// Package cli implements the mglpi command line: a thin, machine-friendly
// front end over the glpi library. Connection settings come from
// MGLPI_URL / MGLPI_APP_TOKEN / MGLPI_USER_TOKEN env vars (plus optional
// MGLPI_PROFILE_ID for agent mode) or a 0600 --config env file — tokens
// are never flag values and never logged. Every command accepts -o json
// for machine output. Exit codes: 0 ok, 1 usage/config, 2 API error
// (single-line stderr carrying the http status, parseable).
package cli

import (
	"flag"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"

	"git.knownelement.com/ukrrs/mopac-glpi-go/internal/config"
	"git.knownelement.com/ukrrs/mopac-glpi-go/glpi"
)

const usage = `mglpi: GLPI/CMDB CLI (stdlib-only, library-backed)

Usage:
  mglpi whoami [-o json]
  mglpi change create --title T [--urgency N] [--impact N] [--profile N]
                      [--content FILE|-] [-o json]
  mglpi change show ID [-o json]
  mglpi change list [--status N|NAME] [-o json]
  mglpi change transition ID STATUS (STATUS numeric or: new evaluation
                    approval test qualification waiting accepted assigned
                    planned pending solved closed) [-o json]
  mglpi change followup ID [--content FILE|-] [-o json]
  mglpi ci search TYPE TERM [-o json]
  mglpi ci show TYPE ID [-o json]
  mglpi help

Connection: MGLPI_URL + MGLPI_APP_TOKEN + MGLPI_USER_TOKEN env vars, or
--config PATH pointing at a 0600 env file with the same keys. Tokens
never appear in flags, logs, or error output.

Agent mode: --profile N (or MGLPI_PROFILE_ID in the env file) switches
the session's active profile (e.g. 5 = Hotliner) right after
InitSession — servers that gate operations per profile then accept the
calls. whoami never switches.

change create / change followup read their body from stdin by default
(--content FILE to read a file instead).

Exit codes: 0 ok, 1 usage/config error, 2 API error (stderr: one line,
"http NNN" included).`

// Run executes one command; it returns the process exit code.
func Run(args []string, stdout, stderr io.Writer) int {
	if len(args) == 0 {
		fmt.Fprint(stderr, usage)
		return 1
	}
	// Hoist a leading global --config PATH onto the subcommand (the
	// subcommand flag sets already accept it anywhere).
	var hoisted []string
	for len(args) >= 2 && (args[0] == "--config" || args[0] == "-config") {
		hoisted = append(hoisted, args[0], args[1])
		args = args[2:]
	}
	if len(hoisted) > 0 {
		if len(args) == 0 {
			fmt.Fprint(stderr, usage)
			return 1
		}
		args = append(args, hoisted...)
	}
	switch args[0] {
	case "help", "-h", "--help":
		fmt.Fprint(stdout, usage)
		return 0
	case "whoami":
		return cmdWhoami(args[1:], stdout, stderr)
	case "change":
		return cmdChange(args[1:], stdout, stderr)
	case "ci":
		return cmdCI(args[1:], stdout, stderr)
	default:
		fmt.Fprintf(stderr, "mglpi: unknown command %q\n\n%s\n", args[0], usage)
		return 1
	}
}

// newFlags builds a quiet flag set with the shared --config and -o flags.
func newFlags(name string, stderr io.Writer) (*flag.FlagSet, *string, *string) {
	fs := flag.NewFlagSet(name, flag.ContinueOnError)
	fs.SetOutput(io.Discard)
	cfg := fs.String("config", "", "env file with MGLPI_URL/MGLPI_APP_TOKEN/MGLPI_USER_TOKEN (must be 0600)")
	out := fs.String("o", "text", "output format: text|json")
	return fs, cfg, out
}

// parseArgs parses flags that may appear AFTER positionals (the standard
// flag package stops at the first positional; mglpi's documented surface
// is "change show ID -o json", "ci search TYPE TERM"). It returns the
// positional arguments.
func parseArgs(fs *flag.FlagSet, args []string) ([]string, error) {
	var positionals []string
	rest := args
	for {
		if err := fs.Parse(rest); err != nil {
			return nil, err
		}
		got := fs.Args()
		i := 0
		for i < len(got) && (got[i] == "-" || !strings.HasPrefix(got[i], "-")) {
			i++
		}
		positionals = append(positionals, got[:i]...)
		if i == len(got) {
			return positionals, nil
		}
		rest = got[i:]
	}
}

// client resolves config (env + optional 0600 file) and builds the
// client, resolving the effective agent profile (flag wins over the
// MGLPI_PROFILE_ID config key). A non-nil error means exit 1; profile
// application (an API op) surfaces later as exit 2.
func client(cfgPath string, profileFlag int) (*glpi.Client, int, error) {
	if cfgPath == "" {
		cfgPath = os.Getenv("MGLPI_CONFIG")
	}
	if cfgPath == "" {
		if home, err := os.UserHomeDir(); err == nil {
			cand := filepath.Join(home, ".config", "mglpi", "env")
			if _, err := os.Stat(cand); err == nil {
				cfgPath = cand
			}
		}
	}
	cfg, _, err := config.Load(cfgPath)
	if err != nil {
		return nil, 0, err
	}
	profile := profileFlag
	if profile == 0 {
		profile = cfg.ProfileID
	}
	return glpi.New(glpi.Config{
		BaseURL:   cfg.BaseURL,
		AppToken:  cfg.AppToken,
		UserToken: cfg.UserToken,
	}), profile, nil
}

// apiErr reports an API failure the mglpi way: one line, exit 2.
func apiErr(stderr io.Writer, err error) int {
	fmt.Fprintf(stderr, "mglpi: %v\n", err)
	return 2
}

// usageErr reports a usage/config failure: one line, exit 1.
func usageErr(stderr io.Writer, format string, args ...any) int {
	fmt.Fprintf(stderr, "mglpi: "+format+"\n", args...)
	return 1
}

// emitJSON pretty-prints v for -o json.
func emitJSON(stdout io.Writer, v any) {
	b, err := marshalIndent(v)
	if err != nil {
		return // library types are JSON-clean by construction
	}
	stdout.Write(b)
	fmt.Fprintln(stdout)
}