package agent

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

	"laodingbot/internal/llm"
	"laodingbot/internal/logger"
	"laodingbot/internal/memory"
	"laodingbot/internal/tools"
)

type Orchestrator struct {
	llm          llm.Client
	store        *memory.SQLiteStore
	tools        *tools.Registry
	soul         string
	skillsDoc    string
	reactMaxStep int
	log          *logger.Logger
}

func NewOrchestrator(
	llmClient llm.Client,
	store *memory.SQLiteStore,
	registry *tools.Registry,
	soul string,
	skillsDoc string,
	reactMaxStep int,
	log *logger.Logger,
) *Orchestrator {
	if reactMaxStep <= 0 {
		reactMaxStep = 4
	}
	return &Orchestrator{
		llm:          llmClient,
		store:        store,
		tools:        registry,
		soul:         soul,
		skillsDoc:    skillsDoc,
		reactMaxStep: reactMaxStep,
		log:          log,
	}
}

func (o *Orchestrator) HandleMessage(ctx context.Context, chatID, userID, text string) (string, error) {
	if o.log != nil {
		o.log.Infof("handle message chat_id=%s user_id=%s text_len=%d", chatID, userID, len(text))
	}
	if err := o.store.SaveMessage(chatID, userID, "user", text); err != nil {
		if o.log != nil {
			o.log.Errorf("save user message failed chat_id=%s err=%v", chatID, err)
		}
		return "", err
	}

	if strings.HasPrefix(strings.TrimSpace(text), "/tool ") {
		if o.log != nil {
			o.log.Debugf("detected tool command chat_id=%s", chatID)
		}
		response, err := o.handleToolCommand(ctx, strings.TrimSpace(strings.TrimPrefix(text, "/tool ")))
		if err != nil {
			if o.log != nil {
				o.log.Errorf("tool command failed chat_id=%s err=%v", chatID, err)
			}
			return "", err
		}
		if err := o.store.SaveMessage(chatID, userID, "assistant", response); err != nil {
			if o.log != nil {
				o.log.Errorf("save assistant tool response failed chat_id=%s err=%v", chatID, err)
			}
			return "", err
		}
		if o.log != nil {
			o.log.Infof("tool command success chat_id=%s response_len=%d", chatID, len(response))
		}
		return response, nil
	}

	recent, err := o.store.LoadRecent(chatID, 16)
	if err != nil {
		if o.log != nil {
			o.log.Errorf("load recent failed chat_id=%s err=%v", chatID, err)
		}
		return "", err
	}
	compressed := memory.CompressForPrompt(recent, 6000)
	if o.log != nil {
		o.log.Debugf("prompt context prepared chat_id=%s recent_count=%d compressed_len=%d", chatID, len(recent), len(compressed))
	}

	response, err := o.runReAct(ctx, compressed, text)
	if err != nil {
		if o.log != nil {
			o.log.Errorf("llm generate failed chat_id=%s err=%v", chatID, err)
		}
		return "", err
	}

	if err := o.store.SaveMessage(chatID, userID, "assistant", response); err != nil {
		if o.log != nil {
			o.log.Errorf("save assistant response failed chat_id=%s err=%v", chatID, err)
		}
		return "", err
	}
	if o.log != nil {
		o.log.Infof("message handled chat_id=%s response_len=%d", chatID, len(response))
	}
	return response, nil
}

type reactDecision struct {
	Thought     string `json:"thought"`
	Action      string `json:"action"`
	ActionInput string `json:"action_input"`
	Final       string `json:"final"`
}

func (o *Orchestrator) runReAct(ctx context.Context, compressedContext, userInput string) (string, error) {
	systemPrompt := strings.Join([]string{
		"你是一个个人自动化助手，必须遵循如下人格设定并保持一致：",
		o.soul,
		"",
		"当前可用 skills 文档：",
		o.skillsDoc,
		"",
		"你必须使用 ReAct 模式做决策。",
		"如果问题需要外部信息（如文件系统、目录内容、命令执行），优先通过工具获取证据再回答。",
		"当用户询问目录中文件时，应优先使用 shell 工具（例如 ls/find）。",
		"你的输出必须是 JSON，对象字段为 thought, action, action_input, final。",
		"规则：",
		"1) 当需要调工具时：final 置空，action 为 shell 或 file，action_input 为工具输入。",
		"2) 当可以最终回答时：action 置 none，action_input 置空，final 填最终回复。",
		"3) 不要输出 JSON 之外内容。",
	}, "\n")

	scratchpad := ""
	for step := 1; step <= o.reactMaxStep; step++ {
		prompt := strings.Join([]string{
			"历史上下文：",
			compressedContext,
			"",
			"用户问题：",
			userInput,
			"",
			"当前推理记录（按时间顺序）：",
			scratchpad,
			"",
			fmt.Sprintf("请输出下一步 JSON 决策。当前步骤: %d/%d", step, o.reactMaxStep),
		}, "\n")

		raw, err := o.llm.Generate(ctx, systemPrompt, prompt)
		if err != nil {
			return "", err
		}
		decision, err := parseDecision(raw)
		if err != nil {
			if o.log != nil {
				o.log.Warnf("react parse failed, use raw as final err=%v", err)
			}
			return strings.TrimSpace(raw), nil
		}

		action := strings.ToLower(strings.TrimSpace(decision.Action))
		if action == "" {
			action = "none"
		}

		if action == "none" {
			finalText := strings.TrimSpace(decision.Final)
			if finalText == "" {
				finalText = "我已完成思考，但当前没有足够信息给出稳定结论。"
			}
			return finalText, nil
		}

		tool, ok := o.tools.Get(action)
		if !ok {
			scratchpad += fmt.Sprintf("Step %d Thought: %s\nStep %d Observation: tool %s 不存在\n", step, decision.Thought, step, action)
			continue
		}

		toolOut, toolErr := tool.Call(ctx, decision.ActionInput)
		obs := strings.TrimSpace(toolOut)
		if obs == "" {
			obs = "(empty output)"
		}
		if toolErr != nil {
			obs = obs + "\nERROR: " + toolErr.Error()
		}
		if len(obs) > 2000 {
			obs = obs[:2000]
		}
		scratchpad += fmt.Sprintf("Step %d Thought: %s\nStep %d Action: %s\nStep %d ActionInput: %s\nStep %d Observation: %s\n", step, decision.Thought, step, action, step, decision.ActionInput, step, obs)
	}

	return "我尝试了多轮思考与工具调用，但仍未得到稳定结论。请给我更具体的约束或允许我继续尝试。", nil
}

func parseDecision(raw string) (reactDecision, error) {
	raw = strings.TrimSpace(raw)
	raw = strings.TrimPrefix(raw, "```json")
	raw = strings.TrimPrefix(raw, "```")
	raw = strings.TrimSuffix(raw, "```")
	raw = strings.TrimSpace(raw)

	start := strings.Index(raw, "{")
	end := strings.LastIndex(raw, "}")
	if start < 0 || end < start {
		return reactDecision{}, fmt.Errorf("no json object found")
	}
	raw = raw[start : end+1]

	var out reactDecision
	if err := json.Unmarshal([]byte(raw), &out); err != nil {
		return reactDecision{}, err
	}
	return out, nil
}

func (o *Orchestrator) handleToolCommand(ctx context.Context, payload string) (string, error) {
	parts := strings.SplitN(payload, " ", 2)
	if len(parts) < 2 {
		if o.log != nil {
			o.log.Warnf("invalid tool command payload=%q", payload)
		}
		return "", fmt.Errorf("tool command format: /tool <name> <input>")
	}
	name := strings.TrimSpace(parts[0])
	input := parts[1]
	if o.log != nil {
		o.log.Debugf("dispatch tool name=%s input_len=%d", name, len(input))
	}
	t, ok := o.tools.Get(name)
	if !ok {
		if o.log != nil {
			o.log.Warnf("unknown tool requested name=%s", name)
		}
		return "", fmt.Errorf("unknown tool: %s", name)
	}
	return t.Call(ctx, input)
}