package dbml

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

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

func readDBMLString(t *testing.T, content string) *models.Database {
	t.Helper()
	path := filepath.Join(t.TempDir(), "in.dbml")
	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
		t.Fatalf("write fixture: %v", err)
	}
	db, err := NewReader(&readers.ReaderOptions{FilePath: path}).ReadDatabase()
	if err != nil {
		t.Fatalf("ReadDatabase() error = %v", err)
	}
	return db
}

func findTable(db *models.Database, schema, table string) *models.Table {
	for _, s := range db.Schemas {
		if s.Name != schema {
			continue
		}
		for _, t := range s.Tables {
			if t.Name == table {
				return t
			}
		}
	}
	return nil
}

func fkOn(table *models.Table, col string) *models.Constraint {
	for _, c := range table.Constraints {
		if c.Type == models.ForeignKeyConstraint && len(c.Columns) == 1 && c.Columns[0] == col {
			return c
		}
	}
	return nil
}

func relFor(table *models.Table, fkName string) *models.Relationship {
	for _, r := range table.Relationships {
		if r.ForeignKey == fkName {
			return r
		}
	}
	return nil
}

func TestCommentedRef(t *testing.T) {
	tests := []struct {
		line string
		want string
		ok   bool
	}{
		{`// Ref: a.b.c > d.e.f`, `a.b.c > d.e.f`, true},
		{`// ref: a.b.c - d.e.f`, `a.b.c - d.e.f`, true},
		{`//Ref:a.b.c > d.e.f`, `a.b.c > d.e.f`, true},
		{`// Reference notes`, "", false},
		{`// see Ref: a.b.c > d.e.f`, "", false},
		{`// Ref:`, "", false},
	}
	for _, tt := range tests {
		got, ok := commentedRef(tt.line)
		if ok != tt.ok || got != tt.want {
			t.Errorf("commentedRef(%q) = (%q, %v), want (%q, %v)", tt.line, got, ok, tt.want, tt.ok)
		}
	}
}

// A commented ref whose tables are in the same file resolves on read.
func TestReader_CommentedRefSameFile(t *testing.T) {
	db := readDBMLString(t, `Table "org"."department" {
  "id_department" bigserial [pk]
}
Table "entity"."employee" {
  "id_employee" bigserial [pk]
  "rid_department" bigint
}
// Ref: "entity"."employee"."rid_department" > "org"."department"."id_department" [delete: restrict, update: restrict]
`)
	emp := findTable(db, "entity", "employee")
	fk := fkOn(emp, "rid_department")
	if fk == nil {
		t.Fatal("expected FK on rid_department")
	}
	if fk.ReferencedSchema != "org" || fk.ReferencedTable != "department" || fk.ReferencedColumns[0] != "id_department" {
		t.Errorf("FK target = %s.%s.%v", fk.ReferencedSchema, fk.ReferencedTable, fk.ReferencedColumns)
	}
	if fk.OnDelete != "restrict" || fk.OnUpdate != "restrict" {
		t.Errorf("FK actions = %q/%q, want restrict/restrict", fk.OnDelete, fk.OnUpdate)
	}
	if relFor(emp, fk.Name) == nil {
		t.Error("expected relationship for FK")
	}
	if refs := PendingCommentedRefs(db); len(refs) != 0 {
		t.Errorf("pending = %v, want none", refs)
	}
}

// A cross-file commented ref stays pending after a single-file read.
func TestReader_CommentedRefCrossFilePending(t *testing.T) {
	db := readDBMLString(t, `Table "entity"."employee" {
  "id_employee" bigserial [pk]
  "rid_department" bigint
}
// Ref: "entity"."employee"."rid_department" > "org"."department"."id_department"
`)
	if fk := fkOn(findTable(db, "entity", "employee"), "rid_department"); fk != nil {
		t.Fatal("FK must not resolve without the target table")
	}
	if refs := PendingCommentedRefs(db); len(refs) != 1 {
		t.Fatalf("pending = %v, want 1", refs)
	}
}

// Directory reads resolve commented refs after all files are merged.
func TestReader_CommentedRefDirectory(t *testing.T) {
	db, err := NewReader(&readers.ReaderOptions{
		FilePath: filepath.Join("..", "..", "..", "tests", "assets", "dbml", "multifile"),
	}).ReadDatabase()
	if err != nil {
		t.Fatalf("ReadDatabase() error = %v", err)
	}
	fk := fkOn(findTable(db, "public", "posts"), "user_id")
	if fk == nil {
		t.Fatal("expected FK posts.user_id from 9_refs.dbml commented ref")
	}
	if fk.ReferencedTable != "users" || fk.OnDelete != "CASCADE" {
		t.Errorf("FK = %s ondelete %s, want users ondelete CASCADE", fk.ReferencedTable, fk.OnDelete)
	}
}

func crossFileDB(t *testing.T, refs ...string) *models.Database {
	t.Helper()
	db := readDBMLString(t, `Table "org"."department" {
  "id_department" bigserial [pk]
}
Table "entity"."employee" {
  "id_employee" bigserial [pk]
  "rid_department" bigint
  "rid_manager" integer
  "rid_team" bigint
}
`)
	setPendingCommentedRefs(db, refs)
	return db
}

func TestResolveCommentedRefs(t *testing.T) {
	t.Run("lowercase ref and one-to-one", func(t *testing.T) {
		db := crossFileDB(t,
			`"entity"."employee"."rid_department" > "org"."department"."id_department"`,
			`entity.employee.rid_team - org.department.id_department`,
		)
		if w := ResolveCommentedRefs(db, true); len(w) != 0 {
			t.Errorf("warnings = %v, want none", w)
		}
		emp := findTable(db, "entity", "employee")
		for _, col := range []string{"rid_department", "rid_team"} {
			fk := fkOn(emp, col)
			if fk == nil {
				t.Fatalf("expected FK on %s", col)
			}
			if relFor(emp, fk.Name) == nil {
				t.Errorf("expected relationship for %s", fk.Name)
			}
		}
		if len(emp.Relationships) != 2 {
			t.Errorf("relationships = %d, want 2 (same target must not overwrite)", len(emp.Relationships))
		}
	})

	t.Run("type mismatch warns but resolves", func(t *testing.T) {
		db := crossFileDB(t, `entity.employee.rid_manager > org.department.id_department`)
		w := ResolveCommentedRefs(db, true)
		if len(w) != 1 || !strings.Contains(w[0], "type mismatch") {
			t.Errorf("warnings = %v, want one type mismatch", w)
		}
		if fkOn(findTable(db, "entity", "employee"), "rid_manager") == nil {
			t.Error("expected FK on rid_manager")
		}
	})

	t.Run("missing target stays pending until final", func(t *testing.T) {
		db := crossFileDB(t, `entity.employee.rid_team > hr.team.id_team`)
		if w := ResolveCommentedRefs(db, false); len(w) != 0 {
			t.Errorf("non-final warnings = %v, want none", w)
		}
		if len(PendingCommentedRefs(db)) != 1 {
			t.Fatal("ref should stay pending")
		}
		w := ResolveCommentedRefs(db, true)
		if len(w) != 1 || !strings.Contains(w[0], "table hr.team not found") {
			t.Errorf("final warnings = %v, want missing table", w)
		}
		if len(PendingCommentedRefs(db)) != 0 {
			t.Error("final pass must clear pending refs")
		}
	})

	t.Run("missing column", func(t *testing.T) {
		db := crossFileDB(t, `entity.employee.rid_nope > org.department.id_department`)
		w := ResolveCommentedRefs(db, true)
		if len(w) != 1 || !strings.Contains(w[0], "column entity.employee.rid_nope not found") {
			t.Errorf("warnings = %v, want missing column", w)
		}
	})

	t.Run("deduplicates against uncommented ref", func(t *testing.T) {
		db := readDBMLString(t, `Table "org"."department" {
  "id_department" bigserial [pk]
}
Table "entity"."employee" {
  "id_employee" bigserial [pk]
  "rid_department" bigint
}
Ref: "entity"."employee"."rid_department" > "org"."department"."id_department"
// Ref: "entity"."employee"."rid_department" > "org"."department"."id_department"
`)
		emp := findTable(db, "entity", "employee")
		count := 0
		for _, c := range emp.Constraints {
			if c.Type == models.ForeignKeyConstraint {
				count++
			}
		}
		if count != 1 || len(emp.Relationships) != 1 {
			t.Errorf("FKs = %d, relationships = %d, want 1 and 1", count, len(emp.Relationships))
		}
	})
}

func TestCompatibleFKTypes(t *testing.T) {
	tests := []struct {
		a, b string
		want bool
	}{
		{"bigint", "bigserial", true},
		{"integer", "serial", true},
		{"INT4", "integer", true},
		{"varchar(10)", "varchar(20)", true},
		{"bigint", "serial", false},
		{"uuid", "bigint", false},
		{"", "bigint", true},
	}
	for _, tt := range tests {
		if got := compatibleFKTypes(tt.a, tt.b); got != tt.want {
			t.Errorf("compatibleFKTypes(%q, %q) = %v, want %v", tt.a, tt.b, got, tt.want)
		}
	}
}