package cabana

import (
	"context"
	"log/slog"
	"net/http"
	"strconv"
	"strings"
	"time"

	"git.golem15.com/golem15/summercms/modules/phrasebook"
)

// AdminAPITokenScope is one scope on a token or in the picker list.
type AdminAPITokenScope struct {
	Name        string `json:"name"`
	Label       string `json:"label"`
	Description string `json:"description"`
	ReadOnly    bool   `json:"read_only"`
	Known       bool   `json:"known"`
}

// AdminAPIToken is one personal API token row in list/revoke responses.
type AdminAPIToken struct {
	ID         uint                 `json:"id"`
	Name       string               `json:"name"`
	Hint       string               `json:"hint"`
	Scopes     []AdminAPITokenScope `json:"scopes"`
	CreatedAt  time.Time            `json:"created_at"`
	LastUsedAt *time.Time           `json:"last_used_at"`
	ExpiresAt  *time.Time           `json:"expires_at"`
	RevokedAt  *time.Time           `json:"revoked_at"`
	Expired    bool                 `json:"expired"`
}

// AdminAPITokenCreated is the create response: every AdminAPIToken field plus
// the plaintext token (shown exactly once).
type AdminAPITokenCreated struct {
	AdminAPIToken
	Token string `json:"token"`
}

// AdminAPITokenRequest is the POST /account/tokens body.
type AdminAPITokenRequest struct {
	Name    string   `json:"name"`
	Expires string   `json:"expires"`
	Scopes  []string `json:"scopes"`
}

var allowedTokenCreateKeys = map[string]bool{"name": true, "expires": true, "scopes": true}

func (s *service) accountTokensList(w http.ResponseWriter, r *http.Request) {
	principal := accountPrincipal(w, r)
	if principal == nil {
		return
	}
	db, err := s.db()
	if err != nil {
		slog.Default().ErrorContext(r.Context(), "cabana: account tokens list without a database", "error", err)
		WriteError(w, http.StatusInternalServerError, "error", msgServerError)
		return
	}
	showRevoked := false
	switch strings.ToLower(strings.TrimSpace(r.URL.Query().Get("revoked"))) {
	case "1", "true":
		showRevoked = true
	}
	q := db.WithContext(r.Context()).Where("backend_user_id = ?", principal.ID)
	if !showRevoked {
		q = q.Where("revoked_at IS NULL")
	}
	var rows []BackendAPIToken
	if err := q.Order("created_at DESC").Order("id DESC").Find(&rows).Error; err != nil {
		slog.Default().ErrorContext(r.Context(), "cabana: account tokens list", "error", err)
		WriteError(w, http.StatusInternalServerError, "error", msgServerError)
		return
	}
	tr := s.translator()
	now := time.Now().UTC()
	out := make([]AdminAPIToken, 0, len(rows))
	for i := range rows {
		out = append(out, mapAdminAPIToken(r.Context(), tr, s.reg, &rows[i], now))
	}
	WriteData(w, http.StatusOK, out, nil)
}

func (s *service) accountTokenCreate(w http.ResponseWriter, r *http.Request) {
	principal := accountPrincipal(w, r)
	if principal == nil {
		return
	}
	body, err := s.decodeCappedObject(w, r)
	if err != nil {
		writeRelationError(w, err)
		return
	}
	tr := s.translator()
	if details := refusedTokenCreateKeys(r.Context(), tr, body); len(details) > 0 {
		writeCRUDError(w, &ValidationError{Details: details})
		return
	}
	name, _ := body["name"].(string)
	expires, _ := body["expires"].(string)
	var scopes []string
	switch v := body["scopes"].(type) {
	case []any:
		for _, item := range v {
			if s, ok := item.(string); ok {
				scopes = append(scopes, s)
			}
		}
	case []string:
		scopes = v
	}
	db, err := s.db()
	if err != nil {
		slog.Default().ErrorContext(r.Context(), "cabana: account token create without a database", "error", err)
		WriteError(w, http.StatusInternalServerError, "error", msgServerError)
		return
	}
	now := time.Now().UTC()
	plain, row, details, err := issueAPIToken(db, s.reg, principal, name, expires, scopes, now, false)
	if err != nil {
		slog.Default().ErrorContext(r.Context(), "cabana: account token create", "error", err)
		WriteError(w, http.StatusInternalServerError, "error", msgServerError)
		return
	}
	if details != nil {
		writeCRUDError(w, &ValidationError{Details: translateTokenDetails(r.Context(), tr, details)})
		return
	}
	created := AdminAPITokenCreated{
		AdminAPIToken: mapAdminAPIToken(r.Context(), tr, s.reg, row, now),
		Token:         plain,
	}
	WriteData(w, http.StatusCreated, created, nil)
}

func (s *service) accountTokenRevoke(w http.ResponseWriter, r *http.Request) {
	principal := accountPrincipal(w, r)
	if principal == nil {
		return
	}
	id, err := strconv.ParseUint(r.PathValue("id"), 10, 64)
	if err != nil || id == 0 {
		WriteError(w, http.StatusNotFound, "not_found", msgNotFound)
		return
	}
	db, err := s.db()
	if err != nil {
		slog.Default().ErrorContext(r.Context(), "cabana: account token revoke without a database", "error", err)
		WriteError(w, http.StatusInternalServerError, "error", msgServerError)
		return
	}
	revokedBy := principal.ID
	row, notFound, err := revokeAPIToken(db, principal.ID, uint(id), &revokedBy)
	if err != nil {
		slog.Default().ErrorContext(r.Context(), "cabana: account token revoke", "error", err)
		WriteError(w, http.StatusInternalServerError, "error", msgServerError)
		return
	}
	if notFound {
		WriteError(w, http.StatusNotFound, "not_found", msgNotFound)
		return
	}
	WriteData(w, http.StatusOK, mapAdminAPIToken(r.Context(), s.translator(), s.reg, row, time.Now().UTC()), nil)
}

func (s *service) accountTokenScopes(w http.ResponseWriter, r *http.Request) {
	principal := accountPrincipal(w, r)
	if principal == nil {
		return
	}
	tr := s.translator()
	var out []AdminAPITokenScope
	if s.reg != nil && s.reg.tokenScopes != nil {
		for _, scope := range s.reg.tokenScopes.ordered {
			if !scopeOverlaps(s.reg, principal, scope.Name) {
				continue
			}
			out = append(out, mapCompiledScope(r.Context(), tr, scope))
		}
	}
	WriteData(w, http.StatusOK, out, nil)
}

func refusedTokenCreateKeys(ctx context.Context, tr *phrasebook.Translator, body map[string]any) map[string]any {
	details := map[string]any{}
	for key := range body {
		if !allowedTokenCreateKeys[key] {
			details[key] = []string{backendMessage(ctx, tr, "myaccount.field_not_editable", "This field cannot be changed.")}
		}
	}
	return details
}

func translateTokenDetails(ctx context.Context, tr *phrasebook.Translator, details map[string]any) map[string]any {
	out := map[string]any{}
	for field, raw := range details {
		keys, _ := raw.([]string)
		msgs := make([]string, 0, len(keys))
		for _, key := range keys {
			if name, ok := strings.CutPrefix(key, "api_tokens.scope_unavailable|"); ok {
				msgs = append(msgs, backendMessageParams(ctx, tr, "api_tokens.scope_unavailable", "The scope :name is not available to you.", map[string]string{"name": name}))
				continue
			}
			switch key {
			case "api_tokens.name_required":
				msgs = append(msgs, backendMessage(ctx, tr, key, "Enter a name for the token."))
			case "api_tokens.name_too_long":
				msgs = append(msgs, backendMessage(ctx, tr, key, "The name may have at most 100 characters."))
			case "api_tokens.expires_invalid":
				msgs = append(msgs, backendMessage(ctx, tr, key, "Choose a valid expiry."))
			case "api_tokens.scopes_required":
				msgs = append(msgs, backendMessage(ctx, tr, key, "Choose at least one scope."))
			default:
				msgs = append(msgs, backendMessage(ctx, tr, key, key))
			}
		}
		out[field] = msgs
	}
	return out
}

func backendMessageParams(ctx context.Context, tr *phrasebook.Translator, key, fallback string, params map[string]string) string {
	full := "backend::lang." + key
	if tr != nil && tr.Has(full) {
		if s := tr.Get(ctx, full, params); s != "" && s != full {
			return s
		}
	}
	msg := fallback
	for k, v := range params {
		msg = strings.ReplaceAll(msg, ":"+k, v)
	}
	return msg
}

func mapAdminAPIToken(ctx context.Context, tr *phrasebook.Translator, reg *Registry, row *BackendAPIToken, now time.Time) AdminAPIToken {
	stored := []string{}
	if row.Scopes.Valid {
		stored = row.Scopes.Get()
	}
	scopes := make([]AdminAPITokenScope, 0, len(stored))
	for _, name := range stored {
		scopes = append(scopes, mapStoredScope(ctx, tr, reg, name))
	}
	expired := row.ExpiresAt != nil && !row.ExpiresAt.After(now) && row.RevokedAt == nil
	return AdminAPIToken{
		ID:         row.ID,
		Name:       row.Name,
		Hint:       row.TokenHint,
		Scopes:     scopes,
		CreatedAt:  row.CreatedAt,
		LastUsedAt: row.LastUsedAt,
		ExpiresAt:  row.ExpiresAt,
		RevokedAt:  row.RevokedAt,
		Expired:    expired,
	}
}

func mapStoredScope(ctx context.Context, tr *phrasebook.Translator, reg *Registry, name string) AdminAPITokenScope {
	if reg != nil && reg.tokenScopes != nil {
		if scope, ok := reg.tokenScopes.byName[name]; ok {
			return mapCompiledScope(ctx, tr, scope)
		}
	}
	return AdminAPITokenScope{Name: name, Label: name, Description: "", ReadOnly: false, Known: false}
}

func mapCompiledScope(ctx context.Context, tr *phrasebook.Translator, scope *compiledTokenScope) AdminAPITokenScope {
	label := scope.Label
	desc := scope.Description
	if strings.Contains(label, "::") {
		label = resolveScopePhrase(ctx, tr, label, label)
	}
	if strings.Contains(desc, "::") {
		desc = resolveScopePhrase(ctx, tr, desc, desc)
	}
	readOnly := true
	for m := range scope.Methods {
		if m != "GET" && m != "HEAD" {
			readOnly = false
			break
		}
	}
	if scope.Full && scope.Name == scopeAll {
		readOnly = false
	}
	return AdminAPITokenScope{
		Name:        scope.Name,
		Label:       label,
		Description: desc,
		ReadOnly:    readOnly,
		Known:       true,
	}
}

func resolveScopePhrase(ctx context.Context, tr *phrasebook.Translator, key, fallback string) string {
	if tr != nil && tr.Has(key) {
		if s := tr.Get(ctx, key, nil); s != "" && s != key {
			return s
		}
	}
	return fallback
}