// Copyright 2024 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package repo

import (
	"fmt"
	"html/template"
	"net/http"
	"path"
	"strings"
	"time"

	"code.gitea.io/gitea/models/db"
	git_model "code.gitea.io/gitea/models/git"
	access_model "code.gitea.io/gitea/models/perm/access"
	repo_model "code.gitea.io/gitea/models/repo"
	unit_model "code.gitea.io/gitea/models/unit"
	"code.gitea.io/gitea/modules/git"
	"code.gitea.io/gitea/modules/log"
	repo_module "code.gitea.io/gitea/modules/repository"
	"code.gitea.io/gitea/modules/setting"
	"code.gitea.io/gitea/modules/svg"
	"code.gitea.io/gitea/modules/util"
	"code.gitea.io/gitea/routers/web/feed"
	"code.gitea.io/gitea/services/context"
	repo_service "code.gitea.io/gitea/services/repository"
)

func checkOutdatedBranch(ctx *context.Context) {
	if !(ctx.Repo.IsAdmin() || ctx.Repo.IsOwner()) {
		return
	}

	// get the head commit of the branch since ctx.Repo.CommitID is not always the head commit of `ctx.Repo.BranchName`
	commit, err := ctx.Repo.GitRepo.GetBranchCommit(ctx.Repo.BranchName)
	if err != nil {
		log.Error("GetBranchCommitID: %v", err)
		// Don't return an error page, as it can be rechecked the next time the user opens the page.
		return
	}

	dbBranch, err := git_model.GetBranch(ctx, ctx.Repo.Repository.ID, ctx.Repo.BranchName)
	if err != nil {
		log.Error("GetBranch: %v", err)
		// Don't return an error page, as it can be rechecked the next time the user opens the page.
		return
	}

	if dbBranch.CommitID != commit.ID.String() {
		ctx.Flash.Warning(ctx.Tr("repo.error.broken_git_hook", "https://docs.gitea.com/help/faq#push-hook--webhook--actions-arent-running"), true)
	}
}

func prepareHomeSidebarRepoTopics(ctx *context.Context) {
	topics, err := db.Find[repo_model.Topic](ctx, &repo_model.FindTopicOptions{
		RepoID: ctx.Repo.Repository.ID,
	})
	if err != nil {
		ctx.ServerError("models.FindTopics", err)
		return
	}
	ctx.Data["Topics"] = topics
}

func prepareOpenWithEditorApps(ctx *context.Context) {
	var tmplApps []map[string]any
	apps := setting.Config().Repository.OpenWithEditorApps.Value(ctx)
	if len(apps) == 0 {
		apps = setting.DefaultOpenWithEditorApps()
	}
	for _, app := range apps {
		schema, _, _ := strings.Cut(app.OpenURL, ":")
		var iconHTML template.HTML
		if schema == "vscode" || schema == "vscodium" || schema == "jetbrains" {
			iconHTML = svg.RenderHTML(fmt.Sprintf("gitea-%s", schema), 16, "tw-mr-2")
		} else {
			iconHTML = svg.RenderHTML("gitea-git", 16, "tw-mr-2") // TODO: it could support user's customized icon in the future
		}
		tmplApps = append(tmplApps, map[string]any{
			"DisplayName": app.DisplayName,
			"OpenURL":     app.OpenURL,
			"IconHTML":    iconHTML,
		})
	}
	ctx.Data["OpenWithEditorApps"] = tmplApps
}

func prepareHomeSidebarCitationFile(ctx *context.Context, entry *git.TreeEntry) {
	if entry.Name() != "" {
		return
	}
	tree, err := ctx.Repo.Commit.SubTree(ctx.Repo.TreePath)
	if err != nil {
		HandleGitError(ctx, "Repo.Commit.SubTree", err)
		return
	}
	allEntries, err := tree.ListEntries()
	if err != nil {
		ctx.ServerError("ListEntries", err)
		return
	}
	for _, entry := range allEntries {
		if entry.Name() == "CITATION.cff" || entry.Name() == "CITATION.bib" {
			// Read Citation file contents
			if content, err := entry.Blob().GetBlobContent(setting.UI.MaxDisplayFileSize); err != nil {
				log.Error("checkCitationFile: GetBlobContent: %v", err)
			} else {
				ctx.Data["CitiationExist"] = true
				ctx.PageData["citationFileContent"] = content
				break
			}
		}
	}
}

func prepareHomeSidebarLicenses(ctx *context.Context) {
	repoLicenses, err := repo_model.GetRepoLicenses(ctx, ctx.Repo.Repository)
	if err != nil {
		ctx.ServerError("GetRepoLicenses", err)
		return
	}
	ctx.Data["DetectedRepoLicenses"] = repoLicenses.StringList()
	ctx.Data["LicenseFileName"] = repo_service.LicenseFileName
}

func prepareToRenderDirectory(ctx *context.Context) {
	entries := renderDirectoryFiles(ctx, 1*time.Second)
	if ctx.Written() {
		return
	}

	if ctx.Repo.TreePath != "" {
		ctx.Data["HideRepoInfo"] = true
		ctx.Data["Title"] = ctx.Tr("repo.file.title", ctx.Repo.Repository.Name+"/"+path.Base(ctx.Repo.TreePath), ctx.Repo.RefName)
	}

	subfolder, readmeFile, err := findReadmeFileInEntries(ctx, entries, true)
	if err != nil {
		ctx.ServerError("findReadmeFileInEntries", err)
		return
	}

	prepareToRenderReadmeFile(ctx, subfolder, readmeFile)
}

func prepareHomeSidebarLanguageStats(ctx *context.Context) {
	langs, err := repo_model.GetTopLanguageStats(ctx, ctx.Repo.Repository, 5)
	if err != nil {
		ctx.ServerError("Repo.GetTopLanguageStats", err)
		return
	}

	ctx.Data["LanguageStats"] = langs
}

func prepareHomeSidebarLatestRelease(ctx *context.Context) {
	if !ctx.Repo.Repository.UnitEnabled(ctx, unit_model.TypeReleases) {
		return
	}

	release, err := repo_model.GetLatestReleaseByRepoID(ctx, ctx.Repo.Repository.ID)
	if err != nil && !repo_model.IsErrReleaseNotExist(err) {
		ctx.ServerError("GetLatestReleaseByRepoID", err)
		return
	}

	if release != nil {
		if err = release.LoadAttributes(ctx); err != nil {
			ctx.ServerError("release.LoadAttributes", err)
			return
		}
		ctx.Data["LatestRelease"] = release
	}
}

func renderHomeCode(ctx *context.Context) {
	ctx.Data["PageIsViewCode"] = true
	ctx.Data["RepositoryUploadEnabled"] = setting.Repository.Upload.Enabled
	prepareOpenWithEditorApps(ctx)

	if ctx.Repo.Commit == nil || ctx.Repo.Repository.IsEmpty || ctx.Repo.Repository.IsBroken() {
		showEmpty := true
		var err error
		if ctx.Repo.GitRepo != nil {
			showEmpty, err = ctx.Repo.GitRepo.IsEmpty()
			if err != nil {
				log.Error("GitRepo.IsEmpty: %v", err)
				ctx.Repo.Repository.Status = repo_model.RepositoryBroken
				showEmpty = true
				ctx.Flash.Error(ctx.Tr("error.occurred"), true)
			}
		}
		if showEmpty {
			ctx.HTML(http.StatusOK, tplRepoEMPTY)
			return
		}

		// the repo is not really empty, so we should update the modal in database
		// such problem may be caused by:
		// 1) an error occurs during pushing/receiving.  2) the user replaces an empty git repo manually
		// and even more: the IsEmpty flag is deeply broken and should be removed with the UI changed to manage to cope with empty repos.
		// it's possible for a repository to be non-empty by that flag but still 500
		// because there are no branches - only tags -or the default branch is non-extant as it has been 0-pushed.
		ctx.Repo.Repository.IsEmpty = false
		if err = repo_model.UpdateRepositoryCols(ctx, ctx.Repo.Repository, "is_empty"); err != nil {
			ctx.ServerError("UpdateRepositoryCols", err)
			return
		}
		if err = repo_module.UpdateRepoSize(ctx, ctx.Repo.Repository); err != nil {
			ctx.ServerError("UpdateRepoSize", err)
			return
		}

		// the repo's IsEmpty has been updated, redirect to this page to make sure middlewares can get the correct values
		link := ctx.Link
		if ctx.Req.URL.RawQuery != "" {
			link += "?" + ctx.Req.URL.RawQuery
		}
		ctx.Redirect(link)
		return
	}

	title := ctx.Repo.Repository.Owner.Name + "/" + ctx.Repo.Repository.Name
	if len(ctx.Repo.Repository.Description) > 0 {
		title += ": " + ctx.Repo.Repository.Description
	}
	ctx.Data["Title"] = title

	// Get Topics of this repo
	prepareHomeSidebarRepoTopics(ctx)
	if ctx.Written() {
		return
	}

	// Get current entry user currently looking at.
	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
	if err != nil {
		HandleGitError(ctx, "Repo.Commit.GetTreeEntryByPath", err)
		return
	}

	checkOutdatedBranch(ctx)

	if entry.IsDir() {
		prepareToRenderDirectory(ctx)
	} else {
		renderFile(ctx, entry)
	}
	if ctx.Written() {
		return
	}

	if ctx.Doer != nil {
		if err := ctx.Repo.Repository.GetBaseRepo(ctx); err != nil {
			ctx.ServerError("GetBaseRepo", err)
			return
		}

		opts := &git_model.FindRecentlyPushedNewBranchesOptions{
			Repo:     ctx.Repo.Repository,
			BaseRepo: ctx.Repo.Repository,
		}
		if ctx.Repo.Repository.IsFork {
			opts.BaseRepo = ctx.Repo.Repository.BaseRepo
		}

		baseRepoPerm, err := access_model.GetUserRepoPermission(ctx, opts.BaseRepo, ctx.Doer)
		if err != nil {
			ctx.ServerError("GetUserRepoPermission", err)
			return
		}

		if !opts.Repo.IsMirror && !opts.BaseRepo.IsMirror &&
			opts.BaseRepo.UnitEnabled(ctx, unit_model.TypePullRequests) &&
			baseRepoPerm.CanRead(unit_model.TypePullRequests) {
			ctx.Data["RecentlyPushedNewBranches"], err = git_model.FindRecentlyPushedNewBranches(ctx, ctx.Doer, opts)
			if err != nil {
				log.Error("FindRecentlyPushedNewBranches failed: %v", err)
			}
		}
	}

	var treeNames, paths []string
	branchLink := ctx.Repo.RepoLink + "/src/" + ctx.Repo.BranchNameSubURL()
	treeLink := branchLink
	if ctx.Repo.TreePath != "" {
		treeLink += "/" + util.PathEscapeSegments(ctx.Repo.TreePath)
		treeNames = strings.Split(ctx.Repo.TreePath, "/")
		for i := range treeNames {
			paths = append(paths, strings.Join(treeNames[:i+1], "/"))
		}
		ctx.Data["HasParentPath"] = true
		if len(paths)-2 >= 0 {
			ctx.Data["ParentPath"] = "/" + paths[len(paths)-2]
		}
	}

	isTreePathRoot := ctx.Repo.TreePath == ""
	if isTreePathRoot {
		prepareHomeSidebarLicenses(ctx)
		if ctx.Written() {
			return
		}
		prepareHomeSidebarCitationFile(ctx, entry)
		if ctx.Written() {
			return
		}

		prepareHomeSidebarLanguageStats(ctx)
		if ctx.Written() {
			return
		}

		prepareHomeSidebarLatestRelease(ctx)
		if ctx.Written() {
			return
		}
	}

	ctx.Data["Paths"] = paths
	ctx.Data["TreeLink"] = treeLink
	ctx.Data["TreeNames"] = treeNames
	ctx.Data["BranchLink"] = branchLink
	ctx.HTML(http.StatusOK, tplRepoHome)
}

// Home render repository home page
func Home(ctx *context.Context) {
	if setting.Other.EnableFeed {
		isFeed, _, showFeedType := feed.GetFeedType(ctx.PathParam(":reponame"), ctx.Req)
		if isFeed {
			switch {
			case ctx.Link == fmt.Sprintf("%s.%s", ctx.Repo.RepoLink, showFeedType):
				feed.ShowRepoFeed(ctx, ctx.Repo.Repository, showFeedType)
			case ctx.Repo.TreePath == "":
				feed.ShowBranchFeed(ctx, ctx.Repo.Repository, showFeedType)
			case ctx.Repo.TreePath != "":
				feed.ShowFileFeed(ctx, ctx.Repo.Repository, showFeedType)
			}
			return
		}
	}

	checkHomeCodeViewable(ctx)
	if ctx.Written() {
		return
	}

	renderHomeCode(ctx)
}