package gitea

import (
	"code.gitea.io/sdk/gitea"
	"code.mrmelon54.com/melon/tools/utils"
	"context"
	_ "embed"
	"encoding/gob"
	"fmt"
	"github.com/google/uuid"
	"github.com/gorilla/mux"
	"golang.org/x/oauth2"
	"html/template"
	"net/http"
	"os"
	"strings"
)

//go:embed pages/index.go.html
var indexTemplate string

type Module struct {
	sessionWrapper func(cb func(http.ResponseWriter, *http.Request, *utils.State)) func(rw http.ResponseWriter, req *http.Request)
	oauthClient    *oauth2.Config
}

type giteaKeyType int

const (
	KeyOauthClient = giteaKeyType(iota)
	KeyUser
	KeyState
	KeyAccessToken
	KeyRefreshToken
)

func New() *Module {
	gob.Register(new(giteaKeyType))
	return &Module{}
}

func (m *Module) GetName() string     { return "Gitea" }
func (m *Module) GetEndpoint() string { return "/gitea" }

func (m *Module) SetupModule(router *mux.Router, f func(cb func(http.ResponseWriter, *http.Request, *utils.State)) func(rw http.ResponseWriter, req *http.Request)) {
	m.sessionWrapper = f
	m.oauthClient = &oauth2.Config{
		ClientID:     os.Getenv("GITEA_CLIENT_ID"),
		ClientSecret: os.Getenv("GITEA_CLIENT_SECRET"),
		Scopes:       []string{"openid"},
		Endpoint: oauth2.Endpoint{
			AuthURL:  os.Getenv("GITEA_AUTHORIZE_URL"),
			TokenURL: os.Getenv("GITEA_TOKEN_URL"),
		},
		RedirectURL: os.Getenv("GITEA_REDIRECT_URL"),
	}
	router.HandleFunc("/", m.getClient(m.homepage))
	router.HandleFunc("/login", m.sessionWrapper(m.loginPage))
}

func (m *Module) getClient(cb func(http.ResponseWriter, *http.Request, *utils.State, *gitea.Client)) func(rw http.ResponseWriter, req *http.Request) {
	return m.sessionWrapper(func(rw http.ResponseWriter, req *http.Request, state *utils.State) {
		if v, ok := utils.GetStateValue[*gitea.Client](state, KeyOauthClient); ok {
			cb(rw, req, state, v)
			return
		}
		http.Redirect(rw, req, "/gitea/login", http.StatusTemporaryRedirect)
	})
}

func (m *Module) homepage(rw http.ResponseWriter, req *http.Request, state *utils.State, giteaClient *gitea.Client) {
	myUser, _, err := giteaClient.GetMyUserInfo()
	if err != nil {
		state.Del(KeyOauthClient)
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}
	orgs, _, err := giteaClient.ListMyOrgs(gitea.ListOrgsOptions{})
	if err != nil {
		http.Error(rw, err.Error(), http.StatusInternalServerError)
		return
	}
	orgSimple := make([]struct{ Name string }, len(orgs))
	for i, j := range orgs {
		orgSimple[i] = struct{ Name string }{j.UserName}
	}
	selOrg := ""
	myOrg := ""
	repoSimple := make([]struct{ Name string }, 0)
	selRepo := ""
	selModule := ""
	selCommitTime := ""
	selCommitHash := ""

	q := req.URL.Query()
	if q.Has("org") {
		selOrg = q.Get("org")
		var repos []*gitea.Repository
		if selOrg == "$me" {
			myOrg = myUser.UserName
			repos, _, err = giteaClient.ListMyRepos(gitea.ListReposOptions{ListOptions: gitea.ListOptions{Page: 0, PageSize: 100}})
		} else {
			myOrg = selOrg
			repos, _, err = giteaClient.ListOrgRepos(myOrg, gitea.ListOrgReposOptions{ListOptions: gitea.ListOptions{Page: 0, PageSize: 100}})
		}
		if err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}
		repoSimple = make([]struct{ Name string }, len(repos))
		for i, j := range repos {
			repoSimple[i] = struct{ Name string }{Name: j.Name}
		}

		if q.Has("repo") {
			selRepo = q.Get("repo")
			repo, _, err := giteaClient.GetRepo(myOrg, selRepo)
			if err != nil {
				http.Error(rw, "GetRepo: "+err.Error(), http.StatusInternalServerError)
				return
			}
			refs, _, err := giteaClient.GetRepoRefs(myOrg, selRepo, "heads/"+repo.DefaultBranch)
			if err != nil {
				http.Error(rw, "GetRepoRefs: "+err.Error(), http.StatusInternalServerError)
				return
			}
			if len(refs) == 1 {
				ref := refs[0]
				commit, _, err := giteaClient.GetSingleCommit(myOrg, selRepo, ref.Object.SHA)
				if err != nil {
					http.Error(rw, "GetSingleCommit: "+err.Error(), http.StatusInternalServerError)
					return
				}
				selCommitTime = commit.CommitMeta.Created.UTC().Format("20060102150405")
				selCommitHash = commit.CommitMeta.SHA[:12]
				goMod, _, err := giteaClient.GetFile(myOrg, selRepo, ref.Object.SHA, "go.mod")
				if err != nil {
					http.Error(rw, "go.mod: "+err.Error(), http.StatusInternalServerError)
					return
				}
				goModStr := string(goMod)
				goModIdx := strings.Index(goModStr, "\n")
				goModLine := goModStr[:goModIdx]
				goModSpace := strings.Index(goModLine, " ")
				selModule = goModLine[goModSpace+1:]
			}
		}
	}

	tmp, err := template.New("homepage").Parse(indexTemplate)
	if err != nil {
		fmt.Println("Template parse error:", err)
		return
	}
	err = tmp.Execute(rw, struct {
		Username   string
		Orgs       []struct{ Name string }
		Repos      []struct{ Name string }
		MyOrg      string
		SelOrg     string
		ShowOrg    bool
		SelModule  string
		ShowRepo   bool
		CommitTime string
		CommitHash string
	}{
		Username:   myUser.UserName,
		Orgs:       orgSimple,
		Repos:      repoSimple,
		MyOrg:      myOrg,
		SelOrg:     selOrg,
		SelModule:  selModule,
		ShowOrg:    myOrg != "",
		ShowRepo:   selModule != "",
		CommitTime: selCommitTime,
		CommitHash: selCommitHash,
	})
	if err != nil {
		fmt.Println("Template execute error:", err)
		return
	}
}

func (m *Module) loginPage(rw http.ResponseWriter, req *http.Request, state *utils.State) {
	if myUser, ok := utils.GetStateValue[*string](state, KeyUser); ok {
		if myUser != nil {
			http.Redirect(rw, req, "/gitea", http.StatusTemporaryRedirect)
			return
		}
	}

	if flowState, ok := utils.GetStateValue[uuid.UUID](state, KeyState); ok {
		q := req.URL.Query()
		if q.Has("code") && q.Has("state") {
			if q.Get("state") == flowState.String() {
				exchange, err := m.oauthClient.Exchange(context.Background(), q.Get("code"))
				if err != nil {
					fmt.Println("Exchange token error:", err)
					return
				}
				c, err := gitea.NewClient(os.Getenv("GITEA_SERVER"), gitea.SetToken(exchange.AccessToken))
				if err != nil {
					fmt.Println("Create client error:", err)
					return
				}
				state.Put(KeyOauthClient, c)
				state.Put(KeyAccessToken, exchange.AccessToken)
				state.Put(KeyRefreshToken, exchange.RefreshToken)
				http.Redirect(rw, req, "/gitea", http.StatusTemporaryRedirect)
				return
			}
			http.Error(rw, "OAuth flow state doesn't match\n", http.StatusBadRequest)
			return
		}
	}

	flowState := uuid.New()
	state.Put(KeyState, flowState)

	http.Redirect(rw, req, m.oauthClient.AuthCodeURL(flowState.String(), oauth2.AccessTypeOffline), http.StatusTemporaryRedirect)
}

func (m *Module) fetchRepos(giteaClient *gitea.Client) {
	repos, _, err := giteaClient.ListOrgRepos("snow", gitea.ListOrgReposOptions{ListOptions: gitea.ListOptions{Page: 0, PageSize: 100}})
	if err != nil {
		fmt.Println(err)
		return
	}
	for _, myRepo := range repos {
		refs, _, err := giteaClient.GetRepoRefs("snow", myRepo.Name, "heads")
		if err != nil {
			fmt.Println(err)
			return
		}
		fmt.Println(len(refs))
		for _, myRef := range refs {
			if myRef.Ref == "refs/heads/"+myRepo.DefaultBranch {
				fmt.Println(myRef.Ref)
				return
			}
		}
		fmt.Println("Can't find default branch")
	}
}