// Command doltsrht is the dolt.sr.ht service daemon: one process running three
// listeners.
//
//   - the web UI (chi) on the -b address (default localhost:5307), assembled on
//     the core-go server's AnonRouter with our own middleware group (config +
//     database + optional unified-login cookie) so anonymous browsing and public
//     clones keep working — we deliberately do NOT use core-go's default
//     middleware, whose auth.Middleware 401s any un-cookied request. The MCP
//     surface rides the same listener at /mcp, above the cookie plane and
//     outside web's same-origin group, because it is bearer-only
//     (docs/DESIGN.mcp.md §3).
//   - the remotesapi (gRPC ChunkStoreService + HTTP chunk data plane, one h2c
//     port) on [dolt.sr.ht]remotesapi-listen (default 127.0.0.1:5306).
//   - the CredentialsService.WhoAmI gRPC server for the `dolt login` keypair
//     flow on [dolt.sr.ht]credsapi-listen (default 127.0.0.1:5308).
//
// server.New runs crypto.InitCrypto, which requires [sr.ht]network-key and
// [webhooks]private-key; a missing key panics there. The remotesapi server is
// built before the web Config because the web store manager's Evict drives the
// remotesapi chunk-store cache.
package main

import (
	"context"
	"database/sql"
	"fmt"
	"log/slog"
	"net/http"
	"os"

	"github.com/go-chi/chi/v5"
	chimiddleware "github.com/go-chi/chi/v5/middleware"
	_ "github.com/lib/pq" // registers the "postgres" database/sql driver
	"github.com/vaughan0/go-ini"

	"go.bigb.es/auxilia/culpa"
	"go.bigb.es/auxilia/logrusbridge"
	"go.bigb.es/auxilia/scribe"

	"sourcecraft.dev/bigbes/sr-ht-core/config"
	"sourcecraft.dev/bigbes/sr-ht-core/database"
	"sourcecraft.dev/bigbes/sr-ht-core/server"

	"sourcecraft.dev/bigbes/sr-ht-ecore/chimw"
	"sourcecraft.dev/bigbes/sr-ht-ecore/instconf"

	"sourcecraft.dev/bigbes/sr-ht-dolt/authn"
	"sourcecraft.dev/bigbes/sr-ht-dolt/remoteapi"
	"sourcecraft.dev/bigbes/sr-ht-dolt/storage"
	"sourcecraft.dev/bigbes/sr-ht-dolt/web"
)

// serviceName is the SourceHut service identifier and config section name.
const serviceName = "dolt.sr.ht"

const (
	defaultWebAddr        = "localhost:5307"
	defaultReposRoot      = "/var/lib/dolt"
	defaultStaticDir      = "./static"
	defaultRemotesapiAddr = "127.0.0.1:5306"
	defaultCredsapiAddr   = "127.0.0.1:5308"
)

// storeManager satisfies web.StoreManager over the storage package and the
// remotesapi server's chunk-store cache. web never imports storage/ or
// remoteapi/; main is where the on-disk store lifecycle and the served cache are
// tied together, so a database deleted through the web UI both removes its
// on-disk store and evicts any handle the remotesapi server memoized.
type storeManager struct {
	cache *storage.Cache
}

var _ web.StoreManager = (*storeManager)(nil)

func (m *storeManager) InitStore(ctx context.Context, absPath, ownerName, ownerEmail string) error {
	return storage.InitStore(ctx, absPath, ownerName, ownerEmail)
}

func (m *storeManager) DeleteStore(ctx context.Context, root, absPath string) error {
	return storage.DeleteStore(ctx, root, absPath)
}

func (m *storeManager) Evict(diskPath string) error {
	return m.cache.Evict(diskPath)
}

// settings are the resolved [dolt.sr.ht] config values the daemon needs, split
// out from main so the required-key and defaulting logic is unit-testable
// without booting the process.
type settings struct {
	connString     string
	reposRoot      string
	staticDir      string
	remotesapiAddr string
	credsapiAddr   string
	// origin is the canonical external origin, [dolt.sr.ht]origin as
	// instconf.CanonicalOrigin spells it. It is what /mcp guards its Host header
	// with (mcpsrv.New), and it is kept whole rather than reduced to httpHost
	// below because that check wants the name and this one wants the URL.
	origin string
	// httpHost is the bare authority (host[:port]) of the external origin. It is
	// stamped into sealed chunk-download URLs and seeds the keypair-JWT audience.
	httpHost string
}

// resolveSettings reads the [dolt.sr.ht] section, applying defaults and failing
// on the keys that have no sensible default (connection-string and origin).
//
// Both gaps are reported together rather than one per boot. An operator filling
// in a fresh config.ini wants the whole list in front of them, not one key per
// restart, which is what instconf.Require is for.
func resolveSettings(conf ini.File) (settings, error) {
	if err := instconf.Require(conf,
		instconf.Need(serviceName, "connection-string"),
		instconf.Need(serviceName, "origin"),
	); err != nil {
		// A hint rather than a longer sentence: scribe prints it on its own
		// line, and what an operator meeting this needs is the keys to add, not
		// a restatement of the failure.
		return settings{}, culpa.WithHint(culpa.Wrap(err, "reading the config"),
			"origin is what places this service in every other service's nav")
	}

	// The authority and not the bare host: the port is part of what identifies
	// this endpoint, and https://x:8443 and https://x:9443 are two different
	// sealed-URL hosts and two different JWT audiences. "" here means the origin
	// is set but names no host — a scheme-less "dolt.example.org" is a path, not
	// a URL — which is a configuration error and not a reason to guess.
	origin := instconf.ExternalOrigin(conf, serviceName)
	host := instconf.OriginAuthority(origin)
	if host == "" {
		return settings{}, culpa.WithHint(
			culpa.New(fmt.Sprintf("[%s]origin names no host", serviceName)),
			"origin must be protocol://host, e.g. https://dolt.example.org")
	}

	return settings{
		connString:     config.GetString(conf, serviceName, "connection-string", ""),
		reposRoot:      config.GetString(conf, serviceName, "repos", defaultReposRoot),
		staticDir:      config.GetString(conf, serviceName, "static-dir", defaultStaticDir),
		remotesapiAddr: config.GetString(conf, serviceName, "remotesapi-listen", defaultRemotesapiAddr),
		credsapiAddr:   config.GetString(conf, serviceName, "credsapi-listen", defaultCredsapiAddr),
		origin:         origin,
		httpHost:       host,
	}, nil
}

func main() {
	conf := config.LoadConfig()

	// Before anything that can fail: everything below, and every library this
	// process links, reports through slog's default logger.
	setupLogging(conf)

	// server.New parses -b/-d/-m/-p and runs crypto.InitCrypto (needs
	// [sr.ht]network-key + [webhooks]private-key; missing keys panic here).
	// Pass the full os.Args: core-go's getopt skips argv[0] as the program name
	// itself (like every upstream sourcehut daemon). Passing os.Args[1:] makes
	// getopt swallow the first real flag (e.g. -b) as the program name, so the
	// web bind silently falls back to defaultWebAddr (localhost) — unreachable
	// from Traefik/other containers.
	srv := server.New(serviceName, defaultWebAddr, conf, os.Args)

	cfg, err := resolveSettings(conf)
	if err != nil {
		fatal("reading the configuration", err)
	}

	db, err := sql.Open("postgres", cfg.connString)
	if err != nil {
		fatal("opening the postgres pool", err)
	}

	// Build the remotesapi server first: its chunk-store cache backs the web
	// store manager's Evict.
	rapiConf := remoteapi.Config{
		Conf:            conf,
		DB:              db,
		ReposRoot:       cfg.reposRoot,
		ListenAddr:      cfg.remotesapiAddr,
		CredsListenAddr: cfg.credsapiAddr,
		HttpHost:        cfg.httpHost,
		// dolt's remotesrv takes a *logrus.Entry and nothing else. Bridged, so
		// that the half of this process serving clones and pushes reports
		// through the same handler, at the same level and behind the same masks
		// as the half we wrote.
		DoltLogger: logrusbridge.Entry(),
	}
	rsrv, err := remoteapi.New(rapiConf)
	if err != nil {
		fatal("building the remotesapi server", err)
	}
	csrv, err := remoteapi.NewCredServer(rapiConf)
	if err != nil {
		fatal("building the credentials server", err)
	}

	stores := &storeManager{cache: rsrv.Cache()}

	// The git-description mirror is wired only on an instance that has a
	// git.sr.ht to ask. web.Config documents a nil Git as "no mirroring", but
	// nothing used to produce one: core-go's client.Do walks the API-origin
	// ladder through config.GetAPI, which panics when it reaches the end, so an
	// instance without git.sr.ht met that as a stack trace on the first push
	// rather than as a description it simply did not copy.
	var git web.GitDescriber
	if _, ok := instconf.InternalAPIOrigin(conf, "git.sr.ht"); ok {
		git = web.GitDescriptionResolver{}
	} else {
		slog.Warn("no git.sr.ht API origin is configured; companion databases will not mirror their git twin's description",
			"component", "web", "keys", instconf.APIOriginKeys())
	}

	// The MCP surface, built before the router: its Host allowlist and its
	// credential plane come out of the config, so a wiring mistake in either
	// stops the boot rather than answering every agent 500 later.
	agents, err := newMCPServer(conf, cfg)
	if err != nil {
		fatal("building the mcp surface", err)
	}

	srv.AnonRouter().Group(func(r chi.Router) {
		if err := mountRoutes(r, surfaces{
			conf:   conf,
			db:     db,
			cfg:    cfg,
			stores: stores,
			git:    git,
			mcp:    agents,
		}); err != nil {
			fatal("mounting the web routes", err)
		}
	})

	// Start the two gRPC listeners; each blocks in Serve, so run them in
	// goroutines and let the web server's Run own the SIGINT lifecycle.
	go func() {
		if err := rsrv.Serve(); err != nil {
			fatal("serving the remotesapi", err)
		}
	}()
	go func() {
		if err := csrv.Serve(); err != nil {
			fatal("serving the credentials api", err)
		}
	}()

	slog.Info("listening",
		"remotesapi", cfg.remotesapiAddr,
		"credentials", cfg.credsapiAddr,
		"web", defaultWebAddr,
		"mcp", mcpRoute,
		"instance_tokens", tokensDescription(conf))

	// Blocks until SIGINT, then returns after draining the web listeners.
	srv.Run()

	// GracefulStop on the remotesapi server also closes every memoized chunk
	// store (its cache Close), so no separate storage cache Close is needed.
	slog.Info("stopping the grpc servers")
	rsrv.GracefulStop()
	csrv.GracefulStop()
}

// surfaces is everything mountRoutes needs to install the two things this
// listener serves. It is a struct rather than a parameter list so that the boot
// test assembles the daemon's own router — the one whose middleware order and
// mount points are the thing worth testing — without a Postgres, a store on disk
// or core-go's server.New.
type surfaces struct {
	conf   ini.File
	db     *sql.DB
	cfg    settings
	stores web.StoreManager
	git    web.GitDescriber
	mcp    http.Handler
}

// mountRoutes installs the web listener's surfaces on r: /mcp for agents, and
// everything a browser reaches under it.
//
// r must be a chi Group and not a bare router. server.New has already frozen the
// AnonRouter for direct middleware registration, and a Group is a fresh inline
// mux over the same routing tree — which is where middleware and routes can
// still be attached together.
func mountRoutes(r chi.Router, s surfaces) error {
	// RequestID and RealIP first: the request line below carries the id and the
	// viewer's address, and neither exists until these have run.
	r.Use(chimiddleware.RequestID, chimiddleware.RealIP)
	// The request line as a slog record rather than chi's colourised line on
	// stdout — the one line this daemon emitted that was neither structured nor
	// on stderr, so an operator grepping the journal for a request id found every
	// panic and none of the requests. It goes outermost, above the panic guards,
	// so that the status it reports is the one that actually went out.
	r.Use(chimw.RequestLogger(chimw.SlogFormatter{}))
	r.Use(chimiddleware.Recoverer)
	r.Use(config.Middleware(s.conf, serviceName), database.Middleware(s.db))

	// The MCP surface, and three things decide where this line is
	// (docs/DESIGN.mcp.md §3, §4.1):
	//
	// Before web.Register, because web claims "/" and wraps everything it mounts
	// in the same-origin CSRF group. /mcp is a bearer surface: no cookie, no
	// Origin header, no browser — the guard would refuse every call it ever
	// receives.
	//
	// Before the cookie middleware below, because the unified-login cookie is the
	// web UI's plane and this one accepts exactly one credential. A chi group
	// takes its middleware chain when its route is registered, so what is
	// installed after this line does not reach /mcp; that is the point of the
	// line's position and not an accident of it.
	//
	// In a Group of its own rather than a bare r.Handle here, because
	// web.Register installs middleware of its own on the router it is handed
	// (web/router.go's mount), and chi refuses a r.Use once any route exists on
	// that mux — "all middlewares must be defined before routes on a mux" is a
	// panic, so registering /mcp directly on r would fail this daemon's boot.
	//
	// Handle and not Mount: the streamable transport serves that exact path.
	// Mount would rewrite the routing path to the empty remainder and would also
	// claim /mcp/*, a subtree this surface does not serve.
	r.Group(func(r chi.Router) {
		r.Handle(mcpRoute, s.mcp)
	})

	r.Use(authn.OptionalCookieMiddleware()) // never 401s; anonymous stays anonymous

	return web.Register(r, web.Config{
		Conf:      s.conf,
		ReposRoot: s.cfg.reposRoot,
		StaticDir: s.cfg.staticDir,
		Stores:    s.stores,
		Repos:     web.DBAdapter{},
		Browse:    web.BrowseAdapter{},
		Users:     web.MetaUserResolver{},
		Git:       s.git,
		RepoDiskPath: func(owner, name string) string {
			return storage.RepoDiskPath(s.cfg.reposRoot, owner, name)
		},
	})
}

// fatal reports a startup failure and ends the process. slog has no Fatal, on
// the argument that a logging call should not decide a program's lifetime; this
// is the one place in this binary that wants both, so it is written once here
// rather than as an Error/Exit pair at every call site.
func fatal(doing string, err error) {
	slog.Error(doing+" failed", scribe.Err(err))
	os.Exit(1)
}