// render.go — Go-based IEC 62443-3-3 SL2 compliance report renderer.
//
// Loads a JSON report produced by ansible-test and renders it through
// an external Go template file (report.gohtml by default).
//
// Usage:
//   go run render.go <report.json> [template.gohtml]
//
// The template receives the full JSON document as an untyped map.
// Registered template functions:
//   passIcon      — maps passed value to ✅/❌/🔍/❓
//   severityIcon  — maps severity string to 🔴/🟠/🟡/🟢/⚪
//   title         — capitalizes first letter of each word
//   divf          — float64 division (a/b*100) for percentages
//   add, sub      — integer arithmetic
//
// Dependencies:
//   golang.org/x/text v0.14.0 (for cases.Title)

package main

import (
	"encoding/json"
	"fmt"
	"os"
	"text/template"

	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Fprintf(os.Stderr, "Usage: gomplate-report <report.json> [template.gohtml]\n")
		os.Exit(1)
	}

	jsonPath := os.Args[1]
	tmplPath := "reports/report.gohtml"
	if len(os.Args) >= 3 {
		tmplPath = os.Args[2]
	}

	data, err := os.ReadFile(jsonPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error reading JSON: %v\n", err)
		os.Exit(1)
	}

	var report map[string]any
	if err := json.Unmarshal(data, &report); err != nil {
		fmt.Fprintf(os.Stderr, "Error parsing JSON: %v\n", err)
		os.Exit(1)
	}

	funcMap := template.FuncMap{
		"passIcon": func(v any) string {
			b, ok := v.(bool)
			if !ok {
				return "❓ MANUAL"
			}
			if b {
				return "✅ PASS"
			}
			return "❌ FAIL"
		},
		"severityIcon": func(s string) string {
			switch s {
			case "critical":
				return "🔴"
			case "high":
				return "🟠"
			case "medium":
				return "🟡"
			case "low":
				return "🟢"
			}
			return "⚪"
		},
		"title": cases.Title(language.English).String,
		"divf": func(a, b int) float64 {
			if b == 0 {
				return 0
			}
			return float64(a) / float64(b) * 100.0
		},
		"add": func(a, b int) int { return a + b },
		"sub": func(a, b int) int { return a - b },
	}

	tmpl, err := template.New("report.gohtml").Funcs(funcMap).ParseFiles(tmplPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error parsing template: %v\n", err)
		os.Exit(1)
	}

	if err := tmpl.ExecuteTemplate(os.Stdout, "report.gohtml", report); err != nil {
		fmt.Fprintf(os.Stderr, "Error rendering: %v\n", err)
		os.Exit(1)
	}
}