package main

import (
	"encoding/json"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

type mraidIssue struct {
	ID        string `json:"id"`
	Severity  string `json:"severity"`
	Title     string `json:"title"`
	Detail    string `json:"detail"`
	Line      int    `json:"line,omitempty"`
	Reference string `json:"reference"`
}

type mraidResult struct {
	File   string       `json:"file"`
	OK     bool         `json:"ok"`
	Issues []mraidIssue `json:"issues"`
}

type mraidRule struct {
	ID        string
	Severity  string
	Title     string
	Detail    string
	Reference string
	Test      func(mraidContext, mraidRule) *mraidIssue
}

type mraidContext struct {
	HTML           string
	ScriptText     string
	MraidCallLines map[string]int
}

func MraidPage(w http.ResponseWriter, r *http.Request) {
	body := `
<h2>MRAID Checker</h2>
<p class="hint">Static checks for AppLovin, ironSource, and Unity HTML builds based on MRAID 3.0 requirements and best practices from mraidDocuments/.</p>
<div style="display:flex;gap:8px;align-items:center;margin-bottom:8px;">
  <input id="folder" type="text" placeholder="Folder to scan recursively..." style="flex:1;" />
  <button id="pickFolder">Browse Folder...</button>
  <button id="pickFiles">Pick Files...</button>
  <button id="scan">Scan</button>
</div>
<div id="selection" class="hint"></div>
<div id="status" style="margin-top:8px;"></div>
<div id="results" style="margin-top:8px;"></div>

<style>
  .row-result { padding:8px 0; border-bottom:1px solid #333; }
  .file-head { display:flex; gap:8px; align-items:baseline; font-family:Consolas, monospace; font-size:12px; }
  .mark { width:20px; flex-shrink:0; font-weight:bold; }
  .mark.ok { color:#3fb950; } .mark.bad { color:#f85149; }
  .file-name { word-break:break-all; }
  .counts { opacity:0.7; margin-left:auto; white-space:nowrap; }
  .issues { margin:6px 0 0 28px; padding:0; }
  .issue { list-style:none; margin:6px 0; }
  .badge { display:inline-block; min-width:82px; margin-right:6px; padding:1px 5px; border-radius:3px; font-size:11px; text-align:center; }
  .requirement { color:#ffb4ad; background:rgba(248,81,73,0.18); }
  .best-practice { color:#ffd580; background:rgba(210,153,34,0.18); }
  .issue-title { font-weight:600; }
  .issue-detail { opacity:0.72; margin-top:2px; }
  .summary { opacity:0.85; margin-bottom:6px; }
</style>

<script>
const folderEl = document.getElementById('folder');
const statusEl = document.getElementById('status');
const resultsEl = document.getElementById('results');
const selectionEl = document.getElementById('selection');
let pickedFiles = [];
function clearFiles(){ pickedFiles = []; selectionEl.textContent = ''; }
function escapeText(value){ return String(value).replace(/[&<>"']/g, ch => ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#39;'}[ch])); }
folderEl.addEventListener('input', clearFiles);

document.getElementById('pickFolder').addEventListener('click', async () => {
  const r = await fetch('/api/mraid/pickFolder', { method: 'POST' });
  const j = await r.json();
  if (j.path) { folderEl.value = j.path; clearFiles(); }
});
document.getElementById('pickFiles').addEventListener('click', async () => {
  const r = await fetch('/api/mraid/pickFiles', { method: 'POST' });
  const j = await r.json();
  if (j.paths && j.paths.length) {
    pickedFiles = j.paths;
    folderEl.value = '';
    selectionEl.textContent = pickedFiles.length + ' file(s) selected';
  }
});
document.getElementById('scan').addEventListener('click', async () => {
  statusEl.textContent = 'Scanning...';
  resultsEl.innerHTML = '';
  let payload;
  if (pickedFiles.length) payload = { files: pickedFiles };
  else {
    const folder = folderEl.value.trim();
    if (!folder) { statusEl.textContent = 'Pick a folder or files first.'; return; }
    payload = { folder };
  }
  const r = await fetch('/api/mraid/scan', { method:'POST', headers:{'Content-Type':'application/json'}, body: JSON.stringify(payload) });
  const j = await r.json();
  if (j.error) { statusEl.textContent = 'Error: ' + j.error; return; }
  const total = j.results.length;
  const withIssues = j.results.filter(r => !r.ok).length;
  const requirements = j.results.reduce((n, r) => n + r.issues.filter(i => i.severity === 'requirement').length, 0);
  const bestPractices = j.results.reduce((n, r) => n + r.issues.filter(i => i.severity === 'best-practice').length, 0);
  const skipped = Number(j.skipped || 0);
  const skippedText = skipped ? ' Skipped ' + skipped + ' non-target HTML file(s).' : '';
  statusEl.innerHTML = '<div class="summary">Scanned ' + total + ' AppLovin/ironSource/Unity HTML file(s). ' + withIssues + ' file(s) need review. ' + requirements + ' requirement issue(s), ' + bestPractices + ' best-practice warning(s).' + skippedText + '</div>';
  resultsEl.innerHTML = '';
  for (const rr of j.results) {
    const reqCount = rr.issues.filter(i => i.severity === 'requirement').length;
    const bpCount = rr.issues.filter(i => i.severity === 'best-practice').length;
    const row = document.createElement('div');
    row.className = 'row-result';
    row.innerHTML = '<div class="file-head"><span class="mark ' + (rr.ok ? 'ok' : 'bad') + '">' + (rr.ok ? 'OK' : 'X') + '</span><span class="file-name">' + escapeText(rr.file) + '</span><span class="counts">' + reqCount + ' req / ' + bpCount + ' bp</span></div>';
    if (!rr.ok) {
      const list = document.createElement('ul');
      list.className = 'issues';
      for (const i of rr.issues) {
        const item = document.createElement('li');
        item.className = 'issue';
        const line = i.line ? ' line ' + i.line + ':' : '';
        item.innerHTML = '<span class="badge ' + i.severity + '">' + escapeText(i.severity) + '</span><span class="issue-title">' + escapeText(line + ' ' + i.title) + '</span><div class="issue-detail">' + escapeText(i.detail) + '</div>';
        list.appendChild(item);
      }
      row.appendChild(list);
    }
    resultsEl.appendChild(row);
  }
});
</script>
`
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	_, _ = w.Write([]byte(Page("/mraid", "MRAID Checker", body)))
}

func MraidPickFolder(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, map[string]any{"path": PickFolder("Select folder to scan", "")})
}

func MraidPickFiles(w http.ResponseWriter, r *http.Request) {
	paths := PickFiles("Select HTML files", []FileFilter{{Name: "HTML", Extensions: []string{"html", "htm"}}}, true, "")
	writeJSON(w, map[string]any{"paths": paths})
}

func MraidScan(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Folder string   `json:"folder"`
		Files  []string `json:"files"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeJSON(w, map[string]any{"results": []mraidResult{}, "error": err.Error()})
		return
	}

	var targets []string
	var baseDir string
	skipped := 0
	if len(req.Files) > 0 {
		var existing []string
		for _, f := range req.Files {
			if fileExists(f) {
				existing = append(existing, f)
			}
		}
		for _, f := range existing {
			if isSupportedMraidBuild(f) {
				targets = append(targets, f)
			}
		}
		skipped = len(existing) - len(targets)
		if len(targets) > 0 {
			baseDir = commonBaseDir(targets)
		}
	} else if req.Folder != "" && fileExists(req.Folder) {
		all := collectHTMLFiles(req.Folder)
		for _, f := range all {
			if isSupportedMraidBuild(f) {
				targets = append(targets, f)
			}
		}
		skipped = len(all) - len(targets)
		baseDir = req.Folder
	} else {
		writeJSON(w, map[string]any{"results": []mraidResult{}, "error": "Pick a folder or files first"})
		return
	}
	if len(targets) == 0 {
		writeJSON(w, map[string]any{"results": []mraidResult{}, "skipped": skipped, "error": "No AppLovin, ironSource, or Unity HTML builds were found."})
		return
	}

	results := []mraidResult{}
	for _, file := range targets {
		data, err := os.ReadFile(file)
		if err != nil {
			continue
		}
		issues := checkMraid(string(data))
		display := file
		if baseDir != "" {
			if rel, err := filepath.Rel(baseDir, file); err == nil && rel != "" {
				display = rel
			} else {
				display = filepath.Base(file)
			}
		}
		results = append(results, mraidResult{File: display, OK: len(issues) == 0, Issues: issues})
	}
	writeJSON(w, map[string]any{"results": results, "skipped": skipped})
}

var (
	mraidScriptRx       = regexp.MustCompile(`(?is)<script\b[^>]*>(.*?)</script>`)
	mraidCallRx         = regexp.MustCompile(`(?i)\bmraid\s*\.\s*([a-zA-Z_$][\w$]*)\s*\(`)
	mraidBuildNameRx    = regexp.MustCompile(`(?i)(^|[/._ -])(al|applovin|app-lovin|is|iron.?source|un|unity|unityads|unity-ads)([/._ -]|$)`)
	mraidReferenceRx    = regexp.MustCompile(`(?i)\bmraid\b`)
	mraidWindowOpenRx   = regexp.MustCompile(`(?i)\bwindow\s*\.\s*open\s*\(`)
	mraidLocationNavRx  = regexp.MustCompile(`(?i)\blocation\s*\.\s*(href|assign|replace)\b`)
	mraidCloseUiRx      = regexp.MustCompile(`(?i)\b(close|dismiss|skip)\b`)
	mraidLoadingLeftRx  = regexp.MustCompile(`(?i)mraid\s*\.\s*getState\s*\(\s*\)\s*={0,2}\s*['"]loading['"]`)
	mraidLoadingRightRx = regexp.MustCompile(`(?i)['"]loading['"]\s*={0,2}\s*mraid\s*\.\s*getState\s*\(\s*\)`)
)

const mraidReference = "MRAID 3.0 specification and MRAID 3.0 Best Practices Guide in mraidDocuments/"

func isSupportedMraidBuild(filePath string) bool {
	normalized := strings.ReplaceAll(strings.ToLower(filePath), `\`, `/`)
	return mraidBuildNameRx.MatchString(normalized)
}

func checkMraid(htmlSrc string) []mraidIssue {
	ctx := mraidContext{
		HTML:           htmlSrc,
		ScriptText:     extractMraidScriptText(htmlSrc),
		MraidCallLines: collectMraidCallLines(htmlSrc),
	}
	var out []mraidIssue
	for _, rule := range mraidRules {
		if found := rule.Test(ctx, rule); found != nil {
			out = append(out, *found)
		}
	}
	if out == nil {
		out = []mraidIssue{}
	}
	return out
}

func extractMraidScriptText(htmlSrc string) string {
	var parts []string
	for _, m := range mraidScriptRx.FindAllStringSubmatch(htmlSrc, -1) {
		parts = append(parts, m[1])
	}
	return strings.Join(parts, "\n")
}

func collectMraidCallLines(htmlSrc string) map[string]int {
	out := map[string]int{}
	for idx, line := range strings.Split(htmlSrc, "\n") {
		for _, m := range mraidCallRx.FindAllStringSubmatch(line, -1) {
			if _, ok := out[m[1]]; !ok {
				out[m[1]] = idx + 1
			}
		}
	}
	return out
}

func mraidHasReference(ctx mraidContext) bool { return mraidReferenceRx.MatchString(ctx.HTML) }
func mraidHasCall(ctx mraidContext, method string) bool {
	_, ok := ctx.MraidCallLines[method]
	return ok
}
func mraidLine(ctx mraidContext, method string) int { return ctx.MraidCallLines[method] }

func mraidHasEventListener(ctx mraidContext, eventName string) bool {
	rx := regexp.MustCompile(`(?i)mraid\s*\.\s*addEventListener\s*\(\s*['"]` + regexp.QuoteMeta(eventName) + `['"]`)
	return rx.MatchString(ctx.ScriptText)
}

func mraidHasSupportCheck(ctx mraidContext, feature string) bool {
	rx := regexp.MustCompile(`(?i)mraid\s*\.\s*supports\s*\(\s*['"]` + regexp.QuoteMeta(feature) + `['"]`)
	return rx.MatchString(ctx.ScriptText)
}

func mraidHasReadyGate(ctx mraidContext) bool {
	return mraidHasEventListener(ctx, "ready") || mraidLoadingLeftRx.MatchString(ctx.ScriptText) || mraidLoadingRightRx.MatchString(ctx.ScriptText)
}

func mraidIssueFrom(rule mraidRule, line int) *mraidIssue {
	found := mraidIssue{ID: rule.ID, Severity: rule.Severity, Title: rule.Title, Detail: rule.Detail, Reference: rule.Reference}
	if line > 0 {
		found.Line = line
	}
	return &found
}

var mraidRules = []mraidRule{
	{ID: "mraid-reference", Severity: "requirement", Title: "MRAID API reference not found", Detail: "Playable HTML should use the injected mraid object when it depends on an MRAID container.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if mraidHasReference(ctx) {
			return nil
		}
		return mraidIssueFrom(rule, 0)
	}},
	{ID: "ready-gate", Severity: "requirement", Title: "MRAID ready state is not guarded", Detail: "Gate ad startup behind mraid.ready, or call startup immediately only when mraid.getState() is not loading.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if !mraidHasReference(ctx) || mraidHasReadyGate(ctx) {
			return nil
		}
		return mraidIssueFrom(rule, 0)
	}},
	{ID: "error-listener", Severity: "best-practice", Title: "No MRAID error listener found", Detail: "Listen for mraid error events so unsupported or failed MRAID calls can be logged or handled gracefully.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if !mraidHasReference(ctx) || mraidHasEventListener(ctx, "error") {
			return nil
		}
		return mraidIssueFrom(rule, 0)
	}},
	{ID: "viewability", Severity: "best-practice", Title: "Viewability handling not found", Detail: "Use mraid.isViewable() and/or viewableChange before starting animation, audio, video, or timers.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if !mraidHasReference(ctx) || mraidHasCall(ctx, "isViewable") || mraidHasEventListener(ctx, "viewableChange") || mraidHasEventListener(ctx, "exposureChange") {
			return nil
		}
		return mraidIssueFrom(rule, 0)
	}},
	{ID: "open-api", Severity: "requirement", Title: "Browser navigation used instead of mraid.open", Detail: "Use mraid.open(url) for click-through navigation inside an MRAID ad container.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if (mraidWindowOpenRx.MatchString(ctx.ScriptText) || mraidLocationNavRx.MatchString(ctx.ScriptText)) && !mraidHasCall(ctx, "open") {
			return mraidIssueFrom(rule, 0)
		}
		return nil
	}},
	{ID: "close-api", Severity: "best-practice", Title: "No mraid.close call found", Detail: "If the creative renders its own close control, wire that control to mraid.close().", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if mraidCloseUiRx.MatchString(ctx.HTML) && !mraidHasCall(ctx, "close") {
			return mraidIssueFrom(rule, 0)
		}
		return nil
	}},
	{ID: "expand-support", Severity: "requirement", Title: "mraid.expand used without supports check", Detail: "Check mraid.supports(\"expand\") before using expand behavior.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if mraidHasCall(ctx, "expand") && !mraidHasSupportCheck(ctx, "expand") {
			return mraidIssueFrom(rule, mraidLine(ctx, "expand"))
		}
		return nil
	}},
	{ID: "resize-support", Severity: "requirement", Title: "mraid.resize used without supports check", Detail: "Check mraid.supports(\"resize\") before using resize behavior.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if mraidHasCall(ctx, "resize") && !mraidHasSupportCheck(ctx, "resize") {
			return mraidIssueFrom(rule, mraidLine(ctx, "resize"))
		}
		return nil
	}},
	{ID: "orientation-support", Severity: "best-practice", Title: "Orientation properties set without supports check", Detail: "Check mraid.supports(\"orientation\") before requiring orientation behavior.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		if mraidHasCall(ctx, "setOrientationProperties") && !mraidHasSupportCheck(ctx, "orientation") {
			return mraidIssueFrom(rule, mraidLine(ctx, "setOrientationProperties"))
		}
		return nil
	}},
	{ID: "size-change", Severity: "best-practice", Title: "No sizeChange listener found", Detail: "Listen for sizeChange when layout depends on container size, resize, expand, or orientation behavior.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		depends := mraidHasCall(ctx, "getMaxSize") || mraidHasCall(ctx, "getScreenSize") || mraidHasCall(ctx, "resize") || mraidHasCall(ctx, "expand") || mraidHasCall(ctx, "setOrientationProperties")
		if depends && !mraidHasEventListener(ctx, "sizeChange") {
			return mraidIssueFrom(rule, 0)
		}
		return nil
	}},
	{ID: "state-change", Severity: "best-practice", Title: "No stateChange listener found", Detail: "Listen for stateChange when using expand, resize, close, or other state-changing container behavior.", Reference: mraidReference, Test: func(ctx mraidContext, rule mraidRule) *mraidIssue {
		changes := mraidHasCall(ctx, "expand") || mraidHasCall(ctx, "resize") || mraidHasCall(ctx, "close")
		if changes && !mraidHasEventListener(ctx, "stateChange") {
			return mraidIssueFrom(rule, 0)
		}
		return nil
	}},
}