// Package httpapi exposes the Control API's HTTP surface — the only way
// validator-agents, probers, and operators interact with the system. All
// business logic lives in internal/orchestrator; handlers here do request
// parsing/validation, call into the orchestrator or db package, and shape
// the JSON response.
package httpapi

import (
	"encoding/json"
	"errors"
	"log/slog"
	"net/http"

	"cloudipvalidator/internal/db"
	"cloudipvalidator/internal/orchestrator"
)

type Server struct {
	DB   *db.DB
	Orch *orchestrator.Orchestrator
	Log  *slog.Logger
	Auth Authenticator
}

func New(d *db.DB, o *orchestrator.Orchestrator, log *slog.Logger) *Server {
	return &Server{DB: d, Orch: o, Log: log}
}

func (s *Server) Handler() http.Handler {
	s.Auth.Log = s.Log
	mux := http.NewServeMux()
	s.routes(mux)
	return loggingMiddleware(s.Log, mux)
}

func loggingMiddleware(log *slog.Logger, next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		next.ServeHTTP(w, r)
		log.Debug("request", "method", r.Method, "path", r.URL.Path, "remote", r.RemoteAddr)
	})
}

func writeJSON(w http.ResponseWriter, status int, v interface{}) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if v != nil {
		_ = json.NewEncoder(w).Encode(v)
	}
}

func writeError(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, errorResponse{Error: msg})
}

func readJSON(r *http.Request, v interface{}) error {
	if r.Body == nil || r.ContentLength == 0 {
		return nil
	}
	dec := json.NewDecoder(r.Body)
	return dec.Decode(v)
}

// writeDBError maps the typed sentinel errors returned by internal/db's
// admin mutation methods to the appropriate HTTP status, instead of
// defaulting everything to 500 like the older read-only admin handlers do.
func writeDBError(w http.ResponseWriter, err error) {
	switch {
	case errors.Is(err, db.ErrNotFound):
		writeError(w, http.StatusNotFound, err.Error())
	case errors.Is(err, db.ErrConflict), errors.Is(err, db.ErrBusy), errors.Is(err, db.ErrInUse), errors.Is(err, db.ErrInvalidState):
		writeError(w, http.StatusConflict, err.Error())
	case errors.Is(err, db.ErrValidation):
		writeError(w, http.StatusBadRequest, err.Error())
	default:
		writeError(w, http.StatusInternalServerError, err.Error())
	}
}