package reports

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"time"

	"punchcard/internal/queries"
	"punchcard/templates"
)

// RecordInvoice records the invoice in the database after successful generation
func RecordInvoice(q *queries.Queries, year, month, number, clientID, totalAmountCents int64) error {
	_, err := q.CreateInvoice(context.Background(), queries.CreateInvoiceParams{
		Year:        year,
		Month:       month,
		Number:      number,
		ClientID:    clientID,
		TotalAmount: totalAmountCents,
	})
	if err != nil {
		return fmt.Errorf("failed to record invoice in database: %w", err)
	}
	return nil
}

// InvoiceJSONData represents the data structure for the JSON file that Typst will consume
type InvoiceJSONData struct {
	ClientName      string     `json:"client_name"`
	ProjectName     string     `json:"project_name"`
	DateRangeStart  string     `json:"date_range_start"`
	DateRangeEnd    string     `json:"date_range_end"`
	GeneratedDate   string     `json:"generated_date"`
	InvoiceNumber   string     `json:"invoice_number"`
	ContractorName  string     `json:"contractor_name"`
	ContractorLabel string     `json:"contractor_label"`
	ContractorEmail string     `json:"contractor_email"`
	LineItems       []LineItem `json:"line_items"`
	TotalHours      float64    `json:"total_hours"`
	TotalAmount     float64    `json:"total_amount"`
}

func GenerateInvoicePDF(invoiceData *InvoiceData, outputPath string) error {
	// Check if Typst is installed
	if err := checkTypstInstalled(); err != nil {
		return err
	}

	// Create temporary directory for template and data files
	tempDir, err := os.MkdirTemp("", "punchcard-invoice")
	if err != nil {
		return fmt.Errorf("failed to create temp directory: %w", err)
	}
	defer os.RemoveAll(tempDir)

	// Create JSON data for Typst template
	jsonData := InvoiceJSONData{
		ClientName:     invoiceData.ClientName,
		ProjectName:    invoiceData.ProjectName,
		DateRangeStart: invoiceData.DateRange.Start.Format("2006-01-02"),
		DateRangeEnd:   invoiceData.DateRange.End.Format("2006-01-02"),
		GeneratedDate:  invoiceData.GeneratedDate.Format("2006-01-02"),
		InvoiceNumber: fmt.Sprintf("%04d-%02d-%03d",
			invoiceData.DateRange.Start.Year(),
			invoiceData.DateRange.Start.Month(),
			invoiceData.InvoiceNumber,
		),
		ContractorName:  invoiceData.ContractorName,
		ContractorLabel: invoiceData.ContractorLabel,
		ContractorEmail: invoiceData.ContractorEmail,
		LineItems:       invoiceData.LineItems,
		TotalHours:      invoiceData.TotalHours,
		TotalAmount:     invoiceData.TotalAmount,
	}

	// Write JSON data file
	dataFile := filepath.Join(tempDir, "data.json")
	jsonBytes, err := json.MarshalIndent(jsonData, "", "  ")
	if err != nil {
		return fmt.Errorf("failed to marshal JSON data: %w", err)
	}

	if err := os.WriteFile(dataFile, jsonBytes, 0o644); err != nil {
		return fmt.Errorf("failed to write JSON data file: %w", err)
	}

	// Write Typst template file
	typstFile := filepath.Join(tempDir, "invoice.typ")
	if err := os.WriteFile(typstFile, []byte(templates.InvoiceTemplate), 0o644); err != nil {
		return fmt.Errorf("failed to write Typst template file: %w", err)
	}

	// Generate PDF using Typst
	cmd := exec.Command("typst", "compile", typstFile, outputPath)
	cmd.Dir = tempDir // Set working directory so Typst can find data.json

	if output, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("failed to generate PDF: %w\nTypst output: %s", err, string(output))
	}

	return nil
}

func checkTypstInstalled() error {
	_, err := exec.LookPath("typst")
	if err != nil {
		return fmt.Errorf("typst is not installed or not in PATH. Please install Typst from https://typst.org/")
	}
	return nil
}

func GenerateDefaultInvoiceFilename(clientName, projectName string, dateRange DateRange) string {
	var name string
	if projectName != "" {
		name = fmt.Sprintf("%s_%s", clientName, projectName)
	} else {
		name = clientName
	}

	// Replace spaces and special characters
	name = filepath.Base(name)

	dateStr := dateRange.Start.Format("2006-01")
	timestamp := time.Now().Format("20060102_150405")

	return fmt.Sprintf("invoice_%s_%s_%s.pdf", name, dateStr, timestamp)
}