package api

import (
	"database/sql"
	"log"
	"net/http"

	"pinepods/gpodder-api/internal/db"
	"pinepods/gpodder-api/internal/models"

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

// getSyncStatus handles GET /api/2/sync-devices/{username}.json
func getSyncStatus(database *db.Database) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Get user ID from middleware
		userID, _ := c.Get("userID")

		// Query for device sync pairs
		var query string
		var rows *sql.Rows
		var err error

		if database.IsPostgreSQLDB() {
			query = `
				SELECT d1.DeviceName, d2.DeviceName
				FROM "GpodderSyncDevicePairs" p
				JOIN "GpodderDevices" d1 ON p.DeviceID1 = d1.DeviceID
				JOIN "GpodderDevices" d2 ON p.DeviceID2 = d2.DeviceID
				WHERE p.UserID = $1
			`
			rows, err = database.Query(query, userID)
		} else {
			query = `
				SELECT d1.DeviceName, d2.DeviceName
				FROM GpodderSyncDevicePairs p
				JOIN GpodderDevices d1 ON p.DeviceID1 = d1.DeviceID
				JOIN GpodderDevices d2 ON p.DeviceID2 = d2.DeviceID
				WHERE p.UserID = ?
			`
			rows, err = database.Query(query, userID)
		}

		if err != nil {
			log.Printf("Error querying device sync pairs: %v", err)
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get sync status"})
			return
		}

		// Build sync pairs
		syncPairs := make([][]string, 0)
		for rows.Next() {
			var device1, device2 string
			if err := rows.Scan(&device1, &device2); err != nil {
				log.Printf("Error scanning device pair: %v", err)
				continue
			}
			syncPairs = append(syncPairs, []string{device1, device2})
		}
		rows.Close()

		// Query for devices not in any sync pair
		if database.IsPostgreSQLDB() {
			query = `
				SELECT d.DeviceName
				FROM "GpodderDevices" d
				WHERE d.UserID = $1
				AND d.DeviceID NOT IN (
					SELECT DeviceID1 FROM "GpodderSyncDevicePairs" WHERE UserID = $1
					UNION
					SELECT DeviceID2 FROM "GpodderSyncDevicePairs" WHERE UserID = $1
				)
			`
			rows, err = database.Query(query, userID)
		} else {
			query = `
				SELECT d.DeviceName
				FROM GpodderDevices d
				WHERE d.UserID = ?
				AND d.DeviceID NOT IN (
					SELECT DeviceID1 FROM GpodderSyncDevicePairs WHERE UserID = ?
					UNION
					SELECT DeviceID2 FROM GpodderSyncDevicePairs WHERE UserID = ?
				)
			`
			rows, err = database.Query(query, userID, userID, userID)
		}

		if err != nil {
			log.Printf("Error querying non-synced devices: %v", err)
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get sync status"})
			return
		}

		// Build non-synced devices list
		nonSynced := make([]string, 0)
		for rows.Next() {
			var deviceName string
			if err := rows.Scan(&deviceName); err != nil {
				log.Printf("Error scanning non-synced device: %v", err)
				continue
			}
			nonSynced = append(nonSynced, deviceName)
		}
		rows.Close()

		// Return response
		c.JSON(http.StatusOK, models.SyncDevicesResponse{
			Synchronized:    syncPairs,
			NotSynchronized: nonSynced,
		})
	}
}

// updateSyncStatus handles POST /api/2/sync-devices/{username}.json
func updateSyncStatus(database *db.Database) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Get user ID from middleware
		userID, _ := c.Get("userID")

		// Parse request
		var req models.SyncDevicesRequest
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request body"})
			return
		}

		// Begin transaction
		tx, err := database.Begin()
		if err != nil {
			log.Printf("Error beginning transaction: %v", err)
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to begin transaction"})
			return
		}
		defer func() {
			if err != nil {
				tx.Rollback()
			}
		}()

		// Process synchronize pairs
		for _, pair := range req.Synchronize {
			if len(pair) != 2 {
				continue
			}

			// Get device IDs
			var device1ID, device2ID int
			var query string

			if database.IsPostgreSQLDB() {
				query = `
					SELECT DeviceID FROM "GpodderDevices"
					WHERE UserID = $1 AND DeviceName = $2
				`
				err = tx.QueryRow(query, userID, pair[0]).Scan(&device1ID)
			} else {
				query = `
					SELECT DeviceID FROM GpodderDevices
					WHERE UserID = ? AND DeviceName = ?
				`
				err = tx.QueryRow(query, userID, pair[0]).Scan(&device1ID)
			}

			if err != nil {
				log.Printf("Error getting device ID for %s: %v", pair[0], err)
				continue
			}

			if database.IsPostgreSQLDB() {
				err = tx.QueryRow(query, userID, pair[1]).Scan(&device2ID)
			} else {
				err = tx.QueryRow(query, userID, pair[1]).Scan(&device2ID)
			}

			if err != nil {
				log.Printf("Error getting device ID for %s: %v", pair[1], err)
				continue
			}

			// Ensure device1ID < device2ID for consistency
			if device1ID > device2ID {
				device1ID, device2ID = device2ID, device1ID
			}

			// Insert sync pair if it doesn't exist
			if database.IsPostgreSQLDB() {
				query = `
					INSERT INTO "GpodderSyncDevicePairs" (UserID, DeviceID1, DeviceID2)
					VALUES ($1, $2, $3)
					ON CONFLICT (UserID, DeviceID1, DeviceID2) DO NOTHING
				`
				_, err = tx.Exec(query, userID, device1ID, device2ID)
			} else {
				query = `
					INSERT IGNORE INTO GpodderSyncDevicePairs (UserID, DeviceID1, DeviceID2)
					VALUES (?, ?, ?)
				`
				_, err = tx.Exec(query, userID, device1ID, device2ID)
			}

			if err != nil {
				log.Printf("Error creating sync pair: %v", err)
				c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create sync pair"})
				return
			}
		}

		// Process stop-synchronize devices
		for _, deviceName := range req.StopSynchronize {
			// Get device ID
			var deviceID int
			var query string

			if database.IsPostgreSQLDB() {
				query = `
					SELECT DeviceID FROM "GpodderDevices"
					WHERE UserID = $1 AND DeviceName = $2
				`
				err = tx.QueryRow(query, userID, deviceName).Scan(&deviceID)
			} else {
				query = `
					SELECT DeviceID FROM GpodderDevices
					WHERE UserID = ? AND DeviceName = ?
				`
				err = tx.QueryRow(query, userID, deviceName).Scan(&deviceID)
			}

			if err != nil {
				log.Printf("Error getting device ID for %s: %v", deviceName, err)
				continue
			}

			// Remove all sync pairs involving this device
			if database.IsPostgreSQLDB() {
				query = `
					DELETE FROM "GpodderSyncDevicePairs"
					WHERE UserID = $1 AND (DeviceID1 = $2 OR DeviceID2 = $2)
				`
				_, err = tx.Exec(query, userID, deviceID)
			} else {
				query = `
					DELETE FROM GpodderSyncDevicePairs
					WHERE UserID = ? AND (DeviceID1 = ? OR DeviceID2 = ?)
				`
				_, err = tx.Exec(query, userID, deviceID, deviceID)
			}

			if err != nil {
				log.Printf("Error removing sync pairs: %v", err)
				c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to remove sync pairs"})
				return
			}
		}

		// Commit transaction
		if err = tx.Commit(); err != nil {
			log.Printf("Error committing transaction: %v", err)
			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to commit changes"})
			return
		}

		// Return updated sync status by reusing the getSyncStatus handler
		getSyncStatus(database)(c)
	}
}