package api

import (
	gitea "code.gitea.io/sdk/gitea"
	"encoding/json"
	"fmt"
	"git.lumeweb.com/LumeWeb/gitea-github-proxy/config"
	"github.com/google/go-github/v59/github"
	"github.com/gorilla/mux"
	"go.uber.org/zap"
	"net/http"
	"strconv"
)

type restApi struct {
	config *config.Config
	logger *zap.Logger
}

func newRestApi(cfg *config.Config, logger *zap.Logger) *restApi {
	return &restApi{config: cfg, logger: logger}
}

func (r restApi) handlerGetPullRequestFiles(w http.ResponseWriter, request *http.Request) {
	vars := mux.Vars(request)

	owner := vars["owner"]
	repo := vars["repo"]
	pullNumber := vars["pull_number"]

	client := r.getClientOrError(w)

	if client == nil {
		return
	}
	parsedPullNumber, err := strconv.ParseInt(pullNumber, 10, 64)
	if err != nil {
		http.Error(w, "Failed to parse pull number", http.StatusBadRequest)
		r.logger.Error("Failed to parse pull number", zap.Error(err))
		return
	}

	files, r2, err := client.ListPullRequestFiles(owner, repo, parsedPullNumber, gitea.ListPullRequestFilesOptions{
		ListOptions: r.getPagingOptions(request),
	})
	if err != nil {
		http.Error(w, "Failed to get pull request files", http.StatusInternalServerError)
		r.logger.Error("Failed to get pull request files", zap.Error(err))
		return
	}

	githubFiles := make([]*github.CommitFile, len(files))

	for i, file := range files {
		githubFiles[i] = convertCommitFile(file)
	}

	r.sendPagingHeaders(w, r2)
	r.respond(w, http.StatusOK, githubFiles)
}

func (r restApi) getPagingOptions(request *http.Request) gitea.ListOptions {
	page, _ := strconv.Atoi(request.URL.Query().Get("page"))
	perPage, _ := strconv.Atoi(request.URL.Query().Get("per_page"))

	return gitea.ListOptions{
		Page:     page,
		PageSize: perPage,
	}
}

func (r restApi) sendPagingHeaders(w http.ResponseWriter, apiResponse *gitea.Response) {
	links := []string{}

	baseURL := fmt.Sprintf("https://%s", r.config.Domain)

	joinStrings := func(elements []string, separator string) string {
		if len(elements) == 0 {
			return ""
		}
		result := elements[0]
		for i := 1; i < len(elements); i++ {
			result += separator + elements[i]
		}
		return result
	}
	joinLinks := func(links []string) string {
		return fmt.Sprintf("%s", joinStrings(links, ", "))
	}

	if apiResponse.FirstPage > 0 {
		links = append(links, fmt.Sprintf(`<%s?page=%d>; rel="first"`, baseURL, apiResponse.FirstPage))
	}
	if apiResponse.PrevPage > 0 {
		links = append(links, fmt.Sprintf(`<%s?page=%d>; rel="prev"`, baseURL, apiResponse.PrevPage))
	}
	if apiResponse.NextPage > 0 {
		links = append(links, fmt.Sprintf(`<%s?page=%d>; rel="next"`, baseURL, apiResponse.NextPage))
	}
	if apiResponse.LastPage > 0 {
		links = append(links, fmt.Sprintf(`<%s?page=%d>; rel="last"`, baseURL, apiResponse.LastPage))
	}

	if len(links) > 0 {
		w.Header().Add("Link", fmt.Sprintf("%s", joinLinks(links)))
	}
}

func (r restApi) respond(w http.ResponseWriter, status int, data interface{}) {
	jsonData, err := json.Marshal(data)
	if err != nil {
		http.Error(w, "Failed to marshal response", http.StatusInternalServerError)
		r.logger.Error("Failed to marshal response", zap.Error(err))
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	if data != nil {
		_, _ = w.Write(jsonData)
	}
}

func (r restApi) getClientOrError(w http.ResponseWriter) *gitea.Client {
	client, err := getClient(ClientParams{
		Config: r.config,
	})
	if err != nil {
		http.Error(w, "Failed to get Gitea client", http.StatusInternalServerError)
		r.logger.Error("Failed to get Gitea client", zap.Error(err))
		return nil
	}

	return client
}

func (r restApi) handlerGetTree(w http.ResponseWriter, request *http.Request) {
	vars := mux.Vars(request)
	owner := vars["owner"]
	repo := vars["repo"]
	treeSha := vars["tree_sha"]
	recursive := false

	if request.URL.Query().Has("recursive") {
		recursive = true
	}

	client := r.getClientOrError(w)

	if client == nil {
		return
	}

	tree, r2, err := client.GetTrees(owner, repo, treeSha, recursive)
	if err != nil {
		http.Error(w, "Failed to get tree", http.StatusInternalServerError)
		r.logger.Error("Failed to get tree", zap.Error(err))
		return
	}

	treeResponse := convertGitTree(tree)

	r.sendPagingHeaders(w, r2)
	r.respond(w, http.StatusOK, treeResponse)
}

func (r restApi) handleGetIssueComments(w http.ResponseWriter, request *http.Request) {
	vars := mux.Vars(request)
	owner := vars["owner"]
	repo := vars["repo"]
	issueNumber := vars["issue_number"]

	client := r.getClientOrError(w)

	if client == nil {
		return
	}

	issueNumberInt, err := strconv.Atoi(issueNumber)
	if err != nil {
		http.Error(w, "Failed to parse issue number", http.StatusBadRequest)
		r.logger.Error("Failed to parse issue number", zap.Error(err))
		return
	}

	comments, r2, err := client.ListIssueComments(owner, repo, int64(issueNumberInt), gitea.ListIssueCommentOptions{ListOptions: r.getPagingOptions(request)})
	if err != nil {
		http.Error(w, "Failed to get issue comments", http.StatusInternalServerError)
		r.logger.Error("Failed to get issue comments", zap.Error(err))
		return
	}

	ghComments := make([]*github.IssueComment, len(comments))

	for i, comment := range comments {
		reactions, _, _ := client.GetIssueCommentReactions(owner, repo, comment.ID)
		ghComments[i] = convertIssueComment(comment, reactions)
	}

	r.sendPagingHeaders(w, r2)
	r.respond(w, http.StatusOK, ghComments)

}

func (r restApi) handlerCreateIssueComment(w http.ResponseWriter, request *http.Request) {
	vars := mux.Vars(request)
	owner := vars["owner"]
	repo := vars["repo"]
	issueNumber := vars["issue_number"]

	client := r.getClientOrError(w)

	if client == nil {
		return
	}

	ghComment := github.IssueComment{}

	if err := r.parseJsonBody(request, &ghComment); err != nil {
		http.Error(w, "Failed to parse request body", http.StatusBadRequest)
		r.logger.Error("Failed to parse request body", zap.Error(err))
	}

	issueNumberInt, err := strconv.Atoi(issueNumber)
	if err != nil {
		http.Error(w, "Failed to parse issue number", http.StatusBadRequest)
		r.logger.Error("Failed to parse issue number", zap.Error(err))
		return
	}
	comment := gitea.CreateIssueCommentOption{
		Body: ghComment.GetBody(),
	}

	commentResponse, _, err := client.CreateIssueComment(owner, repo, int64(issueNumberInt), comment)
	if err != nil {
		http.Error(w, "Failed to create comment", http.StatusInternalServerError)
		r.logger.Error("Failed to create comment", zap.Error(err))
		return
	}

	r.respond(w, http.StatusCreated, commentResponse)
}

func (r restApi) handlerUpdateIssueComment(w http.ResponseWriter, request *http.Request) {
	vars := mux.Vars(request)
	owner := vars["owner"]
	repo := vars["repo"]
	commentID := vars["comment_id"]

	client := r.getClientOrError(w)

	if client == nil {
		return
	}

	ghComment := github.IssueComment{}

	if err := r.parseJsonBody(request, &ghComment); err != nil {
		http.Error(w, "Failed to parse request body", http.StatusBadRequest)
		r.logger.Error("Failed to parse request body", zap.Error(err))
	}

	commentIDInt, err := strconv.Atoi(commentID)
	if err != nil {
		http.Error(w, "Failed to parse comment ID", http.StatusBadRequest)
		r.logger.Error("Failed to parse comment ID", zap.Error(err))
		return
	}

	comment := gitea.EditIssueCommentOption{
		Body: request.FormValue("body"),
	}

	commentResponse, _, err := client.EditIssueComment(owner, repo, int64(commentIDInt), comment)
	if err != nil {
		http.Error(w, "Failed to update comment", http.StatusInternalServerError)
		r.logger.Error("Failed to update comment", zap.Error(err))
		return
	}

	r.respond(w, http.StatusOK, commentResponse)
}

func (r restApi) parseJsonBody(request *http.Request, obj interface{}) error {
	if obj == nil {
		obj = make(map[string]interface{})
	}

	decoder := json.NewDecoder(request.Body)
	return decoder.Decode(obj)
}

func setupRestRoutes(params RouteParams) {
	logger := params.Logger
	cfg := params.Config
	r := params.R

	restApi := newRestApi(cfg, logger)

	setupRoutes := func(r *mux.Router) {
		r.HandleFunc("/repos/{owner}/{repo}/pulls/{pull_number}/files", restApi.handlerGetPullRequestFiles).Methods("GET")
		r.HandleFunc("/repos/{owner}/{repo}/git/trees/{tree_sha}", restApi.handlerGetTree).Methods("GET")

		// Comment routes
		r.HandleFunc("/repos/{owner}/{repo}/issues/{issue_number}/comments", restApi.handleGetIssueComments).Methods("GET")
		r.HandleFunc("/repos/{owner}/{repo}/issues/{issue_number}/comments", restApi.handlerCreateIssueComment).Methods("POST")
		r.HandleFunc("/repos/{owner}/{repo}/issues/comments/{comment_id}", restApi.handlerUpdateIssueComment).Methods("PATCH")
	}

	restRouter := r.PathPrefix("/api").Subrouter()
	restRouter.Use(githubRestVerifyMiddleware(params.Db))
	restRouter.Use(githubRestRequireAuthMiddleware(params.Config))

	setupRoutes(restRouter)
	setupRoutes(restRouter.PathPrefix("/v3").Subrouter())
}