package profile

import (
	"context"
	"errors"
	"fmt"
	"io/fs"
	"reflect"
	"strings"
	"sync"
	"testing"
	"testing/fstest"

	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
)

func TestResolvingRepositoryMergesProfileChain(t *testing.T) {
	repo := &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
		"leaf": {
			ID:              "leaf",
			BaseProfileID:   "middle",
			BackendID:       "leaf-backend",
			TopP:            0.8,
			TimeoutSeconds:  45,
			ReasoningEffort: "high",
		},
		"middle": {
			ID:             "middle",
			BaseProfileID:  "root",
			Endpoint:       "https://middle.example/v1",
			Model:          "middle-model",
			MaxTokens:      256,
			APIKeyEnv:      "MIDDLE_API_KEY",
			APIKeyRequired: true,
			ExtraParams:    map[string]any{"middle": map[string]any{"value": "middle"}},
		},
		"root": {
			ID:          "root",
			BackendID:   "root-backend",
			Endpoint:    "https://root.example/v1",
			Model:       "root-model",
			Temperature: 0.3,
			ServiceTier: "priority",
			ExtraParams: map[string]any{"root": "value"},
		},
	}}

	got, err := NewResolvingRepository(repo).GetProfile(context.Background(), "leaf")
	if err != nil {
		t.Fatalf("resolve profile: %v", err)
	}
	want := &domain.ExecutionProfile{
		ID:              "leaf",
		BackendID:       "leaf-backend",
		Endpoint:        "https://middle.example/v1",
		Model:           "middle-model",
		Temperature:     0.3,
		MaxTokens:       256,
		TopP:            0.8,
		TimeoutSeconds:  45,
		ServiceTier:     "priority",
		ReasoningEffort: "high",
		APIKeyEnv:       "MIDDLE_API_KEY",
		APIKeyRequired:  true,
		ExtraParams:     map[string]any{"middle": map[string]any{"value": "middle"}},
	}
	if !reflect.DeepEqual(got, want) {
		t.Fatalf("resolved profile:\n got %#v\nwant %#v", got, want)
	}
}

func TestResolvingRepositoryRejectsMissingSourceAndProfileID(t *testing.T) {
	if _, err := NewResolvingRepository(nil).GetProfile(context.Background(), "profile"); !errors.Is(err, ErrInvalidProfile) {
		t.Fatalf("nil source error = %v, want ErrInvalidProfile", err)
	}

	repo := &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{}}
	if _, err := NewResolvingRepository(repo).GetProfile(context.Background(), " \t "); !errors.Is(err, ErrInvalidProfile) {
		t.Fatalf("blank id error = %v, want ErrInvalidProfile", err)
	}
	if got := repo.callCount(" "); got != 0 {
		t.Fatalf("blank id looked up source %d times", got)
	}
}

func TestResolvingRepositoryCopiesExtraParams(t *testing.T) {
	baseParams := map[string]any{"nested": map[string]any{"value": "base"}}
	repo := &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
		"child": {ID: "child", BaseProfileID: "base"},
		"base": {
			ID:          "base",
			Endpoint:    "https://base.example/v1",
			Model:       "model",
			ExtraParams: baseParams,
		},
	}}
	resolver := NewResolvingRepository(repo)

	first, err := resolver.GetProfile(context.Background(), "child")
	if err != nil {
		t.Fatalf("resolve inherited map: %v", err)
	}
	first.ExtraParams["nested"].(map[string]any)["value"] = "mutated"
	second, err := resolver.GetProfile(context.Background(), "child")
	if err != nil {
		t.Fatalf("resolve inherited map again: %v", err)
	}
	if got := second.ExtraParams["nested"].(map[string]any)["value"]; got != "base" {
		t.Fatalf("later result retained mutation: %v", got)
	}
	if got := baseParams["nested"].(map[string]any)["value"]; got != "base" {
		t.Fatalf("source map retained mutation: %v", got)
	}

	repo.set("child", &domain.ExecutionProfile{
		ID:            "child",
		BaseProfileID: "base",
		ExtraParams:   map[string]any{"child": "replacement"},
	})
	replaced, err := resolver.GetProfile(context.Background(), "child")
	if err != nil {
		t.Fatalf("resolve replacement map: %v", err)
	}
	if !reflect.DeepEqual(replaced.ExtraParams, map[string]any{"child": "replacement"}) {
		t.Fatalf("extra params = %#v, want complete child replacement", replaced.ExtraParams)
	}
}

func TestResolvingRepositoryUsesRawOverlayForEachLookup(t *testing.T) {
	leafSource := NewFSRepository(profileTestFS(map[string]string{
		"leaf.yaml": "id: leaf\nbase_profile: base\n",
	}), ".")
	fallback := NewFSRepository(profileTestFS(map[string]string{
		"base.yaml": "id: base\nendpoint: https://fallback.example/v1\nmodel: fallback-model\n",
	}), ".")
	overlay := NewOverlayRepository(leafSource, fallback)
	resolver := NewResolvingRepository(overlay)

	got, err := resolver.GetProfile(context.Background(), "leaf")
	if err != nil {
		t.Fatalf("resolve fallback base: %v", err)
	}
	if got.Model != "fallback-model" {
		t.Fatalf("fallback base model = %q", got.Model)
	}

	shadowing := NewOverlayRepository(NewFSRepository(profileTestFS(map[string]string{
		"leaf.yaml": "id: leaf\nbase_profile: base\n",
		"base.yaml": "id: base\nendpoint: https://primary.example/v1\nmodel: primary-model\n",
	}), "."), fallback)
	got, err = NewResolvingRepository(shadowing).GetProfile(context.Background(), "leaf")
	if err != nil {
		t.Fatalf("resolve shadowed base: %v", err)
	}
	if got.Model != "primary-model" || got.Endpoint != "https://primary.example/v1" {
		t.Fatalf("shadowed base = %+v", got)
	}
}

func TestResolvingRepositoryReportsSafetyAndSourceErrors(t *testing.T) {
	sourceErr := errors.New("source failure")
	tests := []struct {
		name     string
		repo     *resolvingTestRepository
		id       string
		want     []error
		wantNot  error
		contains []string
	}{
		{
			name:    "missing selected profile preserves not found",
			repo:    &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{}},
			id:      "missing",
			want:    []error{ErrProfileNotFound},
			wantNot: ErrInvalidProfile,
		},
		{
			name: "missing base is invalid but not not found",
			repo: &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
				"leaf": {ID: "leaf", BaseProfileID: "missing"},
			}},
			id:       "leaf",
			want:     []error{ErrInvalidProfile},
			wantNot:  ErrProfileNotFound,
			contains: []string{"missing", "leaf -> missing"},
		},
		{
			name: "direct cycle",
			repo: &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
				"a": {ID: "a", BaseProfileID: "a"},
			}},
			id:       "a",
			want:     []error{ErrInvalidProfile},
			contains: []string{"a -> a"},
		},
		{
			name: "indirect cycle",
			repo: &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
				"a": {ID: "a", BaseProfileID: "b"},
				"b": {ID: "b", BaseProfileID: "c"},
				"c": {ID: "c", BaseProfileID: "a"},
			}},
			id:       "a",
			want:     []error{ErrInvalidProfile},
			contains: []string{"a -> b -> c -> a"},
		},
		{
			name: "nil result",
			repo: &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
				"leaf": nil,
			}},
			id:   "leaf",
			want: []error{ErrInvalidProfile},
		},
		{
			name: "incomplete resolved profile",
			repo: &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
				"leaf": {ID: "leaf", BaseProfileID: "base"},
				"base": {ID: "base", Model: "model"},
			}},
			id:   "leaf",
			want: []error{ErrInvalidProfile},
		},
		{
			name: "base source error is retained",
			repo: &resolvingTestRepository{
				profiles: map[string]*domain.ExecutionProfile{"leaf": {ID: "leaf", BaseProfileID: "base"}},
				errors:   map[string]error{"base": sourceErr},
			},
			id:   "leaf",
			want: []error{ErrInvalidProfile, sourceErr},
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			_, err := NewResolvingRepository(tc.repo).GetProfile(context.Background(), tc.id)
			for _, want := range tc.want {
				if !errors.Is(err, want) {
					t.Fatalf("error = %v, want %v", err, want)
				}
			}
			if tc.wantNot != nil && errors.Is(err, tc.wantNot) {
				t.Fatalf("error = %v, must not match %v", err, tc.wantNot)
			}
			for _, fragment := range tc.contains {
				if !strings.Contains(err.Error(), fragment) {
					t.Fatalf("error = %v, want %q", err, fragment)
				}
			}
		})
	}
}

func TestResolvingRepositoryEnforcesChainLength(t *testing.T) {
	for _, count := range []int{maximumProfileChainLength, maximumProfileChainLength + 1} {
		t.Run(fmt.Sprintf("%d profiles", count), func(t *testing.T) {
			profiles := make(map[string]*domain.ExecutionProfile, count)
			for index := 1; index <= count; index++ {
				id := fmt.Sprintf("profile-%d", index)
				definition := &domain.ExecutionProfile{ID: id}
				if index == count {
					definition.Endpoint = "https://root.example/v1"
					definition.Model = "model"
				} else {
					definition.BaseProfileID = fmt.Sprintf("profile-%d", index+1)
				}
				profiles[id] = definition
			}

			got, err := NewResolvingRepository(&resolvingTestRepository{profiles: profiles}).GetProfile(context.Background(), "profile-1")
			if count == maximumProfileChainLength {
				if err != nil || got == nil {
					t.Fatalf("profile = %+v, error = %v, want accepted chain", got, err)
				}
				return
			}
			if !errors.Is(err, ErrInvalidProfile) {
				t.Fatalf("error = %v, want ErrInvalidProfile", err)
			}
		})
	}
}

func TestResolvingRepositoryIsFreshAndCancellationAware(t *testing.T) {
	repo := &resolvingTestRepository{profiles: map[string]*domain.ExecutionProfile{
		"leaf": {ID: "leaf", BaseProfileID: "base"},
		"base": {ID: "base", Endpoint: "https://base.example/v1", Model: "first", ExtraParams: map[string]any{"nested": map[string]any{"value": "first"}}},
	}}
	resolver := NewResolvingRepository(repo)

	first, err := resolver.GetProfile(context.Background(), "leaf")
	if err != nil || first.Model != "first" {
		t.Fatalf("first result=(%+v, %v)", first, err)
	}
	repo.set("base", &domain.ExecutionProfile{ID: "base", Endpoint: "https://base.example/v1", Model: "second", ExtraParams: map[string]any{"nested": map[string]any{"value": "second"}}})
	second, err := resolver.GetProfile(context.Background(), "leaf")
	if err != nil || second.Model != "second" {
		t.Fatalf("second result=(%+v, %v)", second, err)
	}

	canceled, cancel := context.WithCancel(context.Background())
	cancel()
	if _, err := resolver.GetProfile(canceled, "leaf"); !errors.Is(err, context.Canceled) {
		t.Fatalf("canceled lookup error = %v", err)
	}
	if got := repo.callCount("leaf"); got != 2 {
		t.Fatalf("calls after canceled lookup = %d, want 2", got)
	}

	duringTraversal, cancelDuringTraversal := context.WithCancel(context.Background())
	repo.afterGet = func(id string) {
		if id == "leaf" {
			cancelDuringTraversal()
		}
	}
	if _, err := resolver.GetProfile(duringTraversal, "leaf"); !errors.Is(err, context.Canceled) {
		t.Fatalf("during traversal error = %v", err)
	}
	if got := repo.callCount("base"); got != 2 {
		t.Fatalf("base calls after cancellation = %d, want 2", got)
	}

	terminalLookup, cancelTerminalLookup := context.WithCancel(context.Background())
	repo.afterGet = func(id string) {
		if id == "base" {
			cancelTerminalLookup()
		}
	}
	if _, err := resolver.GetProfile(terminalLookup, "leaf"); !errors.Is(err, context.Canceled) {
		t.Fatalf("terminal lookup cancellation error = %v", err)
	}
	if got := repo.callCount("base"); got != 3 {
		t.Fatalf("base calls after terminal cancellation = %d, want 3", got)
	}

	repo.afterGet = nil
	var wg sync.WaitGroup
	errors := make(chan error, 8)
	for index := 0; index < cap(errors); index++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			resolved, err := resolver.GetProfile(context.Background(), "leaf")
			if err != nil {
				errors <- err
				return
			}
			resolved.ExtraParams["nested"].(map[string]any)["value"] = "mutated"
		}()
	}
	wg.Wait()
	close(errors)
	for err := range errors {
		t.Errorf("concurrent resolution: %v", err)
	}
	latest, err := resolver.GetProfile(context.Background(), "leaf")
	if err != nil || latest.ExtraParams["nested"].(map[string]any)["value"] != "second" {
		t.Fatalf("latest result=(%+v, %v)", latest, err)
	}
}

type resolvingTestRepository struct {
	mu       sync.Mutex
	profiles map[string]*domain.ExecutionProfile
	errors   map[string]error
	calls    map[string]int
	afterGet func(string)
}

func (r *resolvingTestRepository) GetProfile(ctx context.Context, id string) (*domain.ExecutionProfile, error) {
	if err := ctx.Err(); err != nil {
		return nil, err
	}
	r.mu.Lock()
	if r.calls == nil {
		r.calls = make(map[string]int)
	}
	r.calls[id]++
	err := r.errors[id]
	profile := r.profiles[id]
	afterGet := r.afterGet
	r.mu.Unlock()
	if afterGet != nil {
		afterGet(id)
	}
	if err != nil {
		return nil, err
	}
	if profile == nil {
		if _, exists := r.profiles[id]; exists {
			return nil, nil
		}
		return nil, ErrProfileNotFound
	}
	copy := *profile
	return &copy, nil
}

func (r *resolvingTestRepository) set(id string, profile *domain.ExecutionProfile) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.profiles[id] = profile
}

func (r *resolvingTestRepository) callCount(id string) int {
	r.mu.Lock()
	defer r.mu.Unlock()
	return r.calls[id]
}

func profileTestFS(files map[string]string) fs.FS {
	fsys := make(fstest.MapFS, len(files))
	for name, content := range files {
		fsys[name] = profileMapFile(content)
	}
	return fsys
}