package cli

import (
	"flag"
	"fmt"
	"io"
	"strconv"
	"strings"
	"time"

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

func realMailer(acc store.Account) (Mailer, error) {
	c, err := mail.Dial(mail.IMAPConfig{
		Host: acc.IMAPHost, Port: acc.IMAPPort, Security: acc.IMAPSecurity,
		Username: acc.Username, Password: acc.Password,
	})
	if err != nil {
		return nil, err
	}
	return c, nil
}

// openStore loads the key and opens the DB, returning a human-readable error string.
func openStore() (*store.Store, error) {
	key, err := crypto.KeyFromEnv()
	if err != nil {
		return nil, err
	}
	path, err := store.DefaultDBPath()
	if err != nil {
		return nil, err
	}
	return store.Open(path, key)
}

func newDepsLive(st *store.Store, out io.Writer) Deps {
	return Deps{Store: st, Dial: realMailer, Now: time.Now, Out: out}
}

// Run routes a command line and returns an exit code.
func Run(args []string, out, errOut io.Writer) int {
	if len(args) == 0 {
		fmt.Fprintln(errOut, "emcli: no command given")
		return 2
	}
	cmd, rest := args[0], args[1:]
	switch cmd {
	case "list", "get", "search", "ack":
		return runAgent(cmd, rest, out, errOut)
	case "account":
		return runAccount(rest, out, errOut)
	case "whitelist":
		return runWhitelist(rest, out, errOut)
	default:
		fmt.Fprintf(errOut, "emcli: unknown command %q\n", cmd)
		return 2
	}
}

// runAgent handles JSON-emitting commands. Errors are emitted as JSON envelopes.
func runAgent(cmd string, args []string, out, errOut io.Writer) int {
	fs := flag.NewFlagSet(cmd, flag.ContinueOnError)
	fs.SetOutput(errOut)
	account := fs.String("account", "", "account name")
	folder := fs.String("folder", "INBOX", "folder/mailbox")
	onlyNew := fs.Bool("new", false, "only new (unacked) messages")
	limit := fs.Int("limit", 50, "max results (cap 500)")
	uid := fs.Uint("uid", 0, "message UID (get)")
	before := fs.Uint("before", 0, "list: UID cursor, older than")
	since := fs.Uint("since", 0, "list: UID cursor, newer than")
	from := fs.String("from", "", "search: sender")
	subjectContains := fs.String("subject-contains", "", "search: subject substring")
	text := fs.String("text", "", "search: full-text")
	sinceDate := fs.String("since-date", "", "search: RFC3339 date lower bound")
	beforeDate := fs.String("before-date", "", "search: RFC3339 date upper bound")
	ackUIDs := fs.String("uid-list", "", "ack: comma-separated UIDs")
	if err := fs.Parse(args); err != nil {
		_ = Failure(CodeUsage, err.Error()).Write(out)
		return 2
	}
	if *limit > 500 {
		*limit = 500
	}
	if *account == "" {
		_ = Failure(CodeUsage, "--account is required").Write(out)
		return 2
	}
	st, err := openStore()
	if err != nil {
		_ = Failure(CodeConfig, err.Error()).Write(out)
		return 1
	}
	defer st.Close()
	_, _ = st.PurgeAudit(time.Now())
	d := newDepsLive(st, out)

	switch cmd {
	case "list":
		if err := ListCmd(d, *account, *folder, *onlyNew, u32(*before), u32(*since), *limit); err != nil {
			return 1
		}
	case "get":
		if *uid == 0 {
			_ = Failure(CodeUsage, "--uid is required").Write(out)
			return 2
		}
		if err := GetCmd(d, *account, *folder, u32(*uid)); err != nil {
			return 1
		}
	case "search":
		sc := mail.SearchCriteria{From: *from, SubjectContains: *subjectContains, Text: *text}
		if *sinceDate != "" {
			if tm, err := time.Parse(time.RFC3339, *sinceDate); err == nil {
				sc.Since = tm
			}
		}
		if *beforeDate != "" {
			if tm, err := time.Parse(time.RFC3339, *beforeDate); err == nil {
				sc.Before = tm
			}
		}
		if err := SearchCmd(d, *account, *folder, sc, *limit); err != nil {
			return 1
		}
	case "ack":
		uids, err := parseUIDList(*ackUIDs)
		if err != nil {
			_ = Failure(CodeUsage, err.Error()).Write(out)
			return 2
		}
		if err := AckCmd(d, *account, *folder, uids); err != nil {
			return 1
		}
	}
	return 0
}

func u32(u uint) uint32 { return uint32(u) }

func parseUIDList(s string) ([]uint32, error) {
	if strings.TrimSpace(s) == "" {
		return nil, fmt.Errorf("--uid-list is required")
	}
	var out []uint32
	for _, part := range strings.Split(s, ",") {
		n, err := strconv.ParseUint(strings.TrimSpace(part), 10, 32)
		if err != nil {
			return nil, fmt.Errorf("invalid uid %q", part)
		}
		out = append(out, uint32(n))
	}
	return out, nil
}