// Package api provides HTTP API handlers
package api

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"time"

	"spiderman/internal/fabric"
	"spiderman/internal/logger"
	"spiderman/pkg/models"

	"github.com/google/uuid"
	"github.com/gorilla/mux"
	"github.com/sirupsen/logrus"
)

// Handler handles HTTP requests and communicates with Fabric
type Handler struct {
	fabricClient *fabric.Client
}

// NewHandler creates a new API handler
func NewHandler(fabricClient *fabric.Client) *Handler {
	logger.Logger.Info("API handler initialized")
	return &Handler{
		fabricClient: fabricClient,
	}
}

// writeJSONResponse writes a JSON response to the HTTP response writer
func writeJSONResponse(w http.ResponseWriter, statusCode int, response models.Response) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(statusCode)
	json.NewEncoder(w).Encode(response)
}

// writeErrorResponse writes an error response to the HTTP response writer
func writeErrorResponse(w http.ResponseWriter, statusCode int, message string) {
	writeJSONResponse(w, statusCode, models.Response{
		Success: false,
		Message: message,
	})
}

// HealthCheck godoc
//
//	@Summary		Health check
//	@Description	Check the health status of the API
//	@Tags			health
//	@Accept			json
//	@Produce		json
//	@Success		200	{object}	models.HealthResponse
//	@Router			/health [get]
func (h *Handler) HealthCheck(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	requestLogger.Debug("Processing health check request")

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(models.HealthResponse{Status: "healthy"})

	requestLogger.Info("Health check completed successfully")
}

// InitLedger godoc
//
//	@Summary		Initialize ledger
//	@Description	Initialize the blockchain ledger with a set of assets
//	@Tags			ledger
//	@Accept			json
//	@Produce		json
//	@Success		200	{object}	models.Response
//	@Failure		500	{object}	models.ErrorResponse
//	@Router			/ledger/init [post]
func (h *Handler) InitLedger(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	requestLogger.Info("Starting ledger initialization")

	start := time.Now()
	err := h.fabricClient.InitLedger()
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to initialize ledger")

		writeErrorResponse(w, http.StatusInternalServerError,
			fmt.Sprintf("Failed to initialize ledger: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"duration_ms": duration.Milliseconds(),
	}).Info("Ledger initialized successfully")

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Message: "Ledger initialized successfully",
	})
}

// GetAllAssets godoc
//
//	@Summary		Get all assets
//	@Description	Retrieve all assets from the blockchain ledger
//	@Tags			assets
//	@Accept			json
//	@Produce		json
//	@Success		200	{object}	models.Response{data=[]models.Asset}
//	@Failure		500	{object}	models.ErrorResponse
//	@Router			/assets [get]
func (h *Handler) GetAllAssets(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	requestLogger.Info("Retrieving all assets")

	start := time.Now()
	assets, err := h.fabricClient.GetAllAssets()
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to retrieve assets")

		writeErrorResponse(w, http.StatusInternalServerError,
			fmt.Sprintf("Failed to get assets: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"asset_count": len(assets),
		"duration_ms": duration.Milliseconds(),
	}).Info("Assets retrieved successfully")

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Data:    assets,
	})
}

// CreateAsset godoc
//
//	@Summary		Create a new asset
//	@Description	Create a new asset on the blockchain ledger with auto-generated UUID if ID not provided
//	@Tags			assets
//	@Accept			json
//	@Produce		json
//	@Param			asset	body		models.CreateAssetRequest	true	"Asset data (ID is optional and will be auto-generated)"
//	@Success		201		{object}	models.Response{data=object{asset=models.Asset,transactionId=string}}
//	@Failure		400		{object}	models.ErrorResponse
//	@Failure		500		{object}	models.ErrorResponse
//	@Router			/assets [post]
func (h *Handler) CreateAsset(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	requestLogger.Info("Creating new asset")

	var req models.CreateAssetRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		requestLogger.WithError(err).Warn("Invalid request body for asset creation")
		writeErrorResponse(w, http.StatusBadRequest, "Invalid request body")
		return
	}

	// Auto-generate UUID if ID is not provided
	if req.ID == "" {
		req.ID = uuid.New().String()
		requestLogger.WithField("generated_id", req.ID).Info("Auto-generated UUID for asset")
	}

	requestLogger.WithFields(logrus.Fields{
		"asset_id": req.ID,
		"owner":    req.Owner,
		"color":    req.Color,
		"size":     req.Size,
		"value":    req.AppraisedValue,
	}).Debug("Asset creation request details")

	// Convert request to asset model
	asset := models.Asset{
		ID:             req.ID,
		Color:          req.Color,
		Size:           req.Size,
		Owner:          req.Owner,
		AppraisedValue: req.AppraisedValue,
	}

	start := time.Now()
	transactionResult, err := h.fabricClient.CreateAsset(asset)
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"asset_id":    req.ID,
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to create asset")

		writeErrorResponse(w, http.StatusInternalServerError,
			fmt.Sprintf("Failed to create asset: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"asset_id":           req.ID,
		"transaction_result": transactionResult,
		"duration_ms":        duration.Milliseconds(),
	}).Info("Asset created successfully")

	// Create response data that includes both asset and transaction ID
	responseData := map[string]interface{}{
		"asset":         asset,
		"transactionId": transactionResult,
	}

	writeJSONResponse(w, http.StatusCreated, models.Response{
		Success: true,
		Message: "Asset created successfully",
		Data:    responseData,
	})
}

// GetAssetByID godoc
//
//	@Summary		Get asset by ID
//	@Description	Retrieve a specific asset by its ID from the blockchain ledger
//	@Tags			assets
//	@Accept			json
//	@Produce		json
//	@Param			id	path		string	true	"Asset ID"
//	@Success		200	{object}	models.Response{data=models.Asset}
//	@Failure		404	{object}	models.ErrorResponse
//	@Failure		500	{object}	models.ErrorResponse
//	@Router			/assets/{id} [get]
func (h *Handler) GetAssetByID(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	vars := mux.Vars(r)
	assetID := vars["id"]

	requestLogger.WithField("asset_id", assetID).Info("Retrieving asset by ID")

	start := time.Now()
	asset, err := h.fabricClient.ReadAssetByID(assetID)
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"asset_id":    assetID,
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to retrieve asset")

		statusCode := http.StatusInternalServerError
		if err.Error() == "asset not found" {
			statusCode = http.StatusNotFound
		}

		writeErrorResponse(w, statusCode,
			fmt.Sprintf("Failed to get asset: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"asset_id":    assetID,
		"duration_ms": duration.Milliseconds(),
	}).Info("Asset retrieved successfully")

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Data:    asset,
	})
}

// TransferAsset godoc
//
//	@Summary		Transfer asset ownership
//	@Description	Transfer ownership of an asset to a new owner
//	@Tags			assets
//	@Accept			json
//	@Produce		json
//	@Param			id		path		string					true	"Asset ID"
//	@Param			request	body		models.TransferAssetRequest	true	"Transfer request"
//	@Success		200		{object}	models.Response
//	@Failure		400		{object}	models.ErrorResponse
//	@Failure		404		{object}	models.ErrorResponse
//	@Failure		500		{object}	models.ErrorResponse
//	@Router			/assets/{id}/transfer [put]
func (h *Handler) TransferAsset(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	vars := mux.Vars(r)
	assetID := vars["id"]

	requestLogger.WithField("asset_id", assetID).Info("Transferring asset")

	var req models.TransferAssetRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		requestLogger.WithError(err).Warn("Invalid request body for asset transfer")
		writeErrorResponse(w, http.StatusBadRequest, "Invalid request body")
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"asset_id":  assetID,
		"new_owner": req.NewOwner,
	}).Debug("Asset transfer request details")

	start := time.Now()
	err := h.fabricClient.TransferAsset(assetID, req.NewOwner)
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"asset_id":    assetID,
			"new_owner":   req.NewOwner,
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to transfer asset")

		statusCode := http.StatusInternalServerError
		if err.Error() == "asset not found" {
			statusCode = http.StatusNotFound
		}

		writeErrorResponse(w, statusCode,
			fmt.Sprintf("Failed to transfer asset: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"asset_id":    assetID,
		"new_owner":   req.NewOwner,
		"duration_ms": duration.Milliseconds(),
	}).Info("Asset transferred successfully")

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Message: "Asset transferred successfully",
	})
}

// UpdateAsset godoc
//
//	@Summary		Update an existing asset
//	@Description	Update an existing asset's information on the blockchain
//	@Tags			assets
//	@Accept			json
//	@Produce		json
//	@Param			id		path		string					true	"Asset ID"
//	@Param			asset	body		models.CreateAssetRequest	true	"Updated asset data"
//	@Success		200		{object}	models.Response{data=models.Asset}
//	@Failure		400		{object}	models.ErrorResponse
//	@Failure		500		{object}	models.ErrorResponse
//	@Router			/assets/{id} [put]
func (h *Handler) UpdateAsset(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	assetID := vars["id"]

	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr).
		WithField("asset_id", assetID)
	requestLogger.Info("Updating asset")

	var req models.CreateAssetRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		requestLogger.WithError(err).Warn("Invalid request body for asset update")
		writeErrorResponse(w, http.StatusBadRequest, "Invalid request body")
		return
	}

	// Set the ID from the URL
	req.ID = assetID

	requestLogger.WithFields(logrus.Fields{
		"owner": req.Owner,
		"color": req.Color,
		"size":  req.Size,
		"value": req.AppraisedValue,
	}).Debug("Asset update request details")

	// Convert request to asset model
	asset := models.Asset{
		ID:             req.ID,
		Color:          req.Color,
		Size:           req.Size,
		Owner:          req.Owner,
		AppraisedValue: req.AppraisedValue,
	}

	start := time.Now()
	err := h.fabricClient.UpdateAsset(asset)
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to update asset")

		writeErrorResponse(w, http.StatusInternalServerError,
			fmt.Sprintf("Failed to update asset: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"duration_ms": duration.Milliseconds(),
	}).Info("Asset updated successfully")

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Message: "Asset updated successfully",
		Data:    asset,
	})
}

// GetBlockHeight godoc
//
//	@Summary		Get block height
//	@Description	Get the current block height of the blockchain
//	@Tags			blockchain
//	@Accept			json
//	@Produce		json
//	@Success		200	{object}	models.Response{data=models.BlockHeightResponse}
//	@Failure		500	{object}	models.ErrorResponse
//	@Router			/blockchain/height [get]
func (h *Handler) GetBlockHeight(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	requestLogger.Info("Getting block height")

	start := time.Now()
	height, err := h.fabricClient.GetBlockHeight()
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to get block height")

		writeErrorResponse(w, http.StatusInternalServerError,
			fmt.Sprintf("Failed to get block height: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"height":      height,
		"duration_ms": duration.Milliseconds(),
	}).Info("Block height retrieved successfully")

	response := models.BlockHeightResponse{
		Height: height,
	}

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Message: "Block height retrieved successfully",
		Data:    response,
	})
}

// GetChainInfo godoc
//
//	@Summary		Get chain information
//	@Description	Get detailed information about the blockchain including block height
//	@Tags			blockchain
//	@Accept			json
//	@Produce		json
//	@Success		200	{object}	models.Response{data=models.ChainInfoResponse}
//	@Failure		500	{object}	models.ErrorResponse
//	@Router			/blockchain/info [get]
func (h *Handler) GetChainInfo(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	requestLogger.Info("Getting chain information")

	start := time.Now()
	height, err := h.fabricClient.GetBlockHeight()
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":       err.Error(),
			"duration_ms": duration.Milliseconds(),
		}).Error("Failed to get chain information")

		writeErrorResponse(w, http.StatusInternalServerError,
			fmt.Sprintf("Failed to get chain information: %s", fabric.HandleFabricError(err)))
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"height":      height,
		"duration_ms": duration.Milliseconds(),
	}).Info("Chain information retrieved successfully")

	response := models.ChainInfoResponse{
		Height:    height,
		ChainName: h.fabricClient.GetChannelName(),
	}

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Message: "Chain information retrieved successfully",
		Data:    response,
	})
}

// GetTransactionByID godoc
//
//	@Summary		Get transaction details by ID
//	@Description	Retrieve detailed information about a specific transaction by its ID
//	@Tags			transactions
//	@Accept			json
//	@Produce		json
//	@Param			txid	path		string	true	"Transaction ID"
//	@Success		200		{object}	models.Response{data=models.TransactionDetail}
//	@Failure		400		{object}	models.ErrorResponse
//	@Failure		404		{object}	models.ErrorResponse
//	@Failure		500		{object}	models.ErrorResponse
//	@Router			/transactions/{txid} [get]
func (h *Handler) GetTransactionByID(w http.ResponseWriter, r *http.Request) {
	requestLogger := logger.GetRequestLogger(r.Method, r.URL.Path, r.RemoteAddr)
	vars := mux.Vars(r)
	txID := vars["txid"]

	if txID == "" {
		requestLogger.Warn("Missing transaction ID in request")
		writeErrorResponse(w, http.StatusBadRequest, "Transaction ID is required")
		return
	}

	requestLogger.WithField("transaction_id", txID).Info("Getting transaction details")

	start := time.Now()
	txDetail, err := h.fabricClient.GetTransactionByID(txID)
	duration := time.Since(start)

	if err != nil {
		requestLogger.WithFields(logrus.Fields{
			"error":          err.Error(),
			"transaction_id": txID,
			"duration_ms":    duration.Milliseconds(),
		}).Error("Failed to get transaction details")

		statusCode := http.StatusInternalServerError
		message := fmt.Sprintf("Failed to get transaction details: %s", fabric.HandleFabricError(err))

		// Check if it's a "not found" error
		if strings.Contains(err.Error(), "not found") ||
			strings.Contains(err.Error(), "does not exist") ||
			strings.Contains(err.Error(), "no such transaction ID") {
			statusCode = http.StatusNotFound
			message = "Transaction not found"
		}

		writeErrorResponse(w, statusCode, message)
		return
	}

	requestLogger.WithFields(logrus.Fields{
		"transaction_id": txID,
		"block_number":   txDetail.BlockNumber,
		"duration_ms":    duration.Milliseconds(),
	}).Info("Transaction details retrieved successfully")

	writeJSONResponse(w, http.StatusOK, models.Response{
		Success: true,
		Message: "Transaction details retrieved successfully",
		Data:    txDetail,
	})
}