package main

import (
	"fmt"
	"os"
	"slices"
)

func main() {
	if len(os.Args) == 1 || slices.Contains(os.Args, "-help") {
		printHelp()
		os.Exit(0)
	}

	var fromUser string
	var fromPassword string
	var toUser string
	var toPassword string
	var pdsUrl string
	var fromPdsUrl string
	var dryrun bool = false
	var verbose bool = false

	var importProfile bool = false
	var importFollows bool = false
	var importPreferences bool = false

	i := 1
	for {
		if i >= len(os.Args) { break }
		if os.Args[i][0] != '-' {
			fmt.Fprintf(os.Stderr, "unrecognised argument `%s`.\n", os.Args[i])
			os.Exit(1)
		}

		getValue := func(i int) (int, string) {
			if i + 1 >= len(os.Args) {
				fmt.Fprintf(os.Stderr, "-%s requires a value.\n", os.Args[i])
				os.Exit(1)
			}
			return i + 1, os.Args[i + 1]
		}

		switch os.Args[i][1:] {
		case "from":
			i, fromUser = getValue(i)
		case "frompass":
			i, fromPassword = getValue(i)
		case "to":
			i, toUser = getValue(i)
		case "topass":
			i, toPassword = getValue(i)
		case "pds":
			i, pdsUrl = getValue(i)
		case "frompds":
			i, fromPdsUrl = getValue(i)
		case "dryrun":
			dryrun = true
		case "v":
			verbose = true
		case "profile":
			importProfile = true
		case "follows":
			importFollows = true
		case "preferences":
			importPreferences = true
		}
		i += 1
	}

	if fromUser == "" {
		fmt.Fprintf(os.Stderr, "missing required argument -from.\n")
		os.Exit(1)
	}
	if toUser == "" {
		fmt.Fprintf(os.Stderr, "missing required argument -to.\n")
		os.Exit(1)
	}
	if toPassword == "" {
		fmt.Fprintf(os.Stderr, "missing required argument -pass.\n")
		os.Exit(1)
	}
	if pdsUrl == "" {
		fmt.Fprintf(os.Stderr, "missing required argument -pds.\n")
		os.Exit(1)
	}
	if fromPdsUrl == "" { fromPdsUrl = pdsUrl }

	if !(importProfile || importFollows || importPreferences) {
		fmt.Fprintf(os.Stderr, "no action was specified.\n")
		os.Exit(1)
	}

	var fromSession *AtprotoSession
	if !(fromPassword == "" || fromPdsUrl == "") {
		var err error
		fromSession, err = CreateSession(fromPdsUrl, fromUser, fromPassword)
		if err != nil {
			fmt.Fprintf(os.Stderr, "failed to create session for source account: %v\n", err)
			os.Exit(1)
		}
	}

	toSession, err := CreateSession(pdsUrl, toUser, toPassword)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to create session for destination account: %v\n", err)
		os.Exit(1)
	}

	if importProfile {
		err := ImportProfile(toSession, pdsUrl, fromUser, dryrun, verbose)
		if err != nil {
			fmt.Fprintf(os.Stderr, "failed to import profile: %v\n", err)
			os.Exit(1)
		}
	}
	if importPreferences {
		if fromSession == nil  {
			fmt.Fprintf(os.Stderr, "-frompass and -frompds must be provided for a preferences import.\n")
			os.Exit(1)
		}
		err := ImportPreferences(fromSession, toSession, pdsUrl, dryrun, verbose)
		if err != nil {
			fmt.Fprintf(os.Stderr, "failed to import preferences: %v\n", err)
			os.Exit(1)
		}
	}
	if importFollows {
		err := ImportFollows(toSession, pdsUrl, fromUser, dryrun, verbose)
		if err != nil {
			fmt.Fprintf(os.Stderr, "failed to import follows: %v\n", err)
			os.Exit(1)
		}
	}
}

func printHelp() {
	fmt.Printf(
`usage: %s <arguments...> <imports...>

required arguments:
	-from <identifier>: the source account handle or DID.
	-frompass <password>: the source account password.
	-to <identifier>: the destination account handle or DID.
	-topass <password>: the destination account password.
	-pds <pds-url>: the full https:// url of the destination account's PDS.

imports (at least one required):
	-profile: imports the account profile, including avatar, banner, display name, and description.
	-follows: imports the following list of the account.

optional arguments:
	-frompds <pds-url>: the source account's PDS url (defaults to the value of -pds).
	-dryrun: does not import follow records; good for sanity testing!
	-v: verbose output
	-help: shows this help message.
`,
	os.Args[0],
	)
}