// Command harness is the MOPAC harness CLI. v0 surface: `harness once`.
package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"syscall"

	"git.knownelement.com/reachableceo/MOPAC/harness/internal/config"
	"git.knownelement.com/reachableceo/MOPAC/harness/internal/loop"
)

const usage = `MOPAC harness (v0)

Usage:
  harness once [-config PATH] [-dry-run] [-demo] [-task-id ID]

once runs ONE conductor iteration and exits (chain by re-invoking; no daemon):
  intake (Redmine scope, or the [demo] issue) -> plan/model routing ->
  bounded turn via LiteLLM -> REPORT file writeback.

Flags:
  -config PATH   config file (default $HARNESS_CONFIG or ./harness.toml)
  -dry-run       intake + plan only; no LLM call, no REPORT
  -demo          run the [demo] issue instead of Redmine intake
  -task-id ID    run only the task/issue with this id

Exit codes:
  0 ok (including "no tasks in scope")
  1 usage / config / routing / writeback error
  2 intake error
  4 llm / turn error
`

func main() {
	os.Exit(run(os.Args[1:]))
}

func run(args []string) int {
	if len(args) == 0 {
		fmt.Fprint(os.Stderr, usage)
		return 1
	}
	switch args[0] {
	case "help", "-h", "--help":
		fmt.Print(usage)
		return 0
	case "once":
		return runOnce(args[1:])
	default:
		fmt.Fprintf(os.Stderr, "harness: unknown command %q\n\n%s", args[0], usage)
		return 1
	}
}

func runOnce(args []string) int {
	fs := flag.NewFlagSet("once", flag.ContinueOnError)
	cfgPath := fs.String("config", "", "config file path")
	dryRun := fs.Bool("dry-run", false, "intake + plan only, no LLM call")
	demo := fs.Bool("demo", false, "use the [demo] issue instead of Redmine")
	taskID := fs.String("task-id", "", "run only this task id")
	if err := fs.Parse(args); err != nil {
		return 1
	}
	if fs.NArg() > 0 {
		fmt.Fprintf(os.Stderr, "harness: unexpected argument %q\n", fs.Arg(0))
		return 1
	}

	if *cfgPath == "" {
		*cfgPath = os.Getenv("HARNESS_CONFIG")
	}
	if *cfgPath == "" {
		*cfgPath = "harness.toml"
	}
	cfg, err := config.Load(*cfgPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "harness: %v\n", err)
		return 1
	}
	conductor, err := loop.New(cfg, os.Stdout)
	if err != nil {
		fmt.Fprintf(os.Stderr, "harness: %v\n", err)
		return 1
	}

	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	_, err = conductor.Once(ctx, loop.OnceOpts{
		DryRun: *dryRun,
		Demo:   *demo,
		TaskID: *taskID,
	})
	if err != nil {
		fmt.Fprintf(os.Stderr, "harness: %v\n", err)
		switch {
		case errors.Is(err, loop.ErrIntake):
			return 2
		case errors.Is(err, loop.ErrLLM):
			return 4
		default:
			return 1
		}
	}
	return 0
}