package main

import (
	"fmt"
	"git.kiefte.eu/lapingvino/clitris/tris"
	"github.com/pkg/term"
	"math/rand"
	"time"
	"os"
	"strconv"
)

func pos(l, c int) {
	fmt.Printf("\033[%d;%dH", l, c)
}

func ppos(l, c int, s string) {
	pos(l, c)
	fmt.Print(s)
}

func fpos(l, c int, f tris.Field) {
	pos(l, c)
	for i, r := range f {
		ppos(l+i, c, render(r, "\u2588\u2589", "\u2591\u2591")+"|")
	}
}

func npos(l, c int, f tris.Field) {
	pos(l, c)
	for i, r := range f {
		ppos(l+i, c, render(r, "\u2588\u2589", "  "))
	}
}

func render(r []int, block, empty string) string {
	var s string
	for _, c := range r {
		if c > 0 {
			s += fmt.Sprintf("\033[%dm%s\033[0m", c, block)
		} else {
			s += empty
		}
	}
	return s
}

// GetKey() returns the key currently pressed. It always returns a 3 byte slice. Check first element for Escape for handling arrow keys
// Because a defer would trigger too late and the Restore and Close are essential, separated in a function.
func GetKey(t *term.Term) []byte {
	key := make([]byte, 3)
	t.Read(key)
	return key
}

func main() {
	var startlevel int
	if len(os.Args) > 1 {
		startlevel, _ = strconv.Atoi(os.Args[1])
	}
	t, _ := term.Open("/dev/tty")
	defer t.Close()

	term.RawMode(t)
	defer t.Restore()
	defer pos(23, 0) // Set the cursor to just below the playing field

	t.SetReadTimeout(time.Second / 1000)

	rand.Seed(time.Now().UnixNano()) // to start with truly random pieces

	f := tris.NewField(20, 10)                 // the playing field (10x20)
	var floor, topout, harddrop bool // state machine variables to check special situations

	// define outside of game loop to avoid accidental resets of position
	// x, y and rot are the values calculated to feed to Move
	// which then checks collisions and does the wall kicks
	var x, y int
	var rot tris.Rotation

	var level, linescleared, score, dropfrom int

	// init variable for pressed key - MUST be initialized 3 long to avoid crash, GetKey() does this
	key := GetKey(t)

	fmt.Print("\033[2J") // Clear screen
	b := tris.NewBag()
	b, p := b.Pick()
	lev := time.NewTicker(time.Second)
	level = 1
	for {
		x, y, rot = p.X, p.Y, p.Rot
		if level > startlevel || linescleared > startlevel * 10 {
			level = linescleared/10 + 1
		} else {
			level = startlevel
		}
		slevel := fmt.Sprintf("level %d", level)
		sscore := fmt.Sprintf("score %d", score)
		slines := fmt.Sprintf("lines %d", linescleared)
		if !harddrop {
			ppos(0, 0, "Hold (c)")
			npos(3, 0, tris.HoldBox)
			fpos(0, 10, f.Add(p))
			var next tris.Field
			b, next = b.Next(5)
			npos(0, 34, next)
			ppos(1, 42, sscore)
			ppos(3, 42, slevel)
			ppos(5, 42, slines)
			key = GetKey(t)
		}
		switch key[0] {
		case 27: // Escape, read the arrow key pressed
			switch key[2] {
			case 65: // Up
				rot = (p.Rot + 1) % 4
			case 66: // Down
				y = p.Y + 1
				score += 1
			case 67: // Right
				x = p.X + 1
			case 68: // Left
				x = p.X - 1
			default:
				ppos(22, 0, "...escape, escape!")
				return
			}
		case 'w', 'i': // Up
				rot = (p.Rot + 1) % 4
		case 's', 'k': // Down
				y = p.Y + 1
				score += 1
		case 'd', 'l': // Right
				x = p.X + 1
		case 'a', 'j': // Left
				x = p.X - 1
		case 'x', '.':
			rot = (p.Rot + 1) % 4
		case 'z', ',':
			rot = (p.Rot + 3) % 4
		case 'c':
			b, p = b.Swap(p)
			continue
		case ' ':
			if !harddrop {
				dropfrom = p.Y
			}
			harddrop = true
		case 'q':
			ppos(22, 0, "...that was exciting!")
			return
		case 'Q':
			ppos(22, 0, "...never let an engineer pick the name of your software?")
			return
		}
		select {
		case <-lev.C:
			y = p.Y + 1
			lev.Reset(time.Second * 100 / (100 * time.Duration(level)))
		default:
			if harddrop {
				y = p.Y + 1
			}
		}
		p, floor, topout = p.Move(f, rot, x, y) // Check if the piece can move, then do it and communicate back for housekeeping

		// Give some time before actually locking in to enable tucks
		// This code runs when the time is over
		if floor && p.Lock.Add(tris.LockDelay).Before(time.Now()) {
			if harddrop {
				score += 2 * (p.Y - dropfrom)
				harddrop = false
			}
			var l int
			f = f.Add(p)
			l, f = f.Lines() // count and remove full lines
			if l > 0 {
				linescleared += l
				score += 40 * level * l * l
			}
			fmt.Print("\033[2J") // Clear screen
			b, p = b.Pick()      // ... and pick a new piece from the bag
		}
		// when not touching a piece or floor below yet, reset lock delay
		if !floor {
			p.Lock = time.Now()
		}

		if topout {
			ppos(4, 15, " GAME OVER ")
			return
		}
	}
}