package controllers

import (
	"context"
	"net/http"

	"code.crute.us/mcrute/cloud-identity-broker/app/models"

	glecho "code.crute.us/mcrute/golib/echo"
	"code.crute.us/mcrute/golib/echo/controller"
	"github.com/labstack/echo/v4"
)

type APIUserHandler struct {
	Store models.UserStore
}

func (h *APIUserHandler) Register(prefix string, r glecho.URLRouter, mw ...echo.MiddlewareFunc) {
	// This resource did not exist in the V1 API and thus has no V1
	// representation. We use the default handlers for V1 because otherwise
	// requests with V1 Accept headers would result in 406 Unacceptable errors.
	gh := &controller.ContentTypeNegotiatingHandler{
		DefaultHandler: h.HandleGet,
		Handlers: map[string]echo.HandlerFunc{
			contentTypeV1: h.HandleGet,
			contentTypeV2: h.HandleGet,
		},
	}
	r.GET(prefix, gh.Handle, mw...)

	ph := &controller.ContentTypeNegotiatingHandler{
		DefaultHandler: h.HandlePut,
		Handlers: map[string]echo.HandlerFunc{
			contentTypeV1: h.HandlePut,
			contentTypeV2: h.HandlePut,
		},
	}
	r.PUT(prefix, ph.Handle, mw...)

	poh := &controller.ContentTypeNegotiatingHandler{
		DefaultHandler: h.HandlePost,
		Handlers: map[string]echo.HandlerFunc{
			contentTypeV1: h.HandlePost,
			contentTypeV2: h.HandlePost,
		},
	}
	r.POST(prefix, poh.Handle, mw...)

	r.DELETE(prefix, h.HandleDelete, mw...)
}

func (h *APIUserHandler) HandleGet(c echo.Context) error {
	u, err := h.Store.Get(context.Background(), c.Param("user"))
	if err != nil {
		return echo.ErrInternalServerError
	}

	return c.JSON(http.StatusOK, u)
}

func validateKeysAndTokens(in *models.User) error {
	for k, v := range in.Keys {
		if k != v.KeyId {
			return &echo.HTTPError{
				Code:    http.StatusBadRequest,
				Message: "Key ID must match hash key.",
			}
		}

		if v.PrivateKey == nil && v.PublicKey == nil {
			return &echo.HTTPError{
				Code:    http.StatusBadRequest,
				Message: "One of public_key or private_key must be set",
			}
		}

		if v.PrivateKey != nil && v.PublicKey != nil {
			return &echo.HTTPError{
				Code:    http.StatusBadRequest,
				Message: "Only one of public_key or private_key may be set",
			}
		}
	}

	for k, v := range in.AuthTokens {
		if k != v.Kind {
			return &echo.HTTPError{
				Code:    http.StatusBadRequest,
				Message: "Token kind must match hash key.",
			}
		}
	}

	return nil
}

func (h *APIUserHandler) HandlePut(c echo.Context) error {
	var in models.User
	if err := c.Echo().JSONSerializer.Deserialize(c, &in); err != nil {
		return echo.ErrBadRequest
	}

	u, err := h.Store.Get(context.Background(), c.Param("user"))
	if err != nil {
		return echo.ErrInternalServerError
	}

	if in.Username != u.Username {
		return &echo.HTTPError{
			Code:    http.StatusBadRequest,
			Message: "Username can not be changed. Create a new user.",
		}
	}

	if in.Deleted != nil && u.Deleted == nil {
		return &echo.HTTPError{
			Code:    http.StatusBadRequest,
			Message: "Use the DELETE method to delete a record",
		}
	}

	if err := validateKeysAndTokens(&in); err != nil {
		return err
	}

	err = h.Store.Put(context.Background(), &in)
	if err != nil {
		return echo.ErrInternalServerError
	}

	return c.String(http.StatusNoContent, "")
}

func (h *APIUserHandler) HandlePost(c echo.Context) error {
	var in models.User
	if err := c.Echo().JSONSerializer.Deserialize(c, &in); err != nil {
		return echo.ErrBadRequest
	}

	_, err := h.Store.Get(context.Background(), c.Param("user"))
	if err == nil {
		return &echo.HTTPError{
			Code:    http.StatusConflict,
			Message: "User with username already exists.",
		}
	}

	if in.Deleted != nil {
		return &echo.HTTPError{
			Code:    http.StatusBadRequest,
			Message: "Can not create deleted user, set Deleted to null",
		}
	}

	if err := validateKeysAndTokens(&in); err != nil {
		return err
	}

	err = h.Store.Put(context.Background(), &in)
	if err != nil {
		return echo.ErrInternalServerError
	}

	c.Response().Header().Add("Location", glecho.URLFor(c, "/api/user", in.Username).String())

	return c.String(http.StatusCreated, "")
}

func (h *APIUserHandler) HandleDelete(c echo.Context) error {
	u, err := h.Store.Get(context.Background(), c.Param("user"))
	if err != nil {
		return echo.ErrInternalServerError
	}

	err = h.Store.Delete(context.Background(), u)
	if err != nil {
		return echo.ErrInternalServerError
	}

	return c.String(http.StatusNoContent, "")
}