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
}

// FormatGermanDateTime formats an ISO-8601 string into "25. Okt. 2026 - 15:40 Uhr"
func FormatGermanDateTime(isoStr string) string {
	if isoStr == "" {
		return ""
	}
	var t time.Time
	var err error
	formats := []string{
		time.RFC3339Nano,
		time.RFC3339,
		"2006-01-02T15:04:05Z07:00",
		"2006-01-02T15:04:05",
		"2006-01-02 15:04:05",
		"2006-01-02",
	}
	for _, f := range formats {
		if parsed, parseErr := time.Parse(f, isoStr); parseErr == nil {
			t = parsed
			err = nil
			break
		} else {
			err = parseErr
		}
	}
	if err != nil {
		return isoStr
	}

	t = t.Local()

	germanMonths := map[time.Month]string{
		time.January:   "Jan.",
		time.February:  "Feb.",
		time.March:     "März",
		time.April:     "Apr.",
		time.May:       "Mai",
		time.June:      "Juni",
		time.July:      "Juli",
		time.August:     "Aug.",
		time.September: "Sept.",
		time.October:   "Okt.",
		time.November:  "Nov.",
		time.December:  "Dez.",
	}
	mStr := germanMonths[t.Month()]
	if mStr == "" {
		mStr = t.Format("Jan")
	}

	return fmt.Sprintf("%d. %s %d - %02d:%02d Uhr", t.Day(), mStr, t.Year(), t.Hour(), t.Minute())
}

type User struct {
	ID                  string   `json:"id"`
	Email               string   `json:"email"`
	Username            string   `json:"username,omitempty"`
	PasswordHash        string   `json:"-"`
	DisplayName         string   `json:"displayName"`
	AvatarURL           string   `json:"avatarUrl,omitempty"`
	Role                string   `json:"role"` // admin | member
	IsActive            bool     `json:"isActive"`
	AlarmChannels       []string `json:"alarmChannels"` // email | discord | webhook
	AlarmEmail          string   `json:"alarmEmail"`
	DiscordWebhookURL   string   `json:"discordWebhookUrl"`
	CustomWebhookURL    string   `json:"customWebhookUrl"`
	NotifyBeforeMinutes int      `json:"notifyBeforeMinutes"`
	CreatedAt           string   `json:"createdAt"`
}

type UserInvite struct {
	ID        string `json:"id"`
	Code      string `json:"code"`
	Email     string `json:"email,omitempty"`
	Role      string `json:"role"` // member | admin
	TeamID    string `json:"teamId,omitempty"`
	TeamName  string `json:"teamName,omitempty"`
	CreatedBy string `json:"createdBy"`
	ExpiresAt string `json:"expiresAt"`
	UsedBy    string `json:"usedBy,omitempty"`
	CreatedAt string `json:"createdAt"`
}

type ThoughtStatus string

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

type SubTask struct {
	ID          string `json:"id"`
	Title       string `json:"title"`
	IsCompleted bool   `json:"isCompleted"`
	CreatedAt   string `json:"createdAt,omitempty"`
}

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"`
	TaskListID     string        `json:"taskListId,omitempty"`
	KanbanStatus   string        `json:"kanbanStatus,omitempty"` // todo | in_progress | done
	Notes          string        `json:"notes,omitempty"`
	Subtasks       []SubTask     `json:"subtasks"`
	AlarmSent      bool          `json:"alarmSent,omitempty"`
	SortOrder      int           `json:"sortOrder"`
	CreatedAt      string        `json:"createdAt"`
	TriagedAt      string        `json:"triagedAt,omitempty"`
}

type ThoughtReorderItem struct {
	ID           string  `json:"id"`
	SortOrder    int     `json:"sortOrder"`
	KanbanStatus *string `json:"kanbanStatus,omitempty"`
}

type ListItemReorderItem struct {
	ID        string  `json:"id"`
	SortOrder int     `json:"sortOrder"`
	Category  *string `json:"category,omitempty"`
	Content   *string `json:"content,omitempty"`
}

type TaskListShare struct {
	ID         string `json:"id"`
	TaskListID string `json:"taskListId"`
	TargetType string `json:"targetType"` // team | user
	TargetID   string `json:"targetId"`
	TargetName string `json:"targetName,omitempty"`
	Email      string `json:"email,omitempty"`
	AvatarURL  string `json:"avatarUrl,omitempty"`
	CreatedAt  string `json:"createdAt"`
}

type TaskListMember struct {
	UserID      string `json:"userId"`
	DisplayName string `json:"displayName"`
	Email       string `json:"email"`
	AvatarURL   string `json:"avatarUrl,omitempty"`
	Role        string `json:"role"` // owner | member
}

type KanbanColumn struct {
	ID     string `json:"id"`
	Name   string `json:"name"`
	Color  string `json:"color,omitempty"`
	IsDone bool   `json:"isDone,omitempty"`
}

type TaskList struct {
	ID         string           `json:"id"`
	UserID     string           `json:"userId"`
	SpaceID    string           `json:"spaceId,omitempty"`
	SpaceName  string           `json:"spaceName,omitempty"`
	TeamID     string           `json:"teamId,omitempty"`
	TeamName   string           `json:"teamName,omitempty"`
	OwnerName  string           `json:"ownerName,omitempty"`
	IsOwner    bool             `json:"isOwner"`
	Members    []TaskListMember `json:"members,omitempty"`
	Shares     []TaskListShare  `json:"shares,omitempty"`
	Columns    []KanbanColumn   `json:"columns,omitempty"`
	Title      string           `json:"title"`
	Icon       string           `json:"icon"`
	Color      string           `json:"color"`
	TasksCount int              `json:"tasksCount,omitempty"`
	CreatedAt  string           `json:"createdAt"`
	UpdatedAt  string           `json:"updatedAt"`
}

type Organization struct {
	ID        string `json:"id"`
	Name      string `json:"name"`
	OwnerID   string `json:"ownerId"`
	Teams     []Team `json:"teams,omitempty"`
	CreatedAt string `json:"createdAt"`
}

type Team struct {
	ID          string       `json:"id"`
	OrgID       string       `json:"orgId,omitempty"`
	Name        string       `json:"name"`
	Description string       `json:"description"`
	Members     []TeamMember `json:"members"`
	CreatedAt   string       `json:"createdAt"`
}

type TeamMember struct {
	TeamID      string `json:"teamId"`
	UserID      string `json:"userId"`
	DisplayName string `json:"displayName"`
	Email       string `json:"email"`
	AvatarURL   string `json:"avatarUrl,omitempty"`
	Role        string `json:"role"` // admin | member
	JoinedAt    string `json:"joinedAt"`
}

type SystemSettings struct {
	SharingMode          string `json:"sharingMode"` // open | teams_only | strict_private
	AllowRegistration    bool   `json:"allowRegistration"`
	InstanceName         string `json:"instanceName"`
	SMTPHost             string `json:"smtpHost"`
	SMTPPort             string `json:"smtpPort"`
	SMTPUser             string `json:"smtpUser"`
	SMTPPass             string `json:"smtpPass"`
	SMTPFrom             string `json:"smtpFrom"`
	SMTPTLS              bool   `json:"smtpTls"`
	SMTPConfiguredViaEnv bool   `json:"smtpConfiguredViaEnv,omitempty"`
}

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

type DocShare struct {
	ID          string `json:"id"`
	DocID       string `json:"docId"`
	TargetType  string `json:"targetType,omitempty"` // user | team
	TargetID    string `json:"targetId,omitempty"`
	TargetName  string `json:"targetName,omitempty"`
	UserID      string `json:"userId,omitempty"`
	UserEmail   string `json:"userEmail,omitempty"`
	DisplayName string `json:"displayName,omitempty"`
	Permission  string `json:"permission"` // read | write
	CreatedBy   string `json:"createdBy"`
	CreatedAt   string `json:"createdAt"`
}

type DocLockInfo struct {
	DocID     string `json:"docId"`
	UserID    string `json:"userId"`
	UserName  string `json:"userName"`
	ExpiresAt string `json:"expiresAt"`
}

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"`
	FolderPath string          `json:"folderPath,omitempty"`
	IsPinned   bool            `json:"isPinned"`
	IsArchived bool            `json:"isArchived"`
	CreatedAt  string          `json:"createdAt"`
	UpdatedAt  string          `json:"updatedAt"`

	// Collaboration & Permissions
	Permission string     `json:"permission"` // owner | write | read
	IsOwner    bool       `json:"isOwner"`
	OwnerName  string     `json:"ownerName,omitempty"`
	SharedWith []DocShare `json:"sharedWith,omitempty"`
}

type TagSummary struct {
	Tag   string `json:"tag"`
	Count int    `json:"count"`
}

type MatchedTagBlock struct {
	RootBlock DocumentBlock   `json:"rootBlock"`
	Children  []DocumentBlock `json:"children"`
}

type TagDocumentGroup struct {
	DocID         string            `json:"docId"`
	Title         string            `json:"title"`
	Icon          string            `json:"icon"`
	FolderPath    string            `json:"folderPath"`
	UpdatedAt     string            `json:"updatedAt"`
	IsOwner       bool              `json:"isOwner"`
	Permission    string            `json:"permission"`
	OwnerName     string            `json:"ownerName,omitempty"`
	MatchedBlocks []MatchedTagBlock `json:"matchedBlocks"`
}

type TagDetails struct {
	Tag           string             `json:"tag"`
	NoteContent   string             `json:"noteContent"`
	NoteUpdatedAt string             `json:"noteUpdatedAt,omitempty"`
	Documents     []TagDocumentGroup `json:"documents"`
	TotalMatches  int                `json:"totalMatches"`
}

type ListShare struct {
	ID         string `json:"id"`
	ListID     string `json:"listId"`
	TargetType string `json:"targetType"` // team | user
	TargetID   string `json:"targetId"`
	TargetName string `json:"targetName,omitempty"`
	Email      string `json:"email,omitempty"`
	Role       string `json:"role"` // editor | viewer
	CreatedBy  string `json:"createdBy"`
	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"`
	UserID    string      `json:"userId"`
	OwnerName string      `json:"ownerName,omitempty"`
	IsOwner   bool        `json:"isOwner"`
	Role      string      `json:"role,omitempty"` // editor | viewer
	Title     string      `json:"title"`
	Icon      string      `json:"icon"`
	ListType  string      `json:"listType"` // shopping | checklist | vacation
	Items     []ListItem  `json:"items"`
	Shares    []ListShare `json:"shares,omitempty"`
	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
	ListID    string      `json:"list_id"`
	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"`
	DocsTodosOpenCount int `json:"docsTodosOpenCount"`
	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"`
	Lists      []SharedList `json:"lists"`
	TaskLists  []TaskList   `json:"taskLists,omitempty"`
}