package agent

import (
	"context"
	"time"

	"chat-agent-system/internal/config"
)

type Request struct {
	WorkDir      string        `json:"work_dir"`
	Prompt       string        `json:"prompt"`
	Instructions string        `json:"instructions"`
	Targets      []string      `json:"targets"`
	Timeout      time.Duration `json:"timeout"`
}

type Result struct {
	Success     bool              `json:"success"`
	Patches     map[string][]byte `json:"patches"`
	Logs        string            `json:"logs"`
	ErrorReason string            `json:"error_reason"`
	// Retryable marks a provider-transient failure that may receive a
	// fresh step invocation. Permanent missing deliverables stay false.
	Retryable bool `json:"retryable,omitempty"`
}

type Backend interface {
	Name() string
	Execute(ctx context.Context, req Request) (*Result, error)
}

func NewBackend(name string, cfg *config.Config) Backend {
	var inner Backend
	switch name {
	case "pi-agent":
		inner = &PiAgentBackend{cfg: cfg}
	case "cursor-cli":
		inner = &CursorCLIBackend{cfg: cfg}
	default:
		inner = &StubBackend{}
	}
	max := 8
	if cfg != nil && cfg.MaxConcurrentAgents > 0 {
		max = cfg.MaxConcurrentAgents
	}
	return WrapWithConcurrencyLimit(inner, max)
}