package config

import (
	"os"
	"testing"
)

func TestLoadModelsValidConfig(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: "reasoning"
    address: "reasoning-predictor.llm-serving:80"
    path: "/v1/chat/completions"
  - name: "ornith:35b"
    address: "ornith-predictor.llm-serving:80"
    path: "/v1/chat/completions"
  - name: "qwen2.5:3b-instruct"
    address: "ornith-predictor.llm-serving:80"
    path: "/v1/chat/completions"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	_, models, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err != nil {
		t.Fatalf("failed to load config: %v", err)
	}

	if len(models) != 3 {
		t.Errorf("expected 3 models, got %d", len(models))
	}

	// Test LookupModel
	cfg := &Config{Models: models}
	reasoning := cfg.LookupModel("reasoning")
	if reasoning == nil {
		t.Errorf("expected to find model 'reasoning'")
	}
	if reasoning.Address != "reasoning-predictor.llm-serving:80" {
		t.Errorf("expected address reasoning-predictor.llm-serving:80, got %s", reasoning.Address)
	}

	// Test case sensitivity
	notFound := cfg.LookupModel("Reasoning")
	if notFound != nil {
		t.Errorf("model lookup should be case-sensitive")
	}

	// Test ModelNames
	names := cfg.ModelNames()
	if len(names) != 3 {
		t.Errorf("expected 3 model names, got %d", len(names))
	}
}

func TestLoadModelsDuplicateName(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: "reasoning"
    address: "upstream1:80"
    path: "/v1/chat"
  - name: "reasoning"
    address: "upstream2:80"
    path: "/v1/chat"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	_, _, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err == nil {
		t.Errorf("expected error for duplicate model name, got nil")
	}
	if err.Error() != "duplicate model: \"reasoning\"" {
		t.Errorf("expected duplicate model error, got: %v", err)
	}
}

func TestLoadModelsEmptyName(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: ""
    address: "upstream:80"
    path: "/v1/chat"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	_, _, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err == nil {
		t.Errorf("expected error for empty model name, got nil")
	}
}

func TestLoadModelsMissingAddress(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: "reasoning"
    address: ""
    path: "/v1/chat"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	_, _, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err == nil {
		t.Errorf("expected error for missing address, got nil")
	}
	if err.Error() != "model \"reasoning\": 'address' or 'addresses' is required" {
		t.Errorf("expected missing address error, got: %v", err)
	}
}

func TestLoadModelsInvalidAddress(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: "reasoning"
    address: "invalid-address-no-port"
    path: "/v1/chat"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	_, _, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err == nil {
		t.Errorf("expected error for invalid address, got nil")
	}
}

func TestLoadModelsOptionalPath(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: "reasoning"
    address: "upstream:80"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	_, models, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err != nil {
		t.Fatalf("failed to load config: %v", err)
	}

	if len(models) != 1 {
		t.Errorf("expected 1 model, got %d", len(models))
	}

	model := models["reasoning"]
	if model.Path != "" {
		t.Errorf("expected empty path when not specified, got %s", model.Path)
	}
}

func TestModelSameUpstreamMultipleNames(t *testing.T) {
	data := `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false

models:
  - name: "ornith:35b"
    address: "ollama-pod:80"
    path: "/v1/chat"
  - name: "qwen2.5:3b"
    address: "ollama-pod:80"
    path: "/v1/chat"
`

	tmpFile, _ := os.CreateTemp("", "config-*.yaml")
	defer os.Remove(tmpFile.Name())
	tmpFile.WriteString(data)
	tmpFile.Close()

	routes, models, _, _, err := LoadRoutesAndModelsFromFile(tmpFile.Name())
	if err != nil {
		t.Fatalf("failed to load config: %v", err)
	}

	if len(models) != 2 {
		t.Errorf("expected 2 models, got %d", len(models))
	}

	// Both should resolve independently
	cfg := &Config{Routes: routes, Models: models}
	m1 := cfg.LookupModel("ornith:35b")
	m2 := cfg.LookupModel("qwen2.5:3b")

	if m1.Address != m2.Address {
		t.Errorf("expected both models to point to same upstream")
	}

	if m1 == m2 {
		t.Errorf("expected different ModelUpstream objects even for same address")
	}
}

// minimalRouteYAML is a valid routes block required by LoadRoutesAndModelsFromFile.
const minimalRouteYAML = `
routes:
  - name: test-route
    upstream:
      address: "localhost:8000"
      pathRewrite: ""
      connectTimeout: "10s"
      readTimeout: "30s"
      writeTimeout: "30s"
      maxBodySize: 1048576
      authRequired: false
`

// TestLoadModelsAddressesField verifies address / addresses YAML field handling.
func TestLoadModelsAddressesField(t *testing.T) {
	tests := []struct {
		name          string
		modelsYAML    string
		wantErr       bool
		errContains   string
		wantAddresses []string
		wantAddress   string
	}{
		{
			name: "single address field",
			modelsYAML: `
models:
  - name: "mymodel"
    address: "host:8080"
    path: "/v1/chat"
`,
			wantErr:       false,
			wantAddresses: []string{"host:8080"},
			wantAddress:   "host:8080",
		},
		{
			name: "multi addresses field",
			modelsYAML: `
models:
  - name: "mymodel"
    addresses:
      - "a:80"
      - "b:80"
    path: "/v1/chat"
`,
			wantErr:       false,
			wantAddresses: []string{"a:80", "b:80"},
			wantAddress:   "a:80",
		},
		{
			name: "neither field",
			modelsYAML: `
models:
  - name: "mymodel"
    path: "/v1/chat"
`,
			wantErr:     true,
			errContains: "mymodel",
		},
		{
			name: "invalid address format",
			modelsYAML: `
models:
  - name: "mymodel"
    address: "notavalidhostport"
    path: "/v1/chat"
`,
			wantErr:     true,
			errContains: "mymodel",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			data := minimalRouteYAML + tc.modelsYAML

			tmpFile, err := os.CreateTemp("", "config-*.yaml")
			if err != nil {
				t.Fatalf("CreateTemp: %v", err)
			}
			defer os.Remove(tmpFile.Name())
			tmpFile.WriteString(data)
			tmpFile.Close()

			_, models, _, _, loadErr := LoadRoutesAndModelsFromFile(tmpFile.Name())

			if tc.wantErr {
				if loadErr == nil {
					t.Fatalf("expected error, got nil")
				}
				if tc.errContains != "" && !containsStr(loadErr.Error(), tc.errContains) {
					t.Errorf("error %q does not contain %q", loadErr.Error(), tc.errContains)
				}
				return
			}

			if loadErr != nil {
				t.Fatalf("unexpected error: %v", loadErr)
			}

			m, ok := models["mymodel"]
			if !ok {
				t.Fatalf("model 'mymodel' not found in result")
			}

			if m.Address != tc.wantAddress {
				t.Errorf("Address: want %q, got %q", tc.wantAddress, m.Address)
			}

			if len(m.Addresses) != len(tc.wantAddresses) {
				t.Errorf("Addresses len: want %d, got %d (%v)", len(tc.wantAddresses), len(m.Addresses), m.Addresses)
			} else {
				for i, a := range tc.wantAddresses {
					if m.Addresses[i] != a {
						t.Errorf("Addresses[%d]: want %q, got %q", i, a, m.Addresses[i])
					}
				}
			}
		})
	}
}

// containsStr is a helper to avoid importing strings just for Contains.
func containsStr(s, sub string) bool {
	return len(s) >= len(sub) && (s == sub || len(sub) == 0 ||
		func() bool {
			for i := 0; i <= len(s)-len(sub); i++ {
				if s[i:i+len(sub)] == sub {
					return true
				}
			}
			return false
		}())
}