package oci

import (
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"

	"git.wntrmute.dev/mc/mcr/internal/db"
	"git.wntrmute.dev/mc/mcr/internal/policy"
)

func (h *Handler) handleBlobGet(w http.ResponseWriter, r *http.Request, repo, digest string) {
	if !h.checkPolicy(w, r, policy.ActionPull, repo) {
		return
	}

	repoID, err := h.db.GetRepositoryByName(repo)
	if err != nil {
		if errors.Is(err, db.ErrRepoNotFound) {
			writeOCIError(w, "NAME_UNKNOWN", http.StatusNotFound,
				fmt.Sprintf("repository %q not found", repo))
			return
		}
		h.log.Error("blob get: lookup repository", "error", err, "repo", repo)
		writeOCIError(w, "UNKNOWN", http.StatusInternalServerError, "internal error")
		return
	}

	exists, err := h.db.BlobExistsInRepo(repoID, digest)
	if err != nil {
		h.log.Error("blob get: check blob exists in repo", "error", err, "repo", repo, "digest", digest)
		writeOCIError(w, "UNKNOWN", http.StatusInternalServerError, "internal error")
		return
	}
	if !exists {
		writeOCIError(w, "BLOB_UNKNOWN", http.StatusNotFound,
			fmt.Sprintf("blob %q not found in repository", digest))
		return
	}

	size, err := h.blobs.Stat(digest)
	if err != nil {
		h.log.Error("blob get: stat blob in storage", "error", err, "repo", repo, "digest", digest)
		writeOCIError(w, "BLOB_UNKNOWN", http.StatusNotFound, "blob not found in storage")
		return
	}

	rc, err := h.blobs.Open(digest)
	if err != nil {
		h.log.Error("blob get: open blob in storage", "error", err, "repo", repo, "digest", digest)
		writeOCIError(w, "UNKNOWN", http.StatusInternalServerError, "internal error")
		return
	}
	defer func() { _ = rc.Close() }()

	w.Header().Set("Content-Type", "application/octet-stream")
	w.Header().Set("Docker-Content-Digest", digest)
	w.Header().Set("Content-Length", strconv.FormatInt(size, 10))
	w.WriteHeader(http.StatusOK)
	_, _ = io.Copy(w, rc)
}

func (h *Handler) handleBlobHead(w http.ResponseWriter, r *http.Request, repo, digest string) {
	if !h.checkPolicy(w, r, policy.ActionPull, repo) {
		return
	}

	repoID, err := h.db.GetRepositoryByName(repo)
	if err != nil {
		if errors.Is(err, db.ErrRepoNotFound) {
			writeOCIError(w, "NAME_UNKNOWN", http.StatusNotFound,
				fmt.Sprintf("repository %q not found", repo))
			return
		}
		h.log.Error("blob head: lookup repository", "error", err, "repo", repo)
		writeOCIError(w, "UNKNOWN", http.StatusInternalServerError, "internal error")
		return
	}

	exists, err := h.db.BlobExistsInRepo(repoID, digest)
	if err != nil {
		h.log.Error("blob head: check blob exists in repo", "error", err, "repo", repo, "digest", digest)
		writeOCIError(w, "UNKNOWN", http.StatusInternalServerError, "internal error")
		return
	}
	if !exists {
		writeOCIError(w, "BLOB_UNKNOWN", http.StatusNotFound,
			fmt.Sprintf("blob %q not found in repository", digest))
		return
	}

	size, err := h.blobs.Stat(digest)
	if err != nil {
		h.log.Error("blob head: stat blob in storage", "error", err, "repo", repo, "digest", digest)
		writeOCIError(w, "BLOB_UNKNOWN", http.StatusNotFound, "blob not found in storage")
		return
	}

	w.Header().Set("Content-Type", "application/octet-stream")
	w.Header().Set("Docker-Content-Digest", digest)
	w.Header().Set("Content-Length", strconv.FormatInt(size, 10))
	w.WriteHeader(http.StatusOK)
}