package db

import (
	"context"
	"errors"
	"strings"

	"apigo.cc/go/cast"
	"apigo.cc/go/file"
	"apigo.cc/go/jsmod"
)

func init() {
	jsmod.Register("db", map[string]any{
		// 入口：支持别名获取，不传则默认 "default"
		"Get": func(ctx context.Context, name *string) (*jsDB, error) {
			target := "default"
			if name != nil {
				target = *name
			}
			return getJSDB(ctx, target)
		},

		// 默认快捷调用 (面向 "default" 实例)
		"Query": func(ctx context.Context, query string, args ...any) (*QueryResult, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Query(query, args...), nil
		},
		"Exec": func(ctx context.Context, query string, args ...any) (*ExecResult, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Exec(query, args...), nil
		},
		"Insert": func(ctx context.Context, table string, data any) (*ExecResult, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Insert(table, data), nil
		},
		"Update": func(ctx context.Context, table string, data any, conditions string, args ...any) (*ExecResult, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Update(table, data, conditions, args...), nil
		},
		"Delete": func(ctx context.Context, table string, conditions string, args ...any) (*ExecResult, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Delete(table, conditions, args...), nil
		},
		"Replace": func(ctx context.Context, table string, data any) (*ExecResult, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Replace(table, data), nil
		},
		"Begin": func(ctx context.Context) (*jsTx, error) {
			jd, err := getJSDB(ctx, "default")
			if err != nil {
				return nil, err
			}
			return jd.Begin()
		},
	})
}

func getJSDB(ctx context.Context, name string) (*jsDB, error) {
	isReadOnly := false

	// 安全模式下的动态判定
	if jsmod.IsSafeMode(ctx) {
		if strings.HasPrefix(name, "sqlite://") {
			// 1. SQLite 路径校验
			path := strings.TrimPrefix(name, "sqlite://")
			if idx := strings.Index(path, "?"); idx != -1 {
				path = path[:idx]
			}
			_, err := file.VerifyPathForSafeMode(ctx, path)
			if err != nil {
				return nil, err
			}
			isReadOnly = false
		} else {
			// 2. 远程数据库前缀校验
			var allowedDSNs []string
			cast.Convert(&allowedDSNs, jsmod.Get(ctx, "AllowedDSNs"))
			matched := false
			for _, prefix := range allowedDSNs {
				if strings.HasPrefix(name, prefix) {
					matched = true
					break
				}
			}
			if !matched {
				isReadOnly = true
			}
		}
	}

	d := GetDB(name, nil)
	if d.Error != nil {
		return nil, d.Error
	}
	return &jsDB{db: d, ctx: ctx, isReadOnly: isReadOnly}, nil
}

type jsDB struct {
	db         *DB
	ctx        context.Context
	isReadOnly bool
}

var errReadOnly = errors.New("database is in read-only mode for this context")

func (jd *jsDB) checkWrite() error {
	if jd.isReadOnly {
		return errReadOnly
	}
	return nil
}

// Read Operations
func (jd *jsDB) Query(query string, args ...any) *QueryResult {
	return jd.db.Query(query, args...)
}

// Write Operations
func (jd *jsDB) Exec(query string, args ...any) *ExecResult {
	if err := jd.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jd.db.Exec(query, args...)
}

func (jd *jsDB) Insert(table string, data any) *ExecResult {
	if err := jd.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jd.db.Insert(table, data)
}

func (jd *jsDB) Update(table string, data any, conditions string, args ...any) *ExecResult {
	if err := jd.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jd.db.Update(table, data, conditions, args...)
}

func (jd *jsDB) Delete(table string, conditions string, args ...any) *ExecResult {
	if err := jd.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jd.db.Delete(table, conditions, args...)
}

func (jd *jsDB) Replace(table string, data any) *ExecResult {
	if err := jd.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jd.db.Replace(table, data)
}

// Transaction Support
func (jd *jsDB) Begin() (*jsTx, error) {
	tx := jd.db.Begin()
	if tx.Error != nil {
		return nil, tx.Error
	}
	return &jsTx{tx: tx, ctx: jd.ctx, isReadOnly: jd.isReadOnly}, nil
}

// Metadata
func (jd *jsDB) InKeys(numArgs int) string { return jd.db.InKeys(numArgs) }
func (jd *jsDB) Quote(text string) string  { return jd.db.Quote(text) }

// jsTx wraps *Tx for JS environment
type jsTx struct {
	tx         *Tx
	ctx        context.Context
	isReadOnly bool
}

func (jt *jsTx) checkWrite() error {
	if jt.isReadOnly {
		return errReadOnly
	}
	return nil
}

func (jt *jsTx) Query(query string, args ...any) *QueryResult {
	return jt.tx.Query(query, args...)
}

func (jt *jsTx) Exec(query string, args ...any) *ExecResult {
	if err := jt.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jt.tx.Exec(query, args...)
}

func (jt *jsTx) Insert(table string, data any) *ExecResult {
	if err := jt.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jt.tx.Insert(table, data)
}

func (jt *jsTx) Update(table string, data any, conditions string, args ...any) *ExecResult {
	if err := jt.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jt.tx.Update(table, data, conditions, args...)
}

func (jt *jsTx) Delete(table string, conditions string, args ...any) *ExecResult {
	if err := jt.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jt.tx.Delete(table, conditions, args...)
}

func (jt *jsTx) Replace(table string, data any) *ExecResult {
	if err := jt.checkWrite(); err != nil {
		return &ExecResult{Error: err}
	}
	return jt.tx.Replace(table, data)
}

func (jt *jsTx) Commit() error {
	if err := jt.checkWrite(); err != nil {
		return err
	}
	return jt.tx.Commit()
}

func (jt *jsTx) Rollback() error { return jt.tx.Rollback() }