package contract

import (
	"context"
	"errors"
)

type BusinessActionFailureOutcome string

const (
	// BusinessActionFailureRetryable means execution failed before the host
	// operation could have produced a side effect. The same idempotency key may
	// be claimed again.
	BusinessActionFailureRetryable BusinessActionFailureOutcome = "retryable_failed"
	// BusinessActionFailureUnknown means the host may have committed the side
	// effect even though Agent Desk did not receive a definitive response. Such
	// an invocation must be reconciled instead of replayed automatically.
	BusinessActionFailureUnknown BusinessActionFailureOutcome = "unknown_outcome"
)

// BusinessActionResult is the customer-safe result returned after a confirmed
// host business operation. Message is sent to the customer verbatim; Data is
// retained only for idempotent replay and future structured clients.
type BusinessActionResult struct {
	Message string `json:"message"`
	Data    any    `json:"data,omitempty"`
}

// BusinessActionError separates a customer-safe explanation from its internal
// cause so model observations and chat replies never expose infrastructure
// errors returned by the host application.
type BusinessActionError struct {
	Message string
	Cause   error
	Outcome BusinessActionFailureOutcome
}

func (e *BusinessActionError) Error() string {
	return e.Message
}

func (e *BusinessActionError) Unwrap() error {
	return e.Cause
}

func NewBusinessActionError(message string, cause error) error {
	return &BusinessActionError{Message: message, Cause: cause, Outcome: BusinessActionFailureUnknown}
}

func NewRetryableBusinessActionError(message string, cause error) error {
	return &BusinessActionError{Message: message, Cause: cause, Outcome: BusinessActionFailureRetryable}
}

func NewUnknownOutcomeBusinessActionError(message string, cause error) error {
	return &BusinessActionError{Message: message, Cause: cause, Outcome: BusinessActionFailureUnknown}
}

func BusinessActionErrorOutcome(err error) BusinessActionFailureOutcome {
	var actionErr *BusinessActionError
	if errors.As(err, &actionErr) {
		return actionErr.Outcome
	}
	return ""
}

// BusinessActionTool lets the host expose a narrowly scoped write operation.
// Preview must perform read-only validation and produce the exact confirmation
// prompt. Execute must independently reload and validate all mutable business
// state before committing the operation.
type BusinessActionTool struct {
	Code          string
	Description   string
	CustomerTypes []string
	InputSchema   map[string]any
	// MatchIntent lets the host identify an unambiguous customer command that
	// must enter the confirmation flow without relying on the language model to
	// select a tool. It must be side-effect free.
	MatchIntent func(string) bool
	Preview     func(context.Context, BusinessReadContext, map[string]any) (string, error)
	// BindConfirmation binds the generated server checkpoint and canonical
	// arguments to the verified request that prepared the action.
	BindConfirmation func(context.Context, BusinessReadContext, map[string]any, string) error
	// AuthorizeConfirmation re-verifies the current confirmation request and
	// the previously bound checkpoint immediately before idempotency claiming.
	AuthorizeConfirmation func(context.Context, BusinessReadContext, map[string]any, string) error
	Execute               func(context.Context, BusinessReadContext, map[string]any) (*BusinessActionResult, error)
}