// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileContributor: Runxi Yu <https://runxiyu.org>

package main

import (
	"bufio"
	"context"
	"errors"
	"os"

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

var database *pgxpool.Pool

var config struct {
	HTTP struct {
		Net          string `scfg:"net"`
		Addr         string `scfg:"addr"`
		CookieExpiry int    `scfg:"cookie_expiry"`
		Root         string `scfg:"root"`
		ReadTimeout  uint   `scfg:"read_timeout"`
		WriteTimeout uint   `scfg:"write_timeout"`
		IdleTimeout  uint   `scfg:"idle_timeout"`

		ReverseProxy bool   `scfg:"reverse_proxy"`

	} `scfg:"http"`
	Hooks struct {
		Socket string `scfg:"socket"`
		Execs  string `scfg:"execs"`
	} `scfg:"hooks"`
	Git struct {
		RepoDir string `scfg:"repo_dir"`
	} `scfg:"git"`
	SSH struct {
		Net  string `scfg:"net"`
		Addr string `scfg:"addr"`
		Key  string `scfg:"key"`
		Root string `scfg:"root"`
	} `scfg:"ssh"`
	IRC struct {
		Net   string `scfg:"net"`
		Addr  string `scfg:"addr"`
		TLS   bool   `scfg:"tls"`
		SendQ uint   `scfg:"sendq"`
		Nick  string `scfg:"nick"`
		User  string `scfg:"user"`
		Gecos string `scfg:"gecos"`
	} `scfg:"irc"`
	General struct {
		Title string `scfg:"title"`
	} `scfg:"general"`
	DB struct {
		Type string `scfg:"type"`
		Conn string `scfg:"conn"`
	} `scfg:"db"`
}

func loadConfig(path string) (err error) {
	var configFile *os.File
	var decoder *scfg.Decoder

	if configFile, err = os.Open(path); err != nil {
		return err
	}
	defer configFile.Close()

	decoder = scfg.NewDecoder(bufio.NewReader(configFile))
	if err = decoder.Decode(&config); err != nil {
		return err
	}

	if config.DB.Type != "postgres" {
		return errors.New("unsupported database type")
	}

	if database, err = pgxpool.New(context.Background(), config.DB.Conn); err != nil {
		return err
	}

	globalData["forge_title"] = config.General.Title

	return nil
}

http {
	# What network transport should we listen on?
	# Examples: tcp tcp4 tcp6 unix
	net tcp

	# What address to listen on?
	# Examples for net tcp*: 127.0.0.1:8080 :80
	# Example for unix: /var/run/lindenii/forge/http.sock
	addr /var/run/lindenii/forge/http.sock

	# How many seconds should cookies be remembered before they are purged?
	cookie_expiry 604800

	# What is the canonical URL of the web root?
	root https://forge.example.org

	# General HTTP server context timeout settings. It's recommended to
	# set them slightly higher than usual as Git operations over large
	# repos may take a long time.

	read_timeout 120

	write_timeout 120

	write_timeout 1800

	idle_timeout 120

	# Are we running behind a reverse proxy? If so, we will trust
	# X-Forwarded-For headers.
	reverse_proxy true

}

irc {
	tls true
	net tcp
	addr irc.runxiyu.org:6697
	sendq 6000
	nick forge-test
	user forge
	gecos "Lindenii Forge Test"
}

git {
	repo_dir /var/lib/lindenii/forge/repos
}

ssh {
	# What network transport should we listen on?
	# This should be "tcp" in almost all cases.
	net tcp

	# What address to listen on?
	addr :22

	# What is the path to the SSH host key? Generate it with ssh-keygen.
	# The key must have an empty password.
	key /etc/lindenii/ssh_host_ed25519_key

	# What is the canonical SSH URL?
	root ssh://forge.example.org
}

general {
	title "Test Forge"
}

db {
	# What type of database are we connecting to?
	# Currently only "postgres" is supported.
	type postgres

	# What is the connection string?
	conn postgresql:///lindenii-forge?host=/var/run/postgresql
}

hooks {
	# On which UNIX domain socket should we listen for hook callbacks on?
	socket /var/run/lindenii/forge/hooks.sock

	# Where should hook executables be put?
	execs /usr/libexec/lindenii/forge/hooks
}

// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileContributor: 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{}

func (router *forgeHTTPRouter) ServeHTTP(writer http.ResponseWriter, request *http.Request) {

	clog.Info("Incoming HTTP: " + request.RemoteAddr + " " + request.Method + " " + request.RequestURI)

	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 {
		http.Error(writer, err.Error(), http.StatusBadRequest)
		return
	}
	if segments[len(segments)-1] == "" {
		segments = segments[:len(segments)-1]
	}

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

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

	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 == ":" {
			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
				}
				params["rest"] = strings.Join(segments[sepIndex+4:], "/")
				if len(segments) < sepIndex+5 && redirectDir(writer, request) {
					return
				}
				httpHandleRepoTree(writer, request, params)
			case "raw":
				if anyContain(segments[sepIndex+4:], "/") {
					errorPage400(writer, params, "Repo tree paths may not contain slashes in any segments")
					return
				}
				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 {
					http.Error(writer, "Too many parameters", http.StatusBadRequest)
					return
				}
				if redirectDir(writer, request) {
					return
				}
				httpHandleRepoLog(writer, request, params)
			case "commit":
				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:
					http.Error(writer, "Too many parameters", http.StatusBadRequest)
				}
			default:
				errorPage404(writer, params)
				return
			}
		default:
			errorPage404(writer, params)
			return
		}
	}
}