package config

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

	ck "go.maximumdirect.net/configkit"
)

func loadResolution(t *testing.T, text string, overrides ...ck.Override) (*ck.Result[Config], error) {
	t.Helper()
	file := filepath.Join(t.TempDir(), "config.yml")
	if err := os.WriteFile(file, []byte(text), 0644); err != nil {
		t.Fatal(err)
	}
	return Load(ck.Input{Source: ck.File(file)}, "", overrides...)
}

func TestResolutionCopiesRootOverridesAndHonorsClears(t *testing.T) {
	document := `glossary_collections:
  party: {entries: []}
  spells: {entries: []}
glossaries: [party]
llm:
  proposal_profile: A
  repair_attempts: 2
context:
  description: root
pipeline:
  stages:
    - module: glossary
      glossaries: [party]
      llm:
        proposal_profile: B
        repair_attempts: 0
      context:
        description: ""
    - module: grammar
      protected_terms: null
    - module: grammar
      glossaries: []
`
	result, err := loadResolution(t, document, ck.Override{Path: ck.Keys("glossaries"), Value: []any{"spells"}, Flag: "--glossaries"})
	if err != nil {
		t.Fatal(err)
	}
	cfg := result.Config
	if !reflect.DeepEqual(cfg.ProtectedTerms, []string{"spells"}) || !reflect.DeepEqual(cfg.Pipeline.Stages[0].Glossaries, []string{"party"}) || !reflect.DeepEqual(cfg.Pipeline.Stages[1].Glossaries, []string{"spells"}) || len(cfg.Pipeline.Stages[2].Glossaries) != 0 {
		t.Fatalf("resolved: %+v", cfg)
	}
	if cfg.Pipeline.Stages[1].ProtectedTerms != nil || cfg.Pipeline.Stages[0].LLM.RepairAttempts != 0 || cfg.Pipeline.Stages[0].Context.Description != "" {
		t.Fatalf("clears lost: %+v", cfg.Pipeline.Stages)
	}
	if *cfg.Pipeline.Stages[0].LLM.ValidationProfile != "B" || *cfg.Pipeline.Stages[1].LLM.ValidationProfile != "A" {
		t.Fatalf("fallback: %+v", cfg.Pipeline.Stages)
	}
	cfg.Pipeline.Stages[0].ProtectedTerms[0] = "changed"
	if cfg.ProtectedTerms[0] != "spells" || cfg.Pipeline.Stages[2].ProtectedTerms[0] != "spells" {
		t.Fatal("selections share mutable storage")
	}
	info, ok := result.Explain(ck.Keys("pipeline", "stages").Index(0).Key("protected_terms"))
	if !ok || len(info.History) == 0 {
		t.Fatal("missing resolution evidence")
	}
}

func TestValidationProfileFallback(t *testing.T) {
	for _, tc := range []struct{ name, root, local, want string }{
		{"proposal override", "", "proposal_profile: B", "B"},
		{"inherited selection", "validation_profile: V", "proposal_profile: B", "V"},
		{"explicit null", "validation_profile: V", "proposal_profile: B\n        validation_profile: null", "B"},
		{"root null", "validation_profile: null", "proposal_profile: B", "B"},
		{"stage selection", "", "validation_profile: W", "W"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			doc := "llm:\n  proposal_profile: A\n"
			if tc.root != "" {
				doc += "  " + tc.root + "\n"
			}
			doc += "pipeline:\n  stages:\n    - module: grammar\n      llm:\n        " + tc.local + "\n"
			result, err := loadResolution(t, doc)
			if err != nil {
				t.Fatal(err)
			}
			value := result.Config.Pipeline.Stages[0].LLM.ValidationProfile
			if value == nil || *value != tc.want {
				t.Fatalf("profile=%v want=%s", value, tc.want)
			}
		})
	}
}

func TestResolvedSettingsValidation(t *testing.T) {
	for _, tc := range []struct{ name, text string }{
		{"unknown root collection", "glossaries: [missing]\n"},
		{"unknown local collection", "pipeline:\n  stages:\n    - module: grammar\n      protected_terms: [missing]\n"},
		{"empty id", "pipeline:\n  stages:\n    - {module: grammar, id: ''}\n"},
		{"duplicate id", "pipeline:\n  stages:\n    - {module: grammar, id: same}\n    - {module: grammar, id: same}\n"},
		{"empty root validation profile", "llm:\n  validation_profile: ''\n"},
		{"empty local validation profile", "pipeline:\n  stages:\n    - module: grammar\n      llm:\n        validation_profile: ''\n"},
		{"invalid local threshold", "pipeline:\n  stages:\n    - {module: grammar, confidence_threshold: 1.1}\n"},
		{"invalid local timeout", "pipeline:\n  stages:\n    - module: grammar\n      llm: {operation_timeout: 0s}\n"},
		{"invalid local batch budget", "pipeline:\n  stages:\n    - module: grammar\n      validation: {max_prompt_tokens: 0}\n"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			if _, err := loadResolution(t, tc.text); err == nil {
				t.Fatal("invalid settings accepted")
			}
		})
	}
	if _, err := loadResolution(t, "pipeline:\n  stages:\n    - {module: grammar, id: 'a/b not slug'}\n"); err != nil {
		t.Fatal(err)
	}
}

func TestResolutionRecordsFieldDependenciesAndExplicitNull(t *testing.T) {
	doc := `glossary_collections:
  party: {entries: []}
glossaries: [party]
llm:
  proposal_profile: A
pipeline:
  stages:
    - module: grammar
      llm:
        proposal_profile: B
        validation_profile: null
`
	result, err := loadResolution(t, doc)
	if err != nil {
		t.Fatal(err)
	}
	base := ck.Keys("pipeline", "stages").Index(0)
	for _, tc := range []struct{ path, dependency ck.Path }{
		{ck.Keys("protected_terms"), ck.Keys("glossaries")},
		{base.Key("glossaries"), ck.Keys("glossaries")},
		{base.Key("llm").Key("validation_profile"), base.Key("llm").Key("proposal_profile")},
	} {
		found := false
		for _, change := range result.Metadata().History(tc.path) {
			if change.Origin.Operation != ck.ChangeDerivedDefault {
				continue
			}
			for _, dependency := range change.Dependencies {
				if dependency.String() == tc.dependency.String() {
					found = true
				}
			}
		}
		if !found {
			t.Errorf("missing %s dependency on %s", tc.path.String(), tc.dependency.String())
		}
	}
	info, ok := result.Metadata().Lookup(base.Key("llm").Key("validation_profile"))
	if !ok || !info.Explicit {
		t.Fatalf("explicit null lost: %+v", info)
	}
}