package pgsql

import (
	"strings"
	"testing"

	"git.warky.dev/wdevs/relspecgo/pkg/models"
	"git.warky.dev/wdevs/relspecgo/pkg/writers"
)

// diffTestDB builds a database with one table per spec: name -> column name -> type.
func diffTestDB(schemaName string, tables map[string]map[string]string) *models.Database {
	db := models.InitDatabase("testdb")
	schema := models.InitSchema(schemaName)
	for tName, cols := range tables {
		table := models.InitTable(tName, schemaName)
		seq := 1
		for cName, cType := range cols {
			col := models.InitColumn(cName, tName, schemaName)
			col.Type = cType
			col.Sequence = uint(seq)
			seq++
			table.Columns[cName] = col
		}
		schema.Tables = append(schema.Tables, table)
	}
	db.Schemas = append(db.Schemas, schema)
	return db
}

func diffJoin(stmts []string) string { return strings.Join(stmts, "\n") }

func TestDiffStatements(t *testing.T) {
	tests := []struct {
		name        string
		model       func() *models.Database
		current     func() *models.Database
		wantContain []string
		wantAbsent  []string
		wantEmpty   bool
	}{
		{
			name: "identical schemas produce no statements",
			model: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "email": "text"}})
			},
			current: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "email": "text"}})
			},
			wantEmpty: true,
		},
		{
			name: "missing table is created",
			model: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer"}, "posts": {"id": "integer"}})
			},
			current: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer"}})
			},
			wantContain: []string{"CREATE TABLE IF NOT EXISTS public.posts"},
			wantAbsent:  []string{"public.users"},
		},
		{
			name: "missing column is added and existing columns are skipped",
			model: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "email": "text"}})
			},
			current: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer"}})
			},
			wantContain: []string{"ADD COLUMN IF NOT EXISTS email text"},
			wantAbsent:  []string{"COLUMN id"},
		},
		{
			name: "changed column type is altered",
			model: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "bigint"}})
			},
			current: func() *models.Database {
				return diffTestDB("public", map[string]map[string]string{"users": {"id": "integer"}})
			},
			wantContain: []string{"ALTER COLUMN id TYPE bigint"},
		},
		{
			name: "missing non-public schema is created before its tables",
			model: func() *models.Database {
				return diffTestDB("app", map[string]map[string]string{"users": {"id": "integer"}})
			},
			current: func() *models.Database { return models.InitDatabase("testdb") },
			wantContain: []string{
				"CREATE SCHEMA IF NOT EXISTS app",
				"CREATE TABLE IF NOT EXISTS app.users",
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			w := NewWriter(&writers.WriterOptions{})
			stmts, err := w.diffStatements(tt.model(), tt.current())
			if err != nil {
				t.Fatalf("diffStatements failed: %v", err)
			}
			out := diffJoin(stmts)

			if tt.wantEmpty && len(stmts) != 0 {
				t.Fatalf("expected no statements, got:\n%s", out)
			}
			for _, want := range tt.wantContain {
				if !strings.Contains(out, want) {
					t.Errorf("missing %q in:\n%s", want, out)
				}
			}
			for _, absent := range tt.wantAbsent {
				if strings.Contains(out, absent) {
					t.Errorf("unexpected %q in:\n%s", absent, out)
				}
			}
		})
	}
}

func TestDiffStatements_SchemaCreatedBeforeTables(t *testing.T) {
	w := NewWriter(&writers.WriterOptions{})
	model := diffTestDB("app", map[string]map[string]string{"users": {"id": "integer"}})
	stmts, err := w.diffStatements(model, models.InitDatabase("testdb"))
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}

	schemaIdx, tableIdx := -1, -1
	for i, s := range stmts {
		if strings.Contains(s, "CREATE SCHEMA") {
			schemaIdx = i
		}
		if strings.Contains(s, "CREATE TABLE") {
			tableIdx = i
		}
	}
	if schemaIdx < 0 || tableIdx < 0 || schemaIdx > tableIdx {
		t.Fatalf("expected CREATE SCHEMA before CREATE TABLE, got:\n%s", diffJoin(stmts))
	}
}

func TestDiffStatements_NewTableCreatesPrimaryKeySequence(t *testing.T) {
	model := models.InitDatabase("testdb")
	schema := models.InitSchema("public")
	table := models.InitTable("users", "public")
	id := models.InitColumn("id", "users", "public")
	id.Type = "integer"
	id.IsPrimaryKey = true
	id.Default = "nextval('public.users_id_seq'::regclass)"
	table.Columns["id"] = id
	schema.Tables = append(schema.Tables, table)
	model.Schemas = append(model.Schemas, schema)

	w := NewWriter(&writers.WriterOptions{})
	stmts, err := w.diffStatements(model, models.InitDatabase("testdb"))
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	out := diffJoin(stmts)
	if !strings.Contains(out, "CREATE SEQUENCE IF NOT EXISTS public.users_id_seq") {
		t.Fatalf("expected sequence creation, got:\n%s", out)
	}

	// Existing table: sequence must not be re-emitted.
	current := models.InitDatabase("testdb")
	cs := models.InitSchema("public")
	cs.Tables = append(cs.Tables, table)
	current.Schemas = append(current.Schemas, cs)
	stmts, err = w.diffStatements(model, current)
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if strings.Contains(diffJoin(stmts), "CREATE SEQUENCE") {
		t.Fatalf("sequence emitted for existing table:\n%s", diffJoin(stmts))
	}
}

func TestDiffStatements_NewIndexAndChangedIndexRecreated(t *testing.T) {
	build := func(cols ...string) *models.Database {
		db := diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "email": "text", "name": "text"}})
		table := db.Schemas[0].Tables[0]
		table.Indexes["idx_users_lookup"] = &models.Index{Name: "idx_users_lookup", Columns: cols}
		return db
	}
	w := NewWriter(&writers.WriterOptions{})

	// Index missing in current.
	noIdx := diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "email": "text", "name": "text"}})
	stmts, err := w.diffStatements(build("email"), noIdx)
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if !strings.Contains(diffJoin(stmts), "CREATE INDEX IF NOT EXISTS idx_users_lookup") {
		t.Fatalf("expected index creation, got:\n%s", diffJoin(stmts))
	}

	// Index unchanged.
	stmts, err = w.diffStatements(build("email"), build("email"))
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if len(stmts) != 0 {
		t.Fatalf("expected no statements for identical index, got:\n%s", diffJoin(stmts))
	}

	// Index definition changed: dropped and recreated.
	stmts, err = w.diffStatements(build("name"), build("email"))
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	out := diffJoin(stmts)
	dropIdx := strings.Index(out, "DROP INDEX")
	createIdx := strings.Index(out, "CREATE INDEX")
	if dropIdx < 0 || createIdx < 0 || dropIdx > createIdx {
		t.Fatalf("expected DROP INDEX before CREATE INDEX, got:\n%s", out)
	}
}

func TestDiffStatements_FlattenSchemaRejected(t *testing.T) {
	w := NewWriter(&writers.WriterOptions{FlattenSchema: true})
	if _, err := w.generateLiveDiffStatements(models.InitDatabase("x"), "postgres://unused"); err == nil {
		t.Fatal("expected error so the caller falls back to full DDL")
	}
}

func TestDiffStatements_LiveDatabaseRepresentationsAreNotDifferences(t *testing.T) {
	build := func(live bool) *models.Database {
		db := models.InitDatabase("testdb")
		schema := models.InitSchema("public")

		parent := models.InitTable("parent", "public")
		parentID := models.InitColumn("id_parent", "parent", "public")
		parentCurrentType := "bigserial"
		if live {
			parentCurrentType = "bigint"
		}
		parentID.Type = parentCurrentType
		parentID.IsPrimaryKey = true
		parentID.NotNull = true
		parent.Columns["id_parent"] = parentID
		if live {
			// A live database reports the PK as a named constraint and the unique
			// constraint's backing index as an index too.
			parent.Constraints["pk_public_parent"] = &models.Constraint{
				Name: "pk_public_parent", Type: models.PrimaryKeyConstraint, Columns: []string{"id_parent"},
			}
		}
		guid := models.InitColumn("guid", "parent", "public")
		guid.Type = "uuid"
		parent.Columns["guid"] = guid
		parent.Constraints["ukey_parent_guid"] = &models.Constraint{
			Name: "ukey_parent_guid", Type: models.UniqueConstraint, Columns: []string{"guid"},
		}
		if live {
			parent.Indexes["ukey_parent_guid"] = &models.Index{Name: "ukey_parent_guid", Unique: true, Columns: []string{"guid"}, Type: "btree"}
		}

		// numeric(10,0) vs numeric(10); quoted default vs unquoted default with cast.
		amount := models.InitColumn("amount", "parent", "public")
		amount.Type = "numeric(10,0)"
		tags := models.InitColumn("tags", "parent", "public")
		tags.Type = "jsonb"
		tags.Default = "`'[]'`"
		if live {
			amount.Type = "numeric"
			amount.Precision = 10
			tags.Default = "[]"
		}
		parent.Columns["amount"] = amount
		parent.Columns["tags"] = tags

		parent.Indexes["idx_parent_amount"] = &models.Index{Name: "idx_parent_amount", Columns: []string{"amount"}}
		if live {
			parent.Indexes["idx_parent_amount"].Type = "btree"
		}

		child := models.InitTable("child", "public")
		cid := models.InitColumn("id_child", "child", "public")
		cid.Type = "integer"
		child.Columns["id_child"] = cid
		rid := models.InitColumn("rid_parent", "child", "public")
		rid.Type = "bigint"
		child.Columns["rid_parent"] = rid
		action := "restrict"
		if live {
			action = "RESTRICT"
		}
		child.Constraints["fk_child_rid_parent"] = &models.Constraint{
			Name: "fk_child_rid_parent", Type: models.ForeignKeyConstraint, Columns: []string{"rid_parent"},
			ReferencedTable: "parent", ReferencedSchema: "public", ReferencedColumns: []string{"id_parent"},
			OnDelete: action, OnUpdate: action,
		}

		parent.Description = "Parent\ntable"
		if live {
			parent.Description = "Parent\ntable\n"
		}

		schema.Tables = append(schema.Tables, parent, child)
		db.Schemas = append(db.Schemas, schema)
		return db
	}

	w := NewWriter(&writers.WriterOptions{})
	stmts, err := w.diffStatements(build(false), build(true))
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if len(stmts) != 0 {
		t.Fatalf("expected live representations to match the model, got:\n%s", diffJoin(stmts))
	}
}

func TestDiffStatements_ChangedPrimaryKeyIsRecreated(t *testing.T) {
	model := diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "tenant": "integer"}})
	model.Schemas[0].Tables[0].Columns["tenant"].IsPrimaryKey = true

	current := diffTestDB("public", map[string]map[string]string{"users": {"id": "integer", "tenant": "integer"}})
	current.Schemas[0].Tables[0].Columns["id"].IsPrimaryKey = true
	current.Schemas[0].Tables[0].Constraints["pk_public_users"] = &models.Constraint{
		Name: "pk_public_users", Type: models.PrimaryKeyConstraint, Columns: []string{"id"},
	}

	w := NewWriter(&writers.WriterOptions{})
	stmts, err := w.diffStatements(model, current)
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if !strings.Contains(diffJoin(stmts), "DROP CONSTRAINT IF EXISTS pk_public_users") {
		t.Fatalf("expected old primary key to be dropped, got:\n%s", diffJoin(stmts))
	}
}

func TestDiffStatements_ChangedCommentEmitted(t *testing.T) {
	model := diffTestDB("public", map[string]map[string]string{"users": {"id": "integer"}})
	model.Schemas[0].Tables[0].Description = "new"
	current := diffTestDB("public", map[string]map[string]string{"users": {"id": "integer"}})
	current.Schemas[0].Tables[0].Description = "old"

	w := NewWriter(&writers.WriterOptions{})
	stmts, err := w.diffStatements(model, current)
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if !strings.Contains(diffJoin(stmts), "COMMENT ON TABLE public.users IS 'new'") {
		t.Fatalf("expected changed comment, got:\n%s", diffJoin(stmts))
	}
}

func TestDiffStatements_TruncatedConstraintNameMatches(t *testing.T) {
	long := "fk_individual_actor_relationship_rid_typelookup_relationship_type"
	if len(long) <= maxIdentifierBytes {
		t.Fatal("test name must exceed the identifier limit")
	}
	build := func(name string) *models.Database {
		db := diffTestDB("public", map[string]map[string]string{
			"parent": {"id": "integer"},
			"child":  {"rid": "integer"},
		})
		for _, tbl := range db.Schemas[0].Tables {
			if tbl.Name == "child" {
				tbl.Constraints[name] = &models.Constraint{
					Name: name, Type: models.ForeignKeyConstraint, Columns: []string{"rid"},
					ReferencedTable: "parent", ReferencedSchema: "public", ReferencedColumns: []string{"id"},
				}
			}
		}
		return db
	}

	w := NewWriter(&writers.WriterOptions{})
	stmts, err := w.diffStatements(build(long), build(pgIdentifier(long)))
	if err != nil {
		t.Fatalf("diffStatements failed: %v", err)
	}
	if len(stmts) != 0 {
		t.Fatalf("expected truncated live name to match, got:\n%s", diffJoin(stmts))
	}
}

func TestColumnDefaultsEqual_LiveRepresentations(t *testing.T) {
	tests := []struct {
		name       string
		model, cur interface{}
		want       bool
	}{
		{"cast wrapped in parentheses", "gen_random_uuid()::text", "(gen_random_uuid())::text", true},
		{"jsonb re-spaced array", `'["openid","profile","email"]'`, `'["openid", "profile", "email"]'::jsonb`, true},
		{"backticked function", "`now()`", "now()", true},
		{"quoted literal with cast", "'[]'", "'[]'::jsonb", true},
		{"jsonb array already unquoted by the reader", `'["openid","profile"]'`, `["openid", "profile"]`, true},
		{"text with spaces and braces", "`'{actor} #{actor_id} - {chartofaccount}'`", "{actor} #{actor_id} - {chartofaccount}", true},
		{"cast on plain function stays equal", "gen_random_uuid()::text", "gen_random_uuid()::text", true},
		{"different jsonb content", `'["a"]'`, `'["b"]'::jsonb`, false},
		{"different function", "gen_random_uuid()::text", "(now())::text", false},
		{"different literal", "'active'", "'inactive'::text", false},
		{"nil vs value", nil, "now()", false},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := columnDefaultsEqual(tt.model, tt.cur); got != tt.want {
				t.Errorf("columnDefaultsEqual(%v, %v) = %v, want %v", tt.model, tt.cur, got, tt.want)
			}
		})
	}
}