package db

import (
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"

	"visiona-backend/internal/config"
)

// DSN / SafeTarget 為純函式，不需 DB，故不帶 dbtest tag，預設 go test 即執行。

func TestBuildDSN_Basic(t *testing.T) {
	cfg := config.DatabaseConfig{
		Host:     "db.example.com",
		Port:     5432,
		User:     "appuser",
		Password: "s3cret",
		DBName:   "visiona",
		SSLMode:  "require",
		MaxConns: 10,
		MinConns: 2,
	}
	dsn := BuildDSN(cfg)

	assert.True(t, strings.HasPrefix(dsn, "postgres://"), "scheme 應為 postgres://，got %s", dsn)
	assert.Contains(t, dsn, "appuser:s3cret@db.example.com:5432/visiona")
	assert.Contains(t, dsn, "sslmode=require")
	assert.Contains(t, dsn, "pool_max_conns=10")
	assert.Contains(t, dsn, "pool_min_conns=2")
}

func TestBuildDSN_PasswordWithSpecialChars(t *testing.T) {
	cfg := config.DatabaseConfig{
		Host:     "localhost",
		Port:     5432,
		User:     "user@org",
		Password: "p@ss:w/rd?x",
		DBName:   "db",
		SSLMode:  "disable",
	}
	dsn := BuildDSN(cfg)

	// 特殊字元應被 percent-encode，不破壞 DSN 結構（仍能被解析）。
	assert.NotContains(t, dsn, "p@ss:w/rd?x", "密碼特殊字元應被 encode")
	assert.Contains(t, dsn, "sslmode=disable")
}

func TestBuildDSN_DefaultSSLMode(t *testing.T) {
	cfg := config.DatabaseConfig{Host: "h", Port: 5432, User: "u", DBName: "d"}
	dsn := BuildDSN(cfg)
	assert.Contains(t, dsn, "sslmode=require", "SSLMode 留空應預設 require")
}

func TestSafeTarget_NoCredentials(t *testing.T) {
	cfg := config.DatabaseConfig{
		Host:     "db.example.com",
		Port:     5432,
		User:     "appuser",
		Password: "topsecret",
		DBName:   "visiona",
	}
	target := SafeTarget(cfg)

	assert.Equal(t, "db.example.com:5432/visiona", target)
	assert.NotContains(t, target, "appuser", "SafeTarget 不應含 user")
	assert.NotContains(t, target, "topsecret", "SafeTarget 不應含密碼")
}

func TestSafeTarget_DefaultPort(t *testing.T) {
	cfg := config.DatabaseConfig{Host: "h", DBName: "d"}
	assert.Equal(t, "h:5432/d", SafeTarget(cfg))
}

func TestDatabaseConfig_Enabled(t *testing.T) {
	cases := []struct {
		name string
		cfg  config.DatabaseConfig
		want bool
	}{
		{"all set", config.DatabaseConfig{Host: "h", User: "u", DBName: "d"}, true},
		{"missing host", config.DatabaseConfig{User: "u", DBName: "d"}, false},
		{"missing user", config.DatabaseConfig{Host: "h", DBName: "d"}, false},
		{"missing dbname", config.DatabaseConfig{Host: "h", User: "u"}, false},
		{"empty", config.DatabaseConfig{}, false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			assert.Equal(t, tc.want, tc.cfg.Enabled())
		})
	}
}

func TestRedisConfig_Enabled(t *testing.T) {
	assert.True(t, config.RedisConfig{Host: "h"}.Enabled())
	assert.False(t, config.RedisConfig{}.Enabled())
}

// migrateDSN 應把 postgres:// scheme 去掉（golang-migrate pgx5 driver 期望的形式）。
func TestMigrateDSN_StripsScheme(t *testing.T) {
	cfg := config.DatabaseConfig{
		Host: "h", Port: 5432, User: "u", Password: "pw", DBName: "d", SSLMode: "disable",
		ConnTimeout: 5 * time.Second,
	}
	got := migrateDSN(cfg)
	assert.False(t, strings.HasPrefix(got, "postgres://"), "migrateDSN 不應保留 postgres:// prefix，got %s", got)
	assert.Contains(t, got, "@h:5432/d")
}

// Regression（塊 0 修正）：migrateDSN 絕不可帶 pgxpool 專屬參數。
// golang-migrate 的 pgx5 driver 走標準 database/sql 單連線，PG server 端不認得
// pool_max_conns / pool_min_conns，會直接 FATAL（SQLSTATE 42704）導致所有 migration 失敗。
// 這個無 docker 也能跑的純函式測試，確保不會再 regression。
func TestMigrateDSN_NoPoolParams(t *testing.T) {
	cfg := config.DatabaseConfig{
		Host: "h", Port: 5432, User: "u", Password: "pw", DBName: "d", SSLMode: "disable",
		MaxConns: 10, MinConns: 2,
	}
	got := migrateDSN(cfg)

	assert.NotContains(t, got, "pool_max_conns", "migrateDSN 不可帶 pgxpool 專屬參數 pool_max_conns，got %s", got)
	assert.NotContains(t, got, "pool_min_conns", "migrateDSN 不可帶 pgxpool 專屬參數 pool_min_conns，got %s", got)
	// 標準 libpq 參數仍須正確帶上。
	assert.Contains(t, got, "sslmode=disable", "migrateDSN 應保留 sslmode，got %s", got)

	// 對照組：BuildDSN（pgxpool 路徑）仍應帶 pool 參數。
	pool := BuildDSN(cfg)
	assert.Contains(t, pool, "pool_max_conns=10", "BuildDSN 應保留 pool_max_conns")
	assert.Contains(t, pool, "pool_min_conns=2", "BuildDSN 應保留 pool_min_conns")
}