package validation

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"gitea.maximumdirect.net/eric/ReleaseKit/internal/git"
)

func TestCheckFileSizeUsesStrictLimitsAndDefault(t *testing.T) {
	tests := []struct {
		name      string
		limit     *int64
		size      int64
		wantLimit int64
		wantError bool
	}{
		{name: "below", limit: int64Pointer(10), size: 9, wantLimit: 10},
		{name: "at", limit: int64Pointer(10), size: 10, wantLimit: 10},
		{name: "above", limit: int64Pointer(10), size: 11, wantLimit: 10, wantError: true},
		{name: "default at", size: 1_000_000, wantLimit: 1_000_000},
		{name: "default above", size: 1_000_001, wantLimit: 1_000_000, wantError: true},
		{name: "zero empty", limit: int64Pointer(0), size: 0},
		{name: "zero nonempty", limit: int64Pointer(0), size: 1, wantError: true},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			entries := []git.TreeEntry{{
				Path: "file.bin", Type: "blob", Mode: "100644", Size: test.size, HasSize: true,
			}}
			tree := &CandidateTree{entries: entries, inputEntries: entries}
			err := checkFileSize(tree, &FileSizeSettings{LimitBytes: test.limit})
			if !test.wantError {
				if err != nil {
					t.Fatalf("checkFileSize() error = %v, want nil", err)
				}
				return
			}
			failure, ok := err.(*Failure)
			if !ok || failure.Check != FileSize || len(failure.Findings) != 1 || failure.Findings[0].Path != "file.bin" {
				t.Fatalf("checkFileSize() error = %v, want file-size finding", err)
			}
			if failure.Measurement == nil || failure.Measurement.Bytes != test.size || failure.Measurement.LimitBytes != test.wantLimit {
				t.Fatalf("measurement = %#v, want %d bytes against %d", failure.Measurement, test.size, test.wantLimit)
			}
		})
	}
}

func TestCheckFileSizeAppliesLiteralPathExclusions(t *testing.T) {
	tests := []struct {
		name       string
		entries    []git.TreeEntry
		exclusions []string
		wantPath   string
	}{
		{
			name: "directory boundary and normalized paths",
			entries: []git.TreeEntry{
				{Path: "assets/icon.png", Type: "blob", Size: 20, HasSize: true},
				{Path: "assets-other/icon.png", Type: "blob", Size: 20, HasSize: true},
			},
			exclusions: []string{"./assets/"},
			wantPath:   "assets-other/icon.png",
		},
		{
			name: "glob metacharacters are literal",
			entries: []git.TreeEntry{
				{Path: "[ab].dat", Type: "blob", Size: 20, HasSize: true},
				{Path: "a.dat", Type: "blob", Size: 20, HasSize: true},
			},
			exclusions: []string{"[ab].dat", "literal[set]"},
			wantPath:   "a.dat",
		},
		{
			name: "directory metacharacters are literal",
			entries: []git.TreeEntry{
				{Path: "literal[set]/file.dat", Type: "blob", Size: 20, HasSize: true},
				{Path: "literalx/file.dat", Type: "blob", Size: 20, HasSize: true},
			},
			exclusions: []string{"literal[set]"},
			wantPath:   "literalx/file.dat",
		},
		{
			name: "unmatched exclusion",
			entries: []git.TreeEntry{
				{Path: "selected.dat", Type: "blob", Size: 20, HasSize: true},
			},
			exclusions: []string{"not-present"},
			wantPath:   "selected.dat",
		},
		{
			name: "exact file exclusion",
			entries: []git.TreeEntry{
				{Path: "selected.dat", Type: "blob", Size: 20, HasSize: true},
				{Path: "other.dat", Type: "blob", Size: 20, HasSize: true},
			},
			exclusions: []string{"selected.dat"},
			wantPath:   "other.dat",
		},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			settings := fileSizeSettingsForModule(&FileSizeSettings{
				LimitBytes: int64Pointer(10),
				Exclusions: test.exclusions,
			}, ".")
			err := checkFileSize(&CandidateTree{entries: test.entries, inputEntries: test.entries}, settings)
			failure, ok := err.(*Failure)
			if !ok || failure.Check != FileSize || len(failure.Findings) != 1 || failure.Findings[0].Path != test.wantPath {
				t.Fatalf("checkFileSize() error = %v, want only %q to exceed the limit", err, test.wantPath)
			}
		})
	}
}

func TestCheckFileSizeUsesCommittedBlobSizes(t *testing.T) {
	repository := newTreeRepository(t)
	writeTreeFile(t, repository, "small.bin", []byte{0, 1})
	writeTreeFile(t, repository, "boundary.bin", []byte{0, 1, 2})
	if err := os.Symlink("small.bin", filepath.Join(repository, "link")); err != nil {
		t.Fatal(err)
	}
	submodule := newTreeRepository(t)
	writeTreeFile(t, submodule, "submodule.txt", []byte("submodule"))
	gitTree(t, submodule, "add", "--all")
	gitTree(t, submodule, "commit", "-m", "create nested source")
	submoduleCommit := strings.TrimSpace(gitTree(t, submodule, "rev-parse", "HEAD"))
	gitTree(t, repository, "add", "--all")
	gitTree(t, repository, "update-index", "--add", "--cacheinfo", "160000,"+submoduleCommit+",submodule")
	commit := commitCandidateTree(t, repository)
	tree, err := ReadCandidateTree(context.Background(), repository, commit)
	if err != nil {
		t.Fatal(err)
	}
	cleanupCandidateTree(t, tree)

	err = checkFileSize(tree, &FileSizeSettings{LimitBytes: int64Pointer(3), Exclusions: []string{"link"}})
	if err != nil {
		t.Fatalf("checkFileSize() error = %v, want small binary and exact-limit blob to pass", err)
	}

	err = checkFileSize(tree, &FileSizeSettings{LimitBytes: int64Pointer(3), Exclusions: []string{"small.bin", "boundary.bin"}})
	failure, ok := err.(*Failure)
	if !ok || failure.Check != FileSize || len(failure.Findings) != 1 || failure.Findings[0].Path != "link" {
		t.Fatalf("checkFileSize() error = %v, want symlink blob to exceed the limit", err)
	}
	if failure.Measurement == nil || failure.Measurement.Bytes != int64(len("small.bin")) {
		t.Fatalf("symlink measurement = %#v, want link-text size %d", failure.Measurement, len("small.bin"))
	}

	err = checkFileSize(tree, &FileSizeSettings{LimitBytes: int64Pointer(0), Exclusions: []string{"small.bin", "boundary.bin", "link"}})
	if err != nil {
		t.Fatalf("checkFileSize() error = %v, want omitted gitlink size", err)
	}
}

func TestCheckFileSizeUsesOnlyCandidateFilesIndividually(t *testing.T) {
	repository := newTreeRepository(t)
	writeTreeFile(t, repository, "historical-large.dat", []byte(strings.Repeat("h", 20)))
	commitCandidateTree(t, repository)
	if err := os.Remove(filepath.Join(repository, "historical-large.dat")); err != nil {
		t.Fatal(err)
	}
	writeTreeFile(t, repository, "one.dat", []byte(strings.Repeat("a", 6)))
	writeTreeFile(t, repository, "two.dat", []byte(strings.Repeat("b", 6)))
	commit := commitCandidateTree(t, repository)
	tree, err := ReadCandidateTree(context.Background(), repository, commit)
	if err != nil {
		t.Fatal(err)
	}
	cleanupCandidateTree(t, tree)
	if err := checkFileSize(tree, &FileSizeSettings{LimitBytes: int64Pointer(10)}); err != nil {
		t.Fatalf("checkFileSize() error = %v, want current individual files to pass", err)
	}
}

func TestRunRejectsNegativeFileSizeLimitBeforeGoChecks(t *testing.T) {
	negative := int64(-1)
	err := Run(context.Background(), Request{Settings: Settings{
		FileSize: &FileSizeSettings{LimitBytes: &negative},
	}})
	failure, ok := err.(*Failure)
	if !ok || failure.Check != FileSize || len(failure.Findings) != 1 || !strings.Contains(failure.Findings[0].Message, "negative") {
		t.Fatalf("Run() error = %v, want invalid file-size limit failure", err)
	}
	if errors.Unwrap(failure) != nil {
		t.Fatalf("invalid limit failure cause = %v, want none", failure.Cause)
	}
}

func int64Pointer(value int64) *int64 { return &value }