package store

import (
	"context"
	"errors"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgtype"

	"github.com/vasyakrg/dns-autoresolver/internal/provider"
	"github.com/vasyakrg/dns-autoresolver/internal/store/db"
	"github.com/vasyakrg/dns-autoresolver/internal/store/dto"
)

// Account/Template/Domain are provider-neutral domain structs returned by the
// thin wrappers below, so callers (internal/api) never need to import
// internal/store/db directly.

type Account struct {
	ID        uuid.UUID
	ProjectID uuid.UUID
	Provider  string
	SecretEnc string
	Comment   string
}

func accountFromDB(a db.ProviderAccount) Account {
	return Account{ID: a.ID, ProjectID: a.ProjectID, Provider: a.Provider, SecretEnc: a.SecretEnc, Comment: a.Comment}
}

func (s *Store) CreateAccount(ctx context.Context, projectID uuid.UUID, provider, secretEnc, comment string) (Account, error) {
	a, err := s.q.CreateAccount(ctx, db.CreateAccountParams{
		ID: uuid.New(), ProjectID: projectID, Provider: provider, SecretEnc: secretEnc, Comment: comment,
	})
	if err != nil {
		return Account{}, err
	}
	return accountFromDB(a), nil
}

func (s *Store) ListAccounts(ctx context.Context, projectID uuid.UUID) ([]Account, error) {
	rows, err := s.q.ListAccounts(ctx, projectID)
	if err != nil {
		return nil, err
	}
	out := make([]Account, 0, len(rows))
	for _, r := range rows {
		out = append(out, accountFromDB(r))
	}
	return out, nil
}

func (s *Store) GetAccount(ctx context.Context, id, projectID uuid.UUID) (Account, error) {
	a, err := s.q.GetAccount(ctx, db.GetAccountParams{ID: id, ProjectID: projectID})
	if err != nil {
		return Account{}, err
	}
	return accountFromDB(a), nil
}

func (s *Store) DeleteAccount(ctx context.Context, id, projectID uuid.UUID) error {
	return s.q.DeleteAccount(ctx, db.DeleteAccountParams{ID: id, ProjectID: projectID})
}

type Template struct {
	ID        uuid.UUID
	ProjectID uuid.UUID
	Name      string
	Doc       dto.TemplateDoc
	Version   int32
}

func templateFromDB(t db.Template) Template {
	var doc dto.TemplateDoc
	if t.Doc != nil {
		doc = *t.Doc
	}
	return Template{ID: t.ID, ProjectID: t.ProjectID, Name: t.Name, Doc: doc, Version: t.Version}
}

func (s *Store) CreateTemplate(ctx context.Context, projectID uuid.UUID, name string, doc dto.TemplateDoc) (Template, error) {
	d := doc
	t, err := s.q.CreateTemplate(ctx, db.CreateTemplateParams{ID: uuid.New(), ProjectID: projectID, Name: name, Doc: &d})
	if err != nil {
		return Template{}, err
	}
	return templateFromDB(t), nil
}

func (s *Store) ListTemplates(ctx context.Context, projectID uuid.UUID) ([]Template, error) {
	rows, err := s.q.ListTemplates(ctx, projectID)
	if err != nil {
		return nil, err
	}
	out := make([]Template, 0, len(rows))
	for _, r := range rows {
		out = append(out, templateFromDB(r))
	}
	return out, nil
}

func (s *Store) UpdateTemplate(ctx context.Context, id, projectID uuid.UUID, name string, doc dto.TemplateDoc) (Template, error) {
	d := doc
	t, err := s.q.UpdateTemplate(ctx, db.UpdateTemplateParams{ID: id, ProjectID: projectID, Name: name, Doc: &d})
	if err != nil {
		return Template{}, err
	}
	return templateFromDB(t), nil
}

func (s *Store) DeleteTemplate(ctx context.Context, id, projectID uuid.UUID) error {
	return s.q.DeleteTemplate(ctx, db.DeleteTemplateParams{ID: id, ProjectID: projectID})
}

// GetTemplate is a scoped lookup used to verify a template belongs to
// projectID before it is referenced elsewhere (e.g. CreateDomain).
func (s *Store) GetTemplate(ctx context.Context, id, projectID uuid.UUID) (Template, error) {
	t, err := s.q.GetTemplate(ctx, db.GetTemplateParams{ID: id, ProjectID: projectID})
	if err != nil {
		return Template{}, err
	}
	return templateFromDB(t), nil
}

type Domain struct {
	ID                uuid.UUID
	ProjectID         uuid.UUID
	ProviderAccountID uuid.UUID
	ZoneName          string
	ZoneID            string
	TemplateID        *uuid.UUID
}

func domainFromDB(d db.Domain) Domain {
	return Domain{
		ID: d.ID, ProjectID: d.ProjectID, ProviderAccountID: d.ProviderAccountID,
		ZoneName: d.ZoneName, ZoneID: d.ZoneID, TemplateID: d.TemplateID,
	}
}

func (s *Store) CreateDomain(ctx context.Context, projectID, accountID uuid.UUID, zoneName, zoneID string, templateID *uuid.UUID) (Domain, error) {
	d, err := s.q.CreateDomain(ctx, db.CreateDomainParams{
		ID: uuid.New(), ProjectID: projectID, ProviderAccountID: accountID,
		ZoneName: zoneName, ZoneID: zoneID, TemplateID: templateID,
	})
	if err != nil {
		return Domain{}, err
	}
	return domainFromDB(d), nil
}

func (s *Store) ListDomains(ctx context.Context, projectID uuid.UUID) ([]Domain, error) {
	rows, err := s.q.ListDomains(ctx, projectID)
	if err != nil {
		return nil, err
	}
	out := make([]Domain, 0, len(rows))
	for _, r := range rows {
		out = append(out, domainFromDB(r))
	}
	return out, nil
}

func (s *Store) DeleteDomain(ctx context.Context, id, projectID uuid.UUID) error {
	return s.q.DeleteDomain(ctx, db.DeleteDomainParams{ID: id, ProjectID: projectID})
}

// ImportDomains creates one domain per zone inside a single transaction: if
// any zone fails to be created, the whole batch is rolled back so callers
// never observe a partially-imported set of domains.
//
// Import is idempotent: zones that already have a domain for this project
// (enforced by the domains_project_zone_uniq constraint) are silently
// skipped via ON CONFLICT DO NOTHING rather than erroring or duplicating —
// so a repeated POST .../import never creates duplicate domains. Only the
// zones that were actually newly created are returned.
func (s *Store) ImportDomains(ctx context.Context, projectID, accountID uuid.UUID, zones []provider.Zone) ([]Domain, error) {
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx) // no-op once Commit has succeeded

	q := s.q.WithTx(tx)
	out := make([]Domain, 0, len(zones))
	for _, z := range zones {
		d, err := q.ImportDomain(ctx, db.ImportDomainParams{
			ID: uuid.New(), ProjectID: projectID, ProviderAccountID: accountID,
			ZoneName: z.Name, ZoneID: z.ID, TemplateID: nil,
		})
		if err != nil {
			if errors.Is(err, pgx.ErrNoRows) {
				// ON CONFLICT DO NOTHING: this zone was already imported
				// for this project — skip it rather than fail the batch.
				continue
			}
			return nil, err
		}
		out = append(out, domainFromDB(d))
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}
	return out, nil
}

// SetDomainTemplate attaches (or clears, when templateID is nil) the DNS
// template used to check/apply a domain. When templateID is non-nil it must
// belong to the same project — verified via scoped GetTemplate — otherwise
// a caller could bind a domain to another tenant's template.
func (s *Store) SetDomainTemplate(ctx context.Context, domainID, projectID uuid.UUID, templateID *uuid.UUID) (Domain, error) {
	if templateID != nil {
		if _, err := s.GetTemplate(ctx, *templateID, projectID); err != nil {
			return Domain{}, err
		}
	}
	d, err := s.q.UpdateDomainTemplate(ctx, db.UpdateDomainTemplateParams{
		ID: domainID, ProjectID: projectID, TemplateID: templateID,
	})
	if err != nil {
		return Domain{}, err
	}
	return domainFromDB(d), nil
}

// User and Project are provider-neutral domain structs for the auth/tenant
// layer (Фаза 2), mirroring the Account/Template/Domain wrappers above so
// callers never need to import internal/store/db directly.

type User struct {
	ID           uuid.UUID
	Email        string
	PasswordHash string
}

type Project struct {
	ID     uuid.UUID
	UserID uuid.UUID
	Name   string
}

// ptr is a small helper for passing a Go string into a nullable text column
// (password_hash) via sqlc's generated *string param type.
func ptr(s string) *string { return &s }

// strFromPtr converts a nullable text column back into a plain string; a
// nil password_hash never happens on the real registration flow (an argon2
// hash is always supplied), but is handled defensively here.
func strFromPtr(p *string) string {
	if p == nil {
		return ""
	}
	return *p
}

func toUser(u db.User) User {
	return User{ID: u.ID, Email: u.Email, PasswordHash: strFromPtr(u.PasswordHash)}
}

func toProject(p db.Project) Project {
	return Project{ID: p.ID, UserID: p.UserID, Name: p.Name}
}

func (s *Store) CreateUser(ctx context.Context, email, passwordHash string) (User, error) {
	u, err := s.q.CreateUser(ctx, db.CreateUserParams{ID: uuid.New(), Email: email, PasswordHash: ptr(passwordHash)})
	if err != nil {
		return User{}, err
	}
	return toUser(u), nil
}

func (s *Store) GetUserByEmail(ctx context.Context, email string) (User, error) {
	u, err := s.q.GetUserByEmail(ctx, email)
	if err != nil {
		return User{}, err
	}
	return toUser(u), nil
}

func (s *Store) CreateProjectForUser(ctx context.Context, userID uuid.UUID, name string) (Project, error) {
	p, err := s.q.CreateProject(ctx, db.CreateProjectParams{ID: uuid.New(), UserID: userID, Name: name})
	if err != nil {
		return Project{}, err
	}
	return toProject(p), nil
}

func (s *Store) GetProjectOwned(ctx context.Context, projectID, userID uuid.UUID) (Project, error) {
	p, err := s.q.GetProjectOwned(ctx, db.GetProjectOwnedParams{ID: projectID, UserID: userID})
	if err != nil {
		return Project{}, err
	}
	return toProject(p), nil
}

func (s *Store) GetUserProject(ctx context.Context, userID uuid.UUID) (Project, error) {
	p, err := s.q.GetUserProject(ctx, userID)
	if err != nil {
		return Project{}, err
	}
	return toProject(p), nil
}

func (s *Store) CreateSession(ctx context.Context, userID uuid.UUID, tokenHash string, expiresAt time.Time) error {
	return s.q.CreateSession(ctx, db.CreateSessionParams{
		ID:        uuid.New(),
		UserID:    userID,
		TokenHash: tokenHash,
		ExpiresAt: pgtype.Timestamptz{Time: expiresAt, Valid: true},
	})
}

// GetSessionUser returns the owning user ID for a non-expired session token;
// expired sessions are excluded by the query itself (expires_at > now()).
func (s *Store) GetSessionUser(ctx context.Context, tokenHash string) (uuid.UUID, error) {
	return s.q.GetSessionUser(ctx, tokenHash)
}

func (s *Store) DeleteSession(ctx context.Context, tokenHash string) error {
	return s.q.DeleteSession(ctx, tokenHash)
}

// RegisterUser creates a user and their default project in one transaction,
// mirroring the ImportDomains pattern above: if project creation fails, the
// user insert is rolled back too, so a caller never observes a user without
// a default project.
func (s *Store) RegisterUser(ctx context.Context, email, passwordHash string) (User, Project, error) {
	tx, err := s.pool.Begin(ctx)
	if err != nil {
		return User{}, Project{}, err
	}
	defer tx.Rollback(ctx) // no-op once Commit has succeeded

	q := s.q.WithTx(tx)
	uid := uuid.New()
	dbu, err := q.CreateUser(ctx, db.CreateUserParams{ID: uid, Email: email, PasswordHash: ptr(passwordHash)})
	if err != nil {
		return User{}, Project{}, err
	}
	dbp, err := q.CreateProject(ctx, db.CreateProjectParams{ID: uuid.New(), UserID: uid, Name: "default"})
	if err != nil {
		return User{}, Project{}, err
	}
	if err := tx.Commit(ctx); err != nil {
		return User{}, Project{}, err
	}
	return toUser(dbu), toProject(dbp), nil
}