package docs_test

import (
	"os"
	"regexp"
	"strconv"
	"strings"
	"testing"

	"halcyon/docs"
	"halcyon/sim"
)

// portValues maps the names used in the manual and in examples/programs/ports.s
// to the simulator's real port numbers, so the documentation cannot drift.
var portValues = map[string]int{
	"TURN": sim.PortTurn, "DAY": sim.PortDay, "TURNS": sim.PortTurns,
	"POSX": sim.PortPosX, "POSY": sim.PortPosY, "POSZ": sim.PortPosZ,
	"VELX": sim.PortVelX, "VELY": sim.PortVelY, "VELZ": sim.PortVelZ,
	"THROTTLE": sim.PortThrottle, "AZIMUTH": sim.PortAzimuth, "PITCH": sim.PortPitch,
	"FUEL": sim.PortFuel, "MASS": sim.PortMass,
	"SELECT": sim.PortScanSelect, "NEAREST": sim.PortScanNearest,
	"RELX": sim.PortScanRelX, "RELY": sim.PortScanRelY, "RELZ": sim.PortScanRelZ,
	"RELVX": sim.PortScanRelVX, "RELVY": sim.PortScanRelVY, "RELVZ": sim.PortScanRelVZ,
	"DIST": sim.PortScanDist,
	"ORE0": sim.PortScanOre, "ORE1": sim.PortScanOre + 1, "ORE2": sim.PortScanOre + 2, "ORE3": sim.PortScanOre + 3,
	"MINE": sim.PortMine, "CARGO": sim.PortCargo, "CARGOCAP": sim.PortCargoCap,
	"CARGO0": sim.PortCargoOre, "CARGO1": sim.PortCargoOre + 1, "CARGO2": sim.PortCargoOre + 2, "CARGO3": sim.PortCargoOre + 3,
	"STNX": sim.PortStnRelX, "STNY": sim.PortStnRelY, "STNZ": sim.PortStnRelZ,
	"STNVX": sim.PortStnRelVX, "STNVY": sim.PortStnRelVY, "STNVZ": sim.PortStnRelVZ,
	"SELL": sim.PortSell, "EARNED": sim.PortCredits,
	"UPNEW": sim.PortUplinkNew, "UPLEN": sim.PortUplinkLen,
	"MATHX": sim.PortMathX, "MATHY": sim.PortMathY, "MATHZ": sim.PortMathZ,
	"ATAN2": sim.PortMathAtan2, "HYPOT": sim.PortMathHypot, "NORM3": sim.PortMathNorm3,
}

func section(t *testing.T, md, from, to string) string {
	t.Helper()
	a := strings.Index(md, from)
	if a < 0 {
		t.Fatalf("manual has no %q", from)
	}
	b := len(md)
	if to != "" {
		b = a + strings.Index(md[a:], to)
	}
	return md[a:b]
}

func TestAppendixBMatchesSimulator(t *testing.T) {
	md := string(docs.Markdown)
	rows := regexp.MustCompile(`(?m)^0x([0-9A-F]{2})\s+(\w+)\s`).FindAllStringSubmatch(
		section(t, md, "# Appendix B", "# Appendix C"), -1)
	seen := map[string]bool{}
	for _, r := range rows {
		n, _ := strconv.ParseInt(r[1], 16, 32)
		want, ok := portValues[r[2]]
		if !ok || int(n) != want {
			t.Errorf("Appendix B: %s is 0x%s, simulator says %#x (known=%v)", r[2], r[1], want, ok)
		}
		seen[r[2]] = true
	}
	for name := range portValues {
		if !seen[name] {
			t.Errorf("Appendix B does not document port %s", name)
		}
	}
}

func readExample(t *testing.T, name string) string {
	t.Helper()
	b, err := os.ReadFile("../examples/programs/" + name)
	if err != nil {
		t.Fatal(err)
	}
	return strings.TrimRight(string(b), "\n")
}

func TestEquateFileMatchesSimulatorAndManual(t *testing.T) {
	ports := readExample(t, "ports.s")
	seen := map[string]bool{}
	for _, m := range regexp.MustCompile(`(?m)^\s*\.equ\s+P_(\w+)\s+0x([0-9A-F]{2})\b`).FindAllStringSubmatch(ports, -1) {
		n, _ := strconv.ParseInt(m[2], 16, 32)
		if want, ok := portValues[m[1]]; !ok || int(n) != want {
			t.Errorf("ports.s: P_%s = 0x%s, simulator says %#x (known=%v)", m[1], m[2], want, ok)
		}
		seen[m[1]] = true
	}
	for name := range portValues {
		if !seen[name] {
			t.Errorf("ports.s lacks P_%s", name)
		}
	}
	// Appendix C prints that file.
	if !strings.Contains(string(docs.Markdown), "```asm\n"+ports+"\n```") {
		t.Error("Appendix C is out of date with examples/programs/ports.s")
	}
}

func TestSampleProgramsMatchExamples(t *testing.T) {
	md := string(docs.Markdown)
	for _, name := range []string{"echo", "telemetry", "pursue"} {
		if !strings.Contains(md, "```asm\n"+readExample(t, name+".s")+"\n```") {
			t.Errorf("Chapter 9 listing of %s is out of date with examples/programs/%s.s", name, name)
		}
	}
}