package main

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
)

type Testcase struct {
	Name       string
	Path       string
	ConfigName string
	Stderr     []byte
	Stdout     []byte
	Exec       *Exec
}

type ExecMeta struct {
	InvalidSchema bool `json:"invalid_schema"`
}

type Exec struct {
	Command  string            `json:"command"`
	Args     []string          `json:"args"`
	Contexts []string          `json:"contexts"`
	Process  string            `json:"process"`
	OS       []string          `json:"os"`
	Env      map[string]string `json:"env"`
	Meta     ExecMeta          `json:"meta"`
}

func parseStderr(t *testing.T, dir, testctx string) []byte {
	t.Helper()
	paths := []string{
		filepath.Join(dir, "stderr", fmt.Sprintf("%s.txt", testctx)),
		filepath.Join(dir, fmt.Sprintf("stderr_%s.txt", runtime.GOOS)),
		filepath.Join(dir, "stderr.txt"),
	}
	for _, path := range paths {
		if _, err := os.Stat(path); !os.IsNotExist(err) {
			blob, err := os.ReadFile(path)
			if err != nil {
				t.Fatal(err)
			}
			return blob
		}
	}
	return nil
}

// parseStdout reads the command's expected output: stdout.json for a
// command that prints JSON, so editors highlight it, otherwise stdout.txt.
func parseStdout(t *testing.T, dir string) []byte {
	t.Helper()
	for _, name := range []string{"stdout.json", "stdout.txt"} {
		path := filepath.Join(dir, name)
		if _, err := os.Stat(path); os.IsNotExist(err) {
			continue
		}
		blob, err := os.ReadFile(path)
		if err != nil {
			t.Fatal(err)
		}
		return blob
	}
	return nil
}

// hasSQLCConfig reports whether dir contains an sqlc configuration file.
func hasSQLCConfig(dir string) bool {
	for _, name := range []string{"sqlc.json", "sqlc.yaml", "sqlc.yml"} {
		if _, err := os.Stat(filepath.Join(dir, name)); err == nil {
			return true
		}
	}
	return false
}

func parseExec(t *testing.T, dir string) *Exec {
	t.Helper()
	path := filepath.Join(dir, "exec.json")
	if _, err := os.Stat(path); os.IsNotExist(err) {
		return nil
	}
	var e Exec
	blob, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("%s: %s", path, err)
	}
	if err := json.Unmarshal(blob, &e); err != nil {
		t.Fatalf("%s: %s", path, err)
	}
	if e.Command == "" {
		e.Command = "generate"
	}
	return &e
}

func FindTests(t *testing.T, root, testctx string) []*Testcase {
	var tcs []*Testcase
	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		name := info.Name()
		if name == "sqlc.json" || name == "sqlc.yaml" || name == "sqlc.yml" {
			dir := filepath.Dir(path)
			tcs = append(tcs, &Testcase{
				Path:       dir,
				Name:       strings.TrimPrefix(dir, root+string(filepath.Separator)),
				ConfigName: name,
				Stderr:     parseStderr(t, dir, testctx),
				Stdout:     parseStdout(t, dir),
				Exec:       parseExec(t, dir),
			})
			return filepath.SkipDir
		}
		// Config-less command tests (e.g. parse, analyze) are discovered by
		// their exec.json when no sqlc config is present in the directory.
		if name == "exec.json" {
			dir := filepath.Dir(path)
			if !hasSQLCConfig(dir) {
				tcs = append(tcs, &Testcase{
					Path:   dir,
					Name:   strings.TrimPrefix(dir, root+string(filepath.Separator)),
					Stderr: parseStderr(t, dir, testctx),
					Stdout: parseStdout(t, dir),
					Exec:   parseExec(t, dir),
				})
				return filepath.SkipDir
			}
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	return tcs
}