package config

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/spf13/pflag"
)

// clearEnv removes every GITFLOW_ variable so tests start from a known
// state regardless of the developer's shell.
func clearEnv(t *testing.T) {
	t.Helper()
	for _, kv := range os.Environ() {
		if strings.HasPrefix(kv, "GITFLOW_") {
			key := strings.SplitN(kv, "=", 2)[0]
			os.Unsetenv(key)
		}
	}
}

func loadWithFlags(t *testing.T, set func(f *pflag.FlagSet)) (*Config, error) {
	t.Helper()
	fs := NewFlagSet()
	if set != nil {
		set(fs)
	}
	return Load(fs)
}

func TestDefaults(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home) // no config file present

	cfg, err := loadWithFlags(t, nil)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Dir != "." {
		t.Errorf("Dir = %q, want %q", cfg.Dir, ".")
	}
	if cfg.Interval != 0 || cfg.MaxDepth != 0 {
		t.Errorf("Interval/MaxDepth = %v/%d, want 0/0", cfg.Interval, cfg.MaxDepth)
	}
	if cfg.Format != "table" || cfg.Workers != 8 {
		t.Errorf("Format/Workers = %q/%d, want table/8", cfg.Format, cfg.Workers)
	}
	if cfg.AI.Provider != "openai" || cfg.AI.Model != "gpt-4o" || cfg.AI.APIKeyEnv != "OPENAI_API_KEY" {
		t.Errorf("AI defaults wrong: %+v", cfg.AI)
	}
}

func TestFlagOverrides(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)

	cfg, err := loadWithFlags(t, func(f *pflag.FlagSet) {
		if err := f.Set("format", "compact"); err != nil {
			t.Fatal(err)
		}
		if err := f.Set("dir", "/tmp/x"); err != nil {
			t.Fatal(err)
		}
		if err := f.Set("workers", "4"); err != nil {
			t.Fatal(err)
		}
	})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Format != "compact" || cfg.Dir != "/tmp/x" || cfg.Workers != 4 {
		t.Errorf("flag overrides not applied: %+v", cfg)
	}
}

func TestEnvOverrides(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)
	t.Setenv("GITFLOW_FORMAT", "json")
	t.Setenv("GITFLOW_MAX_DEPTH", "3")
	t.Setenv("GITFLOW_AI_PROVIDER", "ollama")

	cfg, err := loadWithFlags(t, nil)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Format != "json" || cfg.MaxDepth != 3 || cfg.AI.Provider != "ollama" {
		t.Errorf("env overrides not applied: %+v", cfg)
	}
}

func TestFlagBeatsEnv(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)
	t.Setenv("GITFLOW_FORMAT", "json")

	cfg, err := loadWithFlags(t, func(f *pflag.FlagSet) {
		if err := f.Set("format", "compact"); err != nil {
			t.Fatal(err)
		}
	})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Format != "compact" {
		t.Errorf("Format = %q, want compact (flag must beat env)", cfg.Format)
	}
}

func TestConfigFile(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)
	content := "dir: /home/user/projects\nformat: json\nmax_depth: 2\ninterval: 5m\nexclude:\n  - node_modules\n  - vendor\n"
	if err := os.WriteFile(filepath.Join(home, ".gitflow.yaml"), []byte(content), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := loadWithFlags(t, nil)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Dir != "/home/user/projects" || cfg.Format != "json" || cfg.MaxDepth != 2 {
		t.Errorf("file values not applied: %+v", cfg)
	}
	if cfg.Interval != 5*time.Minute {
		t.Errorf("Interval = %v, want 5m", cfg.Interval)
	}
	if len(cfg.Exclude) != 2 || cfg.Exclude[0] != "node_modules" || cfg.Exclude[1] != "vendor" {
		t.Errorf("Exclude = %v, want [node_modules vendor]", cfg.Exclude)
	}
	if cfg.ConfigFile != filepath.Join(home, ".gitflow.yaml") {
		t.Errorf("ConfigFile = %q, want %q", cfg.ConfigFile, filepath.Join(home, ".gitflow.yaml"))
	}
}

func TestConfigPathEnvOverride(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)
	alt := filepath.Join(home, "custom.yaml")
	if err := os.WriteFile(alt, []byte("format: compact\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	t.Setenv("GITFLOW_CONFIG", alt)

	cfg, err := loadWithFlags(t, nil)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Format != "compact" {
		t.Errorf("Format = %q, want compact from GITFLOW_CONFIG file", cfg.Format)
	}
}

func TestValidateRejectsBadFormat(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)

	if _, err := loadWithFlags(t, func(f *pflag.FlagSet) {
		if err := f.Set("format", "xml"); err != nil {
			t.Fatal(err)
		}
	}); err == nil {
		t.Error("Load(bad format) succeeded, want error")
	}
}

func TestValidateRejectsBadWorkers(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)

	if _, err := loadWithFlags(t, func(f *pflag.FlagSet) {
		if err := f.Set("workers", "0"); err != nil {
			t.Fatal(err)
		}
	}); err == nil {
		t.Error("Load(workers=0) succeeded, want error")
	}
}

func TestDump(t *testing.T) {
	clearEnv(t)
	home := t.TempDir()
	t.Setenv("HOME", home)

	cfg, err := loadWithFlags(t, nil)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	out, err := cfg.Dump()
	if err != nil {
		t.Fatalf("Dump: %v", err)
	}
	for _, want := range []string{"dir:", "interval:", "format:", "workers:", "ai:", "provider:"} {
		if !strings.Contains(out, want) {
			t.Errorf("Dump() missing %q:\n%s", want, out)
		}
	}
}