package xrpc

import (
	"context"
	"fmt"
	"math"
	"net/http"
	"time"

	"github.com/bluesky-social/indigo/atproto/atclient"
	"github.com/bluesky-social/indigo/atproto/syntax"
	"tangled.org/core/api/tangled"
	"tangled.org/core/knotserver/git"
)

func (x *Xrpc) ListLanguages(w http.ResponseWriter, r *http.Request) {
	var (
		repoQuery = r.URL.Query().Get("repo")
		ref       = r.URL.Query().Get("ref")
	)
	l := x.logger.With("repo", repoQuery, "ref", ref)

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

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

	writeJson(w, http.StatusOK, out)
}

func (x *Xrpc) listLanguages(ctx context.Context, repo syntax.ATURI, ref string) (*tangled.GitTempListLanguages_Output, 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)
	}

	ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
	defer cancel()

	sizes, err := gr.AnalyzeLanguages(ctx)
	if err != nil {
		return nil, fmt.Errorf("analyzing languages: %w", err)
	}

	return &tangled.GitTempListLanguages_Output{
		Ref:       ref,
		Languages: sizesToLanguages(sizes),
	}, nil
}

func sizesToLanguages(sizes git.LangBreakdown) []*tangled.GitTempListLanguages_Language {
	var apiLanguages []*tangled.GitTempListLanguages_Language
	var totalSize int64
	for _, size := range sizes {
		totalSize += size
	}

	for name, size := range sizes {
		percentagef64 := float64(size) / float64(totalSize) * 100
		percentage := math.Round(percentagef64)

		lang := &tangled.GitTempListLanguages_Language{
			Name:       name,
			Size:       size,
			Percentage: int64(percentage),
		}

		apiLanguages = append(apiLanguages, lang)
	}

	return apiLanguages
}