package config

import (
	"fmt"
	"strings"
)

// sampleEntry is one line pair in the sample env file: a comment and the
// (usually commented-out) KEY=VALUE line.
type sampleEntry struct {
	name    string
	value   string
	comment string
	active  bool // rendered uncommented
}

// SampleEnv renders a sample .env file covering every setting, each with a
// comment line. Everything is commented out — so all defaults apply —
// except LOG_FILE when logFile is non-empty: a Windows service has no
// console, so the installer pre-wires file logging there.
func SampleEnv(logFile string) string {
	entries := []sampleEntry{
		{"LISTEN_OLLAMA", ":11434", "Ollama-facing listener address", false},
		{"LISTEN_COMFY", ":8188", "ComfyUI-facing listener address", false},
		{"OLLAMA_URL", "http://127.0.0.1:11434", "Ollama upstream URL; setting it enables the Ollama consumer (default: empty = disabled)", false},
		{"COMFY_URL", "http://127.0.0.1:8188", "ComfyUI upstream URL; setting it enables the ComfyUI consumer (default: empty = disabled)", false},
		{"WARM_MODEL", "", "Optional model to reload after an image job (default: empty = none)", false},
		{"UNLOAD_TIMEOUT", "60s", "How long to wait for Ollama to unload a model", false},
		{"JOB_TIMEOUT", "15m", "Maximum time to wait for a ComfyUI job", false},
		{"LLM_WAIT_TIMEOUT", "10m", "Max time an LLM request waits for the GPU before being answered 503 (wait mode)", false},
		{"LLM_BUSY_MODE", "wait", `How blocked LLM requests are handled: "wait" holds them, "reject" fails them immediately`, false},
		{"LLM_BUSY_STATUS", "503", "HTTP status for rejected LLM requests in reject mode (400-599, e.g. 429)", false},
		{"BUSY_RETRY_AFTER", "30", "Seconds sent as Retry-After on busy responses (both modes)", false},
		{"LOGLEVEL", "warn", `Log verbosity: debug, info, warn, error; "info" logs every request (LOG_LEVEL works too)`, false},
		{"LOG_FORMAT", "text", `Log format: "text" or "json"`, false},
		{"LOG_FILE", logFile, "Append logs to this file instead of stderr (a Windows service has no console)", logFile != ""},
		{"UNLOAD_POLL_INTERVAL", "500ms", "/api/ps poll interval while unloading", false},
		{"HISTORY_POLL_INTERVAL", "1s", "/history/<id> poll interval while a job runs", false},
		{"PROBE_TIMEOUT", "5s", "Startup probe timeout for the enabled upstreams", false},
		{"FREE_TIMEOUT", "30s", "Timeout for the POST /free call after an image job", false},
		{"WARM_TIMEOUT", "2m", "Timeout for the warm-model reload after an image job", false},
		{"SHUTDOWN_TIMEOUT", "10s", "Graceful shutdown timeout on SIGINT/SIGTERM", false},
		{"BACKOFF_INITIAL", "1s", "First retry wait when an upstream connection fails", false},
		{"BACKOFF_MAX", "60s", "Cap for the exponential retry backoff", false},
		{"PROMPT_CAPTURE_LIMIT", "65536", "Bytes of the /prompt response buffered to find prompt_id (pass-through unaffected)", false},
		{"AUTO_UPDATE", "true", "Poll the releases API for signed updates", false},
		{"UPDATE_INTERVAL", "6h", "Auto-update check interval", false},
		{"UPDATE_REPO", "https://git.rambossek.at/PUBLIC/gpu-turnstile", "Repository to check for releases", false},
		{"UPDATE_ASSET", "gpu-turnstile.exe", "Release asset to download", false},
	}
	var b strings.Builder
	b.WriteString("# gpu-turnstile configuration\n")
	b.WriteString("# KEY=VALUE lines; \"#\" starts a comment. Every setting below is at its\n")
	b.WriteString("# default and commented out — remove the \"#\" to change it.\n")
	b.WriteString("# At least one of OLLAMA_URL / COMFY_URL must be set for the proxy to start.\n\n")
	for _, e := range entries {
		fmt.Fprintf(&b, "# %s\n", e.comment)
		if e.active {
			fmt.Fprintf(&b, "%s=%s\n\n", e.name, e.value)
		} else {
			fmt.Fprintf(&b, "#%s=%s\n\n", e.name, e.value)
		}
	}
	return b.String()
}