package main

import (
	"context"
	"encoding/json"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"strings"

	"github.com/jackc/pgx/v5/pgxpool"

	"shop/internal/check"
)

func main() {
	loadDotEnv()

	skipDB := os.Getenv("CHECK_SKIP_DB") == "1"
	hostTools := os.Getenv("CHECK_HOST_TOOLS") != "0"

	ctx := context.Background()
	report := check.AppInfo()
	if hostTools {
		report.Items = append(report.Items, check.ToolVersions(ctx)...)
	}

	dbURL := os.Getenv("DATABASE_URL")
	if skipDB {
		report.Items = append(report.Items, check.Item{
			Name:   "database",
			Status: check.StatusWarn,
			Detail: "проверка отложена — сначала выполните: docker compose up -d, затем ./check.sh --after-start",
		})
	} else if dbURL == "" {
		report.Items = append(report.Items, check.Item{
			Name:   "database",
			Status: check.StatusWarn,
			Detail: "DATABASE_URL не задан — запустите: ./install.sh",
		})
	} else {
		appendDBChecks(ctx, &report, dbURL)
	}

	enc := json.NewEncoder(os.Stdout)
	enc.SetIndent("", "  ")
	_ = enc.Encode(report)

	fmt.Println()
	printSummary(report)

	if !report.Healthy() {
		os.Exit(1)
	}
}

func appendDBChecks(ctx context.Context, report *check.Report, dbURL string) {
	pool, err := pgxpool.New(ctx, dbURL)
	if err != nil {
		report.Items = append(report.Items, dbCheckItem(err, dbURL))
		return
	}
	defer pool.Close()

	dbItems, err := check.Database(ctx, pool)
	if err != nil {
		report.Items = append(report.Items, check.Item{
			Name:   "database",
			Status: dbCheckStatus(err, dbURL),
			Detail: err.Error(),
		})
		return
	}
	report.Items = append(report.Items, dbItems...)
}

func dbCheckItem(err error, dbURL string) check.Item {
	return check.Item{
		Name:   "database",
		Status: dbCheckStatus(err, dbURL),
		Detail: err.Error(),
	}
}

func dbCheckStatus(err error, dbURL string) check.Status {
	if err == nil {
		return check.StatusOK
	}
	msg := strings.ToLower(err.Error())
	if isDockerInternalHost(dbURL) && (strings.Contains(msg, "no such host") ||
		strings.Contains(msg, "name or service not known") ||
		strings.Contains(msg, "hostname resolving")) {
		return check.StatusWarn
	}
	return check.StatusError
}

func isDockerInternalHost(dbURL string) bool {
	u, err := url.Parse(dbURL)
	if err != nil {
		return false
	}
	host := u.Hostname()
	return host == "postgres" || host == "db" || host == "shop-postgres"
}

func printSummary(r check.Report) {
	fmt.Printf("ShopNova %s | %s\n\n", r.AppVersion, r.GoVersion)
	for _, it := range r.Items {
		mark := "✓"
		switch it.Status {
		case check.StatusWarn:
			mark = "!"
		case check.StatusError:
			mark = "✗"
		}
		line := fmt.Sprintf("  %s %-18s %s", mark, it.Name+":", it.Detail)
		if it.Expected != "" {
			line += " (ожидается " + it.Expected + ")"
		}
		fmt.Println(line)
	}
}

func loadDotEnv() {
	root, _ := os.Getwd()
	path := filepath.Join(root, ".env")
	data, err := os.ReadFile(path)
	if err != nil {
		return
	}
	for _, line := range splitLines(string(data)) {
		line = trimComment(line)
		if line == "" {
			continue
		}
		k, v, ok := splitKV(line)
		if !ok {
			continue
		}
		if os.Getenv(k) == "" {
			_ = os.Setenv(k, v)
		}
	}
}

func splitLines(s string) []string {
	var lines []string
	start := 0
	for i := 0; i < len(s); i++ {
		if s[i] == '\n' {
			lines = append(lines, s[start:i])
			start = i + 1
		}
	}
	if start < len(s) {
		lines = append(lines, s[start:])
	}
	return lines
}

func trimComment(s string) string {
	if i := indexByte(s, '#'); i >= 0 {
		s = s[:i]
	}
	for len(s) > 0 && (s[len(s)-1] == ' ' || s[len(s)-1] == '\r') {
		s = s[:len(s)-1]
	}
	for len(s) > 0 && s[0] == ' ' {
		s = s[1:]
	}
	return s
}

func splitKV(s string) (string, string, bool) {
	for i := 0; i < len(s); i++ {
		if s[i] == '=' {
			return s[:i], s[i+1:], true
		}
	}
	return "", "", false
}

func indexByte(s string, c byte) int {
	for i := 0; i < len(s); i++ {
		if s[i] == c {
			return i
		}
	}
	return -1
}