package gitea

import (
	"bytes"
	"code.gitea.io/sdk/gitea"
	"code.mrmelon54.com/melon/tools/module/gitea/assets"
	"code.mrmelon54.com/melon/tools/utils"
	"context"
	_ "embed"
	"encoding/gob"
	"fmt"
	"github.com/google/uuid"
	"github.com/gorilla/mux"
	"golang.org/x/oauth2"
	"gopkg.in/yaml.v3"
	"html/template"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

var (
	//go:embed pages/index.go.html
	indexTemplate string
	//go:embed pages/waffle.go.html
	waffleTemplate string
	returnCookie   = "melon-tools-return-gitea"
)

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))
	router.PathPrefix("/spec/{org}/{repo}/{sha}/{spec:.+}").HandlerFunc(m.getClient(m.specPage))
	router.PathPrefix("/spec-raw/{org}/{repo}/{sha}/{spec:.+}").HandlerFunc(m.getClient(m.specRawPage))
	router.PathPrefix("/waffle").HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		p := filepath.Join("waffle", "assets", filepath.Base(req.URL.Path))
		open, err := assets.WaffleAssets.Open(p)
		if err != nil {
			http.NotFound(rw, req)
			return
		}
		stat, err := open.Stat()
		if err != nil {
			http.NotFound(rw, req)
			return
		}
		seeker, ok := open.(io.ReadSeeker)
		if ok {
			http.ServeContent(rw, req, p, stat.ModTime(), seeker)
		} else {
			http.NotFound(rw, req)
		}
	})
}

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.SetCookie(rw, &http.Cookie{
			Name:    returnCookie,
			Value:   req.RequestURI,
			Path:    "/gitea",
			Expires: time.Now().Add(time.Hour * 1),
			MaxAge:  3600,
		})
		http.Redirect(rw, req, "/gitea/login", http.StatusTemporaryRedirect)
	})
}

func (m *Module) homepage(rw http.ResponseWriter, req *http.Request, state *utils.State, giteaClient *gitea.Client) {
	cookie, err := req.Cookie(returnCookie)
	if err == nil {
		if cookie.Valid() != nil {
			http.SetCookie(rw, &http.Cookie{Name: returnCookie, Value: "", Path: "/gitea", Expires: time.Now().Add(-time.Hour), MaxAge: 0})
			http.Redirect(rw, req, cookie.Value, http.StatusTemporaryRedirect)
			return
		}
	}

	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
		Private bool
	}, 0)
	selRepo := ""
	selModule := ""
	selCommitTime := ""
	selCommitHash := ""
	selCommitHashShort := ""
	mySpecs := make([]struct {
		Name string
		Code int
	}, 0)

	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: 50}})
		} else {
			myOrg = selOrg
			repos, _, err = giteaClient.ListOrgRepos(myOrg, gitea.ListOrgReposOptions{ListOptions: gitea.ListOptions{Page: 0, PageSize: 50}})
		}
		if err != nil {
			http.Error(rw, err.Error(), http.StatusInternalServerError)
			return
		}
		repoSimple = make([]struct {
			Name    string
			Private bool
		}, len(repos))
		for i, j := range repos {
			repoSimple[i] = struct {
				Name    string
				Private bool
			}{Name: j.Name, Private: j.Private}
		}

		if q.Has("repo") {
			selRepo = q.Get("repo")
			repo, resp, err := giteaClient.GetRepo(myOrg, selRepo)
			if err != nil {
				if resp.StatusCode != http.StatusNotFound {
					http.Error(rw, "GetRepo: "+err.Error(), http.StatusInternalServerError)
					return
				}
			}
			refs, resp, err := giteaClient.GetRepoRefs(myOrg, selRepo, "heads/"+repo.DefaultBranch)
			if err != nil {
				if resp.StatusCode != http.StatusNotFound {
					http.Error(rw, "GetRepoRefs: "+err.Error(), http.StatusInternalServerError)
					return
				}
				refs = make([]*gitea.Reference, 0)
			}
			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
				selCommitHashShort = commit.CommitMeta.SHA[:12]
				goMod, resp, err := giteaClient.GetFile(myOrg, selRepo, ref.Object.SHA, "go.mod")
				if err != nil {
					if resp.StatusCode != http.StatusNotFound {
						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:]
				if resp.StatusCode == http.StatusNotFound {
					selModule = ""
				}

				trees, resp, err := giteaClient.GetTrees(myOrg, selRepo, ref.Object.SHA, true)
				if err != nil {
					if resp.StatusCode != http.StatusNotFound {
						http.Error(rw, "%s: "+err.Error(), http.StatusInternalServerError)
						return
					}
				}
				for _, i := range trees.Entries {
					switch filepath.Ext(i.Path) {
					case ".yml", ".yaml":
						file, resp, err := giteaClient.GetFile(myOrg, selRepo, ref.Object.SHA, i.Path)
						if err != nil {
							switch resp.StatusCode {
							case http.StatusForbidden, http.StatusUnauthorized, http.StatusNotFound:
								mySpecs = append(mySpecs, struct {
									Name string
									Code int
								}{Name: i.Path, Code: resp.StatusCode})
							}
							continue
						}
						a := struct {
							OpenAPI string `yaml:"openapi"`
						}{}
						err = yaml.Unmarshal(file, &a)
						if err != nil || a.OpenAPI == "" {
							continue
						}
						mySpecs = append(mySpecs, struct {
							Name string
							Code int
						}{Name: i.Path, Code: http.StatusOK})
					}
				}
			}
		}
	}

	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
			Private bool
		}
		MyOrg           string
		SelOrg          string
		SelRepo         string
		ShowOrg         bool
		SelModule       string
		ShowGoMod       bool
		CommitTime      string
		CommitHash      string
		CommitHashShort string
		ShowSpec        bool
		Specs           []struct {
			Name string
			Code int
		}
	}{
		Username:        myUser.UserName,
		Orgs:            orgSimple,
		Repos:           repoSimple,
		MyOrg:           myOrg,
		SelOrg:          selOrg,
		SelRepo:         selRepo,
		SelModule:       selModule,
		ShowOrg:         myOrg != "",
		ShowGoMod:       selModule != "",
		CommitTime:      selCommitTime,
		CommitHash:      selCommitHash,
		CommitHashShort: selCommitHashShort,
		ShowSpec:        len(mySpecs) > 0,
		Specs:           mySpecs,
	})
	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) specPage(rw http.ResponseWriter, req *http.Request, state *utils.State, giteaClient *gitea.Client) {
	vars := mux.Vars(req)
	myOrg := vars["org"]
	myRepo := vars["repo"]
	mySha := vars["sha"]
	mySpec := vars["spec"]

	contents, _, err := giteaClient.GetContents(myOrg, myRepo, mySha, mySpec)
	if err != nil {
		http.Error(rw, "OpenAPI spec: "+err.Error(), http.StatusInternalServerError)
		return
	}

	tmp, err := template.New("waffle").Parse(waffleTemplate)
	if err != nil {
		fmt.Println("Template parse error:", err)
		return
	}
	err = tmp.Execute(rw, struct {
		LoadUrls []struct {
			Url  string `json:"url"`
			Name string `json:"name"`
		}
		LoadMain string
	}{
		LoadUrls: []struct {
			Url  string `json:"url"`
			Name string `json:"name"`
		}{
			{Url: fmt.Sprintf("/gitea/spec-raw/%s/%s/%s/%s", myOrg, myRepo, mySha, mySpec), Name: contents.Name},
		},
		LoadMain: contents.Name,
	})
	if err != nil {
		fmt.Println("Template execute error:", err)
		return
	}
}

func (m *Module) specRawPage(rw http.ResponseWriter, req *http.Request, state *utils.State, giteaClient *gitea.Client) {
	vars := mux.Vars(req)
	myOrg := vars["org"]
	myRepo := vars["repo"]
	mySha := vars["sha"]
	mySpec := vars["spec"]

	open, _, err := giteaClient.GetFile(myOrg, myRepo, mySha, mySpec)
	if err != nil {
		http.Error(rw, "OpenAPI spec raw: "+err.Error(), http.StatusInternalServerError)
		return
	}
	http.ServeContent(rw, req, mySpec, time.Now(), bytes.NewReader(open))
}