package xrpc

import (
	"encoding/json"
	"net/http"
	"net/url"
	"path/filepath"

	"tangled.sh/tangled.sh/core/api/tangled"
	"tangled.sh/tangled.sh/core/knotserver/git"
	xrpcerr "tangled.sh/tangled.sh/core/xrpc/errors"
)

func (x *Xrpc) RepoTree(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	repo := r.URL.Query().Get("repo")
	repoPath, err := x.parseRepoParam(repo)
	if err != nil {
		writeError(w, err.(xrpcerr.XrpcError), http.StatusBadRequest)
		return
	}

	refParam := r.URL.Query().Get("ref")
	if refParam == "" {
		writeError(w, xrpcerr.NewXrpcError(
			xrpcerr.WithTag("InvalidRequest"),
			xrpcerr.WithMessage("missing ref parameter"),
		), http.StatusBadRequest)
		return
	}

	path := r.URL.Query().Get("path")
	// path can be empty (defaults to root)

	ref, err := url.QueryUnescape(refParam)
	if err != nil {
		writeError(w, xrpcerr.NewXrpcError(
			xrpcerr.WithTag("InvalidRequest"),
			xrpcerr.WithMessage("invalid ref parameter"),
		), http.StatusBadRequest)
		return
	}

	gr, err := git.Open(repoPath, ref)
	if err != nil {
		x.Logger.Error("failed to open git repository", "error", err, "path", repoPath, "ref", ref)
		writeError(w, xrpcerr.NewXrpcError(
			xrpcerr.WithTag("RefNotFound"),
			xrpcerr.WithMessage("repository or ref not found"),
		), http.StatusNotFound)
		return
	}

	files, err := gr.FileTree(ctx, path)
	if err != nil {
		x.Logger.Error("failed to get file tree", "error", err, "path", path)
		writeError(w, xrpcerr.NewXrpcError(
			xrpcerr.WithTag("PathNotFound"),
			xrpcerr.WithMessage("failed to read repository tree"),
		), http.StatusNotFound)
		return
	}

	// convert NiceTree -> tangled.RepoTree_TreeEntry
	treeEntries := make([]*tangled.RepoTree_TreeEntry, len(files))
	for i, file := range files {
		entry := &tangled.RepoTree_TreeEntry{
			Name:       file.Name,
			Mode:       file.Mode,
			Size:       file.Size,
			Is_file:    file.IsFile,
			Is_subtree: file.IsSubtree,
		}

		if file.LastCommit != nil {
			entry.Last_commit = &tangled.RepoTree_LastCommit{
				Hash:    file.LastCommit.Hash.String(),
				Message: file.LastCommit.Message,
				When:    file.LastCommit.When.Format("2006-01-02T15:04:05.000Z"),
			}
		}

		treeEntries[i] = entry
	}

	var parentPtr *string
	if path != "" {
		parentPtr = &path
	}

	var dotdotPtr *string
	if path != "" {
		dotdot := filepath.Dir(path)
		if dotdot != "." {
			dotdotPtr = &dotdot
		}
	}

	response := tangled.RepoTree_Output{
		Ref:    ref,
		Parent: parentPtr,
		Dotdot: dotdotPtr,
		Files:  treeEntries,
	}

	w.Header().Set("Content-Type", "application/json")
	if err := json.NewEncoder(w).Encode(response); err != nil {
		x.Logger.Error("failed to encode response", "error", err)
		writeError(w, xrpcerr.NewXrpcError(
			xrpcerr.WithTag("InternalServerError"),
			xrpcerr.WithMessage("failed to encode response"),
		), http.StatusInternalServerError)
		return
	}
}