package buildstep

// The reader of `node --test` under its TAP reporter (issue 1901's thorough fix; first written in mesh-build-node by
// fix-1901ts): each failing test with its name, its file, its cause and its own block, never a passing line of an
// earlier file, which is what node's default reporter left the first fifteen lines of.

import (
	"regexp"
	"strings"
)

// NodeTestOptions is the NODE_OPTIONS a build module runs a package's test script with: node's TAP reporter, written to
// the file dest, so whatever the script prints on its own output the report is whole and machine-readable. A script
// that names a reporter of its own makes node refuse the run loudly ("--test-reporter must match the number of
// --test-reporter-destination"), never quietly.
func NodeTestOptions(dest string) string {
	return "--test-reporter=tap --test-reporter-destination=" + dest
}

var ansiEscape = regexp.MustCompile("\x1b\\[[0-9;]*m")

func stripANSI(s string) string { return ansiEscape.ReplaceAllString(s, "") }

// ReadTAP reads the failing tests of a `node --test` run: report is what the TAP reporter wrote (NodeTestOptions'
// file), console the script's own stdout and stderr, script the name of the script that ran and dir the package's
// directory, which a test's file is made relative to. A suite that failed only because a test inside it did is not
// reported twice. A test file that did not load (a syntax error, a crash, an error after its test ended) takes its
// cause from the lines node wrote before it. When the report holds no failing test (node itself failed, or the script
// failed before its tests ran: a build, a reporter refused) the failure is the console's (ConsoleFailure).
func ReadTAP(pkg, script, dir, report, console string) []Failure {
	var failed []Failure
	all := strings.Split(stripANSI(strings.ReplaceAll(report, "\r\n", "\n")), "\n")
	prev := 0 // the line after the last test block: what the run wrote since belongs to the next test
	for i := 0; i < len(all); i++ {
		name, ok := tapNotOk(all[i])
		if !ok {
			continue
		}
		indent := len(all[i]) - len(strings.TrimLeft(all[i], " "))
		block := []string{strings.TrimSpace(all[i])}
		fields := map[string]string{}
		var key string
		inYAML := false
		j := i + 1
		for ; j < len(all); j++ {
			t := strings.TrimSpace(all[j])
			if !inYAML {
				if t == "---" {
					inYAML = true
					continue
				}
				break
			}
			if t == "..." {
				j++
				break
			}
			block = append(block, strings.TrimRight(all[j], " \t"))
			if k, v, found := tapKey(all[j], indent); found {
				key = k
				if v != "|-" && v != "|" {
					fields[k] = strings.Trim(v, "'")
				}
			} else if key != "" && fields[key] == "" && t != "" {
				fields[key] = t // the first line of a block scalar
			}
		}
		from := prev
		i, prev = j-1, j
		if fields["failureType"] == "subtestsFailed" {
			continue
		}
		cause := fields["error"]
		if cause == "test failed" || cause == "" {
			// a file that did not load, or an error after a test ended: node says only "test failed" and wrote the
			// error as comment lines before it
			var own []string
			for _, l := range all[from:i] {
				if t := strings.TrimSpace(l); strings.HasPrefix(t, "# ") && !strings.HasPrefix(t, "# Subtest") {
					own = append(own, strings.TrimPrefix(t, "# "))
				}
			}
			for _, l := range own {
				if strings.Contains(l, "Error") {
					cause = l
					break
				}
			}
			if cause == "" && len(own) > 0 {
				cause = own[0]
			}
			block = append(own, block...)
		}
		if cause == "" {
			cause = fields["failureType"]
		}
		if cause == "" {
			cause = "the test failed and node said no error"
		}
		cause = CutLine(cause)
		file := strings.TrimPrefix(fields["location"], "file://")
		if dir != "" {
			file = strings.TrimPrefix(file, strings.TrimSuffix(dir, "/")+"/")
		}
		failed = append(failed, Failure{Package: pkg, Test: name, File: file, Cause: cause, Output: Clip(block, cause)})
	}
	if len(failed) > 0 {
		return failed
	}
	var comments []string
	for _, l := range all {
		if t := strings.TrimSpace(l); strings.HasPrefix(t, "# ") && !strings.HasPrefix(t, "# Subtest") && !tapCount(t) {
			comments = append(comments, strings.TrimPrefix(t, "# "))
		}
	}
	return []Failure{ConsoleFailure(pkg, script, strings.Join(comments, "\n")+"\n"+console)}
}

// tapCount says a comment is TAP's closing count ("# tests 3", "# pass 2", "# duration_ms 1.2").
func tapCount(t string) bool {
	for _, w := range []string{"tests", "suites", "pass", "fail", "cancelled", "skipped", "todo", "duration_ms"} {
		if strings.HasPrefix(t, "# "+w+" ") {
			return true
		}
	}
	return false
}

// tapNotOk is the test name of a "not ok N - name" line, indented or not; a TODO or SKIP directive fails nothing.
func tapNotOk(l string) (string, bool) {
	t := strings.TrimSpace(l)
	rest, ok := strings.CutPrefix(t, "not ok ")
	if !ok {
		return "", false
	}
	if u := strings.ToUpper(rest); strings.Contains(u, " # TODO") || strings.Contains(u, " # SKIP") {
		return "", false
	}
	if _, after, found := strings.Cut(rest, " - "); found {
		rest = after
	}
	return strings.TrimSpace(rest), true
}

// tapKey is "key: value" of a field of a TAP block, whose lines sit two spaces deeper than their "not ok" line; a deeper
// line is part of a block scalar (an error's lines, a stack).
func tapKey(l string, indent int) (key, val string, ok bool) {
	t := strings.TrimLeft(l, " ")
	if len(l)-len(t) != indent+2 {
		return "", "", false
	}
	k, v, found := strings.Cut(t, ": ")
	if !found {
		if k, found = strings.CutSuffix(t, ":"); !found {
			return "", "", false
		}
	}
	if k == "" || strings.ContainsAny(k, " ()/") {
		return "", "", false
	}
	return k, strings.TrimSpace(v), true
}