package service

import (
	"context"
	"fmt"
	"os"
	"strings"
	"time"

	"ai-agent-scaffold-go/internal/config"
	"ai-agent-scaffold-go/internal/llm"
	"ai-agent-scaffold-go/internal/model"
)

// AssembleAll 从配置表批量组装 Agent
func AssembleAll(ctx context.Context, tables map[string]model.AiAgentConfigTable, timeout time.Duration) ([]model.RegisteredAgent, error) {
	var agents []model.RegisteredAgent
	for _, table := range tables {
		agent, err := assembleOne(ctx, table, timeout)
		if err != nil {
			return nil, fmt.Errorf("assemble %s: %w", table.AppName, err)
		}
		agents = append(agents, *agent)
	}
	return agents, nil
}

// assembleOne 组装单个 Agent 配置
func assembleOne(ctx context.Context, table model.AiAgentConfigTable, timeout time.Duration) (*model.RegisteredAgent, error) {
	apiCfg := table.Module.AiAPI
	completionsURL := strings.TrimRight(apiCfg.BaseURL, "/") + "/" + strings.TrimLeft(apiCfg.CompletionsPath, "/")

	// 1. 创建 OpenAI 客户端
	client := llm.NewOpenAIClient(completionsURL, apiCfg.APIKey, table.Module.ChatModel.Model, timeout)

	// 2. 创建 ChatModel（当前无外部工具，后续可扩展）
	chatModel := llm.NewChatModelAdapter(client, nil)

	// 3. 构建 Agent 映射表
	agentMap := map[string]model.Agent{}
	for _, agentCfg := range table.Module.Agents {
		agent := NewLLMAgent(agentCfg.Name, agentCfg.Instruction, agentCfg.Description, agentCfg.OutputKey, chatModel)
		agentMap[agentCfg.Name] = agent
	}

	// 4. 构建 Workflow Agent
	for _, wfCfg := range table.Module.AgentWorkflows {
		subs := make([]model.Agent, 0, len(wfCfg.SubAgents))
		for _, subName := range wfCfg.SubAgents {
			sub, ok := agentMap[subName]
			if !ok {
				return nil, fmt.Errorf("workflow %q references unknown agent %q", wfCfg.Name, subName)
			}
			subs = append(subs, sub)
		}
		var wfAgent model.Agent
		switch wfCfg.Type {
		case model.WorkflowTypeSequential:
			wfAgent = NewSequentialAgent(wfCfg.Name, wfCfg.Description, subs)
		case model.WorkflowTypeParallel:
			wfAgent = NewParallelAgent(wfCfg.Name, wfCfg.Description, subs)
		case model.WorkflowTypeLoop:
			wfAgent = NewLoopAgent(wfCfg.Name, wfCfg.Description, subs, wfCfg.MaxIterations)
		default:
			return nil, fmt.Errorf("unknown workflow type: %s", wfCfg.Type)
		}
		agentMap[wfCfg.Name] = wfAgent
	}

	// 5. 解析入口 Agent
	entryName := table.Module.Runner.AgentName
	entryAgent, ok := agentMap[entryName]
	if !ok {
		return nil, fmt.Errorf("entry agent %q not found", entryName)
	}

	// 6. 创建 Runner
	runner := NewRunner(table.AppName, entryAgent)

	return &model.RegisteredAgent{
		AppName:   table.AppName,
		AgentID:   table.Agent.AgentID,
		AgentName: table.Agent.AgentName,
		AgentDesc: table.Agent.AgentDesc,
		Runner:    runner,
	}, nil
}

// LoadAndAssemble 从配置文件路径列表加载并组装所有 Agent
func LoadAndAssemble(ctx context.Context, paths []string, timeout time.Duration) ([]model.RegisteredAgent, error) {
	merged := make(map[string]model.AiAgentConfigTable)
	for _, raw := range paths {
		path := strings.TrimSpace(raw)
		if path == "" {
			continue
		}
		expanded := os.ExpandEnv(path)
		tables, err := config.LoadAgentTablesFile(expanded)
		if err != nil {
			return nil, err
		}
		for name, table := range tables {
			merged[name] = table
		}
	}
	if len(merged) == 0 {
		return nil, fmt.Errorf("no agent tables loaded")
	}
	return AssembleAll(ctx, merged, timeout)
}