// SPDX-License-Identifier: GPL-3.0-or-later

package main

import (
	"fmt"
	"io"
	"path/filepath"
	"strings"
	"time"

	"krino/internal/config"
	"krino/internal/engine"
	"krino/internal/xdg"
)

// minAgeOverride parses --min-age: a duration in krino's own units (30s,
// 2m, 1h, 1d, 1w), or a bare 0. set is false when the flag was not given.
// Checked before any config is read, as every flag is.
func minAgeOverride(g *globals) (d time.Duration, set bool, err error) {
	switch {
	case !g.minAgeSet:
		return 0, false, nil
	case g.minAge == "":
		return 0, false, fmt.Errorf("--min-age: needs a duration, like 0, 30m or 1d")
	case g.minAge == "0":
		return 0, true, nil
	}
	d, err = config.ParseDuration(g.minAge)
	if err != nil {
		return 0, false, fmt.Errorf("--min-age: %v", err)
	}
	return d, true, nil
}

// refuseUnusedFlags refuses the global flags a command does not use -
// -y and -n unless usesYesDry, and --json and -v - instead of silently
// ignoring them, so "krino -n new ...", meant as a preview, cannot write
// config (re-review cli F4). It reports whether it refused.
func refuseUnusedFlags(g *globals, stderr io.Writer, cmd string, usesYesDry bool) (int, bool) {
	var given []string
	if !usesYesDry && g.yes {
		given = append(given, "-y")
	}
	if !usesYesDry && g.dry {
		given = append(given, "-n")
	}
	if g.json {
		given = append(given, "--json")
	}
	if g.verbose {
		given = append(given, "-v")
	}
	if len(given) == 0 {
		return 0, false
	}
	return usageError(stderr, fmt.Sprintf("%s does not take %s", cmd, strings.Join(given, ", "))), true
}

// cacheDir is where every directory's keyword cache lives (spec §6.1).
func cacheDir() string {
	return filepath.Join(xdg.CacheHome(), "krino")
}

// applyMinAge sets every loaded directory's min-age to d, for this run only.
func applyMinAge(e *engine.Engine, d time.Duration) {
	for _, dir := range e.Dirs {
		dir.Settings.MinAge = d
	}
}

// mainFile is -c FILE, or the default krino.conf.
func mainFile(g *globals) string {
	if g.conf != "" {
		return xdg.Expand(g.conf)
	}
	return config.DefaultFile()
}

// usageError reports a command-line mistake and returns exit status 2.
func usageError(stderr io.Writer, msg string) int {
	fmt.Fprintf(stderr, "krino: %s\n", msg)
	fmt.Fprintln(stderr, "run 'krino -h' for help")
	return 2
}

// printDiags prints config problems with ~ for the home directory, then a count.
func printDiags(stderr io.Writer, errs []*config.Diag) {
	for _, e := range errs {
		d := *e
		d.File = xdg.Abbrev(d.File)
		fmt.Fprintln(stderr, &d)
	}
	if len(errs) == 1 {
		fmt.Fprintln(stderr, "krino: 1 problem found")
	} else {
		fmt.Fprintf(stderr, "krino: %d problems found\n", len(errs))
	}
}

// describeActions renders a rule's actions briefly, as in: move PDF, stop.
func describeActions(r *config.Rule) string {
	var parts []string
	for _, a := range r.Actions {
		if a.Arg == "" {
			parts = append(parts, a.Kind.String())
		} else {
			parts = append(parts, a.Kind.String()+" "+a.Arg)
		}
	}
	if r.Stop {
		parts = append(parts, "stop")
	}
	return strings.Join(parts, ", ")
}