package game

// passages.c — draw the connecting passages.

// doPassages draws all the passages on a level (passages.c do_passages).
func (g *RogueGame) doPassages() {
	var (
		isconn  [MaxRooms][MaxRooms]bool
		ingraph [MaxRooms]bool
	)

	// starting with one room, connect it to a random adjacent room and
	// then pick a new room to start with.
	roomcount := 1
	r1 := g.rnd(MaxRooms)
	ingraph[r1] = true

	for {
		// find a room to connect with
		j := 0
		r2 := -1

		for i := range MaxRooms {
			if g.data.rdesConn[r1][i] && !ingraph[i] {
				if j++; g.rnd(j) == 0 {
					r2 = i
				}
			}
		}

		if j == 0 {
			// if no adjacent rooms are outside the graph, pick a new room
			// to look from
			for {
				r1 = g.rnd(MaxRooms)
				if ingraph[r1] {
					break
				}
			}
		} else {
			// otherwise, connect new room to the graph, and draw a tunnel
			// to it
			ingraph[r2] = true //nolint:gosec // G602: rnd(MaxRooms) bounded
			g.conn(r1, r2)
			isconn[r1][r2] = true
			isconn[r2][r1] = true //nolint:gosec // G602: rnd(MaxRooms) bounded
			roomcount++
		}

		if roomcount >= MaxRooms {
			break
		}
	}

	// attempt to add passages to the graph a random number of times so that
	// there isn't always just one unique passage through it.
	for roomcount = g.rnd(5); roomcount > 0; roomcount-- {
		r1 = g.rnd(MaxRooms) // a random room to look from
		// find an adjacent room not already connected
		j := 0
		r2 := -1

		for i := range MaxRooms {
			if g.data.rdesConn[r1][i] && !isconn[r1][i] {
				if j++; g.rnd(j) == 0 {
					r2 = i
				}
			}
		}
		// if there is one, connect it and look for the next added passage
		if j != 0 {
			g.conn(r1, r2)
			isconn[r1][r2] = true
			isconn[r2][r1] = true //nolint:gosec // G602: rnd(MaxRooms) bounded
		}
	}

	g.passnum()
}

// conn draws a corridor from a room in a certain direction (passages.c
// conn).
func (g *RogueGame) conn(r1, r2 int) {
	var (
		rm    int
		direc byte
	)

	if r1 < r2 {
		rm = r1
		if r1+1 == r2 {
			direc = 'r'
		} else {
			direc = 'd'
		}
	} else {
		rm = r2
		if r2+1 == r1 {
			direc = 'r'
		} else {
			direc = 'd'
		}
	}

	rpf := &g.Level.Rooms[rm]

	// Set up the movement variables, in two cases: first drawing one down.
	var (
		rpt                        *Room
		del, turnDelta, spos, epos Coord
		distance, turnDistance     int
	)

	if direc == 'd' {
		rmt := rm + 3             // room # of dest
		rpt = &g.Level.Rooms[rmt] // room pointer of dest
		del = Coord{X: 0, Y: 1}   // direction of move
		spos = rpf.Pos            // start of move
		epos = rpt.Pos            // end of move

		if !rpf.Flags.Has(Gone) { // if not gone pick door pos
			for {
				spos.X = rpf.Pos.X + g.rnd(rpf.Max.X-2) + 1

				spos.Y = rpf.Pos.Y + rpf.Max.Y - 1
				if !rpf.Flags.Has(Maze) || g.Level.FlagsAt(spos.Y, spos.X).Has(FPassage) {
					break
				}
			}
		}

		if !rpt.Flags.Has(Gone) {
			for {
				epos.X = rpt.Pos.X + g.rnd(rpt.Max.X-2) + 1
				if !rpt.Flags.Has(Maze) || g.Level.FlagsAt(epos.Y, epos.X).Has(FPassage) {
					break
				}
			}
		}

		distance = abs(spos.Y-epos.Y) - 1 // distance to move

		turnDelta.Y = 0 // direction to turn
		if spos.X < epos.X {
			turnDelta.X = 1
		} else {
			turnDelta.X = -1
		}

		turnDistance = abs(spos.X - epos.X) // how far to turn
	} else { // setup for moving right
		rmt := rm + 1
		rpt = &g.Level.Rooms[rmt]
		del = Coord{X: 1, Y: 0}
		spos = rpf.Pos
		epos = rpt.Pos

		if !rpf.Flags.Has(Gone) {
			for {
				spos.X = rpf.Pos.X + rpf.Max.X - 1

				spos.Y = rpf.Pos.Y + g.rnd(rpf.Max.Y-2) + 1
				if !rpf.Flags.Has(Maze) || g.Level.FlagsAt(spos.Y, spos.X).Has(FPassage) {
					break
				}
			}
		}

		if !rpt.Flags.Has(Gone) {
			for {
				epos.Y = rpt.Pos.Y + g.rnd(rpt.Max.Y-2) + 1
				if !rpt.Flags.Has(Maze) || g.Level.FlagsAt(epos.Y, epos.X).Has(FPassage) {
					break
				}
			}
		}

		distance = abs(spos.X-epos.X) - 1
		if spos.Y < epos.Y {
			turnDelta.Y = 1
		} else {
			turnDelta.Y = -1
		}

		turnDelta.X = 0
		turnDistance = abs(spos.Y - epos.Y)
	}

	turnSpot := g.rnd(distance-1) + 1 // where turn starts

	// Draw in the doors on either side of the passage or just put #'s if
	// the rooms are gone.
	if !rpf.Flags.Has(Gone) {
		g.door(rpf, spos)
	} else {
		g.putpass(spos)
	}

	if !rpt.Flags.Has(Gone) {
		g.door(rpt, epos)
	} else {
		g.putpass(epos)
	}
	// Get ready to move...
	curr := spos
	for distance > 0 {
		// Move to new position
		curr.X += del.X
		curr.Y += del.Y
		// Check if we are at the turn place, if so do the turn
		if distance == turnSpot {
			for ; turnDistance > 0; turnDistance-- {
				g.putpass(curr)
				curr.X += turnDelta.X
				curr.Y += turnDelta.Y
			}
		}
		// Continue digging along
		g.putpass(curr)

		distance--
	}

	curr.X += del.X

	curr.Y += del.Y
	if curr != epos {
		g.msg("warning, connectivity problem on this level")
	}
}

// putpass adds a passage character or secret passage here (passages.c
// putpass).
func (g *RogueGame) putpass(cp Coord) {
	pp := g.Level.At(cp.Y, cp.X)
	pp.Flags.Set(FPassage)

	if g.rnd(10)+1 < g.Depth && g.rnd(40) == 0 {
		pp.Flags.Clear(FReal)
	} else {
		pp.Ch = Passage
	}
}

// door adds a door or possibly a secret door; also enters the door in the
// exits array of the room (passages.c door).
func (g *RogueGame) door(rm *Room, cp Coord) {
	rm.Exits = append(rm.Exits, cp)

	if rm.Flags.Has(Maze) {
		return
	}

	pp := g.Level.At(cp.Y, cp.X)
	if g.rnd(10)+1 < g.Depth && g.rnd(5) == 0 {
		if cp.Y == rm.Pos.Y || cp.Y == rm.Pos.Y+rm.Max.Y-1 {
			pp.Ch = '-'
		} else {
			pp.Ch = '|'
		}

		pp.Flags.Clear(FReal)
	} else {
		pp.Ch = Door
	}
}

// addPass adds the passages to the current window — wizard command
// (passages.c add_pass).
func (g *RogueGame) addPass() {
	for y := 1; y < NumLines-1; y++ {
		for x := range NumCols {
			pp := g.Level.At(y, x)
			if pp.Flags.Has(FPassage) || pp.Ch == Door ||
				(!pp.Flags.Has(FReal) && (pp.Ch == '|' || pp.Ch == '-')) {
				ch := pp.Ch
				if pp.Flags.Has(FPassage) {
					ch = Passage
				}

				pp.Flags.Set(FSeen)
				g.move(y, x)

				switch {
				case pp.Monst != nil:
					pp.Monst.OldCh = pp.Ch
				case pp.Flags.Has(FReal):
					g.addch(ch)
				default:
					g.standout()

					if pp.Flags.Has(FPassage) {
						g.addch(Passage)
					} else {
						g.addch(Door)
					}

					g.standend()
				}
			}
		}
	}
}

// passnum assigns a number to each passageway (passages.c passnum).
func (g *RogueGame) passnum() {
	g.pnum = 0

	g.newpnum = false
	for i := range g.Level.Passages {
		g.Level.Passages[i].Exits = g.Level.Passages[i].Exits[:0]
	}

	for i := range g.Level.Rooms {
		rp := &g.Level.Rooms[i]
		for j := range rp.Exits {
			g.newpnum = true
			g.numpass(rp.Exits[j].Y, rp.Exits[j].X)
		}
	}
}

// numpass numbers a passageway square and its brethren (passages.c
// numpass).
func (g *RogueGame) numpass(y, x int) {
	if x >= NumCols || x < 0 || y >= NumLines || y <= 0 {
		return
	}

	fp := g.Level.FlagsAt(y, x)
	if fp.Has(FPassNum) {
		return
	}

	if g.newpnum {
		g.pnum++
		g.newpnum = false
	}
	// check to see if it is a door or secret door, i.e., a new exit, or a
	// numerable type of place
	if ch := g.Level.Char(y, x); ch == Door ||
		(!fp.Has(FReal) && (ch == '|' || ch == '-')) {
		rp := &g.Level.Passages[g.pnum]
		rp.Exits = append(rp.Exits, Coord{Y: y, X: x})
	} else if !fp.Has(FPassage) {
		return
	}

	*fp |= PlaceFlags(g.pnum) //nolint:gosec // G115: pnum < MaxPass=13
	// recurse on the surrounding places
	g.numpass(y+1, x)
	g.numpass(y-1, x)
	g.numpass(y, x+1)
	g.numpass(y, x-1)
}

// abs is C abs() for ints.
func abs(n int) int {
	if n < 0 {
		return -n
	}

	return n
}