package main

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"sort"
	"strconv"
	"strings"

	"github.com/spf13/cobra"
	"golang.org/x/term"

	"housecarl/internal/api"
	"housecarl/internal/model"
)

func historyCmd() *cobra.Command {
	cmd := &cobra.Command{Use: "history", Short: "The history of configuration changes, and undo"}
	var limit int
	list := &cobra.Command{
		Use: "list", Short: "List recent changes", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			var hs []model.HistoryEntry
			if err := c.Get(ctx(), "/history", q("limit", strconv.Itoa(limit)), &hs); err != nil {
				return err
			}
			return output(hs, func(w io.Writer) {
				fmt.Fprintln(w, "ID\tWHEN\tBY\tVIA\tCHANGES\tDESCRIPTION")
				for _, h := range hs {
					desc := h.Description
					if h.RevertedBy != 0 {
						desc += fmt.Sprintf(" (undone by %d)", h.RevertedBy)
					}
					fmt.Fprintf(w, "%d\t%s\t%s\t%s\t%d\t%s\n", h.ID, h.Time.Local().Format("2006-01-02 15:04"), h.Username, h.Via, len(h.Changes), desc)
				}
			})
		},
	}
	list.Flags().IntVar(&limit, "limit", 30, "how many")
	cmd.AddCommand(list)
	cmd.AddCommand(&cobra.Command{
		Use: "show ID", Short: "Show a change: each object before and after", Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			var h model.HistoryEntry
			if err := c.Get(ctx(), "/history/"+args[0], nil, &h); err != nil {
				return err
			}
			return output(h, func(w io.Writer) {
				fmt.Fprintf(w, "%d\t%s by %s (%s): %s\n", h.ID, h.Time.Local().Format("2006-01-02 15:04:05"), h.Username, h.Via, h.Description)
				for _, ch := range h.Changes {
					fmt.Fprintf(w, "\n%s %s %s\n", ch.Action(), ch.Kind, ch.Label)
					for _, line := range diffJSON(ch.Before, ch.After) {
						fmt.Fprintln(w, "  "+line)
					}
				}
			})
		},
	})
	cmd.AddCommand(&cobra.Command{
		Use:   "undo ID",
		Short: "Undo a change",
		Long: `Undoes a change by applying it backwards. It is refused when an object the
change touched has changed since; undo the later changes first.`,
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			var resp api.MutationResponse
			if err := c.Do(ctx(), "POST", "/history/"+args[0]+"/revert", nil, nil, &resp); err != nil {
				return err
			}
			return report(&resp)
		},
	})
	return cmd
}

// diffJSON lists the fields that differ between two versions of an
// object: "name: office -> lab".
func diffJSON(before, after json.RawMessage) []string {
	var a, b map[string]any
	json.Unmarshal(before, &a)
	json.Unmarshal(after, &b)
	keys := map[string]bool{}
	for k := range a {
		keys[k] = true
	}
	for k := range b {
		keys[k] = true
	}
	var names []string
	for k := range keys {
		names = append(names, k)
	}
	sort.Strings(names)
	var out []string
	show := func(v any, ok bool) string {
		if !ok {
			return "-"
		}
		x, _ := json.Marshal(v)
		return string(x)
	}
	for _, k := range names {
		va, oka := a[k]
		vb, okb := b[k]
		sa, sb := show(va, oka), show(vb, okb)
		if sa == sb {
			continue
		}
		switch {
		case before == nil:
			out = append(out, k+": "+sb)
		case after == nil:
			out = append(out, k+": "+sa)
		default:
			out = append(out, k+": "+sa+" -> "+sb)
		}
	}
	return out
}

func whoamiCmd() *cobra.Command {
	return &cobra.Command{
		Use: "whoami", Short: "Show who you are to the server", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			var me api.Whoami
			if err := c.Get(ctx(), "/auth/whoami", nil, &me); err != nil {
				return err
			}
			return output(me, func(w io.Writer) {
				fmt.Fprintf(w, "User:\t%s (%s)\n", me.User.Username, me.Method)
				fmt.Fprintf(w, "Administrator:\t%v\n", me.Admin)
				fmt.Fprintf(w, "May:\t%s\n", strings.Join(me.Permissions, ", "))
				fmt.Fprintf(w, "Server:\tHousecarl %s\n", me.Build.String())
			})
		},
	}
}

func readSecret(prompt string) (string, error) {
	fmt.Fprint(os.Stderr, prompt)
	if term.IsTerminal(int(os.Stdin.Fd())) {
		b, err := term.ReadPassword(int(os.Stdin.Fd()))
		fmt.Fprintln(os.Stderr)
		return strings.TrimSpace(string(b)), err
	}
	var s string
	_, err := fmt.Fscanln(os.Stdin, &s)
	return strings.TrimSpace(s), err
}

func userID(name string) (int64, error) {
	c, err := newClient()
	if err != nil {
		return 0, err
	}
	var us []api.User
	if err := c.Get(ctx(), "/users", nil, &us); err != nil {
		return 0, err
	}
	for _, u := range us {
		if strings.EqualFold(u.Username, name) || strconv.FormatInt(u.ID, 10) == name {
			return u.ID, nil
		}
	}
	return 0, fmt.Errorf("no user %s", name)
}

func userCmd() *cobra.Command {
	cmd := &cobra.Command{Use: "user", Aliases: []string{"users"}, Short: "Users (administrators only)"}
	cmd.AddCommand(&cobra.Command{
		Use: "list", Short: "List users", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			var us []api.User
			if err := c.Get(ctx(), "/users", nil, &us); err != nil {
				return err
			}
			return output(us, func(w io.Writer) {
				fmt.Fprintln(w, "ID\tUSER\tADMIN\tGRANTS\tPASSWORD\tDISABLED\tLAST LOGIN")
				for _, u := range us {
					login := "-"
					if u.LastLoginAt != nil {
						login = fmtWhen(*u.LastLoginAt)
					}
					fmt.Fprintf(w, "%d\t%s\t%v\t%s\t%v\t%v\t%s\n", u.ID, u.Username, u.Admin, orDash(strings.Join(u.GrantStrings, " ")), u.HasPassword, u.Disabled, login)
				}
			})
		},
	})
	var admin, noPassword bool
	var role, comment string
	var grants []string
	add := &cobra.Command{
		Use:   "add USER",
		Short: "Add a user (asks for the password)",
		Long: `Adds a user. Without --admin, give what they may do: a role (viewer,
operator, log) or grants such as --grant config:read --grant sets:write:guests.
--no-password makes a service account that only uses API tokens.`,
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			in := api.UserInput{Username: &args[0], Admin: &admin}
			if !noPassword {
				pw, err := readSecret("Password for " + args[0] + ": ")
				if err != nil {
					return err
				}
				in.Password = &pw
			}
			if role != "" {
				in.Role = &role
			}
			if grants != nil {
				in.Grants = &grants
			}
			if comment != "" {
				in.Comment = &comment
			}
			var u api.User
			if err := c.Do(ctx(), "POST", "/users", nil, in, &u); err != nil {
				return err
			}
			if !flagQuiet {
				fmt.Printf("added user %s (%d)\n", u.Username, u.ID)
			}
			return nil
		},
	}
	f := add.Flags()
	f.BoolVar(&admin, "admin", false, "an administrator (may do everything)")
	f.StringVar(&role, "role", "", "a role: viewer, operator or log")
	f.StringArrayVar(&grants, "grant", nil, "a grant, resource:access (config, sets, log, audit; read or write; sets:write:SET,SET)")
	f.BoolVar(&noPassword, "no-password", false, "no password: API tokens only")
	f.StringVar(&comment, "comment", "", "a comment")
	cmd.AddCommand(add)

	var setPassword, disable, enable bool
	update := &cobra.Command{
		Use: "update USER", Short: "Change a user", Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			id, err := userID(args[0])
			if err != nil {
				return err
			}
			c, _ := newClient()
			in := api.UserInput{}
			fl := cmd.Flags()
			if fl.Changed("admin") {
				in.Admin = &admin
			}
			if fl.Changed("role") {
				in.Role = &role
			}
			if fl.Changed("grant") {
				in.Grants = &grants
			}
			if fl.Changed("comment") {
				in.Comment = &comment
			}
			if disable || enable {
				in.Disabled = &disable
			}
			if setPassword {
				pw, err := readSecret("New password for " + args[0] + ": ")
				if err != nil {
					return err
				}
				in.Password = &pw
			}
			var u api.User
			if err := c.Do(ctx(), "PATCH", "/users/"+strconv.FormatInt(id, 10), nil, in, &u); err != nil {
				return err
			}
			if !flagQuiet {
				fmt.Printf("updated user %s\n", u.Username)
			}
			return nil
		},
	}
	f = update.Flags()
	f.BoolVar(&admin, "admin", false, "make (or with --admin=false, unmake) an administrator")
	f.StringVar(&role, "role", "", "replace the grants with a role's")
	f.StringArrayVar(&grants, "grant", nil, "replace the grants (repeat for several)")
	f.BoolVar(&setPassword, "password", false, "set a new password (asks for it)")
	f.BoolVar(&disable, "disable", false, "disable the user (logs them out)")
	f.BoolVar(&enable, "enable", false, "enable the user again")
	f.StringVar(&comment, "comment", "", "a comment")
	cmd.AddCommand(update)
	cmd.AddCommand(&cobra.Command{
		Use: "delete USER", Short: "Delete a user and their tokens", Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			id, err := userID(args[0])
			if err != nil {
				return err
			}
			c, _ := newClient()
			if err := c.Do(ctx(), "DELETE", "/users/"+strconv.FormatInt(id, 10), nil, nil, nil); err != nil {
				return err
			}
			if !flagQuiet {
				fmt.Println("deleted user", args[0])
			}
			return nil
		},
	})
	return cmd
}

func tokenCmd() *cobra.Command {
	cmd := &cobra.Command{Use: "token", Aliases: []string{"tokens"}, Short: "API tokens"}
	var all bool
	var user string
	list := &cobra.Command{
		Use: "list", Short: "List your tokens (--all: everyone's, for administrators)", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			path := "/me/tokens"
			if all {
				path = "/tokens"
			}
			var ts []api.Token
			if err := c.Get(ctx(), path, nil, &ts); err != nil {
				return err
			}
			return output(ts, func(w io.Writer) {
				fmt.Fprintln(w, "ID\tUSER\tNAME\tGRANTS\tEXPIRES\tLAST USED")
				for _, t := range ts {
					exp, used := "never", "never"
					if t.ExpiresAt != nil {
						exp = fmtWhen(*t.ExpiresAt)
					}
					if t.LastUsedAt != nil {
						used = fmtWhen(*t.LastUsedAt) + " from " + t.LastUsedIP
					}
					fmt.Fprintf(w, "%d\t%s\t%s\t%s\t%s\t%s\n", t.ID, t.Username, t.Name, strings.Join(t.GrantStrings, " "), exp, used)
				}
			})
		},
	}
	list.Flags().BoolVar(&all, "all", false, "everyone's tokens")
	cmd.AddCommand(list)
	var role, expires string
	var grants []string
	var save bool
	create := &cobra.Command{
		Use:   "create NAME",
		Short: "Make an API token (the secret is shown once)",
		Long: `Makes an API token. It has all of its user's permissions unless --role or
--grant narrows it. On the server as root, --user names whose token it is.
--save puts it in the CLI's configuration.`,
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			path := "/me/tokens"
			if user != "" {
				id, err := userID(user)
				if err != nil {
					return err
				}
				path = "/users/" + strconv.FormatInt(id, 10) + "/tokens"
			}
			in := api.TokenInput{Name: args[0], Role: role, Grants: grants, ExpiresIn: expires}
			var t api.Token
			if err := c.Do(ctx(), "POST", path, nil, in, &t); err != nil {
				return err
			}
			if save {
				cfg, err := loadCLIConfig()
				if err != nil {
					return err
				}
				cfg.Token = t.Secret
				if err := saveCLIConfig(cfg); err != nil {
					return err
				}
				fmt.Fprintln(os.Stderr, "saved in", flagConfig)
			}
			if flagOutput == "json" || flagOutput == "yaml" {
				return output(t, nil)
			}
			fmt.Println(t.Secret)
			if !flagQuiet {
				fmt.Fprintln(os.Stderr, "this is the only time the token is shown; keep it safe")
			}
			return nil
		},
	}
	f := create.Flags()
	f.StringVar(&role, "role", "", "narrow it to a role: viewer, operator or log")
	f.StringArrayVar(&grants, "grant", nil, "narrow it to grants (resource:access)")
	f.StringVar(&expires, "expires", "", "expire after this long (90d, 720h)")
	f.StringVar(&user, "user", "", "the user it belongs to (administrators)")
	f.BoolVar(&save, "save", false, "save it as this CLI's token")
	cmd.AddCommand(create)
	var grace, rexp string
	var current, rsave bool
	rotate := &cobra.Command{
		Use:   "rotate [ID]",
		Short: "Give a token a new secret (shown once)",
		Long: `Gives a token a new secret. It keeps its ID, name and permissions, so only
the programs that use it need the new secret. The old secret stops at once,
or after --grace (up to 7d) so you can update them without an outage. A
token that expires gets its lifetime again, from now, unless --expires says
otherwise (90d, or never).

  hc token rotate --current --save            # this CLI's own token`,
		Args: cobra.MaximumNArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			id := ""
			switch {
			case current && len(args) == 0:
				var me api.Whoami
				if err := c.Get(ctx(), "/auth/whoami", nil, &me); err != nil {
					return err
				}
				if me.TokenID == 0 {
					return fmt.Errorf("this CLI isn't using a token (%s); give the token's ID", me.Method)
				}
				id = strconv.FormatInt(me.TokenID, 10)
			case len(args) == 1 && !current:
				id = args[0]
			default:
				return fmt.Errorf("give the token's ID, or --current")
			}
			body := api.TokenRotation{Grace: grace}
			switch rexp {
			case "":
			case "never":
				body.NoExpiry = true
			default:
				body.ExpiresIn = rexp
			}
			var t api.Token
			if err := c.Do(ctx(), "POST", "/tokens/"+id+"/rotate", nil, body, &t); err != nil {
				return err
			}
			if rsave {
				cfg, err := loadCLIConfig()
				if err != nil {
					return err
				}
				cfg.Token = t.Secret
				if err := saveCLIConfig(cfg); err != nil {
					return err
				}
				fmt.Fprintln(os.Stderr, "saved in", flagConfig)
			}
			if flagOutput == "json" || flagOutput == "yaml" {
				return output(t, nil)
			}
			fmt.Println(t.Secret)
			if !flagQuiet {
				if t.PrevExpiresAt != nil {
					fmt.Fprintf(os.Stderr, "the old secret works until %s\n", t.PrevExpiresAt.Local().Format("2006-01-02 15:04"))
				} else {
					fmt.Fprintln(os.Stderr, "the old secret no longer works")
				}
			}
			return nil
		},
	}
	f = rotate.Flags()
	f.StringVar(&grace, "grace", "", "keep the old secret working this long (30m, 24h, up to 7d)")
	f.StringVar(&rexp, "expires", "", "a new lifetime from now (90d), or never")
	f.BoolVar(&current, "current", false, "rotate the token this CLI uses")
	f.BoolVar(&rsave, "save", false, "save the new secret as this CLI's token")
	cmd.AddCommand(rotate)
	cmd.AddCommand(&cobra.Command{
		Use: "revoke ID", Short: "Revoke a token", Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			if err := c.Do(ctx(), "DELETE", "/tokens/"+args[0], nil, nil, nil); err != nil {
				return err
			}
			if !flagQuiet {
				fmt.Println("revoked token", args[0])
			}
			return nil
		},
	})
	return cmd
}

func passwordCmd() *cobra.Command {
	return &cobra.Command{
		Use: "password", Short: "Change your own password", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			cur, err := readSecret("Current password: ")
			if err != nil {
				return err
			}
			pw, err := readSecret("New password: ")
			if err != nil {
				return err
			}
			if err := c.Do(ctx(), "POST", "/me/password", nil, api.PasswordChange{Current: cur, Password: pw}, nil); err != nil {
				return err
			}
			fmt.Println("password changed")
			return nil
		},
	}
}

func auditCmd() *cobra.Command {
	var user, action, search string
	var limit int
	cmd := &cobra.Command{
		Use: "audit", Short: "Show the audit log: logins, users, tokens, changes, confirmations, set entries", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			c, err := newClient()
			if err != nil {
				return err
			}
			var evs []model.AuditEvent
			if err := c.Get(ctx(), "/audit", q("user", user, "action", action, "q", search, "limit", strconv.Itoa(limit)), &evs); err != nil {
				return err
			}
			return output(evs, func(w io.Writer) {
				fmt.Fprintln(w, "WHEN\tUSER\tFROM\tACTION\tOBJECT\tRESULT\tDETAIL")
				for _, e := range evs {
					fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\t%s\t%s\n", e.Time.Local().Format("2006-01-02 15:04:05"), orDash(e.Username), orDash(e.IP), e.Action, orDash(e.Object), e.Result, e.Detail)
				}
			})
		},
	}
	f := cmd.Flags()
	f.StringVar(&user, "user", "", "only this user's")
	f.StringVar(&action, "action", "", "only actions starting with this (auth., config., set.)")
	f.StringVar(&search, "search", "", "only events whose object or detail contains this")
	f.IntVar(&limit, "limit", 100, "how many")
	return cmd
}

func configCmd() *cobra.Command {
	cmd := &cobra.Command{Use: "config", Short: "This CLI's settings: the server and token"}
	cmd.AddCommand(&cobra.Command{
		Use: "show", Short: "Show the CLI's configuration", Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := loadCLIConfig()
			if err != nil {
				return err
			}
			tok := "-"
			if cfg.Token != "" {
				tok = cfg.Token[:min(len(cfg.Token), 24)] + "…"
			}
			fmt.Printf("file:     %s\nserver:   %s\ntoken:    %s\ninsecure: %v\nca_cert:  %s\n", flagConfig, orDash(cfg.Server)+" (empty: the local socket)", tok, cfg.Insecure, orDash(cfg.CACert))
			return nil
		},
	})
	cmd.AddCommand(&cobra.Command{
		Use:   "set KEY [VALUE]",
		Short: "Set server, token (asks when no value), insecure or ca_cert",
		Args:  cobra.RangeArgs(1, 2),
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := loadCLIConfig()
			if err != nil {
				return err
			}
			val := ""
			if len(args) == 2 {
				val = args[1]
			} else if args[0] == "token" {
				if val, err = readSecret("API token: "); err != nil {
					return err
				}
			}
			switch args[0] {
			case "server":
				cfg.Server = val
			case "token":
				cfg.Token = val
			case "insecure":
				cfg.Insecure = val == "true" || val == "yes" || val == "on"
			case "ca_cert", "ca-cert":
				cfg.CACert = val
			default:
				return fmt.Errorf("unknown setting %q (use server, token, insecure or ca_cert)", args[0])
			}
			if err := saveCLIConfig(cfg); err != nil {
				return err
			}
			fmt.Fprintln(os.Stderr, "saved in", flagConfig)
			return nil
		},
	})
	return cmd
}