#!/usr/bin/env bash
# export_tex.sh — collect all files needed to compile a .tex file
# Usage: ./export_tex.sh [manuscript.tex] [output_dir]
#   Defaults: first .tex in current dir; output_dir → ./export

set -euo pipefail

# ── arguments ────────────────────────────────────────────────────────────────
TEX_FILE="${1:-}"
if [[ -z "$TEX_FILE" ]]; then
    TEX_FILE=$(ls *.tex 2>/dev/null | head -1)
    [[ -z "$TEX_FILE" ]] && { echo "No .tex file found."; exit 1; }
fi
[[ -f "$TEX_FILE" ]] || { echo "File not found: $TEX_FILE"; exit 1; }

EXPORT_DIR="${2:-export}"
SRC_DIR="$(dirname "$(realpath "$TEX_FILE")")"
TEX_BASE="$(basename "$TEX_FILE")"

mkdir -p "$EXPORT_DIR"

IMAGE_EXTS=(".pdf" ".png" ".jpg" ".jpeg" ".eps" ".svg" ".PNG" ".JPG" ".JPEG")

# Track already-processed tex files to avoid infinite loops
declare -A VISITED_TEX

# ── helpers ──────────────────────────────────────────────────────────────────
copy_rel() {
    # Copy a file to EXPORT_DIR preserving its path relative to SRC_DIR.
    local src="$1"
    [[ -f "$src" ]] || { echo "  [missing] $src"; return; }
    local rel="${src#$SRC_DIR/}"
    local dest="$EXPORT_DIR/$rel"
    mkdir -p "$(dirname "$dest")"
    cp -v "$src" "$dest"
}

find_recursive() {
    # Find file by basename+ext under SRC_DIR; prefer shallower paths.
    local base="$1"; shift
    local found=""
    for ext in "$@"; do
        # Sort by path depth (fewer slashes = shallower) then alphabetically
        found=$(find "$SRC_DIR" -name "${base}${ext}" \
                | awk '{ print gsub(/\//,"/")" "$0 }' | sort -n | head -1 \
                | cut -d' ' -f2-)
        [[ -n "$found" ]] && break
    done
    echo "$found"
}

copy_image() {
    local img="$1"
    # Normalise: strip leading ./ if present
    img="${img#./}"

    # 1. Try path as written in .tex (relative to SRC_DIR), with/without ext
    if [[ "$img" == *.* ]]; then
        local f="$SRC_DIR/$img"
        if [[ -f "$f" ]]; then copy_rel "$f"; return; fi
    else
        for ext in "${IMAGE_EXTS[@]}"; do
            local f="$SRC_DIR/${img}${ext}"
            if [[ -f "$f" ]]; then copy_rel "$f"; return; fi
        done
    fi

    # 2. Fallback: recursive search by basename only
    local base="${img##*/}"
    local f
    f=$(find_recursive "$base" "${IMAGE_EXTS[@]}")
    if [[ -n "$f" ]]; then
        copy_rel "$f"
    else
        echo "  [missing] $img"
    fi
}

# ── recursive tex processor ───────────────────────────────────────────────────
process_tex() {
    local tex_path
    tex_path="$(realpath "$1")"
    [[ -n "${VISITED_TEX[$tex_path]:-}" ]] && return
    VISITED_TEX["$tex_path"]=1

    [[ -f "$tex_path" ]] || { echo "  [missing tex] $tex_path"; return; }
    copy_rel "$tex_path"

    # \input{file} or \include{file}
    while IFS= read -r inc; do
        # Try with and without .tex extension
        local candidate=""
        for try in "$SRC_DIR/${inc}.tex" "$SRC_DIR/${inc}"; do
            [[ -f "$try" ]] && { candidate="$try"; break; }
        done
        if [[ -n "$candidate" ]]; then
            process_tex "$candidate"
        else
            echo "  [missing tex] $inc"
        fi
    done < <(grep -oP '\\(input|include)\{[^}]+\}' "$tex_path" \
             | grep -oP '(?<=\{)[^}]+' | tr -d '\r')

    # \includegraphics
    while IFS= read -r img; do
        copy_image "$img"
    done < <(grep -oP '\\includegraphics(\[[^\]]*\])?\{[^}]+\}' "$tex_path" \
             | grep -oP '(?<=\{)[^}]+' | tr -d '\r')
}

# ── 1. recurse through all .tex files ────────────────────────────────────────
process_tex "$TEX_FILE"

# ── 2. document class (.cls) ──────────────────────────────────────────────────
CLS=$(grep -oP '\\documentclass\[?[^\]]*\]?\{[^}]+\}' "$TEX_FILE" \
      | grep -oP '(?<=\{)[^}]+' | tr -d '\r' | head -1)
if [[ -n "$CLS" ]]; then
    f=$(find_recursive "$CLS" ".cls")
    if [[ -n "$f" ]]; then
        copy_rel "$f"
    else
        echo "  [system]  ${CLS}.cls (not local, assumed installed)"
    fi
fi

# Collect all files to search for bibliography settings: .tex + any local .cls/.sty
mapfile -t SEARCH_FILES < <(
    printf '%s\n' "${!VISITED_TEX[@]}"
    find "$SRC_DIR" -maxdepth 1 \( -name "*.cls" -o -name "*.sty" \) 2>/dev/null
)

# ── 3. bibliography style (.bst / .bbx) ──────────────────────────────────────
BST=$(grep -rhP '\\bibliographystyle\{[^}]+\}' "${SEARCH_FILES[@]}" 2>/dev/null \
      | grep -oP '(?<=\{)[^}]+' | tr -d '\r' | head -1 || true)
if [[ -n "$BST" ]]; then
    f=$(find_recursive "$BST" ".bst" ".bbx")
    if [[ -n "$f" ]]; then
        copy_rel "$f"
    else
        echo "  [system]  ${BST}.bst (not local, assumed installed)"
    fi
fi

# also copy any local .bbx / .cbx referenced by biblatex style option
# matches both style= and bibstyle=
grep -rhP '\\usepackage.*biblatex' "${SEARCH_FILES[@]}" 2>/dev/null \
    | grep -oP '(?:bib)?style\s*=\s*\{?[^},\]]+' | grep -oP '[^={} \r]+$' \
    | tr -d '\r' | sort -u \
    | while IFS= read -r sty; do
        for ext in ".bbx" ".cbx"; do
            f=$(find_recursive "$sty" "$ext")
            [[ -n "$f" ]] && copy_rel "$f"
        done
    done || true

# ── 4. bibliography database (.bib) ──────────────────────────────────────────
# handles both \bibliography{} (BibTeX) and \addbibresource{} (biblatex)
while IFS= read -r bib; do
    bib="${bib%.bib}"   # strip .bib suffix if already present
    f=$(find_recursive "$bib" ".bib")
    [[ -n "$f" ]] && copy_rel "$f" || echo "  [missing] ${bib}.bib"
done < <({ grep -rhP '\\bibliography\{[^}]+\}' "${SEARCH_FILES[@]}" 2>/dev/null \
               | grep -oP '(?<=\{)[^}]+' | tr ',' '\n' | tr -d ' \r'
           grep -rhP '\\addbibresource\{[^}]+\}' "${SEARCH_FILES[@]}" 2>/dev/null \
               | grep -oP '(?<=\{)[^}]+' | tr -d '\r'; } \
         | sort -u || true)

# ── 5. .bbl (pre-built bibliography, if present) ─────────────────────────────
BBL="$SRC_DIR/${TEX_BASE%.tex}.bbl"
[[ -f "$BBL" ]] && copy_rel "$BBL"

echo ""
echo "Done. Files exported to: $EXPORT_DIR/"