package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

	"gopkg.in/yaml.v3"
)

var registeredTools = make(map[string]*ToolDef)

func RegisterTool(td *ToolDef) {
	registeredTools[td.Name] = td
}

func ListRegisteredTools() []*ToolDef {
	list := make([]*ToolDef, 0, len(registeredTools))
	for _, td := range registeredTools {
		list = append(list, td)
	}
	return list
}

func GetToolDefs(names []string) []ToolDef {
	defs := make([]ToolDef, 0, len(names))
	for _, name := range names {
		if td, ok := registeredTools[name]; ok {
			defs = append(defs, *td)
		}
	}
	return defs
}

func safeMemoryPath(path string) (string, error) {
	cleanPath := filepath.Clean(path)
	fullPath := filepath.Join(ConfigDir(), cleanPath)

	realPath, err := filepath.EvalSymlinks(fullPath)
	if err != nil {
		if !os.IsNotExist(err) {
			return "", fmt.Errorf("路径解析失败: %w", err)
		}
		realPath = fullPath
	}

	rel, err := filepath.Rel(ConfigDir(), realPath)
	if err != nil || strings.HasPrefix(rel, "..") {
		return "", fmt.Errorf("路径越界: %s", path)
	}

	return fullPath, nil
}

func ExecuteTool(tc ToolCall) (string, error) {
	td, ok := registeredTools[tc.Function.Name]
	if !ok {
		return "", fmt.Errorf("未知工具: %s", tc.Function.Name)
	}

	var args map[string]any
	if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {
		return "", fmt.Errorf("解析工具参数失败: %w", err)
	}

	return td.Execute(args)
}

// ============================================================
// 工具输入结构体
// ============================================================

type HTTPGetInput struct {
	URL     string            `json:"url" description:"请求的完整 URL 地址"`
	Headers map[string]string `json:"headers,omitempty" description:"请求头键值对，如 {\"User-Agent\": \"...\"}"`
}

type SkillInput struct {
	Name string `json:"name" description:"Skill 名称，如 msn-weather-api"`
}

type ReadFileInput struct {
	Path string `json:"path" description:"文件路径，相对于项目根目录"`
}

type TaskInput struct {
	Agent string         `json:"agent" description:"子 Agent 名称，如 weather"`
	Args  map[string]any `json:"args" description:"子 Agent 参数对象"`
}

type MemoryReadInput struct {
	Path string `json:"path" description:"文件路径。config/user.md(画像)、config/soul.md(AI灵魂)、session/dialog.yml(对话摘要)、notes/*.md(备忘录) 等。留空返回可用文件列表"`
}

type MemoryWriteInput struct {
	Path  string      `json:"path" description:"文件路径。.md 按 ## 标题合并（value 传字符串）；.yml 按 key 合并（value 传对象）"`
	Value interface{} `json:"value" description:"内容。格式取决于文件类型"`
}

type GeocodeInput struct {
	City string `json:"city" description:"城市名称，支持中文（如 北京）或英文（如 Beijing）"`
}

// ============================================================
// 工具注册
// ============================================================

// mdMerge 按 ## 标题合并 Markdown 文件。
// incoming 中的标题覆盖 existing 中同名的，其他段保留。
func mdMerge(existing, incoming string) string {
	if existing == "" {
		return incoming
	}
	if incoming == "" {
		return existing
	}

	type section struct {
		heading string
		content string
	}

	parse := func(text string) []section {
		var secs []section
		var cur section
		for _, line := range strings.Split(text, "\n") {
			if h, ok := strings.CutPrefix(line, "## "); ok && h != "" {
				if cur.heading != "" || cur.content != "" {
					secs = append(secs, cur)
				}
				cur = section{heading: h}
			} else {
				if cur.content != "" {
					cur.content += "\n"
				}
				cur.content += line
			}
		}
		if cur.heading != "" || cur.content != "" {
			secs = append(secs, cur)
		}
		return secs
	}

	existingSecs := parse(existing)
	incomingSecs := parse(incoming)

	headingIdx := make(map[string]int)
	for i, s := range existingSecs {
		headingIdx[s.heading] = i
	}

	seen := make(map[string]bool)
	var merged []section

	for _, s := range existingSecs {
		found := false
		for _, in := range incomingSecs {
			if in.heading == s.heading {
				merged = append(merged, in)
				seen[in.heading] = true
				found = true
				break
			}
		}
		if !found {
			merged = append(merged, s)
		}
	}

	for _, in := range incomingSecs {
		if !seen[in.heading] {
			merged = append(merged, in)
		}
	}

	var out strings.Builder
	for i, s := range merged {
		if i > 0 {
			out.WriteString("\n")
		}
		if s.heading != "" {
			out.WriteString("## ")
			out.WriteString(s.heading)
			out.WriteString("\n")
		}
		if strings.TrimSpace(s.content) != "" {
			out.WriteString(strings.TrimRight(s.content, "\n"))
			out.WriteString("\n")
		}
	}
	return out.String()
}

func init() {
	RegisterTool(NewTool[HTTPGetInput]("http-get",
		"发送 HTTP GET 请求获取数据",
		func(args HTTPGetInput) (string, error) {
			req, err := http.NewRequest("GET", args.URL, nil)
			if err != nil {
				return "", fmt.Errorf("创建请求失败: %w", err)
			}
			for k, v := range args.Headers {
				req.Header.Set(k, v)
			}

			client := &http.Client{Timeout: 15 * time.Second}
			resp, err := client.Do(req)
			if err != nil {
				return "", fmt.Errorf("请求失败: %w", err)
			}
			defer resp.Body.Close()

			body, err := io.ReadAll(resp.Body)
			if err != nil {
				return "", fmt.Errorf("读取响应失败: %w", err)
			}

			if resp.StatusCode != 200 {
				return fmt.Sprintf("HTTP %d: %s", resp.StatusCode, string(body)), nil
			}
			return string(body), nil
		},
	))

	RegisterTool(NewTool[SkillInput]("skill",
		"加载指定名称的 Skill 知识内容到当前上下文，获取专业知识",
		func(args SkillInput) (string, error) {
			return LoadSkill(args.Name)
		},
	))

	RegisterTool(NewTool[ReadFileInput]("read-file",
		"读取本地文件内容",
		func(args ReadFileInput) (string, error) {
			data, err := os.ReadFile(args.Path)
			if err != nil {
				return "", fmt.Errorf("读取文件失败: %w", err)
			}
			return string(data), nil
		},
	))

	RegisterTool(NewTool[TaskInput]("task",
		"调度子 Agent 执行领域任务。sub-agent 加载后自动查缓存，有缓存直接返回，无缓存调 LLM + 工具链获取新数据",
		func(args TaskInput) (string, error) {
			infoLog("task("+args.Agent+") 开始")
			registry := ScanAgents()
			sub := registry.GetSub(args.Agent)
			if sub == nil {
				errorLog("未找到子 Agent", "agent", args.Agent)
				return "", fmt.Errorf("未找到子 Agent: %s", args.Agent)
			}

			var cacheKey string
			var cacheData interface{}
			if sub.Cache != nil && len(sub.Cache.Keys) > 0 {
				cacheKey = buildCacheKey(sub.Cache.Keys, args.Args)
				if entry := readCache(args.Agent, cacheKey); entry != nil {
					cacheData = entry.Data
				}
			}

			subInput := map[string]any{
				"args":       args.Args,
				"cache_data": cacheData,
			}
			subInputBytes, _ := json.Marshal(subInput)

			result, err := RunSubAgent(sub, string(subInputBytes))
			if err != nil {
				errorLog("task("+args.Agent+") 失败", "err", err)
				return "", fmt.Errorf("子 Agent %s 执行失败: %w", args.Agent, err)
			}

			text, resultData := parseSubResult(result)

			if cacheKey != "" && resultData != nil && sub.Cache != nil {
				writeCache(args.Agent, cacheKey, resultData, args.Args, sub.Cache.TTL)
			}

			infoLog("task("+args.Agent+") 完成")
			return text, nil
		},
	))

	RegisterTool(NewTool[MemoryReadInput]("memory.read",
		"读取记忆文件。路径支持 config/, session/, log.yml, notes/ 等。返回文件原始内容",
		func(args MemoryReadInput) (string, error) {
			fullPath, err := safeMemoryPath(args.Path)
			if err != nil {
				return "", err
			}
			info, err := os.Stat(fullPath)
			if err != nil {
				if os.IsNotExist(err) {
					return "null", nil
				}
				return "", fmt.Errorf("读取失败: %w", err)
			}
			if info.IsDir() {
				entries, err := os.ReadDir(fullPath)
				if err != nil {
					return "", fmt.Errorf("读取目录失败: %w", err)
				}
				names := make([]string, 0)
				for _, e := range entries {
					if !e.IsDir() {
						names = append(names, e.Name())
					}
				}
				out, _ := yaml.Marshal(names)
				return string(out), nil
			}

			data, err := os.ReadFile(fullPath)
			if err != nil {
				return "", fmt.Errorf("读取失败: %w", err)
			}
			return string(data), nil
		},
	))

	RegisterTool(NewTool[MemoryWriteInput]("memory.write",
		"写入记忆文件。.md 按 ## 标题合并（value 传字符串），.yml 按 key 合并（value 传对象）。目录自动创建",
		func(args MemoryWriteInput) (string, error) {
			fullPath, err := safeMemoryPath(args.Path)
			if err != nil {
				return "", err
			}
			os.MkdirAll(filepath.Dir(fullPath), 0755)

			ext := filepath.Ext(args.Path)
			switch ext {
			case ".yaml", ".yml":
				existing := make(map[string]any)
				if data, err := os.ReadFile(fullPath); err == nil {
					if err := yaml.Unmarshal(data, &existing); err != nil {
						warnLog("解析 yml 失败", "path", args.Path, "err", err)
					}
				}
				if m, ok := args.Value.(map[string]any); ok {
					for k, v := range m {
						existing[k] = v
					}
				}
				out, err := yaml.Marshal(existing)
				if err != nil {
					return "", fmt.Errorf("序列化 yml 失败: %w", err)
				}
				if err := os.WriteFile(fullPath, out, 0644); err != nil {
					return "", fmt.Errorf("写入失败: %w", err)
				}
			default:
				str, ok := args.Value.(string)
				if !ok {
					return "", fmt.Errorf(".md 文件 value 必须是字符串")
				}
				existing := ""
				if data, err := os.ReadFile(fullPath); err == nil {
					existing = string(data)
				} else if !os.IsNotExist(err) {
					warnLog("读取 md 失败", "path", args.Path, "err", err)
				}
				merged := mdMerge(existing, str)
				if err := os.WriteFile(fullPath, []byte(merged), 0644); err != nil {
					return "", fmt.Errorf("写入失败: %w", err)
				}
			}
			return "ok", nil
		},
	))

	RegisterTool(NewTool[GeocodeInput]("geocode",
		"查询城市或地点的经纬度坐标，返回 lat/lon/name/country。支持中文城市名（如 北京、上海、成都）和英文名",
		func(args GeocodeInput) (string, error) {
			url := fmt.Sprintf("https://wttr.in/%s?format=j1", args.City)
			req, err := http.NewRequest("GET", url, nil)
			if err != nil {
				return "", fmt.Errorf("创建请求失败: %w", err)
			}

			client := &http.Client{Timeout: 15 * time.Second}
			resp, err := client.Do(req)
			if err != nil {
				return "", fmt.Errorf("请求 wttr.in 失败: %w", err)
			}
			defer resp.Body.Close()

			body, err := io.ReadAll(resp.Body)
			if err != nil {
				return "", fmt.Errorf("读取响应失败: %w", err)
			}

			if resp.StatusCode != 200 {
				return "", fmt.Errorf("wttr.in 返回 HTTP %d: %s", resp.StatusCode, string(body))
			}

			var result struct {
				NearestArea []struct {
					AreaName  []struct{ Value string `json:"value"` } `json:"areaName"`
					Country   []struct{ Value string `json:"value"` } `json:"country"`
					Latitude  string                                   `json:"latitude"`
					Longitude string                                   `json:"longitude"`
				} `json:"nearest_area"`
			}

			if err := json.Unmarshal(body, &result); err != nil {
				return "", fmt.Errorf("解析 wttr.in 响应失败: %w", err)
			}

			if len(result.NearestArea) == 0 {
				return "", fmt.Errorf("未找到城市: %s", args.City)
			}

			area := result.NearestArea[0]
			name := ""
			if len(area.AreaName) > 0 {
				name = area.AreaName[0].Value
			}
			country := ""
			if len(area.Country) > 0 {
				country = area.Country[0].Value
			}

			out, _ := json.Marshal(map[string]any{
				"lat":     area.Latitude,
				"lon":     area.Longitude,
				"name":    name,
				"country": country,
			})
			return string(out), nil
		},
	))
}