package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/spf13/cobra"

	"github.com/runbear-io/beardrive/internal/config"
	"github.com/runbear-io/beardrive/internal/remote"
	"github.com/runbear-io/beardrive/internal/webapp"
)

// webConfig mirrors the serve command's flags so a server can be configured
// from a file (bdrive serve -c config.json). Explicitly-passed flags win over
// file values.
type webConfig struct {
	Remote     string `json:"remote,omitempty"`
	Dir        string `json:"dir,omitempty"`
	Addr       string `json:"addr,omitempty"`
	Volume     string `json:"volume,omitempty"`
	Refresh    string `json:"refresh,omitempty"` // duration, e.g. "10s"
	Upload     *bool  `json:"upload,omitempty"`
	UploadTTL  string `json:"upload_ttl,omitempty"`  // duration, e.g. "15m"
	ProjectsDB string `json:"projects_db,omitempty"` // hub project registry path
	ShareRPM   int    `json:"share_rpm,omitempty"`   // per-IP rate on /s/* (default 120/min)
	// TrustProxy makes the rate limiters read the client address from
	// X-Forwarded-For sent by ANY peer. Usually unnecessary: a proxy that
	// reaches the hub over loopback or a private network is trusted with no
	// configuration. Set it only for a proxy on a PUBLIC address — on a
	// directly-reachable hub the header is client-supplied, and trusting it
	// lets one connection get a fresh bucket per request, which disables the
	// share limiter and the login brute-force limiter alike.
	TrustProxy bool `json:"trust_proxy,omitempty"`
	// Auth tunes the hub's (always-on) authentication; hubs require
	// sign-in unconditionally, only these knobs are optional.
	Auth *struct {
		AllowSignup         *bool    `json:"allow_signup,omitempty"`         // default true
		UsersDB             string   `json:"users_db,omitempty"`             // default $BDRIVE_HOME/auth.json
		AllowedDomains      []string `json:"allowed_domains,omitempty"`      // signup email must match one (e.g. ["runbear.io"])
		RequireVerification *bool    `json:"require_verification,omitempty"` // new accounts verify email before activation
		RequireApproval     *bool    `json:"require_approval,omitempty"`     // new accounts await admin approval
		Admins              []string `json:"admins,omitempty"`               // hub admin emails (approve users, govern shares)
		Brand               string   `json:"brand,omitempty"`                // name shown on the sign-in page
		BaseURL             string   `json:"base_url,omitempty"`             // public origin used for MAILED links (never the request's Host)
		SMTP                *struct {
			Host string `json:"host"`
			Port int    `json:"port"`
			User string `json:"user,omitempty"`
			Pass string `json:"pass,omitempty"`
			From string `json:"from,omitempty"`
		} `json:"smtp,omitempty"`
	} `json:"auth,omitempty"`
	// Database selects where hub metadata (accounts, projects, orgs, invites,
	// shares, devices) lives. Default "file" (JSON under BDRIVE_HOME). Blobs
	// and journals always stay in the object store, never the database.
	Database *struct {
		Driver string `json:"driver,omitempty"` // file (default) | sqlite | postgres
		DSN    string `json:"dsn,omitempty"`    // sqlite file path, or a Postgres/Supabase URL
	} `json:"database,omitempty"`
	// Reads tunes read telemetry (the heat API): aggregate view counts per
	// file, split human/agent/share. On by default in hub mode; counts only,
	// no reader identities in any API.
	Reads *struct {
		Enabled       *bool `json:"enabled,omitempty"`        // default true
		RetentionDays int   `json:"retention_days,omitempty"` // default 400; older days fold into all-time
		// SessionRetentionDays bounds the per-session read detail behind
		// History's run cards (which files an agent session read). Default
		// 30, and deliberately much shorter than RetentionDays: this is
		// event-shaped rather than aggregate, and rows past it are deleted,
		// which changes no heat total.
		SessionRetentionDays int `json:"session_retention_days,omitempty"`
	} `json:"reads,omitempty"`
}

func loadWebConfig(path string) (webConfig, error) {
	var c webConfig
	data, err := os.ReadFile(path)
	if err != nil {
		return c, err
	}
	dec := json.NewDecoder(bytes.NewReader(data))
	dec.DisallowUnknownFields()
	if err := dec.Decode(&c); err != nil {
		return c, fmt.Errorf("parse %s: %w", path, err)
	}
	return c, nil
}

func webCmd() *cobra.Command {
	var remoteURL, dir, volume string
	var addr, configPath, projectsDB string
	var refresh, uploadTTL time.Duration
	var upload bool
	var cfg webConfig
	c := &cobra.Command{
		Use:     "serve [folder | storage-root-url]",
		Aliases: []string{"web"},
		Short:   "Serve the bdrive web server: viewer, uploads, and sync hub",
		Long: `Serve the bdrive web server: browse folders and files, read rendered
markdown (Obsidian-style, including [[wikilinks]]), and download any file.

Two modes:

  - a local folder, served straight from disk (the default — on a mounted
    folder the daemon keeps it fresh, so this is the simplest viewer);
  - a hub: point it at an object-storage root and it hosts many projects,
    each stored under its own prefix, managed by a file-backed project
    registry. Client devices run "bdrive login <this server>" once, then
    "bdrive init" per project, and sync whole folders through it without
    ever seeing the storage location or holding cloud credentials.

The server is read-only unless --upload is set. With uploads on, content
travels directly between clients and the object store through short-lived
presigned URLs when the backend supports it (S3, GCS with signing
credentials); otherwise it is relayed through this server.`,
		Example: `  bdrive serve                          # serve the current directory
  bdrive serve ./notes                  # serve a folder
  bdrive serve -c config.json           # everything from a config file
  bdrive serve s3://bucket/root --upload  # multi-project sync hub

  bdrive web                            # deprecated alias for "bdrive serve"`,
		Args: cobra.MaximumNArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			// Config file first; flags that were explicitly passed override
			// its values.
			if configPath != "" {
				c, err := loadWebConfig(configPath)
				if err != nil {
					return err
				}
				cfg = c
				set := cmd.Flags().Changed
				if c.Remote != "" && !set("remote") {
					remoteURL = c.Remote
				}
				if c.Dir != "" && !set("dir") {
					dir = c.Dir
				}
				if c.Addr != "" && !set("addr") {
					addr = c.Addr
				}
				if c.Volume != "" && !set("volume") {
					volume = c.Volume
				}
				if c.Upload != nil && !set("upload") {
					upload = *c.Upload
				}
				if c.Refresh != "" && !set("refresh") {
					d, err := time.ParseDuration(c.Refresh)
					if err != nil {
						return fmt.Errorf("config refresh: %w", err)
					}
					refresh = d
				}
				if c.UploadTTL != "" && !set("upload-ttl") {
					d, err := time.ParseDuration(c.UploadTTL)
					if err != nil {
						return fmt.Errorf("config upload_ttl: %w", err)
					}
					uploadTTL = d
				}
				if c.ProjectsDB != "" && !set("projects-db") {
					projectsDB = c.ProjectsDB
				}
			}
			// Positional argument: a URL selects remote mode, anything else
			// is a folder. With nothing specified, serve the current dir.
			if remoteURL == "" && dir == "" && len(args) > 0 {
				if strings.Contains(args[0], "://") {
					remoteURL = args[0]
				} else {
					dir = args[0]
				}
			}
			if remoteURL != "" && dir != "" {
				return fmt.Errorf("--remote and --dir are mutually exclusive")
			}
			if remoteURL == "" && dir == "" {
				dir = "."
			}
			// A config that asks for gating this mode cannot provide is
			// refused, not silently honoured in part. The whole auth block —
			// allowed_domains, require_approval, allow_signup, admins — is
			// built only in the hub branch, so with a `dir` the operator got a
			// server anyone can read and a config file that said otherwise.
			// Same posture as ValidateSignupPolicy, which exists for exactly
			// this and lives inside the branch that never runs here.
			if dir != "" && cfg.Auth != nil {
				return fmt.Errorf("the `auth` block configures a hub's sign-in and a `dir` selects " +
					"the single-volume viewer, which is auth-free by design: remove one of them " +
					"(use `remote:` to run a hub)")
			}

			srv := &webapp.Server{
				Refresh:    refresh,
				Upload:     webapp.UploadConfig{Enabled: upload, TTL: uploadTTL},
				ShareRPM:   cfg.ShareRPM,
				TrustProxy: cfg.TrustProxy,
			}
			var display string
			var meta webapp.MetaStore // hub metadata store; nil means the file backend
			if dir != "" {
				// Single-volume viewer over a plain folder.
				abs, err := filepath.Abs(dir)
				if err != nil {
					return err
				}
				if fi, err := os.Stat(abs); err != nil || !fi.IsDir() {
					return fmt.Errorf("%s is not a directory", abs)
				}
				srv.Source = &webapp.DirSource{Root: abs}
				srv.Volume = filepath.Base(abs)
				display = abs
			} else {
				// Hub: many projects on one storage root.
				be, err := remote.Open(cmd.Context(), remoteURL)
				if err != nil {
					return err
				}
				defer be.Close()
				if projectsDB == "" {
					home, err := config.Home()
					if err != nil {
						return err
					}
					projectsDB = filepath.Join(home, "projects.json")
				}
				// Pick the metadata backend: file (default) or a SQL database
				// (sqlite locally, Postgres/Supabase in production).
				if cfg.Database != nil {
					switch cfg.Database.Driver {
					case "", "file":
					case "sqlite", "postgres", "pgx":
						drv := cfg.Database.Driver
						if drv == "postgres" {
							drv = "pgx"
						}
						meta, err = webapp.OpenSQLStore(drv, cfg.Database.DSN)
						if err != nil {
							return fmt.Errorf("open database: %w", err)
						}
						defer meta.Close()
					default:
						return fmt.Errorf("unknown database driver %q (use file, sqlite, or postgres)", cfg.Database.Driver)
					}
				}
				var db *webapp.ProjectDB
				if meta != nil {
					db, err = webapp.NewProjectDB(meta.Projects())
				} else {
					db, err = webapp.OpenProjectDB(projectsDB)
				}
				if err != nil {
					return fmt.Errorf("open project registry: %w", err)
				}
				dev, err := config.LoadDevice()
				if err != nil {
					return fmt.Errorf("load device identity: %w", err)
				}
				srv.Root = be
				srv.Projects = db
				srv.Device = webapp.Identity{ID: dev.ID, Name: dev.Name, Author: dev.Author}
				// Display name only — and it goes out in /api/config, which is
				// readable anonymously, so it must not be derived from the
				// storage URL: on s3://acme-prod-drive that named the bucket
				// to the whole internet. `--volume` / `volume:` stays the one
				// way an operator puts a storage-flavoured string on the wire.
				srv.Volume = "BearDrive"
				if meta != nil {
					display = remoteURL
				} else {
					display = remoteURL + " (projects: " + projectsDB + ")"
				}
			}
			if volume != "" {
				srv.Volume = volume
			}

			// Hubs always require sign-in: every op needs a real account
			// behind it (history, device registry). The plain-folder viewer
			// stays auth-free.
			if srv.Root != nil {
				usersDB := ""
				// Invite-only by default: a fresh hub doesn't accept self-signup
				// until an admin opts in (with a gate). Owners onboard people
				// with /join/<token> invite links.
				allowSignup := false
				var mail *webapp.Mailer
				if cfg.Auth != nil {
					usersDB = cfg.Auth.UsersDB
					if cfg.Auth.AllowSignup != nil {
						allowSignup = *cfg.Auth.AllowSignup
					}
					if cfg.Auth.SMTP != nil {
						mail = &webapp.Mailer{
							Host: cfg.Auth.SMTP.Host, Port: cfg.Auth.SMTP.Port,
							User: cfg.Auth.SMTP.User, Pass: cfg.Auth.SMTP.Pass,
							From: cfg.Auth.SMTP.From,
						}
					}
				}
				home, err := config.Home()
				if err != nil {
					return err
				}
				if usersDB == "" {
					usersDB = filepath.Join(home, "auth.json")
				}
				var auth *webapp.BuiltinAuth
				if meta != nil {
					auth, err = webapp.NewBuiltinAuth(meta.Accounts(), allowSignup, mail)
				} else {
					auth, err = webapp.OpenBuiltinAuth(usersDB, allowSignup, mail)
				}
				if err != nil {
					return fmt.Errorf("open account registry: %w", err)
				}
				if cfg.Auth != nil {
					auth.AllowedDomains = cfg.Auth.AllowedDomains
					// Toggles: an explicit config value pins the setting each
					// boot; otherwise the UI-saved policy (loaded from auth.json)
					// stands.
					if cfg.Auth.RequireVerification != nil {
						auth.RequireVerification = *cfg.Auth.RequireVerification
					}
					if cfg.Auth.RequireApproval != nil {
						auth.RequireApproval = *cfg.Auth.RequireApproval
					}
					auth.Brand = cfg.Auth.Brand
					auth.BaseURL = cfg.Auth.BaseURL
					if len(cfg.Auth.Admins) > 0 {
						auth.Admins = make(map[string]bool, len(cfg.Auth.Admins))
						for _, e := range cfg.Auth.Admins {
							auth.Admins[strings.ToLower(strings.TrimSpace(e))] = true
						}
					}
				}
				// Refuse to boot an incoherent signup posture (open with no
				// gate, or verification without a mailer) rather than silently
				// leaving the door open.
				if err := auth.ValidateSignupPolicy(); err != nil {
					return err
				}
				srv.Auth = auth
				var orgs *webapp.OrgDB
				if meta != nil {
					orgs, err = webapp.NewOrgDB(meta.Orgs())
				} else {
					orgs, err = webapp.OpenOrgDB(filepath.Join(filepath.Dir(projectsDB), "orgs.json"))
				}
				if err != nil {
					return fmt.Errorf("open org registry: %w", err)
				}
				srv.Dir = webapp.LocalDirectory{OrgDB: orgs}
				// Invite links can bootstrap an account on an invite-only hub.
				auth.InviteValid = orgs.ValidInvite
				// A hub that predates organizations: sweep its projects into
				// a default org so it keeps working with zero manual steps.
				if err := webapp.MigrateOrgs(srv.Projects, orgs, auth.Accounts()); err != nil {
					return fmt.Errorf("migrate projects into orgs: %w", err)
				}
				var devices *webapp.DeviceRegistry
				if meta != nil {
					devices, err = webapp.NewDeviceRegistry(meta.Devices())
				} else {
					devices, err = webapp.OpenDeviceRegistry(filepath.Join(filepath.Dir(projectsDB), "devices.json"))
				}
				if err != nil {
					return fmt.Errorf("open device registry: %w", err)
				}
				srv.Devices = devices
				var shares *webapp.ShareDB
				if meta != nil {
					shares, err = webapp.NewShareDB(meta.Shares())
				} else {
					shares, err = webapp.OpenShareDB(filepath.Join(filepath.Dir(projectsDB), "shares.json"))
				}
				if err != nil {
					return fmt.Errorf("open share registry: %w", err)
				}
				srv.Shares = shares
				readsOn, retention, sessRetention := true, 0, 0
				if cfg.Reads != nil {
					if cfg.Reads.Enabled != nil {
						readsOn = *cfg.Reads.Enabled
					}
					retention = cfg.Reads.RetentionDays
					sessRetention = cfg.Reads.SessionRetentionDays
				}
				if readsOn {
					var reads *webapp.ReadLedger
					var sessions webapp.SessionReadRepo
					if meta != nil {
						reads, err = webapp.NewReadLedger(meta.Reads(), retention)
						sessions = meta.SessionReads()
					} else {
						dir := filepath.Dir(projectsDB)
						reads, err = webapp.OpenReadLedger(filepath.Join(dir, "reads.json"), retention)
						sessions = webapp.OpenSessionReadRepo(filepath.Join(dir, "sessions.json"))
					}
					if err != nil {
						return fmt.Errorf("open read ledger: %w", err)
					}
					reads.WithSessions(sessions, sessRetention)
					defer reads.Close()
					srv.Reads = reads
				}
				if meta != nil {
					display += " (db: " + cfg.Database.Driver + ")"
				} else {
					display += " (auth: " + usersDB + ")"
				}
			}

			shown := addr
			if strings.HasPrefix(shown, ":") {
				shown = "localhost" + shown
			}
			fmt.Printf("serving %s\n  volume: %s\n  url:    http://%s\n", display, srv.Volume, shown)
			return http.ListenAndServe(addr, srv.Handler())
		},
	}
	c.Flags().StringVarP(&remoteURL, "remote", "r", "", "remote to serve (s3://bucket/prefix, gs://bucket/prefix, file:///path)")
	c.Flags().StringVar(&dir, "dir", "", "local folder to serve (default: current directory)")
	c.Flags().StringVar(&addr, "addr", ":4173", "address to listen on")
	c.Flags().StringVarP(&volume, "volume", "v", "", "volume display name (default: folder or remote basename)")
	c.Flags().DurationVar(&refresh, "refresh", 10*time.Second, "how long to cache the file listing")
	c.Flags().BoolVar(&upload, "upload", false, "allow clients to upload files")
	c.Flags().DurationVar(&uploadTTL, "upload-ttl", webapp.DefaultUploadTTL, "lifetime of presigned direct-upload URLs")
	c.Flags().StringVarP(&configPath, "config", "c", "", "JSON config file; explicit flags override its values")
	c.Flags().StringVar(&projectsDB, "projects-db", "", "hub project registry file (default: $BDRIVE_HOME/projects.json)")
	return c
}