package main

import (
	"crypto/rand"
	"encoding/base64"
	"errors"
	"fmt"
	"net/http"
	"time"

	"github.com/alexedwards/argon2id"
	"github.com/jackc/pgx/v5"
)

func handle_login(w http.ResponseWriter, r *http.Request, params map[string]any) {
	if r.Method != "POST" {
		err := templates.ExecuteTemplate(w, "login", params)
		if err != nil {

			http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

			http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

		}
		return
	}

	var user_id int
	username := r.PostFormValue("username")
	password := r.PostFormValue("password")

	var password_hash string
	err := database.QueryRow(r.Context(), "SELECT id, password FROM users WHERE username = $1", username).Scan(&user_id, &password_hash)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			params["login_error"] = "Unknown username"
			err := templates.ExecuteTemplate(w, "login", params)
			if err != nil {

				http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

			}
			return
		}

		http.Error(w, "Error querying user information:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error querying user information: "+err.Error(), http.StatusInternalServerError)

		return
	}

	match, err := argon2id.ComparePasswordAndHash(password, password_hash)
	if err != nil {

		http.Error(w, "Error comparing password and hash:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error comparing password and hash: "+err.Error(), http.StatusInternalServerError)

		return
	}

	if !match {
		params["login_error"] = "Invalid password"
		err := templates.ExecuteTemplate(w, "login", params)
		if err != nil {

			http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

			http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

			return
		}
		return
	}

	cookie_value, err := random_urlsafe_string(16)
	now := time.Now()
	expiry := now.Add(time.Duration(config.HTTP.CookieExpiry) * time.Second)

	cookie := http.Cookie{
		Name:     "session",
		Value:    cookie_value,
		SameSite: http.SameSiteLaxMode,
		HttpOnly: true,
		Secure:   false, // TODO
		Expires:  expiry,
		Path:     "/",
		// TODO: Expire
	}

	http.SetCookie(w, &cookie)

	_, err = database.Exec(r.Context(), "INSERT INTO sessions (user_id, session_id) VALUES ($1, $2)", user_id, cookie_value)
	if err != nil {

		http.Error(w, "Error inserting session:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error inserting session: "+err.Error(), http.StatusInternalServerError)

		return
	}

	http.Redirect(w, r, "/", http.StatusSeeOther)
}

func random_urlsafe_string(sz int) (string, error) {
	r := make([]byte, 3*sz)
	_, err := rand.Read(r)
	if err != nil {
		return "", fmt.Errorf("error generating random string: %w", err)
	}
	return base64.RawURLEncoding.EncodeToString(r), nil
}

package main

import (
	"fmt"
	"net/http"
	"strings"

	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/filemode"
	"github.com/go-git/go-git/v5/plumbing/format/diff"
	"go.lindenii.runxiyu.org/lindenii-common/misc"
)

type usable_file_patch struct {
	From   diff.File
	To     diff.File
	Chunks []diff.Chunk
}

func handle_repo_commit(w http.ResponseWriter, r *http.Request, params map[string]any) {
	group_name, repo_name, commit_id_specified_string := params["group_name"].(string), params["repo_name"].(string), params["commit_id"].(string)
	repo, description, err := open_git_repo(r.Context(), group_name, repo_name)
	if err != nil {

		http.Error(w, "Error opening repo:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error opening repo: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["repo_description"] = description
	commit_id_specified_string_without_suffix := strings.TrimSuffix(commit_id_specified_string, ".patch")
	commit_id := plumbing.NewHash(commit_id_specified_string_without_suffix)
	commit_object, err := repo.CommitObject(commit_id)
	if err != nil {

		http.Error(w, "Error getting commit object:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting commit object: "+err.Error(), http.StatusInternalServerError)

		return
	}
	if commit_id_specified_string_without_suffix != commit_id_specified_string {
		patch, err := format_patch_from_commit(commit_object)
		if err != nil {

			http.Error(w, "Error formatting patch:: "+err.Error(), http.StatusInternalServerError)

			http.Error(w, "Error formatting patch: "+err.Error(), http.StatusInternalServerError)

			return
		}
		fmt.Fprintln(w, patch)
		return
	}
	commit_id_string := commit_object.Hash.String()

	if commit_id_string != commit_id_specified_string {
		http.Redirect(w, r, commit_id_string, http.StatusSeeOther)
		return
	}

	params["commit_object"] = commit_object
	params["commit_id"] = commit_id_string

	parent_commit_hash, patch, err := get_patch_from_commit(commit_object)
	if err != nil {

		http.Error(w, "Error getting patch from commit:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting patch from commit: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["parent_commit_hash"] = parent_commit_hash.String()
	params["patch"] = patch

	// TODO: Remove unnecessary context
	// TODO: Prepend "+"/"-"/" " instead of solely distinguishing based on color
	usable_file_patches := make([]usable_file_patch, 0)
	for _, file_patch := range patch.FilePatches() {
		from, to := file_patch.Files()
		if from == nil {
			from = fake_diff_file_null
		}
		if to == nil {
			to = fake_diff_file_null
		}
		usable_file_patch := usable_file_patch{
			Chunks: file_patch.Chunks(),
			From:   from,
			To:     to,
		}
		usable_file_patches = append(usable_file_patches, usable_file_patch)
	}
	params["file_patches"] = usable_file_patches

	err = templates.ExecuteTemplate(w, "repo_commit", params)
	if err != nil {

		http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

		return
	}
}

type fake_diff_file struct {
	hash plumbing.Hash
	mode filemode.FileMode
	path string
}

func (f fake_diff_file) Hash() plumbing.Hash {
	return f.hash
}

func (f fake_diff_file) Mode() filemode.FileMode {
	return f.mode
}

func (f fake_diff_file) Path() string {
	return f.path
}

var fake_diff_file_null = fake_diff_file{
	hash: plumbing.NewHash("0000000000000000000000000000000000000000"),
	mode: misc.First_or_panic(filemode.New("100644")),
	path: "",
}

package main

import (
	"net/http"
)

func handle_repo_index(w http.ResponseWriter, r *http.Request, params map[string]any) {
	group_name, repo_name := params["group_name"].(string), params["repo_name"].(string)
	repo, description, err := open_git_repo(r.Context(), group_name, repo_name)
	if err != nil {

		http.Error(w, "Error opening repo:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error opening repo: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["repo_description"] = description
	head, err := repo.Head()
	if err != nil {

		http.Error(w, "Error getting repo HEAD:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting repo HEAD: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["ref"] = head.Name().Short()
	head_hash := head.Hash()
	recent_commits, err := get_recent_commits(repo, head_hash, 3)
	if err != nil {

		http.Error(w, "Error getting recent commits:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting recent commits: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["commits"] = recent_commits
	commit_object, err := repo.CommitObject(head_hash)
	if err != nil {

		http.Error(w, "Error getting commit object:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting commit object: "+err.Error(), http.StatusInternalServerError)

		return
	}
	tree, err := commit_object.Tree()
	if err != nil {

		http.Error(w, "Error getting file tree:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting file tree: "+err.Error(), http.StatusInternalServerError)

		return
	}

	params["readme_filename"], params["readme"] = render_readme_at_tree(tree)
	params["files"] = build_display_git_tree(tree)

	params["clone_url"] = generate_ssh_remote_url(group_name, repo_name)

	err = templates.ExecuteTemplate(w, "repo_index", params)
	if err != nil {

		http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

		return
	}
}

package main

import (
	"net/http"

	"github.com/go-git/go-git/v5/plumbing"
)

// TODO: I probably shouldn't include *all* commits here...
func handle_repo_log(w http.ResponseWriter, r *http.Request, params map[string]any) {
	group_name, repo_name, ref_name := params["group_name"].(string), params["repo_name"].(string), params["ref"].(string)
	repo, description, err := open_git_repo(r.Context(), group_name, repo_name)
	if err != nil {

		http.Error(w, "Error opening repo:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error opening repo: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["repo_description"] = description
	ref, err := repo.Reference(plumbing.NewBranchReferenceName(ref_name), true)
	if err != nil {

		http.Error(w, "Error getting repo reference:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting repo reference: "+err.Error(), http.StatusInternalServerError)

		return
	}
	ref_hash := ref.Hash()
	commits, err := get_recent_commits(repo, ref_hash, -1)
	if err != nil {

		http.Error(w, "Error getting recent commits:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting recent commits: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["commits"] = commits

	err = templates.ExecuteTemplate(w, "repo_log", params)
	if err != nil {

		http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

		return
	}
}

package main

import (
	"errors"
	"fmt"
	"net/http"
	"path"
	"strings"

	"github.com/go-git/go-git/v5/plumbing/object"
)

func handle_repo_raw(w http.ResponseWriter, r *http.Request, params map[string]any) {
	raw_path_spec := params["rest"].(string)
	group_name, repo_name, path_spec := params["group_name"].(string), params["repo_name"].(string), strings.TrimSuffix(raw_path_spec, "/")

	ref_type, ref_name, err := get_param_ref_and_type(r)
	if err != nil {
		if errors.Is(err, err_no_ref_spec) {
			ref_type = "head"
		} else {

			http.Error(w, "Error querying ref type:: "+err.Error(), http.StatusInternalServerError)

			http.Error(w, "Error querying ref type: "+err.Error(), http.StatusInternalServerError)

			return
		}
	}

	params["ref_type"], params["ref"], params["path_spec"] = ref_type, ref_name, path_spec

	repo, description, err := open_git_repo(r.Context(), group_name, repo_name)
	if err != nil {

		http.Error(w, "Error opening repo:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error opening repo: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["repo_description"] = description

	ref_hash, err := get_ref_hash_from_type_and_name(repo, ref_type, ref_name)
	if err != nil {

		http.Error(w, "Error getting ref hash:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting ref hash: "+err.Error(), http.StatusInternalServerError)

		return
	}

	commit_object, err := repo.CommitObject(ref_hash)
	if err != nil {

		http.Error(w, "Error getting commit object:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting commit object: "+err.Error(), http.StatusInternalServerError)

		return
	}
	tree, err := commit_object.Tree()
	if err != nil {

		http.Error(w, "Error getting file tree:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting file tree: "+err.Error(), http.StatusInternalServerError)

		return
	}

	var target *object.Tree
	if path_spec == "" {
		target = tree
	} else {
		target, err = tree.Tree(path_spec)
		if err != nil {
			file, err := tree.File(path_spec)
			if err != nil {

				http.Error(w, "Error retrieving path:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error retrieving path: "+err.Error(), http.StatusInternalServerError)

				return
			}
			if len(raw_path_spec) != 0 && raw_path_spec[len(raw_path_spec)-1] == '/' {
				http.Redirect(w, r, "../"+path_spec, http.StatusSeeOther)
				return
			}
			file_contents, err := file.Contents()
			if err != nil {

				http.Error(w, "Error reading file:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error reading file: "+err.Error(), http.StatusInternalServerError)

				return
			}
			fmt.Fprintln(w, file_contents)
			return
		}
	}

	if len(raw_path_spec) != 0 && raw_path_spec[len(raw_path_spec)-1] != '/' {
		http.Redirect(w, r, path.Base(path_spec)+"/", http.StatusSeeOther)
		return
	}

	params["files"] = build_display_git_tree(target)

	err = templates.ExecuteTemplate(w, "repo_raw_dir", params)
	if err != nil {

		http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

		return
	}
}

package main

import (
	"bytes"
	"errors"
	"html/template"
	"net/http"
	"path"
	"strings"

	chroma_formatters_html "github.com/alecthomas/chroma/v2/formatters/html"
	chroma_lexers "github.com/alecthomas/chroma/v2/lexers"
	chroma_styles "github.com/alecthomas/chroma/v2/styles"
	"github.com/go-git/go-git/v5/plumbing/object"
)

func handle_repo_tree(w http.ResponseWriter, r *http.Request, params map[string]any) {
	raw_path_spec := params["rest"].(string)
	group_name, repo_name, path_spec := params["group_name"].(string), params["repo_name"].(string), strings.TrimSuffix(raw_path_spec, "/")
	ref_type, ref_name, err := get_param_ref_and_type(r)
	if err != nil {
		if errors.Is(err, err_no_ref_spec) {
			ref_type = "head"
		} else {

			http.Error(w, "Error querying ref type:: "+err.Error(), http.StatusInternalServerError)

			http.Error(w, "Error querying ref type: "+err.Error(), http.StatusInternalServerError)

			return
		}
	}
	params["ref_type"], params["ref"], params["path_spec"] = ref_type, ref_name, path_spec
	repo, description, err := open_git_repo(r.Context(), group_name, repo_name)
	if err != nil {

		http.Error(w, "Error opening repo:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error opening repo: "+err.Error(), http.StatusInternalServerError)

		return
	}
	params["repo_description"] = description

	ref_hash, err := get_ref_hash_from_type_and_name(repo, ref_type, ref_name)
	if err != nil {

		http.Error(w, "Error getting ref hash:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting ref hash: "+err.Error(), http.StatusInternalServerError)

		return
	}
	commit_object, err := repo.CommitObject(ref_hash)
	if err != nil {

		http.Error(w, "Error getting commit object:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting commit object: "+err.Error(), http.StatusInternalServerError)

		return
	}
	tree, err := commit_object.Tree()
	if err != nil {

		http.Error(w, "Error getting file tree:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error getting file tree: "+err.Error(), http.StatusInternalServerError)

		return
	}

	var target *object.Tree
	if path_spec == "" {
		target = tree
	} else {
		target, err = tree.Tree(path_spec)
		if err != nil {
			file, err := tree.File(path_spec)
			if err != nil {

				http.Error(w, "Error retrieving path:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error retrieving path: "+err.Error(), http.StatusInternalServerError)

				return
			}
			if len(raw_path_spec) != 0 && raw_path_spec[len(raw_path_spec)-1] == '/' {
				http.Redirect(w, r, "../"+path_spec, http.StatusSeeOther)
				return
			}
			file_contents, err := file.Contents()
			if err != nil {

				http.Error(w, "Error reading file:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error reading file: "+err.Error(), http.StatusInternalServerError)

				return
			}
			lexer := chroma_lexers.Match(path_spec)
			if lexer == nil {
				lexer = chroma_lexers.Fallback
			}
			iterator, err := lexer.Tokenise(nil, file_contents)
			if err != nil {

				http.Error(w, "Error tokenizing code:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error tokenizing code: "+err.Error(), http.StatusInternalServerError)

				return
			}
			var formatted_unencapsulated bytes.Buffer
			style := chroma_styles.Get("autumn")
			formatter := chroma_formatters_html.New(chroma_formatters_html.WithClasses(true), chroma_formatters_html.TabWidth(8))
			err = formatter.Format(&formatted_unencapsulated, style, iterator)
			if err != nil {

				http.Error(w, "Error formatting code:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error formatting code: "+err.Error(), http.StatusInternalServerError)

				return
			}
			formatted_encapsulated := template.HTML(formatted_unencapsulated.Bytes())
			params["file_contents"] = formatted_encapsulated

			err = templates.ExecuteTemplate(w, "repo_tree_file", params)
			if err != nil {

				http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

				http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

				return
			}
			return
		}
	}

	if len(raw_path_spec) != 0 && raw_path_spec[len(raw_path_spec)-1] != '/' {
		http.Redirect(w, r, path.Base(path_spec)+"/", http.StatusSeeOther)
		return
	}

	params["readme_filename"], params["readme"] = render_readme_at_tree(target)
	params["files"] = build_display_git_tree(target)

	err = templates.ExecuteTemplate(w, "repo_tree_dir", params)
	if err != nil {

		http.Error(w, "Error rendering template:: "+err.Error(), http.StatusInternalServerError)

		http.Error(w, "Error rendering template: "+err.Error(), http.StatusInternalServerError)

		return
	}
}