package cli

import (
	"flag"
	"fmt"
	"io"
	"strconv"

	"git.dcglab.co.uk/steve/emcli/internal/store"
	"git.dcglab.co.uk/steve/emcli/internal/tui"
)

// runAccount handles `account add|list`. Human-readable output (never JSON).
func runAccount(args []string, out, errOut io.Writer) int {
	if len(args) == 0 {
		fmt.Fprintln(errOut, "usage: emcli account <add|list>")
		return 2
	}
	sub, rest := args[0], args[1:]
	st, err := openStore()
	if err != nil {
		fmt.Fprintf(errOut, "emcli: %v\n", err)
		return 1
	}
	defer st.Close()

	switch sub {
	case "add":
		if len(rest) == 0 { // no flags → interactive TUI form
			return addInteractive(st, tui.Fields{}, out, errOut)
		}
		fs := flag.NewFlagSet("account add", flag.ContinueOnError)
		fs.SetOutput(errOut)
		name := fs.String("name", "", "account name")
		mode := fs.String("mode", "RO", "RO|RW")
		host := fs.String("imap-host", "", "IMAP host")
		port := fs.Int("imap-port", 993, "IMAP port")
		sec := fs.String("imap-security", "tls", "tls|starttls")
		smtpHost := fs.String("smtp-host", "", "SMTP host (RW accounts)")
		smtpPort := fs.Int("smtp-port", 465, "SMTP port")
		smtpSec := fs.String("smtp-security", "tls", "tls|starttls")
		user := fs.String("username", "", "login username")
		pass := fs.String("password", "", "login password")
		subj := fs.String("subject-regex", "", "inbound subject filter")
		wlIn := fs.Bool("whitelist-in", false, "enable inbound whitelist")
		wlOut := fs.Bool("whitelist-out", false, "enable outbound whitelist")
		backlog := fs.Bool("process-backlog", false, "treat existing mail as new")
		if err := fs.Parse(rest); err != nil {
			return 2
		}
		if *name == "" || *host == "" || *user == "" {
			fmt.Fprintln(errOut, "name, imap-host, and username are required")
			return 2
		}
		acc := store.Account{
			Name: *name, Mode: *mode, IMAPHost: *host, IMAPPort: *port, IMAPSecurity: *sec,
			AuthType: "password", Username: *user, Password: *pass,
			SubjectRegex: *subj, WhitelistInEnabled: *wlIn, WhitelistOutEnabled: *wlOut,
			ProcessBacklog: *backlog,
		}
		if *mode == "RW" {
			acc.SMTPHost, acc.SMTPPort, acc.SMTPSecurity = *smtpHost, *smtpPort, *smtpSec
		}
		_, err := st.AddAccount(acc)
		if err != nil {
			fmt.Fprintf(errOut, "add account: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "account %q added (%s)\n", *name, *mode)
		return 0
	case "edit":
		fs := flag.NewFlagSet("account edit", flag.ContinueOnError)
		fs.SetOutput(errOut)
		name := fs.String("name", "", "account name (required)")
		mode := fs.String("mode", "", "RO|RW")
		host := fs.String("imap-host", "", "IMAP host")
		port := fs.Int("imap-port", 0, "IMAP port")
		sec := fs.String("imap-security", "", "tls|starttls")
		smtpHost := fs.String("smtp-host", "", "SMTP host")
		smtpPort := fs.Int("smtp-port", 0, "SMTP port")
		smtpSec := fs.String("smtp-security", "", "tls|starttls")
		user := fs.String("username", "", "login username")
		pass := fs.String("password", "", "login password (blank keeps existing)")
		subj := fs.String("subject-regex", "", "inbound subject filter")
		if err := fs.Parse(rest); err != nil {
			return 2
		}
		if *name == "" {
			fmt.Fprintln(errOut, "--name is required")
			return 2
		}
		if fs.NFlag() == 1 { // only --name → interactive TUI form, prefilled
			return editInteractive(st, *name, out, errOut)
		}
		acc, err := st.GetAccount(*name)
		if err != nil {
			fmt.Fprintf(errOut, "edit: %v\n", err)
			return 1
		}
		// Overlay only the flags the user actually set.
		fs.Visit(func(f *flag.Flag) {
			switch f.Name {
			case "mode":
				acc.Mode = *mode
			case "imap-host":
				acc.IMAPHost = *host
			case "imap-port":
				acc.IMAPPort = *port
			case "imap-security":
				acc.IMAPSecurity = *sec
			case "smtp-host":
				acc.SMTPHost = *smtpHost
			case "smtp-port":
				acc.SMTPPort = *smtpPort
			case "smtp-security":
				acc.SMTPSecurity = *smtpSec
			case "username":
				acc.Username = *user
			case "password":
				acc.Password = *pass
			case "subject-regex":
				acc.SubjectRegex = *subj
			}
		})
		// acc.Password holds the existing (decrypted) password from GetAccount; the
		// Visit above overwrites it only when --password was passed. UpdateAccount
		// re-seals whatever non-empty value is present, so the password is preserved.
		if err := st.UpdateAccount(acc); err != nil {
			fmt.Fprintf(errOut, "edit: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "account %q updated\n", *name)
		return 0
	case "remove":
		fs := flag.NewFlagSet("account remove", flag.ContinueOnError)
		fs.SetOutput(errOut)
		name := fs.String("name", "", "account name (required)")
		yes := fs.Bool("yes", false, "skip confirmation")
		if err := fs.Parse(rest); err != nil {
			return 2
		}
		if *name == "" {
			fmt.Fprintln(errOut, "--name is required")
			return 2
		}
		if !*yes {
			fmt.Fprintf(errOut, "refusing to remove %q without --yes\n", *name)
			return 2
		}
		if err := st.DeleteAccount(*name); err != nil {
			fmt.Fprintf(errOut, "remove: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "account %q removed\n", *name)
		return 0
	case "list":
		accs, err := st.ListAccounts()
		if err != nil {
			fmt.Fprintf(errOut, "list: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "%-16s %-4s %-28s %s\n", "NAME", "MODE", "IMAP", "USER")
		for _, a := range accs {
			fmt.Fprintf(out, "%-16s %-4s %-28s %s\n",
				a.Name, a.Mode, fmt.Sprintf("%s:%d", a.IMAPHost, a.IMAPPort), a.Username)
		}
		return 0
	default:
		fmt.Fprintf(errOut, "unknown account subcommand %q\n", sub)
		return 2
	}
}

// auditList renders recent audit entries (account "" = all) to out.
func auditList(st *store.Store, account string, limit int, out io.Writer) error {
	entries, err := st.RecentAuditFor(account, limit)
	if err != nil {
		return err
	}
	fmt.Fprintf(out, "%-20s %-12s %-8s %-8s %-20s %s\n",
		"TS", "ACCOUNT", "ACTION", "RESULT", "TARGET", "REASON")
	for _, e := range entries {
		fmt.Fprintf(out, "%-20s %-12s %-8s %-8s %-20s %s\n",
			e.TS, e.Account, e.Action, e.Result, e.Target, e.Reason)
	}
	return nil
}

// runConfig handles `config set <key> <value>` and `config get <key>`.
func runConfig(args []string, out, errOut io.Writer) int {
	if len(args) < 2 {
		fmt.Fprintln(errOut, "usage: emcli config <set|get> <key> [value]")
		return 2
	}
	sub, key := args[0], args[1]
	st, err := openStore()
	if err != nil {
		fmt.Fprintf(errOut, "emcli: %v\n", err)
		return 1
	}
	defer st.Close()

	switch sub {
	case "set":
		if len(args) < 3 {
			fmt.Fprintln(errOut, "usage: emcli config set <key> <value>")
			return 2
		}
		value := args[2]
		if key == "audit_retention_days" {
			n, err := strconv.Atoi(value)
			if err != nil || n < 0 {
				fmt.Fprintf(errOut, "audit_retention_days must be an integer >= 0, got %q\n", value)
				return 2
			}
		}
		if err := st.SetSetting(key, value); err != nil {
			fmt.Fprintf(errOut, "config set: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "%s = %s\n", key, value)
		return 0
	case "get":
		v, err := st.GetSetting(key)
		if err != nil {
			fmt.Fprintf(errOut, "config get: %s not set\n", key)
			return 1
		}
		fmt.Fprintf(out, "%s = %s\n", key, v)
		return 0
	default:
		fmt.Fprintf(errOut, "unknown config subcommand %q\n", sub)
		return 2
	}
}

// runAudit handles `audit list [--account <name>] [--limit N]`.
func runAudit(args []string, out, errOut io.Writer) int {
	if len(args) == 0 || args[0] != "list" {
		fmt.Fprintln(errOut, "usage: emcli audit list [--account <name>] [--limit N]")
		return 2
	}
	fs := flag.NewFlagSet("audit list", flag.ContinueOnError)
	fs.SetOutput(errOut)
	account := fs.String("account", "", "filter by account")
	limit := fs.Int("limit", 50, "max rows")
	if err := fs.Parse(args[1:]); err != nil {
		return 2
	}
	st, err := openStore()
	if err != nil {
		fmt.Fprintf(errOut, "emcli: %v\n", err)
		return 1
	}
	defer st.Close()
	if err := auditList(st, *account, *limit, out); err != nil {
		fmt.Fprintf(errOut, "audit list: %v\n", err)
		return 1
	}
	return 0
}

// runWhitelist handles `whitelist <in|out> add --account NAME --address A`.
func runWhitelist(args []string, out, errOut io.Writer) int {
	if len(args) < 2 {
		fmt.Fprintln(errOut, "usage: emcli whitelist <in|out> <add|remove|list> [flags]")
		return 2
	}
	dir := store.Direction(args[0])
	sub, rest := args[1], args[2:]
	fs := flag.NewFlagSet("whitelist", flag.ContinueOnError)
	fs.SetOutput(errOut)
	account := fs.String("account", "", "account name")
	address := fs.String("address", "", "email or @domain")
	if err := fs.Parse(rest); err != nil {
		return 2
	}
	if *account == "" {
		fmt.Fprintln(errOut, "--account is required")
		return 2
	}
	st, err := openStore()
	if err != nil {
		fmt.Fprintf(errOut, "emcli: %v\n", err)
		return 1
	}
	defer st.Close()

	switch sub {
	case "add":
		if err := st.AddWhitelist(*account, dir, *address); err != nil {
			fmt.Fprintf(errOut, "add: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "added %s to %s whitelist of %q\n", *address, dir, *account)
	case "remove":
		if err := st.RemoveWhitelist(*account, dir, *address); err != nil {
			fmt.Fprintf(errOut, "remove: %v\n", err)
			return 1
		}
		fmt.Fprintf(out, "removed %s\n", *address)
	case "list":
		addrs, err := st.ListWhitelist(*account, dir)
		if err != nil {
			fmt.Fprintf(errOut, "list: %v\n", err)
			return 1
		}
		for _, a := range addrs {
			fmt.Fprintln(out, a)
		}
	default:
		fmt.Fprintf(errOut, "unknown whitelist subcommand %q\n", sub)
		return 2
	}
	return 0
}