package main

import (
	"os"
	"strings"
)

// dotEnvPath is the project-root .env the kernel reads keys from (config.loadDotEnv
// opens "./.env"). The settings panel writes secrets here so api_key_env resolves.
const dotEnvPath = ".env"

// upsertDotEnv sets KEY=value in ./.env (replacing an existing KEY line, else
// appending), and applies it to the running process so a rebuild picks it up
// without a restart. Comments and unrelated lines are preserved.
func upsertDotEnv(key, value string) error {
	key = strings.TrimSpace(key)
	if key == "" {
		return nil
	}
	var lines []string
	if b, err := os.ReadFile(dotEnvPath); err == nil {
		lines = strings.Split(strings.TrimRight(string(b), "\n"), "\n")
	}
	replaced := false
	for i, ln := range lines {
		t := strings.TrimSpace(ln)
		if t == "" || strings.HasPrefix(t, "#") {
			continue
		}
		if k, _, ok := strings.Cut(t, "="); ok && strings.TrimSpace(k) == key {
			lines[i] = key + "=" + value
			replaced = true
			break
		}
	}
	if !replaced {
		lines = append(lines, key+"="+value)
	}
	out := strings.Join(lines, "\n") + "\n"

	tmp, err := os.CreateTemp(".", ".env.*.tmp")
	if err != nil {
		return err
	}
	tmpPath := tmp.Name()
	if _, err := tmp.WriteString(out); err != nil {
		tmp.Close()
		os.Remove(tmpPath)
		return err
	}
	if err := tmp.Close(); err != nil {
		os.Remove(tmpPath)
		return err
	}
	if err := os.Rename(tmpPath, dotEnvPath); err != nil {
		os.Remove(tmpPath)
		return err
	}
	return os.Setenv(key, value)
}