package httpapi

import (
	"context"
	"net/http"
	"strings"
)

type ctxKey int

const authCtxKey ctxKey = 1

// Auth holds resolved API identity for a request.
type Auth struct {
	TenantID string
	Role     string // viewer, editor, operator, node
	Token    string
	APIKeyID string // non-empty for DB-managed keys
}

func authFromContext(ctx context.Context) (Auth, bool) {
	a, ok := ctx.Value(authCtxKey).(Auth)
	return a, ok
}

type apiKeyRecord struct {
	token    string
	tenantID string
	role     string
	keyID    string // set for DB-managed keys (last_used_at)
}

func parseAPIKeysSpec(spec string) []apiKeyRecord {
	spec = strings.TrimSpace(spec)
	if spec == "" {
		return nil
	}
	var out []apiKeyRecord
	for _, part := range strings.Split(spec, ",") {
		part = strings.TrimSpace(part)
		if part == "" {
			continue
		}
		fields := strings.Split(part, "|")
		if len(fields) != 3 {
			continue
		}
		out = append(out, apiKeyRecord{
			token:    strings.TrimSpace(fields[0]),
			tenantID: strings.TrimSpace(fields[1]),
			role:     strings.TrimSpace(fields[2]),
		})
	}
	return out
}

func (s *Server) authMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		h := r.Header.Get("Authorization")
		const p = "Bearer "
		if !strings.HasPrefix(h, p) {
			writeProblem(w, http.StatusUnauthorized, "Unauthorized", "missing or invalid bearer token")
			return
		}
		raw := strings.TrimSpace(strings.TrimPrefix(h, p))
		if raw == "dev" {
			if a, ok := s.devAuth(); ok {
				r = r.WithContext(context.WithValue(r.Context(), authCtxKey, a))
				next.ServeHTTP(w, r)
				return
			}
		}
		matched, ok := s.keyResolver.Lookup(raw)
		if !ok {
			writeProblem(w, http.StatusUnauthorized, "Unauthorized", "unknown api key")
			return
		}
		a := Auth{TenantID: matched.tenantID, Role: matched.role, Token: raw, APIKeyID: matched.keyID}
		if matched.keyID != "" {
			go func(id string) { _ = s.store.TouchAPIKeyLastUsed(id) }(matched.keyID)
		}
		r = r.WithContext(context.WithValue(r.Context(), authCtxKey, a))
		next.ServeHTTP(w, r)
	})
}

func (s *Server) devAuth() (Auth, bool) {
	tid, _, _, _, _ := s.store.DemoIDs()
	if tid == "" {
		return Auth{}, false
	}
	return Auth{TenantID: tid, Role: "operator", Token: "dev"}, true
}

func roleLevel(role string) int {
	switch strings.ToLower(role) {
	case "viewer":
		return 1
	case "editor":
		return 2
	case "operator":
		return 3
	default:
		return 0
	}
}

// requireAtLeast rejects node role and enforces viewer/editor/operator ladder.
func (s *Server) requireAtLeast(w http.ResponseWriter, a Auth, need string) bool {
	if strings.ToLower(a.Role) == "node" {
		writeProblem(w, http.StatusForbidden, "Forbidden", "node role cannot access this resource")
		return false
	}
	if roleLevel(a.Role) < roleLevel(need) {
		writeProblem(w, http.StatusForbidden, "Forbidden", "insufficient role")
		return false
	}
	return true
}

func (s *Server) requireNode(w http.ResponseWriter, a Auth) bool {
	if strings.ToLower(a.Role) != "node" {
		writeProblem(w, http.StatusForbidden, "Forbidden", "node role required")
		return false
	}
	return true
}