; lib/gitea/search.sx — sx-gitea Phase 7: code + issue/PR search.
;
; search-on-sx (haskell-on-sx) does the heavy lifting: the forge builds a
; document corpus SX-side — code files from the default branch head
; (path + blob text), issues (title + body + comment bodies), PRs (title
; + body + review bodies) — embeds it as one Haskell program, and asks
; searchRankTfIdf for ranked doc ids. Queries speak the search query
; language (terms, AND/OR/NOT, "phrases").
;
; Cost model: ONE evaluation parses the Haskell search layers (~seconds),
; extra queries are nearly free. So the core primitive is
; gitea/search-multi — ANY number of corpora and queries in a single
; evaluation (each corpus becomes an idxN binding) — and everything else
; sugars over it. Only the six layers searchRankTfIdf needs are compiled
; (tokenize/index/query/parse/rank/rankq), not the full search/src.
;
; Requires: lib/gitea/{repo,access,web,issues,pr}.sx and their stacks,
; lib/haskell/* + lib/search/{tokenize,index,query,parse,rank,rankq,
; testlib}.sx (search-hk->sx, hk-core, hk-eval-program).

; ── corpus ───────────────────────────────────────────────────────────

(define
  gitea/code-docs
  (fn
    (forge owner name)
    (let
      ((rec (gitea/repo-get forge owner name)))
      (if
        (nil? rec)
        (list)
        (let
          ((grepo (gitea/repo-git forge owner name)))
          (let
            ((head-cid (git/branch-get grepo (get rec :default-branch))))
            (if
              (nil? head-cid)
              (list)
              (let
                ((files (git/commit-files grepo head-cid)))
                (map
                  (fn (p) {:text (str p " " (get files p)) :kind "code" :ref p})
                  (artdag/sort-strings (keys files)))))))))))

(define
  gitea/issue-docs
  (fn
    (forge owner name)
    (map (fn (r) {:text (str (get r :title) " " (get r :body) " " (join " " (map (fn (c) (get c :body)) (get r :comments)))) :kind "issue" :ref (str (get r :number))}) (gitea/issue-records forge owner name))))

(define
  gitea/pr-search-docs
  (fn
    (forge owner name)
    (map (fn (r) {:text (str (get r :title) " " (get r :body) " " (join " " (map (fn (v) (get v :body)) (get r :reviews)))) :kind "pr" :ref (str (get r :number))}) (gitea/pr-records forge owner name))))

(define gitea/search-kinds-all (list "code" "issue" "pr"))

(define
  gitea/repo-docs
  (fn
    (forge owner name kinds)
    (filter
      (fn (d) (contains? kinds (get d :kind)))
      (concat
        (gitea/code-docs forge owner name)
        (concat
          (gitea/issue-docs forge owner name)
          (gitea/pr-search-docs forge owner name))))))

(define
  gitea/visible-docs
  (fn
    (forge user kinds)
    (reduce
      (fn
        (acc full)
        (let
          ((p (gitea/split-full full)))
          (concat
            acc
            (map
              (fn (d) (assoc d :repo full))
              (gitea/repo-docs forge (get p :owner) (get p :name) kinds)))))
      (list)
      (gitea/visible-repos forge user))))

; ── haskell program assembly ─────────────────────────────────────────

; only the layers searchRankTfIdf needs — parsing is the dominant cost
(define
  gitea/search-src
  (str
    search/tokenize-src
    "\n"
    search/index-src
    "\n"
    search/query-src
    "\n"
    search/parse-src
    "\n"
    search/rank-src
    "\n"
    search/rankq-src
    "\n"))

(define
  gitea/hk-escape
  (fn
    (s)
    (replace
      (replace (replace (replace (or s "") "\\" "\\\\") "\"" "\\\"") "\n" "\\n")
      "\t"
      "\\t")))

; <name> = indexDoc k "text_k" ( ... (indexDoc 1 "text_1" emptyIndex))
(define
  gitea/index-binding
  (fn
    (idxname docs)
    (str
      idxname
      " = "
      (reduce
        (fn
          (acc pair)
          (str
            "indexDoc "
            (first pair)
            " \""
            (gitea/hk-escape (get (nth pair 1) :text))
            "\" ("
            acc
            ")"))
        "emptyIndex"
        (map-indexed (fn (i d) (list (+ i 1) d)) docs))
      "\n")))

(define
  gitea/hk-search-eval
  (fn
    (extra)
    (search-hk->sx
      (hk-deep-force
        (get
          (hk-eval-program (hk-core (str gitea/search-src extra)))
          "result")))))

; THE core: corpora = (docs ...), specs = ({:corpus i :query q :n n} ...).
; One haskell evaluation; => one ranked {:kind :ref (:repo)} list per spec.
(define
  gitea/search-multi
  (fn
    (corpora specs)
    (let
      ((bindings (join "" (map-indexed (fn (i docs) (gitea/index-binding (str "idx" i) docs)) corpora)))
        (exprs
          (map
            (fn
              (s)
              (if
                (empty? (nth corpora (get s :corpus)))
                "[]"
                (str
                  "take "
                  (get s :n)
                  " (searchRankTfIdf \""
                  (gitea/hk-escape (get s :query))
                  "\" idx"
                  (get s :corpus)
                  ")")))
            specs)))
      (let
        ((id-lists (gitea/hk-search-eval (str bindings "result = [" (join ", " exprs) "]\n"))))
        (map-indexed
          (fn
            (si ids)
            (let
              ((docs (nth corpora (get (nth specs si) :corpus))))
              (map
                (fn
                  (i)
                  (let
                    ((d (nth docs (- i 1))))
                    (if (get d :repo) {:repo (get d :repo) :kind (get d :kind) :ref (get d :ref)} {:kind (get d :kind) :ref (get d :ref)})))
                ids)))
          id-lists)))))

; many queries against ONE corpus, still one evaluation
(define
  gitea/search-many
  (fn
    (docs queries n)
    (if
      (empty? docs)
      (map (fn (q) (list)) queries)
      (gitea/search-multi (list docs) (map (fn (q) {:n n :query q :corpus 0}) queries)))))

; ── repo-scoped search ───────────────────────────────────────────────

(define
  gitea/search-repo
  (fn
    (forge owner name query kinds n)
    (first
      (gitea/search-many
        (gitea/repo-docs forge owner name kinds)
        (list query)
        n))))

(define
  gitea/search-code
  (fn
    (forge owner name query n)
    (gitea/search-repo forge owner name query (list "code") n)))

(define
  gitea/search-issues
  (fn
    (forge owner name query n)
    (gitea/search-repo forge owner name query (list "issue") n)))

(define
  gitea/search-prs
  (fn
    (forge owner name query n)
    (gitea/search-repo forge owner name query (list "pr") n)))

; ── global search over visible repos ─────────────────────────────────

(define
  gitea/search-visible
  (fn
    (forge user query kinds n)
    (first
      (gitea/search-many
        (gitea/visible-docs forge user kinds)
        (list query)
        n))))

; ── web ──────────────────────────────────────────────────────────────

(define gitea/w-query-param (fn (req name) (get (get req :query) name)))

(define
  gitea/w-search-kinds
  (fn
    (req)
    (let
      ((k (gitea/w-query-param req "kind")))
      (if
        (contains? gitea/search-kinds-all k)
        (list k)
        gitea/search-kinds-all))))

(define
  gitea/w-search-item
  (fn
    (owner name r)
    (let
      ((kind (get r :kind)) (ref (get r :ref)))
      (cond
        ((= kind "code")
          (str
            "<li class=\"code\"><a href=\"/"
            owner
            "/"
            name
            "/blob/main/"
            ref
            "\">"
            (dream-escape ref)
            "</a></li>"))
        ((= kind "issue")
          (str
            "<li class=\"issue\"><a href=\"/"
            owner
            "/"
            name
            "/issues/"
            ref
            "\">#"
            ref
            "</a></li>"))
        (else
          (str
            "<li class=\"pr\"><a href=\"/"
            owner
            "/"
            name
            "/pulls/"
            ref
            "\">#"
            ref
            "</a></li>"))))))

(define
  gitea/w-search-page
  (fn
    (forge req)
    (let
      ((owner (dream-param req "owner"))
        (name (dream-param req "name"))
        (q (gitea/w-query-param req "q")))
      (cond
        ((not (gitea/w-readable? forge req owner name)) (dream-not-found))
        ((or (nil? q) (= q ""))
          (gitea/w-json-status 400 {:error "missing-query"}))
        (else
          (gitea/w-page
            (str "search: " q)
            (str
              "<h1>Search</h1><p>"
              (dream-escape q)
              "</p><ul>"
              (join
                ""
                (map
                  (fn (r) (gitea/w-search-item owner name r))
                  (gitea/search-repo
                    forge
                    owner
                    name
                    q
                    (gitea/w-search-kinds req)
                    20)))
              "</ul>")))))))

(define
  gitea/w-api-search-repo
  (fn
    (forge req)
    (let
      ((owner (dream-param req "owner"))
        (name (dream-param req "name"))
        (q (gitea/w-query-param req "q")))
      (cond
        ((not (gitea/w-readable? forge req owner name)) (dream-not-found))
        ((or (nil? q) (= q ""))
          (gitea/w-json-status 400 {:error "missing-query"}))
        (else
          (dream-json-value
            (gitea/search-repo
              forge
              owner
              name
              q
              (gitea/w-search-kinds req)
              20)))))))

(define
  gitea/w-api-search
  (fn
    (forge req)
    (let
      ((q (gitea/w-query-param req "q")))
      (if
        (or (nil? q) (= q ""))
        (gitea/w-json-status 400 {:error "missing-query"})
        (dream-json-value
          (gitea/search-visible
            forge
            (gitea/w-user forge req)
            q
            (gitea/w-search-kinds req)
            20))))))

(define
  gitea/search-routes
  (fn
    (forge)
    (list
      (dream-get
        "/:owner/:name/search"
        (fn (req) (gitea/w-search-page forge req)))
      (dream-get
        "/api/repos/:owner/:name/search"
        (fn (req) (gitea/w-api-search-repo forge req)))
      (dream-get "/api/search" (fn (req) (gitea/w-api-search forge req))))))

(set!
  gitea/route-packs
  (append gitea/route-packs (list gitea/search-routes)))