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

// Database callable functions: FIELDPUT, ALIAS, DBEVAL, DBUSEAREA, DBCLOSEAREA,
// DBGOTO, DBSKIP, DBAPPEND, DBDELETE, DBRECALL, DBCOMMIT, DBSEEK,
// DBGOTOP, DBGOBOTTOM, DBRLOCKLIST, DBSETFILTER, DBCLEARFILTER

package hbrtl

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

// FIELDPUT(nField, xValue) → xValue
func rtlFieldPut(t *hbrt.Thread) {
	t.Frame(2, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetNil()
		return
	}
	nField := t.Local(1).AsInt()
	val := t.Local(2)
	area.PutValue(nField-1, val) // 1-based to 0-based
	t.RetVal(val)
}

// ALIAS([nWorkArea]) → cAlias
func rtlAlias(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetString("")
		return
	}
	area := wam.Current()
	if area != nil {
		t.RetString(area.Alias())
	} else {
		t.RetString("")
	}
}

// DBEVAL(bBlock [, bFor [, bWhile [, nCount [, nRecord [, lRest]]]]]) → NIL
func rtlDbEval(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
	}

	block := t.Local(1)
	if !block.IsBlock() {
		t.RetNil()
		return
	}

	var bFor, bWhile hbrt.Value
	nCount := -1
	lRest := false

	if nParams >= 2 {
		bFor = t.Local(2)
	}
	if nParams >= 3 {
		bWhile = t.Local(3)
	}
	if nParams >= 4 && !t.Local(4).IsNil() {
		nCount = t.Local(4).AsInt()
	}
	if nParams >= 5 && !t.Local(5).IsNil() {
		nRec := t.Local(5).AsInt()
		area.GoTo(uint32(nRec))
	}
	if nParams >= 6 && !t.Local(6).IsNil() {
		lRest = t.Local(6).AsBool()
	}

	// If not lRest and no record specified, go top
	if !lRest && (nParams < 5 || t.Local(5).IsNil()) {
		area.GoTop()
	}

	count := 0
	for !area.EOF() {
		if nCount >= 0 && count >= nCount {
			break
		}

		// While condition
		if !bWhile.IsNil() && bWhile.IsBlock() {
			blk := bWhile.AsBlock()
			t.PendingParams2(0)
			blk.Fn(t)
			if !t.GetRetValue().AsBool() {
				break
			}
		}

		// For condition
		doBlock := true
		if !bFor.IsNil() && bFor.IsBlock() {
			blk := bFor.AsBlock()
			t.PendingParams2(0)
			blk.Fn(t)
			doBlock = t.GetRetValue().AsBool()
		}

		if doBlock {
			blk := block.AsBlock()
			t.PendingParams2(0)
			blk.Fn(t)
		}

		area.Skip(1)
		count++
	}

	t.RetNil()
}

// DBUSEAREA([lNewArea], [cDriver], cName, [cAlias], [lShared], [lReadOnly]) → NIL
func rtlDbUseArea(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	cName := ""
	cAlias := ""
	cDriver := "DBFNTX"
	if nParams >= 3 && !t.Local(3).IsNil() {
		cName = t.Local(3).AsString()
	}
	if nParams >= 4 && !t.Local(4).IsNil() {
		cAlias = t.Local(4).AsString()
	}
	if nParams >= 2 && !t.Local(2).IsNil() {
		cDriver = t.Local(2).AsString()
	}
	shared := false
	readOnly := false
	if nParams >= 5 && !t.Local(5).IsNil() {
		shared = t.Local(5).AsBool()
	}
	if nParams >= 6 && !t.Local(6).IsNil() {
		readOnly = t.Local(6).AsBool()
	}
	wam.Open(cDriver, cName, cAlias, shared, readOnly)
	t.RetNil()
}

// DBCLOSEAREA() → NIL
func rtlDbCloseArea(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam != nil {
		wam.Close()
	}
	t.RetNil()
}

// DBGOTO(nRecNo) → NIL
func rtlDbGoTo(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	area := wam.Current()
	if area != nil {
		area.GoTo(uint32(t.Local(1).AsLong()))
	}
	t.RetNil()
}

// DBSKIP([nRecords]) → NIL
func rtlDbSkip(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
	}
	n := int64(1)
	if nParams >= 1 && !t.Local(1).IsNil() {
		n = t.Local(1).AsLong()
	}
	area.Skip(n)
	t.RetNil()
}

// DBGOTOP() → NIL
func rtlDbGoTop(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 {
		area.GoTop()
	}
	t.RetNil()
}

// DBGOBOTTOM() → NIL
func rtlDbGoBottom(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 {
		area.GoBottom()
	}
	t.RetNil()
}

// DBAPPEND([lUnlock]) → NIL
func rtlDbAppend(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 {
		area.Append()
	}
	t.RetNil()
}

// DBDELETE() → NIL
func rtlDbDelete(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 {
		area.Delete()
	}
	t.RetNil()
}

// DBRECALL() → NIL
func rtlDbRecall(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 {
		area.Recall()
	}
	t.RetNil()
}

// DBCOMMIT() → NIL
func rtlDbCommit(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 {
		area.Flush()
	}
	t.RetNil()
}

// DBSEEK(xValue [, lSoftSeek [, lLast]]) → lFound
func rtlDbSeek(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetBool(false)
		return
	}
	area := wam.Current()
	if area == nil {
		t.RetBool(false)
		return
	}
	val := t.Local(1)
	softSeek := false
	findLast := false
	if nParams >= 2 && !t.Local(2).IsNil() {
		softSeek = t.Local(2).AsBool()
	}
	if nParams >= 3 && !t.Local(3).IsNil() {
		findLast = t.Local(3).AsBool()
	}
	// Check if area implements Indexer
	if idx, ok := area.(hbrdd.Indexer); ok {
		found, _ := idx.Seek(val, softSeek, findLast)
		t.RetBool(found)
	} else {
		t.RetBool(false)
	}
}

// DBSELECTAREA(nArea | cAlias) → NIL
func rtlDbSelectArea(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	wam := getWA(t)
	if wam == nil {
		t.RetNil()
		return
	}
	v := t.Local(1)
	if v.IsString() {
		wam.Select(v.AsString())
	} else {
		wam.Select(uint16(v.AsInt()))
	}
	t.RetNil()
}

// DBPACK() → NIL
func rtlDbPack(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 {
		area.Pack()
	}
	t.RetNil()
}

// DBZAP() → NIL
func rtlDbZap(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 {
		area.Zap()
	}
	t.RetNil()
}

// --- LOCATE / CONTINUE ---
// Harbour: DBLOCATE(bFor, bWhile, nNext, nRec, lRest) → .T./.F.
// Searches from current position for record matching condition.

func rtlDbLocate(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

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

	// param 1: bFor condition block
	var bFor hbrt.Value
	if nParams >= 1 && !t.Local(1).IsNil() {
		bFor = t.Local(1)
	}
	// param 2: bWhile condition block
	var bWhile hbrt.Value
	if nParams >= 2 && !t.Local(2).IsNil() {
		bWhile = t.Local(2)
	}
	// param 3: nNext — max records to scan
	nNext := int64(0) // 0 = all
	if nParams >= 3 && !t.Local(3).IsNil() {
		nNext = t.Local(3).AsNumInt()
	}
	// param 4: nRec — specific record number
	if nParams >= 4 && !t.Local(4).IsNil() {
		nRec := uint32(t.Local(4).AsNumInt())
		area.GoTo(nRec)
		if bFor.IsBlock() {
			t.PendingParams2(0)
			bFor.AsBlock().Fn(t)
			result := t.Pop2()
			area.SetFound(result.AsBool())
		} else {
			area.SetFound(true)
		}
		t.RetBool(area.Found())
		return
	}
	// param 5: lRest — .T. = continue from current, .F. = from top
	lRest := false
	if nParams >= 5 && !t.Local(5).IsNil() {
		lRest = t.Local(5).AsBool()
	}

	if !lRest && nNext == 0 {
		area.GoTop()
	}

	// Store locate block for __dbContinue
	if bFor.IsBlock() {
		area.SetLocate("", func(lt *hbrt.Thread) bool {
			lt.PendingParams2(0)
			bFor.AsBlock().Fn(lt)
			return lt.Pop2().AsBool()
		})
	}

	found := false
	count := int64(0)
	for !area.EOF() {
		if nNext > 0 && count >= nNext {
			break
		}
		// Check WHILE condition
		if bWhile.IsBlock() {
			t.PendingParams2(0)
			bWhile.AsBlock().Fn(t)
			if !t.Pop2().AsBool() {
				break
			}
		}
		// Check FOR condition
		if bFor.IsBlock() {
			t.PendingParams2(0)
			bFor.AsBlock().Fn(t)
			if t.Pop2().AsBool() {
				found = true
				break
			}
		} else {
			found = true
			break
		}
		area.Skip(1)
		count++
	}
	area.SetFound(found)
	t.RetBool(found)
}

// __DBCONTINUE — continue previous LOCATE search.
// Harbour: __dbContinue()
func rtlDbContinue(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()

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

	blk := area.LocateBlock()
	if blk == nil {
		area.SetFound(false)
		t.RetBool(false)
		return
	}

	// Skip past current record
	area.Skip(1)

	found := false
	for !area.EOF() {
		if blk(t) {
			found = true
			break
		}
		area.Skip(1)
	}
	area.SetFound(found)
	t.RetBool(found)
}

// --- DBSETFILTER / DBCLEARFILTER / DBFILTER ---

// DBSETFILTER(bCondition [, cCondition])
func rtlDbSetFilter(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.Local(1).IsBlock() {
		bFilter := t.Local(1)
		expr := ""
		if nParams >= 2 && t.Local(2).IsString() {
			expr = t.Local(2).AsString()
		}
		area.SetFilter(expr, func(lt *hbrt.Thread) bool {
			lt.PendingParams2(0)
			bFilter.AsBlock().Fn(lt)
			return lt.Pop2().AsBool()
		})
	}
	t.RetNil()
}

// DBCLEARFILTER()
func rtlDbClearFilter(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()

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

// DBFILTER() → cFilterExpression
func rtlDbFilter(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()

	// TODO: return stored filter expression from area
	t.RetString("")
}