package handler

import (
	"context"
	"errors"
	"io"
	"net/url"

	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/internal/logs"
	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/resolver"
	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/response"
	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/tree"
	"git.frostfs.info/TrueCloudLab/frostfs-http-gw/utils"
	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/pool"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/user"
	"github.com/valyala/fasthttp"
	"go.uber.org/zap"
)

type Config interface {
	DefaultTimestamp() bool
	ZipCompression() bool
	ClientCut() bool
}

type Handler struct {
	log               *zap.Logger
	pool              *pool.Pool
	ownerID           *user.ID
	config            Config
	containerResolver *resolver.ContainerResolver
	tree              *tree.Tree
}

func New(params *utils.AppParams, config Config, tree *tree.Tree) *Handler {
	return &Handler{
		log:               params.Logger,
		pool:              params.Pool,
		ownerID:           params.Owner,
		config:            config,
		containerResolver: params.Resolver,
		tree:              tree,
	}
}

// getContainerID decode container id, if it's not a valid container id
// then trey to resolve name using provided resolver.
func (h *Handler) getContainerID(ctx context.Context, containerID string) (*cid.ID, error) {
	cnrID := new(cid.ID)
	err := cnrID.DecodeString(containerID)
	if err != nil {
		cnrID, err = h.containerResolver.Resolve(ctx, containerID)
	}
	return cnrID, err
}

// byAddress is a wrapper for function (e.g. request.headObject, request.receiveFile) that
// prepares request and object address to it.
func (h *Handler) byAddress(c *fasthttp.RequestCtx, f func(context.Context, request, oid.Address)) {
	var (
		idCnr, _ = c.UserValue("cid").(string)
		idObj, _ = c.UserValue("oid").(string)
		log      = h.log.With(zap.String("cid", idCnr), zap.String("oid", idObj))
	)

	ctx := utils.GetContextFromRequest(c)

	cnrID, err := h.getContainerID(ctx, idCnr)
	if err != nil {
		log.Error(logs.WrongContainerID, zap.Error(err))
		response.Error(c, "wrong container id", fasthttp.StatusBadRequest)
		return
	}

	objID := new(oid.ID)
	if err = objID.DecodeString(idObj); err != nil {
		log.Error(logs.WrongObjectID, zap.Error(err))
		response.Error(c, "wrong object id", fasthttp.StatusBadRequest)
		return
	}

	var addr oid.Address
	addr.SetContainer(*cnrID)
	addr.SetObject(*objID)

	f(ctx, *h.newRequest(c, log), addr)
}

// byBucketname is a wrapper for function (e.g. request.headObject, request.receiveFile) that
// prepares request and object address to it.
func (h *Handler) byBucketname(req *fasthttp.RequestCtx, f func(context.Context, request, oid.Address)) {
	var (
		bucketname = req.UserValue("cid").(string)
		key        = req.UserValue("oid").(string)
		log        = h.log.With(zap.String("bucketname", bucketname), zap.String("key", key))
	)

	ctx := utils.GetContextFromRequest(req)

	cnrID, err := h.getContainerID(ctx, bucketname)
	if err != nil {
		log.Error(logs.WrongContainerID, zap.Error(err))
		response.Error(req, "wrong container id", fasthttp.StatusBadRequest)
		return
	}

	foundOid, err := h.tree.GetLatestVersion(ctx, cnrID, key)
	if err != nil {
		log.Error(logs.ObjectWasntFound, zap.Error(err))
		response.Error(req, "object wasn't found", fasthttp.StatusNotFound)
		return
	}
	if foundOid.DeleteMarker {
		log.Error(logs.ObjectWasDeleted)
		response.Error(req, "object deleted", fasthttp.StatusNotFound)
		return
	}

	var addr oid.Address
	addr.SetContainer(*cnrID)
	addr.SetObject(foundOid.OID)

	f(ctx, *h.newRequest(req, log), addr)
}

// byAttribute is a wrapper similar to byAddress.
func (h *Handler) byAttribute(c *fasthttp.RequestCtx, f func(context.Context, request, oid.Address)) {
	var (
		scid, _ = c.UserValue("cid").(string)
		key, _  = url.QueryUnescape(c.UserValue("attr_key").(string))
		val, _  = url.QueryUnescape(c.UserValue("attr_val").(string))
		log     = h.log.With(zap.String("cid", scid), zap.String("attr_key", key), zap.String("attr_val", val))
	)

	ctx := utils.GetContextFromRequest(c)

	containerID, err := h.getContainerID(ctx, scid)
	if err != nil {
		log.Error(logs.WrongContainerID, zap.Error(err))
		response.Error(c, "wrong container id", fasthttp.StatusBadRequest)
		return
	}

	res, err := h.search(ctx, containerID, key, val, object.MatchStringEqual)
	if err != nil {
		log.Error(logs.CouldNotSearchForObjects, zap.Error(err))
		response.Error(c, "could not search for objects: "+err.Error(), fasthttp.StatusBadRequest)
		return
	}

	defer res.Close()

	buf := make([]oid.ID, 1)

	n, err := res.Read(buf)
	if n == 0 {
		if errors.Is(err, io.EOF) {
			log.Error(logs.ObjectNotFound, zap.Error(err))
			response.Error(c, "object not found", fasthttp.StatusNotFound)
			return
		}

		log.Error(logs.ReadObjectListFailed, zap.Error(err))
		response.Error(c, "read object list failed: "+err.Error(), fasthttp.StatusBadRequest)
		return
	}

	var addrObj oid.Address
	addrObj.SetContainer(*containerID)
	addrObj.SetObject(buf[0])

	f(ctx, *h.newRequest(c, log), addrObj)
}