package cli

import (
	"errors"
	"io"
	"os"
	"strings"
	"time"

	"sneak.berlin/go/vaultik/internal/globals"
	"sneak.berlin/go/vaultik/internal/ui"
)

// shortCommitLen is the number of git commit hash characters shown in
// the startup banner.
const shortCommitLen = 12

// exitCodeInterrupted is the exit status of a command that SIGINT or
// SIGTERM stopped. It is 128 plus SIGINT's number, 2, which is what a
// shell reports for a command stopped by Ctrl-C.
const exitCodeInterrupted = 130

// Entry is the main entry point for the CLI application.
// It prints the startup banner to stderr (unless a banner-suppressing
// flag is present in os.Args — see bannerSuppressedInArgs), executes the
// root cobra command, and routes any returned error through the
// ui.Writer so the user sees a properly formatted "🛑 ERROR:" line.
// The banner goes to stderr because stdout carries only the output the
// user asked for, such as a completion script or a `config get` value.
//
// It returns the process exit code (0 on success, 130 when interrupted,
// 1 on any other error) rather than calling os.Exit, so that main's
// deferred profile writers run before the process ends. See run in
// cmd/vaultik/main.go.
func Entry() int {
	emitStartupBanner(os.Args[1:], os.Stderr)

	rootCmd := NewRootCommand()
	rootCmd.SilenceErrors = true

	err := rootCmd.Execute()
	if err != nil {
		// An operation that ran inside the fx app has already reported
		// its own failure (`snapshot verify --json` puts it in the
		// document instead); errReported says so. Printing it again
		// here would double the error line.
		// Every other error — bad arguments, a config that would not
		// load, an interrupt — reaches Entry unreported, so it is shown
		// here.
		if !errors.Is(err, errReported) {
			ReportErrorf("%s", err.Error())
		}

		if errors.Is(err, errInterrupted) {
			return exitCodeInterrupted
		}

		return 1
	}

	return 0
}

// emitStartupBanner writes the startup banner to w unless args (the
// argument vector with the program name already stripped) contains a
// flag that suppresses it. Split out of Entry so that the decision is
// reachable from a test without running the whole CLI.
func emitStartupBanner(args []string, w io.Writer) {
	if bannerSuppressedInArgs(args) {
		return
	}

	short := globals.Commit
	if len(short) > shortCommitLen {
		short = short[:shortCommitLen]
	}

	writeStartupBanner(ui.New(w), time.Now().UTC(), short)
}

// ReportErrorf emits a user-facing error to stderr in the standard
// 🛑 ERROR: format. Use it from goroutine error paths (where returning
// an error to cobra isn't an option) and anywhere else a CLI command
// must surface a failure outside the normal RunE return path.
func ReportErrorf(format string, args ...any) {
	ui.New(os.Stderr).Errorf(format, args...)
}

// bannerSuppressedInArgs reports whether any of args is a flag that
// should suppress the startup banner (--quiet/-q/--cron/--json). Stops
// at the "--" argument terminator. Recognizes both long forms and short
// -q, including combined short flags like "-qv".
//
// This scans the raw argument vector because the banner is printed
// before cobra parses anything — deliberately, so that it still appears
// when cobra rejects the arguments and on --help. The consequence is
// that a flag is matched wherever it occurs in the vector, including
// positions where the command it belongs to would not accept it.
// --json is a subcommand flag rather than a persistent one, but so is
// --cron (it exists only on `snapshot create`), so this adds no new
// class of imprecision. The only cost of a false positive is a missing
// decorative banner.
func bannerSuppressedInArgs(args []string) bool {
	for _, a := range args {
		if a == "--" {
			return false
		}

		switch a {
		case "--quiet", "-q", "--cron", "--json":
			return true
		}

		if strings.HasPrefix(a, "--quiet=") ||
			strings.HasPrefix(a, "--cron=") ||
			strings.HasPrefix(a, "--json=") {
			return true
		}
		// Combined short flags like -qv or -vq.
		if len(a) > 1 && a[0] == '-' && a[1] != '-' {
			for _, c := range a[1:] {
				if c == 'q' {
					return true
				}
			}
		}
	}

	return false
}