package config

import (
	"os"
	"path/filepath"
	"sync"
	"testing"
	"time"
)

func writeTestConfig(t *testing.T, content string) string {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.yaml")
	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("write test config: %v", err)
	}
	return path
}

func TestLoadDefaults(t *testing.T) {
	path := writeTestConfig(t, `
server:
  host: "127.0.0.1"
  port: 9090
models:
  general-chat:
    provider: ollama
    actual_model: qwen2.5:0.5b
    endpoint: http://127.0.0.1:11434
    context_window: 32768
    max_output_tokens: 4096
    max_concurrency: 4
    residency: always
    cancel_supported: true
`)
	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}
	if cfg.Server.Port != 9090 {
		t.Errorf("expected port 9090, got %d", cfg.Server.Port)
	}
	if cfg.Scheduler.MaxRunningTasks != 8 {
		t.Errorf("expected default max_running_tasks 8, got %d", cfg.Scheduler.MaxRunningTasks)
	}
	if cfg.Timeouts.DefaultQueueMs != 5000 {
		t.Errorf("expected default queue_ms 5000, got %d", cfg.Timeouts.DefaultQueueMs)
	}
	if cfg.Context.SafetyMarginRatio != 0.08 {
		t.Errorf("expected default safety_margin 0.08, got %f", cfg.Context.SafetyMarginRatio)
	}
	if _, ok := cfg.Models["general-chat"]; !ok {
		t.Error("expected general-chat model in config")
	}
}

func TestValidate(t *testing.T) {
	path := writeTestConfig(t, `
scheduler:
  max_running_tasks: -1
`)
	_, err := Load(path)
	if err == nil {
		t.Error("expected validation error for max_running_tasks=-1")
	}
}

func TestValidateBackpressure(t *testing.T) {
	path := writeTestConfig(t, `
backpressure:
  level1_threshold: 0.90
  level2_threshold: 0.80
  level3_threshold: 0.95
`)
	_, err := Load(path)
	if err == nil {
		t.Error("expected validation error for level1 >= level2")
	}
}

func TestEnvOverride(t *testing.T) {
	path := writeTestConfig(t, `
server:
  port: 8080
`)
	os.Setenv("EDGEAI_SERVER_PORT", "9999")
	defer os.Unsetenv("EDGEAI_SERVER_PORT")

	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("Load failed: %v", err)
	}
	if cfg.Server.Port != 9999 {
		t.Errorf("expected port 9999 from env, got %d", cfg.Server.Port)
	}
}

func TestParsePriority(t *testing.T) {
	tests := []struct {
		input string
		want  int
	}{
		{"P0", 0}, {"P1", 1}, {"P2", 2}, {"P3", 3}, {"P4", 4},
		{"p0", 0}, {"invalid", 2}, {"", 2},
	}
	for _, tt := range tests {
		got := ParsePriority(tt.input)
		if got != tt.want {
			t.Errorf("ParsePriority(%q) = %d, want %d", tt.input, got, tt.want)
		}
	}
}

func TestPriorityName(t *testing.T) {
	if PriorityName(0) != "P0" {
		t.Errorf("expected P0, got %s", PriorityName(0))
	}
	if PriorityName(2) != "P2" {
		t.Errorf("expected P2, got %s", PriorityName(2))
	}
	if PriorityName(10) != "P2" {
		t.Errorf("expected P2 for out-of-range, got %s", PriorityName(10))
	}
}

func TestGetUpdate(t *testing.T) {
	cfg := &Config{}
	Update(cfg)
	time.Sleep(10 * time.Millisecond)
	got := Get()
	if got != cfg {
		t.Error("Get/Update mismatch")
	}
}

func TestConfigPath(t *testing.T) {
	os.Unsetenv("EDGEAI_CONFIG_PATH")
	if got := ConfigPath(); got != "configs/config.yaml" {
		t.Errorf("expected default path, got %s", got)
	}
	os.Setenv("EDGEAI_CONFIG_PATH", "/tmp/test.yaml")
	defer os.Unsetenv("EDGEAI_CONFIG_PATH")
	if got := ConfigPath(); got != "/tmp/test.yaml" {
		t.Errorf("expected env path, got %s", got)
	}
}

// Ensure package compiles with sync import.
var _ = sync.RWMutex{}