package model

import (
	"encoding/json"
	"time"
)

// User represents a row in the `users` table.
//
// PasswordHash is tagged `json:"-"` so it never leaks via JSON marshalling
// even if a caller accidentally passes a User through response.JSON. It's a
// pointer because OAuth-only users have no password — *PasswordHash == nil
// means "this account can only sign in via a linked OAuth provider".
//
// UserSummary is the lightweight projection used in follower / following
// lists — just enough to render a row and link to the profile.
type UserSummary struct {
	// ID is populated only where the caller needs it (e.g. mention add/remove);
	// omitted from follower/like lists that link by handle.
	ID        string  `json:"id,omitempty"`
	Handle    string  `json:"handle"`
	Name      string  `json:"name"`
	AvatarURL *string `json:"avatar_url"`
}

// EmailVerifiedAt is a pointer so JSON-encoded users carry an explicit `null`
// when the user has not yet verified, instead of an omitted field — the
// frontend uses this to decide whether to show the "verify your email" ribbon.
type User struct {
	ID              string     `json:"id"`
	// Email is nullable: OAuth users (typically Facebook accounts with no
	// verified email on file) sign up without one and can fill it in later
	// from their profile.
	Email           *string    `json:"email"`
	Handle          string     `json:"handle"`
	Name            string     `json:"name"`
	AvatarURL       *string    `json:"avatar_url"`
	Role            string     `json:"role"`
	Plan            string     `json:"plan"` // "free" | "premium"
	// Country is the account's ISO-3166-1 alpha-2 code (e.g. "IN"),
	// captured best-effort at signup and editable from the profile form.
	// nil until known.
	Country *string `json:"country"`

	// --- Devotional profile (user-editable) ---
	// Gender is a free-but-constrained string ("male"|"female"|"other"),
	// nil when unspecified.
	Gender *string `json:"gender"`
	// Sampradaya is the devotee's spiritual lineage (a lowercase code,
	// e.g. "gaudiya"). Optional — new accounts default to "gaudiya" but it
	// can be cleared, so nil means "not specified".
	Sampradaya *string `json:"sampradaya"`
	// Initiated marks whether the devotee has received initiation.
	Initiated bool `json:"initiated"`
	// InitiatedAt is the initiation date (DATE column), nil when unknown or
	// not initiated.
	InitiatedAt *time.Time `json:"initiated_at"`
	// DailyChantingRounds is the devotee's daily japa round vow (1–1008),
	// nil when unspecified.
	DailyChantingRounds *int `json:"daily_chanting_rounds"`

	// --- Notification scheduling (system-managed; no UI yet) ---
	// PreferredChantingTime / PeakActiveTime store a local clock time as
	// "HH:MM". They're written silently by the backend to time automated
	// notifications; the scheduling logic ships later. nil until computed.
	PreferredChantingTime *string `json:"preferred_chanting_time"`
	PeakActiveTime        *string `json:"peak_active_time"`

	EmailVerifiedAt *time.Time `json:"email_verified_at"`
	PasswordHash    *string    `json:"-"`
	TokenVersion    int        `json:"-"`
	CreatedAt       time.Time  `json:"created_at"`
	UpdatedAt       time.Time  `json:"updated_at"`

	// BannedAt suspends the account when set: RequireAuth rejects the session
	// and LogIn refuses to issue a new one. nil = in good standing.
	BannedAt *time.Time `json:"banned_at,omitempty"`
}

// MarshalJSON adds a derived `has_password` flag so the frontend can pick
// "Change password" vs "Set a password" for OAuth-only accounts, without
// the password hash itself ever leaving the server.
func (u User) MarshalJSON() ([]byte, error) {
	type alias User
	return json.Marshal(&struct {
		alias
		HasPassword bool `json:"has_password"`
	}{
		alias:       alias(u),
		HasPassword: u.PasswordHash != nil,
	})
}

// AuthToken represents a row in the `auth_tokens` table.
// Used for both password reset and email verification flows.
type AuthToken struct {
	ID        string     `json:"id"`
	UserID    string     `json:"user_id"`
	Purpose   string     `json:"purpose"` // "password_reset" | "email_verification"
	TokenHash string     `json:"-"`
	ExpiresAt time.Time  `json:"expires_at"`
	UsedAt    *time.Time `json:"used_at,omitempty"`
	CreatedAt time.Time  `json:"created_at"`
}

const (
	PurposePasswordReset     = "password_reset"
	PurposeEmailVerification = "email_verification"
	// PurposeLoginOTP is a 6-digit one-time code emailed to a user whose
	// account has been unverified for >30 days. Verification happens
	// per-user (FindValidForUser), so the 1M-keyspace can't be brute-forced
	// offline by hash collision — only online against rate limits.
	PurposeLoginOTP = "login_otp"
)

// OAuthAccount represents a row in the `oauth_accounts` table — one entry
// per (provider, provider_user_id). A single user can have several linked
// providers.
type OAuthAccount struct {
	ID             string    `json:"id"`
	UserID         string    `json:"user_id"`
	Provider       string    `json:"provider"`
	ProviderUserID string    `json:"provider_user_id"`
	Email          *string   `json:"email"`
	Name           *string   `json:"name"`
	AvatarURL      *string   `json:"avatar_url"`
	CreatedAt      time.Time `json:"created_at"`
	UpdatedAt      time.Time `json:"updated_at"`
}

// ShortURL represents a shortened URL.
type ShortURL struct {
	ID         string     `json:"id"`
	Slug       string     `json:"slug"`
	TargetURL  string     `json:"target_url"`
	CreatedBy  *string    `json:"created_by,omitempty"`
	ClickCount int64      `json:"click_count"`
	CreatedAt  time.Time  `json:"created_at"`
	ExpiresAt  *time.Time `json:"expires_at,omitempty"`
}