package services

import (
	"context"
	"encoding/json"
	"fmt"
	"sort"
	"strings"
	"sync"

	"code.tczkiot.com/wlw/ai-agent/contract"
)

var BusinessActionToolService = &businessActionToolService{}

type businessActionToolService struct {
	mu    sync.RWMutex
	tools map[string]contract.BusinessActionTool
}

func SetBusinessActionTools(tools []contract.BusinessActionTool) error {
	registered := make(map[string]contract.BusinessActionTool, len(tools))
	for _, tool := range tools {
		tool.Code = strings.TrimSpace(tool.Code)
		tool.Description = strings.TrimSpace(tool.Description)
		if tool.Code == "" {
			return fmt.Errorf("ai-agent: business action tool code is required")
		}
		if !strings.HasPrefix(tool.Code, "business/") {
			return fmt.Errorf("ai-agent: business action tool code must start with business/: %s", tool.Code)
		}
		if tool.Description == "" {
			return fmt.Errorf("ai-agent: business action tool description is required: %s", tool.Code)
		}
		if tool.Preview == nil || tool.Execute == nil {
			return fmt.Errorf("ai-agent: business action tool preview and executor are required: %s", tool.Code)
		}
		if _, exists := registered[tool.Code]; exists {
			return fmt.Errorf("ai-agent: duplicate business action tool code: %s", tool.Code)
		}
		if tool.InputSchema == nil {
			tool.InputSchema = map[string]any{"type": "object", "properties": map[string]any{}}
		}
		registered[tool.Code] = tool
	}

	BusinessActionToolService.mu.Lock()
	BusinessActionToolService.tools = registered
	BusinessActionToolService.mu.Unlock()
	return nil
}

func (s *businessActionToolService) ListForCustomerType(customerType string) []contract.BusinessActionTool {
	s.mu.RLock()
	defer s.mu.RUnlock()
	ret := make([]contract.BusinessActionTool, 0, len(s.tools))
	for _, tool := range s.tools {
		if businessActionToolSupportsCustomerType(tool, customerType) {
			ret = append(ret, tool)
		}
	}
	sort.Slice(ret, func(i, j int) bool { return ret[i].Code < ret[j].Code })
	return ret
}

func (s *businessActionToolService) ResolveForCustomerType(code, customerType string) (contract.BusinessActionTool, bool) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	tool, ok := s.tools[strings.TrimSpace(code)]
	if !ok || !businessActionToolSupportsCustomerType(tool, customerType) {
		return contract.BusinessActionTool{}, false
	}
	return tool, true
}

func (s *businessActionToolService) Resolve(code string) (contract.BusinessActionTool, bool) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	tool, ok := s.tools[strings.TrimSpace(code)]
	return tool, ok
}

func (s *businessActionToolService) Preview(ctx context.Context, tool contract.BusinessActionTool, businessContext contract.BusinessReadContext, arguments map[string]any) (string, error) {
	return tool.Preview(ctx, businessContext, arguments)
}

func (s *businessActionToolService) Execute(ctx context.Context, conversationID, aiAgentID int64, idempotencyKey string, tool contract.BusinessActionTool, businessContext contract.BusinessReadContext, arguments map[string]any) (*contract.BusinessActionResult, bool, error) {
	businessContext.CheckPointID = strings.TrimSpace(idempotencyKey)
	if tool.AuthorizeConfirmation != nil {
		if err := tool.AuthorizeConfirmation(ctx, businessContext, arguments, businessContext.CheckPointID); err != nil {
			return nil, false, err
		}
	}
	claim, err := AgentToolInvocationService.Claim(conversationID, aiAgentID, tool.Code, idempotencyKey)
	if err != nil {
		return nil, false, contract.NewBusinessActionError("操作请求记录创建失败，本次操作未执行，请稍后重试。", err)
	}
	if claim == nil || claim.Item == nil {
		err := fmt.Errorf("business action invocation could not be claimed")
		return nil, false, contract.NewBusinessActionError("操作请求无效，本次操作未执行，请重新发起。", err)
	}
	if claim.Completed {
		result := &contract.BusinessActionResult{}
		if err := json.Unmarshal([]byte(claim.Item.ResultData), result); err != nil {
			return nil, true, contract.NewBusinessActionError("操作已完成，但结果读取失败，请勿重复操作并联系人工客服核对。", err)
		}
		return result, true, nil
	}
	if claim.UnknownOutcome {
		err := fmt.Errorf("business action outcome requires reconciliation: %s", tool.Code)
		return nil, true, contract.NewUnknownOutcomeBusinessActionError("上次操作结果尚未确认，请勿重复操作，并联系人工客服核对。", err)
	}
	if !claim.Acquired {
		err := fmt.Errorf("business action is already running: %s", tool.Code)
		return nil, false, contract.NewBusinessActionError("操作正在处理中，请勿重复提交，请稍后查看结果。", err)
	}
	result, err := tool.Execute(ctx, businessContext, arguments)
	if err != nil {
		if businessActionFailureIsRetryable(ctx, err) {
			_ = AgentToolInvocationService.FailRetryable(claim.Item, err)
		} else {
			_ = AgentToolInvocationService.MarkUnknownOutcome(claim.Item, err)
		}
		return nil, false, err
	}
	if result == nil || strings.TrimSpace(result.Message) == "" {
		err = fmt.Errorf("business action returned an empty result: %s", tool.Code)
		_ = AgentToolInvocationService.MarkUnknownOutcome(claim.Item, err)
		return nil, false, contract.NewBusinessActionError("业务系统未返回操作结果，本次操作未完成，请联系人工客服核对。", err)
	}
	encoded, err := json.Marshal(result)
	if err != nil {
		// The host operation has already completed. Persist at least the customer
		// message and never mark the invocation retryable, which could execute the
		// same paid action twice.
		encoded, _ = json.Marshal(&contract.BusinessActionResult{Message: result.Message})
	}
	if err := AgentToolInvocationService.Complete(claim.Item, string(encoded)); err != nil {
		// The external write may already have committed. Never leave the invocation
		// eligible for replay; persist an explicit reconciliation state whenever the
		// result cannot be durably recorded.
		_ = AgentToolInvocationService.MarkUnknownOutcome(claim.Item, err)
		return nil, false, contract.NewBusinessActionError("业务操作可能已经成功，但结果记录失败。请勿重复操作，并联系人工客服核对。", err)
	}
	return result, false, nil
}

func businessActionToolSupportsCustomerType(tool contract.BusinessActionTool, customerType string) bool {
	if len(tool.CustomerTypes) == 0 {
		return true
	}
	for _, candidate := range tool.CustomerTypes {
		if strings.EqualFold(strings.TrimSpace(candidate), strings.TrimSpace(customerType)) {
			return true
		}
	}
	return false
}