package handler

import (
	"fmt"
	"time"

	"accounting-app/pkg/api"
	"accounting-app/internal/models"
	"accounting-app/internal/service"

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

// ReportHandler handles HTTP requests for reports
type ReportHandler struct {
	reportService      *service.ReportService
	pdfExportService   *service.PDFExportService
	excelExportService *service.ExcelExportService
}

// NewReportHandler creates a new ReportHandler instance
func NewReportHandler(reportService *service.ReportService, pdfExportService *service.PDFExportService, excelExportService *service.ExcelExportService) *ReportHandler {
	return &ReportHandler{
		reportService:      reportService,
		pdfExportService:   pdfExportService,
		excelExportService: excelExportService,
	}
}

// GetTransactionSummaryRequest represents the request for transaction summary
type GetTransactionSummaryRequest struct {
	StartDate      string  `form:"start_date" binding:"required"`
	EndDate        string  `form:"end_date" binding:"required"`
	TargetCurrency *string `form:"target_currency"`
	ConversionDate *string `form:"conversion_date"`
}

// GetCategorySummaryRequest represents the request for category summary
type GetCategorySummaryRequest struct {
	StartDate       string  `form:"start_date" binding:"required"`
	EndDate         string  `form:"end_date" binding:"required"`
	TransactionType string  `form:"type" binding:"required,oneof=income expense"`
	TargetCurrency  *string `form:"target_currency"`
	ConversionDate  *string `form:"conversion_date"`
}

// GetTrendDataRequest represents the request for trend data
type GetTrendDataRequest struct {
	StartDate string  `form:"start_date" binding:"required"`
	EndDate   string  `form:"end_date" binding:"required"`
	Period    string  `form:"period" binding:"required,oneof=day week month year"`
	Currency  *string `form:"currency"`
}

// GetComparisonDataRequest represents the request for comparison data
type GetComparisonDataRequest struct {
	StartDate string  `form:"start_date" binding:"required"`
	EndDate   string  `form:"end_date" binding:"required"`
	Currency  *string `form:"currency"`
}

// GetAssetsSummaryRequest represents the request for assets summary
type GetAssetsSummaryRequest struct {
	TargetCurrency *string `form:"target_currency"`
	ConversionDate *string `form:"conversion_date"`
}

// GetTransactionSummary handles GET /api/v1/reports/summary
func (h *ReportHandler) GetTransactionSummary(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetTransactionSummaryRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse dates
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		api.BadRequest(c, "Invalid start_date format, expected YYYY-MM-DD")
		return
	}

	endDate, err := time.Parse("2006-01-02", req.EndDate)
	if err != nil {
		api.BadRequest(c, "Invalid end_date format, expected YYYY-MM-DD")
		return
	}

	// Validate date range
	if endDate.Before(startDate) {
		api.BadRequest(c, "end_date must be after start_date")
		return
	}

	// Parse optional target currency
	var targetCurrency *models.Currency
	if req.TargetCurrency != nil && *req.TargetCurrency != "" {
		currency := models.Currency(*req.TargetCurrency)
		// Validate currency
		if !isValidCurrency(currency) {
			api.BadRequest(c, "Invalid target_currency")
			return
		}
		targetCurrency = &currency
	}

	// Parse optional conversion date
	var conversionDate *time.Time
	if req.ConversionDate != nil && *req.ConversionDate != "" {
		date, err := time.Parse("2006-01-02", *req.ConversionDate)
		if err != nil {
			api.BadRequest(c, "Invalid conversion_date format, expected YYYY-MM-DD")
			return
		}
		conversionDate = &date
	}

	// Get summary
	summary, err := h.reportService.GetTransactionSummary(userId.(uint), startDate, endDate, targetCurrency, conversionDate)
	if err != nil {
		api.InternalError(c, "Failed to get transaction summary: "+err.Error())
		return
	}

	api.Success(c, summary)
}

// GetCategorySummary handles GET /api/v1/reports/category
func (h *ReportHandler) GetCategorySummary(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetCategorySummaryRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse dates
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		api.BadRequest(c, "Invalid start_date format, expected YYYY-MM-DD")
		return
	}

	endDate, err := time.Parse("2006-01-02", req.EndDate)
	if err != nil {
		api.BadRequest(c, "Invalid end_date format, expected YYYY-MM-DD")
		return
	}

	// Validate date range
	if endDate.Before(startDate) {
		api.BadRequest(c, "end_date must be after start_date")
		return
	}

	// Parse transaction type
	var transactionType models.TransactionType
	switch req.TransactionType {
	case "income":
		transactionType = models.TransactionTypeIncome
	case "expense":
		transactionType = models.TransactionTypeExpense
	default:
		api.BadRequest(c, "Invalid transaction type")
		return
	}

	// Parse optional target currency
	var targetCurrency *models.Currency
	if req.TargetCurrency != nil && *req.TargetCurrency != "" {
		currency := models.Currency(*req.TargetCurrency)
		// Validate currency
		if !isValidCurrency(currency) {
			api.BadRequest(c, "Invalid target_currency")
			return
		}
		targetCurrency = &currency
	}

	// Parse optional conversion date
	var conversionDate *time.Time
	if req.ConversionDate != nil && *req.ConversionDate != "" {
		date, err := time.Parse("2006-01-02", *req.ConversionDate)
		if err != nil {
			api.BadRequest(c, "Invalid conversion_date format, expected YYYY-MM-DD")
			return
		}
		conversionDate = &date
	}

	// Get summary
	summary, err := h.reportService.GetCategorySummary(userId.(uint), startDate, endDate, transactionType, targetCurrency, conversionDate)
	if err != nil {
		api.InternalError(c, "Failed to get category summary: "+err.Error())
		return
	}

	api.Success(c, summary)
}

// GetTrendData handles GET /api/v1/reports/trend
func (h *ReportHandler) GetTrendData(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetTrendDataRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse dates
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		api.BadRequest(c, "Invalid start_date format, expected YYYY-MM-DD")
		return
	}

	endDate, err := time.Parse("2006-01-02", req.EndDate)
	if err != nil {
		api.BadRequest(c, "Invalid end_date format, expected YYYY-MM-DD")
		return
	}

	// Validate date range
	if endDate.Before(startDate) {
		api.BadRequest(c, "end_date must be after start_date")
		return
	}

	// Parse period type
	var period service.PeriodType
	switch req.Period {
	case "day":
		period = service.PeriodTypeDay
	case "week":
		period = service.PeriodTypeWeek
	case "month":
		period = service.PeriodTypeMonth
	case "year":
		period = service.PeriodTypeYear
	default:
		api.BadRequest(c, "Invalid period type")
		return
	}

	// Parse optional currency
	var currency *models.Currency
	if req.Currency != nil && *req.Currency != "" {
		curr := models.Currency(*req.Currency)
		// Validate currency
		if !isValidCurrency(curr) {
			api.BadRequest(c, "Invalid currency")
			return
		}
		currency = &curr
	}

	// Get trend data
	trendData, err := h.reportService.GetTrendData(userId.(uint), startDate, endDate, period, currency)
	if err != nil {
		api.InternalError(c, "Failed to get trend data: "+err.Error())
		return
	}

	api.Success(c, trendData)
}

// GetComparisonData handles GET /api/v1/reports/comparison
func (h *ReportHandler) GetComparisonData(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetComparisonDataRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse dates
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		api.BadRequest(c, "Invalid start_date format, expected YYYY-MM-DD")
		return
	}

	endDate, err := time.Parse("2006-01-02", req.EndDate)
	if err != nil {
		api.BadRequest(c, "Invalid end_date format, expected YYYY-MM-DD")
		return
	}

	// Validate date range
	if endDate.Before(startDate) {
		api.BadRequest(c, "end_date must be after start_date")
		return
	}

	// Parse optional currency
	var currency *models.Currency
	if req.Currency != nil && *req.Currency != "" {
		curr := models.Currency(*req.Currency)
		// Validate currency
		if !isValidCurrency(curr) {
			api.BadRequest(c, "Invalid currency")
			return
		}
		currency = &curr
	}

	// Get comparison data
	comparisonData, err := h.reportService.GetComparisonData(userId.(uint), startDate, endDate, currency)
	if err != nil {
		api.InternalError(c, "Failed to get comparison data: "+err.Error())
		return
	}

	api.Success(c, comparisonData)
}

// GetAssetsSummary handles GET /api/v1/reports/assets
func (h *ReportHandler) GetAssetsSummary(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetAssetsSummaryRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse optional target currency
	var targetCurrency *models.Currency
	if req.TargetCurrency != nil && *req.TargetCurrency != "" {
		currency := models.Currency(*req.TargetCurrency)
		// Validate currency
		if !isValidCurrency(currency) {
			api.BadRequest(c, "Invalid target_currency")
			return
		}
		targetCurrency = &currency
	}

	// Parse optional conversion date
	var conversionDate *time.Time
	if req.ConversionDate != nil && *req.ConversionDate != "" {
		date, err := time.Parse("2006-01-02", *req.ConversionDate)
		if err != nil {
			api.BadRequest(c, "Invalid conversion_date format, expected YYYY-MM-DD")
			return
		}
		conversionDate = &date
	}

	// Get assets summary
	summary, err := h.reportService.GetAssetsSummary(userId.(uint), targetCurrency, conversionDate)
	if err != nil {
		api.InternalError(c, "Failed to get assets summary: "+err.Error())
		return
	}

	api.Success(c, summary)
}

// GetConsumptionHabitsRequest represents the request for consumption habits analysis
type GetConsumptionHabitsRequest struct {
	StartDate string  `form:"start_date" binding:"required"`
	EndDate   string  `form:"end_date" binding:"required"`
	Currency  *string `form:"currency"`
}

// GetConsumptionHabits handles GET /api/v1/reports/consumption-habits
func (h *ReportHandler) GetConsumptionHabits(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetConsumptionHabitsRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse dates
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		api.BadRequest(c, "Invalid start_date format, expected YYYY-MM-DD")
		return
	}

	endDate, err := time.Parse("2006-01-02", req.EndDate)
	if err != nil {
		api.BadRequest(c, "Invalid end_date format, expected YYYY-MM-DD")
		return
	}

	// Validate date range
	if endDate.Before(startDate) {
		api.BadRequest(c, "end_date must be after start_date")
		return
	}

	// Parse optional currency
	var currency *models.Currency
	if req.Currency != nil && *req.Currency != "" {
		curr := models.Currency(*req.Currency)
		// Validate currency
		if !isValidCurrency(curr) {
			api.BadRequest(c, "Invalid currency")
			return
		}
		currency = &curr
	}

	// Get consumption habits
	habits, err := h.reportService.GetConsumptionHabits(userId.(uint), startDate, endDate, currency)
	if err != nil {
		api.InternalError(c, "Failed to get consumption habits: "+err.Error())
		return
	}

	api.Success(c, habits)
}

// GetAssetLiabilityAnalysisRequest represents the request for asset liability analysis
type GetAssetLiabilityAnalysisRequest struct {
	IncludeTrend   bool    `form:"include_trend"`
	TrendStartDate *string `form:"trend_start_date"`
	TrendEndDate   *string `form:"trend_end_date"`
}

// GetAssetLiabilityAnalysis handles GET /api/v1/reports/asset-liability-analysis
func (h *ReportHandler) GetAssetLiabilityAnalysis(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req GetAssetLiabilityAnalysisRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse optional trend dates
	var trendStartDate, trendEndDate *time.Time
	if req.IncludeTrend {
		if req.TrendStartDate == nil || req.TrendEndDate == nil {
			api.BadRequest(c, "trend_start_date and trend_end_date are required when include_trend is true")
			return
		}

		startDate, err := time.Parse("2006-01-02", *req.TrendStartDate)
		if err != nil {
			api.BadRequest(c, "Invalid trend_start_date format, expected YYYY-MM-DD")
			return
		}
		trendStartDate = &startDate

		endDate, err := time.Parse("2006-01-02", *req.TrendEndDate)
		if err != nil {
			api.BadRequest(c, "Invalid trend_end_date format, expected YYYY-MM-DD")
			return
		}
		trendEndDate = &endDate

		// Validate date range
		if trendEndDate.Before(*trendStartDate) {
			api.BadRequest(c, "trend_end_date must be after trend_start_date")
			return
		}
	}

	// Get asset liability analysis
	analysis, err := h.reportService.GetAssetLiabilityAnalysis(userId.(uint), req.IncludeTrend, trendStartDate, trendEndDate)
	if err != nil {
		api.InternalError(c, "Failed to get asset liability analysis: "+err.Error())
		return
	}

	api.Success(c, analysis)
}

// isValidCurrency checks if a currency is supported
func isValidCurrency(currency models.Currency) bool {
	supportedCurrencies := models.SupportedCurrencies()
	for _, c := range supportedCurrencies {
		if c == currency {
			return true
		}
	}
	return false
}

// ExportReportRequest represents the request for exporting a report
type ExportReportRequest struct {
	StartDate      string  `json:"start_date" binding:"required"`
	EndDate        string  `json:"end_date" binding:"required"`
	TargetCurrency *string `json:"target_currency"`
	Format         string  `json:"format" binding:"required,oneof=pdf excel"`
}

// ExportReport handles POST /api/v1/reports/export
func (h *ReportHandler) ExportReport(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var req ExportReportRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		api.ValidationError(c, "Invalid request parameters: "+err.Error())
		return
	}

	// Parse dates
	startDate, err := time.Parse("2006-01-02", req.StartDate)
	if err != nil {
		api.BadRequest(c, "Invalid start_date format, expected YYYY-MM-DD")
		return
	}

	endDate, err := time.Parse("2006-01-02", req.EndDate)
	if err != nil {
		api.BadRequest(c, "Invalid end_date format, expected YYYY-MM-DD")
		return
	}

	// Validate date range
	if endDate.Before(startDate) {
		api.BadRequest(c, "end_date must be after start_date")
		return
	}

	// Parse optional target currency
	var targetCurrency *models.Currency
	if req.TargetCurrency != nil && *req.TargetCurrency != "" {
		currency := models.Currency(*req.TargetCurrency)
		// Validate currency
		if !isValidCurrency(currency) {
			api.BadRequest(c, "Invalid target_currency")
			return
		}
		targetCurrency = &currency
	}

	// Handle different export formats
	switch req.Format {
	case "pdf":
		// Export as PDF
		exportReq := service.ExportReportRequest{
			StartDate:      startDate,
			EndDate:        endDate,
			TargetCurrency: targetCurrency,
			IncludeCharts:  true,
		}

		pdfData, err := h.pdfExportService.ExportReportToPDF(userId.(uint), exportReq)
		if err != nil {
			api.InternalError(c, "Failed to export report as PDF: "+err.Error())
			return
		}

		// Set response headers for PDF download
		filename := fmt.Sprintf("report_%s_to_%s.pdf", startDate.Format("20060102"), endDate.Format("20060102"))
		c.Header("Content-Type", "application/pdf")
		c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
		c.Data(200, "application/pdf", pdfData)

	case "excel":
		// Export as Excel
		exportReq := service.ExportReportRequest{
			StartDate:      startDate,
			EndDate:        endDate,
			TargetCurrency: targetCurrency,
			IncludeCharts:  false, // Charts not supported in Excel yet
		}

		excelData, err := h.excelExportService.ExportReportToExcel(userId.(uint), exportReq)
		if err != nil {
			api.InternalError(c, "Failed to export report as Excel: "+err.Error())
			return
		}

		// Set response headers for Excel download
		filename := fmt.Sprintf("report_%s_to_%s.xlsx", startDate.Format("20060102"), endDate.Format("20060102"))
		c.Header("Content-Type", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
		c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))
		c.Data(200, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", excelData)

	default:
		api.BadRequest(c, "Unsupported export format")
		return
	}
}