package template

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

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

func writeTemplateFile(t *testing.T, body string) string {
	t.Helper()
	p := filepath.Join(t.TempDir(), "t.tmpl")
	if err := os.WriteFile(p, []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}
	return p
}

func modeDB() *models.Database {
	db := models.InitDatabase("shop")
	for _, sn := range []string{"a", "b"} {
		s := models.InitSchema(sn)
		for _, tn := range []string{"t1", "t2"} {
			s.Tables = append(s.Tables, models.InitTable(tn, sn))
		}
		s.Scripts = append(s.Scripts, &models.Script{Name: "seed_" + sn})
		db.Schemas = append(db.Schemas, s)
	}
	db.Domains = append(db.Domains, &models.Domain{Name: "billing"})
	return db
}

func newTestWriter(t *testing.T, body, mode, pattern, out string) (*Writer, error) {
	t.Helper()
	meta := map[string]interface{}{"template_path": writeTemplateFile(t, body)}
	if mode != "" {
		meta["mode"] = mode
	}
	if pattern != "" {
		meta["filename_pattern"] = pattern
	}
	return NewWriter(&writers.WriterOptions{OutputPath: out, Metadata: meta})
}

func TestNewWriterErrors(t *testing.T) {
	if _, err := NewWriter(&writers.WriterOptions{}); err == nil {
		t.Error("expected error for missing template path")
	}
	_, err := NewWriter(&writers.WriterOptions{Metadata: map[string]interface{}{"template_path": "/no/such/file"}})
	var te *TemplateError
	if !errors.As(err, &te) || te.Phase != "load" {
		t.Errorf("load error: %v", err)
	}
	_, err = newTestWriter(t, "{{ .Unclosed ", "", "", "")
	if !errors.As(err, &te) || te.Phase != "parse" {
		t.Errorf("parse error: %v", err)
	}
}

func TestWriterModes(t *testing.T) {
	tests := []struct {
		name, mode, body, pattern string
		wantFiles                 []string
	}{
		{"database", "database", "{{.Database.Name}}", "", []string{"out.txt"}},
		{"schema", "schema", "{{.Schema.Name}}", "{{.Name}}.txt", []string{"a.txt", "b.txt"}},
		{"table", "table", "{{.Table.Name}}", "{{.ParentSchema.Name}}_{{.Name}}.txt", []string{"a_t1.txt", "a_t2.txt", "b_t1.txt", "b_t2.txt"}},
		{"script", "script", "{{.Script.Name}}", "{{.Name}}.sql", []string{"seed_a.sql", "seed_b.sql"}},
		{"domain", "domain", "{{.Domain.Name}}", "{{.Name}}.md", []string{"billing.md"}},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			outDir := t.TempDir()
			out := outDir
			if tt.mode == "database" {
				out = filepath.Join(outDir, "out.txt")
			}
			w, err := newTestWriter(t, tt.body, tt.mode, tt.pattern, out)
			if err != nil {
				t.Fatal(err)
			}
			if err := w.WriteDatabase(modeDB()); err != nil {
				t.Fatal(err)
			}
			for _, f := range tt.wantFiles {
				if _, err := os.Stat(filepath.Join(outDir, f)); err != nil {
					t.Errorf("missing %s: %v", f, err)
				}
			}
			entries, _ := os.ReadDir(outDir)
			if len(entries) != len(tt.wantFiles) {
				t.Errorf("got %d files, want %d", len(entries), len(tt.wantFiles))
			}
		})
	}
}

func TestWriterDatabaseModeContent(t *testing.T) {
	out := filepath.Join(t.TempDir(), "sub", "dir", "o.txt")
	w, err := newTestWriter(t, "{{.Database.Name}}:{{len .Database.Schemas}}", "", "", out)
	if err != nil {
		t.Fatal(err)
	}
	if err := w.WriteDatabase(modeDB()); err != nil {
		t.Fatal(err)
	}
	data, err := os.ReadFile(out)
	if err != nil || string(data) != "shop:2" {
		t.Errorf("content %q err %v", data, err)
	}
}

func TestWriterUnknownMode(t *testing.T) {
	w, err := newTestWriter(t, "x", "bogus", "", "")
	if err != nil {
		t.Fatal(err)
	}
	if err := w.WriteDatabase(modeDB()); err == nil || !strings.Contains(err.Error(), "unknown entrypoint mode") {
		t.Errorf("got %v", err)
	}
}

func TestWriterExecuteErrors(t *testing.T) {
	// Execution failure: field does not exist on TemplateData.
	for _, mode := range []string{"database", "schema", "table", "script", "domain"} {
		t.Run(mode, func(t *testing.T) {
			w, err := newTestWriter(t, "{{.NoSuchField}}", mode, "", t.TempDir())
			if err != nil {
				t.Fatal(err)
			}
			err = w.WriteDatabase(modeDB())
			var te *TemplateError
			if !errors.As(err, &te) || te.Phase != "execute" {
				t.Errorf("got %v", err)
			}
		})
	}
}

func TestWriterBadFilenamePattern(t *testing.T) {
	for _, pattern := range []string{"{{.Unclosed", "{{.NoSuchField}}"} {
		for _, mode := range []string{"schema", "table", "script", "domain"} {
			w, err := newTestWriter(t, "x", mode, pattern, t.TempDir())
			if err != nil {
				t.Fatal(err)
			}
			if err := w.WriteDatabase(modeDB()); err == nil {
				t.Errorf("mode %s pattern %q: expected error", mode, pattern)
			}
		}
	}
}

func TestWriterWriteOutputFailure(t *testing.T) {
	// Output path whose parent is a regular file cannot be created.
	blocker := filepath.Join(t.TempDir(), "file")
	if err := os.WriteFile(blocker, nil, 0o644); err != nil {
		t.Fatal(err)
	}
	w, err := newTestWriter(t, "x", "database", "", filepath.Join(blocker, "child", "o.txt"))
	if err != nil {
		t.Fatal(err)
	}
	if err := w.WriteDatabase(modeDB()); err == nil {
		t.Error("expected write failure")
	}
}

func TestWriterGenerateFilenameOutputPathForms(t *testing.T) {
	dir := t.TempDir()
	data := NewTableData(models.InitTable("users", "public"), nil, nil, nil)

	tests := []struct {
		name, out, want string
	}{
		{"no output path", "", "users.txt"},
		{"existing dir", dir, filepath.Join(dir, "users.txt")},
		{"trailing separator", filepath.Join(dir, "new") + string(filepath.Separator), filepath.Join(dir, "new", "users.txt")},
		{"file path uses its dir", filepath.Join(dir, "x.out"), filepath.Join(dir, "users.txt")},
		{"bare file name", "x.out", "users.txt"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			w, err := newTestWriter(t, "x", "table", "{{.Name}}.txt", tt.out)
			if err != nil {
				t.Fatal(err)
			}
			got, err := w.generateFilename(data)
			if err != nil || got != tt.want {
				t.Errorf("got %q err %v, want %q", got, err, tt.want)
			}
		})
	}
}

func TestWriterWriteSchemaAndTable(t *testing.T) {
	out := filepath.Join(t.TempDir(), "o.txt")
	w, err := newTestWriter(t, "{{range .Database.Schemas}}{{.Name}}:{{len .Tables}};{{end}}", "", "", out)
	if err != nil {
		t.Fatal(err)
	}
	db := modeDB()
	if err := w.WriteSchema(db.Schemas[0]); err != nil {
		t.Fatal(err)
	}
	if data, _ := os.ReadFile(out); string(data) != "a:2;" {
		t.Errorf("WriteSchema: %q", data)
	}
	if err := w.WriteTable(db.Schemas[1].Tables[0]); err != nil {
		t.Fatal(err)
	}
	if data, _ := os.ReadFile(out); string(data) != "b:1;" {
		t.Errorf("WriteTable: %q", data)
	}
}