CurrentSHA256    string    `json:"current_sha256"`
	// 上传附件注册时持久化的源文件元数据；非上传文档恒为零值。
	SourceFilename  string `json:"source_filename,omitempty"`
	SourceMimeType  string `json:"source_mime_type,omitempty"`
	SourceSizeBytes int64  `json:"source_size_bytes,omitempty"`
	SourceAssetID   int64  `json:"source_asset_id,omitempty"`
	CreatedAt        time.Time `json:"created_at"`
	UpdatedAt        time.Time `json:"updated_at"`
}

// CreateFromMessageRequest 从单条消息保存到私密文档请求
type CreateFromMessageRequest struct {
	MessageID      int64  `json:"message_id"`
	ProjectID      int64  `json:"project_id"`
	Title          string `json:"title,omitempty"`
	ExpectedSHA256 string `json:"expected_sha256,omitempty"`
}

// CreateFreeformDocRequest 直接创建空白/自定义自由文档请求（上传附件即时注册事实源）
type CreateFreeformDocRequest struct {
	ProjectID       int64  `json:"project_id"`
	Title           string `json:"title"`
	ContentMarkdown string `json:"content_markdown"`
	Space           string `json:"space,omitempty"` // 默认 'my_private'
	// ClientKey 可选幂等键（如 doc-upload-{ts}-{idx}），同用户重复提交返回已有文档
	ClientKey string `json:"client_key,omitempty"`
	// 可选上传源文件元数据：换设备/共享后恢复文件预览与路由的事实源。
	SourceFilename  string `json:"source_filename,omitempty"`
	SourceMimeType  string `json:"source_mime_type,omitempty"`
	SourceSizeBytes int64  `json:"source_size_bytes,omitempty"`
	SourceAssetID   int64  `json:"source_asset_id,omitempty"`
}

// UpdateFreeformDocRequest 更新自由文档请求
type UpdateFreeformDocRequest struct {
	Title           *string `json:"title,omitempty"`
	ContentMarkdown *string `json:"content_markdown,omitempty"`
	ChangeSummary   string  `json:"change_summary,omitempty"`
	ExpectedVersion *int    `json:"expected_version,omitempty"`
	ExpectedSHA256  *string `json:"expected_sha256,omitempty"`
}

// summary 投影为列表概要（内存模式与 PG 行扫描共用同一字段集）。
func (d FreeformDocument) summary() FreeformDocSummary {
	return FreeformDocSummary{
		DocID:            d.DocID,
		ProjectID:        d.ProjectID,
		OwnerUserID:      d.OwnerUserID,
		Title:            d.Title,
		Space:            d.Space,
		CurrentVersionID: d.CurrentVersionID,
		CurrentSHA256:    d.CurrentSHA256,
		SourceFilename:   d.SourceFilename,
		SourceMimeType:   d.SourceMimeType,
		SourceSizeBytes:  d.SourceSizeBytes,
		SourceAssetID:    d.SourceAssetID,
		CreatedAt:        d.CreatedAt,
		UpdatedAt:        d.UpdatedAt,
	}
}