import "server-only";

import { sql } from "drizzle-orm";

import { getDb } from "@/db";
import {
  artifactConditions, artifactGroups, artifactRecommendations,
  catalogArtifacts, catalogCharacters, catalogWeapons, guides, guideSections,
  stygianRecommendationGroups, stygianRecommendationItems, stygianSchedules,
  teamCompositions, teamMembers, weaponConditions, weaponRecommendations,
} from "@/db/schema";
import { publicMediaUrl } from "@/lib/media/storage";
import type { AnalyticsCategory, AnalyticsItem, AnalyticsKind, PublicAnalytics } from "./model";

type AggregateRow = {
  source: "guide" | "stygian";
  category: AnalyticsCategory | "summary";
  kind: AnalyticsKind | "guide" | "schedule" | "team";
  key: string;
  count: number;
  name: string | null;
  imageKey: string | null;
  rarity: number | null;
  guideId: string;
  teamSignature: string | null;
};

// Aggregate structured records before joining only the catalog labels and images.
// EXISTS keeps multiple section records from multiplying usage counts.
export async function getPublicAnalytics(): Promise<PublicAnalytics> {
  const rows = await getDb().execute<AggregateRow>(sql`
    with public_guides as (
      select g.id, g.name from ${guides} g where g.is_public = true and g.trashed_at is null
    ), public_sections as (
      select s.guide_id, s.kind from ${guideSections} s
      join public_guides g on g.id = s.guide_id where s.enabled = true
    ), guide_teams as (
      select t.id, t.guide_id from ${teamCompositions} t
      where exists (select 1 from public_sections s where s.guide_id = t.guide_id and s.kind = 'team')
    ), stygian_groups as (
      select g.id, g.kind, g.schedule_id from ${stygianRecommendationGroups} g
      join ${stygianSchedules} s on s.schedule_id = g.schedule_id
    ), stygian_items as (
      select i.*, g.kind as group_kind, g.schedule_id from ${stygianRecommendationItems} i
      join stygian_groups g on g.id = i.group_id
    ), members as (
      select 'guide' as source, 'guide:' || t.guide_id as guide_id, m.team_id,
        m.character_key, m.weapon_key, m.artifact_key, m.second_artifact_key, m.constellation, m.refinement
      from ${teamMembers} m join guide_teams t on t.id = m.team_id
      union all
      select 'stygian', 'stygian:' || i.schedule_id, i.group_id,
        i.catalog_key, i.weapon_key, i.artifact_key, null, i.constellation_level::text, i.refinement::text
      from stygian_items i where i.group_kind = 'team' and i.kind = 'character'
    ), member_builds as (
      select team_id, jsonb_build_array(character_key, weapon_key,
        (select jsonb_agg(key order by key) from (
          select distinct key from (values (artifact_key), (second_artifact_key)) a(key) where key is not null and key <> ''
        ) artifact_sets), constellation, refinement) as build from members
    ), fingerprints as (
      select team_id, md5(jsonb_agg(build order by build::text)::text) as signature from member_builds group by team_id
    ), all_teams as (
      select 'guide' as source, 'guide:' || t.guide_id as guide_id, t.id from guide_teams t
      union all select 'stygian', 'stygian:' || schedule_id, id from stygian_groups where kind = 'team'
    ), team_groups as (
      select t.source, t.guide_id, coalesce(f.signature, md5('[]')) as signature, count(*)::int as count
      from all_teams t left join fingerprints f on f.team_id = t.id
      group by t.source, t.guide_id, coalesce(f.signature, md5('[]'))
    ), usage as (
      select m.source, m.guide_id, f.signature, 'team' as category, v.kind, v.key
      from members m join fingerprints f on f.team_id = m.team_id cross join lateral (values
        ('character', m.character_key), ('weapon', m.weapon_key), ('artifact', m.artifact_key),
        ('artifact', case when m.second_artifact_key <> m.artifact_key then m.second_artifact_key end)
      ) v(kind, key)
      union all
      select 'guide', 'guide:' || c.guide_id, null, 'recommendation', 'weapon', r.weapon_key
      from ${weaponRecommendations} r join ${weaponConditions} c on c.id = r.condition_id
      where exists (select 1 from public_sections s where s.guide_id = c.guide_id and s.kind = 'weapon')
      union all
      select 'guide', 'guide:' || c.guide_id, null, 'recommendation', 'artifact', v.key
      from ${artifactRecommendations} r
      join ${artifactGroups} g on g.id = r.group_id
      join ${artifactConditions} c on c.id = g.condition_id
      cross join lateral (values (r.first_artifact_key),
        (case when r.second_artifact_key <> r.first_artifact_key then r.second_artifact_key end)
      ) v(key)
      where exists (select 1 from public_sections s where s.guide_id = c.guide_id and s.kind = 'artifact')
      union all
      select 'stygian', 'stygian:' || i.schedule_id, null, 'recommendation', v.kind, v.key
      from stygian_items i cross join lateral (values
        ('weapon', case when i.kind = 'weapon' then i.catalog_key when i.kind = 'character' then i.weapon_key end),
        ('artifact', case when i.kind = 'artifact' then i.catalog_key when i.kind = 'character' then i.artifact_key end)
      ) v(kind, key) where i.group_kind = 'unit'
    ), counts as (
      select source, guide_id, signature, category, kind, key, count(*)::int as count
      from usage where key is not null and key <> '' group by source, guide_id, signature, category, kind, key
    ), catalog as (
      select 'character' as kind, key, name, image_key, rarity from ${catalogCharacters}
      union all select 'weapon', key, name, image_key, rarity from ${catalogWeapons}
      union all select 'artifact', key, name, image_key, rarity from ${catalogArtifacts}
    )
    select c.source, c.category, c.kind, c.key, c.count, i.name, i.image_key as "imageKey",
      c.guide_id as "guideId", c.signature as "teamSignature", i.rarity
    from counts c left join catalog i on i.kind = c.kind and i.key = c.key
    union all select 'guide', 'summary', 'guide', '', 1, name, null, 'guide:' || id, null, null from public_guides
    union all select 'stygian', 'summary', 'schedule', '', 1, challenge_name, null, 'stygian:' || schedule_id, null, null from ${stygianSchedules}
    union all select source, 'summary', 'team', '', count, null, null, guide_id, signature, null from team_groups
  `);

  const data: PublicAnalytics = {
    guides: [], teamGroups: [],
    guideCount: 0, stygianScheduleCount: 0, guideTeamCount: 0, stygianTeamCount: 0,
    team: { character: [], weapon: [], artifact: [] },
    recommendation: { weapon: [], artifact: [] },
  };
  const items = new Map<string, AnalyticsItem>();
  for (const row of rows) {
    if (row.category === "summary") {
      if (row.kind === "guide" || row.kind === "schedule") {
        data.guides.push({ id: row.guideId, source: row.source, name: row.name ?? row.guideId });
        if (row.kind === "guide") data.guideCount += row.count;
        else data.stygianScheduleCount += row.count;
      }
      if (row.kind === "team") {
        data.teamGroups.push({ guideId: row.guideId, signature: row.teamSignature!, count: row.count });
        if (row.source === "guide") data.guideTeamCount += row.count;
        else data.stygianTeamCount += row.count;
      }
      continue;
    }
    if (row.kind !== "character" && row.kind !== "weapon" && row.kind !== "artifact") continue;
    if (row.category === "recommendation" && row.kind === "character") continue;
    const id = `${row.category}:${row.kind}:${row.key}`;
    let item = items.get(id);
    if (!item) {
      item = {
        key: row.key, name: row.name ?? row.key,
        imageUrl: row.imageKey ? publicMediaUrl(row.imageKey) : null,
        rarity: row.rarity,
        guideCount: 0, stygianCount: 0, contributions: [],
      };
      items.set(id, item);
      if (row.category === "team") data.team[row.kind].push(item);
      else if (row.kind !== "character") data.recommendation[row.kind].push(item);
    }
    if (row.source === "guide") item.guideCount += row.count;
    else item.stygianCount += row.count;
    item.contributions.push({ guideId: row.guideId, teamSignature: row.teamSignature, count: row.count });
  }
  data.guides.sort((a, b) => a.source.localeCompare(b.source) || a.name.localeCompare(b.name, "th") || a.id.localeCompare(b.id));
  return data;
}