package handler

import (
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strings"

	"cyberstrike-ai/internal/agents"
	"cyberstrike-ai/internal/config"

	"github.com/gin-gonic/gin"
)

var markdownAgentFilenameRe = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9_.-]*\.md$`)

// MarkdownAgentsHandler 管理 agents 目录下子代理 Markdown（增删改查）。
type MarkdownAgentsHandler struct {
	dir string
}

// NewMarkdownAgentsHandler dir 须为已解析的绝对路径。
func NewMarkdownAgentsHandler(dir string) *MarkdownAgentsHandler {
	return &MarkdownAgentsHandler{dir: strings.TrimSpace(dir)}
}

func (h *MarkdownAgentsHandler) safeJoin(filename string) (string, error) {
	filename = strings.TrimSpace(filename)
	if filename == "" || !markdownAgentFilenameRe.MatchString(filename) {
		return "", fmt.Errorf("非法文件名")
	}
	clean := filepath.Clean(filename)
	if clean != filename || strings.Contains(clean, "..") {
		return "", fmt.Errorf("非法文件名")
	}
	return filepath.Join(h.dir, clean), nil
}

// existingOtherOrchestrator 若目录中已有别的主代理文件，返回其文件名；writingBasename 为当前正在写入的文件名时视为同一文件不冲突。
func existingOtherOrchestrator(dir, writingBasename string) (other string, err error) {
	load, err := agents.LoadMarkdownAgentsDir(dir)
	if err != nil {
		return "", err
	}
	if load.Orchestrator == nil {
		return "", nil
	}
	if strings.EqualFold(load.Orchestrator.Filename, writingBasename) {
		return "", nil
	}
	return load.Orchestrator.Filename, nil
}

// ListMarkdownAgents GET /api/multi-agent/markdown-agents
func (h *MarkdownAgentsHandler) ListMarkdownAgents(c *gin.Context) {
	if h.dir == "" {
		c.JSON(http.StatusOK, gin.H{"agents": []any{}, "dir": "", "error": "未配置 agents 目录"})
		return
	}
	files, err := agents.LoadMarkdownAgentFiles(h.dir)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	out := make([]gin.H, 0, len(files))
	for _, fa := range files {
		sub := fa.Config
		out = append(out, gin.H{
			"filename":        fa.Filename,
			"id":              sub.ID,
			"name":            sub.Name,
			"description":     sub.Description,
			"is_orchestrator": fa.IsOrchestrator,
			"kind":            sub.Kind,
		})
	}
	c.JSON(http.StatusOK, gin.H{"agents": out, "dir": h.dir})
}

// GetMarkdownAgent GET /api/multi-agent/markdown-agents/:filename
func (h *MarkdownAgentsHandler) GetMarkdownAgent(c *gin.Context) {
	filename := c.Param("filename")
	path, err := h.safeJoin(filename)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	b, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			c.JSON(http.StatusNotFound, gin.H{"error": "文件不存在"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	sub, err := agents.ParseMarkdownSubAgent(filename, string(b))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	isOrch := agents.IsOrchestratorMarkdown(filename, agents.FrontMatter{Kind: sub.Kind})
	c.JSON(http.StatusOK, gin.H{
		"filename":        filename,
		"raw":             string(b),
		"id":              sub.ID,
		"name":            sub.Name,
		"description":     sub.Description,
		"tools":           sub.RoleTools,
		"instruction":     sub.Instruction,
		"bind_role":       sub.BindRole,
		"max_iterations":  sub.MaxIterations,
		"kind":            sub.Kind,
		"is_orchestrator": isOrch,
	})
}

type markdownAgentBody struct {
	Filename       string   `json:"filename"`
	ID             string   `json:"id"`
	Name           string   `json:"name"`
	Description    string   `json:"description"`
	Tools          []string `json:"tools"`
	Instruction    string   `json:"instruction"`
	BindRole       string   `json:"bind_role"`
	MaxIterations  int      `json:"max_iterations"`
	Kind           string   `json:"kind"`
	Raw            string   `json:"raw"`
}

// CreateMarkdownAgent POST /api/multi-agent/markdown-agents
func (h *MarkdownAgentsHandler) CreateMarkdownAgent(c *gin.Context) {
	if h.dir == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "未配置 agents 目录"})
		return
	}
	var body markdownAgentBody
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	filename := strings.TrimSpace(body.Filename)
	if filename == "" {
		if strings.EqualFold(strings.TrimSpace(body.Kind), "orchestrator") {
			filename = agents.OrchestratorMarkdownFilename
		} else {
			base := agents.SlugID(body.Name)
			if base == "" {
				base = "agent"
			}
			filename = base + ".md"
		}
	}
	path, err := h.safeJoin(filename)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if _, err := os.Stat(path); err == nil {
		c.JSON(http.StatusConflict, gin.H{"error": "文件已存在"})
		return
	}
	sub := config.MultiAgentSubConfig{
		ID:            strings.TrimSpace(body.ID),
		Name:          strings.TrimSpace(body.Name),
		Description:   strings.TrimSpace(body.Description),
		Instruction:   strings.TrimSpace(body.Instruction),
		RoleTools:     body.Tools,
		BindRole:      strings.TrimSpace(body.BindRole),
		MaxIterations: body.MaxIterations,
		Kind:          strings.TrimSpace(body.Kind),
	}
	if strings.EqualFold(filepath.Base(path), agents.OrchestratorMarkdownFilename) && sub.Kind == "" {
		sub.Kind = "orchestrator"
	}
	if sub.ID == "" {
		sub.ID = agents.SlugID(sub.Name)
	}
	if sub.Name == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "name 必填"})
		return
	}
	var out []byte
	if strings.TrimSpace(body.Raw) != "" {
		out = []byte(body.Raw)
	} else {
		out, err = agents.BuildMarkdownFile(sub)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
	}
	if want := agents.WantsMarkdownOrchestrator(filepath.Base(path), body.Kind, string(out)); want {
		other, oerr := existingOtherOrchestrator(h.dir, filepath.Base(path))
		if oerr != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": oerr.Error()})
			return
		}
		if other != "" {
			c.JSON(http.StatusConflict, gin.H{"error": fmt.Sprintf("已存在主代理定义：%s，请先删除或取消其主代理标记", other)})
			return
		}
	}
	if err := os.MkdirAll(h.dir, 0755); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	if err := os.WriteFile(path, out, 0644); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"filename": filepath.Base(path), "message": "已创建"})
}

// UpdateMarkdownAgent PUT /api/multi-agent/markdown-agents/:filename
func (h *MarkdownAgentsHandler) UpdateMarkdownAgent(c *gin.Context) {
	filename := c.Param("filename")
	path, err := h.safeJoin(filename)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	var body markdownAgentBody
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	sub := config.MultiAgentSubConfig{
		ID:            strings.TrimSpace(body.ID),
		Name:          strings.TrimSpace(body.Name),
		Description:   strings.TrimSpace(body.Description),
		Instruction:   strings.TrimSpace(body.Instruction),
		RoleTools:     body.Tools,
		BindRole:      strings.TrimSpace(body.BindRole),
		MaxIterations: body.MaxIterations,
		Kind:          strings.TrimSpace(body.Kind),
	}
	if strings.EqualFold(filename, agents.OrchestratorMarkdownFilename) && sub.Kind == "" {
		sub.Kind = "orchestrator"
	}
	if sub.Name == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "name 必填"})
		return
	}
	if sub.ID == "" {
		sub.ID = agents.SlugID(sub.Name)
	}
	var out []byte
	if strings.TrimSpace(body.Raw) != "" {
		out = []byte(body.Raw)
	} else {
		out, err = agents.BuildMarkdownFile(sub)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
	}
	if want := agents.WantsMarkdownOrchestrator(filename, body.Kind, string(out)); want {
		other, oerr := existingOtherOrchestrator(h.dir, filename)
		if oerr != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": oerr.Error()})
			return
		}
		if other != "" {
			c.JSON(http.StatusConflict, gin.H{"error": fmt.Sprintf("已存在主代理定义：%s，请先删除或取消其主代理标记", other)})
			return
		}
	}
	if err := os.WriteFile(path, out, 0644); err != nil {
		if os.IsNotExist(err) {
			c.JSON(http.StatusNotFound, gin.H{"error": "文件不存在"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "已保存"})
}

// DeleteMarkdownAgent DELETE /api/multi-agent/markdown-agents/:filename
func (h *MarkdownAgentsHandler) DeleteMarkdownAgent(c *gin.Context) {
	filename := c.Param("filename")
	path, err := h.safeJoin(filename)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if err := os.Remove(path); err != nil {
		if os.IsNotExist(err) {
			c.JSON(http.StatusNotFound, gin.H{"error": "文件不存在"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "已删除"})
}