package bonfire

import (
	"strconv"

	"git.golem15.com/golem15/summercms/internal/consolekit"
	"strings"

	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
)

// maxVerbosity caps -v, -vv and -vvv (and repeated --verbose).
const maxVerbosity = consolekit.MaxVerbosity

// Globals are the global console options every command accepts: -v, -vv and
// -vvv (--verbose), -q (--quiet), --ansi and --no-ansi, -n
// (--no-interaction) and --env. The fields are Verbosity (0, or 1 to 3 for
// -v to -vvv), Quiet (implies NoInteraction), Color (ColorAlways for
// --ansi, ColorNever for --no-ansi, ColorAuto otherwise; the last of the
// two flags wins), NoInteraction and Env. Its Args method re-serialises
// them as flags for forwarding to another program.
type Globals = consolekit.Globals

// Global option names and shorthands, reserved on every command.
const (
	flagVerbose       = "verbose"
	flagQuiet         = "quiet"
	flagANSI          = "ansi"
	flagNoANSI        = "no-ansi"
	flagNoInteraction = "no-interaction"
	flagEnv           = "env"
	flagHelp          = "help"
)

var (
	reservedFlagNames      = []string{flagVerbose, flagQuiet, flagANSI, flagNoANSI, flagNoInteraction, flagEnv, flagHelp}
	reservedFlagShorthands = []string{"v", "q", "n", "h"}
)

// PeekGlobals reads the global options from args before the command root
// exists, so the generated main can pick the configuration environment and
// the log verbosity before config loads and plugins boot. The scan is
// tolerant: it never fails, ignores every other token and stops at "--".
// It reads the =value forms the way pflag does (--verbose=2, -v=3,
// --quiet=false, -n=1, --ansi=false), ignoring a value pflag would reject.
// Quiet also sets NoInteraction. A value-taking command flag followed by a
// global-looking token (--name -v) is read as the global before boot; the
// command and its error block use cobra's reading.
func PeekGlobals(args []string) Globals {
	var g Globals
	for i := 0; i < len(args); i++ {
		a := args[i]
		if name, value, ok := strings.Cut(a, "="); ok && strings.HasPrefix(name, "--") {
			switch strings.TrimPrefix(name, "--") {
			case flagVerbose:
				peekCount(&g.Verbosity, value)
			case flagQuiet:
				peekBool(&g.Quiet, value)
			case flagNoInteraction:
				peekBool(&g.NoInteraction, value)
			case flagANSI:
				peekColor(&g.Color, ColorAlways, value)
			case flagNoANSI:
				peekColor(&g.Color, ColorNever, value)
			case flagEnv:
				g.Env = value
			}
			continue
		}
		switch {
		case a == "--":
			return normalize(g)
		case a == "--"+flagVerbose:
			g.Verbosity++
		case a == "-q" || a == "--"+flagQuiet:
			g.Quiet = true
		case a == "-n" || a == "--"+flagNoInteraction:
			g.NoInteraction = true
		case a == "--"+flagANSI:
			g.Color = ColorAlways
		case a == "--"+flagNoANSI:
			g.Color = ColorNever
		case a == "--"+flagEnv:
			if i+1 < len(args) {
				g.Env = args[i+1]
				i++
			}
		case isShorthandCluster(a):
			peekShorthands(&g, a[1:])
		}
	}
	return normalize(g)
}

// peekCount applies a --verbose=N or -v=N value the way pflag's count flag
// does: the value replaces the count; an unparsable value is ignored.
func peekCount(n *int, value string) {
	if v, err := strconv.ParseInt(value, 0, 0); err == nil {
		*n = int(v)
	}
}

// peekBool applies a bool flag's =value the way pflag does; an unparsable
// value is ignored.
func peekBool(b *bool, value string) {
	if v, err := strconv.ParseBool(value); err == nil {
		*b = v
	}
}

// peekColor applies --ansi=B or --no-ansi=B the way colorFlag.Set does:
// true sets the flag's mode, false resets the mode to ColorAuto only when it
// is the flag's own; an unparsable value is ignored.
func peekColor(mode *ColorMode, set ColorMode, value string) {
	on, err := strconv.ParseBool(value)
	switch {
	case err != nil:
	case on:
		*mode = set
	case *mode == set:
		*mode = ColorAuto
	}
}

// isShorthandCluster reports a single-dash token such as -v, -vvv or -qn.
func isShorthandCluster(a string) bool {
	return len(a) >= 2 && a[0] == '-' && a[1] != '-'
}

// peekShorthands reads a cluster of shorthands the way pflag does (-qn is
// -q -n, -vvq is -v -v -q, -v=3 sets the count, -qn=false turns -n off). It
// stops at the first letter that is not a global shorthand: that may be a
// command flag whose value is the rest of the token.
func peekShorthands(g *Globals, cluster string) {
	for i := 0; i < len(cluster); i++ {
		r := cluster[i]
		if i+1 < len(cluster) && cluster[i+1] == '=' {
			value := cluster[i+2:]
			switch r {
			case 'v':
				peekCount(&g.Verbosity, value)
			case 'q':
				peekBool(&g.Quiet, value)
			case 'n':
				peekBool(&g.NoInteraction, value)
			}
			return
		}
		switch r {
		case 'v':
			g.Verbosity++
		case 'q':
			g.Quiet = true
		case 'n':
			g.NoInteraction = true
		case 'h':
		default:
			return
		}
	}
}

// normalize caps the verbosity and lets Quiet imply NoInteraction.
func normalize(g Globals) Globals {
	return consolekit.Normalize(g)
}

// globalFlags holds the parsed persistent flags of one root.
type globalFlags struct {
	verbosity     int
	quiet         bool
	color         ColorMode
	noInteraction bool
	env           string
}

// colorFlag is --ansi or --no-ansi: both write one shared ColorMode, so the
// last flag on the command line wins.
type colorFlag struct {
	mode *ColorMode
	set  ColorMode
}

func (f colorFlag) String() string {
	return strconv.FormatBool(*f.mode == f.set)
}

func (f colorFlag) Set(s string) error {
	on, err := strconv.ParseBool(s)
	if err != nil {
		return err
	}
	switch {
	case on:
		*f.mode = f.set
	case *f.mode == f.set:
		*f.mode = ColorAuto
	}
	return nil
}

func (f colorFlag) Type() string { return "bool" }

// register adds the global options to the root's persistent flags.
func (gf *globalFlags) register(fs *pflag.FlagSet) {
	fs.CountVarP(&gf.verbosity, flagVerbose, "v", "Increase verbosity (-v, -vv or -vvv)")
	fs.BoolVarP(&gf.quiet, flagQuiet, "q", false, "Do not output any message")
	fs.Var(colorFlag{mode: &gf.color, set: ColorAlways}, flagANSI, "Force ANSI output")
	fs.Lookup(flagANSI).NoOptDefVal = "true"
	fs.Var(colorFlag{mode: &gf.color, set: ColorNever}, flagNoANSI, "Disable ANSI output")
	fs.Lookup(flagNoANSI).NoOptDefVal = "true"
	fs.BoolVarP(&gf.noInteraction, flagNoInteraction, "n", false, "Do not ask any interactive question")
	fs.StringVar(&gf.env, flagEnv, "", "The environment the command runs under")
}

func (gf *globalFlags) globals() Globals {
	return normalize(Globals{
		Verbosity:     gf.verbosity,
		Quiet:         gf.quiet,
		Color:         gf.color,
		NoInteraction: gf.noInteraction,
		Env:           gf.env,
	})
}

// resetFlags puts every persistent flag of root back to its default, so a
// root executed twice (tests, Execute) does not keep the previous run's
// globals: pflag count flags add to their current value.
func resetFlags(root *cobra.Command) {
	root.PersistentFlags().VisitAll(func(f *pflag.Flag) {
		_ = f.Value.Set(f.DefValue)
		f.Changed = false
	})
}

// globalOption is one line of the global options block in list and help.
type globalOption struct {
	flags       string
	description string
}

// globalOptions are the global option lines of the list (D-13).
var globalOptions = []globalOption{
	{"-h, --help", "Display help for the given command"},
	{"-q, --quiet", "Do not output any message"},
	{"-v|vv|vvv", "Increase verbosity"},
	{"    --ansi|no-ansi", "Force (or disable) ANSI output"},
	{"-n, --no-interaction", "Do not ask any interactive question"},
	{"    --env", "The environment the command runs under"},
}