// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>

package main

import (
	"errors"
	"net/http"
	"strconv"
	"strings"

	"github.com/jackc/pgx/v5"
	"go.lindenii.runxiyu.org/lindenii-common/clog"
)

type forgeHTTPRouter struct{}

// ServeHTTP handles all incoming HTTP requests and routes them to the correct
// location.
//
// TODO: This function is way too large.
func (router *forgeHTTPRouter) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
	var remoteAddr string
	if config.HTTP.ReverseProxy {
		remoteAddrs, ok := request.Header["X-Forwarded-For"]
		if ok && len(remoteAddrs) == 1 {
			remoteAddr = remoteAddrs[0]
		} else {
			remoteAddr = request.RemoteAddr
		}
	} else {
		remoteAddr = request.RemoteAddr
	}
	clog.Info("Incoming HTTP: " + remoteAddr + " " + request.Method + " " + request.RequestURI)

	var segments []string
	var err error
	var sepIndex int
	params := make(map[string]any)

	if segments, _, err = parseReqURI(request.RequestURI); err != nil {
		errorPage400(writer, params, "Error parsing request URI: "+err.Error())
		return
	}
	dirMode := false
	if segments[len(segments)-1] == "" {
		dirMode = true
		segments = segments[:len(segments)-1]
	}

	params["url_segments"] = segments
	params["dir_mode"] = dirMode
	params["global"] = globalData
	var userID int // 0 for none
	userID, params["username"], err = getUserFromRequest(request)
	params["user_id"] = userID
	if err != nil && !errors.Is(err, http.ErrNoCookie) && !errors.Is(err, pgx.ErrNoRows) {
		errorPage500(writer, params, "Error getting user info from request: "+err.Error())
		return
	}

	if userID == 0 {
		params["user_id_string"] = ""
	} else {
		params["user_id_string"] = strconv.Itoa(userID)
	}

	if len(segments) == 0 {
		httpHandleIndex(writer, request, params)
		return
	}

	if segments[0] == ":" {

	if segments[0] == "-" {

		if len(segments) < 2 {
			errorPage404(writer, params)
			return
		} else if len(segments) == 2 && redirectDir(writer, request) {
			return
		}

		switch segments[1] {
		case "man":
			manHandler.ServeHTTP(writer, request)
			return
		case "static":
			staticHandler.ServeHTTP(writer, request)
			return
		case "source":
			sourceHandler.ServeHTTP(writer, request)
			return
		}
	}

	if segments[0] == ":" {

	if segments[0] == "-" {

		switch segments[1] {
		case "login":
			httpHandleLogin(writer, request, params)
			return
		case "users":
			httpHandleUsers(writer, request, params)
			return
		case "gc":
			httpHandleGC(writer, request, params)
			return
		default:
			errorPage404(writer, params)
			return
		}
	}

	sepIndex = -1
	for i, part := range segments {

		if part == ":" {

		if part == "-" {

			sepIndex = i
			break
		}
	}

	params["separator_index"] = sepIndex

	var groupPath []string
	var moduleType string
	var moduleName string

	if sepIndex > 0 {
		groupPath = segments[:sepIndex]
	} else {
		groupPath = segments
	}
	params["group_path"] = groupPath

	switch {
	case sepIndex == -1:
		if redirectDir(writer, request) {
			return
		}
		httpHandleGroupIndex(writer, request, params)
	case len(segments) == sepIndex+1:
		errorPage404(writer, params)
		return
	case len(segments) == sepIndex+2:
		errorPage404(writer, params)
		return
	default:
		moduleType = segments[sepIndex+1]
		moduleName = segments[sepIndex+2]
		switch moduleType {
		case "repos":
			params["repo_name"] = moduleName

			if len(segments) > sepIndex+3 {
				switch segments[sepIndex+3] {
				case "info":
					if err = httpHandleRepoInfo(writer, request, params); err != nil {
						errorPage500(writer, params, err.Error())
					}
					return
				case "git-upload-pack":
					if err = httpHandleUploadPack(writer, request, params); err != nil {
						errorPage500(writer, params, err.Error())
					}
					return
				}
			}

			if params["ref_type"], params["ref_name"], err = getParamRefTypeName(request); err != nil {
				if errors.Is(err, errNoRefSpec) {
					params["ref_type"] = ""
				} else {
					errorPage500(writer, params, "Error querying ref type: "+err.Error())
					return
				}
			}

			// TODO: subgroups

			if params["repo"], params["repo_description"], params["repo_id"], err = openRepo(request.Context(), groupPath, moduleName); err != nil {
				errorPage500(writer, params, "Error opening repo: "+err.Error())
				return
			}

			if len(segments) == sepIndex+3 {
				if redirectDir(writer, request) {
					return
				}
				httpHandleRepoIndex(writer, request, params)
				return
			}

			repoFeature := segments[sepIndex+3]
			switch repoFeature {
			case "tree":
				if anyContain(segments[sepIndex+4:], "/") {
					errorPage400(writer, params, "Repo tree paths may not contain slashes in any segments")
					return
				}
				if dirMode {
					params["rest"] = strings.Join(segments[sepIndex+4:], "/") + "/"
				} else {
					params["rest"] = strings.Join(segments[sepIndex+4:], "/")
				}
				if len(segments) < sepIndex+5 && redirectDir(writer, request) {
					return
				}
				httpHandleRepoTree(writer, request, params)
			case "branches":
				if redirectDir(writer, request) {
					return
				}
				httpHandleRepoBranches(writer, request, params)
				return
			case "raw":
				if anyContain(segments[sepIndex+4:], "/") {
					errorPage400(writer, params, "Repo tree paths may not contain slashes in any segments")
					return
				}
				if dirMode {
					params["rest"] = strings.Join(segments[sepIndex+4:], "/") + "/"
				} else {
					params["rest"] = strings.Join(segments[sepIndex+4:], "/")
				}
				if len(segments) < sepIndex+5 && redirectDir(writer, request) {
					return
				}
				httpHandleRepoRaw(writer, request, params)
			case "log":
				if len(segments) > sepIndex+4 {
					errorPage400(writer, params, "Too many parameters")
					return
				}
				if redirectDir(writer, request) {
					return
				}
				httpHandleRepoLog(writer, request, params)
			case "commit":
				if len(segments) != sepIndex+5 {
					errorPage400(writer, params, "Incorrect number of parameters")
					return
				}
				if redirectNoDir(writer, request) {
					return
				}
				params["commit_id"] = segments[sepIndex+4]
				httpHandleRepoCommit(writer, request, params)
			case "contrib":
				if redirectDir(writer, request) {
					return
				}
				switch len(segments) {
				case sepIndex + 4:
					httpHandleRepoContribIndex(writer, request, params)
				case sepIndex + 5:
					params["mr_id"] = segments[sepIndex+4]
					httpHandleRepoContribOne(writer, request, params)
				default:
					errorPage400(writer, params, "Too many parameters")
				}
			default:
				errorPage404(writer, params)
				return
			}
		default:
			errorPage404(writer, params)
			return
		}
	}
}

// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
// SPDX-FileCopyrightText: Copyright (c) 2024 Robin Jarry <robin@jarry.cc>

package main

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net"
	"strings"
	"time"

	"github.com/emersion/go-message"
	"github.com/emersion/go-smtp"
)

type lmtpHandler struct{}

type lmtpSession struct {
	from string
	to   []string
}

func (session *lmtpSession) Reset() {
	session.from = ""
	session.to = nil
}

func (session *lmtpSession) Logout() error {
	return nil
}

func (session *lmtpSession) AuthPlain(_, _ string) error {
	return nil
}

func (session *lmtpSession) Mail(from string, _ *smtp.MailOptions) error {
	session.from = from
	return nil
}

func (session *lmtpSession) Rcpt(to string, _ *smtp.RcptOptions) error {
	session.to = append(session.to, to)
	return nil
}

func (*lmtpHandler) NewSession(_ *smtp.Conn) (smtp.Session, error) {
	session := &lmtpSession{}
	return session, nil
}

func serveLMTP(listener net.Listener) error {
	smtpServer := smtp.NewServer(&lmtpHandler{})
	smtpServer.LMTP = true
	smtpServer.Domain = config.LMTP.Domain
	smtpServer.Addr = config.LMTP.Socket
	smtpServer.WriteTimeout = time.Duration(config.LMTP.WriteTimeout) * time.Second
	smtpServer.ReadTimeout = time.Duration(config.LMTP.ReadTimeout) * time.Second
	smtpServer.EnableSMTPUTF8 = true
	return smtpServer.Serve(listener)
}

func (session *lmtpSession) Data(r io.Reader) error {
	var (
		email *message.Entity
		from  string
		to    []string
		err   error
		buf   bytes.Buffer
		data  []byte
		n     int64
	)

	n, err = io.CopyN(&buf, r, config.LMTP.MaxSize)
	switch {
	case n == config.LMTP.MaxSize:
		err = errors.New("Message too big.")
		// drain whatever is left in the pipe
		_, _ = io.Copy(io.Discard, r)
		goto end
	case errors.Is(err, io.EOF):
		// message was smaller than max size
		break
	case err != nil:
		goto end
	}

	data = buf.Bytes()

	email, err = message.Read(bytes.NewReader(data))
	if err != nil && message.IsUnknownCharset(err) {
		goto end
	}

	switch strings.ToLower(email.Header.Get("Auto-Submitted")) {
	case "auto-generated", "auto-replied":
		// Disregard automatic emails like OOO replies.
		slog.Info("ignoring automatic message",
			"from", session.from,
			"to", strings.Join(session.to, ","),
			"message-id", email.Header.Get("Message-Id"),
			"subject", email.Header.Get("Subject"),
		)
		goto end
	}

	slog.Info("message received",
		"from", session.from,
		"to", strings.Join(session.to, ","),
		"message-id", email.Header.Get("Message-Id"),
		"subject", email.Header.Get("Subject"),
	)

	// Make local copies of the values before to ensure the references will
	// still be valid when the task is run.
	from = session.from
	to = session.to

	_ = from

	for _, to := range to {
		if !strings.HasSuffix(to, "@"+config.LMTP.Domain) {
			continue
		}
		localPart := to[:len(to)-len("@"+config.LMTP.Domain)]
		segments, err := pathToSegments(localPart)
		if err != nil {
			// TODO: Should the entire email fail or should we just
			// notify them out of band?
			err = fmt.Errorf("cannot parse path: %w", err)
			goto end
		}
		sepIndex := -1
		for i, part := range segments {

			if part == ":" {

			if part == "-" {

				sepIndex = i
				break
			}
		}
		if segments[len(segments)-1] == "" {
			segments = segments[:len(segments)-1] // We don't care about dir or not.
		}
		if sepIndex == -1 || len(segments) <= sepIndex+2 {
			err = errors.New("illegal path")
			goto end
		}

		groupPath := segments[:sepIndex]
		moduleType := segments[sepIndex+1]
		moduleName := segments[sepIndex+2]
		switch moduleType {
		case "repos":
			err = lmtpHandlePatch(groupPath, moduleName, email)
			if err != nil {
				goto end
			}
		default:
			err = fmt.Errorf("Emailing any endpoint other than repositories, is not supported yet.") // TODO
			goto end
		}
	}

end:
	session.to = nil
	session.from = ""
	return err
}

// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"net/url"

	"go.lindenii.runxiyu.org/lindenii-common/ansiec"
)

var errIllegalSSHRepoPath = errors.New("illegal SSH repo path")

// getRepoInfo2 also fetches repo information... it should be deprecated and
// implemented in individual handlers.
func getRepoInfo2(ctx context.Context, sshPath, sshPubkey string) (groupPath []string, repoName string, repoID int, repoPath string, directAccess bool, contribReq, userType string, userID int, err error) {
	var segments []string
	var sepIndex int
	var moduleType, moduleName string

	segments, err = pathToSegments(sshPath)
	if err != nil {
		return
	}

	for i, segment := range segments {
		var err error
		segments[i], err = url.PathUnescape(segment)
		if err != nil {
			return []string{}, "", 0, "", false, "", "", 0, err
		}
	}

	if segments[0] == ":" {

	if segments[0] == "-" {

		return []string{}, "", 0, "", false, "", "", 0, errIllegalSSHRepoPath
	}

	sepIndex = -1
	for i, part := range segments {

		if part == ":" {

		if part == "-" {

			sepIndex = i
			break
		}
	}
	if segments[len(segments)-1] == "" {
		segments = segments[:len(segments)-1]
	}

	switch {
	case sepIndex == -1:
		return []string{}, "", 0, "", false, "", "", 0, errIllegalSSHRepoPath
	case len(segments) <= sepIndex+2:
		return []string{}, "", 0, "", false, "", "", 0, errIllegalSSHRepoPath
	}

	groupPath = segments[:sepIndex]
	moduleType = segments[sepIndex+1]
	moduleName = segments[sepIndex+2]
	repoName = moduleName
	switch moduleType {
	case "repos":
		_1, _2, _3, _4, _5, _6, _7 := getRepoInfo(ctx, groupPath, moduleName, sshPubkey)
		return groupPath, repoName, _1, _2, _3, _4, _5, _6, _7
	default:
		return []string{}, "", 0, "", false, "", "", 0, errIllegalSSHRepoPath
	}
}

// writeRedError is a helper function that basically does a Fprintf but makes
// the entire thing red, in terms of ANSI escape sequences. It's useful when
// producing error messages on SSH connections.
func writeRedError(w io.Writer, format string, args ...any) {
	fmt.Fprintln(w, ansiec.Red+fmt.Sprintf(format, args...)+ansiec.Reset)
}