package handlers

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"time"

	"github.com/HoHD/PR-Helper/services"
	"github.com/gin-gonic/gin"
)

type ReposHandler struct {
	db       *sql.DB
	reposDir string
}

func NewReposHandler(db *sql.DB, reposDir string) *ReposHandler {
	return &ReposHandler{db: db, reposDir: reposDir}
}

func (h *ReposHandler) ListRepos(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	rows, err := h.db.Query(`SELECT id, url, local_path, size_bytes, cloned_at, last_used FROM repositories WHERE user_id = ? ORDER BY last_used DESC`, user.ID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer rows.Close()
	var repos []gin.H
	for rows.Next() {
		var id int64
		var url, localPath string
		var sizeBytes int64
		var clonedAt, lastUsed string
		if rows.Scan(&id, &url, &localPath, &sizeBytes, &clonedAt, &lastUsed) == nil {
			repos = append(repos, gin.H{
				"id": id, "url": url, "local_path": localPath,
				"size_bytes": sizeBytes, "cloned_at": clonedAt, "last_used": lastUsed,
			})
		}
	}
	if err := rows.Err(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	if repos == nil {
		repos = []gin.H{}
	}
	c.JSON(http.StatusOK, repos)
}

func (h *ReposHandler) DeleteRepo(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	id := c.Param("id")
	var localPath string
	err := h.db.QueryRow(`SELECT local_path FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID).Scan(&localPath)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "仓库未找到"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	if err := os.RemoveAll(localPath); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "remove repo dir: " + err.Error()})
		return
	}
	if _, err := h.db.Exec(`DELETE FROM analyses WHERE repo_id = ? AND user_id = ?`, id, user.ID); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete analyses: " + err.Error()})
		return
	}
	if _, err := h.db.Exec(`DELETE FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete repository: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"ok": true})
}

func (h *ReposHandler) CleanupRepos(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	var maxAgeDays string
	h.db.QueryRow("SELECT value FROM user_settings WHERE user_id = ? AND `key` = 'cache.max_age_days'", user.ID).Scan(&maxAgeDays)
	if maxAgeDays == "" {
		maxAgeDays = "7"
	}
	rows, err := h.db.Query(`SELECT id, local_path FROM repositories WHERE user_id = ? AND last_used < DATE_SUB(NOW(), INTERVAL ? DAY)`, user.ID, maxAgeDays)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	defer rows.Close()
	var cleaned []int64
	var errs []string
	for rows.Next() {
		var id int64
		var localPath string
		if rows.Scan(&id, &localPath) == nil {
			if err := os.RemoveAll(localPath); err != nil {
				errs = append(errs, fmt.Sprintf("remove %d: %s", id, err.Error()))
				continue
			}
			if _, err := h.db.Exec(`DELETE FROM analyses WHERE repo_id = ? AND user_id = ?`, id, user.ID); err != nil {
				errs = append(errs, fmt.Sprintf("delete analyses %d: %s", id, err.Error()))
			}
			if _, err := h.db.Exec(`DELETE FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID); err != nil {
				errs = append(errs, fmt.Sprintf("delete repo %d: %s", id, err.Error()))
			}
			cleaned = append(cleaned, id)
		}
	}
	if err := rows.Err(); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	result := gin.H{"cleaned": cleaned}
	if len(errs) > 0 {
		result["errors"] = errs
	}
	c.JSON(http.StatusOK, result)
}

// PullRepo handles POST /api/repos/:id/pull — fetches and merges latest changes.
func (h *ReposHandler) PullRepo(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	id := c.Param("id")
	var localPath, authType string
	var credential sql.NullString
	err := h.db.QueryRow(`SELECT local_path, auth_type, credential FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID).Scan(&localPath, &authType, &credential)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "仓库未找到"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Parse stored credentials
	var username, password string
	if authType == "basic" && credential.Valid {
		var cred struct {
			Username string `json:"username"`
			Password string `json:"password"`
		}
		json.Unmarshal([]byte(credential.String), &cred)
		username = cred.Username
		password = cred.Password
	}

	result, err := services.PullRepo(localPath, username, password)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	h.db.Exec(`UPDATE repositories SET size_bytes = ?, last_used = NOW() WHERE id = ?`, result.SizeBytes, id)

	c.JSON(http.StatusOK, gin.H{
		"ok":       true,
		"repo_id":  id,
		"size_bytes": result.SizeBytes,
	})
}

// CloneRepo handles POST /api/repos with SSE progress events.
func (h *ReposHandler) CloneRepo(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	var req struct {
		URL      string `json:"url" binding:"required"`
		Username string `json:"username"`
		Password string `json:"password"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请输入仓库地址"})
		return
	}

	// Set SSE headers
	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")
	c.Header("X-Accel-Buffering", "no")
	c.Status(http.StatusOK)

	flusher, ok := c.Writer.(http.Flusher)
	if !ok {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "服务器不支持流式传输"})
		return
	}

	sendEvent := func(event string, data interface{}) {
		jsonData, err := json.Marshal(data)
		if err != nil {
			jsonData = []byte(`{"error":"序列化事件数据失败"}`)
		}
		fmt.Fprintf(c.Writer, "event: %s\ndata: %s\n\n", event, jsonData)
		flusher.Flush()
	}

	sendEvent("start", map[string]interface{}{"url": req.URL})

	// Generate unique directory name
	repoName := filepath.Base(req.URL)
	if repoName == "" || repoName == "." || repoName == "/" {
		repoName = fmt.Sprintf("repo_%d", time.Now().UnixNano())
	}
	repoDir := filepath.Join(h.reposDir, fmt.Sprintf("%s_%d", repoName, time.Now().UnixNano()))

	result, err := services.Clone(services.CloneOptions{
		URL:      req.URL,
		Dir:      repoDir,
		Username: req.Username,
		Password: req.Password,
	}, func(event string, data interface{}) {
		sendEvent(event, data)
	})

	if err != nil {
		sendEvent("error", map[string]interface{}{"message": err.Error()})
		return
	}

	// Determine auth type and credential for persistence
	authType := "none"
	var credential *string
	if req.Username != "" || req.Password != "" {
		authType = "basic"
		credJSON, _ := json.Marshal(map[string]string{
			"username": req.Username,
			"password": req.Password,
		})
		s := string(credJSON)
		credential = &s
	}

	// Save to database with user_id
	now := time.Now().Format("2006-01-02 15:04:05")
	res, err := h.db.Exec(`INSERT INTO repositories (user_id, url, local_path, size_bytes, cloned_at, last_used, auth_type, credential) VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
		user.ID, req.URL, repoDir, result.SizeBytes, now, now, authType, credential)
	if err != nil {
		sendEvent("error", map[string]interface{}{"message": "save to db: " + err.Error()})
		return
	}
	repoID, err := res.LastInsertId()
	if err != nil {
		sendEvent("error", map[string]interface{}{"message": "get repo id: " + err.Error()})
		return
	}

	sendEvent("complete", map[string]interface{}{
		"repo_id":    repoID,
		"size_bytes": result.SizeBytes,
	})
}

// GetGraph handles GET /api/repos/:id/graph — returns D3.js-compatible data.
func (h *ReposHandler) GetGraph(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	id := c.Param("id")
	var localPath string
	err := h.db.QueryRow(`SELECT local_path FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID).Scan(&localPath)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "仓库未找到"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Update last_used
	h.db.Exec(`UPDATE repositories SET last_used = NOW() WHERE id = ?`, id)

	repo, err := services.OpenRepo(localPath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "打开仓库失败: " + err.Error()})
		return
	}

	maxCommits := 200
	if mc := c.Query("max_commits"); mc != "" {
		if n, err := strconv.Atoi(mc); err == nil && n > 0 {
			maxCommits = n
		}
	}

	graph, err := services.GetGraph(repo, maxCommits)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, graph)
}

// GetDiff handles GET /api/repos/:id/diff — returns unified diff or per-file diffs.
func (h *ReposHandler) GetDiff(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	id := c.Param("id")
	base := c.Query("base")
	head := c.Query("head")

	if base == "" || head == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请选择 Base 和 Head 分支"})
		return
	}

	var localPath string
	err := h.db.QueryRow(`SELECT local_path FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID).Scan(&localPath)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "仓库未找到"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Update last_used
	h.db.Exec(`UPDATE repositories SET last_used = NOW() WHERE id = ?`, id)

	repo, err := services.OpenRepo(localPath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Check if per-file mode is requested
	if c.Query("per_file") == "true" {
		files, err := services.GetDiffFiles(repo, base, head)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, files)
		return
	}

	diff, err := services.GetDiff(repo, base, head)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"diff": diff})
}

// GetRefs handles GET /api/repos/:id/refs — returns branches and tags.
func (h *ReposHandler) GetRefs(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	id := c.Param("id")
	var localPath string
	err := h.db.QueryRow(`SELECT local_path FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID).Scan(&localPath)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "仓库未找到"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	repo, err := services.OpenRepo(localPath)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	refs, err := services.GetRefs(repo)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, refs)
}

// GetCommits handles GET /api/repos/:id/commits — returns commit log for a ref.
func (h *ReposHandler) GetCommits(c *gin.Context) {
	user := GetCurrentUser(c)
	if user == nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "未登录"})
		return
	}

	id := c.Param("id")
	refName := c.Query("ref")
	if refName == "" {
		refName = "HEAD"
	}
	maxCommits := 100
	if mc := c.Query("limit"); mc != "" {
		if n, err := strconv.Atoi(mc); err == nil && n > 0 {
			maxCommits = n
		}
	}

	var localPath string
	err := h.db.QueryRow(`SELECT local_path FROM repositories WHERE id = ? AND user_id = ?`, id, user.ID).Scan(&localPath)
	if err == sql.ErrNoRows {
		c.JSON(http.StatusNotFound, gin.H{"error": "仓库未找到"})
		return
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	commits, err := services.GetBranchCommits(localPath, refName, maxCommits)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, commits)
}

func dirSize(path string) int64 {
	var size int64
	filepath.Walk(path, func(_ string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() {
			return nil
		}
		size += info.Size()
		return nil
	})
	return size
}