// Package output handles human-readable and JSON output formatting.
package output

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"
)

// JSONMode is true when --json flag is provided.
var JSONMode bool

// PrintJSON prints data as indented JSON to stdout.
func PrintJSON(v interface{}) {
	data, err := json.MarshalIndent(v, "", "  ")
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: cannot marshal JSON: %v\n", err)
		os.Exit(1)
	}
	fmt.Println(string(data))
}

// PrintKeyValue prints a set of key-value pairs in human-readable format.
func PrintKeyValue(pairs ...string) {
	if len(pairs)%2 != 0 {
		pairs = append(pairs, "")
	}
	maxKeyLen := 0
	for i := 0; i < len(pairs); i += 2 {
		if len(pairs[i]) > maxKeyLen {
			maxKeyLen = len(pairs[i])
		}
	}
	for i := 0; i < len(pairs); i += 2 {
		fmt.Printf("%-*s  %s\n", maxKeyLen, pairs[i]+":", pairs[i+1])
	}
}

// PrintTable prints a simple table with headers and rows.
func PrintTable(headers []string, rows [][]string) {
	if len(rows) == 0 {
		fmt.Println("(no results)")
		return
	}
	widths := make([]int, len(headers))
	for i, h := range headers {
		widths[i] = len(h)
	}
	for _, row := range rows {
		for i, cell := range row {
			if i < len(widths) && len(cell) > widths[i] {
				widths[i] = len(cell)
			}
		}
	}
	// header
	parts := make([]string, len(headers))
	for i, h := range headers {
		parts[i] = fmt.Sprintf("%-*s", widths[i], h)
	}
	fmt.Println(strings.Join(parts, "  "))
	// separator
	seps := make([]string, len(headers))
	for i := range headers {
		seps[i] = strings.Repeat("-", widths[i])
	}
	fmt.Println(strings.Join(seps, "  "))
	// rows
	for _, row := range rows {
		parts := make([]string, len(headers))
		for i := range headers {
			cell := ""
			if i < len(row) {
				cell = row[i]
			}
			parts[i] = fmt.Sprintf("%-*s", widths[i], cell)
		}
		fmt.Println(strings.Join(parts, "  "))
	}
}

// Error prints an error message to stderr and exits.
func Error(msg string) {
	fmt.Fprintln(os.Stderr, msg)
	os.Exit(1)
}

// Errorf prints a formatted error message to stderr and exits.
func Errorf(format string, args ...interface{}) {
	fmt.Fprintf(os.Stderr, format+"\n", args...)
	os.Exit(1)
}