#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
OUT_DIR="${DB_DIAGRAM_OUT_DIR:-${REPO_ROOT}/.artifacts/db-diagrams}"

mkdir -p "$OUT_DIR"

TABLES_TSV="${OUT_DIR}/tables.tsv"
RELATIONS_TSV="${OUT_DIR}/relations.tsv"
DOT_FILE="${OUT_DIR}/database-diagram.dot"
SVG_FILE="${OUT_DIR}/database-diagram.svg"
PNG_FILE="${OUT_DIR}/database-diagram.png"
HTML_FILE="${OUT_DIR}/database-diagram.html"

if ! command -v psql >/dev/null 2>&1; then
  echo "psql is required to generate the database diagram." >&2
  exit 1
fi

export PGCONNECT_TIMEOUT="${PGCONNECT_TIMEOUT:-5}"
export PGHOST="${PGHOST:-localhost}"
export PGPORT="${PGPORT:-5433}"
export PGDATABASE="${PGDATABASE:-socialize}"
export PGUSER="${PGUSER:-sa}"

PSQL_ARGS=(-v ON_ERROR_STOP=1 -X -A -t -F $'\t')
CONNECTION_LABEL="${PGHOST}:${PGPORT}/${PGDATABASE} as ${PGUSER}"

if [[ -n "${DATABASE_URL:-}" ]]; then
  PSQL=(psql "${DATABASE_URL}" "${PSQL_ARGS[@]}")
  CONNECTION_LABEL="DATABASE_URL"
elif docker ps --format '{{.Names}}' 2>/dev/null | grep -qx "socialize-postgres"; then
  PSQL=(docker exec -i socialize-postgres psql -U "$PGUSER" -d "$PGDATABASE" "${PSQL_ARGS[@]}")
  CONNECTION_LABEL="Docker container socialize-postgres/${PGDATABASE} as ${PGUSER}"
else
  PSQL=(psql "${PSQL_ARGS[@]}")
fi

echo "Reading schema from ${CONNECTION_LABEL}..."

if ! "${PSQL[@]}" -c "select 1" >/dev/null 2>&1; then
  echo "Could not connect to PostgreSQL." >&2
  echo "Start infrastructure first, then provide credentials with DATABASE_URL, PGPASSWORD, or ~/.pgpass." >&2
  exit 1
fi

"${PSQL[@]}" > "$TABLES_TSV" <<'SQL'
SELECT
    c.table_schema || '.' || c.table_name AS table_id,
    c.column_name,
    c.udt_name,
    c.is_nullable,
    CASE WHEN pk.column_name IS NULL THEN '' ELSE 'PK' END AS key_type
FROM information_schema.columns c
LEFT JOIN (
    SELECT
        kcu.table_schema,
        kcu.table_name,
        kcu.column_name
    FROM information_schema.table_constraints tc
    JOIN information_schema.key_column_usage kcu
      ON kcu.constraint_catalog = tc.constraint_catalog
     AND kcu.constraint_schema = tc.constraint_schema
     AND kcu.constraint_name = tc.constraint_name
    WHERE tc.constraint_type = 'PRIMARY KEY'
) pk
  ON pk.table_schema = c.table_schema
 AND pk.table_name = c.table_name
 AND pk.column_name = c.column_name
WHERE c.table_schema = 'public'
  AND c.table_name <> '__EFMigrationsHistory'
ORDER BY c.table_name, c.ordinal_position;
SQL

"${PSQL[@]}" > "$RELATIONS_TSV" <<'SQL'
SELECT
    tc.constraint_name,
    kcu.table_schema || '.' || kcu.table_name AS child_table,
    kcu.column_name AS child_column,
    ccu.table_schema || '.' || ccu.table_name AS parent_table,
    ccu.column_name AS parent_column,
    col.is_nullable
FROM information_schema.table_constraints tc
JOIN information_schema.key_column_usage kcu
  ON kcu.constraint_catalog = tc.constraint_catalog
 AND kcu.constraint_schema = tc.constraint_schema
 AND kcu.constraint_name = tc.constraint_name
JOIN information_schema.constraint_column_usage ccu
  ON ccu.constraint_catalog = tc.constraint_catalog
 AND ccu.constraint_schema = tc.constraint_schema
 AND ccu.constraint_name = tc.constraint_name
JOIN information_schema.columns col
  ON col.table_schema = kcu.table_schema
 AND col.table_name = kcu.table_name
 AND col.column_name = kcu.column_name
WHERE tc.constraint_type = 'FOREIGN KEY'
  AND kcu.table_schema = 'public'
  AND kcu.table_name <> '__EFMigrationsHistory'
  AND ccu.table_schema = 'public'
  AND ccu.table_name <> '__EFMigrationsHistory'
ORDER BY child_table, child_column, parent_table, parent_column;
SQL

html_escape() {
  local value="$1"
  value="${value//&/&amp;}"
  value="${value//</&lt;}"
  value="${value//>/&gt;}"
  value="${value//\"/&quot;}"
  printf '%s' "$value"
}

node_id() {
  local value="$1"
  value="${value//./__}"
  value="${value//-/__}"
  printf '%s' "$value"
}

declare -A TABLE_COLUMNS
declare -A TABLE_SEEN
declare -a TABLE_ORDER

while IFS=$'\t' read -r table_name column_name column_type nullable key_type; do
  [[ -n "$table_name" ]] || continue

  if [[ -z "${TABLE_SEEN[$table_name]:-}" ]]; then
    TABLE_SEEN["$table_name"]=1
    TABLE_ORDER+=("$table_name")
  fi

  label="$(html_escape "$column_name")"
  type_label="$(html_escape "$column_type")"
  suffix=""
  [[ "$key_type" == "PK" ]] && suffix=" <FONT POINT-SIZE=\"10\">PK</FONT>"
  [[ "$nullable" == "YES" ]] && suffix="${suffix} <FONT POINT-SIZE=\"10\">nullable</FONT>"

  TABLE_COLUMNS["$table_name"]+=$'    <TR><TD ALIGN="LEFT" PORT="'$(html_escape "$column_name")$'"><FONT FACE="monospace">'"${label}"$'</FONT></TD><TD ALIGN="LEFT"><FONT POINT-SIZE="10">'"${type_label}${suffix}"$'</FONT></TD></TR>\n'
done < "$TABLES_TSV"

{
  cat <<'DOT'
digraph database {
  graph [
    rankdir=LR,
    bgcolor="white",
    pad=0.4,
    nodesep=0.6,
    ranksep=1.0,
    splines=ortho,
    overlap=false
  ];

  node [
    shape=plain,
    fontname="Arial"
  ];

  edge [
    color="#64748b",
    arrowsize=0.7,
    fontname="Arial",
    fontsize=10
  ];

DOT

  for table_name in "${TABLE_ORDER[@]}"; do
    id="$(node_id "$table_name")"
    title="$(html_escape "${table_name#public.}")"
    printf '  %s [label=<\n' "$id"
    printf '  <TABLE BORDER="1" CELLBORDER="1" CELLSPACING="0" CELLPADDING="6" COLOR="#94a3b8">\n'
    printf '    <TR><TD BGCOLOR="#0f766e" COLSPAN="2"><FONT COLOR="white"><B>%s</B></FONT></TD></TR>\n' "$title"
    printf '%s' "${TABLE_COLUMNS[$table_name]}"
    printf '  </TABLE>\n'
    printf '  >];\n\n'
  done

  while IFS=$'\t' read -r constraint_name child_table child_column parent_table parent_column nullable; do
    [[ -n "$constraint_name" ]] || continue
    child_id="$(node_id "$child_table")"
    parent_id="$(node_id "$parent_table")"
    label="$(html_escape "${child_column} -> ${parent_column}")"
    style="solid"
    [[ "$nullable" == "YES" ]] && style="dashed"
    printf '  %s -> %s [label="%s", style="%s"];\n' "$child_id" "$parent_id" "$label" "$style"
  done < "$RELATIONS_TSV"

  printf '}\n'
} > "$DOT_FILE"

if command -v dot >/dev/null 2>&1; then
  dot -Tsvg "$DOT_FILE" -o "$SVG_FILE"
  dot -Tpng "$DOT_FILE" -o "$PNG_FILE"
else
  echo "Graphviz dot was not found; wrote only ${DOT_FILE}." >&2
fi

cat > "$HTML_FILE" <<HTML
<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Socialize Database Diagram</title>
  <style>
    html,
    body {
      margin: 0;
      min-height: 100%;
      font-family: Arial, sans-serif;
      background: #f8fafc;
      color: #0f172a;
    }

    header {
      position: sticky;
      top: 0;
      z-index: 1;
      display: flex;
      gap: 16px;
      align-items: center;
      padding: 12px 16px;
      border-bottom: 1px solid #cbd5e1;
      background: #ffffff;
    }

    header h1 {
      margin: 0;
      font-size: 18px;
      line-height: 1.3;
    }

    header a {
      color: #0f766e;
      font-size: 14px;
      text-decoration: none;
    }

    main {
      padding: 16px;
    }

    .canvas {
      width: max-content;
      min-width: calc(100vw - 32px);
      padding: 16px;
      border: 1px solid #cbd5e1;
      background: #ffffff;
    }

    object {
      display: block;
      min-width: 100%;
      min-height: calc(100vh - 104px);
    }
  </style>
</head>
<body>
  <header>
    <h1>Socialize Database Diagram</h1>
    <a href="./database-diagram.svg">SVG</a>
    <a href="./database-diagram.png">PNG</a>
    <a href="./database-diagram.dot">DOT</a>
  </header>
  <main>
    <div class="canvas">
      <object data="./database-diagram.svg" type="image/svg+xml">
        Open database-diagram.svg or database-diagram.png from this folder.
      </object>
    </div>
  </main>
</body>
</html>
HTML

echo "Wrote:"
echo "  ${HTML_FILE}"
[[ -f "$SVG_FILE" ]] && echo "  ${SVG_FILE}"
[[ -f "$PNG_FILE" ]] && echo "  ${PNG_FILE}"
echo "  ${DOT_FILE}"