package prompts

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

func TestLoadAnalysisPromptProjectLocal(t *testing.T) {
	tmpDir := t.TempDir()
	promptDir := filepath.Join(tmpDir, ".grokkit", "prompts")
	if err := os.MkdirAll(promptDir, 0755); err != nil {
		t.Fatal(err)
	}

	expected := "You are a Go expert educator."
	if err := os.WriteFile(filepath.Join(promptDir, "go.md"), []byte(expected), 0644); err != nil {
		t.Fatal(err)
	}

	path, content, err := LoadAnalysisPrompt(tmpDir, "go")
	if err != nil {
		t.Fatalf("LoadAnalysisPrompt failed: %v", err)
	}
	if content != expected {
		t.Errorf("content = %q, want %q", content, expected)
	}
	if !filepath.IsAbs(path) || path == "" {
		// path should be meaningful
		t.Logf("returned path: %s", path)
	}
}

func TestLoadAnalysisPromptGlobalFallback(t *testing.T) {
	projectDir := t.TempDir() // no .grokkit/prompts here
	globalDir := t.TempDir()

	promptDir := filepath.Join(globalDir, ".config", "grokkit", "prompts")
	if err := os.MkdirAll(promptDir, 0755); err != nil {
		t.Fatal(err)
	}

	expected := "You are a Python expert."
	if err := os.WriteFile(filepath.Join(promptDir, "python.md"), []byte(expected), 0644); err != nil {
		t.Fatal(err)
	}

	// Override HOME to point to our temp global dir
	oldHome := os.Getenv("HOME")
	defer func() { _ = os.Setenv("HOME", oldHome) }()
	_ = os.Setenv("HOME", globalDir)

	path, content, err := LoadAnalysisPrompt(projectDir, "python")
	if err != nil {
		t.Fatalf("LoadAnalysisPrompt (global fallback) failed: %v", err)
	}
	if content != expected {
		t.Errorf("content = %q, want %q", content, expected)
	}
	_ = path
}

func TestLoadAnalysisPromptProjectOverridesGlobal(t *testing.T) {
	projectDir := t.TempDir()
	globalDir := t.TempDir()

	// Create both project-local and global prompts
	localPromptDir := filepath.Join(projectDir, ".grokkit", "prompts")
	if err := os.MkdirAll(localPromptDir, 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(localPromptDir, "go.md"), []byte("local prompt"), 0644); err != nil {
		t.Fatal(err)
	}

	globalPromptDir := filepath.Join(globalDir, ".config", "grokkit", "prompts")
	if err := os.MkdirAll(globalPromptDir, 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(globalPromptDir, "go.md"), []byte("global prompt"), 0644); err != nil {
		t.Fatal(err)
	}

	oldHome := os.Getenv("HOME")
	defer func() { _ = os.Setenv("HOME", oldHome) }()
	_ = os.Setenv("HOME", globalDir)

	_, content, err := LoadAnalysisPrompt(projectDir, "go")
	if err != nil {
		t.Fatalf("LoadAnalysisPrompt failed: %v", err)
	}
	if content != "local prompt" {
		t.Errorf("expected project-local to override global, got: %q", content)
	}
}

func TestLoadAnalysisPromptNotFound(t *testing.T) {
	projectDir := t.TempDir()
	emptyHome := t.TempDir()

	oldHome := os.Getenv("HOME")
	defer func() { _ = os.Setenv("HOME", oldHome) }()
	_ = os.Setenv("HOME", emptyHome)

	_, _, err := LoadAnalysisPrompt(projectDir, "rust")
	if err == nil {
		t.Fatal("expected error when no prompt found, got nil")
	}
	if !os.IsNotExist(err) {
		t.Errorf("expected os.ErrNotExist, got: %v", err)
	}
}

func TestLoadAnalysisPromptDefaultsToGo(t *testing.T) {
	projectDir := t.TempDir()
	promptDir := filepath.Join(projectDir, ".grokkit", "prompts")
	if err := os.MkdirAll(promptDir, 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(promptDir, "go.md"), []byte("go prompt"), 0644); err != nil {
		t.Fatal(err)
	}

	tests := []struct {
		name     string
		language string
	}{
		{"empty string defaults to go", ""},
		{"unknown defaults to go", "unknown"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			_, content, err := LoadAnalysisPrompt(projectDir, tt.language)
			if err != nil {
				t.Fatalf("LoadAnalysisPrompt(%q) failed: %v", tt.language, err)
			}
			if content != "go prompt" {
				t.Errorf("expected go prompt, got: %q", content)
			}
		})
	}
}

func TestLoadAnalysisPromptNormalizesCase(t *testing.T) {
	projectDir := t.TempDir()
	promptDir := filepath.Join(projectDir, ".grokkit", "prompts")
	if err := os.MkdirAll(promptDir, 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(promptDir, "python.md"), []byte("python prompt"), 0644); err != nil {
		t.Fatal(err)
	}

	_, content, err := LoadAnalysisPrompt(projectDir, "Python")
	if err != nil {
		t.Fatalf("LoadAnalysisPrompt with uppercase failed: %v", err)
	}
	if content != "python prompt" {
		t.Errorf("expected case-insensitive match, got: %q", content)
	}
}