package keycloak

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"path"
	"strings"
)

// ─── organizations API ───────────────────────────────────────────────────

type orgCreate struct {
	Name        string              `json:"name"`
	Alias       string              `json:"alias"`
	Description string              `json:"description,omitempty"`
	Domains     []map[string]any    `json:"domains,omitempty"`
	Attributes  map[string][]string `json:"attributes,omitempty"`
}

type userCreate struct {
	Username      string              `json:"username"`
	Email         string              `json:"email"`
	FirstName     string              `json:"firstName,omitempty"`
	LastName      string              `json:"lastName,omitempty"`
	Enabled       bool                `json:"enabled"`
	EmailVerified bool                `json:"emailVerified"`
	Attributes    map[string][]string `json:"attributes,omitempty"`
}

// CreateOrgAndInvite creates the organization, creates the IT_ADMIN user,
// adds them as org member, and triggers the verify-email-and-set-password
// flow (Keycloak's native "invite via email" path).
//
// Best-effort atomicity: on partial failure we leave KC in whatever state
// it's in and surface the error. A follow-up reconciler (M4.x or M14.x)
// can heal divergence. For local dev where everything either succeeds or
// the test surfaces the exact failure, this is fine.
func (a *HTTPAdapter) CreateOrgAndInvite(ctx context.Context, in InviteInput) (*InviteResult, error) {
	if in.AdminEmail == "" {
		return nil, fmt.Errorf("keycloak: admin email required")
	}

	// 1. Create org with tenant_id baked in as an attribute so we can
	//    correlate the two systems with a single Admin API call later.
	orgPayload := orgCreate{
		Name:        in.Name,
		Alias:       in.Slug,
		Description: fmt.Sprintf("Auto-provisioned from tenant-registry %s", in.TenantID),
		Attributes: map[string][]string{
			"tenant_id": {in.TenantID},
		},
	}
	resp, err := a.adminCall(ctx, http.MethodPost, "/organizations", orgPayload, nil)
	if err != nil {
		return nil, err
	}
	switch resp.StatusCode {
	case http.StatusCreated:
		// keep going
	case http.StatusConflict:
		_ = resp.Body.Close()
		return nil, fmt.Errorf("%w: alias=%s", ErrOrgConflict, in.Slug)
	default:
		body, _ := io.ReadAll(resp.Body)
		_ = resp.Body.Close()
		return nil, fmt.Errorf("create org: %d %s", resp.StatusCode, body)
	}
	// Keycloak returns the id in the Location header.
	orgID := lastSegment(resp.Header.Get("Location"))
	_ = resp.Body.Close()
	if orgID == "" {
		// Fallback: query by alias.
		orgID, err = a.findOrgByAlias(ctx, in.Slug)
		if err != nil {
			return nil, fmt.Errorf("create org: missing Location and lookup failed: %w", err)
		}
	}

	// 2. Create the user (disabled until they set a password).
	first, last := splitName(in.AdminName)
	userPayload := userCreate{
		Username:      in.AdminEmail,
		Email:         in.AdminEmail,
		FirstName:     first,
		LastName:      last,
		Enabled:       true,
		EmailVerified: false,
		Attributes: map[string][]string{
			"tenant_id":     {in.TenantID},
			"tenant_slug":   {in.Slug},
			"org_roles":     {"IT_ADMIN"},
			"tenant_status": {"trial"},
		},
	}
	resp, err = a.adminCall(ctx, http.MethodPost, "/users", userPayload, nil)
	if err != nil {
		return nil, fmt.Errorf("create user: %w", err)
	}
	switch resp.StatusCode {
	case http.StatusCreated:
		// keep going
	case http.StatusConflict:
		_ = resp.Body.Close()
		return nil, fmt.Errorf("%w: email=%s", ErrUserConflict, in.AdminEmail)
	default:
		body, _ := io.ReadAll(resp.Body)
		_ = resp.Body.Close()
		return nil, fmt.Errorf("create user: %d %s", resp.StatusCode, body)
	}
	userID := lastSegment(resp.Header.Get("Location"))
	_ = resp.Body.Close()
	if userID == "" {
		userID, err = a.findUserByEmail(ctx, in.AdminEmail)
		if err != nil {
			return nil, fmt.Errorf("create user: missing Location and lookup failed: %w", err)
		}
	}

	// 3. Add user to organization (member).
	addBody := map[string]string{"id": userID}
	resp, err = a.adminCall(ctx, http.MethodPost,
		fmt.Sprintf("/organizations/%s/members", orgID), addBody, nil)
	if err != nil {
		return nil, fmt.Errorf("add member: %w", err)
	}
	if resp.StatusCode/100 != 2 && resp.StatusCode != http.StatusConflict {
		body, _ := io.ReadAll(resp.Body)
		_ = resp.Body.Close()
		return nil, fmt.Errorf("add member: %d %s", resp.StatusCode, body)
	}
	_ = resp.Body.Close()

	// 4. Trigger the verify-email + set-password execute-actions email.
	//    In dev (no Stalwart) we also surface the action-token URL to
	//    the caller so they can hit it directly.
	inviteURL, err := a.executeActionsEmail(ctx, userID,
		[]string{"VERIFY_EMAIL", "UPDATE_PASSWORD"},
		"https://breakpilot.com/onboard")
	if err != nil {
		// Non-fatal — admin can resend from the KC UI.
		return &InviteResult{OrganizationID: orgID, UserID: userID, InviteURL: ""}, nil
	}

	return &InviteResult{OrganizationID: orgID, UserID: userID, InviteURL: inviteURL}, nil
}

// SyncClaims pushes the up-to-date claim bundle into the user's KC
// attributes. Called by tenant-registry whenever entitlements change.
func (a *HTTPAdapter) SyncClaims(ctx context.Context, userID string, c Claims) error {
	attrs := map[string][]string{
		"tenant_id":     {c.TenantID},
		"tenant_slug":   {c.TenantSlug},
		"org_roles":     c.OrgRoles,
		"products":      c.Products,
		"plan":          {c.Plan},
		"tenant_status": {c.TenantStatus},
	}
	resp, err := a.adminCall(ctx, http.MethodPut, "/users/"+userID,
		map[string]any{"attributes": attrs}, nil)
	if err != nil {
		return err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode/100 != 2 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("sync claims: %d %s", resp.StatusCode, body)
	}
	return nil
}

// ─── helpers ─────────────────────────────────────────────────────────────

func (a *HTTPAdapter) findOrgByAlias(ctx context.Context, alias string) (string, error) {
	resp, err := a.adminCall(ctx, http.MethodGet,
		fmt.Sprintf("/organizations?search=%s&exact=true", alias), nil, nil)
	if err != nil {
		return "", err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode/100 != 2 {
		return "", fmt.Errorf("find org: %d", resp.StatusCode)
	}
	var orgs []struct {
		ID    string `json:"id"`
		Alias string `json:"alias"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&orgs); err != nil {
		return "", err
	}
	for _, o := range orgs {
		if o.Alias == alias {
			return o.ID, nil
		}
	}
	return "", errors.New("org not found")
}

func (a *HTTPAdapter) findUserByEmail(ctx context.Context, email string) (string, error) {
	resp, err := a.adminCall(ctx, http.MethodGet,
		fmt.Sprintf("/users?email=%s&exact=true", email), nil, nil)
	if err != nil {
		return "", err
	}
	defer func() { _ = resp.Body.Close() }()
	var users []struct {
		ID    string `json:"id"`
		Email string `json:"email"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&users); err != nil {
		return "", err
	}
	for _, u := range users {
		if strings.EqualFold(u.Email, email) {
			return u.ID, nil
		}
	}
	return "", errors.New("user not found")
}

func (a *HTTPAdapter) executeActionsEmail(ctx context.Context, userID string, actions []string, redirectURI string) (string, error) {
	resp, err := a.adminCall(ctx, http.MethodPut,
		fmt.Sprintf("/users/%s/execute-actions-email?client_id=dev-portal&redirect_uri=%s", userID, redirectURI),
		actions, nil)
	if err != nil {
		return "", err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode/100 != 2 {
		return "", fmt.Errorf("execute-actions: %d", resp.StatusCode)
	}
	// KC doesn't return the action-token URL via this endpoint — it sends
	// the email. For dev we surface an admin-portal pointer so the tester
	// has somewhere to land.
	return fmt.Sprintf("%s/realms/%s/account", a.cfg.BaseURL, a.cfg.Realm), nil
}

func lastSegment(loc string) string {
	if loc == "" {
		return ""
	}
	return path.Base(loc)
}

func splitName(full string) (first, last string) {
	full = strings.TrimSpace(full)
	if full == "" {
		return "", ""
	}
	parts := strings.Fields(full)
	if len(parts) == 1 {
		return parts[0], ""
	}
	return parts[0], strings.Join(parts[1:], " ")
}