import React, { useEffect, useState } from "react";

import { Box, Button, Container, Stack, Typography } from "@mui/material";
import { alpha } from "@mui/material/styles";
import { useNavigate } from "react-router-dom";

import DashboardIcon from "@mui/icons-material/SpaceDashboardOutlined";
import AlarmIcon from "@mui/icons-material/NotificationsActiveOutlined";
import MatchIcon from "@mui/icons-material/FactCheckOutlined";
import MailIcon from "@mui/icons-material/MarkEmailReadOutlined";
import AttachIcon from "@mui/icons-material/DescriptionOutlined";
import InsightsIcon from "@mui/icons-material/InsightsOutlined";

import { api } from "../api";

const BRAND_DARK = "#0b1020";
const BRAND_PANEL = "#111a33";

const FEATURES: { icon: React.ReactNode; title: string; body: string }[] = [
  { icon: <DashboardIcon />, title: "Centralized pipeline", body: "Track every application across Applied, Waiting, Interview, Offer, Rejected and Ghosted — drag to update." },
  { icon: <AlarmIcon />, title: "Smart follow-ups", body: "Reminders surface what needs attention next, with a grounded draft ready to review and send." },
  { icon: <MatchIcon />, title: "Honest CV match", body: "A deterministic keyword-coverage score with matched vs missing skills — not an opaque black box." },
  { icon: <MailIcon />, title: "Email correspondence", body: "Link Gmail threads to a job; new replies appear automatically without re-importing." },
  { icon: <AttachIcon />, title: "Attachments & docs", body: "Keep resumes, cover letters and portfolios versioned per application, right where you need them." },
  { icon: <InsightsIcon />, title: "Dashboard & insights", body: "Response rates, funnel, time-in-stage and skill demand across your whole search." },
];

const STEPS: { n: number; title: string; body: string }[] = [
  { n: 1, title: "Import", body: "Paste a job URL or use the bookmarklet — we parse the role into structured fields." },
  { n: 2, title: "Match", body: "See how your CV covers the role: matched keywords and the gaps to close." },
  { n: 3, title: "Tailor", body: "AI drafts a tailored CV and cover letter — you review every word before it goes out." },
  { n: 4, title: "Track", body: "Move it through the pipeline; documents, notes and history stay attached." },
  { n: 5, title: "Follow up", body: "Linked email threads and reminders keep momentum with grounded replies." },
  { n: 6, title: "Analyze", body: "See what's working — response rate, funnel and time-in-stage — and focus your effort." },
];

const PRICING: { name: string; price: string; cadence: string; highlight: boolean; features: string[]; cta: string }[] = [
  { name: "Free", price: "£0", cadence: "forever", highlight: false, cta: "Get started", features: ["Unlimited job tracking & pipeline", "One-click capture (bookmarklet + PWA)", "Deterministic CV↔job match score", "3 AI CV tailors / month"] },
  { name: "Pro", price: "£9", cadence: "/ month · billed monthly or yearly", highlight: true, cta: "Start Pro", features: ["Everything in Free", "Unlimited AI CV & cover-letter tailoring", "CV versions + factuality guardrail", "Gmail correspondence CRM", "Analytics drill-downs"] },
  { name: "Bring your own key", price: "£3", cadence: "/ month + your AI key", highlight: false, cta: "Get started", features: ["Everything in Pro", "Use your own Gemini / Groq key", "Unlimited AI at provider cost", "Privacy-first & self-host friendly"] },
];

export default function LandingPage() {
  const navigate = useNavigate();
  const [checking, setChecking] = useState(true);

  // If the visitor already has a session, send them straight into the app.
  useEffect(() => {
    let active = true;
    api
      .get("/auth/me")
      .then(() => { if (active) navigate("/jobs", { replace: true }); })
      .catch(() => { if (active) setChecking(false); });
    return () => { active = false; };
  }, [navigate]);

  if (checking) {
    return (
      <Box sx={{ minHeight: "100vh", display: "grid", placeItems: "center", bgcolor: BRAND_DARK }}>
        <Typography sx={{ color: "#94a3b8" }}>Loading…</Typography>
      </Box>
    );
  }

  const gradientText = {
    background: "linear-gradient(90deg,#6366f1,#22d3ee)",
    WebkitBackgroundClip: "text",
    WebkitTextFillColor: "transparent",
  } as const;

  return (
    <Box sx={{ bgcolor: "background.default" }}>
      {/* Top bar */}
      <Box sx={{ position: "sticky", top: 0, zIndex: 10, bgcolor: alpha(BRAND_DARK, 0.85), backdropFilter: "blur(8px)", borderBottom: `1px solid ${alpha("#ffffff", 0.08)}` }}>
        <Container maxWidth="lg">
          <Stack direction="row" alignItems="center" justifyContent="space-between" sx={{ height: 64 }}>
            <Stack direction="row" alignItems="center" spacing={1.25}>
              <Box sx={{ width: 30, height: 30, borderRadius: "8px", background: "linear-gradient(135deg,#6366f1,#22d3ee)", display: "grid", placeItems: "center", color: BRAND_DARK, fontWeight: 900 }}>✓</Box>
              <Typography sx={{ color: "#fff", fontWeight: 800, fontSize: 20 }}>JobTrack</Typography>
            </Stack>
            <Button variant="contained" onClick={() => navigate("/login")} sx={{ background: "linear-gradient(90deg,#6366f1,#22d3ee)", color: "#0b1020", fontWeight: 700 }}>
              Sign in
            </Button>
          </Stack>
        </Container>
      </Box>

      {/* Hero */}
      <Box sx={{ background: `radial-gradient(1200px 500px at 80% -10%, ${alpha("#6366f1", 0.35)}, transparent), linear-gradient(180deg, ${BRAND_DARK}, ${BRAND_PANEL})`, color: "#fff", py: { xs: 8, md: 12 } }}>
        <Container maxWidth="lg">
          <Box sx={{ maxWidth: 760 }}>
            <Box sx={{ display: "inline-block", px: 1.5, py: 0.5, borderRadius: 999, bgcolor: alpha("#ffffff", 0.08), color: "#a5b4fc", fontSize: 13, fontWeight: 600, letterSpacing: 0.5, mb: 3 }}>
              AI-ASSISTED JOB SEARCH WORKSPACE
            </Box>
            <Typography component="h1" sx={{ fontWeight: 800, fontSize: { xs: 40, md: 60 }, lineHeight: 1.05, mb: 2 }}>
              Run your job search without losing <Box component="span" sx={gradientText}>the thread</Box>.
            </Typography>
            <Typography sx={{ color: "#94a3b8", fontSize: { xs: 17, md: 20 }, mb: 4 }}>
              Import a role, tailor your CV, track every application, and keep recruiter correspondence tied to the
              right job — all in one focused workspace. Assistive, never autonomous: you approve every draft.
            </Typography>
            <Stack direction={{ xs: "column", sm: "row" }} spacing={2}>
              <Button size="large" variant="contained" onClick={() => navigate("/login")} sx={{ background: "linear-gradient(90deg,#6366f1,#22d3ee)", color: "#0b1020", fontWeight: 800, px: 4, py: 1.25 }}>
                Get started
              </Button>
              <Button size="large" variant="outlined" href="#features" sx={{ color: "#e2e8f0", borderColor: alpha("#ffffff", 0.25), px: 3, py: 1.25 }}>
                See features
              </Button>
            </Stack>
            <Typography sx={{ color: "#64748b", fontSize: 14, mt: 3 }}>
              React · TypeScript · ASP.NET Core · EF Core · FastAPI AI · Gmail
            </Typography>
          </Box>
        </Container>
      </Box>

      {/* Product preview */}
      <Container maxWidth="lg" sx={{ py: { xs: 6, md: 9 } }}>
        <Box sx={{ textAlign: "center", mb: 5 }}>
          <Typography sx={{ color: "primary.main", fontWeight: 700, letterSpacing: 1, fontSize: 13 }}>SEE IT IN ACTION</Typography>
          <Typography component="h2" sx={{ fontWeight: 800, fontSize: { xs: 26, md: 34 }, mt: 1 }}>Your whole search, at a glance</Typography>
        </Box>
        <Box sx={{ borderRadius: 3, overflow: "hidden", border: "1px solid", borderColor: "divider", boxShadow: 10, mb: 3, bgcolor: "background.paper" }}>
          <Box component="img" src="/mockups/dashboard.svg" alt="JobTrack dashboard — KPIs, funnel, response trend and follow-ups" sx={{ width: "100%", display: "block" }} />
        </Box>
        <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", md: "1fr 1fr" }, gap: 3 }}>
          <Box sx={{ borderRadius: 3, overflow: "hidden", border: "1px solid", borderColor: "divider", boxShadow: 6, bgcolor: "background.paper" }}>
            <Box component="img" src="/mockups/pipeline.svg" alt="Drag-and-drop pipeline board" sx={{ width: "100%", display: "block" }} />
          </Box>
          <Box sx={{ borderRadius: 3, overflow: "hidden", border: "1px solid", borderColor: "divider", boxShadow: 6, bgcolor: "background.paper" }}>
            <Box component="img" src="/mockups/workspace.svg" alt="Per-job workspace with match score, correspondence and attachments" sx={{ width: "100%", display: "block" }} />
          </Box>
        </Box>
        <Typography sx={{ textAlign: "center", color: "text.secondary", fontSize: 13, mt: 2 }}>Interface preview.</Typography>
      </Container>

      {/* Features */}
      <Container id="features" maxWidth="lg" sx={{ py: { xs: 7, md: 10 } }}>
        <Box sx={{ textAlign: "center", mb: 6 }}>
          <Typography sx={{ color: "primary.main", fontWeight: 700, letterSpacing: 1, fontSize: 13 }}>WHAT IT DOES</Typography>
          <Typography component="h2" sx={{ fontWeight: 800, fontSize: { xs: 28, md: 38 }, mt: 1 }}>One workspace for the whole search</Typography>
          <Typography sx={{ color: "text.secondary", fontSize: 18, mt: 1.5 }}>
            Everything from a single import to the final offer — no more spreadsheets and scattered inboxes.
          </Typography>
        </Box>
        <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", sm: "1fr 1fr", md: "1fr 1fr 1fr" }, gap: 3 }}>
          {FEATURES.map((f) => (
            <Box key={f.title} sx={{ p: 3, borderRadius: 3, border: "1px solid", borderColor: "divider", bgcolor: "background.paper", transition: "box-shadow .2s, transform .2s", "&:hover": { boxShadow: 6, transform: "translateY(-2px)" } }}>
              <Box sx={{ width: 48, height: 48, borderRadius: 2.5, display: "grid", placeItems: "center", bgcolor: alpha("#6366f1", 0.12), color: "primary.main", mb: 2 }}>{f.icon}</Box>
              <Typography sx={{ fontWeight: 700, fontSize: 19, mb: 0.75 }}>{f.title}</Typography>
              <Typography sx={{ color: "text.secondary", fontSize: 15 }}>{f.body}</Typography>
            </Box>
          ))}
        </Box>
      </Container>

      {/* How it works */}
      <Box sx={{ background: `linear-gradient(180deg, ${BRAND_DARK}, ${BRAND_PANEL})`, color: "#fff", py: { xs: 7, md: 10 } }}>
        <Container maxWidth="lg">
          <Box sx={{ textAlign: "center", mb: 6 }}>
            <Typography sx={{ color: "#a5b4fc", fontWeight: 700, letterSpacing: 1, fontSize: 13 }}>HOW IT WORKS</Typography>
            <Typography component="h2" sx={{ fontWeight: 800, fontSize: { xs: 28, md: 38 }, mt: 1 }}>From a link to an offer</Typography>
          </Box>
          <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", sm: "1fr 1fr", md: "1fr 1fr 1fr" }, gap: 3 }}>
            {STEPS.map((s) => (
              <Box key={s.n} sx={{ p: 3, borderRadius: 3, border: `1px solid ${alpha("#ffffff", 0.1)}`, bgcolor: alpha("#ffffff", 0.03) }}>
                <Box sx={{ width: 40, height: 40, borderRadius: 999, display: "grid", placeItems: "center", background: "linear-gradient(135deg,#6366f1,#22d3ee)", color: "#0b1020", fontWeight: 900, mb: 1.5 }}>{s.n}</Box>
                <Typography sx={{ fontWeight: 700, fontSize: 18, mb: 0.5 }}>{s.title}</Typography>
                <Typography sx={{ color: "#94a3b8", fontSize: 15 }}>{s.body}</Typography>
              </Box>
            ))}
          </Box>
        </Container>
      </Box>

      {/* Pricing */}
      <Container id="pricing" maxWidth="lg" sx={{ py: { xs: 7, md: 10 } }}>
        <Box sx={{ textAlign: "center", mb: 6 }}>
          <Typography sx={{ color: "primary.main", fontWeight: 700, letterSpacing: 1, fontSize: 13 }}>PRICING</Typography>
          <Typography component="h2" sx={{ fontWeight: 800, fontSize: { xs: 28, md: 38 }, mt: 1 }}>Honest, simple pricing</Typography>
          <Typography sx={{ color: "text.secondary", fontSize: 18, mt: 1.5 }}>
            Billed monthly or yearly — never by the week. Cancel anytime.
          </Typography>
        </Box>
        <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", md: "repeat(3, 1fr)" }, gap: 3, alignItems: "start" }}>
          {PRICING.map((tier) => (
            <Box
              key={tier.name}
              sx={{
                p: 3.5,
                borderRadius: 3,
                position: "relative",
                bgcolor: "background.paper",
                border: "2px solid",
                borderColor: tier.highlight ? "primary.main" : "divider",
                boxShadow: tier.highlight ? 8 : 0,
              }}
            >
              {tier.highlight && (
                <Box sx={{ position: "absolute", top: -13, left: 24, px: 1.5, py: 0.5, borderRadius: 999, background: "linear-gradient(90deg,#6366f1,#22d3ee)", color: "#0b1020", fontSize: 12, fontWeight: 800 }}>
                  Most popular
                </Box>
              )}
              <Typography sx={{ fontWeight: 700, fontSize: 18 }}>{tier.name}</Typography>
              <Stack direction="row" alignItems="baseline" spacing={0.75} sx={{ my: 1.5 }}>
                <Typography sx={{ fontWeight: 900, fontSize: 40, lineHeight: 1 }}>{tier.price}</Typography>
                <Typography sx={{ color: "text.secondary", fontSize: 14 }}>{tier.cadence}</Typography>
              </Stack>
              <Stack spacing={1.25} sx={{ my: 2.5 }}>
                {tier.features.map((f) => (
                  <Stack key={f} direction="row" spacing={1.25} alignItems="flex-start">
                    <Box sx={{ color: "success.main", fontWeight: 900, lineHeight: 1.4 }}>✓</Box>
                    <Typography sx={{ fontSize: 15, color: "text.secondary" }}>{f}</Typography>
                  </Stack>
                ))}
              </Stack>
              <Button
                fullWidth
                variant={tier.highlight ? "contained" : "outlined"}
                onClick={() => navigate("/login")}
                sx={tier.highlight ? { background: "linear-gradient(90deg,#6366f1,#22d3ee)", color: "#0b1020", fontWeight: 800 } : { fontWeight: 700 }}
              >
                {tier.cta}
              </Button>
            </Box>
          ))}
        </Box>
        <Typography sx={{ textAlign: "center", color: "text.secondary", fontSize: 13, mt: 3 }}>
          Prices indicative — assistive, never autonomous: you always review and send. No auto-apply spam.
        </Typography>
      </Container>

      {/* CTA */}
      <Container maxWidth="lg" sx={{ py: { xs: 7, md: 10 } }}>
        <Box sx={{ borderRadius: 4, p: { xs: 4, md: 6 }, background: "linear-gradient(120deg,#0f172a,#1e293b)", color: "#fff", display: "flex", flexDirection: { xs: "column", md: "row" }, alignItems: { md: "center" }, justifyContent: "space-between", gap: 3 }}>
          <Box>
            <Typography sx={{ fontWeight: 800, fontSize: { xs: 24, md: 30 }, mb: 1 }}>Ready to organize your search?</Typography>
            <Typography sx={{ color: "#94a3b8", fontSize: 17 }}>Sign in to start tracking applications, tailoring CVs, and following up with intent.</Typography>
          </Box>
          <Button size="large" variant="contained" onClick={() => navigate("/login")} sx={{ background: "linear-gradient(90deg,#6366f1,#22d3ee)", color: "#0b1020", fontWeight: 800, px: 4, py: 1.25, whiteSpace: "nowrap" }}>
            Sign in →
          </Button>
        </Box>
      </Container>

      {/* Footer */}
      <Box sx={{ borderTop: "1px solid", borderColor: "divider", py: 4 }}>
        <Container maxWidth="lg">
          <Stack direction={{ xs: "column", sm: "row" }} justifyContent="space-between" alignItems="center" spacing={1}>
            <Typography sx={{ color: "text.secondary", fontSize: 14 }}>© {new Date().getFullYear()} JobTrack — a focused workspace for the modern job search.</Typography>
            <Button variant="text" onClick={() => navigate("/login")} sx={{ fontWeight: 700 }}>Sign in</Button>
          </Stack>
        </Container>
      </Box>
    </Box>
  );
}
