package check

import (
	"fmt"
	"slices"
	"strings"
	"unicode/utf8"

	"git.novox.be/novox/mesh-sdk/go/delivery"
)

// MaxLine is the most characters a status's line has: the forge shows a status's description in a short space, and the full
// report is linked (ADR 0447 clause 3, ADR 0484 clause 7). A line that would be longer drops its lesser parts in a fixed
// order, and is cut last.
const MaxLine = 140

// seconds is a time in milliseconds in the unit a person reads: 350ms, 4.1s, 72s.
func seconds(ms int64) string {
	switch {
	case ms < 1000:
		return fmt.Sprintf("%dms", ms)
	case ms < 10000:
		return fmt.Sprintf("%.1fs", float64(ms)/1000)
	}
	return fmt.Sprintf("%ds", (ms+500)/1000)
}

func short12(s string) string {
	if len(s) > 12 {
		return s[:12]
	}
	return s
}

// firstFailed is what failed first, in words: a conflict, a refused step or a test, named before anything else.
func firstFailed(v delivery.Verdict) string {
	f := v.Failed
	switch {
	case f.Test != "":
		if w := firstWordsLine(f.Words); w != "" {
			return f.Test + ": " + w
		}
		return f.Test
	case f.Machine != "" && firstWordsLine(f.Words) != "":
		return f.Machine + ": " + firstWordsLine(f.Words)
	case f.Machine != "":
		return f.Machine
	}
	return firstWordsLine(f.Words)
}

// failedLines is everything a verdict names as failed, one line each: every failed test with its first line (issue
// 1921), or what failed first when the verdict names no list (a conflict, a refused step, an older verdict).
func failedLines(v delivery.Verdict) []string {
	if len(v.Failures) == 0 {
		if f := firstFailed(v); f != "" {
			return []string{f}
		}
		return nil
	}
	lines := make([]string, 0, len(v.Failures))
	for _, f := range v.Failures {
		lines = append(lines, firstFailed(delivery.Verdict{Failed: f}))
	}
	return lines
}

// failedCount is how many tests a verdict names as failed, the ones after delivery.MaxFailures counted too.
func failedCount(v delivery.Verdict) int {
	n := len(v.Failures)
	if n > delivery.MaxFailures {
		var more int
		if _, err := fmt.Sscanf(v.Failures[n-1].Test, "and %d more", &more); err == nil {
			return delivery.MaxFailures + more
		}
	}
	return n
}

// firstWordsLine is the first line of a failure's words: the words are several lines (issue 1901) and the status line one.
func firstWordsLine(w string) string { return firstLine(w) }

// pieces are the parts of a line, from the most to the least needed.
type pieces struct {
	head, commits, counts, shortCounts, times, shortTimes, over, builds, composition, shortComposition, group string
	// judged names the program that judged a change to a build module (ADR 0535 §5); never dropped.
	judged string
	// carried says, of a carried verdict, the commits it was carried from (ADR 0548 §8); never dropped.
	carried string
}

// pullKey names a pull request of a case: `<owner/repo>#<number>`.
func pullKey(p Pull) string { return fmt.Sprintf("%s#%d", p.Repository, p.Number) }

func (p pieces) join(drop int) string {
	parts := []string{p.head, p.commits, p.carried, p.counts, p.judged}
	switch {
	case drop < 3 && p.times != "":
		parts = append(parts, p.times)
	case drop == 3 && p.shortTimes != "":
		parts = []string{p.head, p.commits, p.carried, p.shortCounts, p.judged, p.shortTimes}
	}
	if p.over != "" {
		parts = append(parts, p.over)
	}
	if drop < 1 && p.builds != "" {
		parts = append(parts, p.builds)
	}
	if drop < 2 && p.group != "" {
		parts = append(parts, p.group)
	}
	switch {
	case drop >= 3 && p.shortComposition != "":
		parts = append(parts, p.shortComposition)
	case p.composition != "":
		parts = append(parts, p.composition)
	}
	return joinSet(parts...)
}

func levelWords(name string, r delivery.LevelResult) string {
	s := fmt.Sprintf("%s %d run, %d kept", name, r.Run, r.Kept)
	if r.Skipped > 0 {
		s += fmt.Sprintf(", %d skipped", r.Skipped)
	}
	return s
}

// compositionWords says the composition: not yet run, or once the assigner's check reports it (issue 1297) passed or
// failed, with the time it took and the machines it composed (issue 1300).
func compositionWords(c *delivery.Composition, took int64) string { return composition(c, took, false) }

// composition is compositionWords; short counts the machines and leaves the SDK commit to the report.
func composition(c *delivery.Composition, took int64, short bool) string {
	if c != nil && c.State == delivery.CompositionNotRun && c.Words != "" {
		return "composition not judged: " + c.Words
	}
	if c == nil || c.State == delivery.CompositionNotRun {
		return "composition not yet run"
	}
	in := ""
	if took > 0 {
		in = " in " + seconds(took)
	}
	on := ""
	if len(c.Machines) > 0 {
		machines := slices.Sorted(slices.Values(c.Machines))
		on = " on " + strings.Join(machines, ", ")
		switch {
		case len(machines) > 1 && short:
			on = fmt.Sprintf(" on %d machines", len(machines))
		case len(machines) > 1:
			on = fmt.Sprintf(" on %d machines: %s", len(machines), strings.Join(machines, ", "))
		}
	}
	switch {
	case c.State == delivery.CompositionPass && short:
		return "composition passed" + in + on // the SDK it composed with is in the report
	case c.State == delivery.CompositionPass:
		return "composition passed" + in + " with " + short12(c.SDK) + on
	}
	return "composition failed" + in + on + ": " + c.Words
}

func buildWords(builds []BuildNote) string {
	if len(builds) == 0 {
		return ""
	}
	parts := make([]string, len(builds))
	for i, b := range builds {
		parts[i] = b.Module + " " + b.State
	}
	return "builds: " + strings.Join(parts, ", ")
}

// carriedWords say the commits a verdict was carried from, for the line of pull request p (ADR 0548 §8): its own trunk's
// commit as twelve characters, a sibling's with its name before it; only those that moved, sorted. Empty when none did.
func carriedWords(from map[string]string, v delivery.Verdict, cs *Case, p Pull) string {
	var own string
	var others []string
	for r, old := range from {
		now, ok := v.Trunk[r]
		if cs != nil && !ok {
			now, ok = cs.Trunk[r]
		}
		if !ok {
			now = v.Beside[r]
		}
		if now == "" || now == old {
			continue
		}
		if strings.EqualFold(r, p.Repository) {
			own = short12(old)
			continue
		}
		name := r
		if i := strings.LastIndex(r, "/"); i >= 0 {
			name = r[i+1:]
		}
		others = append(others, name+" "+short12(old))
	}
	slices.Sort(others)
	if own != "" {
		others = append([]string{own}, others...)
	}
	return strings.Join(others, ", ")
}

// parts makes the pieces of the line of a pull request of a case.
func parts(v delivery.Verdict, cs *Case, p Pull, builds []BuildNote, slowest []string, judged map[string]string) pieces {
	var pc pieces
	pc.judged = judged[pullKey(p)]
	commits := short12(p.Head) + " on " + short12(p.Trunk)
	switch v.State {
	case delivery.VerdictRunning:
		pc.head = "checking " + commits
		if cs != nil && cs.CarriedFrom != nil {
			// Out of date and being carried to the new commit (ADR 0548 §6): pending, and saying so.
			pc.head = "being carried to " + commits
			if w := carriedWords(cs.CarriedFrom, v, cs, p); w != "" {
				pc.carried = "from " + w
			}
		}
	case delivery.VerdictPass:
		pc.head = "pass " + commits
		if w := carriedWords(v.CarriedFrom, v, cs, p); w != "" {
			pc.carried = "carried from " + w // the counts that follow say what the carry ran and kept
		}
	default:
		pc.head = "failed: " + firstFailed(v)
		if n := failedCount(v); n > 1 {
			pc.head = fmt.Sprintf("failed (%d tests): %s", n, firstFailed(v))
		}
		pc.commits = commits
	}
	var counts []string
	for _, level := range []string{delivery.LevelUnit, delivery.LevelIntegration} {
		if r, ok := v.Levels[level]; ok {
			counts = append(counts, levelWords(level, r))
		}
	}
	pc.counts = strings.Join(counts, " | ")
	var short []string
	for _, level := range []string{delivery.LevelUnit, delivery.LevelIntegration} {
		if r, ok := v.Levels[level]; ok {
			name := map[string]string{delivery.LevelUnit: "unit", delivery.LevelIntegration: "int"}[level]
			w := fmt.Sprintf("%s %d run %d kept", name, r.Run, r.Kept)
			if r.Skipped > 0 {
				w += fmt.Sprintf(" %d skipped", r.Skipped)
			}
			short = append(short, w)
		}
	}
	pc.shortCounts = strings.Join(short, " | ")
	if v.State != delivery.VerdictRunning {
		t := v.Took
		var times []string
		for _, x := range []struct {
			name string
			ms   int64
		}{{"queue", t.Queue}, {"clone", t.Clone}, {"lint", t.Lint}, {"unit", t.Unit}, {"int setup", t.IntegrationSetup}, {"int run", t.IntegrationRun}} {
			if x.ms > 0 {
				times = append(times, x.name+" "+seconds(x.ms))
			}
		}
		if len(times) > 0 {
			pc.times = strings.Join(times, ", ")
		}
		// The compact form for a line that is too long: the parts that dominate, the integration level's setup and run as one.
		short = short[:0:0]
		if t.Clone > 0 {
			short = append(short, "clone "+seconds(t.Clone))
		}
		if t.Lint > 0 {
			short = append(short, "lint "+seconds(t.Lint))
		}
		if t.Unit > 0 {
			short = append(short, "unit "+seconds(t.Unit))
		}
		switch {
		case t.IntegrationSetup > 0 && t.IntegrationRun > 0:
			short = append(short, "int "+seconds(t.IntegrationSetup)+"+"+seconds(t.IntegrationRun))
		case t.IntegrationRun > 0:
			short = append(short, "int "+seconds(t.IntegrationRun))
		}
		pc.shortTimes = strings.Join(short, " ")
	}
	if len(v.OverBound) > 0 {
		pc.over = "over bound: " + strings.Join(v.OverBound, ", ")
		if len(slowest) > 0 {
			pc.over += " (slowest " + strings.Join(slowest, ", ") + ")"
		}
	}
	pc.builds = buildWords(builds)
	if v.State != delivery.VerdictRunning {
		pc.composition = compositionWords(v.Composition, v.Took.Composition)
		pc.shortComposition = composition(v.Composition, v.Took.Composition, true)
	}
	if cs != nil && len(cs.Pulls) > 1 {
		pc.group = fmt.Sprintf("group %s of %d pull requests", cs.Group, len(cs.Pulls))
		if v.State != delivery.VerdictPass {
			pc.group = fmt.Sprintf("%s#%d in group %s", p.Repository, p.Number, cs.Group)
		}
	}
	return pc
}

// Report is the full line of a pull request's status, with no limit: what the read tools and the full report say.
func Report(v delivery.Verdict, cs *Case, p Pull, builds []BuildNote, slowest []string, judged map[string]string) string {
	return parts(v, cs, p, builds, slowest, judged).join(0)
}

// Line is the words of a status for one pull request of a case (ADR 0447 clause 3, ADR 0484 clause 7): the verdict first (a
// failure names the conflict, the refused step or the test before anything), the head and the trunk commit as twelve
// characters each, the tests run, kept and skipped per level, the time of each part, a level over its bound with its slowest
// tests, the builds of the touched modules, and that the composition was not yet run; for a change to a build module, the
// program that judged it (judged, by pullKey; ADR 0535 §5). It is at most MaxLine characters: the
// builds, then the group drop first, then the times are given in their compact form, then dropped, and the line is cut at last.
// The program that judged is never dropped: a line naming it gives the counts in their compact form, then drops them and
// what follows, and is cut in its first part rather than lose it.
func Line(v delivery.Verdict, cs *Case, p Pull, builds []BuildNote, slowest []string, judged map[string]string) string {
	pc := parts(v, cs, p, builds, slowest, judged)
	for drop := 0; drop <= 4; drop++ {
		if s := pc.join(drop); utf8.RuneCountInString(s) <= MaxLine {
			return s
		}
	}
	if pc.judged != "" {
		for _, counts := range []string{pc.shortCounts, ""} {
			if s := joinSet(pc.head, pc.commits, counts, pc.judged); utf8.RuneCountInString(s) <= MaxLine {
				return s
			}
		}
		rest := " | " + joinSet(pc.commits, pc.judged)
		room := MaxLine - utf8.RuneCountInString(rest) - 1
		if head := []rune(pc.head); room > 0 && len(head) > room {
			return string(head[:room]) + "…" + rest
		}
	}
	runes := []rune(pc.join(4))
	return string(runes[:MaxLine-1]) + "…"
}

// joinSet joins the parts that are not empty.
func joinSet(parts ...string) string {
	out := make([]string, 0, len(parts))
	for _, s := range parts {
		if s != "" {
			out = append(out, s)
		}
	}
	return strings.Join(out, " | ")
}