// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

// Index and database introspection RTL functions.
// Harbour: INDEXORD, INDEXKEY, ORDSETFOCUS, ORDCOUNT, ORDNAME, ORDKEY,
// ORDFOR, ORDSCOPE, DBORDERINFO, DBINFO, DBCREATE, RDDSETDEFAULT

package hbrtl

import (
	"five/hbrt"
	"five/hbrdd"
	"five/hbrdd/dbf"
	"fmt"
)

// INDEXORD() → nCurrentOrder (1-based, 0 = natural)
func IndexOrd(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam != nil {
		if area := wam.Current(); area != nil {
			if da, ok := area.(*dbf.DBFArea); ok {
				t.RetInt(int64(da.CurrentOrder()))
				return
			}
		}
	}
	t.RetInt(0)
}

// INDEXKEY([nOrder]) → cKeyExpression
func IndexKey(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam != nil {
		if area := wam.Current(); area != nil {
			if da, ok := area.(*dbf.DBFArea); ok {
				n := da.CurrentOrder()
				if nParams >= 1 && !t.Local(1).IsNil() {
					n = t.Local(1).AsInt()
				}
				t.RetString(da.OrderKeyExpr(n))
				return
			}
		}
	}
	t.RetString("")
}

// ORDSETFOCUS([nOrder|cTag [, cBagName]]) → nOldOrder
func OrdSetFocus(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetInt(0)
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetInt(0)
		return
	}
	da, isDa := area.(*dbf.DBFArea)
	oldOrd := 0
	if isDa {
		oldOrd = da.CurrentOrder()
	}
	if nParams >= 1 && !t.Local(1).IsNil() {
		if idx, ok := area.(hbrdd.Indexer); ok {
			v := t.Local(1)
			if v.IsNumeric() {
				// SET ORDER TO n — convert number to digit string for OrderListFocus
				idx.OrderListFocus(fmt.Sprintf("%d", v.AsNumInt()))
			} else {
				idx.OrderListFocus(v.AsString())
			}
		}
	}
	t.RetInt(int64(oldOrd))
}

// ORDCOUNT([cBagName]) → nOrders
func OrdCount(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam != nil {
		if area := wam.Current(); area != nil {
			if da, ok := area.(*dbf.DBFArea); ok {
				t.RetInt(int64(da.IndexCount()))
				return
			}
		}
	}
	t.RetInt(0)
}

// ORDLISTREBUILD — REINDEX equivalent. Rebuilds every attached index
// from current DBF data. Called at the tail of SQL DML (INSERT /
// UPDATE / DELETE) because `DBFArea.Append` / `PutValue` / `Delete`
// don't yet have per-key ordKeyAdd / ordKeyDel hooks — the full
// rebuild is the sledge-hammer that keeps the NTX on disk in sync
// with the .dbf. No-op when no index is attached.
func OrdListRebuild(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	if idx, ok := area.(hbrdd.Indexer); ok {
		_ = idx.OrderListRebuild()
	}
	t.RetNil()
}

// ORDNAME([nOrder [, cBagName]]) → cTagName
func OrdName(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam != nil {
		if area := wam.Current(); area != nil {
			if da, ok := area.(*dbf.DBFArea); ok {
				n := da.CurrentOrder()
				if nParams >= 1 && !t.Local(1).IsNil() {
					n = t.Local(1).AsInt()
				}
				t.RetString(da.OrderName(n))
				return
			}
		}
	}
	t.RetString("")
}

// ORDKEY([nOrder [, cBagName]]) → cKeyExpression
func OrdKey(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam != nil {
		if area := wam.Current(); area != nil {
			if da, ok := area.(*dbf.DBFArea); ok {
				n := da.CurrentOrder()
				if nParams >= 1 && !t.Local(1).IsNil() {
					n = t.Local(1).AsInt()
				}
				t.RetString(da.OrderKeyExpr(n))
				return
			}
		}
	}
	t.RetString("")
}

// ORDFOR([nOrder [, cBagName]]) → cForExpression
func OrdFor(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	// TODO: return FOR expression from index
	t.RetString("")
}

// ORDSCOPE(nScope [, xValue]) → xOldValue
// nScope: 0 = TOPSCOPE, 1 = BOTTOMSCOPE
// If xValue omitted, returns current scope. If xValue given, sets scope and returns old.
// Harbour: TOPSCOPE = 0, BOTTOMSCOPE = 1
func OrdScope(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	da, ok := area.(*dbf.DBFArea)
	if !ok {
		t.RetNil()
		return
	}

	nScope := 0
	if nParams >= 1 {
		nScope = t.Local(1).AsInt()
	}

	// Get old scope value
	var oldScope []byte
	if nScope == 0 {
		oldScope = da.GetScopeTop()
	} else {
		oldScope = da.GetScopeBottom()
	}

	if oldScope != nil {
		t.PushString(string(oldScope))
	} else {
		t.PushNil()
	}

	// Set new scope if value provided
	if nParams >= 2 {
		val := t.Local(2)
		if val.IsNil() {
			if nScope == 0 {
				da.ClearScopeTop()
			} else {
				da.ClearScopeBottom()
			}
		} else {
			if nScope == 0 {
				da.SetScopeTop(val)
			} else {
				da.SetScopeBottom(val)
			}
		}
	}

	t.RetValue()
}

// DBI_* constants. Mirror include/dbinfo.ch. Only the ones we actually
// answer are listed — unknown codes return NIL.
const (
	dbiIsDBF         = 1
	dbiCanPutRec     = 2
	dbiGetHeaderSize = 3
	dbiLastUpdate    = 4
	dbiGetRecSize    = 7
	dbiTableExt      = 9
	dbiFullPath      = 10
	dbiMemoExt       = 11
	dbiDBVersion     = 12
	dbiRDDVersion    = 13
	dbiShared        = 42
	dbiIsReadOnly    = 43
	dbiPositioned    = 45
	dbiLockCount     = 49
	dbiBOF           = 51
	dbiEOF           = 52
	dbiFound         = 54
	dbiFCount        = 55
	dbiAlias         = 56
)

// DBINFO(nInfoType [, xNewSetting]) → xInfo
//
// Queries workarea metadata. Only the setters that change observable
// state are implemented; unknown info codes return NIL (Harbour's
// forgiving behavior). xNewSetting is accepted but only honored for
// fields where it makes sense.
func DbInfo(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}

	if nParams < 1 {
		t.RetNil()
		return
	}
	nInfo := int(t.Local(1).AsNumInt())

	// DBF-specific queries
	if da, ok := area.(*dbf.DBFArea); ok {
		switch nInfo {
		case dbiIsDBF:
			t.RetBool(true)
			return
		case dbiCanPutRec:
			t.RetBool(!da.IsReadOnly())
			return
		case dbiFullPath:
			t.RetString(da.FullPath())
			return
		case dbiTableExt:
			t.RetString(".dbf")
			return
		case dbiMemoExt:
			if da.MemoFile() != nil {
				t.RetString(".fpt")
			} else {
				t.RetString("")
			}
			return
		case dbiShared:
			t.RetBool(da.IsShared())
			return
		case dbiIsReadOnly:
			t.RetBool(da.IsReadOnly())
			return
		case dbiGetRecSize:
			nCount, _ := da.RecCount()
			_ = nCount
			// Header + records length — approximation from FieldInfo
			total := 0
			for i := 0; i < da.FieldCount(); i++ {
				total += da.GetFieldInfo(i).Len
			}
			t.RetInt(int64(total + 1)) // +1 for delete flag
			return
		case dbiDBVersion:
			t.RetString("Five DBF 1.0")
			return
		case dbiRDDVersion:
			t.RetString("Five 1.0")
			return
		}
	}

	// Generic (any Area) queries
	switch nInfo {
	case dbiBOF:
		t.RetBool(area.BOF())
		return
	case dbiEOF:
		t.RetBool(area.EOF())
		return
	case dbiFound:
		t.RetBool(area.Found())
		return
	case dbiFCount:
		t.RetInt(int64(area.FieldCount()))
		return
	case dbiAlias:
		t.RetString(area.Alias())
		return
	case dbiPositioned:
		t.RetBool(!area.BOF() && !area.EOF())
		return
	}

	t.RetNil()
}

// DBOI_* constants. Mirror include/dbinfo.ch.
const (
	dboiCondition   = 1
	dboiExpression  = 2
	dboiPosition    = 3
	dboiName        = 4
	dboiNumber      = 5
	dboiBagName     = 6
	dboiBagExt      = 7
	dboiIndexName   = 8
	dboiOrderCount  = 9
	dboiIsCond      = 11
	dboiIsDesc      = 12
	dboiUnique      = 13
	dboiKeyType     = 14
	dboiKeySize     = 15
	dboiKeyCount    = 22
	dboiKeyCountRaw = 34
)

// DBORDERINFO(nInfoType [, cBagName [, nOrder [, xNewSetting]]]) → xInfo
//
// Queries metadata about an active order (index). The order is identified
// by nOrder (1-based) or defaults to the current focus.
func DbOrderInfo(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	da, ok := area.(*dbf.DBFArea)
	if !ok {
		t.RetNil()
		return
	}

	if nParams < 1 {
		t.RetNil()
		return
	}
	nInfo := int(t.Local(1).AsNumInt())

	// Resolve which order we're asking about.
	ord := da.CurrentOrder()
	if nParams >= 3 && !t.Local(3).IsNil() {
		ord = int(t.Local(3).AsNumInt())
	}

	switch nInfo {
	case dboiExpression:
		t.RetString(da.OrderKeyExpr(ord))
		return
	case dboiName:
		t.RetString(da.OrderName(ord))
		return
	case dboiNumber, dboiPosition:
		t.RetInt(int64(ord))
		return
	case dboiOrderCount:
		t.RetInt(int64(da.IndexCount()))
		return
	case dboiKeyCount, dboiKeyCountRaw:
		n, _ := da.RecCount()
		t.RetInt(int64(n))
		return
	case dboiKeySize:
		// Byte length of the stored keys for this order. TSqlIndex:BuildKey
		// uses this to right-size numeric scope keys — otherwise a hard-coded
		// Str(xValue, 10) produces bytes that don't align with the 8-byte
		// index keys for N(8,0) columns, and ordScope silently fails to
		// constrain the scan.
		t.RetInt(int64(da.OrderKeyLen(ord)))
		return
	}

	t.RetNil()
}

// ORDINFO(nInfoType [, cOrder]) → xInfo
func OrdInfo(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	t.RetNil()
}

// RDDSETDEFAULT([cDriver]) → cOldDriver
func RddSetDefault(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	t.RetString("DBFNTX")
}

// FIELDTYPE(n) → cType — one-letter type ("C"/"N"/"L"/"D"/"M"/...)
// Harbour: field descriptor type byte from current workarea.
func FieldType(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetString("")
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetString("")
		return
	}
	n := t.Local(1).AsInt() - 1
	if n < 0 || n >= area.FieldCount() {
		t.RetString("")
		return
	}
	fi := area.GetFieldInfo(n)
	t.RetString(string(fi.Type))
}

// FIELDLEN(n) → nLen — field length in bytes.
func FieldLen(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetInt(0)
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetInt(0)
		return
	}
	n := t.Local(1).AsInt() - 1
	if n < 0 || n >= area.FieldCount() {
		t.RetInt(0)
		return
	}
	fi := area.GetFieldInfo(n)
	t.RetInt(int64(fi.Len))
}

// FIELDDEC(n) → nDecimals — field decimal places.
func FieldDec(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetInt(0)
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetInt(0)
		return
	}
	n := t.Local(1).AsInt() - 1
	if n < 0 || n >= area.FieldCount() {
		t.RetInt(0)
		return
	}
	fi := area.GetFieldInfo(n)
	t.RetInt(int64(fi.Dec))
}

// ORDCREATE(cBagName, cTagName, cKeyExpr [, bKeyExpr] [, lUnique])
// Creates a new index (CDX tag or NTX file). Uses MacroEval slow path
// for the key expression since Callers pass a string literal.
func OrdCreate(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	idx, ok := area.(hbrdd.Indexer)
	if !ok {
		t.RetNil()
		return
	}

	cBag := ""
	if nParams >= 1 && !t.Local(1).IsNil() {
		cBag = t.Local(1).AsString()
	}
	cTag := ""
	if nParams >= 2 && !t.Local(2).IsNil() {
		cTag = t.Local(2).AsString()
	}
	cExpr := ""
	if nParams >= 3 && !t.Local(3).IsNil() {
		cExpr = t.Local(3).AsString()
	}
	lUnique := false
	if nParams >= 5 && !t.Local(5).IsNil() {
		lUnique = t.Local(5).AsBool()
	}

	_ = idx.OrderCreate(hbrdd.OrderCreateParams{
		TagName:  cTag,
		KeyExpr:  cExpr,
		FilePath: cBag,
		Unique:   lUnique,
	})
	t.RetNil()
}

// DBCREATEINDEX(cFile, cKeyExpr [, bKeyExpr] [, lUnique])
// Legacy (Clipper) single-tag NTX index creation. Tag name defaults
// to the bare filename.
func DbCreateIndex(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	idx, ok := area.(hbrdd.Indexer)
	if !ok {
		t.RetNil()
		return
	}

	cFile := ""
	if nParams >= 1 && !t.Local(1).IsNil() {
		cFile = t.Local(1).AsString()
	}
	cExpr := ""
	if nParams >= 2 && !t.Local(2).IsNil() {
		cExpr = t.Local(2).AsString()
	}
	lUnique := false
	if nParams >= 4 && !t.Local(4).IsNil() {
		lUnique = t.Local(4).AsBool()
	}

	_ = idx.OrderCreate(hbrdd.OrderCreateParams{
		KeyExpr:  cExpr,
		FilePath: cFile,
		Unique:   lUnique,
	})
	t.RetNil()
}

// DBCLEARINDEX() — close all open index bags on current workarea.
func DbClearIndex(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	if idx, ok := area.(hbrdd.Indexer); ok {
		_ = idx.OrderListClear()
	}
	t.RetNil()
}

// DBCREATE(cFile, aStruct [, cDriver]) → NIL
func DbCreate(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	cFile := t.Local(1).AsString()
	aStruct := t.Local(2)
	cDriver := "DBFNTX"
	if nParams >= 3 && !t.Local(3).IsNil() {
		cDriver = t.Local(3).AsString()
	}

	if !aStruct.IsArray() {
		t.RetNil()
		return
	}

	arr := aStruct.AsArray()
	fields := make([]hbrdd.FieldInfo, len(arr.Items))
	for i, item := range arr.Items {
		row := item.AsArray()
		if row == nil || len(row.Items) < 4 {
			continue
		}
		fields[i] = hbrdd.FieldInfo{
			Name: row.Items[0].AsString(),
			Type: row.Items[1].AsString()[0],
			Len:  row.Items[2].AsInt(),
			Dec:  row.Items[3].AsInt(),
		}
		// Optional 5th element: field flag byte (e.g. FieldFlagNullable
		// = 0x02). Pre-nullable callers pass 4-element rows and leave
		// Flags at zero, so the hidden _NullFlags column is only added
		// when a caller explicitly opts a column in.
		if len(row.Items) >= 5 && row.Items[4].IsNumeric() {
			fields[i].Flags = byte(row.Items[4].AsInt())
		}
	}

	drv, err := hbrdd.GetDriver(cDriver)
	if err != nil {
		t.RetNil()
		return
	}
	drv.Create(hbrdd.CreateParams{
		Path:   cFile,
		Fields: fields,
	})
	t.RetNil()
}