package utils

import (
	"reflect"
	"testing"

	"bookhoard/internal/database"

	"github.com/jackc/pgx/v5/pgtype"
)

func TestMergeOverrides(t *testing.T) {
	got := MergeOverrides([]string{"title", "tags"}, "tags", "description", "")
	want := []string{"title", "tags", "description"}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("MergeOverrides() = %v, want %v", got, want)
	}
	if MergeOverrides(nil) == nil {
		t.Error("MergeOverrides(nil) must return non-nil slice")
	}
}

func TestDetectMetadataOverrides(t *testing.T) {
	existing := database.MediaItems{
		Title:       "Scanned Title",
		Description: pgtype.Text{String: "Scanned description", Valid: true},
		Tags:        []string{"foo", "bar"},
	}
	params := database.UpdateMediaItemParams{
		// unchanged
		Title: "Scanned Title",
		// changed
		Description: pgtype.Text{String: "My custom description", Valid: true},
		Tags:        []string{"foo", "bar"},
	}

	got := DetectMetadataOverrides(params, existing)
	if !reflect.DeepEqual(got, []string{"description"}) {
		t.Errorf("DetectMetadataOverrides() = %v, want [description]", got)
	}

	// Overrides accumulate: an existing override survives a later save.
	existing.MetadataOverrides = []string{"publisher"}
	got = DetectMetadataOverrides(params, existing)
	want := []string{"publisher", "description"}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("DetectMetadataOverrides() accumulate = %v, want %v", got, want)
	}

	// An untouched save detects nothing new.
	noop := database.UpdateMediaItemParams{
		Title:       existing.Title,
		Description: existing.Description,
		Tags:        existing.Tags,
	}
	got = DetectMetadataOverrides(noop, existing)
	if !reflect.DeepEqual(got, []string{"publisher"}) {
		t.Errorf("DetectMetadataOverrides() noop = %v, want [publisher]", got)
	}
}

func TestDetectMetadataOverridesUnsetFormsEqual(t *testing.T) {
	// Zero-value params must not look "changed" against NULL-ish columns.
	existing := database.MediaItems{
		PageCount:       pgtype.Int4{Int32: 0, Valid: false},
		SeriesNumber:    pgtype.Int4{Int32: 5, Valid: true},
		CommunityRating: pgtype.Float8{Float64: 0, Valid: false},
	}
	params := database.UpdateMediaItemParams{
		PageCount:       pgtype.Int4{Int32: 0, Valid: false},
		SeriesNumber:    pgtype.Int4{Int32: 0, Valid: false}, // cleared by user -> changed
		CommunityRating: pgtype.Float8{Float64: 0, Valid: false},
	}
	got := DetectMetadataOverrides(params, existing)
	if !reflect.DeepEqual(got, []string{"series_number"}) {
		t.Errorf("DetectMetadataOverrides() = %v, want [series_number]", got)
	}
}

func TestApplyMetadataOverrides(t *testing.T) {
	existing := database.MediaItems{
		Title:          "Custom Title",
		Description:    pgtype.Text{String: "Custom desc", Valid: true},
		Tags:           []string{"mine"},
		TagsSearch:     []string{"mine"},
		CoverImagePath: pgtype.Text{String: "books/x.epub.custom_cover.jpg", Valid: true},
	}
	params := database.UpdateMediaItemParams{
		Title:          "Scanned Title",
		Description:    pgtype.Text{String: "Scanned desc", Valid: true},
		Tags:           []string{"scanned"},
		TagsSearch:     []string{"scanned"},
		CoverImagePath: pgtype.Text{String: "books/x.epub.cover.jpg", Valid: true},
	}

	// Only title and tags overridden; scanned description and cover win.
	existing.MetadataOverrides = []string{"title", "tags"}
	ApplyMetadataOverrides(&params, existing)

	if params.Title != "Custom Title" {
		t.Errorf("Title = %q, want %q", params.Title, "Custom Title")
	}
	if !reflect.DeepEqual(params.Tags, []string{"mine"}) || !reflect.DeepEqual(params.TagsSearch, []string{"mine"}) {
		t.Error("Tags/TagsSearch must be restored together")
	}
	if params.Description.String != "Scanned desc" {
		t.Errorf("Description = %q, want scanned value", params.Description.String)
	}
	if params.CoverImagePath.String != "books/x.epub.cover.jpg" {
		t.Errorf("CoverImagePath = %q, want scanned value", params.CoverImagePath.String)
	}
}