package main

import (
	"context"
	"crypto/subtle"
	"encoding/json"
	"errors"
	"net/http"
	"strings"

	"git.cin.su/m/Assistant/adapters/postgres"
	"git.cin.su/m/Assistant/contracts/continuity"
	continuitydomain "git.cin.su/m/Assistant/modules/continuity/domain"
)

type continuityExecutorRepository interface {
	SatisfyDelivered(context.Context, continuity.SatisfyDeliveredCommand) (continuity.ActionReceipt, error)
	LoadActionReceipt(context.Context, continuity.CommittedActionIntentID) (continuity.ActionReceipt, error)
}

func registerInternalExecutorRoutes(mux *http.ServeMux, repository continuityExecutorRepository, token string) {
	mux.HandleFunc("POST /v1/internal/executor/satisfy-delivered", requireExecutorToken(token, func(w http.ResponseWriter, r *http.Request) {
		var command continuity.SatisfyDeliveredCommand
		decoder := json.NewDecoder(http.MaxBytesReader(w, r.Body, 32<<10))
		if err := decoder.Decode(&command); err != nil {
			http.Error(w, "invalid executor command", http.StatusBadRequest)
			return
		}
		receipt, err := repository.SatisfyDelivered(r.Context(), command)
		switch {
		case err == nil:
			w.Header().Set("Content-Type", "application/json")
			_ = json.NewEncoder(w).Encode(receipt)
		case errors.Is(err, continuitydomain.ErrInvalidSatisfaction):
			http.Error(w, "invalid executor command", http.StatusBadRequest)
		case errors.Is(err, postgres.ErrProspectiveNotFound):
			http.Error(w, "prospective item not found", http.StatusNotFound)
		case errors.Is(err, postgres.ErrProspectiveOwnerConflict), errors.Is(err, postgres.ErrProspectiveStateConflict),
			errors.Is(err, postgres.ErrProspectiveRevisionConflict), errors.Is(err, postgres.ErrActionIntentConflict):
			http.Error(w, "prospective command conflict", http.StatusConflict)
		default:
			http.Error(w, "continuity execution unavailable", http.StatusInternalServerError)
		}
	}))
	mux.HandleFunc("GET /v1/internal/executor/receipts/{intentID}", requireExecutorToken(token, func(w http.ResponseWriter, r *http.Request) {
		receipt, err := repository.LoadActionReceipt(r.Context(), continuity.CommittedActionIntentID(r.PathValue("intentID")))
		if errors.Is(err, postgres.ErrActionReceiptNotFound) {
			http.Error(w, "receipt not found", http.StatusNotFound)
			return
		}
		if err != nil {
			http.Error(w, "continuity receipt unavailable", http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(receipt)
	}))
}

func requireExecutorToken(expected string, next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		provided := strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer ")
		if expected == "" || len(provided) != len(expected) || subtle.ConstantTimeCompare([]byte(provided), []byte(expected)) != 1 {
			http.Error(w, "executor denied", http.StatusUnauthorized)
			return
		}
		next(w, r)
	}
}