package domain

import (
	"crypto/rand"
	"encoding/hex"
	"fmt"
	"regexp"
	"strings"
	"time"
)

// NewID generates a readable prefixed ID as specified in BRAIN.md (e.g. th_4x8z19a0b1)
func NewID(prefix string) string {
	b := make([]byte, 5)
	_, _ = rand.Read(b)
	return fmt.Sprintf("%s_%s", prefix, hex.EncodeToString(b))
}

// NowISO returns the current UTC timestamp in ISO-8601 format
func NowISO() string {
	return time.Now().UTC().Format(time.RFC3339)
}

var hashtagRegex = regexp.MustCompile(`#([a-zA-Z0-9äöüÄÖÜß_-]+)`)

// ExtractTags extracts #hashtags from content
func ExtractTags(content string) []string {
	matches := hashtagRegex.FindAllStringSubmatch(content, -1)
	seen := make(map[string]bool)
	tags := make([]string, 0, len(matches))
	for _, m := range matches {
		if len(m) > 1 {
			tag := strings.ToLower(m[1])
			if !seen[tag] {
				seen[tag] = true
				tags = append(tags, tag)
			}
		}
	}
	return tags
}

type User struct {
	ID           string `json:"id"`
	Email        string `json:"email"`
	PasswordHash string `json:"-"`
	DisplayName  string `json:"displayName"`
	CreatedAt    string `json:"createdAt"`
}

type ThoughtStatus string

const (
	StatusInbox     ThoughtStatus = "inbox"
	StatusKept      ThoughtStatus = "kept"
	StatusDiscarded ThoughtStatus = "discarded"
	StatusConverted ThoughtStatus = "converted"
)

type Thought struct {
	ID             string        `json:"id"`
	UserID         string        `json:"userId"`
	Content        string        `json:"content"`
	Tags           []string      `json:"tags"`
	Priority       string        `json:"priority"` // low | normal | high | urgent
	Source         string        `json:"source"`   // manual | voice | webhook
	Status         ThoughtStatus `json:"status"`
	IsCompleted    bool          `json:"isCompleted"`
	ConvertedType  string        `json:"convertedType,omitempty"`  // task | document | list_item
	ConvertedRefID string        `json:"convertedRefId,omitempty"` // referenced entity ID
	DueDate        string        `json:"dueDate,omitempty"`
	CreatedAt      string        `json:"createdAt"`
	TriagedAt      string        `json:"triagedAt,omitempty"`
}

type DocumentBlock struct {
	ID      string `json:"id"`
	Type    string `json:"type"` // h1 | h2 | h3 | paragraph | todo | bullet | code | callout | divider
	Content string `json:"content"`
	Checked bool   `json:"checked,omitempty"`
	Lang    string `json:"lang,omitempty"`
}

type Document struct {
	ID         string          `json:"id"`
	UserID     string          `json:"userId"`
	SpaceID    string          `json:"spaceId,omitempty"`
	Title      string          `json:"title"`
	Icon       string          `json:"icon"`
	Content    string          `json:"content"`
	Blocks     []DocumentBlock `json:"blocks"`
	Tags       []string        `json:"tags"`
	IsPinned   bool            `json:"isPinned"`
	IsArchived bool            `json:"isArchived"`
	CreatedAt  string          `json:"createdAt"`
	UpdatedAt  string          `json:"updatedAt"`
}

type SpaceMember struct {
	SpaceID     string `json:"spaceId"`
	UserID      string `json:"userId"`
	DisplayName string `json:"displayName"`
	Email       string `json:"email"`
	Role        string `json:"role"` // owner | editor | viewer
	JoinedAt    string `json:"joinedAt"`
}

type Space struct {
	ID          string        `json:"id"`
	Name        string        `json:"name"`
	Icon        string        `json:"icon"`
	Description string        `json:"description"`
	InviteCode  string        `json:"inviteCode"`
	IsPersonal  bool          `json:"isPersonal"`
	OwnerID     string        `json:"ownerId"`
	Members     []SpaceMember `json:"members,omitempty"`
	ListsCount  int           `json:"listsCount"`
	CreatedAt   string        `json:"createdAt"`
}

type ListItem struct {
	ID              string `json:"id"`
	ListID          string `json:"listId"`
	Content         string `json:"content"`
	Category        string `json:"category,omitempty"`
	Quantity        string `json:"quantity,omitempty"`
	IsCompleted     bool   `json:"isCompleted"`
	CompletedBy     string `json:"completedBy,omitempty"`
	CompletedByName string `json:"completedByName,omitempty"`
	SortOrder       int    `json:"sortOrder"`
	CreatedAt       string `json:"createdAt"`
	CompletedAt     string `json:"completedAt,omitempty"`
}

type SharedList struct {
	ID        string     `json:"id"`
	SpaceID   string     `json:"spaceId"`
	Title     string     `json:"title"`
	Icon      string     `json:"icon"`
	ListType  string     `json:"listType"` // shopping | checklist | vacation
	Items     []ListItem `json:"items"`
	UpdatedAt string     `json:"updatedAt"`
	CreatedAt string     `json:"createdAt"`
}

type APIKey struct {
	ID         string `json:"id"`
	UserID     string `json:"userId"`
	Name       string `json:"name"`
	KeyPrefix  string `json:"keyPrefix"`
	KeyHash    string `json:"-"`
	RawKey     string `json:"rawKey,omitempty"` // Only returned once on creation
	Scopes     string `json:"scopes"`
	LastUsedAt string `json:"lastUsedAt,omitempty"`
	CreatedAt  string `json:"createdAt"`
}

type WSMessage struct {
	Event     string      `json:"event"` // ITEM_CREATED | ITEM_UPDATED | ITEM_TOGGLED | ITEM_DELETED | LIST_CLEARED | USER_PRESENCE
	SpaceID   string      `json:"space_id"`
	ListID    string      `json:"list_id,omitempty"`
	Payload   interface{} `json:"payload"`
	Timestamp string      `json:"timestamp"`
}

type DashboardStats struct {
	InboxCount     int `json:"inboxCount"`
	TasksOpenCount int `json:"tasksOpenCount"`
	TasksDoneCount int `json:"tasksDoneCount"`
	DocsCount      int `json:"docsCount"`
	ListsCount     int `json:"listsCount"`
	DiscardedCount int `json:"discardedCount"`
}

type FullExport struct {
	ExportedAt string       `json:"exportedAt"`
	Version    string       `json:"version"`
	User       User         `json:"user"`
	Thoughts   []Thought    `json:"thoughts"`
	Documents  []Document   `json:"documents"`
	Spaces     []Space      `json:"spaces"`
	Lists      []SharedList `json:"lists"`
}