package xrpc

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"slices"

	"github.com/bluesky-social/indigo/atproto/atclient"
	"github.com/bluesky-social/indigo/atproto/syntax"
	"github.com/go-git/go-git/v5/plumbing/object"
	"tangled.org/core/knotserver/git"
)

func (x *Xrpc) GetBlob(w http.ResponseWriter, r *http.Request) {
	var (
		repoQuery = r.URL.Query().Get("repo")
		ref       = r.URL.Query().Get("ref") // ref can be empty (git.Open handles this)
		path      = r.URL.Query().Get("path")
	)

	repo, err := syntax.ParseATURI(repoQuery)
	if err != nil || repo.RecordKey() == "" {
		writeJson(w, http.StatusBadRequest, atclient.ErrorBody{Name: "BadRequest", Message: fmt.Sprintf("repo parameter invalid: %s", repoQuery)})
		return
	}

	l := x.logger.With("repo", repo, "ref", ref, "path", path)

	if path == "" {
		writeJson(w, http.StatusBadRequest, atclient.ErrorBody{Name: "BadRequest", Message: "missing path parameter"})
		return
	}

	file, err := x.getFile(r.Context(), repo, ref, path)
	if err != nil {
		// TODO: better error return
		l.Error("failed to get blob", "err", err)
		writeJson(w, http.StatusInternalServerError, atclient.ErrorBody{Name: "InternalServerError", Message: "failed to get blob"})
		return
	}

	reader, err := file.Reader()
	if err != nil {
		l.Error("failed to read blob", "err", err)
		writeJson(w, http.StatusInternalServerError, atclient.ErrorBody{Name: "InternalServerError", Message: "failed to read the blob"})
		return
	}
	defer reader.Close()

	w.Header().Set("Content-Type", "application/octet-stream")
	if _, err := io.Copy(w, reader); err != nil {
		l.Error("failed to serve the blob", "err", err)
	}
}

func (x *Xrpc) getFile(ctx context.Context, repo syntax.ATURI, ref, path string) (*object.File, error) {
	repoPath, err := x.makeRepoPath(ctx, repo)
	if err != nil {
		return nil, fmt.Errorf("resolving repo at-uri: %w", err)
	}

	gr, err := git.Open(repoPath, ref)
	if err != nil {
		return nil, fmt.Errorf("opening git repo: %w", err)
	}

	return gr.File(path)
}

var textualMimeTypes = []string{
	"application/json",
	"application/xml",
	"application/yaml",
	"application/x-yaml",
	"application/toml",
	"application/javascript",
	"application/ecmascript",
}

// isTextualMimeType returns true if the MIME type represents textual content
// that should be served as text/plain for security reasons
func isTextualMimeType(mimeType string) bool {
	return slices.Contains(textualMimeTypes, mimeType)
}