package handlers

import (
	"html/template"
	"log/slog"
	"net/http"
	"path/filepath"
	"time"

	"github.com/gin-gonic/gin"
	"git.mchus.pro/mchus/quoteforge/internal/localdb"
	"git.mchus.pro/mchus/quoteforge/internal/services/sync"
	"gorm.io/gorm"
)

// SyncHandler handles sync API endpoints
type SyncHandler struct {
	localDB     *localdb.LocalDB
	syncService *sync.Service
	mariaDB     *gorm.DB
	tmpl        *template.Template
}

// NewSyncHandler creates a new sync handler
func NewSyncHandler(localDB *localdb.LocalDB, syncService *sync.Service, mariaDB *gorm.DB, templatesPath string) (*SyncHandler, error) {
	// Load sync_status partial template
	partialPath := filepath.Join(templatesPath, "partials", "sync_status.html")
	tmpl, err := template.ParseFiles(partialPath)
	if err != nil {
		return nil, err
	}

	return &SyncHandler{
		localDB:     localDB,
		syncService: syncService,
		mariaDB:     mariaDB,
		tmpl:        tmpl,
	}, nil
}

// SyncStatusResponse represents the sync status
type SyncStatusResponse struct {
	LastComponentSync  *time.Time `json:"last_component_sync"`
	LastPricelistSync  *time.Time `json:"last_pricelist_sync"`
	IsOnline           bool       `json:"is_online"`
	ComponentsCount    int64      `json:"components_count"`
	PricelistsCount    int64      `json:"pricelists_count"`
	ServerPricelists   int        `json:"server_pricelists"`
	NeedComponentSync  bool       `json:"need_component_sync"`
	NeedPricelistSync  bool       `json:"need_pricelist_sync"`
}

// GetStatus returns current sync status
// GET /api/sync/status
func (h *SyncHandler) GetStatus(c *gin.Context) {
	// Check online status by pinging MariaDB
	isOnline := h.checkOnline()

	// Get sync times
	lastComponentSync := h.localDB.GetComponentSyncTime()
	lastPricelistSync := h.localDB.GetLastSyncTime()

	// Get counts
	componentsCount := h.localDB.CountLocalComponents()
	pricelistsCount := h.localDB.CountLocalPricelists()

	// Get server pricelist count if online
	serverPricelists := 0
	needPricelistSync := false
	if isOnline {
		status, err := h.syncService.GetStatus()
		if err == nil {
			serverPricelists = status.ServerPricelists
			needPricelistSync = status.NeedsSync
		}
	}

	// Check if component sync is needed (older than 24 hours)
	needComponentSync := h.localDB.NeedComponentSync(24)

	c.JSON(http.StatusOK, SyncStatusResponse{
		LastComponentSync:  lastComponentSync,
		LastPricelistSync:  lastPricelistSync,
		IsOnline:           isOnline,
		ComponentsCount:    componentsCount,
		PricelistsCount:    pricelistsCount,
		ServerPricelists:   serverPricelists,
		NeedComponentSync:  needComponentSync,
		NeedPricelistSync:  needPricelistSync,
	})
}

// SyncResultResponse represents sync operation result
type SyncResultResponse struct {
	Success  bool   `json:"success"`
	Message  string `json:"message"`
	Synced   int    `json:"synced"`
	Duration string `json:"duration"`
}

// SyncComponents syncs components from MariaDB to local SQLite
// POST /api/sync/components
func (h *SyncHandler) SyncComponents(c *gin.Context) {
	if !h.checkOnline() {
		c.JSON(http.StatusServiceUnavailable, gin.H{
			"success": false,
			"error":   "Database is offline",
		})
		return
	}

	result, err := h.localDB.SyncComponents(h.mariaDB)
	if err != nil {
		slog.Error("component sync failed", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"error":   err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, SyncResultResponse{
		Success:  true,
		Message:  "Components synced successfully",
		Synced:   result.TotalSynced,
		Duration: result.Duration.String(),
	})
}

// SyncPricelists syncs pricelists from MariaDB to local SQLite
// POST /api/sync/pricelists
func (h *SyncHandler) SyncPricelists(c *gin.Context) {
	if !h.checkOnline() {
		c.JSON(http.StatusServiceUnavailable, gin.H{
			"success": false,
			"error":   "Database is offline",
		})
		return
	}

	startTime := time.Now()
	synced, err := h.syncService.SyncPricelists()
	if err != nil {
		slog.Error("pricelist sync failed", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"error":   err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, SyncResultResponse{
		Success:  true,
		Message:  "Pricelists synced successfully",
		Synced:   synced,
		Duration: time.Since(startTime).String(),
	})
}

// SyncAllResponse represents result of full sync
type SyncAllResponse struct {
	Success            bool   `json:"success"`
	Message            string `json:"message"`
	ComponentsSynced   int    `json:"components_synced"`
	PricelistsSynced   int    `json:"pricelists_synced"`
	Duration           string `json:"duration"`
}

// SyncAll syncs both components and pricelists
// POST /api/sync/all
func (h *SyncHandler) SyncAll(c *gin.Context) {
	if !h.checkOnline() {
		c.JSON(http.StatusServiceUnavailable, gin.H{
			"success": false,
			"error":   "Database is offline",
		})
		return
	}

	startTime := time.Now()
	var componentsSynced, pricelistsSynced int

	// Sync components
	compResult, err := h.localDB.SyncComponents(h.mariaDB)
	if err != nil {
		slog.Error("component sync failed during full sync", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"error":   "Component sync failed: " + err.Error(),
		})
		return
	}
	componentsSynced = compResult.TotalSynced

	// Sync pricelists
	pricelistsSynced, err = h.syncService.SyncPricelists()
	if err != nil {
		slog.Error("pricelist sync failed during full sync", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{
			"success":          false,
			"error":            "Pricelist sync failed: " + err.Error(),
			"components_synced": componentsSynced,
		})
		return
	}

	c.JSON(http.StatusOK, SyncAllResponse{
		Success:          true,
		Message:          "Full sync completed successfully",
		ComponentsSynced: componentsSynced,
		PricelistsSynced: pricelistsSynced,
		Duration:         time.Since(startTime).String(),
	})
}

// checkOnline checks if MariaDB is accessible
func (h *SyncHandler) checkOnline() bool {
	sqlDB, err := h.mariaDB.DB()
	if err != nil {
		return false
	}

	if err := sqlDB.Ping(); err != nil {
		return false
	}

	return true
}

// PushPendingChanges pushes all pending changes to the server
// POST /api/sync/push
func (h *SyncHandler) PushPendingChanges(c *gin.Context) {
	if !h.checkOnline() {
		c.JSON(http.StatusServiceUnavailable, gin.H{
			"success": false,
			"error":   "Database is offline",
		})
		return
	}

	startTime := time.Now()
	pushed, err := h.syncService.PushPendingChanges()
	if err != nil {
		slog.Error("push pending changes failed", "error", err)
		c.JSON(http.StatusInternalServerError, gin.H{
			"success": false,
			"error":   err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, SyncResultResponse{
		Success:  true,
		Message:  "Pending changes pushed successfully",
		Synced:   pushed,
		Duration: time.Since(startTime).String(),
	})
}

// GetPendingCount returns the number of pending changes
// GET /api/sync/pending/count
func (h *SyncHandler) GetPendingCount(c *gin.Context) {
	count := h.localDB.GetPendingCount()
	c.JSON(http.StatusOK, gin.H{
		"count": count,
	})
}

// GetPendingChanges returns all pending changes
// GET /api/sync/pending
func (h *SyncHandler) GetPendingChanges(c *gin.Context) {
	changes, err := h.localDB.GetPendingChanges()
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"error": err.Error(),
		})
		return
	}

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

// SyncStatusPartial renders the sync status partial for htmx
// GET /partials/sync-status
func (h *SyncHandler) SyncStatusPartial(c *gin.Context) {
	// Check online status from middleware
	isOfflineValue, exists := c.Get("is_offline")
	isOffline := false
	if exists {
		isOffline = isOfflineValue.(bool)
	} else {
		// Fallback: check directly if middleware didn't set it
		isOffline = !h.checkOnline()
		slog.Warn("is_offline not found in context, checking directly")
	}

	// Get pending count
	pendingCount := h.localDB.GetPendingCount()

	slog.Debug("rendering sync status", "is_offline", isOffline, "pending_count", pendingCount)

	data := gin.H{
		"IsOffline":    isOffline,
		"PendingCount": pendingCount,
	}

	c.Header("Content-Type", "text/html; charset=utf-8")
	if err := h.tmpl.ExecuteTemplate(c.Writer, "sync_status", data); err != nil {
		slog.Error("failed to render sync_status template", "error", err)
		c.String(http.StatusInternalServerError, "Template error: "+err.Error())
	}
}