package webui

import (
	"context"
	"database/sql"
	"fmt"
	"html"
	"io"
	"strings"
	"time"

	"github.com/a-h/templ"

	"satoru/internal/store"
)

type RuntimeCheck struct {
	Name      string
	Installed bool
	Details   string
}

type WorkflowStage struct {
	Title       string
	Description string
}

type DashboardData struct {
	Now            time.Time
	User           store.User
	Sites          []store.Site
	RuntimeChecks  []RuntimeCheck
	WorkflowStages []WorkflowStage
	FlashMessage   string
}

func Dashboard(data DashboardData) templ.Component {
	return templ.ComponentFunc(func(_ context.Context, w io.Writer) error {
		role := "Operator"
		if data.User.IsAdmin {
			role = "Admin"
		}

		var checks strings.Builder
		for _, c := range data.RuntimeChecks {
			status := "missing"
			if c.Installed {
				status = "installed"
			}
			checks.WriteString(fmt.Sprintf(`<li class="status %s"><strong>%s</strong><span>%s</span></li>`,
				status,
				html.EscapeString(c.Name),
				html.EscapeString(c.Details)))
		}

		var flows strings.Builder
		for _, s := range data.WorkflowStages {
			flows.WriteString(fmt.Sprintf(`<li class="workflow-step"><strong>%s</strong><p>%s</p></li>`,
				html.EscapeString(s.Title),
				html.EscapeString(s.Description)))
		}

		var sites strings.Builder
		if len(data.Sites) == 0 {
			sites.WriteString(`<p class="muted">No sites added yet. Add your first Linux SSH site below.</p>`)
		}
		for _, site := range data.Sites {
			last := "Never run"
			if site.LastRunAt.Valid {
				last = site.LastRunAt.Time.Local().Format(time.RFC1123)
			}
			runStatus := "pending"
			if site.LastRunStatus.Valid {
				runStatus = site.LastRunStatus.String
			}
			runOutput := "(no output yet)"
			if site.LastRunOutput.Valid && strings.TrimSpace(site.LastRunOutput.String) != "" {
				runOutput = site.LastRunOutput.String
			}
			scanState := "pending"
			if site.LastScanState.Valid && site.LastScanState.String != "" {
				scanState = site.LastScanState.String
			}
			lastScan := "Never"
			if site.LastScanAt.Valid {
				lastScan = site.LastScanAt.Time.Local().Format(time.RFC1123)
			}
			scanNotes := "No scan yet."
			if site.LastScanNotes.Valid && site.LastScanNotes.String != "" {
				scanNotes = site.LastScanNotes.String
			}

			var targets strings.Builder
			if len(site.Targets) == 0 {
				targets.WriteString(`<li><span class="pill pending">none</span> <code>(no targets)</code></li>`)
			}
			for _, t := range site.Targets {
				sizeOrErr := "size pending"
				if t.LastError.Valid && t.LastError.String != "" {
					sizeOrErr = "error: " + t.LastError.String
				} else if t.LastSizeByte.Valid {
					sizeOrErr = formatBytes(t.LastSizeByte.Int64)
				}
				targets.WriteString(fmt.Sprintf(`<li><span class="pill %s">%s</span> <code>%s</code><span class="muted inline">%s</span></li>`,
					targetModeClass(t.Mode),
					html.EscapeString(targetModeLabel(t.Mode)),
					html.EscapeString(t.Path),
					html.EscapeString(sizeOrErr)))
			}

			sites.WriteString(fmt.Sprintf(`
<article class="site-card">
  <div class="site-head">
    <h3>%s@%s:%d</h3>
    <form method="post" action="/sites/%d/run">
      <button class="button" type="submit">Run</button>
    </form>
  </div>
  <p class="muted">Backup targets:</p>
  <ul class="target-list">%s</ul>
  <p class="muted">Scan: <span class="pill %s">%s</span> · Last: %s · Next: %s</p>
  <p class="muted">%s</p>
  <p class="muted">Last run: %s</p>
  <p class="muted">Status: <span class="pill %s">%s</span></p>
  <pre class="output">%s</pre>
</article>`,
				html.EscapeString(site.SSHUser),
				html.EscapeString(site.Host),
				site.Port,
				site.ID,
				targets.String(),
				html.EscapeString(scanState),
				html.EscapeString(scanState),
				html.EscapeString(lastScan),
				html.EscapeString(timeUntilNextScan(data.Now, site.LastScanAt)),
				html.EscapeString(scanNotes),
				html.EscapeString(last),
				html.EscapeString(runStatus),
				html.EscapeString(runStatus),
				html.EscapeString(runOutput),
			))
		}

		flash := ""
		if data.FlashMessage != "" {
			flash = fmt.Sprintf(`<p class="notice">%s</p>`, html.EscapeString(formatFlash(data.FlashMessage)))
		}

		_, err := io.WriteString(w, fmt.Sprintf(`<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Satoru Dashboard</title>
    <link rel="stylesheet" href="/static/app.css" />
  </head>
  <body>
    <main class="card dashboard-card">
      <div class="row split">
        <div>
          <p class="eyebrow">Satoru</p>
          <h1>Managed Sites Overview</h1>
          <p class="muted">Signed in as <strong>%s</strong> (%s).</p>
        </div>
        <div class="row">
          <a class="button ghost" href="/account/password">Change password</a>
          <form method="post" action="/signout"><button class="button ghost" type="submit">Sign out</button></form>
        </div>
      </div>
      %s
      <section>
        <h2>Host Runtime Status</h2>
        <ul class="status-list">%s</ul>
      </section>
      <section>
        <h2>Planned Workflow</h2>
        <ol class="workflow">%s</ol>
      </section>
      <section>
        <h2>Add Site</h2>
        <form class="grid-2" method="post" action="/sites">
          <label class="stack"><span>SSH User</span><input name="ssh_user" required /></label>
          <label class="stack"><span>Server</span><input name="host" placeholder="host or ip" required /></label>
          <label class="stack"><span>Port</span><input type="number" name="port" min="1" max="65535" value="22" required /></label>
          <label class="stack"><span>Directory paths (one per line)</span><textarea name="directory_paths" placeholder="/var/www&#10;/etc/nginx" rows="4"></textarea></label>
          <label class="stack"><span>SQLite DB paths (will dump, one per line)</span><textarea name="sqlite_paths" placeholder="/srv/app/db/app.sqlite3" rows="4"></textarea></label>
          <button class="button" type="submit">Add site</button>
        </form>
      </section>
      <section>
        <h2>Managed Sites</h2>
        %s
      </section>
    </main>
  </body>
</html>`,
			html.EscapeString(data.User.Username),
			html.EscapeString(role),
			flash,
			checks.String(),
			flows.String(),
			sites.String(),
		))
		return err
	})
}

func formatFlash(code string) string {
	switch code {
	case "site-added":
		return "Site added."
	case "site-ran":
		return "Run completed."
	case "site-invalid":
		return "SSH user, host, and at least one target path are required."
	case "site-invalid-path":
		return "Target paths must be absolute Linux paths starting with '/'."
	case "site-invalid-port":
		return "Port must be an integer between 1 and 65535."
	case "password-updated":
		return "Password updated."
	default:
		return code
	}
}

func targetModeLabel(mode string) string {
	if mode == "sqlite_dump" {
		return "sqlite dump"
	}
	return "directory"
}

func targetModeClass(mode string) string {
	if mode == "sqlite_dump" {
		return "sqlite"
	}
	return "ok"
}

func formatBytes(v int64) string {
	if v < 1024 {
		return fmt.Sprintf("%d B", v)
	}
	units := []string{"KB", "MB", "GB", "TB"}
	value := float64(v)
	for _, u := range units {
		value /= 1024
		if value < 1024 {
			return fmt.Sprintf("%.1f %s", value, u)
		}
	}
	return fmt.Sprintf("%.1f PB", value/1024)
}

func timeUntilNextScan(now time.Time, lastScan sql.NullTime) string {
	if !lastScan.Valid {
		return "due now"
	}
	next := lastScan.Time.Add(24 * time.Hour)
	if !next.After(now) {
		return "due now"
	}
	d := next.Sub(now).Round(time.Minute)
	h := int(d.Hours())
	m := int(d.Minutes()) % 60
	if h == 0 {
		return fmt.Sprintf("%dm", m)
	}
	return fmt.Sprintf("%dh %dm", h, m)
}